Research On Movement And Deformation Of Overlying Strata And Strata Behaviors With Backiflling Mining Method

First based on the mining and geological conditions of one mine in Illinois, US,selection of backfilling mixes and backfill flow characteristics were studied; On thisbasis, engineering properties, such as slake durability, permeability, swelling, bleed,slump, leachate and strength with different curing time of backfill, were analyzed, andmechanism of action for the stability of coal pillar and the effects of backfilling wereanalyzed under the condition of room-and-pillar mining method with cementedbackfill. For the longwall backfilling mining technology in coal mines, on the basis ofcomprehensive analysis on the general characteristics of movement and deformationof overlying strata and bearing force characteristics of backfill, using the the theoriesof beams on elastic foundation and multiple supports, mechanical models were builton the condition of long-wall mining with backfilling, with which basic differentialequations of deflections were obtained. All the factors affecting movement anddeformation of overlying strata, the distribution of the front and rear abutmentpressure, and shearing force of immediate roof were analyzed through the analyticsolutions from these differential equations. On that basis, finite element analysismethod was used to explore the dynamic changing regularity of displacement fieldand stress field of overlying strata.