Mathematical modeling and analysis of in-situ strength development in cemented paste backfill structure

Liang Cui, Mamadou Fall

In the proceedings of: GeoEdmonton 2018: 71st Canadian Geotechnical Conference; 13th joint with IAH-CNC

Session: Mining Geotechnics and Hydrogeology III

ABSTRACT: Cemented paste backfill (CPB) structures are complex underground geomechanical systems. After placement of the fresh CPB into stope (mined-out underground space), a strongly nonlinear and time-dependent variation of material properties and behaviors takes place in CPB mass due the coupled thermo-hydro-mechanical-chemical (THMC) processes. Moreover, the field curing conditions (e.g., CPB-rockmass interaction, stope conditions (geometry, inclination angle, and barricade drainage), and the in-situ temperature) can be significantly different from the laboratory conditions, which may further affect the multiphysics processes and thus the development of CPB strength. Consequently, the actual strength development of CPB in the field may be significantly different from that in the laboratory. Therefore, to accurately and reliably predict the in-situ CPB strength, the effect of the coupled THMC processes must be fully considered and quantitatively assessed. In this study, a coupled multiphysics model for CPB strength is developed and has been successfully validated against the measured data. Then, the validated model is applied to study the changes in the strength of CPB structure under various field conditions (e.g., backfilling strategy, inclination angle of stope, and filling rate). The obtained results provide better insight into the process of the strength increase and spatial distribution in CPB structures as well as contribute to more cost-effective engineering designs of CPB structures.

Please include this code when submitting a data update: GEO2018_149

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