持续强降雨引发水位耦合变化条件下堤防渗流及稳定性分析

针对江、河、湖泊土质堤防工程在持续强降雨下会导致堤前水位显著变化而可能引发堤防安全隐患,采用水-气二相非饱和渗流模型对堤防进行降雨入渗和堤前水位变化耦合条件下的饱和-非饱和渗流分析。分别开展降雨入渗、堤前水位上升及持续强降雨耦合堤前水位上升过程的非稳定渗流有限元仿真分析。在此基础上对堤坡进行抗滑稳定分析,同时考察堤前水位变化及降雨过程中气相和基质吸力对堤坡稳定性的影响。计算结果表明:与单纯的降雨和水位上升相比,降雨耦合堤前水位上升会使堤身渗流及堤坡抗滑稳定性呈现较复杂的变化特性;考虑气相和基质吸力在一定程度上对堤坡稳定分析结果有利。

Analysis of dike seepage and slope stability under coupled conditions of continuously heavy rainfall and consequent change of water level

In dike engineering projects for rivers and lakes, continuously heavy rainfall will lead to a significant change in the water level, which may cause safety hazards to dikes. To solve these problems, a water-gas two-phase unsaturated seepage model was used to analyze the saturated-unsaturated seepage of a dike under the coupled conditions of rainfall infiltration and water level change. Finite element simulation was performed to study the unsteady seepage in the processes of rainfall infiltration, water level rise in front of the dike, and coupling of continuously heavy rainfall and the water level rise. On these bases, anti-sliding stability analysis of the dike slope was conducted, with consideration of the effects of the dike water level changes, and the gas phase and matric suction during rainfall on the slope stability. The results show that, compared to the rainfall infiltration or the water level rise, the coupled conditions of rainfall and the water level rise will cause the seepage and slope stability of the dike to become more complex. Considering the gas phase and matrix suction will be helpful to slope stability analysis.