Site-Response Analysis of Geotextile-Reinforced Toyoura Sand

The response of an equivalent 1 m thick layer of dry, medium dense Toyoura sand reinforced with geotextile fibres was measured in a laminar box under 27 one-dimensional (1D) horizontal harmonic shakings applied to the base of the laminar box. Laser displacement transducers and accelerometers were used to measure the lateral deformation of the box and calculate the shear stress in the soil, respectively. Two distinct site-response analysis techniques were employed to simulate the experiments, including (a) nonlinear analyses and (b) simplified equivalent linear analyses. Differential equations of the site-response analysis are formulated and solved using the finite difference method (FDM). Shear stiffness degradation curves for the reinforced and unreinforced models were indirectly rendered from the laminar box models on the shaking table. These data were fitted with a universal hyperbolic degradation model and integrated into a nonlinear site-response analysis scheme to simulate the horizontal displacement profile of different laminar box models. Results proved that precise estimation could be made as far as there is good knowledge about the shear stiffness modulus degradation model and the level of the shear strain occurred within the soil model. Moreover, Geotextile fibre reinforcement showed both experimentally and analytically to have reduction influences on the horizontal deformation of the reinforced sand models.