Landslide Monitoring Suitability of Sensor-Enabled Piezoelectric Geocables Based on Drawing Tests
Zhiming Liu, Guojun Cai, Jun Wang, Xuening Liu, Ruitao Tang
Abstract
Early warning of landslides is an important topic in geotechnical engineering health monitoring and disaster risk assessment. However, there is currently a lack of low-cost and distributed methods for measuring the internal deformation of slope soil over a wide area. Piezoelectric materials are widely used in various high-precision sensors because of their piezoelectric and impedance-strain effects. Hence, in this study, a sensor-enabled piezoelectric geocable (SPGC) with a polyvinylidene fluoride (PVDF) piezoelectric material was used as the core, and drawing tests of the SPGC under different normal stresses <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma _{n}$ </tex-math></inline-formula> and drawing rates <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{d}$ </tex-math></inline-formula> were conducted, including pull-out and pull-off tests. The results demonstrate that as an intelligent geosynthetic, the tensile strength of SPGC can reach 53.6 MPa, and the strain measurement range can reach 7.71%. The normalized impedance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}_{Z\,}$ </tex-math></inline-formula> –drawing displacement <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${D}_{d}$ </tex-math></inline-formula> curves corresponded well with the drawing force <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${F}_{d\,}$ </tex-math></inline-formula> –drawing displacement curves (the development of pull-out and pull-off can be detected). The force-normalized impedance curves can be described using a linear model. The real-time voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${U}_{\text {(real-time)}}$ </tex-math></inline-formula> of the pull-out and pull-off tests increased with an increase in the normal stress and drawing rate. Therefore, the proposed SPGC sensing material provides a potential new method for soil disaster location, precursor recognition, and graded early warning.