The bearing capacity of footings on granular soils. II: Experimental evidence

Scale effects, especially stress-level effects, cause considerable confusion in the calculation of bearing capacity on granular soils. A companion paper describes a new method of calculation that explicitly allows for the variation of sec φ with mean effective stress p. This approach is validated here for the case of model circular footings on dense beds of silica sand and silica silt. The models were tested at 1g with surcharge to explore the N_q behaviour, and in a centrifuge to determine self-weight effects for N_γ. It is shown that triaxial φ values expressed as a function of the logarithm of p can be used to predict model bearing capacities within a deviation in φ of 2°.