大藤峡工程下游围堰岩溶基础防渗处理设计

Design of seepage prevention treatment of karst foundation in downstream cofferdam of Datengxia project

大藤峡水利枢纽工程,一期下游围堰基础为粘土覆盖层及郁江阶的灰岩和白云岩,其中郁江阶的灰岩和白云岩岩溶发育,且存在岩溶管道与江水连通,基坑开挖极易产生岩溶涌水事故。采用文中设计方案处理,达到了预期目的,基坑总体渗漏量处于可控范围,没有发生较大的基坑涌水事故,该工程岩溶防渗处理方案是成功的。

For the Datengxia hydro-junction project,the foundation of the first stage downstream cofferdam is the clay overburden layer and the limestone and dolomite of Yujiangian Stage.Because of the karst development in the limestone and dolomite of Yujiangian Stage and the connection between the karst pipeline and river,the karst water bursting accidents are easily generated in foundation pit excavation.By adopting the design scheme in this paper,the anticipated purpose is achieved and the total leakage quantity of the foundation pit is in a controllable range,and no serious water bursting accidents occurred.The karst seepage prevention treatment scheme of this project is successful.