高速铁路隧道有毒物质环境下修建技术研究

杭黄铁路天目山隧道施工时遇到有毒物质,为避免施工人员受到伤害,有效推进工程建设,开展现场监测分析,发现放射性 核素²³⁸U比活度平均值为236.3 Bq/kg,高于全国平均值39.5 Bq/kg,隧道空气中钒最高质量浓度达到77.88 μg/m3,为职业接触限 值的1.6倍,爆破后产生的SO2、CO有害气体是限值的几十倍。 通过理论计算和现场试验,采取超前周边预注浆、结构衬砌加强、加 强通风、喷雾降尘等针对性措施,有效屏蔽了辐射影响,贯通后施工人员总照射年有效剂量为0.386 mSv,低于目标管理限值1 mSv。 有害气体、粉尘和钒的质量浓度均低于检出限值。 结果表明: 采用的技术措施对处理有毒气体及辐射有着显著效果,确保了施工 人员安全和施工进度,保证了铁路运营安全。

Construction Technology of High-speed Railway Tunnel under Toxic Substances Environment

The on-site monitoring and analysis results reveal that on the construction site of Tianmushan Tunnel on Hangzhou-Huangshan High-speed Railway, the average specific activity of the radioactive nuclide 238U reaches 236.3 Bq/kg, higher than the state average of 39.5 Bq/kg; the maximum concentration of vanadium in the tunnel reaches 77.88 μg/m3, 1.6 times the occupational limit; and the amount of the toxic gases such as SO2 and CO produced by blasting are dozens of times of the safety limit. The construction of tunnels in hazardous gas and radiation environment is complicated and difficult, which lacks similar engineering experience. As a result, the theoretical calculations and field tests are carried out, targeted measures such as advance pre-grouting, lining structure reinforcement, ventilation strengthening, dust reduction by water curtain, etc. are adopted to effectively avoid the radiation effect. The total effective annual dose of construction workers is 0.386 mSv, which is below the target management limit of 1 mSv. The concentrations of toxic gases, dust and vanadium are also lower than the detection limits. The results show that the adopted technical measures have remarkable effect on the treatment of tunnel construction in toxic gases and radiation environment, which can ensure the safety of construction personnel and construction progress and the safety of railway operations. The results can provide reference for similar projects in the future.