Research On Network Analysis And Control Technology For Operation Ventilation Of Complex Underground Interchange

In order to solve the problem of urban traffic congestion and realize the non-interference of vehicles traveling in multiple directions at important intersections of urban roads,underground interchanges are increasingly being planned and built as a supplement of surface roads.Unlike conventional tunnels,the underground interchange tunnel has the characteristics of complex linear shape,three-dimensional intersection,multiple entrances and exits,and multiple points.How to develop a reasonable ventilation control scheme under different natural wind and traffic flow conditions,and realize the ventilation in each tunnel section according to the demand has become an urgent and difficult problem to be solved in the operation of underground interchanges.Based on this,this paper adopts theoretical analysis and numerical calculation to study the airflow flow distribution law and ventilation control technology of underground interchange under multiple ventilation modes and traffic flow conditions,and achieves the following research results:(1)Based on the basic principle of natural ventilation pressure formation,combined with the structural form of underground interchanges,a ventilation network expression method of natural wind pressure between multiple entrances and exits was proposed.Considering the influence of upstream pollutants on downstream airflow,a calculation method of fresh air volume considering upstream pollutant concentration is proposed,which provides a basis for the operation ventilation design of underground interchange.(2)Through the theoretical derivation and ventilation network calculation for two simple underground interchangeable of “?” type and single Y type,the influence mechanism of multiple ventilation forces on the solutionn equation is explored,and the influence law of ventilation dynamics changes at different locations on the stability of the wind network is obtained.(3)Based on the Hengjiang underground interchange,the ventilation network solution program was used to calculate the distribution of airflow in each tunnel section under different natural wind and traffic flow conditions,and the influence of multiple ventilation forces on the stability of the wind network was investigated;By comparing various ventilation control schemes,the influence of different fan opening positions and numbers on the air volume of each tunnel section was explored,and the optimal ventilation control scheme was obtained.(4)Based on the Huimin underground interchange,the ventilation network solution program was used to calculate the airflow distribution of each tunnel section under various vertical shaft segmental longitudinal ventilation modes,to clarify the influence of vertical shaft air supply and exhaust on the air volume of each tunnel section in the interchange,and to obtain the optimal ventilation control scheme.