Abstract
Abstract Retaining a waterproof coal pillar is the most effective water conservation method for a roadway close to the gob, and determining a reasonable width of the waterproof coal pillar has been a common problem among mining scholars for a considerably long time. Based on the mining of the 15208 mining face in Xinjing Coal Mine, the structure of waterproof coal pillar is divided into a mine-pressure-influenced plastic zone, an effective waterproof elastic core zone, and a water pressure failure zone. The mine-pressure-influenced plastic zone width is determined by using the limit equilibrium theory, the parabolic strength theory, and the separation variable method. The effective waterproof elastic core zone width is determined by the semi-inverse solution method, and the water pressure failure zone width is determined by considering the infiltration and softening of water. After that, combined with the previous theoretical analysis of engineering examples, the theoretical value of waterproof coal pillar width is obtained. In addition, the physical shape distribution of the waterproof coal pillar is measured by ultrasonic detection technology. The results are consistent with the field measured results. The correctness of the model is verified. Finally, the rationality of the model is verified by comparing with the previous classical models. The research results are applied to the design of the waterproof coal pillar in Xinjing Coal Mine, which could provide a theoretical basis for determining the width of the waterproof coal pillar located close to a gob.
Highlights
Due to its effective control of surface subsidence, the strip mining method is one of the most commonly used mining methods in ‘three-body’ coal mining [1]
In 2008, 707 deaths occurred in coal mines in China, while 135 deaths caused by mine water inrush accidents, accounting for 19.1% of the total, were second only to those caused by gas accidents
The results show the width of the mine-pressureinfluenced plastic zone of the waterproof coal pillar between the faces is 2.6 m
Summary
Due to its effective control of surface subsidence, the strip mining method is one of the most commonly used mining methods in ‘three-body’ coal mining [1]. The safety factor is taken into account, the accidents of waterproof coal pillar destruction and water source communication still occur. In actual production, it is very likely that the safety width of the waterproof coal pillar is not enough, resulting in mine fault water inrush and other disasters. The failure characteristics of the surrounding rocks that can be attributed to coal seam mining were considered; the mine-pressureinfluenced plastic zone and effective waterproof elastic core zone were established on the side of a coal pillar near the roadway, and the failure range caused by high water pressure in deep-buried strata or fault was considered on the side of the influence sources [36,37,38,39]. Results could provide a theoretical basis for determining the widths of the waterproof coal pillar close to a gob, eliminating the hidden trouble of the mine and realizing the safety production of the coal mine
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
