滑坡灾害的机制与力学特性分析

Analysis of mechanism and mechanical characteristics of landslide disaster

滑坡灾害主要是指滑体突然产生较大的土体滑动,巨大的滑动力会摧毁其所遇到的建筑物,造成重大的损失。本文采用数值方法的变模量强度折减法,分析滑坡滑动的位移变化过程,发现牵引式滑坡位移突变性大于推移式滑坡,更容易产生滑坡灾害;相反,推移式滑坡在滑动前会有明显的预警位移,因此提出"塑性"坡的概念,"塑性"坡发生灾害滑动前有显著的变形预警,这样,"塑性"坡可以避免或减少滑坡的灾害。此外,通过计算实例的分析结果,表明牵引式滑坡或当滑面上存在应力水平差异大的情况时,整体极限稳定分析法的安全系数存在偏大的风险。上述结论为避免或减少滑坡灾害开辟新的研究思路。

Landslide disaster mainly means that the sliding body suddenly produces massive soil sliding. Great sliding force could destroy construction,which would cause great losses. The variable-modulus strength reduction method is adopted to analyze displacement process before landslide sliding. It is found that the displacement of retrogressive landslide is more mutational than displacement of thrust load-caused landslide. The retrogressive landslide causes landslide disaster much easier. In contrast,thrust load-caused landslide has obvious warning displacement;therefore,the concept of plastic slope is proposed. Plastic slope can avoid or reduce landslide disaster. In addition,analysis results of calculation examples show that in retrogressive landslide or when the stress level in different part of sliding surface is very different,safety factor by the traditional limit equilibrium method has risk of overestimation. The above conclusions would give new research ideas to avoid or reduce landslide disaster.