Q method chart descr 2013

ROCK MASS OUALITY AND ROCK SUPPORT
G	F	E	D	c	B	A
Exceptionally poor	Extremely poor	Very poor	Poor	Fair	Good	Very good	1 Extremely |Excep. good I good

RQD J J

Rock mass quality Q =-x — x —

J J SRF

n    a

RRS - spacing related to Q-value

Si30/6

D

016

c/c

Si30/6 016-020 (span 1 Om)

D40/6+2 016-20 (span 20m)

Si35/6 016-20 (span 5m)

D45/6+2 016-20 (span lOm)

D55/6+4 020 (span 20m)

D40/6+4 016-20 (span 5 m)

D55/6+4 020 (span 10 m)

D70/6-f6 020 (span 20 m)

- Single layer of 6 rebars.

30 cm thickness of sprayed concrete

= Double layer of rebars

= Rebardiameter is 16 mm

= RSS spacing. centre - centre

Supporł categories

® Unsupported or spot bołting (D Spot bolting SB

(3) Systematic bolting fibr© reinforced sprayed concrete, 5-6 cm B+Sfr

@ Fibr© reinforced sprayed concrete and bolting. 6-9 cm. Sfr (E500)+B

Fibrę reinforced sprayed concrete and bolting. 9-12 cm Sfr (E700)+B

Fibrę reinforced sprayed concrete and bolting, 12-15 cm + reinforced ribs of sprayed concrete and bolting Sfr (E700)+RRS I +B

© Fibrę reinforced sprayed concrete >15 cm + reinforced ribs of sprayed concrete and bolting Sfr (E1000)+RRS ll+B

® Cast concrete lining CCA or Sfr (E1000)+RRS lll+B

® Special evaluation

Bolts spacing is mainly based on 020 mm

E = Energy absorbtion in fibrę reinforced sprayed concrete

ESR = Excavation Support Ratio

Areaswith dashed lines have no empirical data

1

0.001

0.004 0.01

1    4    10    40    100    400

Bolt length in m for ESR =