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SOIL LIQUEFACTION

DEFINITION:STILL GOING ON

‘Liquefaction is a phenomenon where in a mass of soil losses a large percentage of its shear resistance, when subjected to monotonic, cyclic, or shock loading, and flows in a manner resembling a liquid until the shear stresses acting on the mass are as low as the reduced shear resistance .’

Explanation of Liquefaction

Modes of Liquefaction

•Flow Liquefaction•Quasi Liquefaction•Sand Boiling

SAND BOILING• Sand boils can be a mechanism

contributing to liquefaction and levee failure during floods. 

• This effect is caused by a difference in pressure on two sides of a levee or dike, most likely during a flood.

• This process can result in internal erosion.

* Sand boils * lateral spreads * Loss of bearing capacity * ground settlement * failure of retaining wall* buoyant rise * ground oscillation* flow failures of slopes

Ground failures caused due to SOIL LIQUEFACTION

ADVERSE EFFECTS OF LIQUEFACTION

FLOW FAILURE

LATERAL SPREADING

GROUND OSCILLATION

EARTH QUAKE INDUCED LIQUEFACTION

DISASTERS DUE TO SOIL LIQUEFACTION

Counter measures against liquefaction

• Densification• Vibrofloatation• Blasting• Stabilization of Soils• Filtration (Drainage)• Lowering of ground water table• Application of dead weight• Mitigation of lateral flow by

providing baffle walls

Safety Precautions• Liquefaction mitigation by

improving the soil properties• > Vibro-Compaction• > Stone Columns• > Dynamic Compaction• > Compaction Grouting

Vibro-Compaction

Dynamic Compaction

Compaction Grouting

CONCLUSION• We studied soil liquefaction in detail with respect to

its importance, properties of soil, details of liquefaction, geotechnical study, evaluation techniques and remedial measures and concluded that liquefaction is very important phenomenon and it has not given that much important in India. The detailed study of liquefaction must be undertaken for Indian earthquake region and preventive measures must be conducted in liquefaction prone area so as to avoid the failure of structures during earthquake, So as to be safe against earthquake failure.