隧道施工通风系统中竖井风量及影响因素分析

解决特长或单斜井多作业面隧道的施工通风问题常常需要增设通风竖井。为深入分析影响竖井通风的因素，以竖直圆管代替竖井，假设其内壁温度沿井壁线性变化，首先，推导出含内热源的竖井截面内稳态气流的平均风速表达式；然后，采用泰勒级数法得到竖井通风量的表达式。研究结果表明： 1）在隧道入口处大气压Pa5与进风竖井井口大气压Pa1的变化保持一致的情况下，两者差值不会对隧道施工通风产生影响。2）当Pa5与Pa1变化不同步时，两者差值（Pa5-Pa1）增大使得竖井进风量减小。3）位于进风竖井井底的风机所需风压随井口大气温度的升高而减小，随地层温度升高而增大。4）在环境参数与工作条件确定的情况下，可应用竖井风量表达式实现需风量定量分析。

Determination of Ventilation Volume for Special Ventilation Shafts of Tunnel Construction and Its Influencing Factors

Ventilation shafts are often required to solve the construction ventilation problems in extra long tunnels or multiple working faces in tunnels with a single slope. To investigate the factors affecting the ventilation of the shafts, the vertical tube is used to replace the shaft, it is assumed that the temperature of the wall changes linearly along the shaft, and the expression of the average wind speed of the steady state airflow in the shaft section with heat source is derived subsequently. Then, the expression of demanded ventilation volume for shafts is obtained using Taylor series. The results reveal the following: (1) When the atmospheric pressure 〖WT５《TNR#I》〗P〖WT５《TNR》〗a5 at the tunnel entrance is consistent with the change of the atmospheric pressure 〖WT５《TNR#I》〗P〖WT５《TNR》〗a1 at the shaft orifice, the difference between the two will not affect the construction ventilation of tunnel. (2) When the changes of 〖WT５《TNR#I》〗P〖WT５《TNR》〗a5 and 〖WT５《TNR#I》〗P〖WT５《TNR》〗a1 are not synchronous, the increase of the difference (〖WT５《TNR#I》〗P〖WT５《TNR》〗a5-〖WT５《TNR#I》〗P〖WT５《TNR》〗a1) will result in the decrease of the inlet air volume of the shaft. (3) The wind pressure required by the fan located at the bottom of the shaft decreases with an increase in atmospheric temperature at the orifice, and increases with an increase in the stratigraphic temperature. (4) When the environmental parameters and working conditions are specified, the shaft ventilation rate expression can be used for quantitative analysis, which is conducive to fan selection and intelligent control of fan operation.