高海拔公路隧道施工期粉尘运移特性研究

为了确定不同海拔高度地区公路隧道施工期粉尘运动规律和粉尘质量浓度分布特性,依托巴朗山高海拔隧道工程展开研究。依据气固两相流理论,利用流体计算软件FLUENT,采用三维k-ε湍流非稳态离散相模型,对公路隧道施工期间粉尘质量浓度在隧道内分布特性及其浓度随海拔高度变化规律进行了三维数值模拟计算分析。研究结果表明:考虑湿度与不考虑湿度对不同海拔地区空气密度计算结果影响误差在0.3 %左右;粉尘在隧道内向洞口运动的动态过程中,最高浓度逐渐降低,在隧道内呈U型形态分布趋势,靠近隧道底部的粉尘浓度高于隧道顶部粉尘浓度;随着海拔高度增加,同一测点粉尘质量浓度随海拔高度以线性形式减小,粉尘浓度海拔高度修正系数可按K=-3×10^-5 h+1进行计算。

Migration Characteristics of Dust during Construction Stage inHighway Tunnels at High Altitude Areas

The movement regularity and mass concentration distribution characteristics of dust during the construction stage of highway tunnels at different altitudes are studied based upon the Balangshan tunnel. The distribution characteristics in highway tunnel and the regularity variation at different altitudes of dust concentration are simulated and analyzed with FLUENT through the three-dimensional k-ε unsteady turbulent DPM model. The measured data agrees well with the numerical simulation results. The results indicate that the influence of air humidity at different altitudes on the deviation of air density calculation results is about 0.3%. The peak concentration of dust decreases gradually in the dynamic processes of movement to the tunnel entrance, which is U-shaped distribution in the tunnel. Dust mass concentration at the bottom of the tunnel is higher than that at the top. For the impact of environmental atmospheric pressure with the altitude increase, the mass concentration of dust decreases linearly at the same measuring point, the correction coefficient can be calculated by K=-3×10^-5 h+1.