New Method to Design Coal Pillar for Lateral Roof Roadway Based on Mining‐Induced Stress: A Case Study

Abstract

The traditional method to design coal pillar for lateral roof roadway was established based on the mining-induced strata movement contour which is considered as a straight line, while ignoring the variations of the internal strata deformation law as well as stress distribution characteristics. In order to make up for this deficiency, in this study, evolution of mining-induced stress in the overlying strata was simulated using physical and numerical simulations, and a method to design coal pillar for lateral roof roadway based on mining-induced stress was proposed. The results indicate that the stress of the overlying strata is redistributed during excavation, and the stress distribution can be divided into a stress-relaxation area, a stress-concentration area, and an in situ stress area. The contour line of 1.05 times the in situ stress is used to define the mining-induced stress contour. Stress inside the contour is redistributed while outside the contour the overlying strata are still within the in situ stress area. Mining-induced stress contour presents a concave-upward type from coal seam to the overlying strata that cannot be merged into a straight one due to their different characteristics of movement and deformation. With this in mind, this study proposed a method to design the width of coal pillar for lateral roof roadway according to the mining-induced stress contour. According to mining-induced stress contour, the width of coal pillar for lateral roof roadway of longwall panel 31100 is 160 m, and the maximum deformation of the roadway is 270 mm. The new method can definitely meet engineering demands.

Method to Calculate Working Surface Abutment Pressure Based on Key Strata Theory

“…During the course of mining, the overlying strata are shifted and stress is redistributed to the surrounding rock, resulting in abutment pressure. Failure to account for abutment pressure distribution leads to coal mine hazards, such as rockbursts, coal and gas outbursts, and roadway deformation and instability [1][2][3][4][5][6][7][8][9]. Forecasting and preventing these hazards, controlling the surrounding rock in mining roadways, determining a reasonable width for protection coal pillars, and designing the layout of mining roadways are all based on the distribution of abutment pressure.…”

In situ fluidized mining and conversion solution to alleviate geological damage and greenhouse gas emissions due to coal exploitation: A numerical analysis and evaluation

“…The horizontal demarcation line has a value 1.05 times the measured in situ stress according to previous studies. [59][60][61] The stress F I G U R E 7 Vertical stress distribution at different excavation distances for the (A) fluidized and (B) traditional mining methods…”

The Development Law of Mining-Induced Surface Cracks in Shallow Coal Seam Through Double Gullies Terrain: A Case Study in a Mine

“…Yushen Coalfield is located in the transition zone between the Loess Plateau and the Mu Us Sandy Land with rugged topography, and a gullied surface [9], under gullies topography, mining-induced surface cracks is a severe threat to the local fragile ecological environment [10][11][12][13]. Researchers have studied the influence of valley topography on mining-induced surface cracks using numerical simulation [14][15][16][17],…”