On the numerical issues of the NorSand model in the simulation of undrained behavior of granular soils

ABSTRACT: The NorSand model is one of the most used soil models to simulate the undrained and drained response of granular materials. The model requires the following parameters: two elastic material properties, three to four parameters to define the critical state in e-p and q-p space, two parameters to define the image stress ratio and limiting dilatancy, and two hardening parameters. These few material properties and a straightforward procedure to determine them are the main reasons for the considerable growth of the NorSand application in the simulation of the stress-strain behavior of granular materials. However, the material properties are obtained mainly based on drained test results conducted on dense samples. Therefore, the model uses some assumptions and mathematical techniques to modify its response to simulate the undrained behavior of soil states looser than the critical state. This paper explains how the NorSand model employs this mathematical technique and discusses the effectiveness of this approach.