Wireless tilt sensor based monitoring for tunnel longitudinal Settlement: Development and application

Abstract

The monitoring of longitudinal settlement of tunnel linings plays a great role in the preventive maintenance due to the significant effect of settlement on degradation of the serviceability of tunnel. This paper introduces a novel tilt sensor based vertical deformation monitoring system (VDMS) for the longitudinal settlement of tunnel linings. The VDMS utilizes a Micro-Electronic-Mechanical-System based wireless tilt sensor that is embedded in a rigid tube, making it easy to assemble and disassemble. The joint design between successive tubes is well-designed to ensure accurate monitoring of the vertical deformation of linear structures. A calibration test is carried out, and a compensation algorithm is proposed to reduce systematic error. The VDMS achieves a purely random relative closure error of about 2.22%. The monitoring accuracy is compared to the robotic total station, which is more expensive and only used for emergence monitoring. The mean discrepancy between the VDMS and the total station is limited to 6.15%, demonstrating the high accuracy of the VDMS. Overall, the VDMS offers high precision, ease of assembly and disassembly, and friendly installation, making it a valuable tool in preventive maintenance for tunnel serviceability.