Research Article
Research on Failure Mechanism and Strengthening of Broken Roadway Affected by Upper Coal Pillar
Figure 7
Distribution of principal stress difference under the upper coal floor. (a) #16 coal seam floor. (b) #16 coal seam roof. (c) 7 m above #16 coal seam. (d) 14 m above #16 coal seam.
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| (b) |
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