天水市某典型黄土边坡块石支护稳定性效果分析

Stability Analysis of a Typical Loess Slope Supported by Block Stone Retaining Wall in Tianshui

摘要:

以天水地磁013台黄土边坡为研究对象，通过现场勘测、室内强度试验确定了该边坡的土质条件及其相应的土层力学性质，根据相应规范的要求提出运用块石挡土墙对此边坡进行上下分层支护。采用强度折减理论验证了边坡施加支护后的稳定性评价。结果表明，相比未加块石支护的边坡模型，采用块石支护的边坡的安全系数达到1.41，属稳定状态；同时块石支护可以有效地减小土体的水平方向位移，并约束土体总位移向临空面滑动。

Abstract:

In this study，field and laboratory tests are used to obtain the soil conditions and mechanical properties of a 013 loess slope in Tianshui.This study introduces a hierarchical support scheme using a block stone retaining wall，and the stability of the slope is verified on the basis of the strength reduction method.Moreover，the safety factor and the equivalent plastic strain law of this slope is determined before and after application of the support using ABAQUS software in which the yield criteria of the corner point circumcircle of the Drucker-Prager （D-P） criterion is adopted.The horizontal displacement law of the slope before and after the support is also obtained using ABAQUS.The results show that using the finite element strength reduction method, the safety factor of the slope without support is 0.59；in ciontrast，the safety factor of the slope in block stone retaining wall is 1.41.Therefore，the stability state of the slope is reached. Moreover，on the basis of the finite element strength reduction method，the equivalent plastic strain zone of the slope without the stone retaining wall is located at the foot of the slope，and the failure form of the slope is local soil failure with a maximum plastic strain of 0.023.Therefore，no sliding surface is present in the slope.By comparison, an equivalent plastic strain zone occurred under the slope supported by the rock block，and the failure form of the slope is also local soil failure. In addition，the maximum plastic strain is 0.02.With further reduction of the soil strength，the upper soft soil will develop a sliding surface through the slope in the stone retaining wall.At the same time，the stone retaining wall will decrease the horizontal displacement of the soil，which can prevent the total displacement from sliding to a free surface.