关键词: 胶结充填体, 三轴压缩, 变形破坏, 能量耗散

Abstract: The deformation failure and energy dissipation of backfill body are closely relative to confining pressure. Experiments are taken to investigate backfill body samples under uniaxial compression and triaxial compression. Based on the experimental results, the internal relations among deformation feature, failure mode, energy dissipation and confining pressure are studied and compared. The results show that the peak strain of backfill body increases with the increase of the confining pressure, and takes a linear correlation. Under a low confining pressure, backfill body has a brittle failure characteristic and presents a strain softening behavior; as the confining pressure increases, the mechanical feature of backfill body performs by a way of transformation from brittleness to strain hardening; the cement/tailing ratio and solid concentration are higher, the critical value of the confining pressure from brittle to ductile is greater. The forms of crack and fracture propagation are diverse, which can be sorted into single type, parallel type, intersection type and complex type. The main macrofailure modes are X-shaped and Y-shaped shear failure. The forms of failure plane are classified by linear smooth friction surface, arc rough friction surface, linear rough friction surface, terrace rough friction surface. The peak strength also increases linearly as the confining pressure increasing. The sensitivity of cohesion to cement/tailing ratio is higher than that of solid concentration. The deformation energy of backfill body at different compressed stages increases to a considerable extent with the increase of confining pressure. The relations of the amount of energy dissipation before yield deformation stage and after yield deformation stage, unit volume strain energy and total energy consumption take a positive proportion of the confining pressures.

Key words: cemented backfill body, triaxial compression, deformation failure, energy dissipation