Study On Dynamic Behavior Of Vehicle-Slab Track System Under The Subgrade Frost Heaving In Cold Region

Subgrade frost heaving in cold region could cause the damage and irregularity of the ballastless track structure and it directly effects the safety and stability of the vehicle.It is a key technical problems in the construction of high speed railway line in cold region.Frost heaving of subgrade is a key factor which could cause the deceleration operation of high speed railway line in cold region and it is a main factor to increase the workload of the track maintenance.In the existing research,los of work focus on the mechanism and control measurement of subgrade frost heaving,but little research focus on the vehicle-track dynamic behavior under the subgrade frost having especially on the relationship between frost heaving and track irregularity and the dynamic response of vehicle track interaction relationship.A series problem which relate to the irregularity of slab tack and dynamic character of vehicle which caused by frost heaving is urgently to solute.In this paper,the co-simulation method is used which include the finite element software ABAQUS and multi-body dynamic software SIMPACK.Analysis model of vehicle track rigid flexible coupling dynamic was established and vehicle-track dynamic behavior which is effect by various wave length and amplitude of the single wave and multi-wave of frost heaving is studied-In the same time,by using the subroutine of ABAQUS,the dynamic response of substructure in the condition of the frost heaving which under the vehicle moving load is researched.At last,the vehicle-track dynamic behavior and vibration character of substructure that was effect by different parameter of railway line is researched.The main research work and achievements are as follows:(1)The refinement vehicle model is established by SIMPACK software and the refinement algorithm of wheel-rail contact relationship is adopted.The flexible model of railway line is established by ABAQUS software and the modal information and substructure of railway line is calculated.The vehicle-track rigid-flexible coupling dynamic model is established through the interface of FLEXTRACK function in SIMPACK.(2)The discipline that the safety and stability of vehicle which is effected by single wave and multi wave is revealed.The safety and stability of the vehicle is obvious effected by frost single wave and period frost multi-wave.Whether frost single wave or period forst multi wave,with the increasing of wave length,the vertical wheel rail force,lateral wheel rail force,derailment coefficient and reduction ratio were decreased.The longer the wave length is,the safety of the vehicle is.The vibration acceleration of the vehicle decreased with the increasing of wave length.For the period multi wave,the sensitive wave length of frost heaving is in the range from 10m to 20m.In the frost heaving area.(3)The chatacter of the substructure of rail under the moving load in frost heaving region is analyzed.Under the moving load of the vehicle,with the increasing of the wave length,the dynamic response of the track structure decreased.The bigger the frost amplitude is,the bigger of the dynamic response of the track structure is.No matter single wave or period wave,the index of displacement,stress and vibration acceleration of track structure is decreased with the increasing of the wave length.And the bigger the frost amplitude is,the bigger of the dynamic response of track structure is.In the condition of the frost heaving.(4)The character of vehicle-track-subgrade dynamic response effected by parameter of railway line is researched.With the increasing of the vehicle velocity,the vertical wheel rail force and lateral wheel rail force is increased gradually and the dynamic response of the track structure which include the displacement,stress and acceleration is also increased.For the stiffness of the fastener,the bigger the stiffness of the fastener is,the bigger of the wheel-rail vertical force and wheel-rail lateral force is.The derailment coefficient and wheel load reduction rate remain unchanged with the increase of the fastener stiffness.The vertical vibration acceleration increases with the increase of the fastener stiffness.The vertical displacement and vertical stress decrease with the increase of the fastener stiffness.The vertical vibration acceleration,displacement and stress of the track slab and subgrade do not change with the change of the fastener rigidity.