The analysis of connected back to back mechanically stabilised earth walls.

Abstract

Back to back mechanically stabilised earth walls (MSEW’s) are designed independently as there is a lack of design guidance in the British Standard - Code of practice for strengthened/reinforced soils and other fills (BS8006-1:2010) for their analysis and design. Designers are sometimes tempted to have continuous reinforcement from each face of the back to back MSEW’s to save time and money especially when narrow back to back MSEW’s cause an overlap of reinforcement from each wall face. Unfortunately, the design guidance available is few and far between with vague recommendations presented by various authors and organisations. This dissertation focuses mainly on the forces generated in the reinforcement of the MSEW’s. A case study of an existing back to back MSEW with continuous reinforcement between the walls was first carried out using BS8006-1:2010 and finite element methods (FEM). The FEM analysis was carried out using the finite element modelling software package Plaxis 2D. Thereafter, a study using FEM was carried out to investigate the effects on the forces generated in the reinforcements for various types of geometries. The different geometries varied by having back to back MSEW’s with independent reinforcement, continuous reinforcement, and overlapping reinforcement. The forces generated in each configuration was then compared to forces that would have been calculated had the MSEW’s been designed using BS8006-1:2010. Conclusions and recommendations are then provided which would assist a designer wanting to have continuous reinforcement in a back to back MSEW.