New calculation method for the settlement of long-short-pile composite foundation based on virtual soil-pile model

In the existing standards, there are still some insufficient considerations of the pile end soil and the mutual reinforcing effect between piles when computing the settlement of long-short-pile composite foundation. For fully considering the mutual reinforcing effect, the thin-ring cylinder shear model and the shear displacement method are adopted in this paper. Besides, the relationship between the settlement and axial force of the solid pile and the virtual soil pile is obtained in process by applying the virtual soil-pile model to considering the stress and deformation of pile end soil. It proposes an improvement of the interaction coefficient between the long and short piles and is applied to the analytical solution for the settlement of long-short-pile composite foundation. Compared with experiments, the error between results of two methods is only 4.65%, which indicates that the proposed method can accurately calculate the settlement of long-short-pile composite foundation. Meanwhile, the measured values are compared with the analytical and simulated values, and the results of three methods have good consistency, which further verifies the correctness and applicability of the analytical method in this paper.