Bearing deformation of large-diameter and super-long bored piles based on pile shaft generalized shear model

Because of large deformation of large-diameter and super long bored piles, pile soil slip is easy to appear in the pile shaft. Therefore, the traditional shear displacement method is not suitable for load deformation calculation of the piles. According to the shear characters of pile shaft and soils of the large-diameter and super long bored piles, the two-phase approach, shear displacement phase and shear slip phase, is adopted to describe the action process of pile shaft friction. On this account, a pile shaft generalized shear model is established. Then, the method of incremental transfer matrix is used for nonlinear iterative calculation of the pile load deformation. Moreover, values of the same calculating parameters are also given. For this pile load deformation method, nonlinear behaviors of pile shaft friction, pile tip resistance and pile shaft materials are considered. Besides, pile shaft friction softening property and pile tip post-grouted effect mechanism are also considered. Two engineering cases are calculated by the method. The calculated and measured results are very similar. It is shown that the proposed pile shaft generalized shear model and load deformation method for the large-diameter and super long bored piles are reasonable and feasible.