Abstract
The application of stress-deformation analyses on tailings storage facilities (TSF) is becoming a standard practice usually conducted with a myriad of goals, including assessing the physical stability and expected deformation for static and dynamic loads, setting threshold values for key monitoring variables, and evaluating dam performance during construction. Additionally, these analyses can be used to explain displacement patterns, such as settlement or surface cracking, thereby enhancing understanding of the facility’s behavior. This paper aims to demonstrate the effectiveness of deformation analysis in explaining the development of surface cracks and deformation patterns observed on an upstream raised TSF during construction and operation.
The studied TSF has a maximum height of 35 m from toe to crest. It was constructed in four stages, beginning with a 20 m-high starter dam, followed by three 5-m-upstream raises. Shortly after the construction of the first raise was completed, surface cracking was observed at the crest of the dam and downstream slope. After the cracks were detected, additional instrumentation was installed to monitor displacements and crack progression within the TSF during the operation and construction of the following three raises.
To provide confirmation of the conceptual explanation for the observed cracking and deformation pattern, a numerical simulation of the different construction stages of the TSF was completed using a two-dimensional finite element software. Initially, a simplified model with a reduced number of variables to provide a qualitative understanding of the physical phenomenon was developed. Later, a detailed analysis was conducted with the aim of reproducing the recorded displacements quantitatively. The constitutive models were calibrated based on available field and laboratory information. Sensitivities were carried out on the geotechnical parameters to evaluate the impacts on the response of the model and identifying the critical ones influencing the cracking and the ongoing displacement .
The paper presents the capacity of the stress-deformation analyses in explaining the performance of the tailings dams during operation and raise but also to provide understanding of events involving multiple elements and complex interactions. The findings of this study are discussed from both qualitative and quantitative perspectives.
Authors:
Ignacio A. Cueto (Presenter) | SRK Consulting, Canada
Osvaldo N. Ledesma | SRK Consulting, Canada
Raul Norambuena Mardones | SRK Consulting, Canada
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