Undrained Behaviour Overview
RS2 allows you to model both drained and undrained behaviours. Materials are in drained behaviours by default. Three topics are included for this subject.
Undrained Behaviour of Soil
The undrained behaviour can be modelled in different approaches in RS2. The inputted strength and stiffness parameters, and undrained settings (by material or by stage) are considered. The calculations by RS2 to reflect undrained behaviour might be different for different approaches. See the Undrained Behaviour of Soil topic for theories and details on each approach.
Drained / Undrained Settings
The drained / undrained setting can be specified either by material or by stage if consolidation analysis is enabled. See the Drained / Undrained Settings topic for more details about their differences and applications.
Effective Stresses Calculation in Undrained Materials
Calculations will be applied to account for undrained behaviours. This topic uses the method including an undrained effective stress analysis and effective strength parameters. See the Effective Stress Calculation in Undrained Materials theory manual for more information.
However, if the analysis is coupled consolidation, then a global matrix will be involved instead. See the Undrained Behaviour of Soil – Undrained Calculations section for more details.
For additional information about undrained behaviour, see the following resources:
RS2 Stress Verifications – #32 Undrained behaviour modelling in consolidation analysis of strip footing
RS2 Stress Verifications – #15 and #23
RS2 Consolidation Verifications – #4 and #5
- Note that the consolidation option is coupled (Biot) for RS2 Consolidation Verifications