Transient groundwater seepage field simulation of slope and its stability analysis influenced by reservoir water level fluctuation

摘要

Reservoir water level fluctuation is the direct inducement of many large-scale rock slope failure. Taken Xirangpo, the rock slope in Badong County in the Three Gorges reservoir area as an example, finite element method is used to simulate the transient groundwater seepage filed of the slope influenced by the reservoir water level fluctuation in a whole hydrological year. The distribution of groundwater level obtained from transient simulation is used to limit equilibrium analysis. Considering the three phases of adjustment of the reservoir water level: water level increasing from 145 m to 175 m, keeping constant at 175 m, decreasing slowly from 175 m to 145 m, the safety factor of slope has been calculated. Results show that the safety factor decreases when reservoir level increases from 145 m to 175 m, and it continues to decrease when the reservoir level keeps at 175 m and it increases again when the reservoir level decreases from 175 m to 145 m. However, the safety factor t in the third phase can not reach one in the first phase and there is a small loss. This paper indicates the cause of many large-scale rock slope failure after times of reservoir level fluctuation.