水位变化对路基边坡渗流场及稳定性影响分析

Analysis of Influence of Water Level Change on Seepage Field and Stability of Subgrade Slope

针对蓄滞洪区路基边坡因洪水水位上升、持续、下降过程导致路基边坡失稳破坏的情况,通过室内模型试验来模拟洪水对路基边坡的作用过程,并结合GEO-Studio(SLOPE/W和SEEP/W耦合)程序建立了等效的介质连续模型;基于饱和-非饱和渗流理论及极限平衡法,探究洪区路基边坡在水位变化过程中的孔隙水压力变化、浸润线动态变化以及安全系数变化规律。结果表明:室内试验与模型仿真的孔隙水压力以及体积含水量变化规律一致;涨水阶段浸润线随水位上升而上升,浸泡阶段浸润线向边坡内部发展,退水阶段浸润线随着水位的降低而逐渐下降;水位变化过程中边坡稳定性随水位上升而增加,在浸泡阶段稳定性降低,在退水阶段稳定性迅速下降。

In view of the instability and failure of embankment slope caused by the rising,continuing and falling of flood water level in flood storage and detention area,the process of flood on the embankment slope was simulated through indoor model test.Combined with GEO-Studio(coupling of SLOPE/W and SEEP/W)program,an equivalent medium continuity model was established.Based on the saturated-unsaturated seepage theory and limit equilibrium method,the changes of pore water pressure,dynamic changes of phreatic line and safety factor of embankment slope in flood area were studied.The results show that the variation of pore water pressure and volume water content of indoor test and model simulation are consistent.The phreatic line would rise with the rise of water level in the rising stage,develop to the inside of the slope in the soaking stage,and gradually decreases with the decrease of water level in the recession stage.During water level change,the slope stability increases with the rise of water level,decreases in the soaking stage,and decreases rapidly in the water withdrawal stage.