摘要
通过长斜井进入正洞施工的特长隧道,往往面临独头通风距离过长、工作面风量不足等问题,造成污染物难以在规定时间排出洞外。以衢宁铁路鹫峰山隧道风仓接力施工通风为依托,采用数值模拟方法研究了风仓长度、隔板长度及风机布置方式对轴流风机通风效率的影响,分析了原压入式通风和风仓接力通风洞内CO运移特性。结果表明,风仓长度从10 m增至25 m时,轴流风机通风效率大幅提高,风仓长度大于25 m时,对轴流风机通风效率的影响不大。设置中隔板会影响空气在风仓内的分流并产生较多旋流,从而降低风机通风效率;轴流风机远离斜井端对称布置,风仓内部风流的引流速度和引流范围最大,风流运动路径最优,通风效率最高。由于压入式通风受限于斜井断面尺寸及现场布置方式,当通风距离超过3 000 m后,无法满足洞内作业环境规定的条件。在正洞与斜井交叉部位设置密封的风仓,形成接力通风,能大幅度延长通风距离,提高通风效率,改善洞内空气质量。
Relying on the relay construction ventilation example based on the air cabin of Jiufengshan tunnel in Quzhou-Nanjing Railway,the paper has done a numerical simulation to pursue the effect of the air cabin length,the partition length,and the ventilation effect and efficiency of the axial fan arrangement.As a matter of fact,it has long been a problem in the construction of the extra-long tunnels due to the long distance ventilation and insufficient air volume supply in the working face,which may cause serious pollution and the exhaust gas discharge for the special space and time.Therefore,we have done a careful analysis of the particular status-in-situ of the CO migration in the originally forced ventilation and air cabin ventilation.The results of our investigation show that,when the air cabin length increases from 10 m to 25 m,the ventilation efficiency of the axial fan has to be greatly recreated and heightened.For example,when the ventilation length is over 25 m,there may exist somewhat effect on the ventilation efficiency of the axially flowing fans.However,when the partition affects the air flow in the air cabin and generate more swirling flow,it may tend to reduce the ventilation efficiency of the fan.But,in contrast,when the axial fans are arranged symmetrically away from the inclined shaft,its velocity and drainage range of the airflow in the air cabin can reach its maximal limits.In addition,its air flow path can be optimalized with its ventilation efficiency being made to its maximal limits.Besides,since the forced ventilation of the fan is limited to the section size of the inclined shaft and the site layout method,it remains unable to meet the expected or required operating conditions in the tunnel in case the ventilation coverage is beyond 4 000 m.In such a situation,a sealed air cabin can be created at the intersection of the main hole with the inclined shaft to form a relay ventilation,so as to extend the ventilation distance to a considerable extent and enhance the ventilation efficiency as well as to improve the provision of the fresh air in the tunnel.Thus,it can be said that the research finding of the paper has created and opened up a new approach to the construction ventilation of the extremely long tunnels.
作者
张恒
张俊儒
周水强
孙建春
吴洁
ZHANG Heng;ZHANG Jun-ru;ZHOU Shui-qiang;SUN Jian-chun;WU Jie(The 1st Bureau Co.,Ltd.,China Kailway Tuninel Group,Chongqing 410000,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2019年第3期795-803,共9页
Journal of Safety and Environment
基金
国家自然科学基金项目(51508477)
教育部创新团队发展计划项目(IRT0955)
中央高校基本科研业务费专项(SWJTU11ZT33)
关键词
安全卫生工程技术
施工通风
长大斜井
风仓设置
数值模拟
safety and health engineering technology
construction ventilation
long inclined shaft
air cabin setting
numerical simulation
