基于渗流和管流耦合的管涌数值模拟

Numerical simulation of piping based on coupling seepage and pipe flow

堤坝地基的渗透变形过程实际上是"土中水"转变为"水中土"的过程。在渗透变形发生的集中管涌通道区域,采用常规渗流分析理论,单纯增大管涌通道渗透系数的方法是不太合适的。在未发生渗透变形的区域,用常规渗流理论计算;在管涌通道区域,用管流理论,公共边界上两者之间水头相等、流量大小相等且方向相反,能够较好符合渗透变形的发展规律。为了适应计算过程中内部边界条件不断变化的特点,采用无网格法伽辽金法(elementfreeGalerkinmethod,EFG)对渗流场进行计算。算例计算表明,这种渗流-管流耦合的方法能够模拟管涌通道绕过防渗墙等复杂的发展过程。

The course of seepage deformation in embankment foundation is actually the course of＂water in soil＂ turning into ＂soil in water＂. It is not very appropriate for conventional seepage theory to conduct the analysis with just increasing the permeability coefficient of the piping channel. A more suitable method proposed here is using the pipe flow theory in the piping channel; and conventional seepage theory in the rest. On their common boundary of the two computational domains they share the same water head and equal value of discharge rate with opposite sign. Element free Galerkin method （EFG） is employed to facilitate the computational changeable boundary between the two domains. Example shows this coupling of seepage and pipe flow can simulate the complex process such as the piping channel bypassing the cutoffwall and advancing upstream.