库水位上升条件下浮托减重型滑坡离心模型试验

为研究三峡库区浮托减重型滑坡复活变形特征，以木鱼包滑坡为原型，概化设计了大尺寸离心模型试验.运用高速相机、孔压和土压力传感器，获取了滑坡变形演化的高清影像、孔压和土压等数据，分析了库水作用下该类滑坡的变形特征和机理.研究结果表明:在库水位上升过程中，滑坡发生了两次明显变形.第一次变形时，中后部首先产生拉张裂缝，随后前部出现压应力集中和隆起现象，为典型推移式滑动.两次变形均经历了从初始变形到加速变形最后减速并停止的过程，累计位移呈典型的“阶跃状”特征.结合孔压和土压数据分析，滑坡变形主要受库水入渗产生的浮托力影响.滑体材料固结压密和衰减蠕变，以及下滑后势能损失是滑坡变形逐渐停止的主要原因.

Centrifugal Model Tests on Buoyancy-Induced Weight Loss Landslides Influenced by Rising Reservoir Water Level

In order to study the deformation characteristic of buoyancy-induced weight loss landslides subjected to the reservoir impoundment in the Three Gorges Reservoir Area， the large-scale centrifugal model test was designed based on Muyubao landslide. Through laying high-speed cameras and pore water pressure (PWP) and earth pressure (EP) transducers， the high-definition images of the model slope and the data of PWP and EP vs. time were obtained. The results show that during the first deformation process， the model has been deformed twice successively in the period of water level rising. Tension cracks appear in the mid-rear part firstly， and then compressive stresses consentrate and the uplifts appear in the front part，which is a push-type landslide. The model undergoes a process from initial deformation to accelerated deformation， decelerated deformation and then stopped ultimately. The cumulative displacements display an apparent step-like shape. According to the variation of PWP and EP， the reactivation of landslide is mainly caused by buoyancy force generated by reservoir water that infiltrating into the slope. Consolidation compaction and decreasing creep of sliding materials and potential energy loss after sliding are the main reasons for the gradual stop of landslide deformation.