Soldier piers are a type of cantilever support, using singular bored piles installed at optimal distances from one another, which may be given further lateral support with additional anchors or bracing, to provide an effective retaining wall solution.
Soldier piles can be used for temporary shoring or for permanent walls. When used as part of a piering system, soldier piling is ideal for use in piled walls in basement areas, as the piles may be designed to accommodate load points for the final structure (which can result in substantially longer piles under perimeter columns).
This method of piering is often used where ground conditions are generally cohesive soils, rock, or clay. Soldier piers are often the ideal shoring option for low-strength rock and clay soil profiles, where other options – such as lightweight sheet piling – often prove to be impractical and inefficient.
Bored piles are not suited to ground conditions where soil has a high-water content, or sites where the removal of excavated materials may be expensive or complicated – such as where the spoils to be disposed of are contaminated by substances such as acid sulphates or asbestos.
Soldier piers can be installed in much the same way as bored piers, with the use of regular bored piling techniques. The holes, or piles, are constructed by repeatedly drilling, then withdrawing the drill to remove ground material from the pile, until the required depth is reached.
Excavated ground materials are removed from the drilled shaft using purpose-designed drilling tools, including rock and soil augers, core barrels and clean-out buckets. Once drilling has been completed, the drilled shaft is cleaned and a steel reinforcement cage is placed in situ, then concrete is poured into the shaft. A plunger tube is used for concreting in the presence of water, to avoid segregation of the concrete (known as the tremie pipe technique). For more information on bored piles and how they are constructed click here.
In accordance with an engineered design plan, a modern drill rig is used to bore holes of the required diameter and depth around the perimeter of the proposed excavation site. Soldier piles are typically drilled and installed at between 900mm and 3.0m (OR 0.9m and 3.0m, OR 900mm and 3000mm) apart. The resultant, reinforced bored piles are known as ‘soldiers’.
Once soldier piles have been installed, a capping system is constructed for the piles and the gap between the piles is infilled – either by shotcrete panels, precast planks, or timber sleepers. This infilling provides the lagging between the piles, which transfers lateral loads into the soldier piering system.
Soldier piles can be drilled to the largest possible pile diameter. As soldier piering specialists we consult with engineers to design the best piling and piering solution for each site, or work to already-developed engineer-designed plans. For more information, contact the piling experts at Solmer Civil on 0418 497921