辽宁省东部山区沿河公路微弯段水流冲刷的数值模拟  

Numerical Simulation on Current Scour of Microbend Subgrade River Side of Eastern Mountainous Area of Liaoning Province

作　　者：张敏江[1] 孙长辉[1] 

机构地区：[1]沈阳建筑大学土木工程学院,辽宁沈阳110168

出　　处：《沈阳建筑大学学报（自然科学版）》2013年第2期237-242,共6页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金项目(40673045);辽宁省交通厅科研项目(201112)

摘　　要：目的研究辽宁省东部山区沿河公路顺直微弯段路基的冲刷机理,为制定合理的防护措施提供理论依据,以提高路基的抗水毁能力.方法选取弯道中心角为20°的弯道,采用数值模拟手段,通过系统的计算机仿真模拟,分析三维弯道流场中典型防护构造物的工程力学行为.结果弯道上游断面处的流速分布较为均匀,出口处流速分布不均匀,凹岸侧的流速大,凸岸侧流速偏小,弯道凸岸侧存在回流区.弯道入口处动压力值较小,分布较为均匀,随着流场的发展,在弯道下游出口处的凹岸达到最大值.弯道凹岸与凸岸均存在高剪切应力区,位于凹岸附近剪切力小于凸岸.加设顺坝群后,弯道凹岸附近的力学参数值均有一定程度的减小.结论弯道凹岸的切应力区将直接影响沿河公路路基的稳定性,致使其坡脚被冲刷淘空,需采取有效措施(如挡墙、顺坝、丁坝)加以防护.数值模拟结果与现场实地调查结果一致,说明顺坝可以保护回流区长度范围内的河岸路基.The paper is written to understand the roadbed scour mechanism of microbend subgrade river side of eastern mountainous area of Liaoning province, provide theoretical basis for formulating reasonable protective measures and improve the subgrade resistance ability of flood. Select curve of comer angle at centre for 20.,use the numerical simulation method,analyze the engineering mechanics behavior of typical protection construction in three dimensional flow field by computer simulation. The results turn out that flow velocity spread uniformly in Section place of upstream, flow velocity spread unequally at the exit, the flow rate of concave shore side is greater than the flow velocity of convex bank side, backflow zone exist in convex bank side. Dynamic pressure value is smaller at the entrance of curve, spread uniformly, with the development of the flow field, the dynamic pressure of concave bank is the largest at the exit of curve downstream. The shear stress is very high round concave bank and convex bank,the shear stress round convex bank is higher than the shear stress round concave bank. After adding the dam group,mechanics parameter value reduced to a certain extent near cut bank of comer In conclusion the shear stress round concave bank will influence the roadbed stability along the river directly ,the side slope of thesubgrade is scoured,and then it is hollowed out,we need to take effective measures to defend,such as retaining wall ,longitudinal dike,spur dike. The result of numerical simulation and the result of field survey is consistent, which shows that the dam can protect recirculation region within the scope of the river embankment.

关 键 词：微弯段 冲刷机理 数值模拟 动压力 剪切力 

分 类 号：U442.32[建筑科学—桥梁与隧道工程]