Geotechnical talks

Soil liquefaction is the phenomenon when due to sudden load soil changes its solid state into liquefied state. When saturated soil (sand and silt) is subjected to earthquake its strength and stiffness is reduced. In saturated soil space between individual particles is completely filled up with water. When saturated soil is subjected to earthquake excess pore water pressure develops because of which soil particles readily moves and simultaneously it behaves like liquid and looses its stiffness. Due to this phenomenon soil looses its ability to support structures, can even lead to very gentle slope failure and even lead to soil boiling.

Mechanism which cause soil liquefaction:

Strain softening soil: Soil like loose sand is susceptible to liquefaction when either static or cyclic load is applied on it and it’s greater than its ultimate stress. In this type of situation flow liquefaction occurs.

Strain softening soil: Dense or moderately dense soil is susceptible to cyclic softening when cyclic undrained load is applied on it. This type of phenomenon leads to cyclic liquefaction.