库水位升降联合降雨作用下库岸边坡中的浸润线研究

Analytic solutions for phreatic line in reservoir slope with inclined impervious bed under rainfall and reservoir water level fluctuation

库岸边坡中的地下水对其稳定性有重大影响,目前还没有统一的公式用来计算岸坡中的浸润线。为此,建立隔水底板呈缓倾角的均质岸坡模型,采用稳定渗流情况下的浸润线作为非稳定渗流的初始值,推导出库水位升降联合降雨作用下该模型中浸润线的近似解析解。利用Geo-Slope中的SEEP/W程序,对浸润线的近似解析解进行验证分析,结果表明,在不同库水位升降和降雨的组合条件下,由近似解析解确定的浸润线与数值模拟结果基本一致。对库水位升降联合降雨作用下赵树岭滑坡中的浸润线进行研究,利用实测浸润线验证了近似解析解的正确性,并预测了赵树岭滑坡在快速蓄水、快速蓄水+暴雨、快速泄水及快速泄水+暴雨4种工况下(库水位波动范围为145～175m)浸润线的变化情况。最后,从解析解的适用条件出发剖析了近似解析解误差产生的原因,为应用浸润线解析解解决实际问题提供依据。

Groundwater plays a significant role in the stability of reservoir slopes. However, there are no general formulas for the calculation of phreatic line. A conceptual model is established based on the reservoir slopes with inclined impervious bed; and the approximate analytic solutions of phreatic line caused by reservoir water level fluctuation and rainfall are derived with the initial value calculated in steady flow condition. The seep/w program of Geo-Slope analysis software is used to verify the approximate analytic solutions; and the results show that the phreatic lines calculated by approximate analytic solution are consistent with the simulation ones in different combination conditions of rainfall and reservoir water level fluctuation. Applying the approximate analytic solutions in the research of phreatic lines in Zhaoshuling Landslide, the effect is satisfactory. The analytic solution has been verified by measured phreatic line and then it is used to predict the different phreatic lines under the conditions of rapid reservior impounding, rapid reservior impounding together with rainstorm, rapid reservior flushing and rapid reservior flushing together with rainstorm （fluctuation range of water level is 145 m to 175 m）. The reasons which caused the error of approximate analytic solutions are analyzed thoroughly; and it would provide a basis for better use of approximate analytic solutions of phreatic line in practice.