Among various types of material used for geomembranes, HDPE (High Density Polyethylene) has relatively large thermal expansion rate and elastic modulus. Therefore, stress and strain caused by thermal expansion of HDPE geomembrane is relatively large and it is important to include its thermal dependency in design and installation works.
In the previous paper, the relational formula for the surface temperature of colored HDPE geomembrane was proposed using amount of insolation and air temperature. In this paper, the temperature dependency of white HDPE geomembrane is examined. While relation between amount of insolation and air temperature shows no correlation, relation between air temperature and surface temperature shows good correlation. Further, a comparison with the measured surface temperature and the calculated surface temperature using the formula shows that the measured surface temperature is about 10°C lower than the calculated surface temperature. These results indicate that the temperature dependency of white HDPE geomembrane is mainly affected by air temperature and the effect of insolation is restrained by its color.

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When waste is disposed or some vehicle moves on a liner of landfill, tension stress creates in geomembrane used as a liner. For estimeting the stress, it is important to consider the interface friction characteristic. As seen in the results of direct shear test, frictional resistance depends on the relative displacement of the interface. In this paper, the slip interface model where a relation between frictional resistance and relative displacement is approximated as hyperbolae is introduced to the two dimentional finite element method. Then calculation are conducted to simulate a centrifugal model tests.

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If the settlement of the waste occurs in a landfill, the geomembrane will be pulled down along a side slope. Evaluation of this downdrag force should be very important for the anchorage design. Authors conducted the large scale field test and five types of geotextiles on a geomembrane, and six types of geomembranes were tested. The test results indicat geotextiles have the cooling effect of geomembrane and decreasing thermal stress. The downdrag force depends on a type of geomembrane.

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Large-scale model tests are conducted on geogrid-reinforced soil prepared with dense and loose Toyoura sand. The earth pressures and strains induced along the geogrids are measured during surcharge application and movement of the model retaining wall. One test series are conducted with three geogrid sheets placed horizontally in the model. The other test series are conducted without geogrid reinforcement. The earth pressures are found to become smaller as the model wall moves away from the soil Especially, the earth pressures of the reinforced soil become smaller, compared with those of the non-reinforced soil. The strans along the geogrids also develop as the model wall moves away, and have peaks at the positions within 50cm from the retaining wall.
By comparing the earth pressure changes and the geogrid strains, the discussions are made with respect to the difference in the reinforcement mechanism associated with dense and loose soils.

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Numerical simulation of large plane strain compression tests on a unreinforced specimen and geogrid-reinforced sand specimens was conducted by nonlinear elasto-plastic FEM considering strain localization. The sand specimens were reinforced with 6 and 11 layers of geogrid, respectively. The plane strain FEM analyses, in which the geogrid was modelled as a planar reinforcement, could properly simulate global stress-strain relationships obtained from the experiments either when the equivalent (reduced) tensile stiffness was used together with an interface friction angle similar to the sand, or when the equivalent (reduced) interface friction angle was used together with the measured tensile stiffness. By examining local stress-strain relationships and development of shear band within the specimen obtained from the FEM, the reinforcing mechanism and the effects of vertical spacing of reinforcement layers were clearly understood.

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A nonlinear elasto-plastic FEM analysis considering pressure-dependency and anisotropy in internal friction angle, strain softening, and shear banding was conducted to simulate a series of plane strain laboratory model tests on bearing capacity failure in reinforced sand level ground and slope. The model ground was made of air-dried dense Toyoura sand and reinforced with linear, tensile reinforcing members placed horizontally beneath a strip footing. Model tests on reinforced ground with various reinforcing patterns using different length, number of layers, and vertical spacing of reinforcement as well as the one on unreinforced ground were analyzed. Load-settlement relations obtained by the FEM analyses were similar to those of experimental tests with respect to the effects of reinforcing patterns, although pre-peak stiffness and peak load obtained by the FEM analyses were slightly larger. It was also found that shear banding patterns observed in the tests were well simulated by the FEM analyses.

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A highly complex mechanism of soil reinforcement is not fully explicated so far. A restraint effect which is one of the major functions of reinforcement materials such as geosynthetics is discussed theoretically and experimentally for establishing a rational design in the case of a reinforced embankment construction with walls or panels.
An analytical estimation method using pseudo-confining lateral pressure and pseudo-cohesion is presented in this paper. It was found that the proposed method was able to estimate quantitatively the reduction of earth pressure behind the wall and moreover the decrease in the pressure was concerned in shifting its slip line. The sufficient reliability of the proposed calculation method was also confirmed from several full-scale experimental data.

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Paving Fabrics means Paving Fabrics Interlayer, which is generally called Reflection Crack Deterring Sheet. Paving Fabrics, like most geosynthetics, performs various functions such as reinforcement, elasticity, moisture barrier membrane functions. I will express my Paving Fabrics sales experience of over 20 years, including USA information. When Paving Fabrics is rightly recognized and used correctly, paving cost will be saved and Paving Fabrics will be used widely. Some USA autonomy first examined Paving Fabrics under careful check and its good result has brought about increase of quantity gradually and now 100 million square meters per year seem to be used in USA. Correct use of Paving Fabrics has been gradually recognized in Europe and quantity has increased there. I will also explain the whole of the system, recent activities, some problems and the recycling. Especially, I will stress the advantage of the work of moisture barrier membrane which has been recently been emphasized in USA.

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In practical construction works, installed geotextiles used as filter-sheets are often kept uncovered for several months to a year. Since the friction between geotextiles and rocks due to wave or wind action is severe, the abrasion resistance is an important factor for selecting geotextiles. In this paper, the results of the abrasion resistance test (JIS D 4604) for eight different geotextiles including three non-woven geotextiles, four woven geotextiles, and a multi-layered woven geotextile are presented. The test results are shown in terms of the percent strength retained. Among the test results, 1) the usual woven geotextiles showed a low percent strength retained (about 40%), 2) the coated woven geotextiles with synthetic resin and the multi-layered woven geotextiles showed a good percent strength retained (more than 90%), 3) the non-woven geotextiles showed a moderate percent strength retained (about 65%). Further, weft strands of the usual woven geotextiles shifted laterally and which did not occur with resin coated geotextiles.

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This paper describes that the effect of core shape on the transmissivity of Geo synthetics Horizontal drains (GHDs) based on transmissivity test results. The transmissivity test was carried out to evaluate several stress levels. The single-layered net core (SL), the double-layered net core (DL), the emboss-shaped core (EB) and the non-woven geotextile (NW) were tested.
At lower stress level, DL showed the largest transmissivity. At higher stress level, however, EB showed the largest transmissivity. The reduction of transmissivity of DL and EB were more than 85% and 30% respectively. The largest reduction of transmissivity for DL was considered that the applied higher stress cause a larger flow sectional contraction for DL than EB.

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Roles of sand mat placed on soft ground subjected to embankment loading are horizontal (lateral) drainage during consolidation and improving workability. Recently, it is difficult to obtain sand with high permeability near the site of the construction. On the other hands, non-woven geotextile has very high transmissivity (horizontal permeability) and the thickness of sand mat can be reduced by using geotextile as horizontal drainage. The objective of this paper is to evaluate the transmissivity (horizontal permeability) of non-woven geotextile in soils taking account of compression under load and clogging with soil particles based on results of laboratory tests.

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Reinforcing Technique of embankment with geo-composite which has draining function and reinforcing function is effective for the most of high water content cohesive soils. This paper discusses on the pullout behavior of geo-composite in a volcanic cohesive soil. In a series of laboratory test, it was investigated that the effect of confining pressure or water content of soil specimen. Main conclusions are as follows.
1) Pullout resistant force can be evaluated as the sum of frictional component and cohesive component.
2) Depending on the water content of soil specimen, the cohesive component changes, but the frictional component does not change much.

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The behavior of buried pipeline is influenced by ground water and subjected to uplift force. Therefore, pipeline must be installed to the suitable depth of cover to prevent from floating. Because of this condition, the construction cost of pipeline becomes much expensive. Since large diameter pipeline particularly needs to excavate a deep trench, it is significantly required to bury shallowly due to the declining budget of construction.
This paper discusses the effect of geosynthetics for prevention from shallowly buried pipe floatation based on the results of large-scale pit tests using a FRPM pipe (∅1100). It is found that geosynthetics set on the pipe fixes to the backfill material around the pipe and that total weight of fixed material is effective against pipe floatation.
In addition, a mechanism of prevention from floatation of pipe is estimated about the result that geosynthetics works not with simply pulled out mode but bending mode in the soil.

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A geocell mattress, which takes the interlinked form of three dimensionally build up multiple cells with thin geosynthetics vertical partition walls and the inner parts of which are filled with soils, has wide application such as an improvement of poor bearing power of ground.
A series of two dimensional plate loading laboratory model tests was carried out to investigating major influence factors related to the reinforcement of soft clay ground. It was found from the test results that the lower the bearing capacity of supporting ground was, the higher the reinforcement effects were obtained. Moreover the results indicated that the coefficient of bearing capacity and the bearing power were increased with the width of geocell mattress.

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To evaluate the effect of geosynthetic reinforcement on the embankment, designed by the geosynthetic reinforcing method, the method used as a countermeasure against liquefaction, shaking table tests, slip circular stability analyses and two-dimensional seismic deformation analyses have been carried out. From the results of these tests and analyses, it is clarified that the fatal destruction of embankments could be mitigated to some degree, with the maintenance of the function of embankment. And easy and efficient restoration works can be achieved.
Based on these results, the seismic design procedure for geosynthetic reinforced embankments on a foundation with liquefaction characteristics is proposed using slip circular method. In that it is clarified that the required reinforcement tends to increase in the case of effective stress method and it tends to decrease in the case of total stress method. Finally the deformation mode due to the tensile force distribution at the geosynthetic reinforcement and future problematic issues on the design method in combination with other design methods against liquefaction were described in this report.

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Geonet can cause the bearing capacity to the clay paste ground, and has merits of making artificial island and traffic load on the clay paste ground during very short period and very easy way in comparison with ground improvement.
Therefore, the purpose of this investigation are as follows;
(1) How does the tension distribute on the geonet?
(2) How is the geonet specification when we use on the clay paste ground?
(3) How much is the bearing capacity of clay paste ground with geonet?
This paper shows as follows;
(1) Development of new measuring apparatus which is two dimensional deformation meter (2DDM), consists of a piezometer and a metal detector to understand the geonet shape and strain distribution.
(2) Result of the geonet deformation and strain related with the embankment load.
(3) Theoretical consideration of geonet shape.

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