A simplified model for evaluating the hardening behaviour of sensor-enabled geobelts during pullout tests

Geosynthetics reinforced soil structures (GRSSs) have a tendency to be large and high, resulting in high normal pressures on the geosynthetics. As one of the effective tests for investigating the geosynthetics-soil interaction, pullout tests are traditionally conducted under low normal pressures. This paper reports pullout tests on a type of sensor-enabled geobelts (SEGB) with different normal pressures (5 kPa, 100 kPa, 200 kPa and 400 kPa) applied. The self-measurement function of SEGB allows the study of the working process of SEGB in pullout tests. Moreover, a simplified theoretical model is proposed to investigate the hardening behavior of geobelts in pullout tests. Two models are incorporated in the theoretical model: a bilinear model capturing the full stress-strain curve obtained from uniaxial tensile tests and a hyperbolic model simulating the geobelt-sand interaction from direct shear tests. By means of the finite-difference method, the numerical solutions of the theoretical model are obtained. The proposed model is validated by comparing calculated and measured front pullout force-displacement curves of SEGB under different normal pressures. Further, the computation of the strain distribution of SEGB sandwiched in the sand is compared with tested data with different front pullout force levels for the aforementioned normal pressures. The numerical solutions generally agree well with the experimental results for all tested tensile force and strain ranges; therefore, the proposed simplified model is suitable for evaluating large quasi-plastic deformations of geobelts and the associated interaction with surrounding sand.