Experimental Investigation of Water-Inrush Risk Based on Permeability Evolution in Coal Mine and Backfill Prevention Discussion

Abstract

Induced by coal mining, the fractures constantly occur in geologic strata until failure occurs, which provide channels for water flow. Therefore, it is essential to investigate the permeability evolution of rocks under load. Borehole sampling was conducted in a bedrock layer beneath an aquifer, and the permeability evolution of sandstone specimens under different confining pressures was tested in rock mechanics testing laboratories. The results indicated that the permeability gradually decreases with the increasing confining pressures, while the peak strength increases with the increase of confining pressures. The minimum and maximum permeabilities occurred in the sandstone specimens that were subjected to elastic deformation and strain-softening stages, respectively. The failure, and maximum permeability, of these sandstone specimens did not occur simultaneously. To prevent the flow channel being formed due to the development and failure of rock fractures, a method of backfill gob was proposed and also the influence of backfill on fracture development was discussed.

Determining the Seepage Stability of Fractured Coal Rock in the Karst Collapse Pillar

“…A large number of experiments have shown that water-inrush or coal and gas outburst accidents caused by seepage loss in mining projects are often caused by sudden changes in the seepage parameters. erefore, a dynamic method should be used to study the non-Darcy seepage differential dynamic system of fractured coal rock [34][35][36]. For one-dimensional (1D) passive flow, the 1D non-Darcy seepage dynamics equations of fractured coal rock can be expressed as…”

Control of Water Inrush from Longwall Floor Aquifers Using a Division Paste Backfilling Method

“…This technology can control the depth of the bottom plate damage and can play a better role in groundwater resources [27][28][29][30]. The protective effect of the coal mine, especially under the condition of coal mining under confined water, can significantly improve the safe production conditions of coal mines [31][32][33][34]. Furthermore, this technology can effectively control the surface subsidence and deformation to achieve nonrelocation of coal mining, which can greatly improve coal resources.…”