What kind of soils does the Constant Head Permeability Test assess?

The Constant Head Permeability Test is primarily used to assess granular soils, such as sands and gravels, due to their relatively high permeability. This test is suitable for soils with higher hydraulic conductivity, where water flows through the soil at a manageable rate.

The method involves setting up a constant head of water and measuring the flow rate through the soil sample over a specific period. Granular soils typically have larger pore spaces, allowing for this steady and relatively unimpeded flow, which makes the test efficient and effective for determining their permeability characteristics.

In contrast, fine-grained soils, like silts and clays, have much lower permeability and may not yield reliable results with this test due to their high resistance to water flow. The test can also lead to inaccurate interpretations for organic soils, which are influenced by different factors such as compressibility and moisture content, making the Constant Head Method unsuitable.

Thus, the assessment of permeability using the Constant Head test is specifically designed for granular soils, confirming that option B accurately reflects the primary application of this testing method.