Calibration of Constitutive Models for Tailings Material with OpenSees

A single constitutive model able to capture the numerous aspects affecting the behavior of different soil types under different initial, boundary, and load conditions, and therefore different deformations levels, does not exist. However, several constitutive models can simulate the behavior of certain materials under given conditions. Therefore, the first fundamental task aimed at obtaining reliable results by numerical methods is to choose the most suitable soil constitutive model. In this study, different constitutive models are calibrated in order to reproduce the behavior under cyclic loads of mining waste materials, better known as ‘tailings’. These materials exhibit a typical behavior of contractive non-cohesive intermediate soils which can be reliably simulated using a coupled non-linear approach. For this purpose, three models were considered: Manzari-Dafalias SANISAND [1], PM4SAND [2], and Pressure Dependent Multi Yield 02 (PDMY02) [3, 4]. Each model has several parameters that must be calibrated to obtain reliable results in reproducing the soil behavior for the problem to be analyzed. Some of these parameters might not be physically based or cannot be determined through standard procedures. This paper presents the techniques and procedures used to calibrate the aforementioned constitutive models. Specifically, the behavior of materials collected at a tailings storage facility located in southern Tuscany (Italy), subjected to cyclic triaxial tests, will be numerically simulated using the OpenSees software.