Why is soil liquefaction a major structural concern for offshore platforms?

Soil liquefaction is a major structural concern for offshore platforms because it can significantly reduce the bearing capacity and shear strength of the seabed soil, leading to platform settlement, instability, and potentially catastrophic failure. Soil liquefaction is a phenomenon in which saturated, loose soil loses its strength and stiffness in response to an applied stress, usually caused by seismic activity or wave loading. During liquefaction, the effective stress in the soil is reduced to near zero, causing the soil to behave like a liquid. Offshore platforms rely on the seabed soil to provide support and resistance to overturning forces. If the soil liquefies, the platform can lose its support and settle, tilt, or even collapse. The reduced shear strength can also make the platform more vulnerable to lateral loads from waves and currents. Areas prone to earthquakes or severe storm waves are particularly susceptible to liquefaction. For example, during an earthquake, the seabed soil around the foundations of an offshore platform can liquefy, causing the platform to sink or tilt, potentially leading to structural damage and loss of functionality.