Research On Evolution Mechanism And Mitigation Methods Of Aerodynamic Effects Of A High-speed Train Passing Through An Underground Station

The aerodynamic effects induced by high-speed trains passing through underground stations can seriously threat the safety of train operation,the comfort of passengers,and the safety and stability of station facilities and buildings,which is a critical technical problem during the design and operation stage of high-speed railway underground station.Focused on the aerodynamic effect problems of the high-speed railway underground stations,the research method for coupling aerodynamic effects with the complex boundaries of the train-tunnel-station multiparameter,the evolution mechanism of aerodynamic effects in underground stations,along with the mitigation methods for the coupled aerodynamic effects of train-tunnel-station and the structural safety of platform screen doors under aerodynamic loads were systematically studied in this paper.The optimal matching model for alleviation the aerodynamic effects coupling train-tunnel-station is proposed,which can effectively alleviate the aerodynamic effects,improve the fatigue life of platform screen door structure,and ensure the operation safety and stability of underground stations.Main research works in this paper are as follows:The method for the coupling aerodynamic effect with the complex boundaries of the train-tunnel-station multiparameter was established.The numerical simulation and moving model experiment methods for analyzing the aerodynamic effect coupling the train-tunnel-station was established,and the moving model experiment on a structurally complex train-tunnel-station coupling aerodynamic effects was conducted.Additionally,the numerical simulation method was validated using the moving model and full-scale experiment results,and a numerical method suitable for the precise simulation of transient pressure and slipstream in underground stations was determined.The evolutionary mechanism of the aerodynamic effect of high-speed trains passing through an underground station was clarified.The propagation mechanism of the pressure wave in underground station was revealed,and the spatio-temporal evolution law of unsteady aerodynamic effects such as transient pressure and slipstream in underground stations were explored.Besides,the influence laws of train formation length,crossing locations and the platform screen door status on the transient pressure and slipstream was systematically studied,and the distribution laws and evolution characteristics of the slipstream in the platform area with the platform screen door opened were elucidated.The results indicate that the peak values of pressure on the surface of trains and platform screen doors,as well as the peak value of slipstream in the arrival-departure track operation area,increase with the increase of train formation length.Considering the impact of the crossing position on transient pressure and slipstream,it is suggested that trains should cross in the middle of the transition section between station and tunnel.The longitudinal component is the primary component of slipstream in the main track operation area and the arrival-departure track operation area of underground stations;while the transverse component is the primary component of slipstream in the platform waiting area when the platform screen doors are opened.The optimal matching model for mitigating the aerodynamic effects of train-tunnel-station coupling was proposed.The mitigation methods for the aerodynamic effect induced by high-speed trains passing through underground stations were studied,and the influence rules and mitigation mechanisms of key station parameters,such as separating walls,station-tunnel transition sections and ventilation shafts on the aerodynamic effect in underground stations was systematically investigated.The effective methods and control measures to alleviate the aerodynamic effect of underground stations were obtained,and the optimal matching model of key parameters of stations with the optimal aerodynamic effect of coupling train-tunnel-station was established.The results indicate that 550 meters for the length of separating walls,800 meters for the length of station-tunnel transition sections,and ventilation shafts set at four ends of two platforms with an area of 36 m~2 are the optimal solutions for mitigating aerodynamic effects.By combining these optimal solutions,an optimal matching model for mitigating aerodynamic effects was obtained.The optimal matching model significantly reduces the pressure peak on the surface of trains and platform screen doors,as well as the peak of slipstream on the arrival-departure track operation areas.The structural safety of platform screen doors under aerodynamic load generated by high-speed trains passing through underground stations was evaluated.The finite element analyses of the structural response and fatigue life of platform screen doors exposed to aerodynamic loading from high-speed trains passing through the station was carried out.The natural frequency and vibration modes of platform screen doors were elaborated,and the influencing mechanism of strong loads on the stress distribution,deformation characteristics,fatigue damage,and life of platform screen door structures was revealed.Additionally,the influence laws of aerodynamic load optimization and platform screen door structure optimization on the maximum stress and maximum deformation of the platform screen door was clarified,ensuring that the structural strength,stiffness,and fatigue life of the platform screen door under the optimized station model meet the design requirements.It is found that both aerodynamic load optimization and platform screen door structure optimization can ensure the structural safety of the platform screen door system.Fixed door frames are the most dangerous parts of platform screen door structures for fatigue damage.The optimized station model significantly alleviates the structural response and fatigue damage of the platform screen door,greatly improving its fatigue life and ensuring its structural safety fully meets the design requirements.There are totally 125 Figures,32 Tables,and 209 References.