The radial deformation of the rushed stone pile in the soft foundation was discussed and the pile s different deformation mode in the vertical and horizontal was presented,as the result of it,the pile soil stress ratio expression is established on the principle of continuity and harmony of the stress strain of composite ground by Visic curvity expansive theory and p y curve method.

Considering the plugging effect of the pipe pile,the cavity expansion theory is applied to studying the squeezing effect of pipe pile.

Based on the squeezing effect in the process of pile sinking,the squeezing behaviour of concrete-cored sand-gravel piles is analyzed by applying cavity expansion theory and consolidation theory.

The cavity expansion theory used for plane problems is extended to the spatial axisymmetric condition to improve the analytical solution of soil displacement induced by pilesinking.

The radius of plastic area, the maximum compress stress caused by driving pile ,and the pore water stress can be concluded by using the cavity expansion method and the effective stress theory.

Reviewed are five methods for the analysis of the penetration of jacked in piles,namely,cavity expansion method,strain path method finite element method,slip line method and calibration model test.

After analyzing the general calculation methods of pile-soil stress ratio and pointing out their defects,this paper derived a new formula to calculate the stress-strain of pile and soil in loading process by using the theory of round-hole expansion and the harmony condition.

The theory of round-hole expansion was used to simulate the mutual actions between pile and soil.

Two constitutive relations(linear elastic model and ideal elastic-plastic model)and two pile-drivien process s simulation modes(stress boundary conditions method and cylindrical cavity expansion theory)are adopted and combined respectively to compute.