在边坡局部失稳中传递系数法与强度折减法的计算比较

The Calculation Comparison of Transfer Coefficient Method with Strength Reduction Finite Element Method in Slope Local Instability

在考虑非饱和基质吸力条件下,基于传递系数法的计算原理,开发了可考虑基质吸力的传递系数法相关计算程序,并且针对下土地岭边坡进行了稳定性分析,同时与强度折减有限元计算结果进行了比较研究。对于具有滑带、坡体狭长不规则等特点的下土地岭边坡,可能存在局部滑动先于沿整体滑带滑动的失稳情况。研究结果表明,考虑基质吸力逐步减弱直至丧失的过程中,传递系数法与强度折减有限元法均可在一定程度上反映非饱和土边坡的安全系数降低的现象,但传递系数法在分析边坡的局部滑动问题中具有明显的局限性,而强度折减有限元法则可以通过计算的位移增量云图和等值线确定潜在的局部滑动面。

In the condition of taking the unsaturated matric suction into consideration, based on the prin- ciple of the traditional transfer coefficient method, this paper develops a corresponding program on trans- fer coefficient method with considering matric suction, and analyzes the stability of Tudiling slope. At the same time, comparison of the results of the transfer coefficient method is made with that of the strength re- duction finite element method. For the Tudiling slope being narrow in thickness and irregular in shape, there may exist a kind of instability that the sliding of local surface is earlier than that of whole slide belt. The results show that, with matric suction gradually decreasing, the transfer coefficient method and the strength reduction finite element method both can reflect the decrease of safety factor in the unsaturated soil slope, but the transfer coefficient method has obvious difficulty in analyzing the local sliding, while the strength reduction finite element method is advantageous to determine the potential local sliding sur- face through the isoclines of incremental displacement.