What phenomenon occurs if water pressure matches soil weight causing the soil to act like a liquid?

When the water pressure within the soil pores increases to the point that it counteracts the weight of the soil, this results in a phenomenon known as liquefaction. During liquefaction, the effective stress within the soil decreases significantly, allowing the soil grains to lose contact with one another. This transformation can occur during seismic events, where vibrations disturb the soil structure and trigger this behavior.

Liquefaction is particularly significant in saturated, cohesionless soils, such as sand, where the water pressure can momentarily elevate as a result of dynamic loads, effectively turning the soil into a state that behaves similarly to a liquid. This can lead to extensive ground failures, loss of bearing capacity, and damage to structures built on or within such soils.

The other choices reflect different concepts in soil and geotechnical engineering, but they do not describe the specific condition of soil behaving like a liquid due to water pressure counteracting soil weight.