Quantitative Evaluation of Isolated Overburden Grout Injection Technology Based on Large-Deflection Inclined Thin Plate Combined with Slurry Modeling

Abstract In the Quaternary thick loose layer covered mining area, the Isolated Overburden Grout Injection technology has been widely applied and has provided effective ground subsidence management. For the process of mechanical action on the important strata, the stresses generated externally by the slurry in the Bed-separation cavities remain a study open question. In this paper, a large deflection mechanical model of inclined principal key strata (PKS) thin plate under the action of bed-separation slurry is constructed based on the large deflection of thin plate, the principle of energy law, fracture mechanics, and non-Newtonian hydrodynamic theory. The 7221 work face mining in Anhui Province, China, the height of the caved zone, fractured zone, continuous bending zone, and the placement of each important strata are all inferred by the model using the drilling holes’ physical and mechanical parameters. Assuming 7221 work face Longwall mining, the maximum deflection and volume of PKS are calculated and verified with 3DEC numerical simulation. Based on iso-volume, calculate the ground-moving basin inscribed function. The factors related to the grouting hole are analyzed, specifically focusing on the deflection and ground subsidence engraving function of the PKS in Isolated Overburden Grout Injection mining. The accuracy of PKS deflection after grouting was verified using 3DEC. The Small Baseline Subset (SBAS) technique was also employed to interpret satellite pictures from Sentinel I-A for ground subsidence monitoring. Model calculations, SBAS monitoring results, and measurements were cross-validated. This paper aims to quantitatively analyze deflection values, deflection volumes, and maximum ground subsidence for the PKS under two mining methods: Longwall mining and the Isolated Overburden Grout Injection technology. Applying the technology in the mining field involves deducing the mechanical mechanism and thoroughly verifying the actual subsidence and reduction impact.