6.7
Properties (03 47xxx)
03 47001
dimensional creep
difference between actual advance of an assembly (01) and the theoretical advance
03 47002
ironbound
condition arising from a change of alignment, where the tail of a tunnel shield (03 46032) binds against a preformed tunnel lining (03 42005)
03 47003
lead
distance that one side of a tunnel lining (03 42005) or a tunnel shield (03 46032) is in front of the other
03 47004
look up
distance that the bottom of a tunnel lining (03 42005) or tunnel shield (03 46032) is in front of the top
03 47005
overhang
distance that the top of a tunnel lining (03 42005) or tunnel shield (03 46032) is in front of the bottom
03 47006
rock mass rating
empirical geomechanical classification for quantitively assessing rock (03 23027) and predicting tunnel (01) support requirements
03 47007
closed mode
characteristic (01) of a shield machine (BS EN 12336) that maintains support of the tunnel face (03 42019) while advancing
03 47008
gauge pressure
air pressure measured by gauge (12 86029) above atmospheric pressure
03 47009
hydrostatic balance
at a particular level, balance between pressure of air in a tunnel (01) and ground water (BS ISO 6107-1) pressure
03 47010
tunnel air pressure
pressure of air in a tunnel (01)
03 47011
air loss
quantity of compressed air (BS EN 12110) lost, measured at atmospheric pressure
03 47012
stand-up time
03 47013
overburden pressure
pressure in the horizontal plane at a given depth (01) due to the weight (11 27002) of overburden (03 23019)
03 47014
water head
head (01) of water
03 47015
tunnel arch
6.8
Spaces (03 48xxx)
03 48002
relieving hole
hole to break rock (03 23027) and thereby control and localize the effects of the initial blast in a round (BS 5607)
NOTE Usually 75 mm to 100 mm in diameter.
03 48003
cut
group of shot holes (03 28001) surrounding a relieving hole (03 48002)
03 48004
burn cut
cut (03 48003) in which all the shot holes (03 28001) are parallel
03 48005
confined space
space (01) with restricted ventilation where there is a reasonably foreseeable risk to health and safety
03 48006
air bubble
space formed in the upper part of the slurry (01) compartment of a slurry machine (03 46111) in which compressed air (BS EN 12110) is used to maintain the slurry (01) at a pressure appropriate to the conditions at the tunnel face (03 42019)
03 48007
wedge cut
cut (03 48003) in which central shot holes (03 28001) start in a pattern of two vertical lines and converge in pairs to encompass a wedge-shaped block (01) of rock (03 23027)
03 48008
trimming hole
shot hole (03 28001) on the perimeter of an excavation (01) to define its profile (01) and fired last
03 48009
injection point
6.9
Miscellaneous (03 49xxx)
03 49001
deoxygenated air
air with a reduced amount of oxygen
03 49002
blackdamp
air found in tunnels (01) and mines; it has less oxygen than normal but more carbon dioxide
03 49003
firedamp
flammable mixture of methane and other gases
03 49004
explosive atmosphere
mixture of flammable substances in the form of gas, mist or dust in which, after ignition, combustion spreads rapidly throughout the unconsumed mixture
03 49005
potential explosive atmosphere
atmosphere that could become an explosive atmosphere (03 49004)