Theoretical Analysis on the Vertical Bearing Characteristics of Pile Foundations Containing Sediment Defects

Aiming at the situation that the bottom of the pile foundation contains sediment defects, the theoretical analysis of the vertical bearing characteristics of the pile foundation is carried out. Based on the load transfer mechanism of the pile-soil system and based on the load transfer function of the elastoplasticity of the soil on the side of the pile and the weakening of the trifold line of the soil at the end of the pile, a load transfer calculation model for bored cast-in-place piles with slag defects under different conditions was established. The corresponding analytical formulas are deduced, and the accuracy and reliability of load transfer derivation are verified in combination with calculation examples, which are suitable for indoor and field tests. The influence coefficient of sedimentary defect in single pile is defined, and the parameters are analyzed. The law about the influence coefficient of length-diameter ratio, the thickness of sedimentary defect, and the modulus of elasticity of sedimentary defect in single pile are obtained: With the increase of the ratio of length and diameter, the defect coefficient of single piles gradually increases and tends to ease, and the bearing effect of pile foundations is more convergent. As the thickness of the sediment increases, the influence factor of the single pile defect gradually decreases, and the influence factor of the bearing capacity of pile foundation becomes more discrete. With the increase of the elastic modulus of sediment, the influence factor of single pile defect gradually increases, and the ultimate bearing capacity loss decreases. The vertical bearing characteristics of the pile foundation are evaluated in this way, which provides an important reference for further analysis of the bearing characteristics of pile foundations with slag defects.