Which method can improve soft soils to reduce long-term settlement?

Which method can improve soft soils to reduce long-term settlement?

• A. Dynamic compaction
• B. Excavation and replacement
• C. Admixtures and reinforcement with geosynthetics
• D. Surface drainage

Answer: (C)

To improve soft soils and reduce long-term settlement, using admixtures and reinforcement with geosynthetics addresses the soil's inherent weaknesses effectively. Admixtures, such as cement or lime, can enhance the soil's physical properties by increasing strength and reducing plasticity. This chemical stabilization can help in binding the soil particles together, leading to reduced compressibility and improved load-bearing capacity. Additionally, incorporating geosynthetics—such as geogrids or geotextiles—provides additional structural support and helps distribute loads more evenly. The combination of these materials improves the soil’s mechanical behavior and increases the overall stability of the soil mass, which is crucial for long-term performance in construction projects. Dynamic compaction, while effective for increasing the density of granular soils and reducing voids, may not address the underlying issues with soft soils as effectively. Excavation and replacement can be costly and labor-intensive, and surface drainage, while important for managing water, does not inherently change the properties of the soil itself. Therefore, the method of using admixtures and geosynthetics is notably advantageous for long-term settlement reduction in soft soils.

To improve soft soils and reduce long-term settlement, using admixtures and reinforcement with geosynthetics addresses the soil's inherent weaknesses effectively. Admixtures, such as cement or lime, can enhance the soil's physical properties by increasing strength and reducing plasticity. This chemical stabilization can help in binding the soil particles together, leading to reduced compressibility and improved load-bearing capacity.

Additionally, incorporating geosynthetics—such as geogrids or geotextiles—provides additional structural support and helps distribute loads more evenly. The combination of these materials improves the soil’s mechanical behavior and increases the overall stability of the soil mass, which is crucial for long-term performance in construction projects.

Dynamic compaction, while effective for increasing the density of granular soils and reducing voids, may not address the underlying issues with soft soils as effectively. Excavation and replacement can be costly and labor-intensive, and surface drainage, while important for managing water, does not inherently change the properties of the soil itself. Therefore, the method of using admixtures and geosynthetics is notably advantageous for long-term settlement reduction in soft soils.