Experimental research on load-bearing characteristics of gangue polymer backfilling material

In order to effectively control the geological disasters caused by coal mining and the environmental pollution caused by gangue, a new type of gangue polymer filling material was developed with gangue as the base material.Three polymers were selected based on the performance analysis of polymers. The PFC numerical simulation software was used to analyze the stress-strain curve relationship, force chain and crack evolution during the numerical compaction test of the gangue backfill model with different particle sizes.The instantaneous and creep compression characteristics experiments of different gangue polymer filling materials were carried out by using a self-made load-bearing compression device, and the effects of different polymers and different polymer contents on the load-bearing properties of the materials were analyzed. The instantaneous and creep compressive deformation laws of the gangue polymer filling material during the load-bearing process are obtained.The research results show that the average-graded gangue has the lowest bearing compression rate, and the numerical simulation results show that the average-graded gangue with a maximum particle size of 40 mm has the best deformation resistance. The different polymer types and dosages have a greater influent on the bearing capacity of the filling body, bearing beneficial effects of styrene-butadiene rubber latex> acrylate> chloroprene rubber latex. The creep performance of the gangue polymer filling material is mainly manifested in the attenuation creep compression stage and the stable creep compression stage, and there is no obvious accelerated creep compression stage. When the content of styrene-butadiene rubber latex is 0.096 kg, with the increase of loading stress, the ratio of instantaneous deformation and creep deformation to its corresponding deformation becomes smaller and smaller, and the creep performance of the gangue polymer filler is the best. When the stress is greater than 10 MPa, the creep performance of the gangue polymer filling material is relatively stable. The filling material is suitable for most of the goafs in eastern China below 400 m and the ground pressure greater than 10 MPa.