A mechanism to explain soil liquefaction environmental effects during an earthquake

Abstract

Soil liquefaction has potentially devastating consequences for infrastructures and endangers human lives. The mechanisms used to explain the above-ground environmental effects of soil liquefaction during and after an earthquake stops require a set of conditions seldom observed in situ (e.g. in the water degassing mechanism). The nature of the high-pressure heads observed remain unknown. Herein an alternative conceptual model is presented based on the pressure heads of the liquefied soil, water or slurry and the differences in density of the two fluids. Water or a slurry of low density, for example, from water springs flowing out of bedrock fissures, is a requirement of the model. A simulation of a simplified system shows that a pressure head of the slurry well over the required to reach the soil surface is obtained in most of the function's domain. The flow velocity at the surface will depend on the soil and water mixture ratio, which is expected to be correlated with the soil characteristics through the profile- the potential for the walls of the cracks to collapse. The inexistence of active water springs prevents the ejection of water mixtures at the soil surface. When saturated and permeable soil is shacked, as during an earthquake, the rearrangement of the solid particles leads to transient pore water pressure increase; however, the mean pressure head on a horizontal surface remains equal to the pressure head without shaking. This text discusses a mechanism to explain the above-ground environmental effects of soil liquefaction.