Conventional Shoring

Basically, this consists of installing vertical steel soldier piles at predetermined intervals around the perimeter of the proposed excavation, and supporting them with a system of rakers, struts or tie-backs which bear against a horizontal beam or waler placed against the soldier piles at a predetermined depth up from the bottom of the excavation.

Soldier piles are normally placed in drilled holes, which extend to a predetermined depth below final excavation level. That bottom portion of the hole is filled with concrete to provide stability. The upper portion of the hole is filled with low strength concrete. As excavation proceeds in small stages wood lagging is installed to span horizontally between adjacent soldier piles so as to retain the vertical cut. It may be required to conduct backfilling and compacting the void space behind the lagging.

Conditions at some sites dictate soldier piles be driven to required depths below final excavation level. In this case H-Piles sometimes fitted with special points are installed. In many instances shoring is used as the outer form for placement of concrete basement walls.
For shallow excavations, which require shoring, the use of rakers, struts and tiebacks may be eliminated entirely by designing soldier piles as cantilever beams anchored below the excavation. Such a design is most convenient, however is limited by cost usually to excavations not exceeding 4 to 5 meters in depth.

Soldier pile and timber lagging shoring walls are the least expensive method of providing ground support.

Major disadvantages of this type of systems are:

1. Primarily limited to temporary construction.
2. Extensive dewatering required in high water table conditions.
3. Significant surface settlement can occur as a result of improper lagging installation.
4. Not as stiff as other shoring systems.