Seismic Stability of Retaining Wall with and Without Geogrid Inclusions in the Back Fill

Retaining structures are not inherently stable against seismic loads unless they are designed to withstand strong earthquakes. Earthquake have unfavorable effects on lateral soil pressures acting on retaining wall. Behavior of retaining structures also depends on properties of backfill and sub-grade soil. During earthquake, the reinforced soil-wall system may either move together with the ground or move relatively respect to the ground. These two conditions are referred to as absolute motion and relative motion, respectively. This paper presents an analytical method of nonlinear dynamic behavior retaining wall using finite element method, when subjected to seismic loads. The primary objective of the study is to develop a model to determine the response of retaining wall under seismic load. The Drucker–Prager material approach is used for elasto-plastic soil behavior. Sub-grade soil is modeled as 3D element by Drucker–Prager method. In this study, dynamic behavior of retaining wall for different backfill soil materials with geogrid at different levels are studied. The geogrid layer inclusions in backfill are expected to reduce the active earth pressure subsequently enhancing the stability. Finite element model of retaining wall of height 7 m and 15 m length modeled in ANSYS software and dynamic response spectrum analysis is carried out. The properties of the materials, dynamic seismic loads, site effects, water pressure are prime factors considered to evaluate response. The results with and without geogrid are compared.