压入式通风模式下高原隧道有害气体分布特征研究
Distribution of harmful gas concentration of plateau tunnel under the forced ventilation mode

针对高原隧道特点,进行风机选型研究,利用现场监测手段得到粉尘和CO的分布特征,结合流体力学原理推导有害气体沿隧道轴向变化规律及工作区处随通风时间的变化规律,建立隧道中有害气体时空分布模型,并对现场测试数据和模型预测进行对比验证。结果表明:有害气体浓度沿隧道轴向呈线性增长分布,掌子面工作区浓度随通风时间呈指数下降变化;不同施工工序CO和粉尘浓度差异较大,应根据不同工序合理选择风机功率,通风距离和通风时间关系着CO和粉尘浓度,可根据理论预测值合理选择不同工序下的风机风量及通风时间。最后建议针对高原隧道施工环境的综合措施。
According to the characteristics of plateau tunnel, the change-law of harmful along the tunnel axis is deduced. The time and space characteristics of harmful gas are then obtained with the time change-law and fluid mechanics principle. The distribution of CO and dust are obtained by using field test method and made comparisons with theoretical analysis. The results show that the harmful gas concentration is linearly distributed along the tunnel axis and the concentration in workplace changed exponentially with ventilation time. The concentration of CO and dust is different obviously in different construction progress, and different ventilation power should be used in different construction progress. The distance and time of ventilation are related to the concentration of CO and dust, and reasonable air volume and time should be selected according to theory value in different construction progress. Finally, comprehensive measures of plateau tunnel construction environment are suggested