DIC assessment of foundation soil response for different reinforcement between base and soft subgrade layer – Physical modeling

Abstract

This paper presents insights from small-scale model tests on statically loaded strip footing on dense base sand supported by a single reinforcement layer. The selected reinforcement includes various lengths of wire mesh and a non-woven geotextile placed on soft subgrade sand. The influence of these inclusions on base and subgrade response (deformations and failure mechanism) is evaluated from the displacement pattern obtained by the digital image correlation (DIC) technique. The benefits of the reinforcement and geotextile were assessed by comparing the results obtained for the improved and unreinforced soil model. Additionally, the confining effect of the reinforcement was experimentally analyzed by comparing the sand displacements around the wire mesh reinforcement with different aperture geometry and geotextile without apertures. These systematically selected reinforcement geometries enabled the investigation of the aperture size influence on base and subgrade behavior during surcharge loading. Results confirm the contribution of reinforcement inclusions to the improved behavior of base and subgrade layers compared to the unreinforced soil. The test results with different reinforcement confirm the influence of the aperture geometry on the model response during the surcharge load application. Compared to large apertures, enhanced confining and membrane actions were obtained for reinforcement with relatively small apertures.