Assessing the Effects of Induced Tensile Stress on Geotechnical Behavior of Foundations Using Fracture-Based Continuum Modeling

This paper assesses the contributions of induced tensile stress in the behavior of foundations in order to make a case that tensile stress induced by foundation loading needs to be considered in geotechnical analysis for foundations that apply high loading and are sited on sloping ground, subsurface materials with complex geometry, or other conditions that do not conform to the assumption of shear-dominant failure that is the basis for foundation analysis used in current practice. The assessment uses numerical simulations using fracture-based continuum modeling (FBCM), which models mechanical damage of subsurface materials in terms of the initiation and propagation of shear and tensile failure surfaces (fractures). FBCM models fractures explicitly in a continuum framework using fracture transformation matrices to encapsulate, thus automating the creation and use of fracture geometry. The assessment shows that tensile and shear damage mechanisms contribute to behavior of foundations on sloping ground, with the tensile mechanism increasing as setback from the slope crest decreases. For a large setback, failure is shear-dominated but tensile mechanisms occur at the ultimate state. In contrast, tensile mechanisms dominate the failure of foundations at a small setback. Additionally, the paper provides verification of FBCM for foundation analysis by comparing model calculations against published results.