What does the cone penetrometer measure?

• A. Moisture content and density
• B. Soil temperature and pH
• C. Tip resistance and side friction
• D. Permeability and compressibility

Answer: (C)

The cone penetrometer is an instrument used primarily in geotechnical engineering to assess the properties of soil. Its main function is to measure tip resistance and side friction.

When the penetrometer is pushed into the ground, the cone-shaped tip encounters resistance from the soil. The resistance encountered at the tip provides valuable information about the soil's strength and density, which can be used for various engineering assessments, such as determining soil bearing capacity and identifying soil stratigraphy. The side friction measured along the sleeve of the penetrometer is important for evaluating how well the soil holds the cone in place, further contributing to characterizing the material properties of the soil mass.

This measurement is crucial for understanding soil behavior under load and is widely used in site investigations for construction projects. The other options—moisture content and density, soil temperature and pH, and permeability and compressibility—are related to different testing methodologies and do not directly pertain to the specific measurements taken using a cone penetrometer.