Behavior of nonwoven-geotextile-reinforced sand and mobilization of reinforcement strain under triaxial compression

摘要

Laboratory triaxial compression tests were conducted to investigate the stress–strain–nvolumetric responses of geotextile-reinforced sand and the mobilization and distribution ofnreinforcement strain/loads and soil–geotextile interface shear stress within reinforced soil.nGeotextile-reinforced sand specimens were tested while varying the confining pressures and numbernof geotextile reinforcement layers. A digital image-processing technique was applied to determinenresidual tensile strain of the reinforcements after tests and to estimate reinforcement tensile loads.nExperimental results indicate that the geotextile reinforcement enhanced peak shear strength andnaxial strain at failure, and reduced loss of post-peak shear strength. The reinforced specimen hadnhigher shear strength when compared with that of unreinforced soil after deforming by 1–3% ofnaxial strain, which indicates that the geotextile requires a sufficient deformation to mobilize itsntensile force to improve the shear strength of reinforced soil. For each reinforcement layer,nmobilized tensile strain peaked at the center of the reinforcement and decreased along the radialndirection, while the interface shear stress was zero at the center and peaked at a distance of 0.5–n07 reinforcement radius from the center. The mobilized tensile strain of reinforcement increases asnconfining pressure and number of reinforcement layers increase. This work also demonstrates thatnthe strength difference between reinforced and unreinforced soil was strongly correlated with thensum of maximum mobilized tensile forces of all reinforcement layers, indicating that mobilizedntensile force of reinforcements directly improved the shear strength of reinforced soil. Last, annumber of analytical models to predict peak shear strength of reinforced soil are verifiednexperimentally. This verification demonstrates that mobilized tensile force rather than ultimatentensile strength can be used in analytical models.