Experimental study on the effect of bolt prestress on the shear behavior of jointed rockmass.

Concrete was used to simulate the real rock. The effects of bolt prestress on the shear behavior of jointed rock mass were studied with the approach of joints directly shearing in laboratory and situ. The results show that as the prestress improved, the initial shear stiffness of the rock mass is improved, playing an important role in inhibiting the early deformation of the surrounding rock and improving the performance of bolt supporting; As the prestress increased, the jointed rockmass presented phased characteristics, including three stages, such as rapidly increasing resistance, slowly increasing resistance and resistance reduction characteristics; Situ tests show that bolt resistance could be enhanced when the bolt prestress improved and highly-pre-stressed fully-encapsulated rock bolts achieved good results for jointed rock supporting. [ABSTRACT FROM AUTHOR]