Deformation analysis of deep foundation pit excavation in China under time–space effect

Qingwei Zhang

doi:10.1680/jgere.20.00009

Abstract

The excavation of a deep foundation pit often causes deformation, so it is of great value to analyse the issue. In this study, the space–time effect of foundation pit deformation was introduced, and then the deformation of a deep foundation pit in Anyang, China, was monitored and analysed. The results showed that the displacement of the foundation pit enclosure structure increased gradually with the progress of the project, and there was a gap between the displacement values of different parts. The maximum displacement at the middle point of the long side was 13 mm, and that of the corner was only 5 mm. The vertical displacement of the surrounding buildings increased with the progress of the project, and the displacement value near the corner of the foundation pit was relatively small. The closer the surrounding pipelines were to the middle point of the foundation pit, the larger the displacement value was, and the displacement value also increased with the progress of the project. The results of this study show that the deformation of a deep foundation pit accords with the time–space effect, which provides some references for the deformation analysis of deep foundation pit engineering.

Highlights

With the rapid development of society, the process of urban construction has sped up (Hu, 2017), and the number of buildings on the ground are increasing and the land resources are declining
The deformation of a deep foundation pit in Anyang City, China was monitored and analysed. It was found from the monitoring results of the horizontal displacement of the enclosure structure that the displacement value of the enclosure structure gradually increased with the progress of the project, but the displacement value had a large difference between the long side and corner of the enclosure structure
The maximum displacement value at the middle point of the long side was about 13 mm, while that at the corner was only 5 mm, which conformed to the time–space effect

Summary

Introduction

With the rapid development of society, the process of urban construction has sped up (Hu, 2017), and the number of buildings on the ground are increasing and the land resources are declining. Zhang et al (2015d) monitored a foundation pit project in Shanghai, China and found that the settlement value of adjacent buildings gradually increased with the progress of the project; the structural settlement was large due to the long-time excavation of the fourth layer of soil and the removal of the support would slightly increase the settlement value of the building. Taking a deep foundation pit in Anyang City, China as an example, this study performed a simple analysis of the deformation of a foundation pit under the effect of time and space, in order to provide some scientific references for the smooth progress of the project. With the progress of the project, the horizontal displacement increased first and decreased, and the displacement value increased with

21 Excavation completion of the first layer

Discussion

Conclusion