Bayesian estimation of the normal and shear stiffness for rock sockets in weak sedimentary rocks

Abstract The design of socketed foundations in weak sedimentary rocks is often governed by settlement. The shear stiffness of the rock socket sidewalls, and the normal stiffness of the rock socket base are the main parameters that affect the settlement of rock sockets at service load conditions and are needed for settlement calculation in load-transfer method or using the theory of elasticity. In this paper, in situ load test data for socketed foundations in weak rocks are collected. The shear stiffness of the rock socket sidewalls and the normal stiffness for the rock socket base are, respectively, estimated based on the measured side shear stress and shear displacement, and base contact pressure and normal displacement relationships. The parameters affecting shear and normal stiffnesses are discussed. A Bayesian approach is used to develop probabilistic models for the rock socket shear and normal stiffnesses, which are functions of both rock properties and the rock socket size.