Energy Gradient

Slope of a line joining the elevations of the energy head of a stream.

Energy Head

The elevation of the hydraulic gradient at any section, plus the velocity head.

Engineer

The person, firm or corporation named as such in the contract documents; the “EngineerThe person, firm or corporation named as such in the contract documents; the "Engineer of Record". of Record”.

Entrance Pit

1) An opening in the earth of specified length and width for placing the machine on line and grade. 2) See Boring PitAn excavation in the earth of specified length and width for placing the machine on line and grade..

Entrance Seal

See Launch SealA mechanical seal, usually consisting of a rubber flange that is mounted to the wall of the jacking shaft. The flange seal is distended by the MTBM as the machine passes through the shaft. The seal is intended to prevent the flow of groundwater, soils, slurry, and lubrication into the shaft during tunneling operations..