Rock Mass Classification for Columnar Jointed Basalt: A Case Study of Baihetan Hydropower Station

Figure 7

Illustration of microcrack in columnar jointed basalt of PD37: (a) the original photo of adit wall, (b) geologic sketch map of adit wall, (c) the original photo of adit top, and (d) geologic sketch map of adit top.

(a)

(b)

(c)

(d)