软弱基座型斜坡变形破坏机制模拟研究  

FAILURE MECHANISM OF SLOPES WITH SOFT BASE FROM NUMERICAL SIMULATION

作　　者：兰志勇[1] 赵建军[1] 翟崇 李俊杰[1] 龚凌枫 

机构地区：[1]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059

出　　处：《工程地质学报》2014年第3期421-427,共7页Journal of Engineering Geology

基　　金：国家自然科学基金(41102190)资助

摘　　要：软弱基座型斜坡崩滑在我国西南山区及三峡库区是一种较为常见的地质灾害。下伏软岩在上部硬岩重力作用和外营力地质作用下产生压缩变形,向临空方向塑性流动,导致上部硬岩拉裂,进一步发展演变为崩滑。贵州某斜坡为一典型缓倾内软弱基座斜坡,上部为灰岩形成高度约150m陡崖,下部为厚度大于150m泥岩形成的缓坡。调查发现上部硬岩坡肩部位产生多条深大拉裂,坡肩局部发生过多次崩塌落石现象,斜坡变形仍在继续。本文采用有限元数值模拟和底摩擦物理模拟相结合的方法,分析了该斜坡坡体内应力、变形分布特征和发展过程,在此基础上研究软弱基座型斜坡的变形破坏机制,为软弱基座斜坡崩滑地质灾害防治提供理论支撑。研究结果表明,缓倾内具软弱基座的斜坡变形破坏机制表现为压缩(塑流)—拉裂—剪断三段式滑坡。Collapses and landslides in slopes with soft base are very common geologic disasters in southwestern mountain regions and the Three Gorges reservoir area of China.They are harmful.The upper hard rock weight,the weathering and water softening and the underlain by soft rock base can generate compression and horizontal plastic flow towards the free face.Therefore,the upper hard rock can generate tensile cracks.Ultimately they lead to collapses and landslides.A slope in Guizhou is examined.Its upper part has a height of about 150m and is a limestone cliffs.Its lower part has a thickness greater than150m and is a shale gentle slope.It is a typical slope of a gently inclined ramp within the weak base.This paper uses the finite element numerical simulation and bottom friction method of combining physical simulation.It analyses the slope of the body stress,deformation distribution and development process.Based on this model,the paper studies the weak base of slope and its deformation and failure mechanisms and provides the theoretical support for the weak base slope of geological disasters protection. The results show that the slope deformation and failure mechanisms dipping the base are of the three performance of a compressed plastic flow,tension crack and shear-cut.

关 键 词：软弱基座 有限元分析 底摩擦试验 滑坡 

分 类 号：P315[天文地球—地震学] P642.21[天文地球—固体地球物理学]