STUDY ON THE INTERACTION OF WHOLE BONDED ROCK BOLT AND TUNNEL SURROUNDING ROCK

A new computational model for rock bolt has been developed, and its physical, geometrical and equilibrant equations have also been built. On the basis of this model the distribution of internal force along the bolt with interface slipping was analyzed. This model indicates the essences of the interaction between bolts and homogeneous surrounding rocks, describes the internal force of bolt as the function of surrounding rock displacement. Combined with finite element method, internal force distribution in complex conditions can be obtained, and the bolt’s action on the surrounding rock is equal to a group of nodal loads that are applied to the surrounding rock nodes. A sample computation shows that bolts can reduce the displacement and plasticity zone of surrounding rock, and the internal force distribution and neutral point site are affected by bolt length, burying site, surrounding rock conditions, bonding intensity, and so on. The proposed model provides a new way to determine reasonable parameters for rock bolt supporting.