Effect of Slab Void on Mechanical Properties of Longitudinal Connected Ballastless Track

According to structure characteristics of longitudinal connected ballastless track on subgrade and the theory of beam and plate on elastic foundation, three dimensional finite element analysis model of train load and longitudinal connected ballastless track system was derived. And the effect rule of different condition on slab void on mechanical properties of longitudinal connected ballastless track on subgrade was analyzed. The results show that mechanical response values under train load function, such as bending moment and displacement of track slab and HGT, grow with the increasing void. When void width increases to 2.55m and void length increases to 1.19m, the maximum value of longitudinal tensile stress of track slab reaches tensile strength of concrete and cracks of pre-crack of track slab appears. Then, compared to non-void status, the maximum values of longitudinal compression stress, vertical displacement and longitudinal positive moment of track slab are respectively 1.49 times, 1.45 times and 1.59 times. Therefore the combination of track slab and mortar should be ensured in good condition in construction and maintenance of ballastless track, and this can improve its mechanical properties state and prolong the service life.