Study on the Deformation Effects of Foundation Pit Retaining Piles in the Influence Zone of the Footwall Affected by Reverse Fault

Abstract

Abstract In order to investigate the deformation characteristics of the retaining piles in the footwall affected by reverse fault, this study focuses on a case study of a foundation pit project in Shenzhen City, using numerical simulation methods. By analyzing the deformation characteristics of the retaining piles under reverse fault and investigating the influence of different fault slip amounts, dip angles, and positions on the pile deformation, sensitivity analysis and orthogonal experiments of fault parameters were conducted. The research results show that the deformation of the retaining piles under reverse fault exhibits an increasing trend, with the center of gravity shifting upward. Regarding the deformation impact, the upper part of the pile shows significantly larger deformation than the lower part, especially at the pile top. The overall deformation of the pile exhibits an approximate spoon-shaped curve, with the maximum deformation occurring in the middle to upper part of the foundation pit. The deformation of the pile is directly proportional to the fault slip amount and dip angle, while it is inversely proportional to the distance from the fault to the pit. Furthermore, the maximum deformation rate r(ΔZmax/Δ) increases non-linearly with increasing fault slip amount and dip angle, and decreases non-linearly with increasing distance from the fault to the foundation pit. Through sensitivity analysis of fault slip amount, dip angle, and position on the maximum deformation of the retaining pile, it is found that the dip angle has the greatest influence on deformation, followed by the slip amount, while the fault position has the least influence. By fitting the data from 64 orthogonal experiments, a good linear relationship is established between the maximum deformation Uhm of the retaining pile and the index η(\(\frac{{\theta \pi T}}{{{{180}^^\circ }S}}\) ). Furthermore, a predictive model is developed for the maximum deformation of the retaining pile in the influence zone of the footwall affected by reverse fault. This study provides valuable references for controlling deformations in foundation pit projects in reverse fault areas and holds significant importance for rational design and construction. The research findings contribute to reducing geological hazards, ensuring engineering safety, and promoting the sustainable development of foundation pit projects. Moreover, these contributions play a positive role in minimizing environmental impacts, resource consumption, and advancing the sustainability of engineering practices.