Predicting the uniaxial capacity of plate anchors in spatially variable clay using metamodels

This paper investigates the effect of spatial variability in undrained shear strength on the uniaxial capacity of a deeply embedded plate anchor. The study was undertaken using the random field finite element method, and the results show that the ultimate uniaxial capacity is significantly influenced by strength heterogeneity, which is influenced by the different mobilised failure mechanisms and leads to a widely distributed probability of failure. Interpretation of the results also shows that it is possible to relate the statistical distribution of an operative undrained shear strength to the probability of failure of the plate, using close to constant uniaxial capacity factors. These findings simplify the assessment of plate capacity to the determination of the operative undrained shear strength, without needing to resort to computationally expensive finite element analyses. Additionally, the operative undrained shear strength obtained from random field modelling can be accurately emulated by metamodelling, which can then be used to correlate the input variables to the statistical distribution of the operative undrained shear strength. Through reference to a specific foundation geometry and set of soil variability parameters, this paper illustrates the potential of a simple and computationally cost-effective analytical procedure which, by combining random field finite element analyses and metamodels, relates site-specific field input variables to the probability of failure of a deeply embedded plate anchor in a spatially variable clay.