地基对加筋土挡墙影响的对比分析

为了分析地基对加筋土挡墙的影响，开展了两组离心模型试验. 首先根据相似理论确定试验相似比尺，其次根据相似比尺选取试验材料并制作模型进而开展砂土与黏土地基工况时的模型试验，最后采集并分析了填筑期与施工期的墙体位移、水平土压力、基底竖向应力与筋材应变. 结果表明:砂土地基时墙体的位移最大值位于结构的上部；黏土地基填筑阶段时墙体的位移约为砂土地基时的3倍并且加载阶段时墙底的位移可达30 cm；水平土压力系数沿着高度方向非线性分布，同时加载期的数值小于填筑期时的值；黏土地基时的墙背水平土压力系数小于砂土地基时的数值；与砂土地基时相比，黏土地基的变形可以减小面板底部竖向应力集中的趋势，使其竖向应力与自重应力比值接近1.0；与砂土地基时筋材拉力相比，由于黏土地基时墙体位移较大，因此此时底部筋材应力可增大3倍，同时筋材应变最大值出现的位置相对更远离墙面. 

Comparative Analysis of Influence of Foundation on Reinforced Soil Retaining Walls

Two centrifuge model tests were carried out to study the influence of foundation on reinforced soil retaining wall. Firstly, the similarity scale was obtained using the similarity theory. Then, materials used in model tests were determined according to the scaling law and models with sand and clay foundations were designed. Finally, values of displacement, horizontal earth pressure on the wall, vertical earth pressure, and reinforcement strain during the construction stage and the loading stage were collected and analyzed. Results show that the maximum horizontal displacement was located at the top of the structure for the wall constructed on compacted sand foundation; the horizontal displacement of the model wall constructed on clay foundation at the end of the construction was about 3 times that constructed on sand foundation and its bottom displacement could increase to 30 cm in the loading stage; the horizontal earth pressure coefficient was nonlinear along the wall height and was smaller in the clay foundation case. Besides, the value in the loading stage was smaller than that in the construction stage in both cases. Compared with the wall constructed on sand soil foundation, the deformation of the clay could reduce the concentration of the vertical stress at the bottom of the wall facing, resulting in the ratio of the vertical stress to the self-weight stress being close to 1.0. As the displacement of the wall constructed on clay foundation increased, the strain was about 3 times that with compacted sand foundation, and the position of the maximum reinforcement strain was far away from the wall facing.