Investigation of Lateral Stress Relief Using Finite Elements and Fracture Mechanics: Case History Study of the Saxon Pit

Abstract

AbstractA published case history on the performance of a 29-m-deep excavation that occurred in stiff Oxford clay provides direct field evidence that lateral stress relief can produce shear planes. A finite-element model was developed to investigate the impact of lateral stress relief on this slope. The finite-element model utilized published site characterization data and incorporated shear-strength reductions along closed failure planes. Lateral stress relief resulted in an outward slope face movement that produced sufficient differential shear strain to develop and propagate a horizontal crack at the base of the slope. Analyses indicate excellent agreement with observed lateral and vertical slope face movements. The finite-element model suggests that the slope essentially behaved as a shear model. Recognizing the behavior of this slope, the principles of linear elastic fracture mechanics are expanded to consider closed crack propagation under shear loading conditions. Analyses indicate that a closed cra...