Consolidation Test

Consolidation refers to process by which soil undergo deformation and settlement under applied loads over time. This deformation is due to rearrangement of soil particles after the expulsion of water present in the void spaces after the application of load. Hence, it is important to assess the consolidation properties of soil and check its probable settlement behaviour before the construction of any superstructures. Consolidation test, also known as oedometer test is thus a laboratory test used to determine the consolidation properties of soil which helps to predict the settlement behavior, assess potential risk and design the structures that can accommodate the expected settlements ensuring the long-term stability. Important parameters such as coefficient of consolidation and compression index are determined for analyzing settlement behavior.
Generally, undisturbed samples are generally preferred for consolidation testing as it provides overview of soil’s natural behavior. However, obtaining undisturbed samples can be challenges depending on the existing ground conditions and soil types. In such case, disturbed sample may be used. The results obtained for consolidation test on disturbed sample gives more accurate representation of soil’s true compressibility and settlement behavior.
Also, cohesive soil such as clay exhibit unique consolidation characteristics due to their low permeability and high compressibility. Hence, for clayey soils, careful handling with minimum disturbance is required for sampling.