Research On Transmission Property Of Interlaminar Structure By Composite Specimens For Twin-Block Ballastless Track

Slab track, whose main components are made of concrete, emulsified asphalt cement mortar and other cementitious material, has been widely used in high speed railways of China. The structure design is based on the hypothetical interlaminar structure and supporting system, under the long term action of dynamic train load and temperature load, the interlayer bonding state will be changed, and then the the actual stress and degradation rate will be effected, however, the mechanism of interlaminar damage is lack of research. Therefore, research on the mechanical behavior of interlaminar structure is of great significance for the design of slab track structure and exactly grasping the evolution within its life cycle.First of all, for the problem of loosen sleeper in twin-block ballastless track, tensile and shear tests of concrete composite specimens with two kinds of interlayer types has been put on plan in this paper, and the failure mode has been analyzed. The results shows that the strength of interlaminar structure is significantly reduced because there are some tiny pores and microcracks, and according to the mechanical interaction when shear failure, the shear strength is greater than the tensile strength。Splitting tensile strength were 1.97MPa (rough), 1.16 MPa (smooth), the shear strength of 3.68MPa (rough),1.89MPa (smooth). These shows that interlaminar structure can be enhanced when roughedSecondly, the stretching and shear stress-strain curves show that interlaminar structure belongs to the elastoplastic structure when subjected to tension, at first, it is elastic, when the stress reaches half of the peak value, it turns to plastic, elastic modulus gradually decreases.When subjected to shear, the interlaminar structure belongs to the elastic structure,finally, two cohesion models were built to simulate tensile and shear tests of concrete composite specimens, and the parameters of interlaminar structure were analyzed, The results shows that when the fracture energy Gci was12-15N/m (rough) and about 2.5N/m (smooth), GCⅡ was38-42N/m (rough) and 14-19N/m (smooth), the load-displacement curve and the stress distribution was consistent with the test results. The fracture energy values are reasonable and reliable at this time.