The paper focuses on the identification of the 3D failure envelope of a shallow foundation on soft soil reinforced by rig idinclusions. A nonlinear 3D finite element model is first validated agai nst literature results and novel centrifuge experi-mental data. The failure envel ope, defined in the vertical force (V), bending moment (M) and horizontal force (H) space , isthen constructed using numerical swipe tests. Analytical formulas are introduced to describe the 3D failure envelope shapeand inclination, considering the influence of the coverage area, the thickness, and the friction angle of the load transferplatform. Finally, the efficiency of a rigid inclusion foundation is highlighted by comparing its failure envelope to that ofthe same foundation without rigid inclusions. The proposed analytical failure envelope can be used by engineers to quantify the bearing capacity of rigid inclusion foundations and by researchers to develop novel macroelements submitted to complex coupled loads.