Analytical method for load-transfer characteristics of rock-socketed drilled shafts

The load-settlement behavior of rock-socketed drilled shafts under axial loading is investigated by a load-transfer approach. Special attention is given to the shear load-transfer function and an analytical method for estimating load-transfer characteristics of rock-socketed drilled shafts. A nonlinear triple curve is employed to determine the shear load-transfer function of rock-socketed drilled shafts based on the constant normal stiffness direct shear tests and the Hoek-Brown failure criterion. An analytical method that takes into account the soil coupling effect was developed using a modified Mindlin's point load solution. Through comparisons with field case studies, it is found that the proposed methodology in the present study is in good agreement with the general trend observed by in situ measurements and, thus, represents a significant improvement in the prediction of drilled shaft shear behavior.