Soldier pile walls are mostly used for temporary excavations. The walls are built by installing vertical steel piles (usually H piles) at regular intervals (6? to 8? centers) along the retention wall line. The piles are installed from original grade before excavation. Excavation is usually dug in 4? lifts from the top down. 
As the excavation is advanced, lagging is inserted behind the front pile flanges. Lagging can be wood beams, steel or pre-cast panels or shotcrete. The lagging resists the load of the retained soil and transfers that load to the soldier piles.

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