Definition - What does Advance mean?
Advance refers to the forward distance traveled during excavation over a given period. It should be distinguished from the advance rate, which is a measurement of the speed of advancement. The term is closely identified with the progress made toward the completion of a trenchless construction operation.
Trenchlesspedia explains Advance
In layman’s terms, an advance is a forward movement. The word could apply to the movement of troops or steps forward in a career. As a technical term in trenchless construction, advance refers to the forward movement of a drill string in a drilling operation or incremental increases in the excavation of a tunnel.
Trenchless construction managers look for key performance indicators to measure success. Perhaps the greatest indication of progress is the distance traveled toward completion of the progress. When reduced to numbers, these indicators serve as milestones to assist in project planning and evaluation.