Analysis of compacting effects of tubular pile based on unified strength criterion with parabolic failure envelope

Based on the unified strength theory with parabolic failure envelope, the nonlinear improved expression of the two-parameter twin shear unified criterion is presented. According to the cavity expansion theory, compaction effects of the tubular pile is studied. The elasto-plastic analysis solution of the stress field and displacement field of the soil around the pile are formulated. The results show that the parameter b in unified strength theory has effects on the radius of plastic zone and the magnitude of stresses and displacement. With the increasing b, the radius of plastic zone is decreased and the radial displacement and the limit expansion pressure are increased, at the same radius, the radial stress is also increased.