Soldier beams are H-piles which are driven at suitable spacing of 1.5 to 2.5 m. around the boundary of the proposed excavation

Fig-6.31 Soldier Beam

As the excavation proceeds, horizontal timber planks called lagging are placed between the soldier beams. When the excavation advances to the suitable depth, Wales and the struts are inserted. The lagging is properly wedged between piles flanges or behind thee back flange.