安庆城市防洪堤渗流控制

Seepage Control of Flood Embankment by Anqing City

安庆城市防洪堤是长江典型堤段，堤基为强透水深砂层上复盖有复杂的弱透水土层，堤后减压深井百余眼未能达到预期效果并逐年淤堵。文中通过大堤原观资料分析，论证了其现状和减压井逐年淤堵趋势；由室内和现场洗井试验，探求了一种恢复减压井效用的方法。并就７个典型断面进行二维有限单元法渗流计算，比较多种渗控方案效果，针对各堤段特点分别提出堤内压盖、截断复盖土层中夹砂层，维护原减压井列排水线等加固方案。

The flood embankment by city Anqing is a typicalreach of levees along Yangtze River.Its foundation is strong permeability with deeper sand deposits overburden complicated soil layers of weak permeability.Although 100 more relief wells had constructed at landside toe of the embankment but never attained the presupposed effect due to silting year by year.In this paper the present state and tendency of silting gradually in relief wells is verified by analyzing data of field observation.By experiments in laboratory and field a washing method to restore well relieving effect was found.With FEM the 2-D seepage flow computation for 7 typical sections was conducted.After comparison of effects for different seepage control measures the different strengthening schemes such as overburden layer thickened inside,cut-off sand layers,maintainingdrainage line of original relief wells etc. were proposed individually for different reaches of the embankment.