Mechanical properties and energy evolution of cemented tailings backfill at different curing temperatures

The mechanical properties of cement-based tailings cemented backfill can be significantly influenced by the curing temperature. Uniaxial compression tests were conducted in the laboratory on backfill samples cured at different temperatures to investigate the influence of curing temperature on the stress-strain curve and mechanical properties of the backfill. Additionally,the energy evolution law at each stage of backfill deformation and failure was studied. The results demonstrate that as the curing temperature increases from 20℃ to 50℃,the peak stress,initial crack stress,and elastic modulus of the backfill exhibit a first-increasing and then decreasing trend,reaching a maximum value at 30℃,indicating the existence of a critical value. Moreover,the total strain energy and elastic strain energy of the backfill at the peak stress point also follow a similar trend,with dissipated energy and total strain energy exhibiting a nonlinear increasing relationship with axial strain. Notably,in the initial compaction,linear elastic deformation,and yield failure stages,the energy is mainly stored in the form of elastic energy inside the backfill,while it is primarily dissipated in the post-peak deformation and failure stage. The curing temperature can affect the energy index level. Microscopic testing results indicate that the free water evaporation effect of the backfill in a high-temperature curing environment leads to a more apparent internal void structure of the backfill,which negatively affects its mechanical performance.