Research On Settlement Of Overlying Strata In Stope Filled With Flexible Formwork And Coal Gangue

Filling mining technique cemented with coal gangue and flexible formwork is a new filling mining method,the technique has a complete independent intellectual property rights in our country, which belongs to the green mining technology.The technology uses broken coal gangue and fly ash as filling material,with flexible formwork sealing slurry,its construction process is simple with high construction efficiency and its backfill has high early strength,high filling percentage and tight-filling ratio,so it can effectively control movement and deformation of overlying strata and surface.This paper uses E1302 working face of Gao-He coal mine as the engineering background, established mechanical model of filling area and waiting filling area in backfill mining cemented with coal gangue and flexible formwork,and systematically studied the characteristics of strata behaviors and the law of movement and deformation of overlying strata and surface in stope filled with flexible formwork and coal gangue uses theoretical analysis, laboratory tests, numerical simulation and industrial test. The main results are as follows:(1)The establishment of two mechanical models of filling area and waiting filling area in backfill mining cemented with coal gangue and flexible formwork based on Winkler elastic foundation beam theory were established by analyzing geological conditions of Gao-He coal mine, existing filling technology and filling mining technique cemented with coal gangue and flexible formwork.(2)Got the relationship between deflection of goaf roof, surface subsidence and mechanical properties of backfill, as well as rock beam of limit span in waiting filling area through systematic analysis of the two mechanical models after analyzing the interaction mechanism between overlying strata and backfill in filled stope of backfill mining cemented with coal gangue and flexible formwork.(3)The mechanical model were simulated by FLAC3 D based on different backfill strength, different filling percentage, the results show that: Compared to increase the strength of backfill, more significant results obtained on control activities of stope wall rock by increasing the rate of filling. Finally, the maximum subsidence of the surface is predicted, and the forecast results were compared with the simulation results,because the damage of the ground buildings can be controlled in the first degree, there is no need to reinforce or maintain the ground buildings, not to move the village, so reached the purpose of filling.