In urban construction where space is restricted and ground conditions vary, engineering techniques have evolved to meet these complex demands. One such technique is contiguous piling, a widely adopted method for earth retention and deep excavation support. This process involves placing concrete piles in close proximity to each other to form a continuous wall-like structure. The small gaps between the piles can be sealed using grout or sprayed concrete, depending on the requirement and water ingress levels. It is especially effective in projects where excavation needs to be done adjacent to existing structures or property boundaries, as it minimizes ground movement and supports lateral loads efficiently.
The technique is commonly used in basements, underpasses, and foundation construction for high-rise buildings. When it comes to high water tables, reinforcement and sealing methods are enhanced to maintain structural integrity. The cost-efficiency and speed of installation make this method a preferred choice in congested city environments. Unlike diaphragm walls or secant piling, this method offers a more economical and faster solution while still delivering structural support where needed.
Contiguous pile shoring is particularly advantageous for temporary works, where the goal is to retain soil safely during excavation without the need for permanent retaining structures. It allows for excavation to continue without interruption, enabling contractors to progress with substructure development more swiftly. This system works effectively in a wide range of soil types, although it is most suitable in stiff clay or dense granular soils where wall permeability is not a critical issue.
Its application is not limited to temporary support. In some cases, the piles are incorporated into the permanent structure by acting as foundation walls or load-bearing elements. The flexibility in design, compatibility with reinforcement, and adaptability to site-specific conditions make contiguous piles a vital tool in the construction engineer's toolkit. Advances in drilling technology and concrete mix designs have further improved the reliability and sustainability of this piling method.
Safety is another critical reason why contiguous piling remains popular. The method reduces the risk of soil collapse, provides safe access for workers, and helps in controlling groundwater intrusion. It is also an environmentally friendly solution since it produces less vibration and noise compared to other shoring techniques, making it ideal for inner-city developments or sensitive areas.
