Seismic stability of reinforced soil wall considering oblique pull – coherent gravity method

Conventional analysis and design of reinforced soil walls assume that the reinforcement is subjected to axial pullout. However, kinematics of reinforced soil structures demonstrates that the rein-forcement is subjected to oblique pull. Mobilization of transverse force due to oblique pull depends on the stiffness of backfill and the interface friction angle. Few studies demonstrated an improvement in the fac-tor of safety against pullout by considering the mobilized transverse force for static and seismic loads. In the present study the seismic stability of a reinforced soil wall is analyzed based on the coherent gravity failure mechanism. A bi-linear failure surface is considered and the tensile force in the reinforcement due to static and dynamic earth pressures quantified. Transverse force mobilized due to oblique displacement of failure wedge is computed along with the improved pullout resistance of sheet reinforcement. Variations of modified factor of safety against pullout due to horizontal seismic coefficient, backfill stiffness and oblique displacement are presented. Current study brings out the conservatism of existing seismic de-sign and analysis methods based on consideration of axial pullout of reinforcement.