LOAD-UNLOAD REPONSE OF COLLUVIAL LANDSLIDES WITH RESER-VOIR WATER LEVEL FLUCTUATION AND STABILITY PREDICTION

The stability of colluvial landslides in the Three Gorges Reservoir is obviously influenced by the fluctuation of water level. So studying the evolutionary process and stability prediction of colluvial landslides under the reservoir water level fluctuation is significant to provide references for disaster management and construction planning. The load-unload response prediction model in which reservoir water level was treated as the load-unload parameter and landslide displacement rate, as the load-unload response parameter was established. The model was based on the relationship between landslide deformation and reservoir water level fluctuation. And the type of landslide seepage field under the reservoir water level fluctuation was determined by revealing the relationship. Then the load-unload interval differences were evaluated by the rate of stability coefficient. Taking Huanglianshu landslide for example, the model was used to predict the development trend. The results show that the relationship between horizontal displacement of the landslide and reservoir water level fluctuation has an obvious hysteretic nature. The hydrodynamic pressure landslide has a loading process of six months and an unloading process of one month. The load-unload response ratio of monitoring sites raises and is more than 1. It reveals that the landslide will be instable and the load-unload response is more obvious due to reservoir water level fluctuation. The application results show that the prediction is well coincident with the macroscopic deformation evidence. Thus the improved model is feasible in the stability prediction of landslides.