路基上双块式无碴轨道道床板空间力学特性研究

In this paper, the spatial mechanical characteristic of track concrete layer of twin-block ballastless track on subgrade under different loads is studied. A spatial finite element static model of twin-block ballastless track on subgrade is established, in which both rail and steel bar were modeled as beam element, track concrete layer, twin-block sleeper and support layer were modeled as solid element, the connections between rail, track concrete layer, support layer and subgrade are modeled on spring element. The spatial mechanical characteristic of track concrete layer under gravity load, vertical train load, uneven settlement load as well as temperature gradient load was analyzed. The results show that the effect of temperature gradient load to concrete tensile stress is most significant. The steel bar longitudinal tensile stress may be larger than 20 MPa under vertical train load, uneven settlement load or temperature gradient load. The effects of variation of support layer thickness, support layer elastic modulus, and track concrete layer thickness to concrete and steel bar mechanical characteristic are different. The concrete and steel bar longitudinal tensile stress increases with the increase of crack interval.