基于强度折减法的土石坝边坡稳定分析与探讨

Slope Stability Analysis of the Earth Rockfill Dam Based on the Strength Reduction Method

在传统的土石坝边坡稳定分析中,通常采用简化毕肖普法或瑞典圆弧法,分别计算上、下游边坡的滑动安全系数,然后根据规范评判边坡的稳定性。本文应用有效应力原理,以初始应力方式将渗流场导入到位移应力分析中,基于强度折减法对坝体整体进行弹塑性分析;分别采用塑性区贯通和位移突变失稳判据,得到坝坡的最小安全系数,并将其与简化毕肖普法计算结果相比较。研究表明:采用强度折减法进行土石坝边坡稳定分析虽然是可行的,但仍存在一些问题。最后,对强度折减法在土石坝边坡稳定分析中存在的两个问题进行了初步的探讨。

In the traditional slope stability analysis of the earth rockfill dam, simplified Bishop method or Swedenarc method is usually used to calculate separately the slide safety coefficient of the upper and downstream slope, then the slope stability is evaluated according to code. The effective stress principle is applied and seepage field considered as the initial stress is imported into analysis of displacement and stress, then based on finite element strength reduction method, the whole dam body is conducted using elastic--plastic analysis, criterions of plastic zone transfixion and displacement saltation is used to get the minimum safety factor of the slope compared with the results by simplified Bishop method. The results shown that finite element strength reduction method was feasible to analyze slope stability of earth rockfill dam, but some questions still exists. Finally, two questions of the applications of finite element strength reduction method in slope stability analysis of embankment dam are preliminary studied.