A Finite Element Study of Beam on Reinforced Granular Beds with Sand Drains

ABSTRACT: This paper presents the settlement analysis of a beam resting on geosynthetic reinforced granular fill-soft soil system. Each subsystem of the reinforced fill-soil system is idealized by elastic membrane, Pasternak shear layer, Winkler springs and dashpots, as applicable. The suggested model incorporates various aspects of the behavior of the geosynthetic-reinforced granular fill-soft soil system such as horizontal stress induced in the granular fill, the compressibility of the granular fill, and the time-dependent behavior of the subgrade. The differential equations governing the settlement response of the beam resting on two layered reinforced foundation soil has been formulated by incorporating deformation compatibility conditions. The numerical solutions are obtained using Finite Element Method and results are presented in non-dimensional form. The parametric studies are carried out to enumerate the effects of parameters on the settlement response of the system. Results indicate that over a large number of various parameters under large deformation the proposed model evaluate the settlement of the system and horizontal displacement of membrane with reasonable accuracy. It is observed that compressibility, shear modulus and thickness of granular fill, pre-stressing and tension modulus of reinforcement have appreciable influence on the settlement of the system and horizontal displacement of membrane. It is observed that the horizontal displacement of the geosynthetic membrane is negligible as compared to that of the vertical settlement. The model is also analyzed for the case of a sand drain in the soft soil which indicated that the elapsed time and the radius of the sand drain significantly affects the settlement response of the system.