刚性挡土墙后三维被动滑裂面的模型试验

针对无黏性土体，采用模型试验的方法，研究平移模式下刚性挡土墙后被动破坏滑裂面的空间形态。自主设计一种模型试验装置，重复开展6次试验，通过记录挡土墙后土体中预埋脆性玻璃条断裂的空间坐标，复原土体发生滑动的位置，绘制出挡土墙后滑裂面的三维形态图。试验结果表明：挡土墙后滑裂面具有明显的三维效应；挡土墙宽度内滑裂面纵向高度呈先缓慢增高后近似直线增高的曲面，初始破裂角度为9°，平均破裂角为26°，朗肯土压力理论的破裂角为28°；最大纵向破裂面长度为1.8倍挡土墙高度，与经典土压力理论的平面假定基本一致；滑裂面均有一定的横向扩展，主平面投影以初始扩散角约45°的斜线往外扩展，距离挡土墙最远处是宽度为0.7倍挡土墙宽度的水平线，斜线与水平线之间以半径为挡土墙宽度的圆弧过渡连接。研究结果为分析土体被动破坏的滑裂面空间形态提供了试验依据。

Model tests on 3D slip surface of passive failure behind a rigid retaining wall

The research about spatial form of non-cohesive soil slip surface in passive failure behind the retaining wall in translation was done by the method of model tests. A model test device was designed to carry out 6 passive failure tests for soil behind the retaining wall. The spatial coordinates of the points where the fragile glass strips embedded before break were recorded, in order to determine the location where the soil slide occurred and plot the spatial form of slip surface behind the retaining wall. The test results show that: the 3D effect of the slip surface behind the retaining wall is obvious; in the width of the retaining wall, the slip surface height in longitudinal direction slowly increases in the beginning and then increases in an approximately linear pattern. The initial fracture angle is 9° and the average fracture angle is 26° while the Rankine theory fracture angle is 28°. The maximum length of longitudinal fracture surface was 1.8 times the height of the retaining wall which is generally consistent with the plane assumption of the classical soil pressure theory. The slip surface has a certain horizontal extension, and the principal plane projection extends with initial diffusion angle of about 45°. The form which is the most distant from the retaining wall is a horizontal line with 0.7 time the width of the retaining wall, and the diagonal and horizontal lines are connected with an arc with a radius equal to retaining wall width. The results provide experimental reference for analyzing the spatial form of slip surface in passive failure.