Civil Engineering Reference
In-Depth Information
Table 5.4
(
continued
)
Table b) - Indicative drive lengths (e.g. between shafts) and maximum number of drives
Excavation technique
0.9 m
0.9 m
1.0 m
1.2 m
1.35 m
1.5 m
1.8 m
1.8 m
Pipejack - machine; remote operation
from surface
Drive length limited only by
capacity of jacking system
250 m
400 m
500 m
(7)
500 m
(7)
Man entry not
acceptable
Avoid
man entry
Pipejack - machine; operator controlled
below ground
500 m
(7)
Not acceptable
125 m
200 m
300 m
500 m
*25 m -
2 drive
lengths
*50 m -
2 drive
lengths
*75 m -
2 drive
lengths
*100 m
1 drive length.
Plan to use minidigger
if over 2.1 m dia.
Pipejack - hand dig
(6)
Not acceptable
Tunnel - machine; operator controlled
+ mechanical erector
500 m
(7)
Not acceptable
*250 m
*500 m
Tunnel - hand dig + mechanical
erector
(6)
*50 m
1 drive
lengths
*100 m
1 drive length.
Plan to use minidigger
if over 2.1 m dia.
Not acceptable
Not acceptable
*25 m - 2 drive lengths. Minimum cross
section inside frames 1.2m high
Timber heading - hand dig
(6)
1.0m wide
