Analysis On Warping Effect And Influencing Factors Of CRTS Ⅱ Slab Ballastless Track

The slab ballastless track structure occupies an important role in our country’s high-speed railway lines,but there are many problems in the use procession.Among them,the warping deformation of the track slab due to the temperature gradient load has always been one of the prominent diseases of the CRTS Ⅱ slab ballastless track.According to the characteristics of CRTS Ⅱ slab ballastless track structure,the finite element software is used to establish the calculation model which can be used to study the warping effect of track slab,and various influencing factors are fully considered.The warping deformation and mechanical property change rules of track slab are summarized,which is of great significance for the design and optimization of track structure to our country.The main work of this paper is as follows:(1)Combining the construction characteristics and force mechanism of the longitudinally connected slab ballastless track structure,it is divided into unit stage and longitudinally connected stage for analysis.At the same time,it is assumed that the interaction between the track slab and the CA mortar is completely debonded and completely bonded,respectively,the deformation and stress differences under different working conditions are discussed.Studies have shown that: when the track slab is completely debonded from the CA mortar,the track slab warping deformation is larger;the longitudinal connection has a significant effect on suppressing the warpage deformation of the track slab;at the same time,due to the larger temperature load on the upper surface of the slab and the strong constraint on the track slab in the fully bonded state,the stress on the upper surface of the track slab is larger in the fully bonded state.(2)The influences of external factors such as rail constraint,overall temperature,train load and different underlying foundations on the warping deformation and longitudinal stress of track plate were investigated.The research shows that the rail restraint has little effect on the warping deformation and longitudinal stress of the track slab;when the upper surface temperature is close to the construction temperature,the warping deformation of the track slab is the smallest,and the overall temperature change of the structure has a greater influence on the longitudinal stress in the slab;when the train load acts on the middle of slab,the deformation constraint is greater,while when the train load acts on the end of slab,the longitudinal stress is greater;the warping deformation of track slab on subgrade is larger,and the longitudinal connection effect is stronger on the warpage deformation of track slab on subgrade,while the longitudinal stress in slab is mainly caused by temperature load and has little relationship with foundation conditions.(3)Comprehensive analysis of the effects of different CA mortar elastic modulus,track slab elastic modulus,track slab thickness,wide and narrow joint damage state on track slab warping deformation and longitudinal stress,and provide reference for the optimization and maintenance of track structure design.Research shows that: different CA mortar elastic modulus has little effect on the warping deformation and longitudinal stress of the track slab;the warping deformation and longitudinal stress of the track slab have a positive correlation with its own elastic modulus;the greater the thickness of the track slab,the smaller the warping deformation,but the greater the longitudinal stress;when the wide and narrow joints are damaged,it will seriously affect the deformation and stress of the track slab,especially when the wide joints are damaged,the track slab is in an extremely unfavorable state.Therefore,when the wide and narrow joints are damaged,they should be repaired in time.