Which condition contributes to the triggering of liquefaction?

Liquefaction typically occurs when a saturated, loose sand layer is subjected to transient stress, such as during an earthquake or other dynamic loading conditions. The phenomenon is characterized by an increase in pore water pressure within the soil, which reduces its effective stress and can lead to a loss of strength, causing the soil to behave like a liquid.

The condition that contributes to triggering liquefaction is the presence of light loads on a saturated sand layer. When the sand is saturated, it is already at a high moisture content, meaning that the grain-to-grain contact under normal loading conditions is diminished. Upon application of light loads, particularly dynamic ones, sufficient pore pressure can build up, leading to a state where the soil can no longer support the applied load and behaves in a liquid-like manner. This scenario is critical because it is not just the saturation of the soil, but the nature of the loading that can lead to liquefaction.

In contrast, high N-values in the soil indicate denser, more compacted soil conditions, which are less prone to liquefaction. Deep saturation without any load does not provide the conditions necessary for liquefaction to occur, as there is no dynamic or live load to trigger the pore pressure buildup. Lastly, high