Effect of soil spatial variability on failure mechanisms and undrained capacities of strip foundations under uniaxial loading

Abstract

This paper mainly investigates the effect of soil spatial variability on failure mechanisms and capacities of strip foundations under uniaxial loading on marine clay deposits with linearly increasing undrained shear strength using random finite element analysis. The soil spatially variable feature is characterised by a non-stationary random field where the ratio of the standard deviation and mean of undrained shear strength is maintained. The effect of soil parameters, including the dimensionless soil heterogeneity index, the coefficient of variation of shear strength and the dimensionless autocorrelation distance, on the uniaxial capacities are discussed. In addition, shapes of failure envelopes for combined loading in the probabilistic analysis are compared to those shapes in deterministic analysis. Results demonstrate that the difference in shapes of failure envelopes between deterministic and probabilistic cases is minimal and can be neglected for practical purposes. Probabilistic uniaxial capacities derived in this study can be employed to scale probabilistic failure envelopes, which represent sizes of probabilistic failure envelopes. The obtained results offer insights into how soil spatial variability can be comprehensively considered in the design of an offshore shallow foundation.