Deformation behaviour of geobelt in weathered rock material-tire shred lightweight soil under pullout condition

The weathered rock material-tire shred lightweight soil has advantages such as low density and high permeability, which could significantly reduce the structure deformations. However, the deformations of geosynthetics in this lightweight soil are still needed to be investigated. This paper presents a series of pullout tests on an innovative geosynthetics sensor-enabled geobelts (SEGB). Different mass ratios of tire shreds (10%, 15% and 30%) and normal pressures (30 kPa, 50 kPa and 100 kPa) are also considered. With the reinforcement and self-measurement of SEGB, the distributed measurement on strain of SEGB could be realized via measurement of electric resistances. Based on the uniaxial tensile tests and direct shear tests, a bilinear model capturing the full stress-strain curves of SEGB and a hyperbolic model evaluating the geobelt-soil responses are developed, respectively. The two models are employed in the derivation of the load transfer equation of pullout process. Solved by finite difference method, the load transfer equation gives numerical results about the distributions of tensile force, strain, displacement and interfacial shear stress along the geobelt. The test results validate the numerical results, including the constitutive models and the solving method. There exists an optimal mass ratio of tire shreds for the best frictional characteristics of geobelt-soil interfaces. The values of tensile force, strain, displacement and interfacial shear stress reach the peak values at the front end of geobelts, then decrease along the geobelts and gradually remain stable. Under high normal pressures, the geobelts exhibit visco-plasticity with larger strain levels and smaller displacements. The interfacial shear stress shows a more even distribution under a low normal pressure.