基于解析法的隧洞施工对地下水环境影响预测

Impact analysis of tunnel construction on groundwater environment by analytical method

涌突水是岩溶隧洞工程建设中经常会遇到的一个突出性问题。以滇中引水工程玉溪红河段(新庄-蒙自)的小扑隧道为例,介绍地下水环境影响评价过程,提出分段运用解析法对其20个桩段进行涌水量预测。主要采用大气降雨入渗法和地下水动力学法预测正常涌水量,采用地下水动力学法预测最大涌水量。结合现场调查发现施工区内有溶洞、落水洞、暗河,隧洞施工过程中可能袭夺暗河地下水导致较大涌突水灾害发生。根据解析和现场调查结果,提出了科学合理的防治对策和工程措施,以规避可能的重大地下水环境影响。

Water gushing is a prominent problem frequently encountered in karst tunnel construction.In the case of Xiaopu tunnel in Honghe section in Yuxi City(from Xinzhuang to Mengzi)of Central Yunnan Water Diversion Project,this paper introduces the assessment process of underground water environment impact,and suggests a segmented prediction for water gushing in 20 canal sections by analytical method.The normal water gushing is predicted mainly by rainfall infiltration method and groundwater dynamics method and the maximum water gushing is predicted by groundwater dynamics method.The geological survey discovered karst caves,sinkholes,underground river channel in the construction area.The construction tunnel may take over underground rivers in the construction process and cause severe gushing disaster.According to the analytical and field investigated results,reasonable control countermeasures and structure measures are put forward to avoid the possible severe groundwater environment impact.