膨胀土边坡长期稳定性的一种研究途径

An evaluation approach for long term stability of expansive soil slope

由于降雨等原因,边坡的地下水位往往会在一定范围内反复变化,使得在稳定的地下水位以上的部分岩土体经常处于干湿循环的状态。这对膨胀土边坡的稳定尤其不利。边坡稳定的极限分析方法只适用于比例加载的情况。当其上所受到的全部或部分载荷发生反复变化时,应该采用安定分析来评价边坡的安全性。本文根据率形式的 Koiter 机动安定定理,提出了考虑地下水位往反变化情况下边坡安定的上限分析方法。利用抗剪强度参数折减定义的安全系数,能够定量地计算载荷变化对边坡稳定性的影响。最后,通过一个直立边坡的简单算例证明了本文方法的有效性。

Groundwater level usually changes with the rainfall or some other environmental factors, which may induce alternate wetting and drying to part of a slope. This is especially harmful for the stability of an expansive soil slope. Upper bound limit analysis on slope stability is only applicable for proportional loading. In case of alternate loading and unloading, a shakedown analysis is necessary for its long term safety evaluation. In this paper, an upper bound shakedown analysis based on strong version of Koiter’s theorem is presented to analyze slope stability which subjected to such an alternate load. Safety factor is defined by shear strength reduction of the materials. A simple example is adopted to verify the availability of this method.