Research on the Rock Pressure Behavior at Close-Distance Island Working Faces under Deep Goaf

Figure 11

Variation curve of principal stress and the distance from the roof of the goaf (alignment direction): (a) the working face advances 80 m, (b) the working face advances 130 m, (c) the working face advances 180 m, and (d) the working face advances 240 m.

(a)

(b)

(c)

(d)