天然滑坡的位移反分析

Back Analyses of the Displacements of Landslide

本文提出了天然滑坡应用决定论模型的思想和有限单元法进行位移反分析的新方法。考虑的环境量主要为地下水位和江水位,效应量为钻孔倾斜仪测得的位移。为了使利用线弹性理论成为可能,从位移中挑选出以弹性为主要部分的卸荷回弹位移作为我们研究的对象。在采用直接法求出了滑坡体的等效弹性模量以后,用该弹性模量和有限元法进行了稳定性计算。等效弹性模量与试验值较一致;有限元法计算的稳定性安全系数与用沙尔玛法计算的接近。

In this paper the idea of establishing deterministic model for safty evaluation of natural landslide is described and a new method for back analysis of the displacements with finite element method is suggested. The environment quantities considered here are mainly underground water level and the river level,while the effect quantities are the displacements measured by borehole inclinometer. A stretch of time was choosen, during which the slide mass was unloaded and, mainly,elastic deformation (displacement) of the slide mass occurred, so that the assumption that the rock mass is isotropic and elastic could be used and the analyses could be conducted using the fundamental epuations of elasticity theory. An equivalent elastic modulus of the slide body of about 1450MPa was obtained using direct method of back analysis. This value is very close to that obtained from laboratory test on rockfill samples. With this equivalent elastic modulus stability analysis of the slide mass was conducted by finite element method and the safety factor obtained is approximately the same as those obtained from the analysis by Sarma's method.