裂隙膨胀土边坡稳定性分析方法研究

Study of Stability Analysis Method for Expansive Soil with Fissures

基于反映裂隙影响的膨胀土边坡稳定性的极限平衡法,提出了通过将边坡划分为裂隙充分发展区A、坡顶张拉裂隙区A′、裂隙发育不充分区B、坡顶张拉裂隙区B′、坡脚雨水积聚影响区C以及无裂隙区D,近似反映坡顶张拉裂隙以及坡脚渗流积聚对边坡稳定性的影响.研究确定了C、B′区域的强度指标取值,尝试对该极限平衡方法进行完善补充.利用毕肖普法进行实例计算,结果表明:单独考虑坡脚雨水积聚和坡顶张拉裂隙影响时边坡安全系数分别下降0.271和0.082,同时考虑两者影响时降幅达9%.提出的方法能够反映膨胀土滑坡的特点,同时可以计算裂缝发展极限状态时边坡的稳定状态.

A new method was proposed based on the slope stability analysis of expansive soil under fissure influence,by dividing the slope into fully fissures area A,top slope tension crack influence area A′,the partially developed fissures area B,top slope tension crack influence area B′,toe of slope rainwater accumulation influence area C,and no fissures area D,to reflect the influences of tension fissures and rainwater accumulation on slope stability approximately.And the strength indexes were determined for areas Cand B′from this research,trying to improve the limit equilibrium method and make it for perfect complement.The computed results using bishop method of an example showed that when the influence of rainwater accumulation and tension crack considered separately the safety coefficient of slope dropped respectively 0.271 and 0.082,and the amplitude reduction was 9% when consider them together.The proposed method can not only reflect the characteristics of expansive soil landslide but also calculate the slope stability for fissures at ultimate state.