Civil Engineering Departmental Seminar - Bearing capacity of soils - new insights from advanced finite element analysis

Bearing capacity of soils - new insights from advanced finite element analysis

The bearing capacity of soils is critical for the design and analysis of foundations. The classical solutions derived from the method of characteristics and bound theories are based on the rigid plasticity and associated flow rule, which may not be realistic for natural soils. The undrained shear strength of soft clays exhibits strain-softening, anisotropic, and rate-dependent behavior in the lab tests, which creates complexity to choose appropriate strength parameters in the conventional design process. The behavior of sand is strongly nonlinear and depends on the stress level and void ratio. In addition, the stress-strain characteristics of soils are non-associative and path-dependent, which also affects the bearing capacity of soils. This seminar investigates two classical stability problems (i.e. deeply embedded pile/pipe section, and rigid strip footing) using finite element analysis and advanced soil models, and demonstrates the effects of stain-softening, strength anisotropy, and loading rate on the undrained bearing capacity of clay, as well as the effects of void ratio and footing size on the drained bearing capacity of sand. These findings have strong practical implications to predict the bearing capacity of foundations and interpret insitu tests.