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滑带土是滑坡形成过程中形成的一层结构性较差的土体,是滑坡的重要组成部分。其物理力学性质、微观结构与滑坡的形成以及后期运动特征密切相关。黄土-泥岩接触面滑坡是按照滑坡地质成因划分的一种上层黄土、下层泥岩的具有“双层异质”结构的滑坡。此类滑坡由于在滑动中具有缓动低速的特点,往往早期不易被发现,发现时已造成了严重的危害。采用GDS三轴仪对天水地区花南村滑坡、半山村滑坡和咀头村滑坡三个黄土-泥岩接触面滑坡的滑带土力学性质进行研究,结合滑带土微观结构特征,分析黄土-泥岩接触面滑坡滑带土的力学变化特征及其变形内在机理。研究发现:滑带土中大量存在被黏土颗粒包裹的大颗粒,这些大颗粒在滑带土变形过程中经历错位、滑移等过程后,大颗粒进一步滑移受到黏土质限制,导致黄土-泥岩接触面滑坡滑带土在宏观上表现出应变硬化的典型特征。此外,剪切中孔隙水压力无法及时消散也是此类滑坡变形的重要特征之一。应变硬化造成滑带土在滑动中强度未出现残余值而导致滑坡处于持续运动中,能量的释放方式属于缓慢释放型。因此该类滑坡滑动具有缓动低速的特性。
Landslide soil is a layer of poorly formed soil formed during the landslide formation and is an important part of the landslide. Its physical and mechanical properties, microstructure are closely related to the formation of landslides and the characteristics of later movement. Loess - mudstone contact surface landslide is a kind of landslide with “double heterogeneous” structure of upper loess and lower mudstone according to the geologic cause of landslide. Such landslides tend to be hard to find early because of their slow slow moving speed, which has caused serious damage. The mechanical properties of the landslides of the Loess-Mudstone landslides in the Huaxiancun landslide, the Banshancun landslide and the Tsuitoucun landslide in the Tianshui area were studied by using the GDS triaxial apparatus. Combined with the microstructure characteristics of the landslide soil, the effects of the loess-mudstone contact Mechanical Change Characteristics of Sliding Zone Soil and Its Deformation Internal Mechanism. It is found that there are a large number of large particles in the slippery zone soil, which are surrounded by clay particles. These large particles undergo misalignment and slippage during the deformation of the slip zone so that the further slippage of large particles is restricted by the clay, resulting in the formation of loess-mudstone Landslide slippery zone soil shows the typical characteristics of strain hardening macroscopically. In addition, the shear pore water pressure can not be dissipated in time is also one of the important features of landslide deformation. Strain hardening causes no residual value of slippery soil in the sliding strength, resulting in continuous movement of the landslide. The energy release mode belongs to the slow release type. Therefore, this kind of landslide sliding slow slow down characteristics.