How does liquefaction occur during an earthquake?

How does liquefaction occur during an earthquake?

Liquefaction during an earthquake refers to the phenomenon where the ground transforms into a liquid-like state due to the shaking of the earth or other dynamic loads. Liquefaction is commonly observed in loose, granular soils and can lead to significant damage.

Liquefaction occurs due to the combination of several factors. Firstly, the granular structure of the soil and the void spaces between particles allow for easy passage of water. During an earthquake, the compression and relaxation movements of the ground can cause these void spaces to become filled with water. This water reduces the friction between the particles and significantly decreases the bearing capacity of the soil.

Secondly, the increased water pressure resulting from the compression and relaxation of the ground during an earthquake strains the soil's ability to bear its own weight. The increased water pressure in the soil leads to a state where a portion of the soil has a high risk of liquefaction.

During the process of liquefaction, the soil's bearing capacity rapidly decreases, and the granular structure becomes disrupted. The soil begins to behave like a liquid, causing displacements, cracks, and settlements in the foundations of buildings or other structures.

The risk of liquefaction varies depending on factors such as the granular nature of the soil, water content, compressibility, and earthquake loads. Loose sands, gravels, or silts pose a higher risk of liquefaction.

To prevent or mitigate liquefaction, it is important to properly evaluate the soil and employ appropriate strengthening methods. Methods such as polyurethane resin injection can be an effective option to stabilize the soil. Additionally, proper foundation design, water drainage systems, and appropriate building materials play a significant role in reducing the risk of liquefaction.