基于滑弧动力有限元耦合法的高土石坝坝坡稳定性分析

为研究高土石坝坝坡的稳定性,以某水电站高土石坝坝坡为例,采用条分法与有限元法耦合的计算方法进行分析,选取3个典型断面,对其设计工况和校核工况下的上下游断面的安全系数进行计算。计算结果表明:(1)下游坝坡最小安全系数比上游大,设计工况安全系数比校核工况安全系数大;(2)3个断面在各工况下取得最小值的时刻近似,符合坝坡稳定的计算规律;(3)经过动荷载分析,大坝坝坡在设计地震动作用下是稳定的,考虑到高坝的"鞭鞘效应",建议在河床中部坝段坝高4/5以上区域采取适当的抗震措施,如加密钢筋、加大堆石粒径、采用胶结堆石料、坝坡加护面层等。研究结果表明,采用条分法与有限元法相结合的方法评价高土石坝坝坡的稳定性,比单一评价方法更科学、可靠。

Slip-circle dynamic finite element coupling method-based analysis on stability of high earth-rockfill dam

In order to study the stability of the slope of high earth-rockfill dam，the slope of the high earth-rockfill dam for a hydropower station is taken as the study case and then is analyzed through the slices method and finite element coupling method; for which three typical cross-sections are selected for calculating the safety factors of both the upstream and downstream cross-sections under both the operation condition and the checking condition． The calculation results show that ( 1) the minimum safety factor of the downstream dam slope is larger than that of the upstream one，while the safety factor of the design operation is larger than that of the checking condition; ( 2) the moments for getting the minimum values of the three cross-sections under all the operation conditions are approximate and consistent with the law of calculating the slope stability; ( 3) through the relevant dynamic load analysis，the slope of the dam is stable under the design earthquake effect，however，under the consideration of the whiplash effect of high dam，it is suggested to adopt suitable seismic measures for the zone above 4/5 of the dam section within the middle part of riverbed，such as reinforcement，enlarging the particle size of rock-fills，adopting cementing rockfill materials，adding surface protection layer for the dam slope，etc．． The study result shows that evaluating the slope stability of high earth-rockfill dam with the combination of slices method with finite element method is more scientific and reliable than that evaluated with a single method．