Distribution of shaft resistance of rock-socketed piles based on mechanical properties of pile-rock interface

Considering the bond strength of pile-rock interface, a full shear mechanism of rock-concrete interface of rock-socketed piles is proposed, which includes bond damage, sliding dilatancy and shear slipping, and pile shaft resistance mainly consists of bond strength and friction. According to the mechanical properties of joints at different shear stages, the function of a complete constitutive model for rock-concrete interface is founded, and its load transfer equation is explored as well. On the basis of its analytic solution, the distributions of frictional resistance and axial force along the pile length are discussed, which can theoretically explain the distribution law that has single or double-peak shaft resistance value. The analysis results indicate that the traditional distribution location, such as 0.15l or 0.75l does not exist, and that the position of the double-peak shaft resistance values moves down gradually along the pile with the increase of the load, and that the form of single-peak appears when the load exceeds its critical value. The results of comparing the theoretical analysis with the engineering case show that the analytic solution is reasonable and feasible.