●Research Trends and Results

Development of the practical sand pack work method
SUWA Yoshio, HeadNOGUCHI Kenji, Senior Researcher
WATANABE Kunihiro (Dr.), Researcher
SEKIGUCHI Yoko, Exchange Researcher
River Department, Coast Division(Key words) Civil engineering use fibers, beach materials, beach nourishment
1. Definition of the sand pack work method
The sand pack work method is filling large clothbags made of civil engineering use fibers with sand,which is field test ocean beach material and beachnourishment material. Research on this method began
in response to a growing public demand for easilyremovable structures to replace concrete structures andfor the reduction of overall project costs. To be used
as a method to replace various kinds of shoreline
structures, problems related to structural stability,workability, and durability must be solved.
This research has been carried out since the autumn
of 2010 jointly by three private sector
civil-engineering use fiber material makers, as“Research on technologies to evaluate theperformance of sand-bag filling work for shoreline
conservation.”

Specimen N
Specimen MC

Beach scarp
topFall 2010

Specimen MD

BeachnourishmenttiHeight of one sandpack level: 1.5m

Photo 1. Sand Pack Field Experiment on theSumiyoshi Shoreline
method to lower the loss of beach nourishment
materials as shown in Photo 1 and then the site wasmonitored for one year, confirming its effectivenessand stability under rough waves. As a result of
installing sand packs on the sandy ground in this way,
the ground was deformed by localized erosion of theground surface. Figure 3 shows the test performed toinvestigate the tensile force acting during deformation.
Through these efforts, the practical application stage
has been reached. We wish to systematize and provide
the results in usable form as the Sand Pack Work
Method Handbook (Draft). Information about thisresearch is available on the web site of the Coast
Division (http://www.nilim.go.jp/lab/fcg/).

2. Efforts to realize the method
As shown in Figure 1, shorelines where the externalforce (waves, weather) differ were selected as the sites
for field tests and exposure tests, while stability andmaterial properties were tested in a laboratory. Figure
2 shows the locations of the shorelines where theexposure tests and execution tests were performed.
Beginning in the middle of March in 2012, on theSumiyoshi Shoreline in Miyazaki Prefecture, sandpacks were placed and tested as a supplementary
Field experiment

The sand pack is covered withbeach nourishment material toa thickness of 1m

Test etc.

Start of joint research
Study of the rotating drum typewear test

Installing specimen for preliminary test of shoreline erosion
countermeasure facility on Irabushima Island in Miyakojima
City in Okinawa Prefecture (MD)Pier type construction test
(Kanagawa Pref., Oisoshoreline)
Withstands highwaves (Dec. 31,2010)
Great East Japan
Earthquake

Start of pack material exposure test
(South Sendai Harbor, Shimonii River,Urahara, Irabu)
Hydraulic model test of stability in a case of
application to shoreline protection facility

Pack material exposure test
Shimonii river shoreline
Pack material exposure test
Chirihama Beach shoreline
Field execution test

2011

Trial execution in front of beach scarp
on the Hamaju Coast of Fukui
Prefecture

Model test of tensile force acting onpack material during sand packdeformation (large, hydraulic, small)

Oiso shoreline trial removal (Jointwork by 3 companies)

Study of comparative test of wear specified
for beach shoreline

Request for 1,000 sandpacks (Ishikawa
Prefecture, Chirihama
Beach Event)‧ Development of colored materials withstrengthened wear resistance whileconsidering scenery‧ Development of sand pack structure withimproved workability(Three companies: N, MD, MC)2012
Trial sandy beach execution below
tide level (Chirihama Coast, Ishikawa
Prefecture: MD)

Start of test to verify the scarp failure
prevention work on Miyazaki Beachmanaged by Miyagi Prefecture (NILIM
and 3 companies N, MD, MC)

Field execution test

Hamaju Shoreline (Fukui City)
Field pump filling test

South shore of Sendai Harbor
Pack material exposure test

Oiso shoreline
Field execution test
Urahara shoreline
Pack material exposure test

Shoreline (Irabujima Island)
Field installation test and pack material exposure test

Figure 1. Chronology of the Courseof the Research

Bends if the sea
bottom groundis lowered byerosionSumiyoshi shoreline
Field installation test

Test of fiber damage mechanisms bycause of damage
Start of study of new maintenance method
using sand packs (man-made bar)Tensile force acts
around here

Figure 2. Shorelines where Pack
Material Exposure Tests and Field
Tests were Performed

It is necessary to design fiber strength
considering deformation time

Figure 3. Model Test ofTensile Force Acting During
Deformation Caused byErosion