Effect of Rock Bolt on the Strength of Jointed Rock

Srivastava, Lok Priya (IIT Roorkee) | Singh, Mahendra (IIT Roorkee)



The main aim of the present research work is to investigate the effect of joint orientation on the strength and modulus enhancement of the jointed rock due to provision of rock bolts. Laboratory tests have been carried out on the jointed rock specimens (without and with rock bolts) of size 15 cm x15 cm x 30 cm (height) under uniaxial compression. Steel bars of 6 mm diameter were used as rock bolts, which were grouted with 4 mm thick cement mortar. The joint orientation of specimens was varied from 0° to 90° with respect to loading direction. The bolts were installed normal to loading direction. The results from tests indicate that in general the strength and modulus of jointed rock increase due to rock bolts for all joint orientations. However, for critical joint orientations (θ=45° and 60°) the enhancement was quite large due to change in failure mode. Also there was reduction in extent of anisotropy of the jointed rock both in strength and deformation modulus.