Study on triaxial compression mechanical properties and reinforcement mechanism of reinforced backfill

XU Wenbin; ZHOU Kun; ZHANG Yalun; CHEN Wei

doi:10.13247/j.cnki.jcumt.20250419

Abstract：Aiming at the problem of easy collapse of backfill in downward slicing and filling mining,geo grid reinforcement technology is applied to the backfill to improve the strength of the artificial roof backfill.Triaxial compression tests were conducted on geogrid-reinforced backfills with rein-forcement positions of 1/3H,1/2H,and 2/3H and geogrid mesh sizes of 2,3,and 4 mm.The ef-fects of confining pressure,reinforcement position,and mesh size on the mechanical properties and failure characteristics of the reinforced backfills were investigated.The research results show that compared with the unreinforced backfill,the geogrid-reinforced backfill exhibits higher peak strength and more significant plastic deformation characteristics.There is an interaction effect be-tween the mesh size of the geogrid and the reinforcement position.When the reinforcement posi-tions are 1/3H and 2/3H,the peak deviatoric stress of the reinforced backfill shows a trend of first increasing and then decreasing with the reduction of mesh size;when the reinforcement position is 1/2H,the peak deviatoric stress of the reinforced backfill increases with the decrease of mesh size.With the increase of confining pressure,the decrease of mesh size,and the downward shift of the reinforcement position,the failure mode of the geogrid-reinforced backfill gradually transforms from shear-slip failure to shear-dilation failure or bulging failure.The presence of the geogrid can inhibit the propagation of cracks and sliding surfaces within the backfill.The reinforced zone formed by the synergistic effect between the geogrid and the top layer with a high cement-sand ratio,together with its lateral confinement effect,enhances the mechanical properties of the geogrid-reinforced backfill.The above research results can provide theoretical support for the practical application of geogrid-reinforced backfill in mining engineering.