60th

Anniversary

Annual Report
2022

Port and Airport Research Institute Annual Report 2022

Message from the Director General

Creating Port and Airport
Technologies That
Contribute to the World

港湾空港技術研究所長（うみそら研理事）

髙野誠紀Seiki TAKANO
Director General, Port and Airport Research Institute(Executive Director, National Institute of Maritime,
Port and Aviation Technology “Umisora Institute”)

CONTENTS
Outline of Organization������������������������������������� 2p
Basic Policies of Institute Management����������� 3p
Structure of Research Themes in FY 2021������ 4p
Research Themes and Activities in FY 2021��� 5p
Fundamental and Exploratory Research����������14p
Published Research Papers������������������������������ 19p
Outstanding Research Activities����������������������20p
The Open Institute��������������������������������������������� 21p
PARI Events��������������������������������������������������������22p

1 PARI Annual Report 2022

In April 2016, three research institutes – the National Maritime Research Institute (NMRI),
the Port and Airport Research Institute (PARI), and the Electronic Navigation Research Institute (ENRI) – were integrated, the National Institute of Maritime, Port and Aviation Technology(MPAT), (commonly known as “Umisora Institute.”) was launched. We, the Port and Airport
Research Institute (PARI), are going to play a role in the Umisora Institute as a research
institute responsible for survey, research and technological development related to the maintenance of ports and airports, while inheriting our past steps. Since its predecessor, the Portand Harbor Research Institute (PHRI) of the Ministry of Transport (MOT), was established in
1962, the Institute marks a major milestone and has celebrated its 60th anniversary this year.
In its 60-year history, the Port and Airport Research Institute has played a major role, providing technical support for numerous port and airport projects, including the developmentof Kashima Port and the construction of Haneda and Kansai International Airports, and haveachieved internationally recognized research results.
The Port and Airport Research Institute will further expand, deepen the cooperation andintegration of research in different fields by the cooperation with other two integrated institutes (NMRI and ENRI), and maximize the results of research and development by demonstrating the synergistic effect, in addition to the close cooperation with the National Institutefor Land and Infrastructure Management (NILIM), Ministry of Land, Infrastructure, Transport
and Tourism (MLIT).
This annual report summarizes the results for FY2021, the sixth year of the first Medium
to Long-term Plan (FY2016 to FY2022). In the first Medium to Long-term Plan, we will focus
on the four R & D issues; "Coastal Disaster Mitigation and Restoration", "Formation of Infrastructure for Vigorous Economy and Society", "Preservation of Marine Interests and Utilization of Oceans", and "Creation and Utilization of Coastal Environment".
In the "Coastal Disaster Mitigation and Restoration", we are proceeding with research on
development for making decisions on whether or not to put facilities back into service quickly
after an earthquake, and on estimating early inundation damage in the event of a huge tsunami, research on filter materials to prevent reclaimed sand from being sucked out throughgaps in caissons. In "Formation of Infrastructure for Vigorous Economy and Society", we areproceeding with research technology which supports operation of container terminals efficiently, the improvement and development of inspection equipment for offshore structures,and the development of core-less ground survey methods.
In "Preservation of Marine Interests and Utilization of Oceans", we are proceeding withresearch on development of a fender system for automatic vessel berthing/unberthig,
research on multifunctionality such as remote control of marine construction machinery,
and analysis on horizontal resistance characteristics of pile foundations for offshore wind
power generation facilities.
In "Creation and Utilization of Coastal Environment", we are proceeding with research toquantify blue carbon (mitigation effect) and implement the J Blue Carbon Credit program invarious coastal areas, and develop a method for predicting global coastal change according
to climate change, etc.
In carrying out these researches mentioned above, we will be pursuing the two major mottos of our institute, “The Research level is the highest in the world” and “The Research results
are useful the actual projects”. We will be also promoting strategic international activities
such as contributing to the overseas expansion of infrastructure promoted by the national
government and technical support to overseas countries. Furthermore, in order to respondto technical issues across research fields, PARI internally set up five centers (International
Research Center for Coastal Disasters”, “Life Cycle Management Research Center”, “Ocean
Infrastructure and Offshore Wind Energy Research Center”, “Productivity Improvement Center”, and “ Innovation Promotion Center”), and we will be further strengthening cooperation
with the Regional Development Bureaus of the Ministry of Land, Infrastructure, Transport andTourism, which have technology implementation sites, and private companies.
In recent years, natural disasters such as earthquakes, storm surges, and high waves
have intensified, occurred frequently, and the acceleration and deepening of National Resilience is an urgent issue. In view of the uniqueness of our institute as a research institute that
conducts practical research and development closely related to the field under the harshnatural conditions unique to Japan, we will be continuing to utilize the knowledge and humanresources of our institute, in addition, we would like to firmly work on emergency response
and support for restoration in the event of natural disaster, enlightenment related to disasterprevention.
We would greatly appreciate your continued understanding and support.

Outline of Organization
Administrative Staff and Researchers, and Budget
Administrative staff
24

Researchers(Others)
39

Commissioned research income, etc.
2,318 million yen
Operational subsidies
FY 2022
1,220 million yen
Annual Budget
3,538 million yen

Total
109
Researchers(with PhD)
46

* The graph above shows the budget for technical fields related to ports,
waterways, coasts, and airports.

As of April 1, 2022 (In Yokosuka)

Organizational Structure
President

Distinguished
Researchers

Strategic Planning andManagement Office

Auditors

National Institute of Maritime,
Port and Aviation Technology (MPAT)

Vice Presidents(In Yokosuka)

Administration Department

Planning Department

Administrative Coordination andDisaster Prevention Department

Director for Research Planning
Director for Promotion of Intellectual Property Utilization
Administrative Division

National Maritime
Research Institute(NMRI)

Port and Airport
Research Institute(PARI)

Electronic Navigation
Research Institute(ENRI)

Planning, Coordination and Disaster Prevention Division
Facilities Division(In Yokosuka)

Wave Group
Coastal Hydraulic Engineering Department

Maritime Structures Group
Tsunami and Storm Surge Group

Coastal and Ocean Development Department

Coastal and Estuarine Environment Department

Geotechnical Engineering Department

Senior Director forInternational Affairs
Senior Director for Research

Marine Information Group
Coastal and Estuarine Environment Group

Coastal and Estuarine Sediment Dynamics Group
Soil Mechanics and Geo-Environment Group

Fellow
Managing Director for
Research Affairs

Coastal and Ocean Development Group

Soil Dynamics Group
Soil Stabilization Group
Foundations Group

Earthquake Disaster Prevention Engineering Department

Engineering Seismology Group

Earthquake and Structural Dynamics Group
Structural Mechanics Group

Structural Engineering Department

Materials Group
Frontier Technologies for Structures Group

Infrastructure Digital Transformation
Engineering Department

Marine Environment Control System Department

Big Data Technology Group
Meta-Robotics Group

Cyber Construction Technology Group
Marine Pollution Management Group
Marine Environmental Information GroupInternational Research Center for Coastal Disasters Reorganized on April 1, 2017
Life Cycle Management Research Center

Reorganized on April 1, 2013

Ocean Infrastructure and Offshore Wind Energy Reorganized on October 1, 2017
Research Center
Productivity Improvement Research Center
Innovation Promotion Center

Established on April 1, 2017
Established on February 1, 2020

As of April 1, 2022

PARI Annual Report 2022 2

Basic Policies of Institute Management
Medium to Long-term Objectives(FY 2016 to FY 2022)

Medium to Long-term Plan
(FY 2016 to FY 2022)

The Minister of Land, Infrastructure, Transport and Tourism(MLIT) sets Medium to Long-term Objectives for the National
Institute of Maritime, Port and Aviation Technology, National
Research and Development Agency to achieve. These objectives stipulate our operations as follows.

The MLIT sets Medium to Long-term Objectives. In response to such objectives, MPAT sets Medium to Long-term
Plan to achieve the objectives. Among such plans, important
points in maximizing research and development results andimproving the quality of other projects are outlined below.

Basic Policies for Structural Reform of Independent Administrative Institutions were decided in a Cabinet decisionon December 24, 2013 (hereafter called “Basic Policies for
Reform”). Based on these policies, the National Maritime
Research Institute (NMRI), Port and Airport Research Institute (PARI), and Electronic Navigation Research Institute(ENRI), which were National Research and Development
Agencies operated under the jurisdiction of the MLIT, were
integrated into the National Institute of Maritime, Port andAviation Technology (hereafter called “MPAT”) to implement the policies.
Article 2, paragraph 1 of the Act on General Rules stipulates as follows: some clerical tasks and business require
sound implementation from the viewpoint of general welfare including stabilization of people’s life and socioeconomy, but at the same time do not require government-led
implementation. Some of these clerical tasks and businesses face the risk of neglect when their operation is
entrusted to private entities, so MPAT was established toeffectively and efficiently conduct their operation.
In consideration of the previous roles of each institute,
MPAT is required to continue to make full use of its accumulated wealth of knowledge and stature, and to proceedwith research and development according to the Basic
Policies for Reform. In addition, MPAT will constantly review research contents and select research areas to address changes in the social environment. At the same time,
MPAT will more actively engage in research and development activities to solve policy challenges in each field,
such as conducting research in emerging fields.
MPAT has promoted research and development in eachfield, cultivated technological seeds, and accumulated
specialized knowledge. Thanks to MPAT’s legacy, such
multidisciplinary research became viable. In considerationof this background, MPAT will efficiently and effectively
implement multidisciplinary research including “Promoting
the protection of maritime interests and the utilization andapplication of marine-resource/marine-renewable-energy
development and other projects”. Through such implementation, MPAT will help put national policies into practice.
Furthermore, MPAT considers that it is important toreturn the benefits achieved through research and development to society, as well as to cooperate with external
institutes and to widely disseminate research results. In
addition, MPAT is committed to strategically implementing international activities as follows: active participationin projects to formulate international criteria and standards; international promotion of Japanese technologies
and systems through international cooperation; and otheractivities.
As outlined above, MPAT’s missions are based on the
MLIT’s Basic Plan for putting MLIT-recommended policies into practice. Today, Japan faces various important
challenges. By realizing these policies, we can solve suchchallenges.

1. Promotion of multidisciplinary research and other activities
MPAT will efficiently and effectively implement multidisciplinary research spanning research fields of the three pre-integration institutions to contribute to putting the following policies into practice: promotion of ocean utilization, enforcementof international industrial competitiveness, and other policies.

3 PARI Annual Report 2022

2. Research and development of technologies associated withports, waterways, coasts, and airports and other activities
MPAT will focus on the research and development challenges detailed in the following pages, to devise the following
MLIT-recommended initiatives: disaster-prevention and disaster-reduction countermeasures for port and airport facilities;
countermeasures for facility obsolescence of existing structures; and initiatives to create maritime-development hubs.
Among basic research, MPAT also actively engages in research to understand the mechanisms of ocean waves andbeach transformation and principles and phenomena regarding the dynamic behavior of the ground and structures.
MPAT also uses its foresight and flexibility to accurately
address emerging research which might lead to new research results.
3. Returning benefits from research and development results
to society
MPAT will try to resolve technological policy challenges, toaddress disasters and accidents, to enforce bridging functions, to promote and utilize intellectual property rights, andto enhance the transmission of information and publication.
4. Promotion of strategic international activities
MPAT will contribute to international standardization andcooperate with overseas institutions.

MPAT Operation Management
MPAT will focus on rapid decision-making to engage instrategic institutional operations.
MPAT will also hold the following meetings for multi-faceted investigation of various operational agendas from a broad
perspective:
1. Management strategy meetings: In-house meetings formaking decisions on important issues related to the core
principles of MPAT management
2. Board of Directors meetings: Weekly meetings involving all
executives and division managers as well as the three directors of the Administrative, Coordination and Disaster Prevention Department
3. Board of Councilors meetings: Meetings to gather insightsfrom independent experts who have broad and deep knowledge
4. External Evaluation Board: An external body in which third
parties objectively and technically evaluate MPAT’s research

Structure of Research Themes in FY 2021
Research
Field

Research Theme

Research Subtheme

Fundamental Research

Strong motion earthquake observation in port and airport area

Fundamental Research

Investigation of earthquake disaster

Fundamental Research

Development of strong motion estimation method for near-fault strong ground motions

Fundamental Research

Development of new prediction and assessment methods for liquefaction-induced settlement andflows② Research on damage-reduction
techniques against the greatest
earthquakes

Applied Research

Development of countermeasure for early exhibition of seismic performance of coastal facilities③ Research on the interaction ofearthquakes, tsunamis, and high waves
with ground dynamics

Applied Research① Research on strong ground motions
and damage predictions in the case of thegreatest earthquakes

1. Coastal Disaster Mitigation and Restoration

1A Research on Mitigation
and Restoration ofEarthquake Disasters

1B Research on Mitigation
and Restoration of Tsunami
Disasters

1C Research on Mitigation
and Restoration of Storm
Surge and Wave Disasters

Item on the Research Agenda(☆indicates special research*)

Type of Research① Research on ICT-based decision
support systems② Research on the development oftsunami-resistant ports① Research on storm surge, wave andmaximum damage estimation② Research on the technology to reduce
maximum storm surge and wave disasters

2. Formation of Infrastructure for Vigorous Economy andSociety

2A Research on① Research and development forEnhancement of Port andenhancing the operations of ports,
Airport Performance forharbors, and airports
Industrial CompetitivenessApplied Research

Research on prediction method for deformation of coastal facilities afterearthquake motion☆

Fundamental Research
Development Research
Development Research
Development Research
Fundamental Research

A Study on Tsunami Wave Forces on Mangroves and Their Deformation

Fundamental Research

Elucidation of oceanographic phenomena based on central processing and analysis of observation
data

Applied Research

Assessment of possible maximum storm surge hazard by using storm-surge-wave coupled model

Fundamental Research

Improvement of wave prediction model for Coastal Areas of Japan

Development Research

Development of simulation method for port facility inundation due to wave overtopping and outflow

Applied Research

Study on Wave Overtopping and Wave Force on Composite Method Preventing Wave Overtopping

Applied Research

Study on the stability of suction-preventing filter materials against waves

Applied Research

Proposal of evaluation method to estimate the productivity of the container terminal system
introduced AI and ICT technology or other method

Applied Research

Proposal of planning method for automated container terminal by quantitative numerical simulation

Applied Research

Proposal of new technology for container terminal operations

Development Research

Development of an underwater positioning system

Applied Research

2B Research on Life
Cycle Management ofInfrastructures① Research on technologies forprolonging the life of infrastructure

Evaluation of longterm durability of concrete, steel and various materials based on exposure test

Fundamental Research

Development of the performance evaluation method in protective coating for marine structures

Applied Research① Research on techniques to improve or
renew existing facilities
2C Research on
Effective Use of Existing
Infrastructure Facilities

A study on the effectiveness of the wire mesh an airfield rigid pavement

Fundamental Research

Fundamental Research② Research on infrastructure inspection
and diagnosis techniques② Research on effective use andtechniques of treating construction
byproducts

3. Preservation of Marine Interests
and Utilization of Oceans① Study on the preservation and use of
remote islands

Study on the applicability of sustainable materials under marine environments☆ Study on improvement of productivity of concrete works in port structures
Study on application of inspection and diagnosis systems for improvement of performance
evaluation of marine structures

Applied Research
Development Research

Development of adaptive technique for inspection vehicle to disturbance in operation

Applied Research

Development of quality evaluation method for ground improvement using geophysical exploration

Fundamental Research

Study on process leading to rupture of pier structure for high definition of performance regulation

Applied Research

Effect of defective part of solidified body on its internal stability
Development of core-less soil investigation and fundamental study to establish Digital Soil
Mechanics

Fundamental Research
Fundamental Research☆ Study on the volume reduction of dredged soil by electro-osmosis dehydration

Development Research

Development of fender system for automatic ship berthing/unberthing

Applied ResearchTechnical approach to advancement of harbor tranquility in a remote island

Applied Research
3A Research on
Development andUtilization of Oceans

Fundamental Research② Research on infrastructure technology
for utilization and development of oceans

Study of wave force and scouring that affect offshore wind power plants☆

Development Research
Development Research

4. Creation and Utilization of Coastal
Environment

4A Research on
Enhancement andUtilization of Coastal
Ecology② Research on the water-environment
simulation and analysis in inner-bay③ Research on countermeasuretechnologies against sea oil spill
4B Research on Coastal
and Estuarine Processes① Research on coastal protection andmaintenance of waterways and mooringbasinsElucidation of the horizontal resistance characteristics of pile foundations for offshore wind power
plants under various fluctuating loads
Study on multifunctional underwater excavator using machine guidance technology☆ Study of applying acoustic imaging system to ICTconstructions

Applied Research① Research on coastal-ecosystemutilization

Stability assessment of coastal structures subjected to internal erosion orwave-seabed interaction
and development of their countermeasures
Deformation/failure behaviours and reinforcement methods of coastal and geotechnical structuressubjected to waves and water flow
Development of a 3-dimensional simulation model for drift behavior and its application to a
2-dimensional simulation model
Development of technology for early prediction of the inundation damage in major earthquake andtsunami disasters
Development of particle-based numerical wave tank to examine the wide-range suffer process of
port structures by tsunami

Research on load setting method for offshore wind power facilities under waves and winds

Fundamental Research☆ Evaluation of mechanical properties and durability of infrastructure materials in deep sea

Fundamental Research☆

Fundamental Research
Applied ResearchExperimental study on methods for enhancing marine ecological value on gray infrastructure
toward establishing green-gray hybrid structure
Validation of the newly developed global dynamic model for the projection of atmospheric CO2☆
uptake rate and inundation control in shallow coastal ecosystems
Coastal geotechnical/geomorphological design for disaster mitigation and ecological environment

Fundamental Research

Development of the methods for increasing ecosystem functions in eelgrass meadow

Applied Research

Numerical analysis of coastal current by numerical simulation and data assimilation

Fundamental Research

Numerical study on responses of aquatic ecosystem to an environmental change

Development Research

Enhancing platforms for the collection and dissemination of coastal information in enclosed-bay

Applied Research

Applied cross-sectional observation and analysis of atmospheric and oceanographic issues at bay
mouthsDevelopment Research

Development of oil spill response technology for next generation

Fundamental Research

Observation of coastal phenomena at HORS and development of numerical simulation of
topography change for port and surrounding beaches

Fundamental Research
Fundamental Research

Developing future projection model of coastal change in the context of climate change☆ Development of sediment transport control method to minimize harbor siltation* Special research involves high-priority research topics on which PARI must conduct studies intensively. PARI allocates significant human resources and funding to these projects, and also arranges crossfunctional research systems extending beyond the basic organizational structure within PARI as needed, in order to accelerate research.

PARI Annual Report 2022 4

Research Themes and Activities in FY 2021

1A

Research on Mitigation and Restoration of Earthquake Disasters

Background and Objectives

In the event of large-scale disasters such as Nankai Trough mega earthquake and earthquake directly under Tokyo Metropolitan area, it is required
to secure necessary trunk line cargo transportation soon after an earthquake
and to quickly secure the requisite minimum transportation of key emergency
supplies for recovery and reconstruction.
In addition, the interaction of earthquakes, tsunamis, and high waves with theground might cause coastal disasters, so it is necessary to reduce such risks.
Therefore, this research aims to establish techniques for predicting seismic
motions and damage to structures caused by the strongest, long-duration
earthquakes. Furthermore, the research will develop new techniques for reinforcing existing structures for improving their anti-seismic capacity, assessing
damage during on-site damage surveys, and implementing emergency measures. In addition, the research elucidates the phenomenon of tsunami causedby submarine landslides, soil performance against the effects of tsunami, highwaves, and flows, and method of countermeasures.

Research Topics

Research and development on earthquake disaster mitigation and recovery
will be conducted under the following three sub-themes;① Research on strong ground motions and damage predictions in thecase of the greatest earthquakes
We will develop a composite source model for simulating epicenter strong
ground motions that can consider not only the strong ground motions thatare caused by the rupture of deep asperities, which have conventionally beenreflected in structural designs, but also the effects of fault shallow slip as observed during the Kumamoto earthquake, and will examine its validity.

occur in coastal facilities due to seismic motions and proceeded with developing a technology to allow coastal facilities to exhibit their performance at an
early stage.
Research on the interaction of earthquakes, tsunamis, and high waves
with ground dynamics
Concerning the interaction of earthquakes, tsunamis, and high waves withground dynamics, our team proceeded with activities to develop techniques forevaluating the stability of coastal structures against sucking out, sinking, andother adverse phenomena, thus leading to effective countermeasures, and also
to develop methods for evaluating the deformation and failure characteristics ofcoastal geotechnical structures in relation to waves and flows, and for reinforcing the structures against them. In terms of effective novel countermeasures
to better protect against sucking out and sinking, the team proceeded working on sucking out prevention method involving filter layers and caisson joint
transmission wave reduction method that were proposed in the previous year,
by considering a wider range of soil conditions, external forces, and structural
conditions and examining the applicability to various conditions. In FY 2021,
the filter-layer-based sucking out prevention method was implemented on theseawall for protecting the new runway at Naha Airport, while the caisson-joint
transmission wave reduction method was implemented at Yokohama Port. In
addition, both of these methods were included in the partial revision of theTechnical Standards and Commentaries for Ports and Harbors (April 1, 2022).
Without a net fiber material② Research on damage-reduction techniques against the greatest
earthquakes
We will develop techniques that will exhibit in the early period the functions of coastal facilities following earthquakes that involve adding new components to existing facilities and replacing components when damaged byearthquakes.

80% more over of caisson-joint
wave transmission rate

Sinking cycle that
occurred atthree-month intervals③ Research on the interaction of earthquakes, tsunamis, and high waves
with ground dynamics
We will develop effective design and countermeasure technologies to detersucking out, caving, etc. that occur to coastal structures under various dynamic external forces.

Activities in FY 2021

Research on strong ground motions and damage predictions in the caseof the greatest earthquakes
In order to predict waveform and damage in the largest earthquakes, weobserved strong ground motions in ports and airports and organized and analyzed their data, investigated earthquake disasters and their causal factors,
and worked on the development of novel methods for predicting near-source
strong ground motions and liquefaction-induced ground subsidence and flow.
As for the development of a method for predicting near-source strong groundmotions, we have made progress in developing and examining a source
model that is capable of considering not only strong seismic motions that arecaused by the rupture of deep asperities on the faults but also the effects offaults shallow slip. Concerning our activity on a system that enables swift andproper determination of the availability judgement of mooring facilities following earthquakes in an effort to improve surveys of earthquake damage and its
causal factors, our team has been discussing with the MLIT and its Regional
Development Bureaus how to utilize the system and also conducted experiments to test the system on site.
Research on damage-reduction techniques against the greatest earthquakes
Concerning our activity involving damage-reduction technology against thelargest earthquakes, we examined ways to predict the deformation that may

5 PARI Annual Report 2022

With a net fiber material

20% or less of caisson-joint
wave transmission rate

No re-sinking
Application: Kashima Port, Soma Port,
Yokohama Port, Kochi Port

Reduction of caisson-joint waves and suppression ofcollapse by a net fiber material

Research Themes and Activities in FY 2021
Research on Mitigation and Restoration of Tsunami Disasters

Background and Objectives

Since the Great East Japan Earthquake in 2011, we have developed
stable structures against tsunami with overflowing and a numerical simulation model to predict the drifting of debris generated by the destruction of structures. However, complex behaviors of running-up tsunami
on land, and the resulting damages are not fully cleared, and then thepredicting methods yet. In addition, regarding a technique for inundation real-time forecast, which is expected to be utilized for evacuationand other purposes, only data from GPS wave buoys is used; othervaluable data is not fully utilized yet.
In order to switch from a damage-first approach to a countermeasure-first approach to disaster prevention and mitigation, we will conduct research on the establishment of a resilient coastal zone, i.e., onethat can protect human lives against the largest tsunami, prevent catastrophic damage to the social economy, and enable early restoration
and recovery from the disaster.

Research Topics

As our research and development on tsunami mitigation and restoration, the following R&D activities will be conducted.
• For our research on simulation model for tsunami drift object, we are
examining the accuracy of 3-D simulation model of the behavior ofdrift object.
• In the research and development of early inundation damage predicting technology for huge tsunami disasters with wide-area crustal
deformation, our team is developing a new calculation method tomake more efficient crustal deformation prediction, and to confirm
the improvement of the prediction accuracy of tsunami waveforms.
• In a study to develop a large-scale numerical wave tank for a groupof outer facilities, in addition to improving the accuracy of the particle
method model, develop a pre-post GUI and implement an automatic
continuous calculation function for large amount calculations.
• For our study on the effects of tsunami wave force on mangroves
and their deformation, we are analyzing the results of hydraulic modelexperiments conducted the previous year and conducting studies onmangrove roots based on literature and also in the field.

Activities in FY 2021

Movement of
the lower
container

Height [m]Height [m]• We improved the 3-D drift object simulation model that had beendeveloped by the previous year and verified its effectiveness by comparing with experimental results. In addition, we established the local
contact model of drift object for the planar 2-D simulation model, andconfirmed the effectiveness by comparing with experimental results.

nt
ide
Incwave
Water Level [m]Water Level [m]Height [m]Height [m]Falling of
the upper
container

Water Level [m]Water Level [m]Numerical simulation by 3-D model• Estimation of earthquake fault planes is essential for estimating crustal
deformation, however, there was no efficient way to estimate this fromtsunami waveforms. Therefore, we developed an adjoint waveform synthesis method that can instantly evaluate the tsunami waveform at any
observation point. The conventional method requires the assumption ofa fault plane in advance, and its estimation accuracy is reduced when
an earthquake different from the assumed one occurs. The newly developed method can synthesize tsunami waveforms generated from arbitrary wave sources, thereby improving accuracy of tsunami waveform
estimation. We applied this method to the tsunami caused by the 2012
Haida Gwaii earthquake, and it is clear that the method improves prediction performance in terms of both rapidity and accuracy.
Estimation
accuracyHigh
Low

Normalized height

1B

Developed
methodPrevious
research
Observation

Sheehan et al. (2015)

Gusman et al. (2016)

Developed method

Observed tsunami waveforms resulting from the 2012 Haida Gwaii earthquake, comparative waveforms simulated by different methods, and their estimation accuracy• We developed a particle- based
numerical wave tank and a GUI
to accurately and stably handle
fluid motions for complex toEnhanced method tosuppress numericalpography. Moreover, pressure
noises(Chronological change incalculations and water surface
wall-surface pressure)pink line: Existing model
boundary conditions of impact
blue line: Proposed model
water by improving the accuracy
black line: Experimentof numerical noise of impact waNumerical noise improvement
ter was improved. Furthermore, achieved by adjusting the model
we tested anti-scour measures
Rectangular caisson
through the deInflow boundary
veloped numeriTwo different terminal
cal wave tankshapes
① Rectangular caisson
to examine their② Round caisson
applicability to
Tanezaki breakwater
Round caisson
the breakwaters
Particleof actual ports
diameter: 1 m
in major tsunami
Outflow boundary
events.
• As mangroves
Mesh created on the GUI representing
have numerous
the end of the breakwaterroots penetrating
the soil, they are highly resistant to tsunami. To elucidate such characteristics of mangroves, we studied
and analyzed their behavior under
the impact of tsunami in the hydraulic model experiment conducted the previous year. Furthermore,
to investigate the tsunami-resisting
capability of mangrove roots, wetraveled to a mangrove habitat andsurveyed the soil characteristics in- Ground survey near mangrove trees
cluding sand particle size.
PARI Annual Report 2022 6

Research Themes and Activities in FY 2021

1C

Research on Mitigation and Restoration of Storm Surge and Wave Disasters

Background and Objectives

Although Japan has not suffered any major disaster caused by storm
surges or high waves since the Isewan Typhoon (Typhoon Vera) thatravaged the country in September 1959, tropical cyclones in other partsof the world have caused severe damage in recent years, including Hurricane Katrina that struck the U.S. in September 2005 and Typhoon Haiyan that devastated the Philippines in November 2013. In future, global
warming might bring higher storm surges and waves than those wehave experienced in Japan. Therefore, this research is aimed for changing disaster prevention and mitigation measures into a pre-disasterstage from post-disaster one and focuses on how to mitigate damage
by the maximum storm surge and wave conditions and how to rapidly
recover and reconstruct after the damage has occurred. Therefore, we
conduct research to encourage hard and soft measures.

• We conducted cross-section experiments involving upright, overtopping-wave-permeable, double-parapet, and flare type seawalls tomeasure the wave overtopping rate, and calculated their equivalentcrest height coefficients. In the case of the gently sloping seawallthat we tested, it was found that the granular diameter of the moundrubble would cause the water level inside the mound to rise. We also
used the CADMAS-SURF numerical wave flume and learned that
granular diameter settings were important.
• We built a nearly full-scale model of stone backfill and a rubble filter
and applied waves to them to observe the stability of the rubble filter.
It was found that the filter could dissipate waves as high as several
tens of centimeters and so its stability could be evaluated by applying
Hudson’s formula.

Research Topics

Research and development on the theme of mitigation of disasters
caused by storm surges and high waves and disaster recovery cover
the following topics:

Activities in FY 2021

• We organized the wave observation data obtained from the NOWPHAS (Nationwide Ocean Wave information network for Ports and
HArbourS) in 2020 and published it as the NOWPHAS 2020 Annual
Report. According to the data, the previous maximum significant
wave heights recorded at two locations were surpassed, and theannual average significant wave height in the Pacific Ocean off thecoast of Shikoku during the year was lower than the average significant wave height during the past decade.
• We simulated the waves that occurred during Typhoon Faxai in 2019using the spectral model WW3 and discovered that Yokohama Port,
which suffered severe damage from the event, was hit by swells
that had developed outside Tokyo Bay. Furthermore, we calculated
the wave pressure that would impact vertical walls using the nonhydrostatic wave model SWASH and proved that the surf similarity
parameter, Iribarren Number, could be used as an effective indicatorof maximum swash height (wave pressure intensity).
• We conducted a planar experiment simulating a container pier where
inundation would occur due to wave overtopping on quay walls during storm surges and also ran calculations to reproduce the phenomenon. The experiment and calculation elucidated the space-time
distribution of the inundation depth and flow speed behind the quay
walls that no previous field survey of water marks could obtain, andalso shed light on the inflow and outflow rates along the quay walls’
normal line as well as on the planar process of inundation.
• We estimated the storm surges that occurred in Tokyo Bay due to Typhoon Faxai in 2019 by applying the ROMS ocean model and analyzed
the effects of the vertical distribution and temporal change of density
fields on the tide anomaly. In addition, we developed a new method ofcorrecting meteorological fields based on their relation to gradient winds.
7 PARI Annual Report 2022

Wave intensity index (square root of the product of wave height andwave length) during Typhoon Faxai’s passage in 2019

Tide anomaly (m)• For our research to elucidate the oceanographic phenomena basedon ocean observation data, we are continuously processing and analyzing wave observation data (preliminary and final processing, andstatistical analysis).
• For our research project simulating inundation events caused bywaves inside ports, we are conducting an experiment using a planar
model to study the inundation process on quay walls.
• For our study of wave estimation techniques, we are improving thewave model based on its known shortcomings.
• For our research on wave overtopping and force on seawall, we areconducting a model experiment examining the new types of seawallsthat have been suggested in recent years.
• For our research on the stability of filter materials under the impact
of waves, we are conducting a model experiment to examine theirstability when the seawall is under construction, etc.

Yokohama: Observation: WRF

Reproducibility
improved.

: WRF+correction: 〃+density gradient (medium): 〃+density gradient (small): 〃+density gradient (large)

Comparison of tide anomaly calculated under various conditions

Double-parapet seawall experiment

Research Themes and Activities in FY 2021

Research Topics

Research and development were conducted on the following topics
to improve the port and airport functions in order to ensure their global
competitiveness.
For the particular objective of improving container terminal productivity, we are developing a container damage inspection system, evaluating numerical simulations of terminals where ICT, etc. are used, andstudying various implementation plans as part of our efforts to promote
digital transformation at ports and harbors, improve their operational
efficiency, facilitate the implementation of environmental measures, andenhance their overall functions.
In addition, we are conducting research and technological development on a real-time underwater positioning system that will enable remote execution of underwater construction operations, etc.

Activities in FY 2021

(Ship cargo handling efficiency:
containers/h)(1) Proposal of evaluation method to estimate the productivity of
the container terminal system introduced AI and ICT technology orother method
While our study on the parallel container-stacking layout in FY 2019 revealed that the trucks on standby on the premises became excessive withcargo volumes of 1.5 million TEU per year, as the deployment of a similar
number of RTG cranes as MC-3 and MC-4 turned out to be far too few,
our study conducted in FY 2020 showed that the gate efficiency would improve if an automated container damage inspection system was used, andthe perpendicular (vertical) layout would result in fairly high capacity as theautomatic stacking crane (ASC) would be always located on the incoming
chassis side in each lane. As it was previously determined that the automated container damage inspection system could not be installed within
the width of a lane, our study in FY 2021 had a minimal gate separately
installed per lane and compared the perpendicular (vertical) and parallel(horizontal) layouts. We found that while the parallel (horizontal) layout would
have significantly negative effects on ship cargo loading/offloading activities
unless in-yard cargo handling was optimized, the perpendicular (vertical)
layout would result in sufficient capacity. It was also discovered that while
no significant difference would arise between reservation rates of 100%and 50% (Case_1_1 and Case_1_2), more operational adjustments had to
be made to achieve the desired outcome when using the position data aswith Case_2 to have the cranes ready in the container yard in advance. As
described above, AutoMod-powered simulations can enable us to examine

Parallel
Parallel
Parallel
Perpendicular
Perpendicular
Perpendicularvarious future plans by testing different assumptions. As the current Port
Plan includes a cargo-handling volume of roughly 1,000,000 TEU per year,
there should be sufficient excess capacity according to our simulations.
(2) Proposal of planning method for automated container terminalby quantitative numerical simulation
The PIANC finished its WG208 report titled
Planning for Automation of Container Terminals and published it in March 2021. Our teamthen made a Japanese-translated version in FY
2021, in conjunction with other organizations
from the private sector.
In addition, our researchers gave keynote
speeches at the Japan-ASEAN WS and otherevents and shared their knowledge with theworld on digital twins, emulation, and simulation
technologies applicable to container terminals.
(3) Proposal of new technology for container terminal operations
As part of the PRISM (Public/Private R&D Investment Strategic Expansion PrograM) sponsored by the Cabinet Office, we developed an
AI-powered image determination system and conducted its data acquisition test at Daikoku Pier in Yokohama Port during FY2020 with aview to implementing the system in actual port operations in the near
future. This system is capable of making determinations using both image processing and laser measurement data. In addition, we examined
its applicability to PC-18 on Port Island in Kobe Port and prepared its
test manual. In FY 2021, our team aided the MLIT with their on-site
empirical test projects.
Laserscanners(5 units)

Ceiling LED lights Vertical ceiling cameras Angular ceiling cameras(2 units)(2 units)(15 units)

Approx. 5 m

Approx.
1.5 m

Approx. Approx.
1.7 m 0.5 m

on of
Directimovement

Approx.
2m

Photoelectric sensors (14 units)

Approx. 0.9 m

Approx. 1.5 m

Approx. 1 m

PARI is responsible for research and development to help improve
the functions of ports, harbors, and airports across Japan, as part ofthe country’s efforts to improve the international competitiveness of
its industries and promote port, harbor, and airport development in an
efficient and effective manner, as they are vital to the daily activitiesof the nation’s citizens. PARI’s research in these areas covers the following subthemes and goals that are relevant to Japan’s international
competitiveness, encompassing the country’s global strategic port andharbor policy, improvement of airport functions in the Metropolitan Area
(improvement of Haneda Airport), infrastructure export capability, etc.
These topics are comprehensively studied by various departments of
PARI as part of its overall R&D policy.

Approx. 2.5 m

Background and Objectives

Approx. 5.4 m

2A

Research on Enhancement of Port and Airport Performance forIndustrial CompetitivenessBottom photoelectric sensors (2 units)
Vertical side cameras Side LED lights(2 units)(15 units)

Angular side cameras(2 units)

Illustration of the container damage inspection system(prototype installed at Yokohama Port)(4) Development of an underwater positioning system

Our team is conducting research and technological development
on an underwater positioning system that can acquire the position ofany moving objects underwater in real time, eventually with the levelof precision that will be required for application to actual construction
projects. In FY 2021, we examined the designs of floating, mobile, andbase stations that would comprise the system, and created prototypesof some of these components.
Base station

GNSS

Acquire the mobile station’s
position and bearing from thefloating station data.
Display the above data
chart in real time.

Acquire the floating
station’s position.

Wi-Fi or 4G

Transmit acoustic wave
reception time and thefloating station’s position.

Floating
stationPlatform bargecommand by
Acoustic(for extension)

Underwater
construction
machinee.g., underwater backhoe

Mobile station

Transmit acoustic
waves with a regularfrequency.

Mound

PARI Annual Report 2022 8

Research Themes and Activities in FY 2021

2B

Research on Life Cycle Management of Infrastructures

Background and Objectives

The ports, airports and coastal infrastructures that have been in service for along time are increasing, but financial resources and the number of engineers
for facility maintenance are limited. As important port, airport, and coastal infrastructure functions should be maintained, the strategic maintenance, renewal,
and other measures to maintain such functions are strongly required.
Therefore, we are trying to establish methods for structure design and material selection which are excellent in terms of maintenance, and will develop
techniques and technologies regarding various countermeasures for maintenance phase.

Research Topics

Research and development were conducted on infrastructure lifecycle
management with emphasis on the following subthemes:• Research on infrastructure inspection and diagnosis techniques• Research on technologies for prolonging the life of infrastructure

Activities in FY 2021

○ Research on infrastructure inspection and diagnosis techniques• Study on application of inspection and diagnosis systems for improvement of performance evaluation of marine structures
As some parts of marine structures are difficult to inspect by eye, it isnecessary to introduce monitoring using sensors and other devices in orderto evaluate and predict the process of deterioration of their concrete andthe efficacy of measures deployed to suppressdeterioration. In this study,
we developed a technique that can evaluate and predict the performance ofthe structural components as a whole, integrating both numerical analysis
and on-site monitoring. Specifically, we focused on the expansion-induced
deterioration resulting from the alkali silica reaction (ASR) and were able tosuccessfully simulate the aforementioned deterioration process facilitatedby ASR through finite-element analysis. We then developed an analyticalplatform that can examine the structures of components while factoring intheir deterioration conditions and started on-site monitoring of actual marine
structures using the platform.
• Development of adaptive technique for inspection vehicle to disturbancein operation
Concerning ROVs for inspecting
the superstructures of piers, we integrated into them our technology thatwould allow them to deal with external disturbances and improved thecountersteering capability that was
included in the stationary positioning
system (i.e., thrust adjustment, countersteering, etc.) implemented in theprevious year. We then took the pier Stationary-positioning-enabled inspecsuperstructure inspection ROVs to tion ROV for investigating the bottom
three ports (one of which was during surface of a pierthe night) and investigated the bottom surfaces of the pier superstructures there, which allowed us to verify
the effectiveness of the ROVs and their upgraded stationary positioning capability in executing inspection tasks beneath piers where visibility is low.
Furthermore, as the on-site tests investigated different types of piers suchas inclined-pile and jacket-covered pier structures, the applicability of thetechniques being developed to actual piers was verified.

○ Research on technologies for prolonging the life of infrastructure• Evaluation of longterm durability of concrete, steel and various materials
based on exposure test
We set up a long-term exposure test facility to examine a method ofpredicting concrete corrosion induced by chlorine, the cathodic protection
characteristics that affect steel bars in reinforced concrete, the conentrated
corrosion mechanism of steel components, and the cathodic protection
characteristics present near LWL. We also acquired data on the durability ofvarious wood materials in this study.

9 PARI Annual Report 2022

• Development of the performance evaluation method in protective coating
for marine structures
We have been continuously performing exposure tests (for 37 years as of
FY 2021) at the Hazaki Oceanographical Research Station (HORS) to examine various coating methods for protecting steel piles in order to establish
a method for predicting deterioration applicable to protective-coated steel
structures. In addition, we worked on elucidating the deterioration mechanism of petrolatum-coated structures based on the findings from our accelerated weathering and indoor exposure tests along with the aforementioned
exposure tests conducted at the HORS.
We then summarized the results of the study conducted in the previous
year (on the 18-year-old surface-coated pier superstructure) to verify the applicability of the anti-corrosion coating (surface coating method) to concrete
port structures.
• Study on improvement of productivity of concrete works in port structures
In order to solve the problem with pile head joints using precast concretefor installation at piers, we conducted a loading experiment and numericalanalysis involving a 1/2-scale model comprised of steel-pipe piles and RC
beams joined together. For this experiment, we used the commonly usedmethod in road bridge construction for connecting the pile foundation andthe footing to make the pile head joints. The experiment verified that the newly applied method was superior to the jointing method used in the previous
year’s experiment in terms of the structure it created, which allowed the piermodel to sustain its load-bearing performance as the amount of displacement increased. However, as the model’s load-withstanding mechanism involved the steel-pipe piles mainly handling the load on the compression sideand the in-built rebars mainly handling the load on the tension side, we wereable to determine that the decreased stationarity of the pile heads would notpose any issue in operational application.
• Study on the effectiveness of the design and implementation of concrete
pavement at airports
Wire meshs are typically installed on the concrete pavements at airports toprevent the spread of cracks and maintain the integrity of the rebar joints underneath them, while preventing foreign objects from falling into the cracks.
However, the effectiveness of this design and implementation method was
not enough to be proven, so we conducted a study for this purpose. We used
the test pavement that was constructed in the previous year and conducteda dump truck loading experiment on it, with and without wire mesh covering,
to compare the results and determine whether the covering had any effecton the occurrence of cracks, but no significant difference was observed in
the experiment.
○ Study on the applicability of sustainable materials under marine en-

vironments
To create a sustainable society, it is desirable to reduce the use of natural
resources and CO2 emissions when constructing buildings (mainly made ofconcrete). It is also preferable to improve the performance and usable lifespans of structures, and enhance their safety margins against temporal deterioration and natural disasters.
To this end, the use of recycled materials has proven to be effective (various slag frame materials, ground granulated blast-furnace slag, fly ash, etc.).
However, these materials have not yet been widely used in actual construction projects. The non-use of these materials might be due to their undefined
performance requirements, and the lack of a method for evaluating their longterm durability, etc.
To address this, we conducted various activities, including evaluating
the performance characteristics of concrete made of recycled materials (interms of usability in construction, durability, etc.), outlining the performancerequirements that would apply to concrete port structures (mainly non-steelreinforced), examining methods for evaluating their long-term durability, andassessing the applicability of the nature-friendly materials (especially recycled ones) (comprehensive examination of their environmental impacts (CO2emissions, etc.) in addition to their durability that had been covered in previous research), etc.

Research Themes and Activities in FY 2021
Research on Effective Use of Existing Infrastructure Facilities

There is strong demand to improve the functions of existing infrastructure
and use them effectively as possible. Requests include measures to handle increasing cargo volume and larger ships and vessels, diversification of airport
functions, and countermeasures to deal with existing facilities which can no longer be used due to increased external forces and other reasons. In addition, regarding waste disposal sites at ports which accept industrial and non-industrial
waste, there is social demand for the highly effective use of them. On the other
hand, it has become difficult to secure disposal sites which accept soil dredged
from water channels for shipping routes. Accordingly, it is necessary to prolong
the life of soil disposal sites.
Therefore, we will develop the following: techniques to improve the functionsof existing infrastructure and to renew and efficiently change the intended useof existing infrastructure; techniques to reduce or effectively utilize construction
byproducts; and techniques to effectively utilize waste disposal sites at ports.

Research Topics

Research and development were conducted on the following subthemes for
efficient facility renewal, effective use of construction byproduct soil, utilizationof waste disposal sites at sea, etc.
• Research on techniques to improve or renew existing facilities• Research on effective use and techniques of treating construction byproducts• Research on management and utilization of waste disposal sites at sea

Activities in FY 2021

○ Research on techniques to improve or renew existing facilities• Study on process leading to rupture of pier structure for high definition of
performance regulation
While the performance requirements of piers can be broken down into different categories such as usability, repairability, and safety, the current performance
specifications only cover the locations and amounts of residual displacement
and plasticized hinges, etc. and fail to provide rules on their practical usability
and repairability. To address such shortcomings, it is crucial to understand thefracture process of entire pier structures in detail, including the behavior of theircomponents following yielding and plasticization. For this purpose, we examined several performance design concepts that could be applied to piers in the
future, and identified potential issues that might exist with their performance assessment methods. Specifically, we considered an optimal approach to defining the performance requirements of non-anti-seismic facilities in withstanding
accidental limit states and the performance regulations that would be applied
to anti-seismic facilities. In addition, we identified and organized the potential
issues that might exist with each of the performance assessment methods.
• Development of quality evaluation method for ground improvement usinggeophysical exploration
As no effective method currently exists to three-dimensionally observe thestatus of improved materials underground after chemical grout is injected into
inhomogeneous ground to prevent liquefaction, we conducted a study to establish methods of evaluating the quality of improved ground and construction
management based on geophysical surveys that would not require soil sampling. Furthermore, we conducted an laboratory model experiment to examine
the applicability of our geophysical survey method that is capable of real-timemonitoring to the investigation of the changes in ground condition that would
occur following chemical grout injection.

○ Research on effective use and techniques of treating construction by-

products• Development of core-less soil investigation and fundamental study to establish Digital Soil Mechanics
To improve the existing ground survey methods that utilize digital data including CT images and also develop a novel ground survey method, we aredeveloping an “in-situ digital sampling method” that involves X-ray CT scanningof the core of in-situ ground, along with a series of testing and analysis techniques for evaluating the engineering characteristics of the ground based on theacquired CT images.

For this purpose, we used the results of the model experiment conducted in
FY 2020 to improve our drilling machine that has a built-in X-ray CT scanner andconducted another drilling test, which revealed that the drilling was able to penetrate the ground to the specified depth and scan the core there. The images
obtained were so clear that we could discern the gravel particles in the ground.
• Effect of defective part of solidified body on its internal stability
We performed numerical analysis to examine how weak sections would affect the stress-strain relationship of unconfined compression test, varying thestrength ratio of weak and sound sections, weak section size, and the locationsof the weak sections within the specimens. The analysis indicated that, if thesolidified specimens contained some weak sections, the strain at failure would
not increase, while exhibiting the same effects as crack-type disturbances thatwould only result in decreased strength.
In addition, we placed a clay slurry that had been frozen with liquefied nitrogen in a mold, poured a slurry of cement-improved soil into the mold, andcured it to create specimens having unimproved weak sections, and conducter
uniaxial compression test. The uniaxial test, during which the content ratio andlocations of the weak sections were changed in various ways, revealed that the
specimen that had weak sections more widely distributed across its mass wasless affected in terms of its uniaxial strength deterioration.
○ Research on management and utilization of waste disposal sites at sea

On this research topic, we continueto gather information on the needs related
to the land use of the sites and identify the issues involved.
Interface withthe drilling rig

Drilling machine

X-ray
CT scanner

Core tube
Drilling unit

Drilling machine with built-in X-ray
CT scanner and drilling experiment
Injection hole 1
before injection

Injection hole 1, four
minutes after injection

Injection hole 1
after injection

CT image captured underground after drilling

Injection hole 2, 11
Injection hole 2, 30
minutes after injection minutes after injection

Injection hole 2
after injection

Real-time measurement results(top: geotechnical survey; bottom: actual ground condition)
Fully improved
specimen

One clayball (small)

One clay
Two claySix clayballs (small) balls (small) ball (large)
Strengthdecreases.

Weak section
ratio: 0%8%

Six clay balls(small) (weaksection ratio: 48%)

Axial strain (%)

16%
Uniaxial strength (kPa)

Background and Objectives

Uniaxial strength (kPa)

2C

48%

30%

One clay ball(large) (weaksection ratio: 30%)

Axial strain (%)

Comparison of weak-section ratios and peak strengths

PARI Annual Report 2022 10

Research Themes and Activities in FY 2021

3A

Research on Development and Utilization of Oceans

Background and Objectives

Since the 1960s, the importance of marine utilization and development has been pointed
out. Various approaches for this purpose have been taken, but the progress remains inadequate. One of the reasons is the lack of infrastructure at sea as a hub. Therefore, marine hub
ports should be constructed on remote islands including Minamitorishima Island and Okinotorishima Island to promote marine utilization and development. These remote islands are surrounded by severe sea wave environment and severe sea climate for port construction which
are different from those of general ports in main islands. Further technological development isrequired to ensure smooth ship berthing, cargo-handling, and port construction.
Therefore, in this research theme, we will make maximum use of previously accumulated
knowledge regarding waves, sea-bed ground, port structures, and port construction to construct ports on remote islands, and will also promote marine utilization and development. Specifically, we will clarify the characteristics of waves in isolated reef areas, and will develop a new
mooring system for ships. We will also develop technologies for downsizing and reducing theweight of underwater acoustic video cameras, as well as utilization and development.

Research Topics

Research and development are being conducted on the following subjects for the development and utilization of oceans.
• For our development of a fender system for automatic ship berthing/unberthing, we areconducting elemental experiments using a scale model focusing on the adsorption mechanism of the fender system to examine its structural stability including the adsorption effect.
• For our research on underwater construction machines that utilize machine guidance technology to integrate multiple functions, we are creating the basic design of a task information presentation system with which the machines can be adapted to other types of work,
while modifying the foundation-leveler attachment for better adaptation to actual on-site
operations and conducting tests to check the accuracy of the acoustic positioning system.
• For our research on an acoustic imaging system, we are examining the feasibility of implementing the acoustic system in the project for harnessing ICT in dredging, based on the
results of actual sea area dredging experiments that had been conducted by the previous
year involving seafloor excavation and soil replacement tasks.
• For our research on the wave force and scouring that affect offshore wind power generation facilities, we are comparing and examining the wave force calculation results that wereobtained in the previous year from the wave force experiment data and numerical simulation(CADMAS-SURF) and are also conducting a large-scale experiment on scour protection
around a circular cylinder.
• For our research on the horizontal resistance characteristics of pile foundations at offshore
wind power generation facilities, we are conducting horizontal loading experiments repetitively under such conditions that are more similar to actual related phenomena, including
a centrifugal model experiment that involves the use of a wave generation machine and amulti-directional loading experiment.
• For our research on the mechanical properties and durability of infrastructure materials inthe deep sea, we are experimentally studying the physical properties of concrete under highwater pressure loading. We have also recovered the test specimens exposed to the deepsea floor in the Nankai Trough (underwater depth of approx. 3,515 m). We are analyzing thedata of the internal water pressure and the strain data monitored during exposure along with
their deterioration condition, etc.

○ For our study on methods for enhancing marine ecological values on gray infrastructure

toward establishing green-gray hybrid infrastructure, we installed several different types of test
specimens along a seawall on the coast of Kitakyushu. Then, we monitored the developmentof algae. Also, we tested several substrate materials (steel, stainless steel, and acryl) to develop
a technique for coral reskinning to clarify the substrate preferred for coral covering. Also, we
performed instrumental analysis to elucidate the mechanism of coral covering. Furthermore,
we analyzed several existing cases of green-gray hybrid infrastructure installations in Japanand other parts of the world. This was done to organize the ideas on the optimal hybrid infrastructure concept in terms of global land space scale and local structure(s)-scale.

○ For the integration of multiple functions in our underwater construction machines utilizing

machine guidance technology, we conducted a review of the functions for adapting our task
information presentation system to other types of work. In addition, we took the machines toNaha Port and Ishigaki Port to examine how well adapted the mounted underwater machine
guidance technology and the remote operation support system were to actual operation sites
and identified potential operational issues that needed to be addressed.

○ For the application of our acoustic imaging system to ICT-based construction projects, we

conducted an underwater visualization experiment using acoustic video cameras for real-timemonitoring of construction tasks as they were being executed, with the eventual goal of achieving autonomous operation of dredging ships. In addition, we established a multibeam datacloud processing system (AIMS) and conducted a surveying test with it (4G and local WiFi) that involved marine telecommunication. Concerning our ICT-based underwater surveying
project, we measured data from the top surfaces of rubble mounds at structures’ foundationsand verified the measurement precision of our technique by comparing the data to the crosssections of the structures’ designs, and also developed a visualization tool, etc. that could beapplied to both underwater and on-ship tasks.

○ For our study of the wave force and scouring that affect offshore wind turbine foundations,

we conducted a large scale hydraulic experiment on the effectiveness of a stone filled net as ascour protection around the circular cylinder of offshore wind turbines at the Large Hydro-Geo
Flume (LHGF).

○ Concerning the research on the horizontal resistance characteristics of the pile foundation at

an offshore wind power generation facility, which is subject to various fluctuating loads, we built
model piles that have larger diameters than the ones made in the previous year and tested themin a pile penetration and horizontal loading experiment in a large soil tank to examine the effectsof pile diameter on the horizontal resistance characteristics of the piles. In addition, we used
a numerical analysis method that could simulate the process of piles penetrating the groundto study how the process would affect the horizontal resistance characteristics of the piles.

Activities in FY 2021

○ Concerning advancement of harbor tranquility in a remote island, we selected a quay bycomplex wave field that is created due to multiple wave reflections and performed wave deformation calculations using NOWT-PARI to obtain wave data penetrating the quay. While a remote island quay is also exposed to a similar wave field in an ocean, we applied both the conventional and our novel methods to calculate the amounts of ship oscillation moored there. The
former is conducted by assuming that all the waves are one-directional and assigning them tothe frequency spectrum, and the latter is conducted by entering the surface wave profiles into
CADMAS-SURF/3D which is improved for calculating with floating objects. We then compared
the calculation results obtained using the two different methods and examined the differences.

○ As for the development of a fender system for automatic ship birthing/unberthing, we con-ducted elemental experiments using a scale model to test the adsorption mechanism of thefender system and were able to verify its structural stability including the adsorption effect.
Also, we reviewed the results of the numerical calculation using a moored ship oscillation simulation to examine the effectiveness of the fender system in terms of its mooring capability, etc.
for ships while they are moored for cargo handling.

11 PARI Annual Report 2022

Visualization of stresscondition underground
Horizontal loading
experiment involving alarge-diameter pile

Numerical analysis of the pile penetration process○ Concerning the research on load setting method for offshore wind turbines in wind andwaves, using meteorological, oceanographic, and structural data corrected in the previous
year, we investigated the dynamic response characteristics of 5MW, 10MW, and 15MW offshore wind turbines to wind and waves through a coupled load analysis called OpenFAST.

○ Concerning the research on the mechanical properties and durability of infrastructure ma-

terials in the deep sea, we performed loading experiment under high water pressure on theinfrastructure materials. Also, we developed the tanks in which low temperature seawater flows.
Thanks to these tanks, we clarified the durability of concrete in a low-temperature seawater.
As a result, the rate of deterioration is different for different types of cement-based materials.
Furthermore, we recovered a circular column specimen from the deep sea floor at 3515 m in
the Nankai Trough exposed for 1 year. The specimen was subjected to instrumental analysis.
We also started a new exposure experiment involving reinforced concrete beam specimens.

Research Themes and Activities in FY 2021

4A

Research on Enhancement and Utilization of Coastal Ecology

Background and Objectives

Rich ecosystems in coastal zones include tidal flats, eelgrass meadows,
and coral reefs, the coastal zones are valuable places for the global environment. However, during high economic growth period, intense socio-economic
activities caused the deterioration of water quality especially in coastal innerbays and enclosed waters, resulting in ecosystem damage. Thanks to subsequent countermeasures, water quality has gradually been improving in somecoastal zones; however, recovery of the coastal zone environment including
ecosystems remains a formidable challenge. Meanwhile, there are new challenges looming, including the need to utilize the coastal zone functions to alleviate climate change and to address the issue of large-scale oil spills from coastal
industrial complexes, etc.
Therefore, we are focusing on activities to help restore the coastal environment, alleviate climate change, and develop technologies to better deal withlarge-scale oil spills. The greenhouse gas absorption effect (blue carbon) of
coastal ecosystems and propose measures to effectively utilize this function. In
addition, we will also develop a system to predict the water environment in Tokyo
Bay and Ise Bay using real-time data, such as the occurrence of red and blue
tides. Furthermore, we will be developing a next-generation oil recovery system
for use by the oil recovery fleet owned by the Ministry of Land, Infrastructure,
Transport and Tourism, along with a new technology to deal with oil spills fromcoastal industrial complexes, etc. that are caused by earthquakes and tsunami.

Research Topics

For research and development on the preservation and utilization of coastal
ecosystems, we are focusing on the following subthemes.
• For our research on examining the previously developed global dynamics
model for predicting the rate of carbon dioxide absorption and flood suppression effects in shallow coastal areas, we are verifying the model by comparing its calculation results with the observed carbon dynamics data, while
consolidating and improving its sub-models that simulate the elements constituting the related processes (wave model, topography and seabed sediment model, and ecological model).
• For our initiative to create coastal topography and geo-designs that would facilitate both disaster mitigation and ecological environment preservation, we
have consolidated all the knowledge and insights that have been obtained
thus far and are in the process of creating and proposing coastal topography
and geo-designs as described above that will be conducive to mitigating
disasters that could be caused by various types of dynamic external forces incoastal areas while promoting biodiversity.
• For our research on techniques to improve the functions of eelgrass meadow
ecosystems, we are examining methods of maintaining and restoring eelgrass meadows while studying model cases from the Seto Inland Sea, etc.
In addition, we are evaluating the function of eelgrass meadows as feeding
grounds by conducting experiments involving seagrass-inhabiting fauna toobserve their feeding behavior, etc.
• For our research and development on techniques for mitigating oil pollution,
we are improving our network-adaptive oil movement prediction system. In
addition, we are conducting experiments to enhance the function of bubble
curtains in terms of their oil collection characteristics, etc., studying the feasibility of implementing bubble curtains on environment management vessels,
and examining techniques for extracting oil from sunken vessels.

Activities in FY 2021

○ For our research on ex-

amining a global dynamics
model for predicting the rateof carbon dioxide absorption and flood suppression
effects in shallow coastal
areas, we developed andexamined our global carbon
circulation and ecosystemmodel and wave and topography model, while continuously gathering related topographical and ecological data

Tidal flat
Yutsun River

Mangroves
Tidal flat

Seaweeds○ For the creation of coastal topography and geo-designs that would promote

both disaster mitigation and ecological environment preservation, we havecreated and proposed our coastal topography and geo-designs as describedabove that can help mitigate disasters that could be caused by various types ofdynamic external forces in coastal areas while promoting biodiversity, based on
our consolidated knowledge and insights obtained thus far.

○ For the monitoring and analysis of atmospheric and oceanographic environ-ments that typically exist at bay mouths, we started conducting atmosphericmonitoring that involves continuous observation and measurement of the atmosphere using small sensors that had been developed by the Japan Agency for
Marine-Earth Science and Technology (JAMSTEC). Meanwhile, we have been
continuously conducting oceanographic monitoring that involves observation ofoceanic flows and water quality. In this connection, we have analyzed massive
amounts of data obtained over the years related to Tokyo Bay and examined thecomplex 3-D flows and water quality components that occur at its bay mouth.

○ For the numerical examination of how aquatic ecosystems respond tochanges in their environments, we have used the numerical simulation modelthat had been developed by the previous year to perform another analysis ofpast data on Ise and Mikawa Bays in order to evaluate the impact of the environmental changes on their topographical and influx load changes as well as how
the changes in water quality there were affected.

○ For the development of techniques to improve the functions of eelgrassmeadow ecosystems, we studied the Seto Inland Sea, etc. as a model caseand organized the data indicating the environmental conditions of eelgrassmeadows and the degree of ease with which their seeds could be introduced in
the region to evaluate more effective eelgrass restoration methods (environmental improvement or transplant). In addition, for the development of methods toevaluate the function of eelgrass meadows as feeding grounds, we conducted
an investigation applying environmental DNA techniques along with a feeding
experiment involving the fauna that inhabit eelgrasses, and evaluated eelgrassmeadows for their feeding ground function.

○ For the elucidation of oceanic flows and water quality conditions in coastal

areas through data assimilation, we analyzed the results of year-round data assimilation that used actual water temperature and salt content data obtained
from Ise Bay, and examined the differences that arose due to different assimilation techniques.

○ For the initiative to improve platforms for gathering and providing coastal

information applicable to major inner bays, we started wave monitoring at themouth of Tokyo Bay using 4K high-resolution imaging technology. In addition,
we started developing a new output platform for distributing information obtained from biodiversity databases, coastal inundation maps, Tokyo Bay statistics, data observed by ferries, etc.

○ For the research and development of new techniques that can be used toCoralsSeaweeds

Iriomote
Islandand performing analysis using GIS. In addition, we conducted on-site observations and experiments related to carbon dynamics in large-scale seaweed farm,
performed numerical model analyses, and prepared a report summarizing theresults. Furthermore, we conducted a trial operation of the new carbon credit
scheme (J-Blue Credit) and published the crediting scheme guidance, which
is a joint project between the Japan Blue Economy Association (JBE) and the
MLIT.

Sea

Mangroves Land
Corals

Bay mouth
borderH.W: Highest water level
MSL: Mean sea level
L.W: Lowest water level

Ecological distribution and cross-sectional topography of the model site

prevent and remove various oil spills caused by natural disasters and otherevents, we have developed a web-based application system that can predict oil
drifts using a web browser from any terminal connected to the internet. Meanwhile, for the development of a new oil recovery system, we are developing asystem that collects oil by combining underwater bubble curtains and terminal
ejectors for oil suction, which have no oil collection boom or oil recovery pump.
The pertinent technologies applied in this system are registered or being registered as our intellectual property rights. In addition, to address the present
phenomenon of drifting pumice clasts, we examined a pumice collection apparatus, partially utilizing the elements of the aforementioned oil recovery system.
PARI Annual Report 2022 12

Research Themes and Activities in FY 2021

4B

Research on Coastal and Estuarine Processes

Background and Objectives

Sediment transport research at the Port and Airport Research Institute began with the study of the depth of movement limit to preventnavigation channel burial, currently the research has shown that themethod of preventing channel burial is not only for sand, but also forsilt. However, in Japan there are still ports and harbors that are in theprocess of being buried. In addition, overseas, there are ports and harbors where much more sediment is expected to be deposited than inJapan, and the technology to deal with the burial of these navigation
channels and anchorage is not sufficient. Meanwhile, many precious
natural beaches were lost during the period of rapid economic growth,and this negative trend is yet to be reversed. Although the many benefits that beaches yield for protection, environmental conservation, andhuman use are clearly recognized, and they are being restored on certain coastlines by taking measures to suppress coastal erosion, global
warming is also expected to exacerbate coastal erosion in the future.
Also, when remote islands and overseas are taken into account, it isimportant to maintain not only beaches but also coral-reef coasts.
PARI is currently focusing on identifying means for effectively preserving both natural coastal topography, such as beaches, mangrove
shorelines, and coral-reef coasts, and artificial coastal features, including navigation channels and anchorage that are crucial for logistics, despite the ongoing trend of climate change. In addition, PARI is working
to predict key changes in coastal erosion as well as sedimentation andsiltation affecting navigation channels and anchorage, and to suggest
measures to effectively address these issues while assuming that thetrend of global warming might persist. Furthermore, we will clarify siltation processes in the estuaries of large rivers, mangroves and intertidal
zone in the Asian countries, and then propose countermeasures against
such phenomena.

Activities in FY 2021

○ For the development of a global-scale prediction method of beachmorphological changes induced by global climate change, we havedeveloped a beach profile change model using deep learning and reproduced temporal beach profile changes and temporal components
obtained from REOF analysis of beach profiles.

○ For the observation activity at the HORS and the development of acoastal topographical change prediction model, we have developed amonitoring method of wave directions with photographic data obtained
from our oceanographic observation cameras. We also examined ourcoastal topographical change prediction model that can consider the
topographical changes due to breaking waves.

○ To elucidate the mechanisms of sediment transport near estuaries

and accumulation in navigation channels and anchorage, a bottom
sediment transport tool was established for the Patimbang coast of Indonesia, taking into account the variation of external wave forces due
to changes in the wind field specific to the Java Sea (i.e., monsoons
and onshore-offshore breezes), and further improved into a numerical
tool that can take into account the detailed geometry of port facilities(navigation channel dredging topography, outer facilities, etc.).

Research Topics

For research and development on the formation and preservation ofcoastal topography, we are focusing on the following.
• For the development of a global-scale prediction method of beachmorphological changes induced by global climate change, we are
generalizing the parameters of an existing equilibrium-based shoreline change model and applying the model to predict future shorelinechanges in various beaches in response to the future climate change
scenarios. We are also developing the beach profile change modelusing deep neural networks.
• For the observation activity at the Hazaki Oceanographical Research
Station (HORS) and the development of a coastal topographicalchange prediction model, we are continuously conducting on-site
observations at the HORS while examining the predicting methods
for topographical changes that would arise around the ports andcoastal areas.
• For the development of sediment transport control methods to mitigate channel and anchorage siltation, we are incrementally applying
the sand-mud-mixture sediment model to actual coastal and harbor
areas. For this purpose, we are developing a simulation system thatreflects the sediment dynamic characteristics of each sea area to bestudied, and to study measures to mitigate the amount of sedimentdeposited in the sea.

13 PARI Annual Report 2022

Sediment transport simulation, reflecting the typical characteristics of changes in wind fields in a tropical region

Fundamental and Exploratory Research
Fundamental Research in FY 2021

The fundamental research of waves, beaches, ground, earthquakes,
environments, etc., is the basis of every study conducted by PARI, andtherefore we are actively working on clarifying principles and phenomena, such as the mechanisms of natural phenomena and dynamic behavior of the ground and structures.
Research theme (Fundamental research)

Cases of Fundamental Research
Development of strong motion estimation method for near-fault
strong ground motions
One of the important factors that determine the characteristics ofstrong seismic motions is site amplification characteristics. The site amplification characteristics can spatially vary significantly, even within thesame port & harbor. For the zoning of site amplification characteristics,
the horizontal-to-vertical Fourier spectral ratio of constant-microtremor(constant-microtremor H/V spectrum) is used. While this constantmicrotremor H/V spectrum is an essential tool for practical purposes,
there is still a debate on how it can be interpreted in terms of elastodynamics. Although some scientists have argued that the spectrum indicates the particle trajectories of Rayleigh waves, a highly plausible newtheory has recently been proposed that claims that the spectral ratioof the reflected waves that occur when horizontal and vertical impulse
excitations are applied at the ground surface represents the constantmicrotremor H/V spectrum (Sanchez-Sesma et al., 2011). To prove theveracity of this theory, a wide range of preconditions must be satisfied,
one of which is that the energy ratio of the S-to-P waves transmitted
through the bedrock must be 2(α/β)3. As for our FY 2021 activity related
to this theory, we conducted theoretical reviews to determine whether
the aforementioned precondition could be met and also published partsof our research findings in a scientific journal in English (Nagasaka andNozu, 2022). According to our study, when S-waves and P-waves are
isotropically incident on a free surface leading to repeated reflections,the energy ratio of the S-to-P waves might increasingly approach 2(α/β)3
regardless of the initial conditions.

1

Strong motion earthquake observation in port and airport area

2

Investigation of earthquake disaster3

Development of strong motion estimation method for near-fault
strong ground motions

4

Development of new prediction and assessment methods forliquefaction-induced settlement and flows

5

Deformation/failure behaviours and reinforcement methods ofcoastal and geotechnical structures subjected to waves and waterflow

6

A Study on Tsunami Wave Forces on Mangroves and Their
Deformation

7

Elucidation of oceanographic phenomena based on central
processing and analysis of observation data

8

Improvement of wave prediction model for Coastal Areas of Japan

9

Evaluation of longterm durability of concrete, steel and various
materials based on exposure test10

Development of the performance evaluation method in protective
coating for marine structures

11

Study on the applicability of sustainable materials under marine
environments

12

Study on process leading to rupture of pier structure for highdefinition of performance regulation

13

Development of core-less soil investigation and fundamental study
to establish Digital Soil Mechanics

Plane waves incident on a free surface from an arbitrary direction (Nagasaka and Nozu, 2022)

14

Study on the volume reduction of dredged soil by electro-osmosis
dehydration

Elucidation of oceanographic phenomena based on central processing and analysis of observation data

15

Elucidation of the horizontal resistance characteristics of pilefoundations for offshore wind power plants under various
fluctuating loads

16

Evaluation of mechanical properties and durability of infrastructurematerials in deep sea

17

Experimental study on methods for enhancing marine ecologicalvalue on gray infrastructure toward establishing green-gray hybrid
structure

18

Validation of the newly developed global dynamic model for the
projection of atmospheric CO2 uptake rate and inundation control
in shallow coastal ecosystems

19

Development of the methods for increasing ecosystem functions
in eelgrass meadow

20

Numerical study on responses of aquatic ecosystem to an
environmental change

21

Observation of coastal phenomena at HORS and developmentof numerical simulation of topography change for port andsurrounding beaches

22

Developing future projection model of coastal change in thecontext of climate change

23

Development of sediment transport control method to minimize
harbor siltation

In this research, we are continuously processing and analyzing
oceanographic observation data obtained by the Nationwide Ocean
Wave Information Network for Ports and HArbours (NOWPHAS) to elucidate the characteristics of wave occurrence at each port, and conducting detailed analysis of the most remarkable marine oceanographic
cases that occurred during the relevant year.
In recent years, waves and storm surges caused by Typhoon Jebi
(Typhoon No. 21) in 2018 and Typhoon Faxai (Typhoon No. 15) in 2019
caused significant damage to port facilities in Osaka Bay and Tokyo
Bay, respectively. However, the waves that were observed and analyzed
during 2020 indicated that no major high waves occurred along thecoast of Japan, as few typhoons formed near Japan or approached it.
On the other hand, as a remarkable example of oceanographic otherthan waves, we analyzed the tidal change (tsunami) reaching to the Pacific coast of the Tohoku region following the eruption of a submarine
volcano in Tonga on January 15, 2022.
As a result of the analysis, a maximum tsunami of about 106 cm
was observed at the tide station at Kuji Port, and a tide level deviation
occurred immediately after the rapid rise and fall in a short period, ofthe onboard barometer on the GPS wave buoys installed offshore, suggesting that at least the initial tide level deviation was caused by an
air vibration phenomenon due to atmospheric waves, we were able toobtain valuable observation results.

PARI Annual Report 2022 14

Atmospheric pressure [hPa]

Fundamental and Exploratory Research

East Aomori buoyNorth Iwate buoy

Tidal level deviation [cm]Central Miyagi buoy

Chronological changes in atmospheric pressure (a) and tidal level deviation (b)measured by GPS wave buoys.
★The figures clearly indicate that the tidal level deviations occurred immediately following the sudden fluctuations in atmospheric pressure.

Evaluation of longterm durability of concrete, steel and various materials based on exposure test

Chlorine ion concentration (kg/m3)

Port and airport facilities are generally required to have the useful
lives of 50 to 100 years. On the other hand, the environment in which
they are located is extremely harsh, being a marine environment. Longterm durability evaluation of various types of construction materials(concrete, steel, anti-corrosion agents, etc.) under such harsh environment will be evaluated based on exposure tests under the same actual
environmental conditions will be expected.
In this study, we are assessing the long-term durability of various
construction materials in marine conditions based on long-term exposure tests conducted under the same actual environmental conditions
as those where they would be used, to provide useful information for
deciding which materials might be suitable for constructing specific facilities. Our main activities conducted in FY 2021 are as follows.
We examined methods of predicting chlorine-induced concrete deterioration (salt diffusion characteristics, etc.) and studied how concreteitself progressively degrades under the effects of seawater, etc.
We conducted exposure and other tests in seawater circulation tanks
and actual environments and examined the intensive corrosion mechanism that affected steel components, along with the cathodic protection
characteristics that would typically manifest near L.W.L.
We studied the durability of various wood materials in seawater and air.
98

1.5 years outdoors
1 year in seawaterindoors
1 year in NaCl

7
6
5
4

Mo-46

3
2
1
0
0

1

2

3

4

5

Distance from surface (cm)Result of test on Moroccan-made concrete(chlorine ion penetration after 1.5 years of exposure)

Study on the volume reduction of dredged soil by electro-osmosis
dehydration
According to increase size of vessels, a large amount of dredged material is occurred every year by dredging for the purpose of maintaining andimproving navigation channels and anchorage areas, as well as for the purpose of increasing the depth in front of the wharf, etc.
It is thought that the consolidation dehydration is effective volume reduction method of dredged soil.

15 PARI Annual Report 2022

One of the measures to dispose of more dredged soil is to reduce thevolume of dredged soil.
One particularly promising approach is consolidation dehydration method by electro-osmosis. The electro-osmotic dehydration is the applicationof electric current to the soil through electrodes that are inserted into thesaturated soil where water can be drawn from the anode to the cathode via
electro-osmosis. By this process, dehydration of pore water occurs on thecathode side.
For this research, the objective of the project is to examine the applicability of electro-osmotic dehydration as an effective method of reducing thevolume of dredged sediments. As for our activities conducted in FY 2021,
we built a consolidation test apparatus that could conduct electricity. We
examined the electro-osmotic consolidation tests of Tokyo Bay clay andKaolin to consider the effectiveness of electro-osmotic dehydration.
Electro-osmosis = Transfer of water and ions (marine clay contains NaCl)

Anode
Water

OH

CI

CI

Removal of water

Cathode
S
Fe

Na

CI
Water

2CI -→CI2+2e- : CI oxidation
Fe→Fe2++2e-: Electrode dissolution

Water
Fe

Na

with negative electric charge

Na Mg : Cations in pore water

Mg
OH: Water molecules with positive

Water electric charge around particles

H

H

CI S

: Anions in pore water

H OH : Electrolysis of water

Fe : Electrode dissolution↑
2H2O+2e-→H2 +2OH : Water reduction(The above occurs in the presence of many chloride ions.)

Illustration of electro-osmosis

Clay sample from Tokyo Bay, before and after the electro-osmotic
consolidation and dehydration test

Evaluation of mechanical properties and durability of infrastructurematerials in deep sea
Japan is a maritime nation surrounded by the sea, with its vast territorial
sea and EEZ mainly consisting of deep sea areas with 200 m or more deep.
As in recent years, the utilization of the deep sea has been considered invarious fields, so the need for deep-sea infrastructure for these activities isalso becoming increasingly recognized.
Infrastructure materials such as cementitious materials and steel infrastructure materials, are important materials for building, however how they
behave in the extreme environment of the deep sea is largely unknown.
In particular, the deep sea zone between 100 to 300 m below sea level isconsidered the optimal range for deploying floating offshore wind turbines,
etc. in the future, for which concrete and other materials could be used
to make anchors, but more basic
data is needed.
In this research project, the objective of which is to evaluate themechanical properties and durability of infrastructure materials
in the deep sea, we first installed
hardened cement-based materials
3500 m below sea level in FY 2020
and recovered them in July 2021. On-site measurement of exposure test
The specimens were then investi- specimens near the seabed at a depthof 3500 m
gated to elucidate their mechanical properties and to assess the characteristics of their surface degradation, etc. We also conducted in-situ measurement of their strain and internal
water pressure to clarify the deformation behavior, etc. of the specimens
under the deep sea. Furthermore, we conducted an indoor experiment using an X-ray CT scanner and clarified the relationship between the processof liquid water infiltration into the hardened cement-based materials and thespecimens’ strain development under high water pressure.

Fundamental and Exploratory Research
Development of the methods for increasing ecosystem functions
in eelgrass meadow

Predation rate (%)

Port development and operations often entail nature conservation
measures, including the development of artificial shallow areas andseagrass meadows. However, as the functions of seagrass meadowswidely vary by location and time, it is not easy to evaluate how theirfunctions would manifest and what they signify in terms of humans’ attempts to protect the environment.
In this study, which focuses on the function of seagrass meadows
as feeding grounds for fishes, etc., we conducted a large-scale on-siteexperiment and revealed that amphipods and other crustaceans would
be good prey for fishes, etc. Furthermore, we developed a low-costresearch method for monitoring the functions of seagrass meadows
using environmental DNA metabarcoding. These findings indicate thatsuch artificial development of seagrass meadows, which provide stable
habitats for gammaridean amphipods and other crustaceans, might allow those seagrass meadows to serve as viable feeding grounds forfishes, etc. We have also identified a practical method of monitoring
their functions.

Useful findings for improving the function of seagrass meadows(Left) Result of on-site experiment in seagrass meadows(Right) Research method utilizing environmental DNA

Developing future projection model of coastal change in the context of climate change
There is a growing need to precisely predict beach morphologicalchanges caused by future sea level rise and wave climate changes,
and to devise appropriate countermeasures for addressing the coastal
disaster risks induced by such coastal changes. In this research project,
we aim to develop a numerical model predicting the shoreline changes
caused by climate change applicable to various beaches based onlong-term beach monitoring data. We have established a prediction
model using LSTM network, which is one of the deep neural networks.
Against this model, it was trained using the daily changes of coastal
topographic section over the past 18 years observed at Hasaki coastand the daily changes of coastal topographic section for the following
six years were predicted, and verified. Although the prediction accuracy of longshore bar morphology was not necessarily good enough,for foreshore topographic is stable for long period, it could be predictedhigh precisely. For climate change and related topographic change ofprediction, further research will be needed.

Exploratory Research in FY 2021
In FY 2021, exploratory research projects based on ingenious and/or advanced ideas that could potentially lead to new research fields for
PARI in the future were carried out.
Impact evaluation and nonlinear dynamic simulation of submarineliquefied flow on floating offshore wind turbine and marine structure
The liquefaction and landslides that occur in the seabed due toearthquakes and waves cause severe damage to marine facilities andstructures, including broken mooring chains and lost anchors that holdoffshore wind turbines in place, collisions among floating structures,
destruction of pile foundations, scouring of their surrounding ground,etc. However, no specific technique currently exists in Japan or elsewhere that can evaluate instances of such damage in detail, including the scale and effects of each incidence of damage, frequency ofdamage occurrence, etc. Therefore, this research project was started
with the objective of developing a numerical computation method (particle method: MPS (moving particle simulation)) that can assess thesequence of impact events that are triggered by the sediment flows
caused by landslides in the seabed that ultimately affect floating offshore wind turbines and other marine structures’ foundations, and examining the applicability of the simulation model to actual floating windturbines and other marine structures that will be deployed in the sea.
To evaluate the characteristics of submarine liquefied flow, we applied to MPS our numerical model, which is capable of analyzing flow
processes where the effective stress is zero and the structural skeletonof the soil is completely destroyed, based on the experimental data andobservation data obtained previously. We also applied the simulation
model to mono-pile offshore wind turbines installed in relatively shallow coastal areas to examine how the impact pressure and liquefied
ground flow affecting the power plants’ foundations influenced the fluid
fields causing sea level changes. These experiments confirmed that the
impact pressure affecting the structures’ foundations was significantly
influenced not only by the impact pressure of the sediment flow but also
by the pressure generated by sea level changes due to disturbances.
Furthermore, we verified that the model could accurately estimate thefrontal cross-section bordering the liquefied ground and the fluid as wellas their two-phase mixture behavior and validated our MPS model’s applicability to the studied phenomena.
Liquefaction

Offshorewind turbine
Submarine Liquef
ied Flowfoundation

Earthquake
Coastal marine
groundGravityfoundation

Submarine
Liquefied Flow

Jacketfoundation

Numerical analysis and visualization data

Coastal marine ground

Monopile Semi-submersible
foundation
foundation

Analogous to dam break

Bottom-fixed (depth of approx. 0 to 60 m) Floating (depth of more than 60 m)

Structure foundation: impact wave force

2-D cross-section

Structure foundation: impact wave force (dimensionless)2-D cross-section(collision)

Hydrostatic pressure (theoretical solution)

Illustration of disaster events triggered by liquefied sediment flow on the seabed and affecting offshore wind turbines, and other key research findings

Experimental research on the mechanical and physiochemical
properties of slag having layered structure

Beach profile predicted by the LSTM network (brown) roughly two
years following the start of calculation and observed profile (blue)

This research project aims to experimentally investigate the mechanicaland physiochemical properties of slag that has a layered structure, with emphasis on slag that are used as backfill material. While it is known that thepresence of slag as well as granular sediment in the ground significantly
affects the mechanical properties of the entire ground due to their unevenmaterial and density structure in terms of granular orientation and otherstructural anisotropy, sand-clay strata, etc., it is expected that the presenceof slag – especially steel slag – might make the ground’s mechanical properties more complicated, because the material itself has a hydraulic property.

PARI Annual Report 2022 16

Fundamental and Exploratory Research
On the other hand, although it has been revealed that the layered structureof granular ground has significantly higher strength (against static compression and liquefaction) than a uniform structure, researches that have identified this mechanism are very limited. In addition, if we could shed more
light on the long-term reactivity of slag and its solidification characteristics,
it would be possible to evaluate the behavior of various ground materials
throughout their lifecycles, which would in turn enable the development of anovel design protocol that factors in their temporal axles.
In this research project, which involved slag typically used as backfill
material along with several different ground specimens for comparison, we
conducted triaxial compression and mechanical tests while focusing on
the degree of their classification and solidification reactivity, and chemical
analysis of the target materials using X-ray imaging, SEM, etc. The triaxial
compression test and the deformation characteristic analysis we conductedusing X-ray CT scan revealed that the parts of the materials’ layered structure that had particularly large granular diameters would exhibit significantly
expansive behavior and that the difference in their deformation behavior
largely contributed to enhancing the strength of their layered structure. In
addition to, our various chemical analyses of the tested slag provided somekey indicators that could be used to quantitatively evaluate the slag’s solidification reactivity. Our next steps in this research include the relationshipbetween the sedimentary structure of ground and its solidification in details
more, which we will use the long-term behavior evaluation of slag.

Observation of thedeformation condition of a layered
structure (verticalfault image obtainedby X-ray CT scan)

Observation of thedeformation condition of a uniform
structure (sameimage acquisition
method as left)

SEM image of slag extracted
from solidified ground(calcium carbonate covering
around the slag and traces ofreactivity seen up to 0.5 mm
from the slag surface)

Coastal disaster monitoring with 4K cameras and analysis of related big data
The fierce sea winds caused by Typhoon Faxai in 2019 caused the highest waves ever officially recorded in Tokyo Bay, leaving the coastal areas
near Yokohama Port severely damaged by destroying many coastal structures and flooding the hinterland. Real-time confirmation of high-definition
surveillance camera images contributes to the identification of disasterareas and early restoration. In addition, understanding the oceanographic
conditions at the time of the disaster through post-disaster analysis is aneffective research method for clarifying the causes of the disasters. With
the rapid spread of 4K cameras in the broadcasting, and medical fields,
and etc., although technological innovation is also progressing in the field ofsurveillance and security cameras, the following two essential criteria must
be met for such cameras to be used for the prevention and mitigation ofcoastal disasters: 1) High-pixel camera to capture wave phenomena; and 2)
all-weather type, capable of taking pictures at night and during storms. Recent innovative technological developments in CMOS sensors are clearing
these conditions, and their potential for use in coastal disaster prevention is
rapidly increasing. Based on this technological trend, this research project
aims to develop a unique monitoring system that utilizes 4K cameras, sothat eventually the coastal surveillance data that will be obtained throughthe system, including footage of port facilities, can be shared with relevant
government agencies and used for disaster prevention and mitigation.
As for the project activities conducted so far, we developed a real-timecoastal disaster surveillance system integrating high-definition 4K IP cameras (image resolution: 3840×2160, 15 fps continuous recording, night photography-enabled) and deployed it on multiple locations to obtain related
big data. We then used the ocean surface luminance spectrum discerned

17 PARI Annual Report 2022

from the obtained 4K video data to estimate corresponding 2-D wave number vectors and succeeded in computing the wave directions. As we havealso been developing an algorithm for estimating wave statistics, if we could
infer wider-ranging wave statistics with it, they could become novel meansof wave observation. The 4K-camera system that we have established canbe installed at any coastal location that has a platform available. Therefore,
if we could share the big data obtained through the system with regional
municipalities and other concerned parties, it would be aid their disastermitigation and elucidate the causes of any disasters they experience.

4K camera images captured at the Kannonzaki radar facility and ocean surface luminance spectrum estimation

Feasibility study on the automation and remote operation of underwater robots utilizing 2D codes
In this study, which aims to enable the automatic operation of underwater
robots using 2D codes, we examined a simple method of providing operating
instructions to underwater robots using QR and other 2D codes. To achieve
this objective, we developed an application software program. This software
could recognize instructions from the 2D code and control an underwater
drone accordingly. In addition, we selected a low-cost and high-speed telecommunication capability camera, for which we fabricated a custom-made2D codewaterproof case and installed it on therecognition camera
drone. We then attached 2D code panels to a pier model located inside a water tank on PARI’s premises and conducted a demonstration experiment
under a 0.2 m wave height condition.
Drone-operating PC +Underwater drone
controller application
In the experiment, we observed theUnderwaterdrone
used in theautomatic drone operation by 2D code
experiment
instructions and identified any potential
issues that might arise.
The experiment indicated that theunderwater drone could recognize theattached 2D code instructions, automatically move to any specified position, and keep the position even amid
the waves. We could also identify several issues, for example, the frequency Experiment in progress amid artificial wavesof the 2D code recognition.
Study on automatic operating methods of inspection underwater
robots of underwater port structures
This research project was conducted toconfirm the underwater condition of emergency structures in the event of a disasterand underwater structures and visual surveyof underwater structures by divers will be
implemented effectively in order to promoteusing to grasp situation in advance, the pur- Robot used in the experimentpose of the project is to automate part of theunderwater robot's navigation.
The robot was automated to acquire images of the underwater portion ofan upright wall of a structure using an underwater robot based on a commercially available underwater drone as the base machine.
First, we installed a wireless communication capability on the base machine to avoid the risk of cable entanglement with target structures. We
then installed a wireless communication antenna on it in order to be able
to receive data from the robot remotely operate it for the operator on land

Fundamental and Exploratory Research
via radio communication (wireless LAN)
Wall surface
when the robot is moving along the water surface. In addition, as it is not possible to communicate with the robot while
it is submerged, we created an external
module that will be attached to the robot
to enable it to operate autonomously.
Underwater
We also installed an underwater camera
robot
on the robot for inspection purposes.
Experiment in progress
We then conducted water tank experiments to test the robot’s autonomous navigation function, which allowed
us to verify the robot’s ability to automatically operate itself while aiming
its underwater camera at the vertical wall and travelling along the structure
while maintaining a specified distance.
Development of a method for exploring corrosion in steel rebars inside reinforced concrete and assessing damage in a manner similar to palpation
Electrochemical impedance spectroscopy (EIS) is a technique commonly used toinspect for any corrosion that may be present in steel rebars inside structures madeof reinforced concrete. As this techniqueinvolves passing electric currents throughthe steel rebars from the concrete’s surface Figure 1: Corrosion diagnosis unit
to measure their corrosion condition, it re- incorporating the new method
quires connecting a power supply tothe rebars through which electricity
is to flow. Therefore, it is often necessary to drill holes into parts of theconcrete to attach lead wires to thesteel rebars inside, which impedes
the inspection operation.
In this research project, we developed a new method that involves
installing several electrodes onto the Figure 2: Data measured by the newconcrete surface to form a separate corrosion diagnosis unit
electric circuit so that EIS can be applied without connecting the steel rebars directly to the power supply. In
other words, this method eliminates
the need to drill holes in the concrete.
We then built a corrosion diagnosis unit (Figure 1) incorporating themethod and compared the measurement data obtained using theconventional method (direct connec- Figure 2: Data measured using thetion to the steel rebars) and this new conventional method
method (no direct connection). Figure 2 indicates sample data measured
using EIS, which is known as a Nyquist plot. As the Nyquist plots obtained
through the two different methods were almost identical, it was proven that
our new method enables EIS without having to drill the concrete.
Feasibility Study on Development of Shirasu Based Capsules for
Bio Self-Healing Materials in Concrete
Cracks that tend to be the starting point of deterioration of concrete
structures can be repaired by concrete itself, repair cracks and maintainthe sound of concrete structures, "self-healing concrete", which has been
attracting attention.
Self-healing concrete is broadly classified into three categories: inorganic, organic, and microbial. Microbial systems are characterized by theirability of function to close cracks through biological metabolism.
In this research project, we focused on the aerobic bacterium Bacillus subtilis var. natto and developed a high-function self-healing concretethat can not only fill cracks by the metabolism of organisms but can also
use the bacterium’s breathing to deprive the concrete of oxygen and thus
suppress corrosion of the steel rebar inside, in addition, we implemented

development of a microcapsule material that can be used to efficiently apply Bacillus subtilis var. natto to concrete. We selected shirasu balloon andshirasu pumice as microcapsule materials, which are both natural pozzolans, to which the Bacillus subtilis var. natto could be absorbed to achieve
micro-encapsulation, it would be also expected a secondary benefit of thistechnique: further concrete precision resulting from the pozzolan reaction of
the volcanic glass.
The photos below show mortar test specimens in which cracks were induced after Bacillus subtilis var. natto had been applied, before they were
exposed in water for a certain period to verify the efficacy of the bacterium
Bacillus subtilis var. natto and microcapsules working in combination. While
the mortar to which the bacterium Bacillus subtilis var. natto was not applied
did not confirm any sign of its cracks being filled, in the specimens to whichshirasu balloon and shirasu pumice had been absorbed the bacterium Bacillus subtilis var. natto, a calcium-derived substance was being depositedin their cracks closed them.

Specimen of shirasu
balloon infused with
Bacillus subtilis var.
natto

Specimen of shirasu
pumice absorbed with
Bacillus subtilis var.
anattoMortar with noinfusion of Bacillus
subtilis var. natto* No crack-fillingobserved.

Observation of mortar test specimens’ ability to self-healing artificiallyinduced cracks

Proposal of Green Transformation (GX) strategy for port structuresto achieve carbon neutrality
With the trend toward global decarbonization gathering pace, efforts are underway to achieve Carbon Neutral Port (CNP) in the Japanese port sector. Thus,
it is becoming increasingly important to minimize CO2 generation in terms of theconstruction of port structures. To efficiently facilitate this process of CO2 emission
mitigation, it is crucial to first quantify and understand the characteristics of the CO2
emissions that occur during port structure construction, and then explore effective
ways to achieve the carbon mitigation goals. However, there is still not enough research on the amounts of CO2 emissions that occur when port structures are built.
In this research project, we organized information on CO2 emission computation methods and quantified the amount of CO2 emissions that typically arise ina project to build a breakwater covered with wave-dissipating concrete blocks.
Our calculations revealed that nearly 90% of the CO2 emissions caused in sucha project mainly arose fromthe material manufacturing
activities, of which roughly
70% was attributable toconcrete. It was also discovered that the majority of theCO2 emissions that resulted
from machine operations
was from the work vessels,
as the machines being oper- CO2 emissions from the construction of breakated on land produced less waters covered with wave-dissipating concrete
CO2. Having clarified the CO2 blocks
emission characteristics, we could determine the direction of our technological development to achieve each of the defined reduction goals, etc. Furthermore, after
carefully investigating the concrete that was responsible for the majority of CO2
emissions, we found that the total CO2 emissions that occurred in each construction project could be reduced by 30–45% simply by switching to the optimal cement type (regular, blast furnace type B, or blast furnace type C). This confirmed
the effectiveness of switching to low-carbon materials where possible and the necessity of developing low-carbon materials that can be applied to and withstandthe marine environment that surrounds port structures. Regarding our initiative todevelop low-carbon materials, we are continuously conducting basic research on
carbon fixation methods that utilize CO2 nano-bubble water and dredged soil toverify their efficacy and identify any potential issues.

PARI Annual Report 2022 18

Published Research Papers
Number of Peer-reviewed papers in FY 2021
Number of papers in Japanese

Number of papers in non-Japanese languages

Total

Rate of papers in non-Japanese language

61

63

124

50.8%

* The above numbers contain proceedings that only reviewed the abstract.

Papers Published in PARI Reports in FY 2021
No.

Title

Author(s)LanguageMonth/Year

60-1-1

Cyclic beach morphological changes in the swash zone due totidal range fluctuations

Masayuki BANNO, Yoshiaki KURIYAMAJapanese

June 2021

60-1-2

Ocean swells induced by the Typhoon Faxai hit Port of
Yokohama in 2019

Hitoshi TAMURA, Koji KAWAGUCHI, Takumu IWAMOTO,
Takashi FUJIKI

Japanese

June 2021

60-1-3

Dynamics of ocean swells in Toyama Bay

Hitoshi TAMURA, Koji KAWAGUCHI, Takashi FUJIKI

Japanese

June 2021

60-1-4

Study on stability of temporary armor units against waves

Kojiro SUZUKI, Hiroki KUBOTA, Tsutomu TANAKA

Japanese

June 2021

60-1-5

Study on wave pressure acting on receding parapet typeseawall

Kojiro SUZUKI, Hiroki KUBOTA, Naoki TSURUTA

Japanese

June 2021

60-1-6

Study of slow slip mechanism on plate boundary fault
decollement zone

Yuri SUGIYAMA, Shinya TACHIBANA, Yoshiyuki MORIKAWA

Japanese

June 2021

60-1-7Development of frictional contact algorithm using weighted
least squares for MPM–rigid body simulation and its application Keita NAKAMURA, Satoshi MATSUMURA, Takaaki MIZUTANI
to behavior of open-ended pile driven into the ground

Japanese

June 2021

60-2-1Development of analytical method to detect position of
breakwater applying template-matching

Satoshi MATSUMURA, Takaaki MIZUTANI, Masaru SAKEI,Masatoshi SAKIMOTO, Hideyuki MATSUMURA, Eri TAKEUCHI

Japanese

September
2021

60-3-1

Numerical analysis on structural performance of deteriorated
open-type wharf with prestressed concrete superstructure

Yutaka TANAKA, Yuichiro KAWABATA, Ema KATO, Yoshikazu SUZUKA,
Shusaku KAWABE, Michio NAKAJIMA, Tsuyoshi ISHII,
Hisao TATEGAMI, Tetsuya OGASAWARA

Japanese

December
2021

60-3-2Analytical study on the bearing capacity of open-ended straight
Keita NAKAMURA, Satoshi MATSUMURA, Takaaki MIZUTANI
and tapered piles using MPM

Japanese

December
2021

Papers Published in PARI Technical Notes in FY 2021
No.

Title

LanguageMonth/Year

No.1385

Fundamental study on wave reduction effects by a wave power
generating floating breakwater

Haruo YONEYAMA, Hiroaki KASHIMA

Japanese

June 2021

No.1386

Annual Report on Strong-Motion Earthquake Records inJapanese Ports (2018)

Yosuke NAGASAKA, Atsushi NOZUJapanese

June 2021

Satoshi MATSUMURA, Takaaki MIZUTANI, Masaru SAKEIJapanese

September
2021

Effect of consolidation settlement on horizontal resistance of
No.1387
soft landing moundless structure with piles

Author(s)No.1388

Analysis of pile driving records in the Tobishima area of Nagoya
Port and consideration on construction management methods

Takaaki MIZUTANI, Satoshi MATSUMURA, Toru FUJITA,
Yasuhiro TAKEUCHI, Masaya KANI, Hiroyuki SAEGUSA, Yasushi KISHI

Japanese

September
2021

No.1389

Field measurement of seasonal variation in sediment transport
around the Patimban coast, Indonesia

Yasuyuki NAKAGAWA, Masayuki BANNO, Taichi KOSAKO,
Hitoshi TAMURA, A. Bagyo Widagdo, Dinar C. Istiyanto

Japanese

September
2021

No.1390

Construction of the prototype of underwater machine guidancesystem for an underwater excavator and accuracy verification

Tsukasa KITA, Taketsugu HIRABAYASHI, Shunsuke TAKAO,
Muneo YOSHIE

Japanese

September
2021

No.1391

Large-scale model test for the bearing capacity of open-ended
straight and tapered piles

Keita NAKAMURA, Yusuke MOTOMIZU, Satoshi MATSUMURA,
Takaaki MIZUTANI, Eiji OSHITA, Satoshi SHINGAI,
Yasutaka SAKAMOTO, Naoaki SUEMASA

Japanese

December
2021

No.1392

Study of maintenance for cathodic protection applied to marine
steel structures

Toru YAMAJI, Masayuki HARA, Ken-ichi NOTOYA,
Nobumitsu YAMANOBE, Yasuhiro TAKAHASHI, Shigenori KOBAYASHI,
Masaharu WATANABE

Japanese

December
2021

No.1393

Caisson joint wave reduction method for suppressing internal
erosion and collapse of seawalls and quaywalls

Shinji SASSA, Osamu ISHIZAKA

Japanese

December
2021

No.1394

Annual report on strong-motion earthquake records inJapanese ports (2019)

Yosuke NAGASAKA, Atsushi NOZUJapanese

December
2021

No.1395

Statistical analysis on parallel body lengths and wind receiving
areas of ships

Haruo YONEYAMA, Hiroaki KASHIMA

Japanese

December
2021

Tsukasa KITA, Taketsugu HIRABAYASHI, Shunsuke TAKAO,
Hiroshi KINJO, Naoki OSHIRO, Atsushi UEYAMA

Japanese

December
2021

Masao YAMADA

Japanese

March 2022

Japanese

March 2022

Sumire NAKAMURA, Yuichiro KAWABATA, Daisuke TATSUMIJapanese

March 2022

Ema KATO, Yutaka TANAKA, Yuichiro KAWABATA,
Tetsuya OGASAWARA, Hiroshi WATASE, Tsuyoshi ISHII,
Shusaku KAWABE, Akira MIYAZAWA, Yoshinao NAKAYAMA,
Michio NAKAJIMA, Hisao TATEGAMI, Nobuyuki YONEKURA,
Yoshiko AMEMIYA, Yoshikazu SUZUKA, Tatsuyuki FUJIMURA

Japanese

March 2022

Atsushi NOZU, Shuanglan WU, Yosuke NAGASAKA

Japanese

March 2022

Takahiro NISHIDA, Toru YAMAJI, Nagate HASHIMOTO,
Yoshiyuki KAWASE, Shinsuke SHIZURU, Takuya ICHINOSE,
Atsumi IMAI, Atsushi KOBAYASHI, Michio YOSHIDA

Japanese

March 2022

Proposal and performance test of attachment for realization
No.1396 of remote operation of rubble mound leveling work with
underwater backhoe
No.1397

Experiments on resistance of various wood materials against
marine borers and weathering

No.1398

Annual Report on Nationwide Ocean Wave Information Network
Koji KAWAGUCHI, Kanichiro YOSHIDA, Hitoshi TAMURA
for Ports and Harbours (NOWPHAS 2020)

Fundamental study on the calculation of CO2 emissions fromconstruction of port structures – Investigation on the preNo.1399
estimation method and trial calculation of CO2 emissions fromconstruction of port structures –No.1400

Guideline for maintenance and management of PC wharf
superstructure for port engineers

No.1401 A composite source model capable of generating fling steps
No.1402

Investigation for durability of corrosion prevention bypetrolatum lining

19 PARI Annual Report 2022

Outstanding Research Activities
Awards for Papers and Others in FY 2021
Name

Award

Institution

Date

Remarks

1

Tomohiro KUWAE Head, Coastal and Estuarine
Environment Group Coastal and Estuarine
Environment Department

Recycle Promotion Award

Recycle Solution (incorporated
non-profit organization)

May 25, 2021

Contribution to theenvironmental preservation
and restoration in shallow
coastal areas over theyears; and the quantitativeevaluation, raising of publicawareness, and popularizationof blue carbon.

2

Hidenori TAKAHASHI Head, Soil Stabilization Group
Geotechnical Engineering Department
Yoshiyuki MORIKAWA Director, GeotechnicalEngineering Department

JGS Research / Paper Award(English category)Japanese Geotechnical Society(JGS)

June 4, 2021

Collapse of concrete-covered
levee under composite effectof overflow and seepage

3

Yoshiyuki MORIKAWA Director, GeotechnicalEngineering Department
Takaaki MIZUTANI Head, Foundations Group
Geotechnical Engineering Department
Eiji KOHAMA Head, Earthquake and Structural
Dynamics Group Earthquake Disaster Prevention
Engineering Department
Satoshi MATSUMURA Senior Researcher,Foundations Group Geotechnical Engineering
Department

The Ports & Harbours
Association of Japan
Technology Award

The Ports & Harbours
Association of Japan(public interest incorporated
association)

June 9, 2021

Improvement of seismic
performance of sheet pile
quay walls by stabilizing the
ground between anchor piles

4

Tomohiro KUWAE Head, Coastal and Estuarine
Environment Group Coastal and Estuarine
Environment Department
Kenta WATANABE Senior Researcher, Coastal andEstuarine Environment Group Coastal and Estuarine
Environment Department
Toko TANAYA Senior Researcher, Coastal andEstuarine Environment Group Coastal and Estuarine
Environment Department

Japan Society of Civil
Engineers (JSCE)

June 11, 2021

Nationwide estimate of theannual uptake of atmosphericcarbon dioxide by shallow
coastal ecosystems in Japan

5

Yoshiyuki MORIKAWA Director, GeotechnicalEngineering Department

Continuing International
Contribution Award

Japan Society of Civil
Engineers

June 11, 2021

Contribution to thedevelopment of civilengineering and/or thedevelopment of infrastructure
outside Japan

6

Takahiro NISHIDA Senior Researcher, Materials
Group Structural Engineering Department

Engineering Encouragement
Special Award

Engineering Advancement
Association of Japan (generalincorporated foundation)

July 12, 2021

Development of novel
construction techniques fordesalinization, re-alkalization,and electro-deposition

October 15,
2021

Clarification and Estimationof Distribution Property of
Airborne Chloride Ion in Yoron
Island, Kagoshima

JSCE
Distinguished Paper Award

7

Kentaro KOIKE Senior Researcher, Materials Group
Structural Engineering Department

Excellent Paper Award

The Society of Materials
Science, Japan (JSMS)(public interest incorporated
association):
The 21st JSMS Symposium on
Concrete Structure Scenarios

8

Shinji SASSA Head, Soil Dynamics Group
Geotechnical Engineering Department
Soonbo YANG Postdoctoral Researcher, Soil
Dynamics Group Geotechnical Engineering
Department

Coastal Engineering Paper
Award

Japan Society of Civil
Engineers Coastal Engineering
Committee

October 18,
2021

Processes and the extent ofinfluence of internal erosion
under transmitted waves with
their countermeasure using a
two-layer filter

9

Hitoshi TAMURA Senior Researcher, Marine
Information Group Coastal and Ocean Development
Department
Koji KAWAGUCHI Head, Marine Information Group
Coastal and Ocean Development Department
Hiroaki KASHIMA Senior Researcher, Coastal andOcean Development Group Coastal and Ocean
Development Department

Coastal Engineering Paper
Award

Japan Society of Civil
Engineers Coastal Engineering
Committee

November 10,
2021

Wave force at the Port of
Yokohama due to Typhoon
Faxai in 201910

Kazuki MURATA Researcher, Soil Dynamics Group
Geotechnical Engineering Department

JACZS
Research Symposium
Excellent Lecture Award

Japanese Association for
Coastal Zone Studies (JACZS)

November 11,
2021

11

Toru YAMAJI Director, Structural Engineering
Department Head, Materials Group

AI & Data Science
Encouragement Award

Japan Society of Civil
Engineers

November 30,
2021

12

5th Infrastructure MaintenanceGrand Prize, Technological
Development Category, Special
Award

Ministry of Land

January 21,
2022

Safety and quality
improvement related tothe maintenance andmanagement of piers using
replaceable slabs

Shuji NOGAMI Senior Researcher, Meta-Robotics
Group Infrastructure Digital Transformation
13 Engineering Department
Ema KATO Principal Researcher Infrastructure
Digital Transformation Engineering Department

Best Paper Awards on
Infrastructure MaintenanceJapan Society of Civil
Engineers Committee on
Infrastructure MaintenanceMarch 14, 2022

A feasibility study of anunderwater drone for visualinspection of port structures

PARI Annual Report 2022 20

The Open Institute
Annual Report, Technical Journals, andHP“The Annual Report 2021” (Japaneseversion) and “The PARI Annual Report2021” (English version), which concisely summarized our activities in FY
2020, were prepared as a record of ourachievements and distributed to the related institutions and posted on PARI HP.
Regarding “The PARI Technical Journal”, we selected special articles of eachresearch theme for every issue to introduce utilization situations of research
results and PARI’s experiment and onsite observation facilities. Approximately
2,000 copies of “The PARI Technical
Journal” are distributing to approximately 1,600 places.
The PARI Technical Journal
On HP, we provided various information on events and news including
our institute summarized information, results, facilities, symposiums on areal time basis; we got approximately 130,000 accesses in FY 2021.

Institute Facility Open to the Public
Open to the Public
The FY2021 facility open house has been cancelled due to the expansion status of the COVID-19. Instead, videos were posted on the
National Institute of Maritime, Port and Aviation Technology (MPAT)
website as a virtual open house, and also an online open experiment
was conducted on February 15, 2022 (involving recreation of quaywall-overtopping waves and inundation resulting from high waves during storm surges). This open experiment, the first of its kind offered by
PARI, was attended by 288 individuals, many of whom were elementary
school students and others affiliated with educational institutions.

Camera image overlooking the entire
experimental water tank

Implementation of lectures for the General Public
Port and Airport Technology Lecture
In cooperation with the National Institute for Land and InfrastructureManagement (NILIM), a web-based lecture on port and airport technology was held on January 31, 2022 for the purpose of publicizing
and disseminating the results of surveys, research and technologicaldevelopment conducted by PARI. The lecture event in FY 2021, which
was entitled “Achievement of Carbon Neutrality and a Carbon-Free Society by 2050,” included special lectures given by speakers invited fromprivate enterprises as well as presentations delivered by various PARI
and NILIM researchers on their research results, and was attended by
250 individuals.

Images from a fixed camera at thebottom of the experimental water tankOpen experiment (web-based) in progress

Other Outreach Activities
Cooperation with Super Science High school (SSH) Projects
For students of Kanagawa Prefectural Yokosuka High School is designated as an SSH school by the Ministry of Education, Culture, Sports,
Science and Technology, we provided guidance on the preparation ofresearch projects and conducted tours of the institute's facilities, in order to encourage students' interest in the institute.

Web-based lecture

Port and Airport Technology Special Regional Lecture
In cooperation with the National Institute for Land and InfrastructureManagement (NILIM), Regional Development Bureaus and other organizations, the web-based seminars were held in four regions across Japan, each of which had more than 100 attendees and for approximately
440 attendees in total, for the purpose of providing wide-ranging information on the Institutes’ research activities and results, and gathering
information on research needs in each region.

21 PARI Annual Report 2022

Students listening to a researcher’s lecture

PARI Events
Active participation in International Conferences,
Workshops, and etc.
Following the establishment of November 5, Japan's Tsunami Disaster Prevention Day, as “World Tsunami Awareness Day” at the United
Nations General Assembly in December 2015, the Goryo HAMAGUCHIInternational Prize (Minister of Land, Infrastructure, Transport and Tourism Prize) was established in 2016 for those who have made outstanding achievements in the field of coastal disaster prevention technology,
including tsunami disaster prevention. The award was presented on
November 29, 2021 to two persons and one organization: Dr. Hideo
MATSUTOMI (Professor Emeritus at Akita University and Visiting Professor at Chuo University’s Research and Development Initiative); Dr.
Gerassimos A. PAPADOPOULOS (Chairman, International Society for
the Prevention and Mitigation of Natural Hazards (ISPMNH)); and thePacific Tsunami Museum (Hawaii, USA).

the needs of affected areas by swiftly dispatching its researchers to thedisaster sites. Examples of such dispatches include on-site investigation of the drifting pumice that resulted from the eruption of the submarine volcano Fukutoku-Okanoba in November (Okinawa Prefecture) andport disaster assessment following the earthquakes that occurred off thecoast of Fukushima Prefecture in March 2022 (Fukushima Prefecture andMiyagi Prefecture), as part of the joint investigation teams organized with
the National Institute for Land and Infrastructure Management (NILIM).

On-site investigation of drifting pumice

A prize awarding ceremony and commemorative lecture of the
Goryo Hamaguchi Award (November 29, 2021, Tokyo)

PARI held a joint research workshop with Indonesia’s Badan Pengkajian
dan Penerapan Teknologi (BPPT; Agency for the Assessment and Application of Technology) in April 2021.
In addition, PARI hosted and chaired a meeting of the International Society for Soil Mechanics and Geotechnical Engineering’s Technical Committees in October 2021, which was attended by a total of 32 Committee
members from 14 countries and saw active technical exchanges among
researchers representing PARI and other overseas research institutes.

Wide Range of Exchanges with Domestic andOverseas Research Institutes
In order to further improve the quality and efficiency of our research,
we have been actively promoting collaboration with domestic and overseas research institutions, and as of FY2021, we have concluded a totalof 56 research cooperation agreements: 29 in Japan and 27 overseas.

Conclusion of Education and Research Cooperation
Agreements
Based on the "Cooperative Graduate School System," in which
the institute and national, public, and private universities conclude anagreement and researchers from the institute become professors at
graduate schools and supervise graduate students in research books,
etc., the institute has concluded cooperative agreements with 13 universities including Tokyo Institute of Technology, Nagoya University, andNagaoka University of Technology.
In FY2021, we dispatched 15 lecturers. In addition to the cooperative
graduate school system, a total of five lecturers were dispatched to the
Nagoya Institute of Technology, etc.

Promotion of Administrative Support
Dispatch of researchers to disaster-affected sites
In FY 2021, PARI conducted on-site surveys in the Izusan area of
Atami City in July in response to the disaster caused by debris flows,in conjunction with the MLIT’s Ports and Harbours Bureau, etc. In addition, PARI continuously contributed to disaster recovery efforts based on

Disaster assessment at Soma Port

Dispatching of members to Various Technical Committees, etc.
A total of 164 researchers were dispatched to serve as members ofvarious technical committees held by the national and local governments to solve technical problems related to the implementation of
public works such as ports, coasts, and airports.
In addition, if we include the technical committees established byvarious institutions for port, coastal and airport development and airport
maintenance, we have dispatched a total of 410 members, who have
responded energetically to solve technical problems faced by the government and other organizations.
Support for Operations related to Technical Standards for Portsand Harbors
With regard to technical standards for port facilities, we have cooperated by participating as a member of committees established by thePort and Harbor Bureaus of the Ministry of Land, Infrastructure, Transport and Tourism. We also cooperated in the dissemination of technical standards at workshops held by the National Institute for Land andInfrastructure Management, academic societies, and related organizations. As for airport facilities, we cooperated with various study committees for the smooth dissemination and operation of technical standards
for airport civil engineering facilities.
Support for the Evaluation of New Technologies
At the request of the Ministry of Land, Infrastructure, Transport andTourism (including regional development bureaus, etc.), we dispatchedresearchers to the "Evaluation Council for New Technologies" established by each organization to evaluate the applicability of technologies
registered in the "New Technology Application System for Public Works,etc. (commonly known as NETIS)" to the field in order to promote theuse of useful new technologies, and provided technical support.

PARI Annual Report 2022 22

National Institute of Maritime, Port and Aviation Technology

Port and Airport Research Institute3-1-1 Nagase, Yokosuka, Kanagawa 239-0826, JAPANTEL +81-46-844-5040 FAX +81-46-844-5072
URL https://www.pari.go.jp
Annual Report 2022 July 2022
この印刷製品は、環境に配慮した資材と工場で製造されています。