Failure Mechanism and Control Technology for a Large-Section Roadway under Weakly Cemented Formation Condition

Figure 4

Roof caving accident in Haizi Mine. (a) Water release through drill hole at the roof. (b) Roof caving. (c) Fractured joint surface. (d) Separated anchor bolts and anchor ropes.

(a)

(b)

(c)

(d)