Mechanical characteristics and constitutive model of cemented tailings backfill under temperature-time effects

Abstract

The increase in original rock temperature during the deep metal mine backfill mining process significantly impacts the mechanical properties of cemented tailings backfill (CTB). Uniaxial compression experiments were conducted under various curing temperatures and times, analyzing their mechanical characteristics based on strain energy. The experimental results indicate that the mechanical properties of CTB are significantly affected by temperature. The uniaxial compressive strength (UCS) follows a quadratic trend, initially increasing and then decreasing as the curing temperature changes. At the curing temperature of 40 °C, the hydration reaction of CTB develops fully, the hydration products have strong compactness, and the energy absorbed when failure occurs is the largest. The CTB is divided into a solid framework and pore sections to develop a constitutive damage model using a combined macro and micro experimental approach. Polynomial functions represent the correlation between the damage model parameters and curing time and temperature, resulting in a unified temperature-time damage constitutive model. Using the secondary development platform in FLAC finite difference software, the damage constitutive model of the CTB was further developed and integrated into the software, enabling both its development and application. This customized model provides a more comprehensive representation of the overall deformation and failure mechanisms of the CTB during compression. The study can predict the strength of CTB under different curing conditions, and provide theoretical reference for the simulation research of filling mining in mines.