Term | Definition |
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Pedestrian |
A person traveling on foot
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Penetration rate |
The optimum speed with which a drill or excavator can advance through the ground in a short time before it is slowed or stopped by mechanical breakdown, ground instability, or the like.
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Perfo aleeve |
Two perforated half round sections of sheet metal which are filled with grout, wired together, and installed in a hole. A steel bar with a rounded nose is forced inside the aleeve, causing the grout to squeeze through the perforations and bond to the sides of the hole.
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Permanent ballast |
Non-structural solid material placed inside or outside an immersed tunnel to increase its effective weight permanently
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Physiological issues |
Issues pertaining to health or the functioning of living things
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Pilot tunnel |
A small tunnel excavated over the entire length or over part of a larger tunnel, to explore ground conditions and/or to assist in final excavation. May also be referred to as "pilot drift".
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Pipe jumbo |
Traveling support for the discharge line from a concrete placer.
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Plenum method |
Excavating a tunnel under air pressure.
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Poling board or plate |
See forepoling
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Pollution |
Interference with a natural system that is potentially harmful or unwanted
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Popping rock |
An overstressed rock condition involving the spontaneous and violent detachment of rock slabs. See also rock burst.
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Portal |
The structure or the end of the structure at the two ends of a tunnel at the interface of the covered and open sections
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Portal |
The entrance from the ground surface to a tunnel.
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Portal-in |
To start the tunnel excavation at the portal face.
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Posts |
The vertical members of a steel rib or timber support system.
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Pot |
A steel pressure vessel used for transporting concrete. At the point of placement, the concrete is ejected from the pot by use of compressed air.
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Powder factor |
Number of pounds of powder per cubic yard of rock.
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Powder monkey |
Slang for man who handles explosives.
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Pre-bagged shotcrete mix |
Pre- bagged concrete or shotcrete mix supplied in bags with all ingredients oven-dried and pre-mixed
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Pre-splitting |
A technique of inducing cracks roughly following the periphery of the rock shape to be excavated by the use of closely spaced holes and reduced explosive charges prior to main blasting; a subdivision of smooth blasting.
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