活塞风作用下双竖井隧道内微波折射率结构常数的估算模型

Microwave Refractive Structural Constant Modeling in Double-shaft Tunnel under Piston Wind Action

基于Monin-Obukhov相似性原理和Bulk方法,采用Frederickson公式,结合双竖井隧道活塞风的运动特性,建立了不稳定空气环境下双竖井隧道内的大气折射率结构常数估算模型。结合实际项目,对双竖井隧道环境下的微波段的湍流强度进行了仿真计算分析。仿真结果表明:双竖井有良好的通风效果,适当的双竖井间距可有效降低隧道内的活塞作用系数,进而有效降低隧道内湍流强度;竖井间距与活塞风速等因素对于折射率结构常数的作用效果相互关联;与单竖井相比较,双竖井隧道阻塞比对折射率结构常数的影响程度较小。因此,合理设计通风双竖井,有利于隧道内无线电波的传输。

Based on the Monin-Obukhov similarity theory and Bulk method,and in combination with the motion characteristics of double-shaft tunnel piston wind,Frederickson formula is use to establish a model of refractive structure parameter in double-shafts tunnel under unstable atmospheric environment.According to a practical project,the turbulent intensity of the microwave section under the environment of double-shafts tunnel is numerically simulated.The results show that,the double-shaft tunnel has a good ventilation effect,and proper distance between shafts can effectively reduce the piston effect coefficient in the tunnel,leading to the reduction of turbulence intensity in the tunnel;the effects of shaft distance and piston wind speed on the refractive index structure parameters are interrelated;compared with single shaft,the double shaft tunnel has less impact on the refractive structural constant.Therefore,reasonable design of ventilation double-shaft tunnel will facilitate the transmission of radio waves in the tunnel.