Ground Control Theory And Application Of Solid Dense Backfill In Coal Mines

Coordinated with the mining technology, Fully-mechanized backfill technologyreplaces the coal resource which could not be recovered using conventional miningmethods with gangue, fly ash and other solid waste. This technology belongs to the greenmining system. It is one of significant innovation achievements of coal science andtechnology in recent years. Owning fully independent intellectual property rights, itprovides a kind of method and technology for exploiting the coal under buildings, railways,waterbodies (three unders), and the coal resource in fragile mining area. The thesis presentsoverlying strata movement and deformation, mutual relationship between supports andsurrounding rock, strata behaviors and control mechanism systematically adopting methodsof theoretical modeling, mechanics analysis, laboratory testing, numerical simulation,similar material simulation and industrial field tests after a brief introduction of backfillmining technics. The main research results and innovative achievements are as follows:(1) An elastic thin plate mechanical model of main roof were established based onoverlying strata deformation characteristics of solid backfill mining, then deflectionequation of main roof using principle of virtual work were derived, and the criticalunbroken conditions of the main roof was obtained.(2) The relation curves between maximum tensile stress of main roof and hydraulicsupport strength, filling ratios for solid backfill mining according to the unbrokenconditions of the main roof were obtained. Breakage of main roof is mainly determined byfilling ratios. The relationship of maximum subsidence value and hydraulic support strengthp in controlled face area was obtained, and it is shown that the hydraulic support strengthcan significantly control the roof subsidence in controlled face area but with definite limit.(3) The strata movement and behavior characteristics for solid backfill mining wererevealed after analysis of numerical simulation and similar material simulation undercondition of different ratios. Research results show that overlying strata just developedbending zone and small fractured zone after solid backfill mining. And this technology caneffectively weaken strata behaviors.(4) The system layout for solid backfill mining was designed. And the filling ratio andhydraulic support strength in the field test were also designed based on research result ofelastic thin plate mechanical model of overlying strata. Industrial test was successfully performed, and good economic and social benefits were obtained.