The correct answer is D. Unconfined compression test can be carried out on all types of soils.
A direct shear box test is a soil test that is used to determine the shear strength of a soil. The test is conducted by placing a soil sample in a box and applying a shear force to the sample. The shear strength of the soil is then calculated based on the amount of force required to cause the sample to fail.
A triaxial compression test is a soil test that is used to determine the strength and deformation characteristics of a soil. The test is conducted by placing a soil sample in a chamber and applying a confining pressure to the sample. The sample is then subjected to a deviator stress, which is the difference between the major and minor principal stresses. The strength and deformation characteristics of the soil are then calculated based on the stress-strain behavior of the sample.
Unconfined compression test is a soil test that is used to determine the unconfined compressive strength of a soil. The test is conducted by placing a soil sample in a cylindrical mold and applying a compressive load to the sample. The unconfined compressive strength of the soil is then calculated based on the load required to cause the sample to fail.
The incorrect statement is D. Unconfined compression test can be carried out on all types of soils. This is because unconfined compression test is not suitable for soils that are highly sensitive or that have a high water content.
Sensitivities soils are soils that have a large change in shear strength with small changes in effective stress. Highly sensitive soils can fail suddenly and catastrophically when subjected to even small loads. Soils with a high water content are also not suitable for unconfined compression test because the water can cause the soil to lose its strength.