库水位骤降偶遇地震作用下黏土心墙坝渗透及抗震稳定性分析

利用岩土软件Geostudio,根据非饱和渗流原理,以四方井水利枢纽中的黏土心墙土石坝为背景,分析了库水位骤降偶遇地震作用下黏土心墙土石坝上下游坝坡渗流特性及抗震稳定性。计算结果表明:库水位下降速率越大,上游坝坡的孔压力变化越剧烈,安全稳定系数越小;监测点位置越高,孔压越难以达到稳定值。对于下游坝坡而言,孔压力变化相对平缓,监测点距离地下水位越远,孔压越难以稳定,孔压力响应库水位骤降的时间越长;库水位骤降至死水位情况下发生地震时,库水位骤降速率越大,上游坝坡安全系数越小,Newmark位移越大。下游坝坡的安全系数对于骤降速率不敏感,安全系数基本一致,Newmark位移非常接近。研究成果可为实际工程管理运行提供一定的参考。

Analysis of seepage and anti-earthquake stability of clay core dam under rapid drawdown and sudden occurrence earthquake

According to the principle of unsaturated seepage and taking the clay core wall earth-rock dam in Sifangjing Water Conservancy Project as the research object, the seepage characteristics and anti-earthquake stability of the upstream and downstream dam slopes of the clay core earth-rock dam under the accidental earthquake of sudden drop of reservoir water level was simulated and analyzed. The calculation results showed that the greater the rate of water level drops, the more severe the pressure of the upstream dam slope is, the smaller the coefficient of safety stability is. The higher the location of the monitoring point is, the more difficult it is to reach the stable value of the pore pressure. For the downstream dam slope, the change of pore pressure is relatively gradual, the farther away from the groundwater level, the more difficult it is to stabilize the pore pressure, and the longer the response time of pore pressure to respond to the sudden drop of reservoir water level. When the reservoir water level drops suddenly to the dead water level, the larger the sudden drop rate, the smaller the safety factor, and the larger the Newmark displacement. The safety factor of downstream dam slope is not sensitive to the plummeting rate, and the safety factor is basically the same, and Newmark displacement is very close. The research results can provide some reference for the actual project management and operation.