Mechanism of Secondary Breakage in the Overlying Strata during Repetitious Mining of an Ultrathick Coal Seam in Design Stage

<div>Variation of maximum tensile stress on the hanging block with <i>l</i><sub><i>x</i></sub> for different values of <i>H</i> and <i>h</i>: (a) block thickness <i>h</i> = 15 m; (b) load height <i>H</i> = 100 m.</div>

Advances in Civil Engineering

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Figure 9

Figure 9: Mechanism of Secondary Breakage in the Overlying Strata during Repetitious Mining of an Ultrathick Coal Seam in Design Stage 