强度折减法在高含水滑坡稳定性分析中的应用

Application of Strength Reduction Method in Stability Analysis of A Landslide with High Water Content

文章依据滑坡体岩体破碎、地下水丰富、坡体含水量高、滑坡面积大、厚度小、稳定性差等特点,选取青海省麦秀山1#滑坡为例。结合麦秀山地区的工程地质特点,利用FLAC-3D有限差分程序,基于强度折减法对该滑坡进行了稳定性分析。通过对滑体岩土体强度指标的折减,模拟地下水对岩土体的影响,当边坡的塑性区由坡脚贯通至坡顶、坡体上特征点的位移值产生突变,且无限制的增长时,认为边坡达到临界破坏状态,此时的强度折减系数即为滑坡的稳定系数,同时可得到滑坡失稳破坏的潜在滑动带,以揭示滑坡的失稳破坏机理。分析计算表明:强度折减法不仅能够模拟出滑坡渐进破坏的过程,而且所求得的稳定系数更符合滑坡的实际状态,在滑坡稳定性分析中具有明显的优势。

According to the features of landslide -rock breaking, abundant groundwater, high water content, small thickness and large area, and poor stability as well as combined with the engineering geological characteristics of Maixiushan area, the paper selected Maixiushan 1^# landslide to analyze the stability of landslide with the Strength Reduction Method through FLAC-3D Finite Difference Program. With the reduction of the strength index of the rock mass of slide, a state was defined as the critical failure while the plastic zone appeared successionally from the toe to the head of the slope, and the displacement value of the characteristic points on the slide mass changed in a sudden and increased unlimitedly. The reduction factor of the strength at the critical failure was regarded as the stability factor of the slope, meanwhile the potential slide zone could be discovered, for revealing the failure mechanism of High-Water-Content landslide. The results showed that the strength reduction method was not only able to simulate the actual process of the slope failure, but also the safety factor obtained from this method was more confirmable to the real slope stability state. In a word, this method was fairly advantageous in stability analysis of landslide.