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Y. Miyata, K. Kogure, F. Tanizawa, K. Ogasawara, M. Kameyama, T. Sugim ...
1995 Volume 10 Pages
1-10
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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In constructing embankments with cohesive soil, nonwoven geotextile is frequently used. Authors examined on the applicability of geotextile to horizontal drainage, obtained main conclusions are as follows.
(1) The more dry unit weight is, the higher hydraulic capacity in low confining stress condition is, and the more a decreasing value of transmissivity is.
(2) In evaluating of transmissivity by conducting laboratory test, some decreasing condition should be considered, for example confining stress, clogging and so on.
(3) Nonwoven geotextile has sufficient durability.
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Y. Miyata, K. Kogure, K. Inoue, T. Ishimaru, Y. Hamada
1995 Volume 10 Pages
11-20
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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In the gravel drain method to prevent liquefaction, clogging of drain material is feared. In this study, the property of clogging of drain material and the effect of nonwoven geotextile to prevent clogging are discussed based on the laboratory test results. Additionally, an analysis method to predict pore pressure ratio, which is considerable the effect of clogging of drain material, is suggested.
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Tetsuo Miyake, Michio Tsushihiro, Eiichiro Taki, Kouji Niwano
1995 Volume 10 Pages
21-28
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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Studies are underway for the development of cutoff sheets (CH-200) for use at final disposal yards, which are capable of preventing the expansion of perforations and of self-repair. The study reported here was concerned with the basic properties of these cutoff sheets, in terms of the effects of water pressure, temperature and quality, as well as the structure of the sheets themselves, on their capacity for self-repair. It was found that the capacity for self-repair could be maintained under water pressure of up to 3kgf/cm
2, and at the temperatures normally encountered in groundwater and waste.
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Michio Tsuchihiro, Shoji Seno, Mitsutoshi Nakamura, Tetsuo Miyake, Eii ...
1995 Volume 10 Pages
29-36
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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The installation of seepage control systems using liners made of impermeable materials has been made obligatory at final disposal yards for waste. Sheets made of synthetic rubber and similar materials have conventionally been used for this purpose, but a problem has been presented in recent years by the leakage of contaminated water through perforations and defective joints in the sheets. In this study, a large permeability test device were used to examine the cutoff performance of self-repairing geomembrane which is newly developed as a cutoff material for waste disposal yards, we report on character of the self-repair performance of this geomembrane.
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Nobuo TAJIRI, Yoshiaki TSUKADA, Makoto YAMAMOTO, Yoshitaka OCHIAI, Kiy ...
1995 Volume 10 Pages
37-46
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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To examine the effects of facing types upon stability and deformation of geotextile reinforced soil walls, failure experiments of full-scale models with different facings of 6m high were conducted. Findings from the experiments are as follows.
(1) The horizontal displacement of EPS blocks was larger than that of concrete blocks during construction, showing that deformation during construction could be reduced by the weight effect of facing materials. For divided type concrete-panel wall, the horizontal displacement was larger than that of other type of panel wall.
(2) In every case, the vertical pressure at the bottom of the facing was larger than the self dead weight.
(3) Maximum tensile forces distributed on the reinforcements after the construction were nearly equal at upper 3m part of facing and were smaller at lower 3m part compared with the required tensile forces which the effects of facing was not taken into account. The greater the longitudinal rigidity of facing material became, the more salient this tendency was.
(4) Tensile-force distribution similar to that on the main reinforcements was observed on sub-reinforcements suggesting that the sub-reinforcements were contributing to the stability.
(5) The shape of the slipping surface of the EPS-block wall after the failure was most similar to that of slip circle by the current design method. The failure surface of slipping of the concrete-block wall was similar to that of slip circle analogous to Coulomb's active failure surface, and the slipping shape of the concrete-panel wall to that of two-part wedge type. In case of the facing material of low rigidity, the failure was progressed as the creep phenomenon
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Tomoki Nakajima, Yuji Ohki, Kenji Oda, Hiroaki Miyatake, Kiyomasa Doba ...
1995 Volume 10 Pages
47-56
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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It is known that high stability and deformation control can be assured in geotextile reinforced soil wall. if facingrigidity is improve. To verify this, a field performance test was conducted on a 8-meter high soil wall, with a face of large concrete blocks 50cm high, 100cm wide and 35cm thick. Information obtained through measurement during construction of the reinforcement materials, horizontal displacement of wall surface, settlement of wall foundation and earth fill, subgrade reaction, and lateral earth pressure is as follows.
•Approximately 1% of maximum reinforcement strain, measured at the completion of construction, is acceptable for the stability of the reinforced soil wall.
•Concrete block walls are easy to construct because of their self-supporting characteristics.
•Sub-reinforcements contribute greatly to the stability of the reinforcement soil wall.
•A 65-mm horizontal displacement in the forward direction is observed at the middle of the wall upon completion
•The foundation subgrade reaction measured at the rear of the wall is equivalent to the dead weight of the concrete blocks.
•The horizontal displacement of the wall is related to foundation settlement, it can be concluded that taking appropriate design measures is essential for soil wall foundation of this type.
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You KAWAGUCHI, Katsuhiko MAKIUCHI, Kunio MINEGISHI
1995 Volume 10 Pages
57-62
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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Geocapsule which envelops cohesionless granular materials by geosynthetics may develop an apparent cohesion component as well as its frictional resistance. In this study, the strength and deformational properties of geocapsule-reinforced dry fine sands were invesitigated in an uniaxial compression test.
The experimental results showed that the increase in the uniaxial compressive strength and by decreases in the failure strain. The apparent cohesion of geocapsule-reinforced sand can be estimated using the shear box test data of the sand.It was found that stress-strain relationships of geocapsulated soil sample were affected by the volume of the specimen.
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Jiro KUWANO, Yosinori IMAMURA, Tatsuo IMANARI, Yoji KIKUCHI, Naoki HOR ...
1995 Volume 10 Pages
63-72
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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Reinforcement effects were recognized by study until now on continuous fiber reinforcement method with pit sand. For extensive utilization of the method, effects of cementcontent on the reinforced sand, application of the reinforcement method to Shirasu and effects of fiber on the reinforced sand were studied through box shear tests and erosion tests.
Cement content is very effective to the reinforced sand.
The reinforcement method is applicable to Shirasu.
The reinforced sand is improved by selecting the appropriate fiber.
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A. Nakane, M. Taki, H. Miyatake, K. Dobashi
1995 Volume 10 Pages
73-82
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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It has already been shown that the stability of the geotextile reiforced earth walls was improved with the use of rigid facings that brought about the reduction of overall deformation and the amount of tensile force generated in geotextile. To evaluate the effects of facing rigidity, stress-deformation behavior must be analyzed based on the interaction of facings, geotextiles, and soils.
A numerical analysis using a two-dimensional elasto-plastic FEM taken account of the construction process was conducted to clarify various aspects of the behavior of a reinforced earth walls measuring 10.0m high. Three types of facings were analyzed: the wrapped-around wall face method, the concrete panel face method, the concrete block face method. In addition, the slope of wall was varied from 1:0.0 to 1:0.8 (pitch of 0.2). The results showed that facings performed using the block and panel face method, which provided higher rigidity than the wrapped-around wall face method, could be increased the stability of the reinforced earth walls under the characteristic bound coditions be satisfied:
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Osamu MATSUO, Teruhisa FUJII, Naozo FUKUDA, Nobuo TAJIRI, Ryosuke UZUO ...
1995 Volume 10 Pages
83-92
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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This paper describes the results about two-dimensional seismic deformation analyses on geosynthetics reinforced embankment model. This model was supposed to be filled on liquefactive foundation that improved by compaction method. Findings from the analyses about reinforcing effect of geosynthetics reinforced embankment are as follows.
(1) It would not be expected about additional settlement reducing effect for geosynthetics reinforced embankment filled on foundation improved by compaction method.
(2) The embankment could be maintained their function by application of laying geosynthetics. For the range of deformation especially lateral component of embankment is constrained.
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Kunio MINEGISHI, Katsuhiko MAKIUCHI
1995 Volume 10 Pages
93-101
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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In this study, a series of laboratory two-dimensional model tests were carried out using geosynthetics and cohesive soils. Several geowovens of different tensile strength were laid on the surface of and at the given depth of soft clay ground. The deformation of the ground under strip loadings were observed and the interface friction between geosynthetics and cohesive soil was determined. A mechanism of geosynthetic-reinforcement on the bearing capacity of clay ground was considered and the evaluation method was proposed based on the modified Terzaghi's bearing capacity theory.
As the experimental results, a ground surface deformation can be expressed in the from of a quadratic equation and the radius and the tangent of surface deflection can be taken more accurately than the conventional methods. It was found that the role of hammock's effect is significant. Moreover, it was observed that the reinforcement of geosynthetics did not displayed at the deeper place than a certain laying limit.
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Masami FUKUOKA, Kiyoshi MISAWA
1995 Volume 10 Pages
102-111
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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Reinforced soil embankments deform by percolation of rain water after end of construction. There are cases which can be allowable and not. Why such deformation occur should be investigated. Noticing that those deformation are due to physical properties of soil, relationship between stress-strain relationship was studied by the laboratory rest. The deformation property is expressed by coefficient of linear deformation and Poisson's ratio or Poisson's number. Usually fill materials contain large gravels. As fills are relatively low, stresses in the fills are low. These conditions should be taken into account when the testing apparatus is designed. A large steel sylinder attached by wire strain gages filled with soil sample was subjected to vertical load by a jack. Coefficient of linear deformation and Poisson's number were obtained by computation. A kind of simple shear apparatus was used to obtain shear modulus. soil sample
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Satoru TAKAHASHI, Shigeyoshi IMAIZUMI, Yukimitsu YOKOYAMA, Masayuki TS ...
1995 Volume 10 Pages
112-122
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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Multi-layered geosynthetic liner is often used in landfill. In a design practice, it is very important to know shearing behavior of each geosynthetics on side slope of the landfill. In this paper, new shearing test device which has two shearing interfaces was developed, where shearing force was applied to the upper-layer and tensile forces induced in middle and lower-layer were measured respectively through load-cell. 10 cases of test were performed varying two interfaces friction, normal force and rigidity of second layer.
Consequently, it was founded that
(1) Tensile force induced in the middle-layer increase with increasing of rigidity of the middle-layer and with decreasing of normal stress given on the interface.
(2) Tensile force can mobilize even when the interface friction between upper and middle-layer is smaller than the one between middle and lower-layer. This demands a revision of Koerner's method relating to stress transmission among geosynthetics.
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Masayuki Tsuboi, Yoshitaka Tadama, Hideki Miyaji, Tomohide Tsuda, Shig ...
1995 Volume 10 Pages
123-133
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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This paper presents the behavior of strength at yield and secant modulus of HDPE Geomembrane, which is recently well known for landfill, at different temperature conditions. The equations belows are obtained from the test results.
qy=240-2.79t qy: strength at yield, t: temperature
E=8180·10-0.0125t E: secant modulus at 1%
These mean that the relation between strength and temperature is linear, but the relation between secant modulus and temperature is exponent. The most important point for designing or application is that HDPE geomembrane has extremly high modulus at low temperature. And the induced load of HDPE geomembrane at cooling condition is measured and compared with the value obtained from coefficient of expansion and secant modulus at different temperature.
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Jun Otani, Kentaro Yamamoto
1995 Volume 10 Pages
134-141
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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The earth reinforcement practice using several types of reinforcing materials has been widely used around the world in this three decades, and the design methods for these structures are mainly based on limit equilibrium method. Although in the current design method it is assumed that the failure mechanism of the reinforced ground is same as that of non-reinforced ground such as the mechanism proposed by Terzaghi, the real failure mechanism of the reinforced foundation ground has not been investigated. In fact, this is more progressive type of failure than that of the non-reinforced ground because of the tensile property of the reinforcing materials.
In this paper, the behavior of real localized deformation of reinforced foundation ground is investigated based on the model loading test using the simulation of the ground by aluminum rods. A series of the model loading test with and without reinforcing materials are conducted. And not only the improved bearing capacities but also the localized deformation property of the reinforced foundation ground is investigated by taking the photograph. After translating this photograph to the photo CD, the rigid motion is analyzed using computer software. The relation between the bearing capacity property and the progressive localized deformation property is also investigated.
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Yoshiharu WATARI, Takayuki KISHIMOTO, Hiroshi HIRANO
1995 Volume 10 Pages
142-148
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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The plastic drain method is often used at the very soft ground improvement construction field for consolidation time saving and increase of soil strength by shortening of consolidation drainage distance.
As this drain material has no comprssibility, material is corresponded by the bending at the ground settlement. Now, traditional drain materials are bended freely at the any parts of drain by the homogeneous rigidity of longitudinal direction. There is some possibility of problem between design assumption and field by the large partial bending of drain material. The influence of this phenomenon at the ground improvement result is considered, model tests of bending of drain materials in the soils were performed.
This paper described the results of the above tests and the plastic drain material that has regularity of bending property by the regular reduction parts of drain material rigidity.
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PUNCTURE RESISTANCE AND IMPACT RESISTANCE
T. SHIMAOKA, M. HANASHIMA, K. MIZUTA, S. KUWATSUKA, T. HIRAI
1995 Volume 10 Pages
149-157
Published: November 30, 1995
Released on J-STAGE: December 17, 2009
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The use of a geomembrane liner in the landfill application is rapidly increasing lately for the purpose of preventing an environmental pollution problem by leachate. However, neither a testing method nor a quality standard for geomembranes has been established in Japan. Thus, it is our urgent task to establish related testing and evaluation methods for various properties of geomembranes such as general mechanical characteristics, endurance (thermal degradation, chemical degradation, biological degradation, etc.), durability and puncture resistance in the soil and under natural environments. Also, the cause of damage and the effect of load to geomembrances when used as a water-shielding layer have not fully been clarified by field tests yet. In our study, the basic twelve (12) mechanical property tests have been conducted aimed at finding out the main cause of damage ti geomenbranes, as well as to evaluating the subject testing methods and their applicabilities.
In this report, the test results of puncture resistance and impact resistance of geomembranes are reported.
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