粗砂滑坡离心模型试验及离散元细观模拟

为了探明砂土滑坡的力学机理，采用自行研制的降雨诱发滑坡离心模型试验装置，进行粗砂滑坡离心模型试验，基于试验结果，采用改进后的离散元数值模拟程序对滑坡过程进行细观研究，从细观和非饱和角度对离心模型试验进行补充。研究结果表明：粗砂滑坡发生的细观机理为坡体中的水无法及时排出，导致土颗粒悬浮在水颗粒中，土颗粒间的接触减少甚至脱离，土颗粒间的相互作用力转化为土颗粒与水颗粒之间的作用力，土体出现流体特征，抗剪强度丧失。滑坡的发展表现为两种可能的形式：各处水颗粒施加给土颗粒的作用力与此位置土颗粒的接触力正好相等，表现为整体滑动；水颗粒施加给土颗粒的作用力等于土颗粒重力和前部土颗粒的接触力之和，表现为后部滑坡向前部发展。

Centrifugal model test of coarse sand landslide and discrete element mesoscopic simulation

To explore mechanic texture of sand landslide ,a centrifuge modelling test device for rainfall induced landslide was developed to carry out coarse sand centrifuge model test. Based on the test results, the improved discrete element numerical simulation program is used to study the meso scale process of landslide, and the centrifuge model test is supplemented from the perspective of meso scale and discontinuity. The results show that: the meso mechanism of coarse sand landslide is that the water in the slope cannot be discharged in time, resulting in the soil particles suspended in the water particles, the contact between the soil particles is reduced or even separated, the interaction between the soil particles is transformed into the interaction between the soil particles and the water particles, the fluid characteristics of the soil appear, and the shear strength is lost; There are two possible forms of landslide development: the force exerted by the water particles on the soil particles is exactly equal to the contact force of the soil particles at this position, which shows the overall sliding; The force exerted by the water particles on the soil particles is equal to the sum of the gravity of the soil particles and the contact force of the front soil particles, which shows that the rear landslide develops forward.