Optimization Of Reasonable Mining Parameters Based On The Cooperative Effect Of "Backfill-coal Pillar"

The problem of residual coal is widespread in major mining areas in China,and there is a great waste of natural resources.At present,the coordinated mining method of "mining reserving filling" has obvious advantages in controlling surface and overburden migration,improving resource recovery rate and reducing filling cost,and the co-bearing mechanism of"backfill and coal pillar" is the key to coordinated mining of "mining reserving filling".Therefore,this paper conducts systematic research on reasonable mining parameters under the common bearing capacity of "backfill-coal pillar".Taking "backpack-coal pillar" composite support body as the research object,the failure characteristics and stress-strain characteristics of "coal pillar","backfill" and "backfill-coal pillar" composite support body are tested by uniaxial compression test.Using PFC2D simulation software,the composite support of four Angle "backfill-coal pillar" ratio,width,height and strength simulation in the four types of composite under the conditions of uniaxial compression support body,the scope and failure form of composite support body of elastic and plastic zone width and peak stress function expression,reveal "backfill-coal pillar"common bearing mechanism.Based on the semi-inverse solution method of elastic mechanics,the mechanical model of "backfill-coal pillar" was established to analyze the stress and elastic-plastic zone distribution of the support body,and the optimal parameter calculation method of "backfill-coal pillar" was given.Through the existing research results(30m width of mining,16m width of coal pillar mining,41m width of the filling,its recovery rate<84.4%,filling rate>35%),and the theoretical calculation of the optimized for filling mining width parameter 38m,composite support body width 60m(14m width of coal pillar,46m width of filling,its recovery rate<85.7%,the fill rate>47%)compared to verify,basic consistent.This paper provides theoretical basis for the coordinated mining method of "mining reserving filling",and has reference value for the residual coal mining area,"three unders"mining and the ecological environment protection of mining area..