What is defined as any additional loading applied externally to the soil?

The term that refers to any additional loading applied externally to the soil is surcharge. Surcharge is commonly understood in geotechnical engineering as an extra load added to the ground surface, which affects the soil stresses beneath that surface. This can arise from various sources, such as construction materials, structures, or any other weight placed on the soil, leading to increased soil stress and potential consolidation.

Understanding surcharge is essential for predicting the behavior of soil under load, especially in the context of foundation design and earthwork projects. The effects of surcharge can influence settlement, stability, and overall performance of structures built on or near the affected soil. In design situations, engineers must consider the impact of surcharge on the existing soil conditions to ensure safety and functionality.

Active and passive earth pressures relate to the lateral pressures exerted by soil on retaining structures and are not defined as external loads. Excavation involves the removal of soil, which may create changes in stress distribution but is not an external load applied to soil. Thus, the term surcharge correctly captures the concept of additional loading applied externally to the soil.