Experimental study on floor failure of coal mining above confined water

• DOI: 10.1007/s12517-019-4250-2
• Publication Date: 2019-02-06T20:02:32Z
• Authors: Baoliang Zhang; Zhaobo Meng
• Keywords: Inrush current; Water pressure

Water inrush accidents were currently one of the most frequent forms of disaster in coal mines where the mining seams were above a major acquirer with high pressure water. Understanding the fracturing process of mining floor under the effect of highly pressurized water underneath was essential for preventing water inrush. A testing system simulating such cases was developed. This system is comprised of a simulation test bed, a confined water loading system, and a computer monitoring system. A 1900 mm (L) × 220 mm (W) × 1800 mm (H) physical model was constructed, excavated, and monitored using the testing system. The system displayed the development process of floor fractures and the formation of water inrush channels. Based on the stress distribution, the floor rock strata can be divided into five zones, stress stable zone, stress recovery zone, stress reduction zone, stress increase zone, and in situ stress zone. Overall, the floor was in a state of high shear stress under the action of rock stress and high pressure confined water, which was likely to cause shear fracturing and consequently possible water inrush into the mine working faces.