Landslide Monitoring Suitability of Sensor-Enabled Piezoelectric Geocables Based on Drawing Tests

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.