In Situ State of Tailing Silts Using a Numerical Model of Piezocone Penetration Test Developed by Norsand Model

Abstract

Tailings are the reservoirs containing a high proportion of saturated silts that may be extremely difficult to sample in their undisturbed condition. This is mostly due to the fabric disturbance and densification that can alter soil behavior. Meanwhile, assessing the in situ state of deposits is indispensable to stability analyses. A useful parameter defining states of soils is state parameter (Ψ), usually determined using the results of the cone penetration test. In this study, several series of numerical analyses of the piezocone penetration test (CPTu) were carried out for saturated tailing silts to evaluate the resistance against penetration for different soil properties and initial states. The numerical simulation adopted the Norsand model as an appropriate constitutive law to capture silt behavior. Analyses indicated that the familiar methods for determining the initial state of soils from CPTu results fail to precisely estimate the initial state parameter (Ψ0) in saturated tailing silts. Therefore, the numerical model was applied to tailing silts to propose relationships using cone penetration resistance to predict the initial state parameter. In addition, the numerical model procedure and the proposed relationships are validated with available numerical and field -piezocone soundings measurements.