Wiktionary
field works
n. (field work English)
Usage examples of "field works".
Military architecture embraces fortification and field works, which with their bastions, curtains, hornworks, redoubts etc.
Attacking the field works on Cemetery Ridge left him leery of moving against positions prepared years in advance and filled with guns bigger than any that could keep up with an army on the move.
Apparently, when it comes to professional status, your field works differently than mine.