库水位升降对那板心墙土石坝渗流场及坝坡稳定性的影响

Influence of Ascending and Descending Water Level on Seepage Field and Stability of Naban Core Earth-rock Dam

以那板心墙土石坝为例,基于多孔介质饱和—非饱和渗流基本原理,采用有限元方法对该坝在不同库水位升降速度条件下的瞬态渗流场进行了数值模拟,并将瞬态渗流场与极限平衡法相结合分析了坝坡的稳定性。结果表明,坝体渗流场的变化相对于库水位的变化具有明显的滞后性,该滞后性对库水位快速下降条件下的上游坝坡的稳定极为不利,而对库水位快速上升条件下的上游坝坡的稳定有利,为库水位变化对土石坝渗流场及坝坡稳定性分析评价提供了参考依据。

Based on the theory of saturated-unsaturated unsteady seepage of porous media and finite element method,the transient seepage field of Naban core earth-rock dam is numerically tested under different ascending and descending velocities of reservoir water level.The computed transient pore water pressures are then used for subsequent limit equilibrium analysis of the slope stability.The results show that the variation of seepage field lags behind that of reservoir water level,which is unfavorable to the upstream dam slope stability under the drawdown reservoir water level condition,but is good to the upstream dam slope stability under the rising reservoir water level condition.The simulation results provide basis for analyzing transient seepage filed and slope stability of dam in the conditions of ascending and descending water level.