引汉济渭隧洞TBM施工环境热害扩散规律研究

Study on the thermal hazard of the TBM construction environment in tunnel of the Hanjiang-to-Weihe River Water Transfer Project

引汉济渭工程是解决关中、陕北缺水的重要工程,其将穿越秦岭主脊段,主要采用TBM法施工。理清TBM掘进段的施工环境热害扩散规律,用以指导TBM掘进隧道内的现场施工。以引汉济渭隧洞工程为依托,主要采用数值计算方法对不同围岩级别和不同通风条件下TBM掘进段的施工环境热害扩散规律进行计算研究。研究结果表明:在Ⅳ级围岩中施工时,掘进机段环境空气温度小于28℃,满足规范要求。随着围岩级别提高,掘进面附近区域温度和高温区范围逐渐扩大,最高温度达到50℃,最大热害扩散范围达到165m,最小的通风有效降温距离仅为45m;随着风管出风口风速的增大和送风温度的降低,热害扩散范围逐渐减小,但仍难以使掘进面附近环境温度满足规范要求,建议在掘进面附近区域采用局部降温措施。

The Hanjiang-to-Weihe river water transfer project is an important project to solve water shortage in the central Shaanxi plain and northern Shaanxi.It will pass through the main ridge section of the Qinling Mountains and is mainly constructed by the TBM method.This paper intends to clarify the diffusion rule of thermal hazard in the construction environment of the TBM tunneling section to guide the construction of the TBM tunnel.This paper is based on the tunneling project of the Hanjiang-to-Weihe river water transfer project.Numerical calculation was used to calculate the thermal hazard diffusion rule in the construction environment of TBM tunneling sections under different surrounding rock grades and different ventilation conditions.Results showed that in the construction of class IV surrounding rock,the ambient air temperature of the TBM section was less than 28℃,which met the specification requirements.With the improvement of the surrounding rock grade,the temperature near the driving surface and the scope of high-temperature area would gradually increase.The maximum temperature reached 50℃and the maximum diffusion range of thermal hazard reached 165 m.The minimum effective ventilation cooling distance was only 45 m.With the increase of wind speed at the outlet of the air duct and the decrease of the supply air temperature,the diffusion range of thermal hazard would gradually decrease;but the ambient temperature near the driving surface still could not meet the specification requirements.Therefore,this paper recommends using local cooling measures in the vicinity of the driving surface.