新干航电枢纽工程库区浸没数值分析与治理

Reservoir Immersion Effects by Numerical Analysis and Protection Measures Taken in Xingan Navigation and Hydropower Scheme

新干航电枢纽工程水库蓄水将引起大范围的渗漏浸没。根据区域水文地质情况建立区域有限元渗流模型,求解区域渗流场,揭示了区域渗流分布规律。基于有限元法和平面解析法分别圈划的浸没区形态基本一致,但有限元法计算出的浸没面积较平面解析法少了12%。通过区域渗流数值仿真分析,对浸没治理方案试算和选优。增加防渗墙时,防渗墙集中了水力坡降,区域地下水位得到了有效降低,浸没面积减少了62%,但仍不能满足设计要求。采用防渗墙和减压排水井联合治理时,进一步降低了地下水位,可以达到浸没治理的目的;同时验算了在洪水期高水位时,浸没治理方案的安全性。

After inundation of Xingan reservoir there will be an intensive leakage around the reservoir rim which is a hazard for cropping due to the rising aquifer level. To examine the potential influence of this groundflow, a seepage numerical model was created based on the finite element analysis method in conjunction with the regional hydrogeological setting. The result suggests that the seepage fields developed either by finite element method or 2 dimensional analytic method shown the similar in geometry, while the immersed area calculated by the former method is 12% less than the latter one. Through regional seepage numerical simulation analysis, the immersion treatment schemes have been trial and selected. If the diaphragm walls are increased, hydraulic gradient will be cut- off sharply and the regional ground water will be reduced effectively. Thus the immersion area will reduce 62%. However, the result still can't meet the design requirement. If relief wells and the diaphragm walls can be combined used, the ground water will be reduced further, and the immersion influence will be solved. Additionally, seepage stability has been checked by simulation analysis under the condition of flood high level, and the relief well scheme is proved to be safe.