土石坝饱和砂土地基地震液化及加固措施数值模拟研究

为研究不同库水位及土石坝上下游坝脚有无设置压重对地震作用下饱和砂土坝基可液化土层的影响规律,以某中型平原水库土石坝为工程背景,利用岩土软件Geo-slope模拟分析了不同工况下坝基可液化土层的液化分布规律、坝体典型节点的加速度响应及上下游坝坡的稳定性。计算结果表明,正常蓄水位下,上下游坡脚设置压重后,坝脚处的液化区域明显减小,但远离上下游坝脚处的可液化土层的液化范围较无压重情况下几乎无改变。死水位情况下,上下游坡脚设置压重后可液化土层的液化区域变化规律与正常蓄水位下相似,但上下游远离坝脚处的可液化土层液化面积较无压重情况下相差无几,上下游坝坡的稳定性较为一致,但设置压重一定程度上增加了坝坡的稳定性。坝体的典型节点处的加速度出现不同的放大效应,其中坝顶的放大倍数最大,出现鞭梢效应。

Numerical Simulation of Seismic Liquefaction and Reinforcement Measures for Saturated Sand Foundation of Earth-Rock Dam

In order to study the influence of different reservoir water levels and pressure on the liquefaction layer of saturated sand dam foundation under earthquake, a medium-sized plain reservoir earth-rock dam is taken as the engineering background. Using the geotechnical software Geo-slope, the liquefaction distribution law of the liquefied soil layer of the dam foundation under different working conditions, the acceleration response of the typical joints of the dam body and the stability of the upstream and downstream dam slopes are simulated. The results show that under the condition of normal storage water level, the liquefaction area at the foot of the dam is obviously reduced when the pressure is set at the foot of the upstream and downstream slope, but the liquefaction range of the liquefied soil layer far from the foot of the upstream and downstream dam is the same as the case without pressure. Under the condition of dead water level, the liquefaction area of the liquefied soil layer is similar to that of the normal storage level after the pressure is set at the foot of the upstream and downstream slope, but the liquefaction area of the liquefied soil layer far from the dam foot in the upper and lower reaches is almost the same. The stability of upstream and downstream dam slope is consistent, but the stability of dam slope is increased to a certain extent by setting pressure. The acceleration at the typical joints of the dam has different magnification effects, in which the magnification of the dam top is the largest and the whip effect appears.