The Development of Standard Experimental Procedures for Large Scale Model Tests on Geosynthetic-reinforced Soil Retaining Walls with Granular Soil Backfill

• Main Authors: Sang-Che Wu, 吳尚哲
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/33256703863099714224

碩士 === 國立雲林科技大學 === 營建工程系碩士班 === 95 === Most geosynthetics-reinforced soil (GRS) retaining wall have been used as temporary structures in secondary applications. Because of its cost-effective and proven performance, however, the application of the GRS retaining walls to permanent and important structures, such as highway and railway embankments, is rapidly increasing. For permanent and important GRS retaining structures, granular soil is usually adopted as backfill material. In view of the above, this study presents the development of a large plane strain model test apparatus for performing vertical loads on GRS retaining wall and the development of its standard experimental procedures. The preliminary results on the observed failure Zone patterns and the strength and deformation of GRS wall are also reported. The dimensions of the plane strain model wall were 1.2m (height) × 0.8 (depth) × 2 m (width). The deformation pattern of soils could be observed through the front transparent acryl plates attached by latex rubber membranes with marked grid points. In this study, the spacing between the grid points, the siZe of the grid points, and the method for overlapping membranes were respectively estimated and evaluated for having a better observations on the deformation patterns of soils with different particle siZes. Besides, a photogrammetric method and digital image analysis procedures for obverting the deformed grid points and for calculating the associated soil strain distributions were also developed. A series of plane strain model tests on geogrid reinforced soil wall with vertical wrapped-around facing was conducted. Two types of granular sandy gravels with their D50 respectively equal to 10.1 mm and 5.2 mm were used. The adopted reinforcement was polyester geogrid with its strength of 60 kN/m. A monotonic vertical load was applied on a strip footing located on top of the ground.. The results showed that the failure strength and the relevant vertical displacements were increased with an increase in soil particle siZes. The observed deformation patterns indicated that the failure modes were two-wedge failure patterns. The failure plane became distinct after the occurrence of peak strength and the thickness of failure plane and the area of influenced Zone increased with an increase in soil particle siZe. The maximum horiZontal displacement of facing at failure were less than 10 % of the height of wall. Keyword: Reinforced soil retaining wall, plane strain, model test, particle siZe effect, shear Zone, granular soil.