Unconfined Compression Test

Unconfined compression Strength test or UCS test, is used to determine the unconfined compressive strength of a cohesive soil such as clay. Unconfined compressive strength is a measure of the maximum stress or load that a cohesive soil specimen can withstand in an unconfined state without any lateral support. It represents the soil’s inherent shear strength as well as load bearing capacity. This test also analyses the potential failure modes of a soil sample (shear failure or general failure) along with the maximum applied load at failure. Hence, the UCS value of a soil provides straightforward measure of the soil’s strength as well as potential requirement of additional confining structures.
Like consolidation test, UCS test can also be carried our disturbed as well as undisturbed sample. Disturbed samples are generally obtained through excavation, drilling, or other methods that causes disruption in soil structure. In most of the cases, undisturbed samples are preferred more for testing since it represents the soil’s natural state. However, there is potential difficulty in extracting undisturbed samples. In those cases, the test is carried out on disturbed samples.