板桥河左岸堤防渗透破坏风险分析

以板桥河左岸堤防加固工程为背景，提出了一条基于确定性渗流有限元进行堤防渗透破坏风险分析的途径，并对板桥河堤防渗透破坏风险进行了分析研究，根据分析结果对堤防渗透稳定性进行了评价。所采用研究方法发挥了有限元的优点，能够模拟堤防场地土层实际分布情况，较准确地计算洪水位下运行堤防背水面水力坡降。根据“端点组合-单调性法”理论和“3?”法则，通过1995年堤防典型破圩实例建立起整个堤防的抗渗临界水力坡降、渗透破坏风险率的临界值以及堤防汛期防渗的警戒水位，对整个板桥河堤防渗透稳定性评价工作具有非常重要的意义，其分析方法以及研究思路可供同类堤防工程的渗透稳定性评价工作借鉴。

Risk analysis for seepage failure in Banqiao River left levee

Based on the case study of Banqiao River left levee, a feasible approach to risk analysis for seepage failure in levees with deterministic seepage FEM was proposed, according to which risk analysis of seepage failure was carried out, and an evaluation of seepage stability was made. The proposed approach could avail itself of the advantage of FEM, and calculate the downstream hydraulic gradient more accurately while considering the soil distribution more actually than those conventional approaches. With the theory of extreme point combination-monotonicity and “3?” Rule, the critical hydraulic gradient, critical risk coefficient of seepage failure and alarm water level for flood prevention in flood season for Banqiao River levee were set up by the failure case in 1995; that are of great significance to seepage stability evaluation. The analytical approach and the results will be practical and helpful in practice of seepage stability evaluation for flood control engineering.