堤防运行工况变化条件下管涌险情整治研究及实践——以汉江遥堤李家洲险段为例

Research and practice on piping treatment under change of embankment operation conditions:case of Lijiazhou section of Yaodi embankment along Hanjiang River

管涌是堤防最常见也是危害最大的险情之一,成因复杂多样,堤防管涌险工段经多次除险加固处理后险情可得到有效控制,但随着堤防运行工况的变化,仍有可能出现新的险情,给治理带来一定难度。为深入研究管涌险情治理措施,以长江流域1级堤防汉江遥堤李家洲险段为例,通过收集该险段历史险情及地质资料,结合已建水利工程现状,详细分析了该险段经除险加固后再次出现管涌险情的原因,并通过三维渗流有限元模型计算揭示了多种工况下该堤段地层渗流场分布特征,提出了水平防渗及排水减压相结合的综合整治措施,选用了新型可拆换式减压井结构,并在库区特殊水文地质条件下付诸实施。该方案已于2022年汛前实施完成,达到预期整治效果。目前汉江中下游已建、在建崔家营、雅口、碾盘山、兴隆等多个梯级,部分堤防的运行工况由汛期短历时挡水转变为长期中高水头运行,研究成果对类似堤防的除险加固及运行维护具有重要的借鉴作用和参考价值。

Piping is one of the most common and harmful dangerous situations in embankments.Its formation is complex and diverse,and the dangerous section of embankment piping can be effectively controlled after many times of danger removal and reinforcement.However,with the change of embankment operation conditions,new dangerous situations may still occur,which brings some difficulties to the treatment.In order to further study the treatment measures of piping danger,taking the first-class embankment in the Changjiang River Basin,Lijiazhou section of Yaodi embankment along Hanjiang River as an example,by collecting the historical dangers and geological data of the dangerous section,combining with the current situation of the built water conservancy projects,the causes of piping dangers in this section after danger removal and reinforcement were analyzed in detail.The distribution characteristics of the seepage field in the embankment section under various working conditions were revealed by the calculation of 3D seepage finite element model.Then the comprehensive treatment measures combining horizontal anti-seepage and drainage decompression were put forward,and a new type of removable relief well structure was selected and implemented under the hydrogeological conditions of the Xinlong Reservoir area.The treatment scheme had been implemented before the flood season in 2022,achieving the expected remediation effect.At present,Cuijiaying,Yakou,Nianpanshan,Xinglong and other cascade reservoirs have been built and under construction in the middle and lower reaches of the Hanjiang River,so the operation conditions of some embankments have changed from short-term water retaining in flood season to long-term medium and high head operation.The research results can provide references for the reinforcement and operation-maintenance of similar embankment projects under influences of reservoirs operation.