岩溶隧道涌水来源及对地下水环境的影响

以萍乐坳陷带一座典型岩溶涌水隧道为研究对象,通过区域水文地质调查和物探查明了隧道涌水的主要来源;通过示踪试验和动态监测研究了隧道涌水对周边地下水环境的影响。结果表明:在向斜轴部沿小江边组和茅口组接触带发育东西向岩溶强径流带并接受西侧岩溶槽谷地表水补给是DK1764+490—DK1764+510段隧底涌水的主要来源;鸡足寺暗河在隧道施工后部分通道和流向发生改变,但依然可以通过隧道东侧岩溶洼地接受降水补给,因此雨季可以恢复部分流量;隧底注浆封堵涌水通道效果较好,同时对向斜轴部岩溶水强径流带影响轻微,目前未对下游江下泉群产生异常影响。

Source of Gushing Water in Karst Tunnel and Its Influence on Groundwater Environment

Taking a typical karst water gushing tunnel in PingLe geotectogene as the research object,the main source of tunnel gushing water was found through regional hydrogeological survey and geophysical exploration;tracer test and dynamic monitoring were used to study the influence of tunnel gushing water on surrounding groundwater environment.The results show that the east-west karst strong runoff zone developed along the contact zone of the Xiaojiangbian formation and Maokou formation on the syncline axis and receiving surface water replenishment from the karst trough on the west side is the main source of water gushing at the tunnel bottom of DK1764+490—DK1764+510 section.After the construction of the tunnel,some channels and flow directions of the Jizusi underground river have changed,but it can still receive precipitation replenishment through the karst geotectogene on the east side of the tunnel,so part of the flow can be restored in the rainy season.The grouting at the bottom of the tunnel has a good effect on blocking the water gushing channel,and at the same time has a slight impact on the karst water strong runoff zone at the syncline axis.At present,it has not had an abnormal impact on the Jiangxia springs.