The results indicated that the degree of asymmetric deformation of GCRICS with different coal–rock ratios progressed from small to large: 1/5, 2/5, 3/5, and 4/5. With the gradual increase in the coal–rock ratio, the thickness of the coal seam increased, the mined-out area range ...
The fracture of rocks surrounding the floor roadway during the mining of the working face of a coal mine is a complicated spatiotemporal process due to the superimposed action of multiple stress fields on the surrounding rock mass. Using the surrounding
While it may seem safer and more polite, riding single file along the limit line encourages drivers to pass cyclists in a dangerous manner, rather than change lanes to safely go around them. And it increases the likelihood that passing motorists will try to cut back in between the riders to...
The floor heave of the mining roadway is mainly caused by the post-peak deformation of the floor’s broken strata. The deformation of the roof and two sides of the roadway also exert a significant influence on the floor heave. Reinforcing the two sides of the roadway and the corners can ...
Because a single borehole cannot be arranged with too many displacement basic points, a split borehole arrangement is adopted to prevent the displacement base line from intertwining during the installation, as shown in Figure 9. Figure 9. Displacement base point arrangement scheme of high-density...
D = 0.8–1, the roadway wall is broken and collapsed. 4.1.2. Drawing of P-I Diagram Based on a large number of trial calculations, hundreds of data points corresponding to different damage degrees of the surrounding roadway wall caused by gas explosion load under the condition of no geostr...
Therefore, for the roadway with extremely broken surrounding rock, using only bolt (anchor cable) anchorage to improve the stability of the upper rock mass cannot meet the support requirements. A large number of studies have shown that grouting reinforcement can make slurry penetrate, fill, and ...
and continues to increase with and continues to increase with the distance of the face. After entering below the surface of the “1” section, the maximum shear stress of the roof increases rapidly, and the influence range is about 24 m. The maximum shear stress distribution plays a dominant...
The rock of the roof is seriously broken, and some parts of the rock have come away in blocks that are trapped by the metal steel mesh, forming a net bag shape. The rock at the corners of the roadway is also quite broken, with obvious shrinkage, and the phenomenon can be observed of...
Controlled presplitting blasting is a type of non-falling coal (rock) blasting method aimed at improving the level of coal (rock) fissures [10]. As the method can be used to effectively improve the permeability of the coal seam, it is often combined with drilling to pre-drain gas, thus ...