Design of reinforced cohesive soil walls accounting for wall facing contribution to stability

Abstract

Where granular materials are not easily available, local cohesive soils are increasingly employed in geosynthetic reinforced soil walls as a cheap and sustainable option. Conventional design methods do not yet account for the beneficial effect of cohesion in reducing the amount of required reinforcement. Similarly, the contribution of the face to stability is rarely accounted for, despite plenty of experimental evidence in its favour. In this paper, a semi-analytical method based on limit analysis is developed for the design of reinforced soil walls in frictional-cohesive backfills accounting for the wall contribution. A parametric analysis was conducted to evaluate the effect of soil cohesion and friction angle, facing batter, block width, location of the reaction force acting on the face, facing-backfill interface friction, facing-foundation interface friction, and reinforcement length. Dimensionless design charts providing the required amount of reinforcement for lengths recommended in design standards are provided for both uniform and linearly increasing reinforcement distributions. It emerges that accounting for the presence of cohesion and the facing element can lead to significant savings in the overall level of reinforcement, and that tension cracks can be particularly detrimental to wall stability for highly cohesive soils so they cannot be overlooked in the design.

Prediction of Reinforcement Connection Loads in Geosynthetic Reinforced Segmental Retaining Walls Using Response Surface Method

“…In this method, toe resistance was calculated using the equilibrium of the forces and bending moments of the vertical facing column. Some methods for predicting T bmax also included the influence of toe resistance [24][25][26][27]. Among them, the stiffness method proposed by Allen and Bathurst [25], which was previously known as the simplified stiffness method, has been adopted in the latest AASHTO (2020) code [28].…”