Laboratory Investigation on Shaft Resistance of Rock-socketed Pile

The ultimate bearing capacity of rock-socketed pile in granite is so large that make it too difficult to monitor the distribution of shaft resistance along the pile under ultimate load in field tests. In this paper, three groups of model piles were used to investigate the effect of rock-socketed depth, rock joint inclination and pile stiffness on shaft resistance. Test results show that an optimum socketed depth and pile stiffness existed for rock-socketed piles. The shaft resistance of rock-socketed piles in granite with joint development was significantly reduced. It was found that the optimum socketed depth of rock-socketed pile in slightly weathered granite was 3D, and the shaft resistance under different rock-socketed depths all presented a non-uniform distribution of large upper and small lower. Rock joint inclination increased from 0° to 30°, the displacement of pile top increased significantly, and the ultimate shaft resistance decreased. With the increase of pile stiffness, the distribution of shaft resistance along the pile was more uniform. The experimental results can provide a reference for bearing capacity analysis of rock-socketed piles installed in high strength rock strata with developed joints and fissures.