Estimation of the installation torque–capacity correlation of helical pile considering spatially variable clays

Abstract

As the offshore industry moves into deeper water, helical piles are emerging as a potential foundation solution option. A large number of studies have been published to explore the installation torque-capacity correlation. However, in most previous studies, the inherent spatial variability of soil strength was neglected. The present research explores the installation and extraction behavior of helical piles through a large deformation random finite element method. A strain-softening soil constitutive model proposed in past literature is employed to model the soil strength remoulding. The validity of the numerical model used to simulate the installation process and the subsequent uplift process is verified by the installation torque and the uplift capacity, respectively. The spatial variation of soil strength is modeled using random field, and then a series of Monte Carlo simulations are performed to investigate the torque-capacity correlation of the helical piles under different random realizations. The analysis results show that for the helical piles with different penetration depths, the spatially random soil strength markedly affects the torque-capacity correlation. Moreover, a probabilistic analysis of the torque-capacity correlation is conducted, which may be of great interest to engineering practitioners in the design method of the helical pile.

Sensitivity Analysis of Different Factors in the New Pipe Curtain Freezing Method under Seepage Conditions

“…Finite element analysis is widely used in geotechnical engineering [25][26][27][28][29][30], and the commercial finite element software COMSOL is used in this study. When conducting the three-dimensional modeling of the new pipe curtain freezing method, the width and height of the excavation area within the pipe curtain freezing pipe are 18.8 m × 21 m. The odd-numbered pipes are solid top pipes filled with concrete and arranged with circular freezing pipes; the even-numbered pipes are freezing pipes with irregular freezing pipes arranged inside.…”