Settlement data obtained from which laboratory test?

Settlement data obtained from which laboratory test?

• A. Consolidation
• B. Permeability
• C. Direct shear
• D. Compaction

Answer: (A)

Settlement data come from a one-dimensional consolidation test (often called the oedometer test). In this test, a soil specimen is placed in a rigid cell, a vertical load is applied in steps, and the vertical deformation (settlement) is recorded over time as pore water escapes. This setup directly captures how much and how quickly a soil settles under load, including the immediate elastic settlement and the longer-term primary consolidation settlement due to pore-pressure dissipation. From the test, you can derive key parameters that describe settlement behavior, such as the coefficient of consolidation, compression index, and recompression index, which are used to predict field settlement under various loading conditions. The other tests measure different properties: permeability focuses on how easily water flows through soil, direct shear assesses shear strength, and compaction determines maximum dry density and optimum moisture content—none of which provide the time-dependent settlement data that consolidation testing yields.

Settlement data come from a one-dimensional consolidation test (often called the oedometer test). In this test, a soil specimen is placed in a rigid cell, a vertical load is applied in steps, and the vertical deformation (settlement) is recorded over time as pore water escapes. This setup directly captures how much and how quickly a soil settles under load, including the immediate elastic settlement and the longer-term primary consolidation settlement due to pore-pressure dissipation. From the test, you can derive key parameters that describe settlement behavior, such as the coefficient of consolidation, compression index, and recompression index, which are used to predict field settlement under various loading conditions. The other tests measure different properties: permeability focuses on how easily water flows through soil, direct shear assesses shear strength, and compaction determines maximum dry density and optimum moisture content—none of which provide the time-dependent settlement data that consolidation testing yields.