A theoretical model for the pull-out response of geosynthetic reinforcement

Soil-reinforcement pull-out tests are essential for evaluating the strength, integrity, and effectiveness of the soil-reinforcement system. In this paper, a new pull-out test model that calculates the soil-geosynthetic reinforcement interface shear stress for highly extensible geosynthetic reinforcement is proposed. Based on a new bilinear interface shear model, the geosynthetic pull-out test results are calculated with regard to the variation of the mobilised geosynthetic tension with distance, geosynthetic pre-yield and post-yield behaviour, and the effective and extended length of the geosynthetic reinforcement. The resulting nonlinear equation for the soil-geosynthetic interface shear stress pull-out mechanism is nondimensionalised, expressed in a finite difference form, and solved numerically using the Gauss-Siedel technique. A parametric study is carried out for a range of relative stiffness values and interface shear stresses. The normalised load-displacement relationship and the variation of the pull-out force and reinforcement displacements, with distance along the reinforcement, are presented. The values calculated using the proposed model are compared with experimental pull-out test results for a needle-punched, nonwoven geotextile, polyester fibres coated with polyethylene, and nylon reinforcements.