Abstract: The present invention provides a method of constructing underground structural concrete walls, using pre-cast, preferably pre-stressed, concrete panels, including: (a) casting in place a pair of parallel, opposing, underground guide walls spaced a predetermined distance apart; (b) excavating a trench, using the guide walls to guide the excavation tool, the trench having a predetermined width substantially equal to the space between the guide walls; (c) pouring a footing at the base of the trench; and (d) lowering a pre-cast panel into the trench in a desired orientation relative to the trench walls.