Soil stabilization and ground foundation construction

Types of soils by composition and their bearing capacity

Soils with Organic Matter

These include peat, silt, and vegetative soils, which are loose and heterogeneous in composition at different depths. Similar to the top layer of fertile soil, such soils are unsuitable as foundations due to their significant and uneven compressibility. They are removed using machinery to a design depth, reaching mineralized layers.

Coarse-Fragment Soils
These consist of rock debris, primarily with particle sizes over 2 mm, such as pebbles, gravel, and crushed stone. They can serve as excellent foundations for construction.

Sandy Soils
Sandy soils are composed of quartz and other mineral particles approximately 0.1–0.5 mm in size. The larger and cleaner the sand, the greater load it can withstand. The properties of sandy soils can change significantly when waterlogged, resulting in a quicksand-like state.

• Coarse dense sand: 6 kg/cm²
• Medium dense sand: 5 kg/cm²
• Medium-sized sand with medium density: 4 kg/cm²
• Fine moist dense sand: 3 kg/cm²
• Fine moist sand with medium density: 2 kg/cm²

Rocky Soils
These include quartzites, sandstones, and granites, typically forming continuous masses. They are water-resistant, non-compressible, and provide reliable and strong foundations for buildings.

Loam and Sandy Loam
These are mixtures of clay, sand, and silt particles. Loams contain 10–30% clay particles, while sandy loams have 3–10%. Their properties place them between sandy and clay soils. These are the most common soils in the central regions of Russia.

• Dry dense sandy loam: 3 kg/cm²
• Wet plastic dense sandy loam: 2.5 kg/cm²
• Wet plastic sandy loam with medium density: 2 kg/cm²

Clay Soils
Clay is plastic and can be rolled into a ball; when pressed, its edges remain smooth. A clay strand maintains its integrity when bent into a ring. The bearing capacity of clay depends significantly on its moisture content:

• Dry dense clay: 6 kg/cm²
• Wet plastic dense clay: 4 kg/cm²
• Wet plastic clay with medium density: 1 kg/cm²

Quicksands
Quicksands are water-saturated variants of sandy loams and other fine-grained soils. They are characterized by mobility and can flow like a liquid. Quicksands are nearly unsuitable as foundations, though their properties can be modified using specific methods.

Fill Soils
These are formed from backfilled landfills and pits. Building on such artificial soils without proper reinforcement is hazardous.

The methods we use to stabilize soils make it possible to more than double the bearing capacity of soils. In any case, after our work we guarantee the design strength of the foundations for roads, platforms and parking lots, as well as for single-story pre-fabricated hangars and buildings.

Stages of ground foundation construction

1. Removing the topsoil

The first stage of soil foundation stabilization is removing the topsoil. Test pits are dug to determine the soil structure and check for existing utilities.

• The fertile topsoil layer (humus with turf) typically lacks sufficient load-bearing capacity. It is removed to the design depth to ensure foundation stability.
• Removed soil is stored in a designated area and can later be used for landscaping or site reclamation.
  This step eliminates organic components prone to decomposition. Layered backfill with mineral-rich soil ensures a stable ground foundation.

2. Installing drainage systems if necessary

In areas with high groundwater levels or marshy terrain, effective drainage is essential for stabilizing the ground foundation.
Drainage prevents water accumulation, erosion, and deformation of the foundation. Common drainage methods include:

• Drainage ditches: Simple and cost-effective solutions to channel surface water.
• Buried drainage pipes: Installed in areas with significant water inflow to provide continuous drainage. Pipes often discharge into wells, sometimes requiring automated pumps.
  Drainage is crucial for slopes and high-water table areas. Without proper drainage, the stability of road, parking, or site foundations may be severely compromised, especially on wet, unstable soils.

3. Soil backfill and compaction

After site preparation, we proceed with layered construction of the foundation:

• Delivery of materials: sand-gravel mix (SGM), sand, gravel.
• Layered placement of materials with mandatory compaction at each stage.
• Use of specialized machinery to achieve optimal density.
  This process forms a reliable base layer that distributes loads and prevents subsidence.

4. Grading and interlayer compaction: granular interlock

Grading involves filling voids between larger aggregate particles with finer materials to create a dense, stable soil structure.

• Sand over gravel: Fine sand fills gaps between large stones, resulting in a denser structure.
• Gravel over clay: Improves stability and reduces mobility of clay foundations.
  Grading minimizes voids, enhances load-bearing capacity, and improves foundation resilience.

5. Use of geomaterials for stabilization

Modern geomaterials like nonwoven textiles and geogrids significantly enhance the durability and stability of soil foundations for roads, parking lots, and sites:

• Nonwoven geotextile:
  • Prevents intermixing of foundation layers.
  • Provides shear strength.
  • Distributes loads evenly.
• Geogrids:
  • Three-dimensional structures of plastic strips anchored to the foundation. Cells of grids are filled with gravel or/and sand.
  • Reinforces weak soils and prevents erosion or layer displacement.
    Geomaterials are indispensable for challenging sites requiring maximum reliability and longevity. This approach creates durable parking areas that outperform reinforced concrete of similar thickness at a lower cost.

6. Clay soil stabilization using lime

For road construction on clay foundations, a specialized stabilization technique with lime is used:

• Principle: Lime reacts chemically with clay, reducing plasticity and increasing strength.
• Stages of lime treatment:
  • Spread the calculated amount of lime over the soil surface using slaked lime or quicklime with water.
  • Mix the clay and lime with specialized equipment.
  • Compact the mixture with rollers or tampers.
    Lime stabilization reduces clay mobility, making it suitable for a stable soil-based road.

Applications of soil foundation stabilization

Modern soil stabilization technologies are widely used in construction:

• Industrial and utility sites: Earth floors for warehouses or light structures.
• Parking lots and vehicle storage areas: High load-bearing capacity and effective drainage are critical.
• Access roads: To residential, commercial, or industrial buildings.
• Roads: For light to medium traffic loads.

We provide a complete cycle of works, from site preparation to the construction of reliable soil foundations. Contact us for high-quality and durable solutions!