Engineering geology aspects for design and classification - Tunnel Engineering: Basics and Additional Services for Design and Construction - page 60

Table 2-22 Guideline values for L1, L2, L3, n, H, p, S and q (SIA-198, Table 7) [218].

Max. excavation width [m] 3 6 10 15

Tunnel (clause 5 23 2)
L1 Face area [m] 2 3 5 5

L2 Advance area [m] 15 20 25 35

L3 Rearward area [m] 150 200 250 300

n Number of rock bolts per running m tunnel 2 4 5 9

Excavated shafts (clause 5 23 3)
H Working area 2 3 5 5

p Number of rock bolts per running m shaft 6 12 18 27

Sunk vertical shafts (clause 5 23 4)
S Working area [m] 6 6 6 6

q Number of rock bolts per running m shaft 3 6 9 13

Table 2-23 Matrix of the excavation types and excavation classes for drill and blast (SIA-198, Table 6)
[218].

Excavation types Excavation classes

I II III IV V

A Full-face excavation A I A II A III A IV A V

B Top heading B I B II B III B IV B V

C Divided top heading C III C IV C V

D Side headings D III D IV D V

Table 2-24 Excavation classes (AK) for drill and blast (simplified).

AK I AK II AK III AK IV AK V

L1... < 9 rock bolts < 9 rock bolts

mesh & shotcrete
< 1/3 U

steel arches
shotcrete > 1/3U

HEB rolled steel
sets +
Marciavanti

L2... mesh & rock

bolts
against rock fall

≤ 27 rock bolts
mesh & shotcrete
< 1/3 U

> 27 rock bolts
mesh & shotcrete
> 1/3 U

L3... > 27 rock bolts
mesh & shotcrete
> 1/3 U
L1: Face area ........................ 5 m
L2: Advance area: ................ 35 m
L3: Backup area ................... 300 m





for excavated span b = 12 m

n: number of rock bolts per tunnel n = 9
u: circumference