Which soil type should not be assumed to have a presumptive load-bearing capacity for foundations?

Which soil type should not be assumed to have a presumptive load-bearing capacity for foundations?

• A. Organic silt
• B. Clean gravel
• C. Dense clay
• D. Course sand

Answer: (A)

Organic silt is recognized as a soil type that should not be assumed to have a presumptive load-bearing capacity for foundations due to its variable and often unpredictable nature. This type of soil contains organic matter, which can lead to significant changes in moisture content and density, resulting in instability. When organic silt is saturated, it can lose strength and undergo consolidation, leading to settlement issues for structures built on it. In contrast, other soil types like clean gravel, dense clay, and coarse sand generally exhibit more consistent load-bearing capacities. Clean gravel tends to have excellent drainage and stability, dense clay can support structures once its properties are understood, and coarse sand can provide good support due to its compact nature. Therefore, one must exercise caution with organic silt, ensuring thorough geotechnical evaluations are conducted before any construction to ascertain its suitability for load-bearing applications.

Organic silt is recognized as a soil type that should not be assumed to have a presumptive load-bearing capacity for foundations due to its variable and often unpredictable nature. This type of soil contains organic matter, which can lead to significant changes in moisture content and density, resulting in instability. When organic silt is saturated, it can lose strength and undergo consolidation, leading to settlement issues for structures built on it.

In contrast, other soil types like clean gravel, dense clay, and coarse sand generally exhibit more consistent load-bearing capacities. Clean gravel tends to have excellent drainage and stability, dense clay can support structures once its properties are understood, and coarse sand can provide good support due to its compact nature. Therefore, one must exercise caution with organic silt, ensuring thorough geotechnical evaluations are conducted before any construction to ascertain its suitability for load-bearing applications.