An innovative liquid metal-based pressure sensor with its application in geotechnical engineering

Abstract

In this paper, a monitoring system containing a novel liquid metal-based pressure sensor and remote interactive monitoring devices are fabricated to monitor stress in geotechnical engineering. The pressure sensor with the dimension of 34 mm × 34 mm is designed and manufactured, which is mainly composed of 40CrMoV alloy steel shell, polydimethylsiloxane (PDMS) and liquid metal gallium indium alloy (EGaIn). It has the characteristics of high stability, can greatly improve the measurement range of the pressure sensor (0 to 20 MPa), and its resistance variation is from 0 mΩ to 800 mΩ. In addition, the linear regression analysis is carried out to verify the linear relationship between the resistance of sensor and the applied pressure. It is found that the performance of the pressure sensor is fine through experiments with three different loading rates and fatigue experiments. The remote interactive monitoring device can be suitable for the field monitoring environment, which is composed of monitoring stations (MS), remote communication base stations (RCBS) and indoor working platform. Finally, the monitoring system is successfully applied to the field measurements in geotechnical engineering, and the field monitoring data are in good agreement with the numerical results.