加筋土挡墙静载模型试验及其力学性能研究

为研究加筋土挡墙在墙顶荷载作用下土体受力和变形形态，通过改变筋材层数、筋材长度和替换加筋材料等方式对加筋土挡墙进行了4种工况的模型试验。对4种工况下的加筋土墙体内竖向土压力、墙面水平位移、墙顶竖向位移和筋材应变等进行对比研究。研究表明，挡墙上部竖向土压力增长较快且各层竖向土压力最大值由加载点下部向墙面处移动；墙顶荷载超过130 kPa时，由于不均匀沉降，第5层筋材对应墙面处有向内收缩趋势，墙面水平位移最大值大约在上三分点位置；整个加载阶段，筋材总体应变值增幅不大且远小于筋材设计应变峰值；增加挡墙内筋材层数和增加筋材长度均可提升挡墙各方面性能，但增加筋材层数提高效果要优于增加筋材长度；使用废旧轮胎代替单向格栅进行加筋可有效提高挡墙整体性能，分散超载引起的附加应力，有效减小墙面水平位移和墙顶竖向位移。

Model test and mechanical properties study of reinforced earth retaining wall

Model tests in laboratory were conducted to investigate the behaviors of reinforced earth retaining wall of block face under the loading on the top of the retaining wall. In the model test, four conditions were simulated. The results show that, the vertical earth pressure on the upper part of retaining wall increases rapidly and the maximum vertical earth pressure of each layer moves from the lower part of the loading point to the face of wall. When the load at the top of wall exceeds 130 kPa, due to uneven settlement, the wall surface corresponding to fifth layer of reinforcement tends to shrink inward, the maximum horizontal displacement of wall surface is located in 7/10 of the wall height. In the whole loading stage, the overall strain value of the reinforcement does not increase significantly and the actual strain value of the reinforcement is much smaller than the maximum design strain of the reinforcement. Both increasing the number of the reinforced layers in the retaining wall and increasing the length of reinforcement can improve the performance of the retaining walls. However, the effect of increasing the number of the reinforced layers is better than that of increasing the length of reinforcement. The use of waste tire instead of unidirectional geogrid can effectively improve the overall performance of retaining walls, disperse additional stress caused by overloading, reduce the horizontal displacement of the face of wall and the vertical displacement at the top of the wall.