兰新第二双线铁路防风明洞实验段风荷载数值模拟研究

介绍了高速铁路防风明洞的基本作用及设计方法;利用计算流体动力学原理中的数学模型及控制方程,对兰新第二双线铁路防风明洞大风作用下的风荷载进行了分析;通过计算工况的假定以及边界条件的合理设定,采用有限体积法建立防风明洞数值分析模型,并模拟计算了平地路段、浅路堑地段和路堤地段三大类工况和70、60、50、40m/s4种风速情况。研究结果表明：①开孔情况下,明洞各部位所受风荷载随着风速增大而增大;②明洞迎风侧均为正压,平地地段与路堤地段所受正压较接近,最大值出现在风速为70m/s时,迎风边墙正压为3202Pa;③明洞拱顶及背风侧均为负压,浅路堑地段所受负压最大值出现在风速为70m/s时,拱顶负压为-3550Pa;④各地段背风侧所受负压均小于-1500Pa,背风墙脚与背风边墙受力基本相同;⑤各地段各风速情况下,拱顶处负压均为最大;⑥开孔情况下的明洞各部位风荷载,普遍小于不开孔情况;⑦明洞开孔附近有回流风速,并随着外界风速增大而增大。

Numerical Simulation of Wind Load in Experimental Section of Lanzhou-Xinjiang High-speed Railway Anti-wind Tunnel

In this paper, the basic functions and design methods of Lanzhou-Xinjiang high-speed railway anti-wind tunnel were introduced. Based on computational fluid dynamics principles, the basic mathematic model and the control equation of the wind load in strong wind condition of the tunnel was analyzed. According to the assumed calculating conditions and reasonable setting of boundaries, anti-wind tunnel numerical analysis model was established by finite volume method. Besides, three types of condition which are flat section, the shallow cuts lot and embankment lot under the wind speed of 70 m/s, 60 m/s, 50 m/s, 40 m/s respectively were simulated and calcu- lated. Results show. （1）the wind load on various parts of anti-wind tunnel with holes rises with the increase of the wind speed; （2） the wind pressures on all the windward sides are positive, the positive pressures on the flat sections are similar to that on embankment lots, and are 3202 Pa under a maximum wind speed of 70 m/s; （3） the wind pressure on vault and leeward sides are negative and the shallow cuts lot suffers the largest negative pressure, in which the vault bears -3550 Pa under a maximum wind speed of 70 m/s; （4） the negative pressure on the leeward sides of all conditions are less than -1500 Pa while the leeward wall foot and the leeward side wall suffer similar pressure~ （5） under all circumstances, the negative pressure on the vault is the highest; （6）the wind load on various parts of anti-wind tunnel with holes is generally smaller than that on tunnels without holes; （7） there are reflux wind speed near the holes of anti-wind tunnel, which rises with the increase of outside wind speed.