The laboratory pull-out test of the nonwoven fabric confined in sand was performed to examine the deformation of the geotextile confined in soil. As a result, because the lateral contraction of the nonwoven fabric decreases as normal stress increases, it was able to estimate that the lateral contraction will not develop as the lateral contractible force of the nonwoven fabric is equal to the friction between soil and nonwoven fabric. In additions the distribution of shear stress occurred between the geotextile and the soil was examined by the mechanical model. As the result of analysis, it is examined that the distribute condition of shear stress will be controlled strongly by the modulus of rigidity of the geotextile.

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In this paper, we discuss some factors affecting the strength of in-situ Geotextile joints. Some results of the tensile tests show that the tensile strength of Geotextile itself, the number of stitch lines, the type of seam and the number of tieing are the principal properties of the tensile strength of in-situ jointing systems on Geotextiles.

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Large scale experiment on the behavior of test embankments reinforced with spun-bonded non-woven fabrics were carried out under artificial condition in order to investigate the erosion protection function of the fabrics. Test embankments were constructed using silty sand and have a height of 2.75m and solope ratio of 1:1.0. One of them was non-reinforced and the others were reinforced with fabrics, having a spacing of 60cm and 30cm respectively. Total cumulative rain fall was 453mm.
Acording to the test results, spun-bonded non-woven fabrics have an remarcable function of restraining erosion which proceed from the toe of the embankments and have another dintinguished function of draining seepage water through them and delaying the speed of strength reduction of the fill materials due to the increase of water content of them. And the denser the spacing of the fabrics, the more effective they are.

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The purpose of this test construction of retaining wall reinforced with geotextiles was to ensure the application and to extract issues for design method under examination. The constructed retaining wall was based on this design method and was mesured the behavior for a long term.
As the result, it was found that this design method was available for the retaining wall. But, it was necessary to examine in detail about the spacing of reinforcement and the facing.

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We proposed a new economical reinforced embnkment method.
In this method, relatively short planar geotextile are used together with a continuous rigid facing structure placed after the filling of backfill is completed.
For develop this method, two full-scale test embankments having near-vertical slopes were constructed in 1988, one using clay and one using sand.
Three sections of sandy embankment performed static and dynamic loading tests. This paper describes referring to the results of those loading tests.

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This paper discusses about the effects of the tensile stiffness of the reinforcing materical upon the deformation and tensile stress in the reinforced embankment. First, it is demonstrated that the finite element method could accurately predict the actual deforming patterns of the embankment through comparing the observed data at the full-sized reinforced embankment model by the FRP geotextile (height: 5m, slope: 1:0.3) with the analytical results. The validity of the finite element method has been also confirmed by comparing the theoretical results by the slope stability analysis for the non-reinforced embankment with the corresponding results by the finite element method. Next, the stability of the geotextile as the reinforcing material has been examined by the finite elememt analysis in the five embankment models reinforced with the various tensile stiffness.
Through the analyses proposed in this paper, following results are obtained:
1. The deformation of the embankment could be controlled to some extent due to the use of the reinforcing materical whose tensile stiffness may be higher than the modulus of elasticity of the ground.
2. The tensile strenght of the reinforcing materical could increase with its tensile stiffness while the rate of the increase could not be large.

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This paper descrives some results of analysing the report by Professor L. R. Anderson, which measured forces acting on the steel mats used for strengthening a high retaining wall, in order to investigate mechanism of reinforcing retaining walls by extensible geogrids. As the results of analysis, friction between the mat and the soil was obtained. There is a point which gives zero friction about 2m from the front wall. The part of the mat between the front wall and the above point retains the forward movement of the soil. On the other hand, the part behind the point acts as an anchor. The elongation of the mat is negligible small compared with the horizontal movement of the soil. Further study is needed to deal with the interaction between soil and more extensible geogrids.

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During excuting a natural steep slope Stabilizing work, collapse occured in the slope. That reason was that air raid shelter excavation made the slope weakend.
Since a limitation of land space and machinery work condition, geogrid reinforced embankment method had chosen for the slope repair work. In this report design and performance of this work is presented as a case history.

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In order to construct a geogrid reinforced embankment on soft ground, it is significant to forecast its deformation in terms of the function as well as to evaluate safety factor.
In this paper, a stability analysis for geogrid reinforced embankments with various properties was carried out using the circular are method which can evaluate two aspects of reinforcement force and embankment deformation, As a result, it is concluded that the reinforcement effect by geogrids can be widely different even if they have the same tensile strength.

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This report presents the spring value's improvement of embankment which are reinforced which geotextites the basement of embankment are soft-ground improved by stakes, the insitu test consists of static and dynamic roading.
As a result, it showes more efficient strength and more stress concentration to the top of stakes than no reinforced one. But the relation between ground and top of stakes is impossible to realize the dependence of stess strength and the assigneed stress effect is smaller than it by design.

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As a countermeasure against land sliding through a cut-slope in a complicated terrain, a soil reinforcement method and re-vegetation method, both using continuous fibers, were applied, and a monitoring was conducted to clarify their applicability. Afterwards, a follow-up survey was carried out to grasp the effectiveness of artificial soil with woody plants seeds for the vegetation growth. This is an interim report on this project.

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Seismic stability of reinforced earth retaining walls with geotextiles has been demonstrated through laboratory model tests by authors.
Additionary, the laboratory model tests for reinforced earthretaining walls having several types of facings carried out.
The results showed that light facing increases the seismic stability of the earth walls.

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