易侵蚀层厚度对滑坡运动过程与堆积特征影响的模型试验研究

Model test study on the influence of the depth of erodible layer on landslide movement process and deposits morphology

为研究滑坡与易侵蚀层相互作用下产生的地质构造现象,利用砂盒试验装置对滑坡的运动过程进行研究,揭示滑体运动过程中速度场与位移场规律,剖析滑坡堆积体几何形态及内部构造特征。结果表明:滑体运动过程分为3个阶段,初始阶段,滑体沿斜板下滑,速度和加速度快速增加;加速、稳定阶段,易侵蚀层会极大地抑制滑体的运动,滑体与易侵蚀层碰撞后速度与加速度瞬间降低,使得滑体位移量显著减小;随着易侵蚀层厚度的增加,滑体在撞击易侵蚀层后速度减小的幅度增大,堆积体面积、长度随厚度的增加而逐渐减小;在易侵蚀层厚度增加的过程中,滑体对易侵蚀层的作用形式逐渐由挤向覆转变,作用过程变得复杂;随着厚度的增加,相互作用变得复杂,堆积体内部发育直立褶皱、平卧褶皱、逆冲剪切、水平剪切、包卷等结构,表面形成褶皱、隆起等构造,反映滑体从压缩到剪切运动的应力状态。研究结果为滑坡运动路径中存在易侵蚀时的灾害范围计算提供了一定的理论参考。

To study the geological structure phenomenon under the interaction between landslide and erodible layer,the movement process of landslide is studied by using sand box test device,and the law of velocity field and displacement field in the movement process of landslide is revealed,the geometric shape and internal structure characteristics of landslide deposits are analyzed.The results show that the motion process of the sliding mass can be divided into three stages:initial stage,when the sliding mass slides along the inclined plate,the velocity and acceleration increase rapidly.In the acceleration and stabilization stages,the existence of the erodible layer will greatly inhibit the movement of the sliding mass,and the velocity and acceleration of the sliding mass immediately decrease after the collision with the erodible layer,resulting in the significant decrease of the sliding body position shift.With the increase of the depth of the erodible layer,the velocity decrease of the sliding mass after impacting the erodible layer increases.Meanwhile,the area and length of the deposits will gradually decrease with the increase of the depth.As the depth of the erodible layer increases,the action form of the sliding mass on the erodible layer gradually changes from squeezing to overlying,and the action process becomes complicated.With the increase of the depth,the interaction becomes complicated.The internal structure of the deposits develops upright fold,recesses fold,thrust shear,horizontal shear,enveloping and other structures,and the surface forms fold and uplift,which reflects the stress state of the sliding mass from compression to shear movement.The research results provide a theoretical reference for the calculation of disaster scope when the erasion tends to emerge in the landslide movement path.