Which method is most commonly used to assess soil bearing capacity?

The Standard Penetration Test (SPT) is widely recognized as the most common method for assessing soil bearing capacity. This test involves driving a sampler into the soil at the bottom of a borehole using a standardized weight and measuring the number of blows required to penetrate a certain depth. The results, specifically the number of blows for each foot of penetration, provide valuable insights into the soil's resistance and density, which can be directly correlated to its bearing capacity.

The practicality and established methodology of the SPT make it a preferred choice in both geotechnical engineering and construction projects. It generates consistent and reliable data that can be used in design calculations, which is crucial for determining whether the existing soil can support the intended load of structures.

While other methods, such as dynamic cone penetrometer tests or visual soil inspections, can provide useful information, they do not offer the same level of detailed quantitative data regarding soil strength and bearing capacity as the SPT does. Compaction tests, on the other hand, focus mainly on the soil's density rather than its bearing ability. Therefore, the SPT stands out as the most effective tool for evaluating soil bearing capacity in various construction contexts.