Table 1: Summary statistics for the discontinuity frequency and ranges of Schmidt rebound, and RQD (%) values of the dacites in different weathering grades (NE: negative exponential).

Weathering grade

Number of discontinuity

Mean discontinuity spacing (m)

Discontinuity frequency (m)

Standard deviation

Distribution

SHV

RQD (%)

I

171

0.969

1.03

0.769

NE

50–100

II

169

0.826

1.21

0.853

NE

50–100

III

179

0.508

1.97

0.388

NE

0–50

IV

231

0.405

2.47

0.312

NE

0–50

Level of significance for means of discontinuity spacing: 95%.