三洞并行公路隧道施工期通风方案设计与优化OA

Taking the Daliangshan No.1 Tunnel of the Leshan-Xichang Expressway as the research object,this study proposes improved measures of adding air doors and jet fans to optimize the ventilation effect for the local polluted air recirculation problem existing of the original ventilation scheme.Subsequently,numerical simulation methods are adopted to analyze the ventilation characteristics of the improved scheme.The reliability of the simulation results is verified by combining with on-site monitoring data.The analysis results show that the addition of air doors can effec-tively block the local polluted air recirculation path;The axial flow fans reduce the air kinetic energy loss by effi-cient air exhaust,significantly increase the wind speed at the air outlet,and optimize the overall ventilation effi-ciency in the tunnel.After the flow field reaching a stable state,the maximum gas concentration is focused near the tunnel working face,while the peak concentration of CO appears in the parallel pilot exit area with the trend of"first decreasing and then increasing";The gas concentration in the eddy current area rises faster,the gas concentration gradient in the recirculation area increases significantly,and the maximum gas concentration may fluctuate under the influence of changes in ventilation condition parameters;From the opposite side to the same side of the air duct,the gas concentration in the stable recirculation area shows a gradually increasing distribution characteristic.The on-site monitoring results indicate that all the migration law,concentration distribution characteristics of pollutants(gas and CO)and the actual distribution of the wind speed field in the tunnel are highly consistent with the flow field characteristics obtained by numerical simulation,which further verifies the rationality of the improved scheme and the numerical simulation method.