Study On Optimization Of Ventilation Scheme For Extra Long Road Adjacent Tunnel Based On The Influence Of Pollutant Crossflow

In recent years,with the rapid development of social economy and the improvement of highway network in China,freeway has begun to expand to plateau and mountainous areas,highway tunnels are increasingly appearing in highway construction.With the emergence of new technology,the construction level of freeway is constantly improving,and the tunnel alignment is greatly optimized,which makes the scale of freeway tunnels in mountainous areas grow rapidly,and the operation ventilation problem of adjacent tunnels is highlighted.The distance between the upper and lower entrances of adjacent tunnels is close,the flow of pollutants between the openings will have adverse effects on the operation ventilation of downstream tunnels.Therefore,it is of great practical significance to study the flow law of pollutants in the operation ventilation of adjacent tunnels and to put forward reasonable ventilation scheme and operation control scheme.In this paper,the characteristics of contaminant channeling in adjacent tunnels are studied by means of data investigation,theoretical analysis and numerical simulation.The optimization of ventilation scheme and operation control scheme are designed based on the characteristics of channeling.The main contents of this paper include:(1)A discrete phase method is proposed to simulate dust crossflow in adjacent tunnels.(2)The numerical simulation software Fluent is used to study the crossflow of CO in adjacent tunnels under the influence of wind speed combination,temperature difference inside and outside tunnels,and canyon wind,and the crossflow characteristics are obtained.(3)DPM(discrete phase)model is used to study the dust crossflow in adjacent tunnels.The characteristics of dust crossflow in adjacent tunnels are obtained by simulating the combination of wind speed in upper and lower tunnels,the temperature difference between inside and outside tunnels,and the influence of canyon wind.(4)Based on the cross-flow characteristics of contaminants in adjacent tunnels,a modified air demand calculation method considering the crossflow of contaminants is proposed,and the optimum ventilation scheme of Yemajian 1 tunnels with vertical air supply and exhaust and right tunnel air supply is determined.Finally,two operating ventilation control conditions are formulated for different Canyon wind speeds.