Experimental study on mechanical and deformation properties of rail WJ-8B type fastener system in longitudinal push-out

A longitudinal push-out test of the prototype full-size rail-WJ-8B fastener system was carried out, and eight various torque of bolts were considered. Through the whole process analysis of rail push-out test, key indicators such as nominal yield force, nominal yield displacement, peak resistance and stiffness of rail-fastener system were obtained, the results show that in the push-out process, no obvious damages were occur to each component of the fastener system, and the worst damage was only manifested in the surface scratches of the insulated gauge block; the resistance-displacement of the rail-fastener system presented three obvious stages, namely, the elastic stage, the nominal damage stage, and the nominal failure stage. Under different torques, the nominal yield displacement was basically kept around 1.5 mm to 2.5 mm. When the torque of fastener was 110N m (small resistance), the nominal yield force was 4.20kN and the peak resistance was 5.05kN; when the torque was 160N m (the constant resistance), the nominal yield force was 5.52kN and the peak resistance was 7.48kN, and the nominal yield force increased by 1.32kN, an increase of 31%, and peak resistance increased by 2.43kN, an increase of about 48%. When the longitudinal displacement of the rail reached to 20mm, the longitudinal resistance of the fastener system under different cases decreased with the increase of the displacement of the rail, and the rail-fastener system was considered to enter the nominal failure stage. Finally, the resistance- displacement mechanical model of WJ-8B fastener system was deduced.