The rock bolt was applied widely in the tunnel construction. However, the traditional equilong rock bolt can not connect the surrounding rock effectively in the nearly zone and the shear stress on is so large to lead to the length limitation. While the combination of the long rock bolt and the short rock bolt can foster strengths and circumvent weaknesses. The supporting effect is definitely better.
In the combining support of the long rock bolt and short rock bolt, the former on one hand controls the deformation of surrounding rock except the reinforced composite arch. On the other hand, it can reinforce the combination arch structure to hang on the stable rock for coordinate deformation of surrounding rock.
Relating to the short rock bolt, it can reduce the hulking deformation of the rock and the further damage of the fracture by limiting the deformation of the near area and the development of the fracture surface. The short rock bolt can also form reinforced composite arch structure which has a certain bearing capacity near tunnel surrounding rock. All these can strengthen the integrity and stability of the surrounding rock effectively.