Which method is often used to assess the load-bearing capacity of soil?

Subsurface exploration is the method typically employed to assess the load-bearing capacity of soil. This technique involves drilling or sampling the soil beneath the ground surface to obtain detailed information about its composition, structure, and condition. By analyzing the sampled soil, engineers can determine various physical properties, such as density, shear strength, and moisture content, which are critical for understanding how well the soil can support structures.

In contrast, visual inspection may provide some general indications of soil condition but lacks the depth and detail required for a comprehensive evaluation. Field surveying focuses more on measuring land features and elevations rather than directly assessing soil properties. Surface grading pertains to shaping the ground's surface and does not evaluate the underlying soil's load-bearing capabilities. Thus, subsurface exploration stands out as the most effective method for garnering insights into soil performance and suitability for construction purposes.