一种模拟黏土心墙坝漫顶溃决的水沙耦合数学模型

Coupled Mathematical Model of Overtopping-induced Break of Clay Core Dam

为了减轻黏土心墙坝漫顶溃决的损失,需要对黏土心墙坝的漫顶溃口发展过程进行深入研究。基于黏土心墙坝漫顶溃决机理,建立了黏土心墙坝漫顶溃决水沙耦合数学模型。模型采用的水动力学模型为固液两相湍流方程,考虑了床面变形对于水流运动的影响;使用PLIC-VOF法(分段线性界面重构-流体体积法)使其精确重构自由表面;固壁边界运用基于离散力的浸入边界法,使其更加准确地模拟含有刚体的流体运动;心墙的滑移破坏则通过剪切力进行判断。模型能够在一定程度上反映水流结构、坝面变形和心墙滑移三者之间的关系,经室内水槽试验检验,计算的溃口流量过程与实测值也较为吻合,能够为研究黏土心墙坝漫顶溃口发展过程提供一种可选工具。

The aim of this study is to reduce the losses caused by overtopping-induced dam break.We established a coupled model based on the mechanism of the break process of clay core dam.The hydrodynamic model is a solid-liquid two-phase turbulence equation in consideration of the influence of river bed deformation on water flow.We reconstructed the free surface by adopting PLIC-VOF method,simulated the solid wall boundary using the immersion boundary method based on dispersive force,and judged the slip failure/sliding failure of the core wall by the moment method.We further validated the model by flume experiment,and proved that the model can simulate meticulously and accurately the interaction among the core,the water flow and the bed deformation.The predicted flow rate of the breach is also in good agreement with the measured value.The study can serve as a useful tool for further research on the mechanism of overtopping failure of clay core dams.