厚覆盖层暂态饱和边坡稳定性分析方法

A method for stability analysis of thick overburden slope in transient saturated state

针对暂态水压力影响下的厚覆盖层边坡稳定性分析问题,基于不同暂态饱和区形式,提出了暂态水压力的计算方法,推导了考虑暂态水压力影响的边坡稳定性分析的Bishop方法,并利用VB语言编制了相应分析程序。结合汝郴高速某段覆盖层边坡,对是否考虑暂态水压力影响两种不同计算工况下的边坡稳定性进行了分析。研究结果表明:暂态饱和区厚度越大,边坡安全系数越小;暂态饱和区厚度相同条件下,受暂态水压力影响的边坡安全系数更低;随着暂态饱和区的扩大,边坡安全系数降低率保持扩大趋势,最高达39.79%;边坡潜在滑动面位置在暂态饱和区厚度大于4m后基本与湿润锋位置相切,深度呈增加趋势。

To analyze the stability of a thick overburden slope under the effect of transient pore pressure, a method for calculating transient pore pressure was developed based on the formation and distribution of transient saturated area. A modification on Bishop limited equilibrium method was made with the consideration of the influence of transient pore pressure on stability, and a routine using VB was programmed. The proposed procedure was employed to analyze stability of an overburden slope along Ru-Chen expressway in two calculation conditions whether the transient water pressure was considered or not. The results show that the greater the thickness of transient saturated zone, the smaller the safety factor of slope. The lower safety factor exists in slope affected by transient water pressure under the same thickness of transient saturated zone. With the expansion of transient saturation zone, the decrease rate of slope safety factor keeps increasing, up to 39.79%. The potential sliding surface will be tangent to the wetting front and becomes deeper if the thickness of transient saturated area is over 4 meters.