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云南省绥江县汤家山滑坡为一由冲、洪积物组成的松散堆积层滑坡。以该滑坡滑带土为主要研究对象,通过野外调查和室内试验,对滑带土的物理性质、微观结构和形成机理进行了分析研究。结果表明:滑坡体的物质成分为砾石、砂、粉砂和粘土,而滑带土主要由粉砂和粘土矿物组成,该滑坡为典型的松散堆积层—基岩接触面滑坡;与滑坡体物质相比,滑带土具有粒度明显变细、含水量变小和密度增大的特点;滑带土边界发育的微孔隙和微裂隙为地表水的入渗提供了有效通道;滑带土的粉粒和粘粒具有明显的定向排列特征,滑带表面发育有两组线形擦痕,反映该滑坡体局部可能发生过至少两次滑动。滑带土的整个力学行为可以概化为排水条件下正常固结土发生了首次剪切变形,后期在边坡开挖和降雨的联合作用下老滑坡体局部沿原有剪切面又产生了二次滑动。
The Tangjishan landslide in Suijiang County, Yunnan Province is a loosely accumulated landslide consisting of red and flood sediments. Taking the landslide slippery soil as the main research object, the physical properties, microstructure and formation mechanism of the slippery soil are analyzed through field investigation and laboratory tests. The results show that the material composition of the landslide body is gravel, sand, silt and clay, while the landslide soil is mainly composed of silt and clay minerals. The landslide is a typical loose accumulation-bedrock contact surface landslide; In contrast, the slip-zone soil has the characteristics of obviously smaller particle size, smaller water content and higher density. Micro-pores and micro-fractures developed on the boundary of slip-zone soil provide an effective channel for infiltration of surface water. And clay particles have obvious directional arrangement characteristics. There are two sets of linear scratches on the surface of the sliding belt, which indicate that there may be at least two sliding parts in the landslide body. The whole mechanical behavior of slippery soil can be generalized as the first shear deformation of normal consolidated soil under drainage conditions. In the later stage, the old landslide body was partially produced along the original shear surface under the joint action of slope excavation and rainfall Slide twice.