考虑土体坍塌的单层堤基管涌数值模拟方法研究

为了更真实地模拟土体管涌发展过程，需要考虑管涌区以上土体可能发生的坍塌。根据土拱理论和土体坍塌机理，提出了单层堤基管涌区上覆土体稳定性和坍塌的判别方法，完善了堤基管涌扩展数值模拟方法和程序。通过对有悬挂式防渗墙的单层非黏性土堤基管涌扩展过程的模拟，揭示了考虑上覆土体稳定性和坍塌作用时的管涌扩展规律。结果表明：管涌扩展初期，土体没有产生坍塌；当管涌扩展接近悬挂式防渗墙时，管涌区上覆土体开始出现坍塌；当管涌绕过防渗墙向上游扩展后，管涌区上覆土体的坍塌对管涌扩展路径影响较大。这说明，管涌发展到一定阶段后，土体实际发生破坏的区域比不考虑坍塌作用时模拟得到的破坏区域更大。

Numerical Simulation of Piping in the Dyke of Uniform Foundation Considering Soil Collapse

To more authentically simulate the process of soil piping,the probable collapse of soil above piping zone should be taken into account.On the basis of soil arch theory and soil collapse mechanism,methods for judging the stability and the collapse of soil above the piping zone in the dyke of uniform foundation were presented.The numerical simulation method and calculation program were improved.By simulating the process of piping in the dyke of uniform foundation of non-cohesive soil and suspension-type cut-off wall,the rules of piping development in the presence of soil collapse above the piping zone were revealed.At the early stage,soil collapse does not happen;when the piping approaches to the cut-off wall,soil collapse occurs;when the piping bypasses the cut-off wall and develops toward the upstream,soil collapse has great influence on the path of piping.It is shown that the real failure zone would be larger than that in the numerical simulated results regardless of soil collapse.