Numerical analyses of the failure of geosynthetic-reinforced soil beneath shallow foundations subjected to inclined load.

The use of geo-reinforcements under shallow foundations is aimed to increase the soil mechanical properties and, consequently, to improve the footing load carrying capacity reducing the associated settlements. Simplified approaches generally rely on corrective factors, allowing the analysis of reinforced foundation starting from the knowledge of the performance of the unreinforced one. A critical aspect refers to the applied load: for footings subjected to inclined loads, it is not possible to assess the bearing capacity and the displacements by using simplified methods referred to vertical loading conditions. The paper reports the results of numerical FEM analyses, aimed to investigate the limit conditions for a shallow strip footing subjected to inclined load and to highlight how the failure envelope (in the plane of vertical V and horizontal H load components) of the reinforced foundation modifies (in size and shape) in comparison with that of the unreinforced one. The use of the failure envelope approach, instead of the usual bearing capacity corrective factors, allows a more rational analysis of the interaction phenomena occurring in the reinforced soil. The numerical analyses enable to consider different cases as to the reinforcement arrangements and types.