Foundations in Floodplains

Floodplains are areas subject to periodic flooding due to floods, rain, or proximity to bodies of water. Construction in such areas requires a special approach to foundation selection and installation to ensure the durability and safety of the structure. In this article, we will discuss what floodplains are, what type of foundation is most suitable for such conditions, the process of preparing and installing piles, and the criteria for selecting piles for floodplains.

What are floodplains?

Floodplains are lands where water periodically accumulates as a result of various natural and climatic phenomena. Causes of flooding may include:

• River and lake overflows

• Intense and prolonged rainfall

• High groundwater levels

• Poor drainage or low soil permeability

Foundations in floodplains can face a number of specific challenges that can significantly impact the durability and stability of the structure. Here are the main problems that may arise:

1. Soil subsidence. Flooding can lead to erosion and weakening of the soil, which causes subsidence.

• Unevenness of the foundation and the structure itself

• Cracks in the walls and deformation of building elements

• Uneven distribution of loads on the foundation

2. Soil erosion. Constant exposure to water can erode the soil around and under the foundation, which contributes to:

• Reduction of the soil's bearing capacity

• Landslides and foundation failure

• Increased risk of structural collapse

3. Corrosion and deterioration of materials. A humid environment promotes accelerated deterioration of metal foundation elements, leading to:

• Corrosion of steel piles and reinforcement

• Reduced foundation strength and durability

• The need for frequent repairs and replacement of damaged elements

4. Rising groundwater. Rising groundwater levels can result in water coming into direct contact with the foundation, leading to:

• Dampness and mold in basements and crawl spaces

• Flooding of basements and damage to interior finishes

• Increased humidity in the home, which can negatively impact the health of residents

5. Soil heaving. When water in the ground freezes, it expands, causing heaving, which leads to:

• Foundation heaving and deformation

• Cracks and damage in building structures

• Inability to use standard construction technologies

6. Drainage problems. Flooded areas often have poor natural drainage, which exacerbates soil problems due to:

• Water accumulation around and under the foundation

• Wetting and damage to building materials

• The need to install complex and expensive drainage systems

7. Uneven load distribution. Soil in flooded areas can have uneven density and bearing capacity, which leads to:

• Uneven settlement of various foundation components

• Deformations and distortions of the structure

• Increased wear and damage to building elements

Therefore, it is important to select the appropriate foundation type that can withstand these conditions.

What type of foundation is needed for a flooded area?

Pile foundations are the most suitable for flooded areas, as they provide stability and protection from water damage. Screw piles are one of the best solutions because they:

• Provide good stability in weak and water-saturated soils

• Can be installed at various depths, reaching dense soil layers

• Resistant to corrosion and other effects of a humid environment

How to Choose a Pile for a Floodable Area

When choosing piles for a flooded area, consider several key factors:

Material

• Galvanized steel: Provides high corrosion resistance, which is especially important in high-humidity conditions. • Stainless steel: Another option with high corrosion resistance, but a more expensive option.

Diameter and Length

• Diameter: Choose piles with a larger diameter to increase load-bearing capacity.

• Length: Piles should be long enough to reach dense soil layers. Conduct a geological survey to determine the required length.

Blades

• Wide blades: Provide better stability in soft and water-saturated soils.

• Multi-stage blades: Can be useful for improving traction.

Construction in flooded areas requires special attention to the selection and installation of the foundation. Helical piles are the optimal solution, ensuring the reliability and stability of the structure in high-moisture conditions. By following recommendations for site preparation, pile selection, and installation, you can create a strong and durable foundation for your building.