特长隧道压入式通风结合射流风机通风方案优化

Optimization of ventilation scheme based on combination of press-in ventilation and jet fan in extra long tunnel

为了降低隧道施工时产生的粉尘对施工人员身体健康的危害以及对施工机械的磨损,以新建中兰(中卫—兰州)铁路香山隧道DK052+415~DK054+500施工段为依托工程,对施工期间斜井段通风方案进行了优化。利用Fluent仿真模拟分析了施工段射流风机距隧道中线距离、射流风机风速、射流风机距挂布台车距离、射流风机高度对隧道除尘效果的影响,采用正交试验法研究了风机距挂布台车距离、风机距隧道中线距离及风机风速对除尘效果的影响程度,并对射流风机的布置方案进行了比选优化。结果表明:隧道中两台车处会出现粉尘浓度升高的现象,隧道中安装射流风机辅助通风可以降低两台车附近粉尘浓度;风管和射流风机布置在同侧时,风机的除尘能力会由于两者之间的摩擦而降低;风机风速对射流风机的除尘能力具有积极影响;风机距台车距离和风机高度均存在最优值,过大或者过小都会降低射流风机的除尘效果;射流风机最佳布置方案为风机距挂布台车35m,风机距隧道中线2m,风机高度2m,风机风速40m/s;极差分析法和方差分析法均表明射流风机除尘效果的最大影响因素为风机风速,各因素对两台车附近粉尘浓度影响的重要性顺序由大到小为风机风速、风机距挂布台车距离、风机距隧道中线距离。在隧道施工时,斜井段通风工程中需要重点关注风机风速对射流风机除尘效果的影响。

In order to reduce the harm of dust generated during tunnel construction to the health of construction workers and the wear of construction machinery,based on the construction section DK052+415~DK054+500of Xiangshan Tunnel of Zhonglan(Zhongwei-Lanzhou)Railway,the ventilation scheme of inclined shaft section during construction was optimized.The influence of the distance between the jet fan and the center line of the tunnel,the wind speed of the jet fan,the distance between the jet fan and the cloth hanging trolley,and the height of the jet fan on the dust removal effect of the tunnel were analyzed by using Fluent simulation.The influence of the distance between the fan and the cloth hanging trolley,the distance between the fan and the tunnel center line,and the fan wind speed on the dust removal effect was studied by using the orthogonal test method,and the layout scheme of the jet fan was compared and optimized.The results show that the dust concentration increases at the two vehicles in tunnel.The installation of jet fan auxiliary ventilation in the tunnel can reduce the dust concentration near the two vehicles.When the air duct and jet fan are arranged on the same side,the dust removal capacity of the fan will be reduced due to the friction between them.The wind speed of the fan has a positive impact on the dust removal capacity of the jet fan.The distance between the fan and the trolley and the height of the fan have optimal values,too large or too small will reduce the dust removal effect of the jet fan.The best layout scheme of jet fan is that the distance between the fan and the cloth trolley is 35m,the distance between the fan and the tunnel center line is 2m,the fan height is 2m,and the fan wind speed is 40m/s.Both range analysis method and variance analysis method show that the biggest influence factor of jet fan dust removal effect is fan speed.The order of influence importance of each factor on the dust concentration near the two vehicles is fan speed,fan distance from the cloth trolley and fan distance from the tunnel center line.During tunnel construction,the impact of fan speed on the dust removal effect of jet fan needs to be focused in the ventilation project of inclined shaft section.7tabs,16figs,33refs.