酒泉至额济纳铁路防沙堤风洞试验数值模拟及积沙试验研究

防沙堤是造价低、使用广泛的工程防沙措施。对三角形和梯形截面防沙堤进行系统对比研究,总结出两种防沙堤的优缺点。通过风洞试验对不同断面形状的防沙堤的流场结构、流场压力分布、积沙情况进行对比研究,然后利用FLUENT数值模拟方法对风洞试验进行验证对比。研究结果和结论:(1)梯形横断面防沙堤迎风侧形成的低速区域宽度大于三角形,梯形迎风侧对沙粒的沉积、滞留作用优于三角形;(2)三角形横断面防沙堤背风侧产生的有效防护宽度大于梯形,防护效果优于梯形;(3)风沙流遇防沙堤阻挡在迎风侧坡脚受阻堆积,积沙达到堤体2/3高度时不再继续堆积增高,一部分向两侧随风流导向两端处,另一部分沿坡越过堤体顶部在落沙坡堆积。准备建设的风沙铁路酒额线及其他交通、民用建筑可以利用以上成果选择防沙堤的形状以达到最好防沙效益。

Study on Sand Dike through Wind Tunnel Numerical Simulation Test and Sand Pile Test on Jiuquan to EJiNa Railway

Sand dike is a low cost and widely used sand-control engineering method. The paper studies systematically the triangular and trapezoidal cross-section sand dikes and sums up the advantages and disadvantages of the two. The flow field of the structure, the pressure of the flow field and the accumulation of sand of sand dikes with different cross section are compared and studied by means of wind tunnel test. Then the wind tunnel test is verified and compared by using FLUENT software numerical simulation. The results of the study show that:(1) the width of the low speed area formed in front of the trapezoidal sand dike is bigger than that of the triangle one; considering the groin area in front of the grains of sand deposition and retention, the trapezoidal is more effective than the triangle;(2)considering the effective sand-control behind sand dike,the width of the groin of the triangle is greater than that of the trapezoidal and the effect of the triangle is better than that of the trapezoid;(3) the sand piles up in front of the sand dike and stops piling when it reaches two-thirds of sand dike height,part of sand is blown to the two ends of the sand dike and another part is blown over the top of the sand dike and falls on the sand accumulation slope. The proposed Jiuquan to EJiNa Railway and other modes of transportation and civil architectures can make use of the above results to decide their individual shape of sand dike for best sand-control.