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47.3.3
Stake/Check point on
surface
Roads - Tunnel
6.
Position the drill bit to the laser point on the tunnel face.
Example:
d2
d1
a
Tunnel_033
a
Chainage 10
b
Chainage 15
c
Chainage 20
d
Centreline
d1 Height offset at defined chainage 10
d2 Height offset at defined chainage 15
☞
Stake face point 1 at chainage 10 (point1). Stake face
point 1 at chainage 15 as defined at chainage 10. Position
and direction at chainage 15 are a result of the Offset,
Height offset and drilling angles as defined for chainage
10.
7.
Now the jumbo boom moves onto line between the laser point on
wall and the telescope so that the laser now points at the back of
the boom. Press Fn Tools. Select Check Jumbo position to get the
delta values which are used by the drilling rig to move the boom for
the correct drilling direction.
Stake profile and Check profile
c d
e
b
f
a
Tunnel_021
If it is not possible to stake out the defined point between successive itera-
tions, the instrument will maintain the chainage and height difference from the
vertical alignment fixed. The horizontal offset from the centreline to calculate
the new position of the point are modified. The point that will be staked out
will thus maintain the defined chainage and height difference but will have a
modified offset value from the centreline.
c
b
d
a
b
c
d
e
f
Centreline
Design point to stake out
Excavated profile
Design profile
Centreline offset
Centreline height difference
829
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