考虑分界面的黏性泥石流下游演进数学模型研究

基于分界面理论,以泥石流屈服深度对应的面为分界面,将黏性泥石流分为理想流体和Bingham流体,建立了模拟黏性泥石流演进过程的数学模型和相应计算方法。该模型基于泥石流的运动特征,注重不同层间泥石流流速的差异,并可合理反映泥石流运动速度对其演进形态的影响机制;同时,全面考虑了黏性泥石流在演进过程中所呈现的"舌状体"和"龙头"由上向下翻落现象,因此可更准确描述黏性泥石流在演进过程中的运动状态。采用3组模型试验结果对建立的数学模型与计算方法进行了验证,结果表明:模型计算得出的泥石流泛滥范围和最大堆积厚度与模型试验结果误差在±5%以内,验证了模型的合理性。

Numerical simulation of evolution of viscous debris flows considering interface

Based on the interface theory, taking the corresponding surface of the yielding depth of debris flows as the interface, the viscous debris flow can be divided into ideal fluid and Bingham fluid. Thus, a numerical model and the relative algorithm are developed to simulate the evolution of debris flows. The model is based on the motion feature of the debris and cosiders the velocity differences of debris flows in different layers, thereby, it can reasonably describe the evolution mechanism and the influences on the morphology of debris flows due to the flow velocity. Meanwhile, the model fully considers the phenomena of “tongue-like” and “debris flow head” of actual debris flows, thus, the motion state of the debris flows during the evolution can be depicted accurately. A series of model tests are adopted to verify the proposed numerical model and the algorithm. The comparison between the measured and calculated results indicates that the relative errors of the inundation areas and the maximum accumulation thicknesses are within ±5%, and the rationality of the proposed model is validated.