During the liquefaction process, what happens to shear strength?

During the liquefaction process, the shear strength of the soil approaches zero. This phenomenon typically occurs in saturated soils during earthquake shaking or sudden loading, where the pore water pressures increase, effectively reducing the effective stress in the soil.

As the effective stress diminishes, the soil particles lose their frictional interlock and ability to support loads, leading to a significant reduction in shear strength. The result is that the soil behaves more like a fluid rather than a solid, which can result in substantial ground deformation and instability during seismic events. This understanding is critical in civil engineering for assessing the stability of structures and the design of foundations in areas prone to liquefaction.