Using New Technology in Disaster Risk Reduction: Particle Method Analysis
New technology: Particle methods
Particle methods are numerical analysis methods that simulate the behavior of continuous masses by modeling all substance s—i ncl udi ng fluids—a s
continuous masses of particles. We at NEWJEC have engaged in joint research with Professor Hitoshi Gotoh of the Kyoto University Graduate School
to use particle methods in various examinations of phenome na associated with severe deformati on that cannot be simulate d using general partic l emethods (e.g. the finite element method). We are also leveraging our know-how of particle methods to develop an evacuation simulation model for
analyzing crowd evacuation behavior with individual people as constitue nt elements.

Case example 1: Tsunami causes breakwater damage
Particle methods

are numeric alanalysis

methods

Case example 2: Evacuation simulationthat simulate

theRapid, smooth evacuation is the key to survival

for people living andbehavior of continuous masses by modeling all substance s—i ncl u di ng

working in coastal areas when tsunami are approac hi ng. Therefore, it isfluids—as continuous masses of particles. We at NEWJEC have engag e dimportant to ensure proper evacuation routes and stairways as well as

in joint research with Professor Hitoshi Gotoh of the Kyoto Universi ty

evacuation areas. Unfortunately, evacuation drills and other efforts tak e n

Graduateduring normal times rarely replicate the urgency with which people must

School to use particle methods in various examinati ons ofphenome na

associate dwithsevere

deformation

thatcannot

beevacuate during disasters.

[文書の重要な部分を引用して読者の注意を引いたり、このスペースを使って注目ポイントを強調したりしま
evacuation simulation model for analyzing crowd evacuation behav i orしょう。このテキスト ボックスは、ドラッグしてペー
withindividual people as constitue nt elements.
ジ上の好きな場所に配置できます。]
simulated using general particle methods (e.g. the finite element method ) .

We are also leveraging our know-how of particle methods to develop anSTEP1
CaissonFoundati on

Simulationofa
caisson slipping into
scour caused by the
overflow mass eroding
the foundation moundover time
Evacuation simulation in a
virtual coastal industrial area
(Evacuation areasrepresented by yellow dots)

STEP2
Overflow

STEP3

Scour

Accordingly,evacuation

simulations

evacuation behavior unfolds

that realistically depict how crowd

in a virtual environme nt

are an effecti v emeans of replicating the urgency. This method goes beyond setting out
appropriate evacuation routes and areas, and it should help residents learn
to visualize what to do when a tsunami approac he s.

Demonstration of the effects ofcountermeasures (e.g. breakwater widening)
Using riprap or the like behind breakwaters to effectively widenthem demonstrably limits caisson slippage and scour caused by
overflow mass.
Raised crown

Ascertaining the time required for evacuation
Those from which it takes the most time to reach evacuation areas.

Particle method-based tsunami-resistance analysis for breakwaters(simulating damage, demonstrating the effects of countermeasures)
Introduction
The damage to a breakwate r north of the Hattaro district of Hachinohe Port is a typical example of the damage caused by the tsunami triggered by
the 2011 Tohoku Earthquake. Althoug h the breakwate r caissons withstood the tsunami wave force, they slipped down into scour that occurred whe noverflow from the tsunami eroded the foundation mound. This type of damage was not envisione d, and it is difficult to confirm the safety of the caissons
with only a conventional stability compari son.
We at NEWJEC are developing technology (with Professor Hitoshi Gotoh of the Departme nt of Civil and Earth Resources Engineering of the Kyoto
University Graduate School of Engineering) in which the use of particle methods makes it possible to simulate damage to breakwater caissons anddemonstrate the effects of countermeasure s.
P rogression of scour caused by tsunami
overflow eroding the foundation mound
Overflow causes
scour to progress

P rogression of scour caused by tsunami
overflow eroding the foundation moundDestabilized caisson mov es
due to the increa se ddifferences in water level
Wave dissipating block s The scour of the foundation mou n dcollapse toward the port destabilizes the breakwater caisso n s
after the caisson slips
and degrades their bearing capacity
Source: Materials from the Third Advisor y Panel for Tsuna mifor Ports and Harbors in Tohoku

and Earthqua ke Count er mea sur e

E xample of damage to a breakwater (reconnaissance survey of Miyako/K uji)Techn o lo g yDamage to a breakwater north of the H attaro district of H achinohe P ort■ Characteristics of particle method-based analysis
・Enables visualization of splitting and merging of waves caused by waves breaking and complex motion phenomena of sand andstructures.
・Enables determination of physical quantities (e.g. wave pressure, overflow volume, structure movement) required for designconditions.
・With no computational grid as in the case of finite difference and finite element methods, enables the processing of phenomena
involving severe deformation.

【Simulation results】【Hydraulic model experiment results】
We

ranhappens

a simulation
whento seea wavewhat

breaks andflows over an embank me nt with one
open

end

facingthewave

anda

protrusi on on the top.
Compare dto

thehydraulicexperime nt,

thesimulation

mode lproduc e dbetter reproduc tions of the phenome n a
and yielded precise overflow
calculation

resultsexperime ntal values.

amountcompare dto