When should Density graphs be prepared?

Density graphs should be prepared as needed by hand plotting prior to construction because these graphs are essential for analyzing the characteristics of the soil and ensuring its suitability for the planned activities. Preparing density graphs before construction allows for the identification of any potential issues with soil compaction and stability, which is critical for the safety and longevity of the structure being built.

This practice helps contractors and engineers make informed decisions based on real-time data, ensuring that the ground conditions are within the desired specifications. Having these graphs available prior to construction enables proactive measures, which can prevent costly delays or structural failures later in the project.

The other options do not capture the proactive nature of preparing density graphs. They are more reactive or situational, which is not the best practice when it comes to construction planning and soil management.