Analysis and numerical simulation of toppling deformation and failure characteristics of anti-dipping rock slope under impoundment

Abstract

High dam engineering is characterized by high water head, steep slope and complex geological conditions. Excavation or water storage will destroy the original equilibrium state of the bank slope and induce the deformation of the bank slope. Based on the monitoring data, this paper analyzes the spatio-temporal evolution of slope deformation during the impoundment of a reservoir bank in China. On this basis, considering the influence mechanism of water pressure, temperature, rainfall, seepage, rock mass rheology and other factors on slope deformation in the process of water impoundment, a statistical regression model of slope deformation is established, and the regression analysis of the deformation process of typical measuring points is carried out, and the main influencing factors of slope deformation are analyzed. Based on regression analysis, the slope deformation and failure process under impoundment are simulated and the influence degree of effective stress change and parameter weakening of rock mass on bank slope deformation and failure in the process of seepage field change is studied to reveal the main inducement of slope deformation under impoundment through the fractured rock mass seepage-stress-rheology coupling finite element analysis method. The results show that the slope deformation is the rheologic deformation triggered by the decrease of effective stress at slope toe caused by the rise of water level and the softening of rock mass, and the toppling form is the dominant one in space.