Track Slab Adjustment Scheme In Xi'an Ground Fissure And Its Dynamics On Vehicles And Track Systems

Xi'an is one of the cities with the most serious ground fissure disasters in China.and 14 ground fissure zones have been discovered in the urban area.With the rapid development of Xian urban construction,the construction of subway is the key to urban development.However,the planning and construction of the subway is Unlike other construction projects,the ground fissure zone is avoided.The vertical deformation on the upper and lower sides of the ground fissure is not synclironized.resulting in relative displacement,which causes the rail plate to be unstable or suspended on the side of the descending zone,5o that the track structure is stressed Abnormal or even damage will directly affect the safety of vehicle passing.Therefore,finding an engineering solution to solve the subway over-fracture section has become the top priority of Xi'an subway construction.At present,the track structure of the ground fissure section adopts the connection scheme of the adjustable frame plate and the heightening pad through the concave and convex nesting and bonding,but the solution has the problems of the adhesive falling off and the nesting place cannot ensure the closeness,and the vehicle passes through.The height-adjusting pad is easily broken under the action of load and vibration.To this end,a new bolt-type connection scheme is designed,and an adjustment scheme for the height-adjusting block corresponding to the ground settlement is proposed.The static analysis of the frame plate and the height-adjusting pad was carried out in the ANSYS Workbench finite element analysis software.The calculation results show that the maximum equivalent stress of the adjustable frame plate is 11.01 MPa,and the maximum overall deformation is 0.063 mm.The maximum equivalent stress is 10.80 MPa,and the maximum overall deformation is 0.014 mm.The concrete design used in the current design meets the requirements for use.The effects of different support spacings of the height-adjusting pads on the maximum dynamic sinking of the rails and the maximum bending moment of the frame plates are studied.The arrangement spacing of the height-adjustable blocks is optimized by using 1425mm as the optimal adjustable frame board.Using UM multi-body dynamics software,the vehicle-orbit model and the track irregularity disturbance model of the ground fissure section are established.The dynamic evaluation index is selected to analyze the influence of the ground fissure settlement and the vehicle running speed on the dynamic performance of the vehicle and the track system.The calculation results show that when the running speed of the vehicle is 80kmnh and the settlement reaches 40mm,the relevant index exceeds the limit.The track system should be adjusted according to the adjustable frame-fitting adjustment scheme of the ground crack section.When the speed limit of the ground fissixre zone is 40km/h,and the local crack settlement is greater than 60mm,the running speed of the vehicle shall not exceed 40km/h.The vehicle-track-Multistory foundation basic coupling dynamics model was created by using ANSYS finite element analysis software and UM multi-body dynamics software.The influence of the void of the track plate caused by different numbers of height-adjusting blocks on the dynamics of the vehicle and the track system is analyzed.The results show that the vibration response of the vehicle system has no obvious reaction to the void of the frame plate,so it is in operation.It is advisable to strengthen the line inspection;the effect of adjusting the frame plate on the frame plate and the track system is serious.If the number of empty cranes increases,the vertical deformation of the track structure will be too large,and the long-term cumulative deformation will lead to the increase of the track irregularity.,affecting the safety of subway vehicles.