中文摘要：

近年来西部公路建设突飞猛进，而公路沿线滑坡灾害也频繁发生，因此有必要对其深入研究并进行相应的工程治理。基于藏东南妥坝3^#滑坡的现场勘察、测试及室内试验，通过工程地质分析、有限元强度折减、敏感性分析、模拟开挖等多种方法，对该滑坡各种特征、成因及其稳定性因素进行了综合研究。结果表明：该滑坡体物质为多层堆积碎石土，滑带位于相对软弱的角砾土或粘性土含量较大的碎石土中；其运动特征为间隙性的牵引式低速滑动；滑带土抗剪强度参数、地下水位、坡脚开挖等是影响滑坡稳定安全的敏感因素；区域构造、地形及地层特征是滑坡发生的环境因素。滑坡成因为：坡脚开挖、河流侧蚀使临空面增大，改变了滑坡体的边界及荷载状态，坡体前缘应力集中，使边坡在重力的作用下失稳滑移，牵动坡体后部移动。高强度降水、季节性冻土融化造成坡体内地下水富集，含水范围扩大，地下水位抬升，增加了滑体的重量，软化滑带土层，降低了滑动面（带）的抗滑力，加剧了滑坡的形成和解体。

英文摘要：

With the recent advancement of highway construction, the landslide disasters alongside the lines occur frequently; deep-going research and engineering control of these landslides have value practical value. Based on field investigation, field and indoor tests of Tuoba landslide No. 3 in Southeast Tibet, the geological analysis, finite element strength reduction analysis, sensitivity analysis and excavation simulation methods were used comprehensively to study the characteristics, cause and stability of these landslides. The result shows that： （ 1 ） the slide mass is multi-layer accumulation gallet; （2） slide mass is located in the relative fragile gallet which have a high content of gravel and silt; （3） the slide＇ s movement was characterized as slow velocity traction slide; （4） sliding mass＇ s shear strength, level of underground water and, slope toe excavation are the sensitive factors affecting slope stabili- ty ; （5） areal geological structure, topography and layer trait are the environmental factors of landslide. The evolution of landslide is as follows ： once the toe of slope was excavated its free surface＇ s is enlarged by river＇ s side etching; as a result the slide mass＇ s boundary load status is changed, concentrated stress appears in the front ofslope, the slope lost its stability and began to slide under the condition of gravity, and the back part of slope is excluded to move. Heavy rainfall, seasonal frozen soil＇ s melting leads to the concentration of underground water in the inner part of the slope; the scope of water enlarged, the level of underground water rises and the increase of slope mass weight and the softening of sliding zones layer decrease the sliding zone＇ s anti-slide strength, accelerate the landslide＇s formation and disaggregation.