Behaviour of Geosynthetic Reinforced Soil (GRS) Wall as a Bridge Abutment Using Numerical Analysis

Abstract

Reinforced soil walls (RSW) are the cost effective soil retaining walls and are gaining popularity now a days. The factors influencing the use of these walls includes economical, simple and fast construction techniques, better seismic performance. The use of GRS walls as bridge abutment is an alternative to the conventional use of deep foundation systems to support the bridge abutment. These effectively reduce the differential settlement arising between the bridge abutment and the approach roadway and this is called as the ‘bump at the bridge problem’. To check the stability of these structures the Limit equilibrium methods are commonly used because of its simplicity. Mostly these methods are empirical in nature and they don’t consider actual soil reinforcement interaction. Finite element method (FEM) and limit analysis (LA) methods are effective in finding the stability of a structure. The present study, discusses the numerical analysis of a full scale reinforced soil wall using commercially available software’s PLAXIS 2D and LimitState:GEO. The deformation and safety analysis has been carried out for the RSW by considering a surcharge on it which can be simulated as a bridge abutment. The effect of different parameters such as unit weight and the angle of internal friction of the; length of the reinforcement; the number of reinforcement; and interface coefficient between backfill and reinforcement on the performance of the GRS wall has been studied. The surcharge is applied on the wall with a certain setback distance (D) in terms of the height of the wall (H). From the analysis it is found that the friction angle of the backfill has the maximum contribution in increasing the factor of safety (FOS) of the wall. Two different case studies have been taken for the analysis and the results obtained from numerical study are in comparison with that of the measured values.