Evaluation of mechanical and electrical properties of a new sensor-enabled piezoelectric geocable for landslide monitoring

Abstract

The embankment and slope are prone to internal deformation and progressive failure under the coupling action of water, heat and force. Therefore, scholars have attempted to reflect the coupled deformation of soil through deformation measurements of geosynthetics. However, all the current measurement methods are non-distributed methods, and there are problems such as a significant installation effect, small strain measurement range, and low survival rate. In view of these issues, this study used a sensor-enabled piezoelectric geocable (SPGC) based on the piezoelectric effect and impedance-strain effect. The laboratory in-isolation and in-soil tests were carried out, and the signals of the strain–stress-impedance-voltage of SPGC under different failure modes were tested. The results showed that the tensile strength and elongation at break of the SPGC reached 53.6 MPa and 45.46%, respectively. During the tensile failure process of the SPGC, the strain–stress curve was divided into five stages, the strain-normalized impedance curve was divided into three stages, the strain-voltage curve was divided into two stages, and there were three characteristic points that could be classified as level 3 warnings. Empirical calculation formulas for the strain-normalized impedance was established, and the strain of the SPGC within 10% could be qualitatively described and quantitatively calculated by monitoring the normalized impedance. During the clay drawing failure process of the SPGC, the normalized impedance increased and the voltage decreased with the increase of pulling displacement. During the clay shear failure process of the SPGC, a bilinear model could be used to describe the correlation between shear displacement and normalized impedance. The voltage increased with the increase of shear displacement. The research findings suggest that SPGC can realize soil disaster location, precursor identification, and graded early warning, and is expected to provide a distributed, real-time, and refined measurement method for the entire life cycle of geotechnical engineering operation and maintenance monitoring.