The main function of self drilling rock bolt in concrete structure is bear tensile force to cover poor performance of tensile strength and shortage of ductility.
Structurally, self drilling rock bolt is divided into anchorage section in rock body, free section between rock body and free section in concrete. Intense water pressure between concrete and rock body may be transferred directly into acting force between self drilling rock bolt and concrete.
With the load increase on self drilling rock anchor, the maximum displacement of bond stress between self drilling rock bolt and slurry body moves down to the fixed segment, slides in gradual way and distributes in the way of changing bond stress. Initially, adhesive force has effect near anchoring segment. When adhesive force is overcome, slide will be produced and most bond stresses will be transmitted to the far side of anchoring segment, then friction force at near side has little effect.
During rock body’s diastrophism, self drilling rock bolt’s stress and deformation mainly focus nearby from discontinuous surface, forming obvious curvature here, which is called railway function of self drilling rock bolt. It has great perniciousness for anchoring effect and also it may be a breakthrough point.
In general, self drilling rock bolt’s anchoring mechanism and mechanical characteristics are complex under various factors. It needs further research according to specific and different engineering.