Reactive soils and the role of screw piles.
What are reactive soils, and what measures can be created to overcome them?
Reactive soil, or expansive soils are types of soil that change significantly in volume as the moisture content varies. When soil absorbs water, the soil expands causing a phenomenon called Heave to structures founded in reactive soil. Essentially pushing structures such as concrete slabs up when reactive soils are wet and receding below the concrete slab when the soil dries. Usually caused by changes in the seasons and now amplified by weather systems such as El Nino, La Nina and the Indian Ocean Dipole. Reactive soils present a challenge for designer’s builders and owners. Screw piling presents us with an economical solution to the confronts of reactive soils.
Typical types of reactive soils
Clay: High clay content is the primary characteristic of reactive soil. Clays absorb high amounts of moisture, causing a considerable amount of volume expansion.
Silt: can also exhibit reactive properties, although to a lesser extent than clay.
How do reactive soils affect structures?
When foundations are founded on or into reactive soils. The load path from the building structure to its foundation expands and contracts. The movement of the building structure from its foundation is often uneven and can cause considerable asset damage.
Methods to combat reactive soils using a Geotechnical report.
Establishing the depth of reactive soils is the first step to designing a suitable foundation for a structure. A Geotechnical report (soil report) is used by an engineer to determine a solution for reactive soils. The Geotechnical report shows the type, depth and moisture content of soils below the ground surface. Often combined with local knowledge, a site specific geotechnical report aids the engineer at the design stage of the project. The appropriate foundation depth is typically at a depth below the ground surface, that has low moisture content and high load bearing capacity.
Why are screw piles Koble Constructions preferred choice for reactive soils
Steel screw piles are an excellent solution for reactive soils, particularly on challenging sites, as they can penetrate unstable, often waterlogged layers to reach solid founding material. Using screw piles is a reliable method that ensures strong foundations while preventing issues related to soil expansion and contraction. Koble Constructions prefer screw piling because it is the simplest, most cost-effective way to establish a foundation below the reactive soil line, providing fast reliable structural support while avoiding complications like soil collapse and the need for bulk concrete.
Koble Constructions. Reactive soil, screw pile foundation.