锦屏二级水电站隧洞涌水的数值反演与预测

 锦屏二级水电站位于河间高山峡谷岩溶区，大规模隧洞群的开挖会显著改变地下水循环条件，形成隧洞涌水，辅助洞施工期间的涌水特征表明，锦屏山体存在12条陡倾导水裂隙带。利用MODFLOW建立5种工况下的三维稳定流模型，着重刻画对涌水起重要作用的导水裂隙带。以各涌水点的实测涌水量为拟合依据，使用UCODE数值反演软件对模型进行校正，关键参数得到优化，从而提高模型可靠度。参考辅助洞的防渗模式，模型预测防渗前后隧洞群的总涌水量分别为40.35和31.19 m3/s，隧洞开挖致使工程区内两大泉断流。泉水的恢复需要更有效的防渗措施。

INVERSE PROBLEMS AND PREDICTION OF WATER INFLOW IN TUNNELS OF JINPING II HYDROPOWER STATION

Jinping II hydropower station is situated in a karst area with mountains and valleys. The excavation of large size tunnels will significantly change the conditions for groundwater flow，causing inflow in the tunnels and impacts on surrounding environment. As indicated by the discharge patterns of groundwater in the auxiliary tunnel during its construction，12 fractured zones with high vertical conductivity are existing in the Jinping mountain. Five three-dimensional stead state flow numerical models are built with MODFLOW. In the models，these fractured zones are typically considered. UCODE is employed to calibrate the models according to observations of groundwater inflow，and key parameters are identified and optimized for better modeling. Based on the waterproofing technique in the auxiliary tunnel，the models predict water inflows in all tunnels before and after waterproof protections，and the results are 40.35 and 31.19 m3/s，respectively. Excavation of the tunnels will causes drying of two major springs in the area，and the springs could not be recovered unless more effective waterproof protection is applied.