Influence of grouting pressure volatility on additional response of adjacent pile foundation in shield construction

Abstract

Soil parameters along the heading direction are subjected to spatial variability during shield construction, so grouting pressure requires constant adjustment to ensure ground stress stability. This causes grouting pressure to fluctuate around the design pressure/curve. Therefore, the influence of the grouting pressure volatility on the adjacent loaded-pile foundation should be considered in shield tunneling. In this study, a refined numerical simulation of the shield construction process is conducted using the Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D) software. A total of 300 groups of grouting pressure parameters with a skewed normal distribution are input into the numerical model. Then, the influence of the construction parameter uncertainty on the adjacent loaded-pile foundation is analyzed. Finally, the back analysis method is conducted based on the monitored data to evaluate how the construction process affects the pile foundation. The calculation results are compared with those of the traditional finite element method. The results indicate that in the tunneling process, the grouting pressure fluctuation greatly affects the additional bending moment of the adjacent pile foundation. Under the influence of the grouting pressure, the additional axial force and additional bending moment of the pile foundation also follow the skewed normal distribution. The back analysis results of the pile foundation are greater than those of the typical numerical method by about 60% 100%, that is using the back analysis calculation results to evaluate the pile foundation additional response can reduce the risk.

Impact of Double Shield Tunnel Construction on Adjacent Pile Foundation in Silty Fine Sand Strata

“…It was found that the settlements of pile foundation and pile perimeter soil surface were closely related to the relative position between piles and tunnels, and the pile perimeter soil settlement was mainly responsible for the pile foundation tilting (Boonyarak et al, 2014;Dias et al, 2015;Wang et al, 2018). Moreover, factors such as pile top load, ground loss, soil strength, grouting pressure, pile size, and tunnel diameter were considered as the dominant factors of the internal stress and deformation of pile foundation (Lee, 2013;Liu et al, 2014;Huang et al, 2021;Al-Omari et al, 2019;Jeon et al, 2020;Ayasrah et al, 2021;Zhang et al, 2022). Furthermore, it was investigated that the isolation pile reinforcement can strengthen the whole pile foundation, it had obviously better reinforcement effect than grout reinforcement and longeron cross bracing reinforcement (Park et al, 2015;Li et al, 2020;Lv et al, 2020;Li et al, 2021).…”