泥石流拦砂坝排泄孔优化及其数值模拟研究

摘要

In order to improve the ability of drainage hole, an optimal strategy for drainage hole aimed to adjust outflow volume was proposed.Preliminary research including the influence of cross-section and transverse-section types to the drainage ability of drainage hole as well as the applicability to different type of fluid were carried out by numerical simulation.80 modeling experiments were did under the orthogonal combination of 5 cross-section types, 4 longitudinal-section types and 4 fluid density conditions.Define average discharge volume-Q and descent rate of flow depth in front of dam as evaluating indexes, the results showed that rectangular cross-section with proper width to length ratio promised a better effect than other types for all kind of fluid conditions, that is, smaller width to length ratio suit for lower density fluid and square cross-section for higher density fluid.The average descent rate of flow depth increased with the increase of longitudinal slope gradient of drainage hole as well as the enlarged cross-section area along the longitudinal direction.The higher fluid density was the lower discharge ability of the drainage hole displayed.%为改善拦砂坝排水孔堵塞问题，提出了以调节泥石流流量为主的排水孔优化策略；并通过数值模拟初步研究了横、纵断面形态对优化后的排水孔（排泄孔）排泄能力的影响，以及排泄孔对不同性质的泥石流的排泄效果。通过对横断面形态、纵断面形态及浆体容重三因子的正交组合，进行了80组模拟试验，以平均排泄流量-Q和坝前泥深下降速率为主要评价指标，结果表明具有合理宽深比的矩形横断面相对最优。对容重较小的流体，窄深型的矩形断面排泄能力最好；而对高容重流体，则正方形断面相对更好。在可流动范围内，排泄效果随着排泄孔纵比降的增大而增大；而增大沿程排泄孔横断面截面积（变截面一坡到底喇叭型）可提高相同纵比降排泄孔的排泄能力。同时，随着流体容重的增加，排泄孔的排泄能力逐渐降低。