So, in the same bolttension narrow narrow smooth after the pressure stress increases.
这样，在螺栓张力相同的情况下，缩小后的窄光滑面的压紧应力就会增大。
2
It is difficult to pull out the bolt with ordinary socket wrench that can not provide axial tension because of the bolt drilling hole deformation and the collapse of holes.
As the bolttension increase, the tension of rail web, stress of joint bar and stress of joint bolt would increase accordingly, but the displacement of rail would become smaller.