坝基计算范围对均质土坝浸润线的影响

Effects of calculation scope of dam foundation to saturated line of homogeneous earth dam

【目的】基于稳定渗流理论,分析坝体与坝基不同渗透系数比值时坝基计算范围对浸润线的影响。【方法】采用理正渗流分析软件,对均质土坝坝体与坝基不同渗透系数比值下,不同地基计算范围进行了数值模拟,并运用ABAQUS软件验证模拟结果的可靠性。【结果】在浸润线计算中,对于均质土坝,当坝体与坝基渗透系数的比值≥10时,可以按不透水坝基进行计算;分析浸润线时,坝基的计算宽度沿上游延伸长度建议取1～2倍坝高即可满足精度要求,但对于渗流量计算,此判断标准不适用。【结论】均质土坝处于稳定渗流状态时,坝基计算范围对浸润线的影响仅与坝体、坝基渗透系数的比值有关;随坝体、坝基渗透系数比值的增大,坝基有效计算深度逐渐减小。

[Objective] Based on steady seepage theory, the change of the saturation line in different base zones was investigated. [Method] Numerical simulation of the saturated line of different base zones with different permeability coefficient ratios was conducted using leading software. And the simulation result was validated by ABAQUS software. [Result] The dam base can be considered as impermeable when the permeability coefficient was less than 1/10 of the dam body for saturation line calculation. To satisfy the requirement of accuracy,the calculation length along dam upstream was recommended to be 1--2 times of the dam height. Above conclusions are not adapted for leakage flow calculation. [Conclusion] The influences of dam foundation calculation range to saturation line were only related to the ratio of permeability coefficients of dam body to dam foundation when the seepage of homogeneous earth dam was stable. The bigger the ratio is,the smaller the effective depth would be.