Embed Size (px)
Citation preview
Liquefaction
Prepared by :
December 2012
Nariman Dehghani
Earthquake
An earthquake is the motion or trembling of the ground produced by sudden displacement of rock in the Earth's crust. Earthquakes result from crustal strain, volcanoes, landslides, and collapse of caverns.
The effects of earthquakes include, but are not limited to, the following:
Shaking and ground ruptureLandslidesFiresSoil liquefactionTsunamiFloodsHuman impacts
Earthquake Effects - Ground Shaking
Northridge, CA 1994
Earthquake Effects -
Ground Shaking
Northridge, CA 1994
Earthquake Effects - Ground Shaking
Loma Prieta, CA 1989
Earthquake Effects - Ground Shaking
Kobe, Japan 1995
Earthquake Effects - Ground Shaking
Kobe, Japan 1995
Earthquake Effects - Surface Faulting
Landers, CA 1992
Earthquake Effects - Liquefaction
Niigata, Japan 1964
Earthquake Effects - Landslides
Turn again Heights, Alaska,1964 (upper left inset);Santa Cruz Mtns, California , 1989
Earthquake Effects - Fires
Loma Prieta, CA 1989
Earthquake Effects - Tsunamis
1957 Aleutian Tsunami
Soil liquefaction describes a phenomenon whereby a saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid.
Liquefaction
Liquefaction occurrence:
Liquefaction is more likely to occur in loose to moderately saturated granular soils with poor drainage, such as silty sands or sands and gravels capped or containing seams of impermeable sediments.
Earthquake liquefaction:
The pressures generated during large earthquakes with many cycles of shaking can cause the liquefied sand and excess water to force its way to the ground surface from several meters below the ground.
Effects:
The effects of soil liquefaction on the built environment can be extremely damaging. Buildings whose foundations bear directly on sand which liquefies will experience a sudden loss of support, which will result in drastic and irregular
settlement of the building causing structural damage, including cracking of foundations and damage to the building structure itself, or may leave the structure unserviceable afterwards, even without structural damage.
Niigata Japan 1964
Loma Prieta 1989
Kobe Japan 1995
Niigata 1964
