Physical Modeling of the Controlled Water-Flowing Fracture Development during Short-Wall Block Backfill Mining

Abstract

Short-wall block backfill mining (SBBM) technology is an effective method to solve the environmental problems in the mining process. Based on the technical characteristics of SBBM technology and the physical similarity criterion, the physical similarity models for comparing the control effects of water-flowing fracture (WFF) development using short-wall block cave mining (SBCM) and SBBM were established, and the deformation and the WFF development of overlying strata above gob were monitored. The test results determined that the composite materials of 5 mm thick pearl sponge+5 mm thick sponge+10 mm thick paper+6 mm thick board were adopted as the similar backfill materials by comparing the stress-strain curves between the similar backfill materials and the original gangue sample. When the backfilling body was filled into the gob, it would be the permanent bearing body, which bore the load of the overlying strata accompanied with the protective coal pillar. At the same time, the backfilling body also filled the collapse space of overlying strata, which was equivalent to reduce the mining height, and effectively reduced the subsidence and failure height of the overlying strata. Compared with SBCM, the test results showed that the maximum vertical deformation, the height of water-flowing fractured zone, and activity range of overlying strata using SBBM were reduced by 91.4%, 82.5%, and 64.9%, respectively. SBBM had a significant control effect on strata damage and WFF development, which could realize the purpose of water resource protection in coal mines.

Study on Deformation Response Law of Surrounding Rock in Solid Backfill Mining Stope

“…Through the above analysis of the movement characteristics of surrounding rock in traditional natural caving mining, caving mining has caused great environmental problems (such as farmland destruction, gangue accumulation, road damage, house cracking, etc.). In order to solve such environmental problems caused by mining without restricting the normal production of coal resources, and then achieve the purpose of protecting surface damage and realizing the reuse of gangue and the green development of coal resources, the backfill mining technology came into being [18][19][20][21]. Solid backfill technology is a mixture of coal gangue and flyash and other backfill materials, through the shaft and transport equipment to the face area and then filled and compacted, to control the role of the overburden movement deformation of the face area.…”

Short-wall paste continuous mining and continuous backfilling for controlling industrial square surface subsidence

“…Backfill mining is a technology developed in the past decade and can be used to control surface subsidence as well as protect buildings and structures in the industrial square by reducing the equivalent mining height. At the same time, the backfill method with coal gangue as the main raw material can effectively solve the problem of gangue disposal while protecting the fragile ecological environment in west China (Zhang et al, 2021a;.…”

Research of the Backfill Body Compaction Ratio Based on Upward Backfill Safety Mining of the Close-Distance Coal Seam Group

“…Additionally, in the process of coal mining, a large amount of gangues is discharged and accumulated to the surface, threatening the ecological environment of the mining area. Meanwhile, the construction of green mines [6][7][8][9] is constantly advocated by the government and relevant national and local policies have been issued for gangue discharge, calling for the backfilling of gangue to goaf. In this study, upward backfill mining is proposed to improve the coal recovery rate, reduce the damage range of overburden strata caused by lower mining, and reduce the emission of gangue, so as to provide an effective and feasible method to solve the above problems.…”