Geosynthetics Engineering Journal
Online ISSN : 1883-146X
Print ISSN : 1344-6193
ISSN-L : 1344-6193
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Showing 1-31 articles out of 31 articles from the selected issue
Papers
  • Ryohei Ishikura, Noriyuki Yasufuku, Yoshihiro YOKOTA, Shinichiro TSUJI
    Type: Paper
    2020 Volume 35 Pages 1-6
    Published: 2020
    Released: December 06, 2020
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    There is a mattress reinforcement method applied as a countermeasure for soft ground. The authors propose a new type of structure in which large sandbags are installed at both ends of the mattresses just below the embankment to further improve the bearing capacity of this method. In this paper, the effect of the wall-type protrusions on the both ends of the mattresses to improve the bearing capacity of the mattresses was investigated by using a series of load tests with aluminum bars. In recent years, the application of mattress reinforcing method is required for narrow land, and the method to determine the optimal mattress width for the loading width is an important issue. Therefore, a series of model experiments focusing on the relationship between loading width and mattress width were also conducted using the same loading tests. Based on the experimental results, a method for determining the optimal loading width for a given width of mattresses, which can be expected to improve the bearing capacity, was studied.
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  • Koichi Yamanaka, Kunio Minegishi, Ryo Hashimoto
    Type: Paper
    2020 Volume 35 Pages 7-14
    Published: 2020
    Released: December 06, 2020
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    Due to its expected such as increase in bearing capacity obtained by restraining geomaterial to be filled in the cell and stress dispersion effect by the geocell formed in a plate, construction method based on geocell has been considering for various applications in recent years. However, Reinforcement effect of geocell, differs depending on the material condition of geocell (such as cell height and area). It is important to figure out influence of material conditions of geocell on reinforcement effect and its degree of impacts in order to review design methods too. Therefore, degree of impacts of each material condition on reinforcement effect has been discussed in the current study from results obtained an indoor loading test by preparing model grounds with varied geocell height, cell area and developed area.
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  • Masahiro Shinoda, Taiki Takakura, Yoshihisa Miyata
    Type: Paper
    2020 Volume 35 Pages 15-22
    Published: 2020
    Released: December 06, 2020
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    Many shaking table tests were carried out to investigate seismic performance of retaining walls, but there are few examples of shaking table tests focusing on resilience performance of the retaining walls. In this study, a long-term shaking table test of unreinforced and reinforced soil retaining walls was conducted to compare the resilience performance. From the test results, it can be confirmed that the unreinforced retaining wall collapsed with a relatively small excitation energy due to the ground yielding, but the reinforced soil retaining wall did not collapse even when a relatively large excitation energy was applied, and showed high resilience performance.
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  • Masaki Koyama, Shunzo Kawajiri, Yuki Kurakami, Taisuke Sanagawa, Teruy ...
    Type: Paper
    2020 Volume 35 Pages 23-28
    Published: 2020
    Released: December 06, 2020
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    In recent years, erosion and runoff damage have occurred in the back embankment of the abutment of conventional type railway bridge due to the increase in flood magnitude. However, the basic mechanism of erosion and runoff process of railway embankment is not clear. In this research, we made a back embankment of a model abutment that reproduced the old type railway abutment and conducted an open channel test. As a result, when the RRR-B method was used to strengthen and restore the wing wall and the back of the girder, the erosion inside the embankment and the collapse of the embankment slope were prevented by the geogrid installed inside the embankment.
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  • KAITO TSUCHIYA, MICHIO IBA, HIROFUMI NAKAYAMA, TAKAYUKI SHIMAOKA
    Type: Paper
    2020 Volume 35 Pages 29-36
    Published: 2020
    Released: December 06, 2020
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    In this study, the author took geomembrane samples from 3 conditions (exposed to sunlight, exposed under protection mat, buried in waste) in landfills and evaluated each degradation progress by microscopy, roughness measurement on surface, tensile test and so on. The result showed that geomembrane samples under protection mat and buried in waste had less cracks on surface and retain initial mechanical performance compared to those exposed to sunlight. In temperature measurement on surface, there were big difference in temperature changes with or without protection ma and the total amount of solar radiation considering that had a negative correlation with mechanical properties.
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  • Shuang LIU, Takayuki KAWAGUCHI, Shunzo KAWAJIRI, Dai NAKAMURA, Akinobu ...
    Type: Paper
    2020 Volume 35 Pages 37-44
    Published: 2020
    Released: December 06, 2020
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    As a measure against frost heaving of reinforced soil wall, setting an anti-freezing layer or insulation behind wall facing is recommended in design guidelines and manuals nowadays. However, the reinforced soil walls which were built before the guidelines decided, are difficult to evaluate the risk of deformation caused by frost heaving of geomaterial. In this research, a new model test system has been developed which can measure the strain on reinforcement material caused by frost heaving. As a result, it was found that the strain on reinforcement material is changed by the vertical stress on reinforcement material, the frost heaving property of geomaterial and the frozen region around the reinforcement material.
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  • Ko HASHIMOTO, Takuya SUMIYAMA, Kenji FURUICHI, Yoshinori YOKOYAMA, Mas ...
    Type: Paper
    2020 Volume 35 Pages 45-52
    Published: 2020
    Released: December 06, 2020
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    Geomembrane sandwiched by non-woven fabric is laid on the slope of a coastal waste disposal site, and crushed stones (D ≦ 60 mm) are used to form the smoother slope surface over the backfill stones. However,crushed stones may be scoured by waves, and the sheet cannot be laid as designed. It is now being considered to lay a 5-layer sheet on the rubbles instead of crushed stones. In this study, the puncture resistance of a 5-layer sheet was examined using penetration tests and FEM analysis. Further, the pressure receiving tendency of the 5-layer sheet loaded with rubbles was estimated from laboratory experiment and site investigation.
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  • Takumi Kitamura, Kenichi Sato, Takuro Fujikawa, Chikashi Koga, Yuichir ...
    Type: Paper
    2020 Volume 35 Pages 53-58
    Published: 2020
    Released: December 06, 2020
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    With the age of asphalt pavement, the service function of asphalt pavement is degraded by cracking,rutting and roughness. In particular, the reduction in bearing capacity of the base course due to rainwater infiltration from cracks has a significant impact. On the other hand, asphalt pavement is required to maintain its function for a long period of time and to reduce management costs. In this study, geotextiles were installed in the base course to improve the bearing capacity of asphalt pavement and to investigate countermeasures against rainwater infiltration by cracks. In this paper, the effect of rainwater infiltration on the bearing capacity and deformation of geotextile-loaded ground is investigated by conducting loading tests in a small soil box. The results showed that the reduction in the bearing capacity of the base course with rainwater infiltration was suppressed by laying geotextile, which was effective in improving the durability of the pavement.
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  • Takashi Katayama, Kazumasa Kusudo, Ken-ichi Kojima, Naoyuki Yaguchi, S ...
    Type: Paper
    2020 Volume 35 Pages 59-66
    Published: 2020
    Released: December 06, 2020
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    The chemical adhesive waterproof sheeting is applied to waterproofing of underground structures such as tunnels. Since the waterproof sheeting has high adhesiveness to concrete, the crack-bridging tension may occur at crack opening region. In this study,the water pressure resistance of the waterproof sheeting under the crack-bridging tension was examined by finite element analysis.It showed that the waterproof sheeting will not break in 5mm of crack opening under 1.5MPa of high water pressure like former experiment results. And the deformation behavior to breaking of the waterproof sheeting was also expressed by finite element analysis.
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  • Shintaro Miyamoto, Yoshihisa Miyata
    Type: Paper
    2020 Volume 35 Pages 67-74
    Published: 2020
    Released: December 06, 2020
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    To investigate the effects of the reinforcement content on the mechanical behavior of short fiber-reinforced soil, direct shear tests were performed on the specimens wherein the reinforcing materials were arranged vertically. In the series of tests, a shear box test apparatus with a transparent acrylic side plate was used to visualize the internal behavior of the soil and reinforcement. If the reinforcements were sparsely arranged, they were pulled out, and the specimen reached the failure state. The peak strength of the specimen was proportional to the reinforcement content. If the reinforcements were densely arranged, the soil and reinforcements behaved integrally, and the specimen did not reach the failure state. It was also observed that there is a limit to increase the shear resistance by the reinforcement content.
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  • Kyungbeom Jeong, Jemin Baek, Satoru Shibuya, Tomoko Urabe, Masatoshi I ...
    Type: Paper
    2020 Volume 35 Pages 75-80
    Published: 2020
    Released: December 06, 2020
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    In this paper, aseismicity of an earth-fill dam after when repaired with geosynthetic clay liner to prevent water leakage, and to improve the seismic performance, was evaluated. First, the factor of safety against the earth-fill dam failure was calculated by using pseudo-static limit equilibrium analysis under the Level 1 earthquake conditions. Second, the seismic response characteristics of the earth-fill dam was examined using time history 2D seismic response analysis during the occurrence of level 2 earthquake. The results show that both of the safety factor and the residual crest settlement on the small earth-fill dam satisfy the relevant design standard.
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  • Tatsunari FURUYA, Takayuki KAWAGUCHI, Dai NAKAMURA, Shunzo KAWAJIRI, T ...
    Type: Paper
    2020 Volume 35 Pages 81-88
    Published: 2020
    Released: December 06, 2020
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    In this study, water sprinkling tests were carried out on a model slope constructed in a laboratory for the purpose of quantitatively evaluating the seepage control effect of a slope protection work composed of two layers of geocell with different filling geomaterials. In this protection work, it is expected that the seepage of rainwater and snowmelt water will be controlled by putting non-woven fabric and the geocell filled with sandy soil on the geocell filled with crushed stone. As a result, it was clarified that when the amount of water sprinkled was about 55 mm/h, only about 30% of the total amount of collected water permeated the model embankment, and that the amount of permeated water is further reduced by replacing filling geomaterial around the toe of slope to crushed stone.
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  • Yoshihiro Yokota, Shinichiro Tuji, Takayoshi Wada, Keisuke Kojima
    Type: Paper
    2020 Volume 35 Pages 89-94
    Published: 2020
    Released: December 06, 2020
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    Shaking table test under gravity field and residual deformation analysis were carried out for reinforced embankment on liquefied ground. We compare the effect of the case of reinforcing mattresses with geotextile wrapped crushed stone and the case of sandbags installed at both ends of the mattress in order to mitigate liquid damage. The results show that when large sandbags are placed at both ends of the mattress, the effect is almost the same as in the case of thicker mattresses, and the amount of crushed stone can be reduced to reduce the cost.
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  • Takahiko KATO, Satoru SHIBUYA, Satsuki KATAOKA, Hirosi NAKAZAWA, Noria ...
    Type: Paper
    2020 Volume 35 Pages 95-102
    Published: 2020
    Released: December 06, 2020
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    The authors have proposed an aseismic reinforcement at the toe of embankment using soil-bag structure. In the past study, the performance was examined in a large-scale shaking table test using a model embankment with 4m high. As a result, the soil-bag structure was found effective in terms of reducing the response acceleration in the embankment to some extent. However, it was also found that the structure was not robust enough by exhibiting shear deformation during shaking. Accordingly, the prestress required to increase the confining pressure was investigated in a shaking test of the soil-bag structure. Moreover, direct box shear test was carried out in order to manifest the characteristics of the soil-bag to soil-bag friction. In this paper, based on these experimental results, design method of the aseismic reinforcement at the toe of embankment using soil-bag structure are presented.
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  • Hiroyuki Kyokawa, Zain Maqsood, Junichi Koseki
    Type: Paper
    2020 Volume 35 Pages 103-108
    Published: 2020
    Released: December 06, 2020
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    The recoverability of an expanded polymeric bead foam is important to consider the mechanical property of the lightweight embankment using such foam which has been damaged due to an earthquake. In this study, the strength and deformation characteristics of the expanded polypropylene (EPP) block, which has a higher energy adsorption and recoverability, are investigated by a series of uniaxial compression tests with various strain rates, strain histories and the creep times after unloading. It could be observed from experiment results that the EPP block shows an elastoviscoplastic behavior, and the residual strain after unloading path decreases with time and the stiffness recovers simultaneously.
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  • Pradeep POKHREL, Jiro Kuwano, Taichi Iyo, Yu Hirano
    Type: Paper
    2020 Volume 35 Pages 109-114
    Published: 2020
    Released: December 06, 2020
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    In recent years, collapse of a sinkhole or a hidden cavity is widely observed in the road pavement of the urban city. The number of underground cavities in the road pavement in Tokyo Bay area of Japan increased after the 2011 Tohoku earthquake. In this study, a series of shaking table tests was carried out to investigate the stability of subsurface cavity subjected to seismic motion. Model ground was prepared with and without using geosynthetic materials to understand the effect of geosynthetics on seismic stability of the subsurface cavity. A subsurface cavity was formed above the opening at the base of a soil chamber by supplying and draining water. In addition, different drain condition of the model ground was applied to simulate the possible water tables. It was observed that the surface settlement of the model ground is highly affected by the remained water level. In addition, the stability of the subsurface cavity having geosynthetic material was increased by the load transfer effect of geosynthetic material.
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  • Kamal Prasad REGMI, Jiro Kuwano, Taiki Yamato
    Type: Paper
    2020 Volume 35 Pages 115-120
    Published: 2020
    Released: December 06, 2020
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    Road cave-ins have become more frequent all over the world. Cave -in process is generally due to the formation and propagation of the subsurface cavity. Nowadays, geosynthetics materials are used to stabilize the soil. In this study, laboratory model tests were conducted to study the stability of the subsurface cavity with and without geogrid reinforcement. A circular subsurface cavity of variable diameters was formed inside the model base course and a static loading was applied on the surface. Test results revealed that the reinforced cavities have become more stable on surface loading. Unreinforced cavities were collapsed suddenly at a certain point of load amplitude. However, surface deformation was increasing gradually with an increase of load amplitude in reinforced cavities. The wide reinforced cavity has more surface deformation while the narrow cavity has less at maximum given load of 1000 kPa. The width of the cavity has influenced its stability.
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  • Hiyori MATSUMOTO, Takayuki KAWAGUCHI, Shunzo KAWAJIRI, Masaharu TATEBA ...
    Type: Paper
    2020 Volume 35 Pages 121-128
    Published: 2020
    Released: December 06, 2020
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    There are use of inadequate embankment materials and insufficient compaction as factors which cause the reinforced soil wall to change shape. Such a situation is caused by a change in the borrow pit or a sudden change in soil properties due to rainfall. However, current quality control methods are likely to overlook this change. In this study, therefore, we tried to construct a quality control system that can check embankment materials frequently by storing the torque when turnbuckles of anchor reinforced soil walls are rotated in the cloud storage, and can confirm measured values in real time even by people who are not in the construction site.
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  • Hideto Nonoyama, Yoshihisa Miyata, Kazuma Fukumoto
    Type: Paper
    2020 Volume 35 Pages 129-134
    Published: 2020
    Released: December 06, 2020
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    To investigate the bearing capacity mechanism of a geogrid-reinforced foundation, the physical modeling technique of visualization using transparent soil was examined. Quartz glass and mixed mineral oil were used for the transparent soil. A polyethylene net was used for the geogrid. The movements of the soil and the geogrid under a strip loading were captured using camera and analyzed through particle tracking velocimetry. The developed system was validated for the visualization of soil and geogrid deformation under loading on both unreinforced and reinforced foundations. Based on the experimental results, an analysis method that could evaluate the reinforcement effects of the geogrid on the overburden effect was investigated. It was clarified that the proposed analytical formula can calculate an ultimate load and that considering of geogrid tension effect and rigidity of geogrid should be considered to predict it with higher accuracy.
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  • HIROYUKI ISHIMORI, TAKAYUKI HONJO, MIKAKO NAKAGAWA, TOMONORI ISHIGAKI, ...
    Type: Paper
    2020 Volume 35 Pages 135-140
    Published: 2020
    Released: December 06, 2020
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    In recent years, the environmental safety for organic compounds with high molecular weight and hydrophilic properties, such as bisphenol A, 1,4-dioxane, and persistent organic pollutants (POPs), has been of concern. This paperintroduces a conceptual model of the barrier performance of geomembranes against such organic compounds. The pore diameter, which is one of the barrier performance, was estimated from the viewpoint of molecular dynamics. By solving the equation of motion with Brownian motion, fluid force,and intermolecular force acting on each molecule as external forces, the relationship between the pore size and the diffusion coefficient in the geomembrane was evaluated.
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  • Atsushi Koyama, Daisuke Suetsugu, Yoshinori Fukubayashi, Hitoshi Mitab ...
    Type: Paper
    2020 Volume 35 Pages 141-148
    Published: 2020
    Released: December 06, 2020
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    A method for renovating a deteriorated bridge as a lightweight embankment was proposed. However, it is possible that a polyurethane foam separate from sufface of bridge member due to the holizontal force by earthquake. In this research, a series of direct shear box tests were conducted to evaluate the adhesive strength of polyurethane foam. Therefore, the interface shear strength between polyurethane foam and concrete plate as well as shear strength of polyurethane foam were carried out. As a result, The polyurethane foam was compressed by the inside of upper shear box during shearing and peeled off from the concrete plate when shear displacement reached approximately 30mm. The shear strength of the interface between polyurethane foam and concrete was affected by normal stress.
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  • Koshiro Matsushita, Shunzo Kawajiri, Hijiri HASHIMOTO, Akinobu OGASAWA ...
    Type: Paper
    2020 Volume 35 Pages 149-156
    Published: 2020
    Released: December 06, 2020
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    In the case of deformation of the reinforced soil wall, it was pointed out that the content of fine grains in the backfill material was high and that the backfill material was fine-grained in the survey conducted after the transformation. However, there are no cases in which the effects of the physical properties and compaction degree of the embankment material on the mechanical behavior of the reinforced soil wall were examined in a full-scale reinforced soil wall. In this study, we constructed a full-scale reinforced soil wall using three backfill materials and observed the mechanical behavior of the reinforced soil wall. As a result, the displacement of the wall panel and the tensile strain of the reinforcement were related to the amount of fine particle content.
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  • MICHIO IBA, KAITO TSUTIYA, HIROFUMI NAKAYAMA, TAKAYUKI SHIMAOKA
    Type: Report
    2020 Volume 35 Pages 157-162
    Published: 2020
    Released: December 06, 2020
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    "Handbook of Durability Evaluation of Geomembrane at Landfill" was published by the Geomembrane Technical Committee of the Japan Chapter of the IGS (or GM Technical Committee) in 2009. At that time, we collected 66 sample pieces aged 14.8 years in average from 7 landfill sites. In the 11th stage of GM Technical Committee started in 2018, we collected 55 pieces with average 23.5 years from 10 landfills to sample long aged geomembrane. In this paper, we report the data and the analysis result of collected pieces.
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  • - SOIL RETAINING STRUCTURES FOR HAGA-USTUNOMIYA LRT PROJECT -
    Teppei Omata, Masahiro Okamoto, Makoto Yasuno
    Type: Paper
    2020 Volume 35 Pages 163-170
    Published: 2020
    Released: December 06, 2020
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    The construction of geotextile-reinforced soil (GRS) retaining wall having full-height rigid facing by RRR-B method is briefly explained, followed by the outline of the new Light Rail Transit project between Haga and Utsunomiya in Tochigi Pref. Japan. This is the first LRT project in Japan newly constructing railway structures. In this project, the GRS RWs were constructed under difficult construction conditions (i.e., a short given construction period and many divided sections over a long distance in a continuous soft ground area). The end wall face in each preceding section was constructed by placing welded wire mesh boxes filled with gravelly soil at the shoulder of each soil layer and wrapped-around with geogrid reinforcement and left until the start of construction in the next adjacent section. To avoid harmful effects of the ground settlement by the construction of a GRS RW in the next adjacent section on the completed GRS structure in the preceding section, the subsoil was improved by in-place cement-mixing.
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  • Jingwei Wang, Kenichi Sato, Takuro Fujikawa, Chikashi Koga
    Type: Report
    2020 Volume 35 Pages 171-174
    Published: 2020
    Released: December 06, 2020
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    The authors have been studying on the liquefaction suppression associated with the short fiber mixed materials and are confirming its effectiveness. In this research, to examine the effects of short fiber especially the thickness, length and mixing ratio of short fibers on the liquefaction behavior, samples of the short fibers mixed soil produced in different condition were examined by undrained cycling triaxial test. Under these test conditions, there is a tendency that thinner and longer fiber revealed higher liquefaction inhibiting effect in the same mixing ratio.It was also shown that there is an optimum fiber mixing state in liquefaction suppression.
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  • Nahoko Matsumoto, Hiroaki Tanaka, Hayato Yasukouchi, Kenichiro Nakashi ...
    Type: Paper
    2020 Volume 35 Pages 175-178
    Published: 2020
    Released: December 06, 2020
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    Polyethylene pipes for gas have rapidly become widespread due to the establishment of JIS in 1979, the demonstration of earthquake resistance in the 1995 Hyogo-ken Nanbu Earthquake, and the improvement of workability. At the same time, there is an increasing need to take appropriate protective measures to prevent accidents on buried pipes in other works. Protective materials using geosynthetics were developed in 2008 and are becoming widespread nationwide due to their flexibility and impact resistance. And the product was improved for the purpose of further improving the protection performance and workability. In this paper, the effects of differences in geosynthetic materials and configurations on protective performance were confirmed and the results were reported.
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  • Mayu Toda, Noritake Miyazaki, Yutaka Sawada, Toshinori Kawabata
    Type: Paper
    2020 Volume 35 Pages 179-184
    Published: 2020
    Released: December 06, 2020
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    Sheet-piles are used in order to install pipelines. Sheet-pile extraction causes pipe damages such as excessive deformation and cracks. In recent years, it is required that pipelines be buried shallowly because of reduction of construction cost. There are few studies on the influence of construction on the shallowly buried pipe using geogrid. In the present study, model experiments were conducted in order to clarify the influence of sheet-pile extraction on shallowly buried pipe using geogrid. Test results showed that the pipe deformation was small in the case of using geogrid and gravel. However, the reduction of bedding due to the sheet-pile extraction may cause the concentration of earth pressure on the bottom of the pipe.
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  • Takashi Kawamura, Takeo Umezaki, Mikihiro Tanaka
    Type: Paper
    2020 Volume 35 Pages 185-192
    Published: 2020
    Released: December 06, 2020
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    The non-uniformity of the material was evaluated based on the unit area mass, μA*, the initial thickness,h0* and the initial void ratio, e0*, obtained from 400 sheets of non-woven geotextile specimen. Specimens with similar initial conditions were extracted from three different groups. Three kinds of compression test of non-woven geotextile were conducted. The e-logp relationship and coefficients, Cc and Cα, were investigated. In the range of p<100 kN/m2 and t<24 h, these relations and coefficients are influenced by the non-uniformity. On the other hand, in the range of p>100 kN/m2, the effect of non-uniformity becomes small. In addition, it was shown that void ratio keeps decreasing after t=24 h.
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  • Junichi Hironaka, Nahoko Matsumoto, Seiji Kondo, Yoshio Kagei
    Type: Paper
    2020 Volume 35 Pages 193-198
    Published: 2020
    Released: December 06, 2020
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    Large mattress using high strength geogrids for river or marine applications has been used to protect the erosion. The feature of this mattress is to perform lifting construction, underwater construction. The durability of this mattress was evaluated by weather resistance tests and lifting tests. This paper explains a case study and durability evaluation of this mattress. Finally, these results show points to be noted during construction.
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  • Taisuke HIRAI, Takayuki KAWAGUCHI, Dai NAKAMURA, Shunzo KAWAJIRI, Tats ...
    Type: Paper
    2020 Volume 35 Pages 199-206
    Published: 2020
    Released: December 06, 2020
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    A new slope protection work composed of two-layer geocells filled with crushed stone and sandy soil that has the function of suppressing erosion, promoting drainage, seepage control and greening necessary to prevent slope collapse in cold regions were developed. In this study, we carried out this protection work on a full-scale slope with two types of gradient, and examined the influence of the slope gradient on the effect of labor saving and seepage control. As a result, it was found that the developed slope protection work exerts a seepage control function on both slope gradient, and labor can be saved by reducing the number of anchor bars driven into the slope.
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  • Masaharu TATEBAYASHI, Takayuki KAWAGUCHI, Tatsuya WATANABE, Tatsunari ...
    Type: Paper
    2020 Volume 35 Pages 207-214
    Published: 2020
    Released: December 06, 2020
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    In addition to the damage caused by liquefaction phenomenon in Sapporo City, bumps were generated at the boundary with the cut area due to the compression and flow of the embankment area in the eastern part of Hokkaido Eastern Iburi earthquake in September, 2018, and a traffic obstruction occurred. Though the effective restraint method of bumps using geosynthetics has already been proposed, removal and reconstruction must be simple, because construction of buried pipes is sometimes carried out on community roads. In this study, therefore, the authors focused on the geocell which becomes a three-dimensional reinforcement of honeycomb structure, and examined restraint method of bumps in pavement road using geocells by model tests and full-scale experiments.
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