Parameter

Description

Value

RQD

40 - 50

40 - 45

Jn

Three joint sets with random to four joint sets

12

Jr

Smooth to planar

1

Ja

Softening or low friction clay mineral coatings

4

Jw

Dry to medium inflow of pressure

1 - 0.66

SRF

Medium stress, favorable stress condition

1

Q

0.62 - 0.83

Class No.

Very poor rock