Tunnel - Elements For Stake And Check Measurements; Staking Tunnel Faces; Horizontal And Vertical Offsets; Distance Along Profile - Leica Captivate Technical Reference Manual

Superelevation
43.6.14
Tunnel face
700
c
a
b
Tunnel_003

Tunnel - Elements for Stake and Check Measurements

Staking tunnel faces

It is usually required to stake out the tunnel face to indicate the position to
excavate when certain tunnelling methods are used. For example, Drill and
Blast or excavation using a roadheader.
The points to stake on the tunnel face can be defined in various ways:

Horizontal and vertical offsets

By horizontal and vertical offsets with respect to the centreline:
a
d
Tunnel_004

Distance along profile

By the distance from the start of the design profile and an offset from the
design profile.
b
e
d a
c
Tunnel_005
a
b
c
d
d
e
e
a
b
b
c
c
d
a
b
c
d
e
Centreline or axis
Rotation point
Centreline offset
Centreline height offset
Superelevation (Rotation)
Centreline
Point on tunnel face to stake
Centreline offset
Centreline height offset
Centreline
Point on tunnel face to stake
Point defining start of design
profile
Distance from start of design
profile
Offset perpendicular to design
profile
Roads - General