边坡虹吸排水数值模拟方法及应用

边坡虹吸排水是处于探索应用阶段的新技术。基于广义达西定律与渗流场分析的基本原理，将“以管代孔”法与解析单元法相结合，提出针对虹吸排水系统的数值模拟方法。按照流量和水头等价的原则，给排水孔赋予等效的渗透系数，并根据虹吸排水原理确定其内水头边界条件，以此模拟虹吸排水过程。建立边坡三维渗流有限元计算模型，以单个排水孔为例，计算虹吸排水作用前、后坡体内地下水位线与渗流场分布的变化，揭示了虹吸排水对边坡地下水渗流场的影响规律。在排水孔径和孔长恒定的条件下，模拟了排水孔位置变化对排水效果的影响，结果表明边坡虹吸孔位选择对排水效果有重要影响。

NUMERICAL SIMULATION METHOD FOR SIPHONIC DRAINAGE IN SLOPE AND ITS APPLICATION

The siphonic drainage in slope is a type of new technology in the stage of explorative application. Based on generalized Darcy?s law and the basic principle of seepage，combining the“pipe to represent hole”method and analytical element method，a numerical simulation method for siphonic drainage system is proposed. In order to simulate the process of siphonic drainage，we give the drainage hole a equivalent permeability coefficient according to the equivalence principle of flow and head. And the hydraulic boundary conditions according to the principle of the siphonic drainage are determined. As an example，a three-dimensional finite element seepage model with a single drainage hole is established. The groundwater line and the change of seepage field distribution in the slope before and after siphonic drainage are calculated，which reveal the influence law of siphonic drainage on the groundwater seepage field. In conditions of constant of drainage hole diameter and length，effects of the change of position of drainage hole on drainage have been simulated. The results indicate that the selection of siphonic hole position in slope has important influence on drainage.