Study of the Backfill Confined Consolidation Law and Creep Constitutive Model under High Stress

Abstract

Abstract To better understand the mechanical behavior of the compression deformation of backfill under high stresses corresponding to large depths, consolidation compression tests were performed for cemented tailings backfill with a cement-sand ratio of 1:10 and a concentration of 70 % under confined conditions. After applying different loading stress functions from 0.5 to 32 MPa, the final axial deformation of the test specimen of backfill was obtained, and the micromorphology of backfill was studied before and after consolidation by scanning electron microscopy. Additionally, fitting analysis was performed for backfill confined compression deformation data and device model constitutive equations by the minimum square law, and the constitutive model was revised according to the analysis results. The research results indicate that as the load increases, the void ratio e obeys the functional relationship e=algt + b with compression time t. Under the high-stress conditions of confinement, the constitutive model of backfill consolidation and creep can be used to describe the creep behavior of the backfill. Under high-stress conditions, after the consolidation of the confined backfill, the space between the tailing particles diminishes, the particles become more compact, and particle slippage occurs.