Stability of steel reinforced soil walls after footing failure

Two nominal identical 4 m high steel strip reinforced soil walls varying only with respect to reinforcement layer length arrangement were constructed and instrumented in an indoor laboratory environment. A novel feature of the tests was a foundation arrangement that allowed for simulated loss of toe support. Both walls performed well at the end of construction (EOC). Predicted unfactored maximum reinforcement tensile loads at the EOC using four different load models were judged to be conservative (safe for design) based on comparison with measured loads for both walls. Reinforcement loads were observed to increase with decreasing toe support, particularly at the base of the walls. A fully developed composite soil failure mechanism propagating from the heel of the foundation bulkhead and behind the reinforcement layers was observed during excavation of the stepped base wall model. There were no visual indications of soil failure within or behind the wall with longer uniform reinforcement lengths. However, predicted EOC loads for this wall were exceeded for most layers after loss of toe support. Implications for the design, analysis and performance of steel strip reinforced soil walls with similar reinforcement arrangements constructed over initially competent soil foundations and then subject to loss of toe support are identified.