Fig. 5
From: Stress distribution characteristics of overburden strata during thick coal seam top coal caving

Characteristics of overburden strata collapse in the mined-out area after the top coal caving of thick coal seams. (a) Time step of 1 × 103; (b) time step of 5 × 103; (c) time step of 2.5 × 104; and (d) time step of 5 × 104.