What is the purpose of a cone penetration test (CPT)?

The purpose of a cone penetration test (CPT) is to evaluate subsurface soil stratigraphy and strength. In this test, a cone-shaped penetrometer is pushed into the ground at a controlled rate, and the resistance encountered is measured. This data allows engineers and geologists to determine the types of soil present and their respective strengths, which is crucial for foundation design, assessing earthwork stability, and understanding other geotechnical conditions. By analyzing the resistance values and the characteristics of the soil layers encountered, professionals can create a detailed profile of the subsurface conditions, which is invaluable for construction projects and geotechnical investigations.

Other options like measuring soil moisture content, assessing soil color, or determining thermal properties, do not relate to the primary function of the CPT, which focuses heavily on the mechanical properties and stratigraphy of subsurface soils.