水位升降对粘土心墙土石坝渗流稳定性分析

Analysis of seepage stability of earth-rock dam with clay core under ascending and descending water table conditions

利用非饱和非稳定渗流理论,对某粘土心墙土石坝在水位不同升降速度条件下的渗流场进行了数值试验,分别设计了从0.0 m开始以2.51、.5 m/d的水位上升速度蓄到88.0 m正常蓄水水位的计算工况,以及从88.0 m正常蓄水水位分别以8.0、4.0、2.0 m/d水位下降速度泄水至10.0 m最低水位的计算工况,计算了各工况下粘土心墙土石坝的渗流场,对比分析了水位升降速度对坝体渗流场的影响.基于上述渗流计算成果,分析了各工况下土石坝上游、下游面坝坡的稳定性,总结了坝坡最危险滑动面的时空演化规律和安全系数随水位升降速度的变化规律,为水库调水和日常管理提供了参考.

Using unsaturated and unsteady seepage theory, flow field of a earth-rock dam with clay core is numerically tested under different ascending and descending velocities of water level. Computing schemes with the ascending velocities of level being 2. 5 m/d and 1. 5 m/d storing up from 0. 0 m to 88.0 m （normal water level of the reservoir） is designed. Simultaneously, calculating plans with descending velocities of water level being 8.0 m/d, 4.0 m/d and 2.0 m/d discharging from 88.0 m to 10.0 m （lowest water level of the reservoir） are done. Flow fields of the earth rock dam under all com- puting conditions are simulated. Then, seepage fields affected by descending and ascending velocities of water level are compared each other. Based on these, the stabilities of upstream and downstream dam slope under all kinds of computing conditions are studied. Finally, time and space evolution law of slip surface and safety factor varying with the ascending and descending water level are summed up, so as to offer reference for optimal storing up and discharging water and management of the reservoir.