Study On Effect Of Flow Field Characte-ristics Of Bridge Wind Fences Structure On The Strong Wind And Sand

The Second Lanzhou-Xinjiang railway Line is one of the Gobi Railways with the most windy areas and the longest mileage in the world.Due to the unique geographical location and climate environment,the ecological environment of the Gobi area in Northwest China is very sensitive and fragile.Affected by topography and human activities,there are many high wind-hazardous areas in the Gobi area.Gale disasters on the Xinjiang section of the Second Lanzhou-Xinjiang railway Line are mainly distributed in high wind areas such as Hundred Miles,Thirty Miles,and Dabancheng,which seriously affect the safe operation of high-speed trains.Second Lanzhou-Xinjiang railway Line is often exposed to strong winds,sand and dust.The aerodynamic characteristics of high-speed trains running on bridges will be more affected by extreme winds.Therefore,it is imperative to study the wind and sand resistance performance of bridge wind grids in strong wind and sand areas.Firstly,based on the investigation and verification of the specific wind-sand environment in the Gobi wind area,with the Second Lanzhou-Xinjiang railway Line bridge windbreak project in the Gobi area as the background,according to the characteristics of the Second Lanzhou-Xinjiang railway Line operating in the Gobi wind area,a full-size bridge wind fence was established Model and verify the rationality of the numerical simulation program.Secondly,a numerical simulation of the wind-sand flow field around the bridge wind fences in the Gobi area is carried out.Analyze the flow field around the wind fences of the bridge in the Gobi gale area with different layouts and different wind-sand velocities.Furthermore,by measuring the flow field and wind-proof efficiency of the front and back of the double-sided wind fences,numerical simulation is carried out on the wind-sand flow field of wind fences with different porosity and wind-sand flow velocity.The influence of wind-sand flow on the response law of wind fence and the wind-proof characteristics and effects of wind fence under different wind-sand velocity and different porosity are studied.At last,a comparative analysis of the flow field around the bridge’s wind fences with or without trains in a pure wind environment and a wind sand environment.The distribution of pressure,velocity cloud diagram and velocity streamline diagram around the bridge and the wind fence under different porosities is analyzed,and the influence of the bridge wind fence on the operation safety of high-speed trains is initially discussed.