强降雨作用下的浅层滑坡稳定性分析

根据实测和室内物理力学试验结果以及工程实践，研究强降雨作用下浅层滑坡稳定性系数与滑面带抗剪强度指标及滑体饱水面积比三者的关系，建立其数理统计相关式。依据建立的数理统计相关式，对采用不分离接触弹塑性有限元强度折减算法分析强降雨作用下浅层滑坡稳定性的难处进行初步探讨。结果表明：首先，可以利用建立的数理统计相关式，选择不同滑体饱水面积比求出强降雨时滑面带的等效抗剪强度指标，作为不分离接触弹塑性有限元强度折减算法中滑面带上接触单元的抗剪强度指标；然后，采用该算法分析强降雨作用下的浅层滑坡稳定性，通过建立的数理统计相关式计算滑坡的稳定性系数，为该类型浅层滑坡稳定性分析和较准确地预报提供更加可靠和充分的依据。研究结果揭示了强降雨对浅层滑坡变形解体和破坏的作用机理，表明强降雨是诱发浅层滑坡的最关键因素。

ANALYSIS OF SHALLOW LANDSLIDE STABILITY UNDER INTENSIVE RAINFALL

Based on actual survey data, the results of indoor physico-mechanical test and engineering practice, the relationship among safety factor of slope, shear strength index and saturation-area ratio of slope-mass under intensive rainfall was researched; furthermore, their mathematic statistics related expression was established. According to this related expression, difficulty in analyzing stability of shallow slope under intensive rainfall by the strength reduction limiting equilibrium method of non-separation contact elastoplastic finite element was discussed. The results are shown as follows. First, with making full use of the mathematic statistics related expression established and selecting different saturation-area ratios of slope-mass, corresponding equivalent shear strength index of slide plane under intensive rainfall is obtained, which acts as the one of contact elements on slide plane in the strength reduction arithmetic of non-separation contact elastoplastic FEM. Second, the stability of shallow slope under intensive rainfall may be more accurately analyzed by the above method, which may more clearly reflect actual state of slope disintegration, deformation and failure. Third, the results may afford more reliable and adequate bases on calculation of the safety factor and analysis of slope stability; meanwhile, according to different saturation-area ratios of slope-mass, more accurate forecast of this type of shallow landslide may be carried out more conveniently by the above method. Fourth, the mechanism of disintegration, deformation and failure of shallow landslide under intensive rainfall is revealed. Furthermore, it is confirmed that intensive rainfall is the most decisive triggering factor that leads to sudden instability of shallow landslide.