A numerical study of the mining‐induced energy redistribution in a coal seam adjacent to an extracted coal panel during longwall face mining: A case study

Abstract

Mining of the coal seam adjacent to the extracted coal panel is widely practiced in China to improve coal resource recovery rates, but the energy change associated with longwall mining may present a new risk to ground stability and gateroad failure. To understand the energy change effectively, a meticulously validated numerical model, built using FLAC3D software, incorporating a double‐yield model for the gob materials and a strain‐softening model for the coal/rock masses, was developed to investigate the energy redistribution in coal seams and barrier pillars during the process of mining the coal seam adjacent to the extracted coal panel. The model results showed that the closer the region was to the LW 5301 gob, the higher the location and magnitude of the peak strain energy density. Consequently, the risk of rockburst in coal seams was greater than that in barrier pillars. Along the coal seam strike, with increasing advancing distance from the setup room, the magnitude of the peak strain energy density gradually increased to 1.88‐2.78 times the premining energy level. In addition, along the coal seam dip, the maximum distance from the peak strain energy density to the edge of the coal seam was approximately 16‐28 m, which is greater than that in the barrier pillar. The proposed numerical simulation procedure and calibrated method could be a viable alternative approach to evaluate longwall mining‐induced energy changes.

Fracture Characteristics and Geometric Fractal of Damaged Sandstone under Impact Load

“…In addition, the more the number of cracks, the more times the stress wave will be emitted and transmitted, that is, the more cracks the stress wave passes through, the more the attenuation times will occur. When the gap is larger, the amplitude of attenuation will be greater [30].…”

Subsurface strata failure and movement based for improving gas emission control: Model development and application

“…The rock permeability is the main parameter characterizing the rock permeability. 45 When the overlying strata are affected by mining, factors such as in situ stress and temperature change to different degrees, while the permeability of the strata may vary with these factors. Generally speaking, when the coal seam is mined, the overlying strata are disturbed and broken and bended to different degrees forming "vertical three zone" from underground to surface, as shown in Figure 5:…”

Discrete element simulation for investigating fragmentation mechanism of hard rock under ultrasonic vibration loading

“…However, research on rock fragmentation mechanism has been limited because of the difficulty in measuring microcracks in real time during high‐frequency vibration laboratory tests 20 . With the rapid development of computer technology and advanced numerical techniques, computational simulations help us overcome this limitation and determine the characterization of crack initiation and growth in more detail 21‐27 . In recent years, the DEM has received considerable attention for its use in modeling the dynamic process of rock failure owing to its three advantages 28‐31 .…”

“…20 With the rapid development of computer technology and advanced numerical techniques, computational simulations help us overcome this limitation and determine the characterization of crack initiation and growth in more detail. [21][22][23][24][25][26][27] In recent years, the DEM has received considerable attention for its use in modeling the dynamic process of rock failure owing to its three advantages. [28][29][30][31] Firstly, considering its micromechanical foundation, the DEM is a useful simulation tool for understanding the dynamic mechanism of rock materials at a microscale directly.…”