Analysis Of Buffer Effect Of Inline-throuth Buffer Structure

In recent years,due to the rapid development of China’s high-speed railway technology and tunnel technology,it is inevitable to build tunnels in mountainous areas,but the high speed of the train into the tunnel will make the air inside the tunnel is squeezed to form the initial compression wave,causing a dramatic change in pressure,which leads to a series of tunnel aerodynamic problems such as train operation safety,passenger comfort and train body structure.This thesis is based on the installation of an interconnected buffer structure in the tunnel,so that the compression wave is reflected between the train,the interconnected buffer structure and the tunnel several times,which reduces the pressure gradient of the compression wave and delays the time for the compression wave to reach the maximum pressure value,in order to alleviate the tunnel aerodynamic problems.In this thesis,the k-ε two-equation turbulence model and slip grid technique are used to simulate the aerodynamic pressure inside the tunnel cavity when a high-speed train passes through a tunnel with an interconnected buffer structure.The simulations were performed by varying the train speed(250km/h,300km/h,350km/h,400km/h),the location of the inline buffer(10m,20 m,30m from the tunnel entrance),the size of the inline buffer section(1m~2,4m~2,9m~2),the size of the two The parameters such as the different setting positions of the interconnected buffer structure(30m+60m,30m+100m,30m+300m),and the time course curves of pressure and pressure gradient at different measurement points in the tunnel were analyzed to study the variation law of pneumatic pressure in the tunnel cavern.The research results show that:(1)When the position of the internal connected buffer structure is fixed and the train speed is fixed,the larger the breaking area of the internal connected buffer structure is within 9m~2,the better the buffer effect on the aerodynamic effect of the tunnel is.(2)When the section size of the internal connected buffer structure is constant and the train speed is constant,within 30 m of the setting position,the farther the setting position of the internal connected buffer structure is from the tunnel entrance,the better the buffer effect on the tunnel aerodynamic effect is.(3)When the position of the internal connected buffer structure is fixed and the section size is fixed,the aerodynamic effect of the tunnel gradually increases with the increase of the train speed.(4)Under the condition of keeping the train speed 350km/h unchanged,the buffer effect of the two internal connected buffer structures is more obvious than that of the one internal connected buffer structure,and the closer the position of the second buffer structure is set to the tunnel entrance,the better the buffer effect.