Numerical integration of the Glasgow Coupled Model (GCM)

This paper presents the derivation of incremental constitutive relations Glasgow Coupled Model (GCM), an established elasto-plastic model for unsaturated soils intended to represent their mechanical and water retention behaviour. The set equations derived defines initial value problem (IVP) that needs be solved at each integration step once (or previous) state theincrements suction strain are known. To solve this IVP effectively, a small reformulation GCM (not involving any modification model, but simply presenting it differently) has been adopted withthe aim facilitate development robust algorithm capable identify unambiguously correct response activated by given stress path (i.e. elastic, yielding, yielding or simultaneous yielding). Subsequent description algorithm, explicit substepping scheme with automatic error control able integrate possible response, including saturated conditions. numerical capabilities in terms accuracy efficiency then demonstrated context performance maps proposed originally soil models.