What are Controlled Modulus Columns?

Technical Characteristics of CMC

The technical specifications of CMCs are centred around their deep reach and effective size for load-bearing:

• Depth: CMCs can reach depths of up to 50 meters for soil treatment.
• Diameter: The elements typically range from 280mm to 500mm in diameter, which ensures they are highly effective in load distribution.

How Things Operate at the Construction Site?

The functionality of CMCs can be understood through the following five steps:

Displacement of Soil: The augers move the soil laterally, consolidating it beneath the CMC for better load support.

Densification: This process compacts the soil, increasing its ability to carry heavy loads from the structure above.

Reinforcement: During installation, the ground is compacted and strengthened, improving its properties to create a composite system with the CMCs.

Distribution of Load: Once installed, the load from the structure is transferred to both the CMCs and the soil beneath them. The stiffer the soil, the more load it bears.

Load Transfer Platform (LTP): A layer of broken stone, known as the Load Transfer Platform, is usually added on top of the CMCs to help distribute loads uniformly throughout the platform.

Advantages of Controlled Modulus Columns

The Controlled Modulus Column (CMC) method offers several advantages over traditional piling methods:

• Economically Viable: CMCs are more financially viable than traditional piling, as they use fewer materials and require a smaller workforce.
• Time Efficiency: The installation procedure is quicker, minimising overall construction schedules and speeding up project completion.
• Minimum Ecological Impact: CMCs are eco-friendly, producing minimum land disturbance and conserving the environmental surroundings.
• Adaptability: CMCs are convenient for different building projects and can be used in various types of soil and ecological conditions.

Disadvantages of Controlled Modulus Columns

In spite of the numerous advantages, CMCs accompany specific disadvantages that must be taken into account:

• Limited use: CMCs are perfect for loose, granular, or soft clayey soils but might not work well in highly cohesive soils with high plasticity or places with a high water table.
• Construction constraints: Installing CMCs requires specific tools and a trained workforce, which might not always be easily accessible, especially in urban or remote places where such resources are in short supply.
• Long-term performance: While CMCs elevate the land’s load-bearing capability, they might be impacted by persistent problems like settlement, consolidation, and differential movement if they are not meticulously designed and checked.
• Possibility of failure: CMCs have been unsuccessful in certain circumstances because of improper placement or design faults. Factors leading to failure include ineffective reinforcement, unsuitable material choices, and unfriendly soil conditions.