| 释义 |
spad1 orig. U.S.|spæd|
[Var. of spud n.]
A spike with a flattened end containing a hole to support a plumb-line, so that it can be driven into a tunnel roof to provide a marker.
1908L. W. Trumbull Man. Underground Surveying iii. 93 A majority of the mines of the United States are using punched horseshoe nails known as ‘spads’. The head of the horseshoe nail..is hammered flat and a hole punched through it. 1957R. C. A. Hooper Winiberg's Metalliferous Mine Surveying (ed. 4) ix. 186 Some surveyors prefer to have the width of the spad along the longitudinal axis of a drive rather than at right angles. 1973B. A. Barry Construction Measurements xvi. 220 Line is carried forward in tunneling by tape and theodolite to marks placed either on the floor or side or roof of the tunnel. Driving plugs and spads into the roof to serve as horizontal control (traverse) points keeps them free from traffic damage or disturbance. |