Ultimate lateral resistance of piles in sand based on the modified strain wedge model

This paper proposes a novel method for calculating the ultimate lateral resistance exerted by sandy soil against laterally loaded piles. The ultimate lateral resistance distribution of the pile on the front side of the pile above the rotation point is determined by a modified strain wedge model with the three-dimensional cone shape, while the ultimate lateral resistance on the back side of the pile below the rotation point is calculated according to the theory of the passive earth pressure. Using the proposed distribution form of the ultimate lateral resistance along the pile length, an explicit expression to calculate the ultimate bearing capacity is obtained based on the limit equilibrium principle. The rationality of the proposed method is verified by several laboratory and field tests from published literature, and the comparative analysis show that the prediction results coincide with the experimental results. The variations in the normalized modified strain wedge shape depth, radius and ultimate bearing capacity of the pile with the change in the relative stiffness are deeply explored by using the proposed method, and some fitted expressions to quickly determine the modified strain wedge shape and estimate the ultimate bearing capacity of different piles are obtained.