An undrained expansion solution of cylindrical cavity in SANICLAY for K0-consolidated clays

Abstract

This paper proposes a rigorous undrained solution for cylindrical cavity expansion problems in K0-consolidated clays, adopting a simple non-associated and anisotropic model, SANICLAY. The cavity expansion theory is well extended to consider non-associativity, K0-consolidation and stress-induced anisotropy with combined rotational and distortional hardening of yield surface and plastic potential in the multiaxial stress space. The developed solution can be recovered for validation against the modified Cam-clay (MCC) solution by simply setting model constants, avoiding non-associativity and anisotropy. The source code is provided to facilitate the use for extensions. After investigating the effects of overconsolidation ratio on the cavity pressure curves, stress distributions, evolutions of anisotropic parameters and stress paths, the variations with three-dimensional (3D) evolutions of yield surface and plastic potential during undrained cavity expansion are shown for various K0-consolidated clays. A parametric study on the model constants is presented to depict the influences on the stress distributions and paths, critical state surfaces and Lode's angles at failure. The proposed solution also provides a general framework for formulating equations for undrained expansion of cylindrical cavities under an initial cross anisotropic condition using sophisticated anisotropic soil models. It serves as a precise benchmark for extensions of analytical solutions, numerical simulations of cavity expansion, and back-calculations of geotechnical problems.

Keywords

• Undrained cavity expansion
• SANICLAY
• K0-consolidation
• Anisotropy