AL Tunnel Practice Questions - Alabama Tunnel Contractor Examination Exam

Invert is the floor, crown is the top, and springline is the mid-height at the sides Invert is the top of the lining, crown is the floor, and springline is the shaft collar Invert is the TBM cutterhead, crown is the muck skip, and springline is the laser Invert is the access shaft, crown is the reception shaft, and springline is the jacking frame