Interface pullout resistance of polymeric strips embedded in marginal tropical soils

This paper presents an experimental and analytical evaluation of factors affecting the interface pullout resistance of polymeric strips embedded in marginal soils, with a particular interest in supporting the partial replacement of natural sands by intensely weathered tropical soils in reinforced soil structures, which have often been considered marginal fills in design guidelines. Large-scale pullout tests were conducted to evaluate the soil-geosynthetic interface pullout resistance, which also provided quantitative insight into the local increases in vertical stresses acting on the reinforcements due to pullout. Based on the experiments, analytical models were developed and calibrated to establish the relationship between confinement and soil-geosynthetic interface pullout resistance. The relationship between actual and initial stresses could then be represented in terms of a linear model in which the angular coefficient corresponds to the ratio between the apparent and actual friction coefficients (f*/f). This analytical relationship was found to represent a useful design tool since it directly correlates with soil geotechnical properties. The use of lateritic soils to partially replace coarse-grained soils in reinforced soil structures was found to be feasible for mixtures involving up to 25% of lateritic soils, with higher fractions affecting the interface resistance significantly.