Model Studies on Footing Beam Resting on Geogrid Reinforced Soil Bed

Abstract

Geogrid reinforcement below foundation (resting on layered soil conditions having less bearing capacity) to support footing has considerable effect on shear, settlement and cost reducing alternative to conventional method of support. Therefore, in the present paper, a 2D finite element soil- foundation interaction modeling of a square footing has been carried out to investigate the effect of types of geogrid on sttlement, contact presseure and elastic strain.  Performance level of geogrids made from three different types of polymer polypropylene, polyester and non-polymer (PP, PET and NP) have been analysed. Foundation system consists of a square footing beam resting on layered soil conditions (upper compacted and lower loose). Geogrid reinforcement is provided between upper dense soil and lower loose soil and has been assumed to have finite bending stress and, therefore, idealized as a beam. Both soil layers are also assumed to have finite bending stresses. Analysis is carried out by using a computer software program ANSYS with a two dimensional linear 8-noded isoparametric element. The result of analysis is compared with both the systems (foundation system with geogrid reinforcement & without geogrid reinforcement) and optimum thickness and optimum depth of placement of geogrid reinforcement have been found. It is found that use of geogrid and the types of geogrid affect the behavior of the foundation system significantly.

Keywords: Footing beam; Geogrids; Settlement; Contact Pressure.