New Model for Predicting the Bearing Capacity of Large Strip Foundations on Soil under Combined Loading

The bearing capacity of large strip foundations under combined loading is an important issue in geotechnical engineering, which is related to the design and stability analysis of foundations such as gravity dams, retaining walls, and ground anchorages of bridges. Herein, a new model for predicting the bearing capacity of large strip foundations under combined loading was proposed. First, a series of numerical simulation analyses of a large strip foundation resting on the surface of the soil were conducted to investigate the shape of the failure envelope in the V-M-H (vertical load, overturning moment, and horizontal load) loading space, and an improved form of failure equation was proposed. Second, the main factors influencing V-max (the vertical ultimate bearing capacity) and the shape of the failure envelope were determined. Last, an applicable empirical equation of the failure envelope in the V-M-H loading space was presented. The results show that the deflection angle of the ellipse (theta), which is considered as a certain constant by previous studies, varies with the vertical load (V); the width of the foundation (B), the depth of the foundation (D), the cohesion of the soil (c), and the internal friction angle of the soil (phi) are the main factors influencing V-max and the shape of the failure envelope; only parameters B, D, c, phi, and gamma are needed to determine, in a unique way, the empirical equation of the failure envelope in the V-M-H loading space. The proposed model provides a convenient means of calculating the bearing capacity of large strip foundations on soil under combined loading. (C) 2022 American Society of Civil Engineers.