JJ-RRCAMP-08 - Sudes Caltrops

The outline of the camp was usually marked by a ditch, with the resulting spoil used to make a rampart thrown up on the camp’s inner edge. This was then reinforced with earthen sod and strengthened by stakes carried by the troops.
When a camp was being constructed out of reach of an enemy, the entire force, except for a small picket, would participate in the building process. When the enemy was near at hand, the precaution was that half the infantry and all the cavalry would be drawn up in battle order to guard the workers building the camp. The first legion on the scene would take up defensive positions and the actual work on the camp would not begin until the arrival of the next legion in the line of march.