What factor should be considered when determining loading on soil layers?

When determining the loading on soil layers, it's crucial to focus on the layer with the smallest bearing value. This is because the bearing capacity of soil layers directly influences the overall stability and support that can be provided for structures.

The smallest bearing value indicates the layer that is likely to fail first under a given load; therefore, assessing the properties of this layer becomes essential. If a load exceeds the bearing capacity of the weaker layer, it may lead to settlement, structural damage, or even catastrophic failure.

Considering only the surface layer or treating all layers equally overlooks the complexities of soil mechanics, where different layers possess varying soil characteristics and bearing values. Additionally, focusing on the layer with the largest bearing value may lead to an underestimation of the potential weaknesses in the foundation's ability to safely support the imposed loads. Thus, understanding and applying the condition of the weakest layer ensures that the design effectively accommodates the loads generated by the structure.