Liquefaction
Definition
Loss of shear strength in saturated granular soil when earthquake-induced cyclic loading causes pore water pressure to equal the total stress, reducing effective stress to zero and making the soil behave like a liquid.
- Trigger
- Earthquake-induced cyclic loading
- Condition
- Saturated granular soil
- Mechanism
- Pore water pressure rises to equal total stress
- Effect
- Effective stress drops to zero, soil behaves as a liquid
Common questions
Why does liquefaction matter in a structural failure investigation?+
A foundation adequately designed for normal soil conditions can still fail if the ground beneath it liquefies during shaking, so investigators must assess soil saturation and grain characteristics, not just the structure itself.
What soil conditions make liquefaction more likely?+
Loose, saturated, fine to medium sand deposits close to the water table are most susceptible, while dense, well compacted or unsaturated soils resist the pore pressure buildup that drives liquefaction.
Related terms
- Bearing Capacity
- The maximum stress a soil or rock can sustain beneath a foundation without shear failure. Expressed as ultimate bearing capacity (at failure)...
- Cone Penetration Test (CPT)
- A continuous in-situ test pushing an instrumented cone through the soil and measuring tip resistance and sleeve friction. Provides a nearly continuous...
- Differential Settlement
- Non-uniform vertical movement of different parts of a foundation, distorting the structure it supports. More damaging than uniform settlement because it induces...
- Piping
- Internal erosion in an embankment or foundation in which seepage flow progressively removes fine particles along a concentrated flow path until a...
- Standard Penetration Test (SPT)
- An in-situ test measuring the number of blows to drive a split-spoon sampler 300 mm into the soil at a given depth....