Random field model of soil parameters and the application in reliability analysis of laterally loaded pile

Abstract

The bearing capacity of pile under horizontal load is not only related to pile size and pile material, but also closely related to soil parameters. In this paper, based on the probability analysis method of random field theory, a non-stationary random field model is firstly proposed for the undrained shear strength Su of soil. In this model, the uncertainty of the increase trend of Su along the direction of depth is taken into account, and the mean value and standard deviation of random field increase linearly along the depth. Then, by comparing with other random field models, the applicability of the non-stationary random field model for undrained shear strength proposed in this paper is verified. Finally, the random field model is applied to the reliability evaluation of horizontally loaded pile, and the influence of the spatial variability of undrained shear strength on the failure probability of horizontally loaded pile is discussed. The results show that the coefficient of variation and correlation length of undrained shear strength have obvious influence on the failure probability of pile foundation. The uncertainty of increase rate b of undrained shear strength with depth also has influence on the failure probability of pile foundation. If the spatial variability of the soil parameters is not considered in the evaluation and design of pile foundation, the failure probability of pile foundation will be large, which will make the design results of pile biased toward conservative.