Monitoring and Analysis of Pore and Earth Pressure at the Pile Surface Using Piezoresistive Silicon Pressure Transducers

Yonghong Wang,Mingyi Zhang,Jiaxiao Ma,Yongfeng Huang

doi:10.3389/fmats.2021.629370

Abstract

The piezoresistive silicon pressure transducers based on the piezoresistive effect have demonstrated their potential in the accurate monitoring of pressure. However, their usage in the pore and earth pressure monitoring at the pile surface under hydraulic jacking has not yet been explored. In this study, two self-made model piles (one is a closed-ended pile and the other is an open-ended pile) were instrumented with piezoresistive silicon earth transducers and pore pressure transducers and then driven into the soil using a hydraulic jack. A comprehensive investigation was first carried out for the structure of the model piles, the installation procedure of the transducers, and the composition of the test system. The pore and earth pressure measurements of the transducers were used for the evaluation of the distribution of the pore pressure, excess pore pressure, radial earth pressure, and radial effective earth pressure. The model test results indicate that the piezoresistive silicon pressure transducers are suitable for monitoring the pore and earth pressure at the pile surface during jacking. In addition, the pore pressure, excess pore pressure, radial earth pressure, and effective radial earth pressure along the test piles were affected by the penetration depth and the pile end form.

Highlights

With the rapid development of the economy, many high-rise and ultra high-rise buildings have been built in the cities, and the shallow foundations can no longer meet the bearing capacity and deformation requirements of these buildings
The overburden weight and horizontal pressure gradually increase, and the pore pressure at the pile surface increases linearly, and this result is consistent with the results reported by Randolph et al (1979)
A new method was developed for monitoring the pore and earth pressure at the pile surface using the piezoresistive silicon earth transducers introducing pore pressure transducers

Summary

Introduction

With the rapid development of the economy, many high-rise and ultra high-rise buildings have been built in the cities, and the shallow foundations can no longer meet the bearing capacity and deformation requirements of these buildings. The common method for pile installation is dynamic driving method and hydraulic jacking method. The hydraulic jacking method is a construction method that uses static pressure to drive precast piles into the soil (Kou et al, 2018). Compared to the dynamic driving method, the hydraulic jacking method has many advantages such as no noise, no vibration, fast construction speed, and little damage to the pile body (Wang et al, 2017a; Wang et al, 2019) and is very popular in many engineering fields. The piles are subjected to complex forces during jacking and generate excess pore pressure and radial soil pressure, adversely affecting the bearing capacity of the piles and adjacent buildings.

Methods

Results

Conclusion