Research on Failure Mechanism and Strengthening of Broken Roadway Affected by Upper Coal Pillar

<div>Principal stress difference distribution between single and double layer mining. (a) #15 coal seam in exploited conditions. (b) #15 coal seam in unexploited conditions.</div>

Advances in Civil Engineering

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Figure 9

Figure 9: Research on Failure Mechanism and Strengthening of Broken Roadway Affected by Upper Coal Pillar 