Abstract: 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.

Key words: reservoir-induced landslide, buoyancy-induced weight loss, centrifugal model test, reservoir water level rising, deformation characteristics