岩溶隧道工程修建对地下水环境的影响

岩溶地区隧道施工期涌突水危害巨大，而大量输排地下水又会引发一系列的地质灾害。对中梁山隧道水文地质进行分析，采用遗传算法优化BP神经网络并对渗透参数进行反演，研究了隧道工程不同埋深、排水量对地下水环境的影响规律，并探究了隧道施工期和运行期地下水环境随时间的演变规律。结果表明：富水岩溶地区隧道具有从隔水层到含水层界面处涌突水风险最大的特点；开挖隧道时隧道高程越低、排水量越大，地下水环境变化越大；隧址区降落漏斗呈现出南侧小于北侧、东侧小于西侧的特征。现有施工期排水条件下施工地下水位下降很快且不能恢复到原水位，建议该地区在隧道施工期控制排水量，并在施工期及运营期采取保护地下水环境的措施。

Impact of tunnel engineering on groundwater environment in karst area

During the tunnel construction in the karst area, there is a great danger of water inrush, and the discharge of groundwater will lead to the geological disasters. The hydrogeology in Zhongliang mountain tunnel area was analyzed and the BP neural network optimized by the genetic algorithm is used for inverse analysis of the permeability coefficient of aquifer. The impact of tunnel elevation and the discharge of groundwater on groundwater environment change was studied, and the groundwater environment change with time was explored. The results show that water inrush during karst tunnels construction is most likely to occur on the interface between the aquifuge and the aquifer, and that tunnel elevation and the discharge of groundwater have both great impacts on the groundwater environment. The results indicate that the groundwater level drops rapidly and cannot return to the original level in the current drainage conditions. Consequently the discharge of groundwater should be controlled properly during construction. Measures should be also taken to protect the groundwater environment during construction and operation stage of tunnels.