Study On The Mechanism Of Water-Rock Interaction And Stability Analysis Under Rainfall And The Fluctuation Of Reservoir Water Conditions For Reservoir Landslides

Reservoir landslide is a severe geological hazard which is caused by the reservoir water-rock interaction in reservoir area. Rainfall and the fluctuation of reservoir water are the master factors which effect on the stability of landslides. Numerical analysis of the reviving mechanism of landslide is important to the forecast and reinforce of reservoir landslide.Maoping landslide, one of the most typical large-scale bedding bedrock reactivated old landslide in the Geheyan reservoir area of Qingjiang river, has multilevel and repetitions sliding characteristic. The latest ten years monitoring dada of which indicated that significant deformation has appeared since the dam impounded water on April 10, 2007 ,an then evolved to globe slide step by step, the large deformation of the slide has over 2100 millimeter by now, furthermore, the deformation still in developing stage, once the landslide becomes instable, severe disaster will occur.In this paper, the Maoping landslide is as a case for research. Based on detailed geological investigate and monitoring data analysis, a geological model has been abstracted. Finite element model for static analysis and saturate-unsaturate seepage-stress couple computation has been established, and penetrate coefficient and material mechanical parameters of landslide were carried out through back analysis with BP neural network and Genetic Algorithms, of course, before back analysis the target parameters were chose by sensitivity analysis. With parameters which from back analysis and unsaturated seepage-sress coupling computing model, the deformation mechanism of landslide under different conditions, such as, fluctuation of reservoir water and rainfall penetrating were analyzed. Finally, based on the parameter study of ABAQUS, the shear strength coefficient reduction in-step become true, through the finite element strength reduction coefficient method, the landslide stability before and after the reservoir impounding water were evaluated.From the detail analysis of landslide monitoring data and the back analysis of material parameter, and also the numerical simulation for landslide deformation under the hydrodynamic effect and the last stable evaluation of landslide, which reflect the mechanism of water-rock physic-dynamic interaction., The whole analysis from qualitative stage to quantitative stage formed a systemic way on the deformation mechanism and stable evaluation method of landslide, therefore, the product of this paper may provide scientific bases for the treatment of landslide on certain degree.