Abstract: In order to support the walls of an excavation and prevent a cave-in of such walls, a preliminary trench is dug and its walls shored up by means of a trench box or trench shield placed therein. A series of soldier piles are driven into the soil below the trench box or trench shield and the excavation is made deeper. Reinforcement plates are moved between and along pairs of soldier piles to a depth below the trench box or trench shield to shore up the walls of the excavation below. By the use of multi-channel soldier piles a plurality of reinforcement plates set to differing depths can be used to shore the walls of the excavation as it is dug deeper in stages.