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Soil liquefaction describes the behavior of water saturated soil when its behavior changes from that of a solid to that of a liquid. Some types of liquefaction include quicksand, quick clay, turbidity currents, and earthquake liquefaction. Loess field in Germany Surface-water-gley developed in glacial till, Northern Ireland Technically, soil forms the pedosphere: the interface between the lithosphere (rocky part of the planet) and the biosphere, atmosphere, and hydrosphere. ...
For other uses, see Solid (disambiguation). ...
A liquid will usually assume the shape of its container A liquid is one of the main states of matter. ...
This article or section does not adequately cite its references or sources. ...
Quick clay, also known as Leda Clay and Champlain Sea Clay in Canada, is a unique form of highly sensitive marine clay, with the tendency to change from a relatively stiff condition to a liquid mass when it is disturbed. ...
A turbidity current or density current is a current of of rapidly moving, sediment-laden water moving down a slope through air, water, or another fluid. ...
Earthquake liquefaction, often referred to simply as liquefaction, is the process by which saturated, unconsolidated soil or sand is converted into a suspension during an earthquake. ...
Loose saturated cohesionless soils, i.e. loose sands, can go from a solid state to have the consistency of a heavy liquid, or reach a liquefied state as a consequence of increasing porewater pressures, and thus decreasing effective stress, induced by their tendency to decrease in volume when subjected to cyclic undrained loading (e.g. earthquake loading). Liquefaction is more likely to occur in loose to moderate granular soils with poor drainage, such as silty sands or sands and gravels capped or containing seams of impermeable sediments (Youd et.al. 2001). Deposits most susceptible to liquefaction are young (Holocene-age, deposited within the last 10,000 years) sands and silts of similar grain size (well-sorted), in beds at least several feet thick, and saturated with water. Such deposits are often found along riverbeds, beaches, dunes, and areas where windblown silt (loess) and sand have accumulated.
Depending on the initial void ratio, the soil material can respond to loading either strain-softening or strain-hardening. Strain-softened soils, e.g. loose sands, can be triggered to collapse, either monotonically or cyclically, if the static shear stress is greater than the ultimate or steady-state strength of the soil. In this case flow liquefaction occurs, where the soil deforms at a low constant residual shear stress.
If the soil strain-hardens, e.g. moderately dense to dense sand, flow liquefaction will generally not occur. However, cyclic softening can occur due to cyclic undrained loading, e.g. earthquake loading. Deformation during cyclic loading will depend on the density of the soil, the magnitude and duration of the cyclic loading, and amount of shear stress reversal. If stress reversal occurs, the effective shear stress could reach zero, then cyclic liquefaction can take place. If stress reversal does not occur, zero effective stress is not possible to occur, then cyclic mobility takes place. (Robertson and Fear 1995)
The resistance of the cohesionless soil to liquefaction will depend on the density of the soil, confining stresses, soil structure (fabric, age and cementation), the magnitude and duration of the cyclic loading, and the extent to which shear stress reversal occurs (Robertson and Wride 1998).
Although the effects of liquefaction have been long understood, it was more thoroughly brought to the attention of engineers and seismologists in the 1964 Niigata, Japan and Alaska earthquakes. It was also a major factor in the destruction in San Francisco's Marina District during the 1989 Loma Prieta earthquake. Look up engineer in Wiktionary, the free dictionary. ...
Seismology (from the Greek seismos = earthquake and logos = word) is the scientific study of earthquakes and the movement of waves through the Earth. ...
Niigata ) is the capital and the most populous city of Niigata Prefecture, Japan. ...
Official language(s) English[1] Spoken language(s) English 85. ...
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This article needs to be cleaned up to conform to a higher standard of quality. ...
The Loma Prieta earthquake was a major earthquake affecting the greater San Francisco Bay Area of California. ...
Earthquake liquefaction
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Some effects of liquefaction during the 1964 Niigata earthquake.
Liquefaction allowed this sewer to float upward The shock or repeated shock of earthquake waves can cause water-saturated soil to rearrange itself in such a way that it essentially becomes a suspension of solids in the liquid. Heavy structures on such areas can suddenly sink or shift. Buried objects can shift and relatively low density objects can float to the surface. Earthquake liquefaction, often referred to simply as liquefaction, is the process by which saturated, unconsolidated soil or sand is converted into a suspension during an earthquake. ...
Niigata earthquake, from the Earthquake Engineering Research Center Library, University of California at Berkeley] This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...
Niigata earthquake, from the Earthquake Engineering Research Center Library, University of California at Berkeley] This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...
Photo by ja:利用者:Tubbi, broken asphalt road by Chuetsu Earthquake, 2004. ...
Photo by ja:利用者:Tubbi, broken asphalt road by Chuetsu Earthquake, 2004. ...
- "Often during earthquakes, fine-grained water-saturated sediments may lose their former strength and form into a thick mobile mudlike material. The process is called liquefaction. The liquefied sediment not only moves about beneath the surface but may also rise through fissures and “erupt” as mud boils and mud 'volcanoes.'"[1]
- "... the ground shaking reduces the strength of earth material on which heavy structures rest. Parts of many major cities, particularly port cities, have been built on naturally occurring bodies of soft, unconsolidated clay-rich sediment (such as the delta deposits of a river) or on filled areas in which large amounts of loose earth materials have been dumped to build up the land level. These water-saturated deposits often experience a change in property known as liquefaction when shaken by an earthquake. The material loses strength to the degree that it becomes a highly fluid mud, incapable of supporting buildings, which show severe tilting or collapse."[2]
This can be demonstrated on a small scale by saturating a bucket of sand with water; place a stone on the currently solid top of the sand, then repeatedly strike the side of the bucket with a hammer and watch the rock sink.
Studies of liquefaction features left by prehistoric earthquakes, called paleoliquefaction, can reveal a great deal of information about earthquakes that occurred before records were kept or accurate measurements could be taken. Paleoliquefaction is the term used to describe liquefaction features attributed to seismic events occuring before measurements or detailed records were kept of earthquakes. ...
Quicksand -
Quicksand forms when water saturates an area of loose sand and the ordinary sand is agitated. When the water trapped in the batch of sand cannot escape, it creates liquefied soil that can no longer support weight. Quicksand can be formed by standing or (upwards) flowing underground water (as from an underground spring), or by earthquakes. In the case of flowing underground water, the force of the water flow opposes the force of gravity, causing the granules of sand to be more buoyant. In the case of earthquakes, the shaking force can increase the pressure of shallow groundwater, liquefying sand and silt deposits. In both cases, the liquefied surface loses strength, causing buildings or other objects on that surface to sink or fall over. This article or section does not adequately cite its references or sources. ...
This article or section does not adequately cite its references or sources. ...
The saturated sediment may appear quite solid until a change in pressure or shock initiates the liquifaction causing the sand to form a suspension with each grain surrounded by a thin film of water. This cushioning gives quicksand, and other liquefied sediments, a spongy, fluidlike texture. Objects in the liquefied sand sink to the level at which the weight of the object is equal to the weight of the displaced sand/water mix and the object floats due to its buoyancy. In physics, buoyancy is the upward force on an object produced by the surrounding fluid (i. ...
Quick clay -
Quick clay, also known as Leda Clay in Canada, is a unique form of highly sensitive clay, with the tendency to change from a relatively stiff condition to a liquid mass when it is disturbed. Undisturbed quick clay resembles a water-saturated gel. When a block of clay is held in the hand and struck, however, it instantly turns into a flowing ooze, a process known as spontaneous liquefaction. Quick clay behaves this way because, although it is solid, it has a very high water content, up to 80%. The clay retains a solid structure despite the high water content, because surface tension holds water-coated flakes of clay together in a delicate structure. When the structure is broken by a shock, it reverts to a fluid state. Quick clay, also known as Leda Clay and Champlain Sea Clay in Canada, is a unique form of highly sensitive marine clay, with the tendency to change from a relatively stiff condition to a liquid mass when it is disturbed. ...
Quick clay, also known as Leda Clay and Champlain Sea Clay in Canada, is a unique form of highly sensitive marine clay, with the tendency to change from a relatively stiff condition to a liquid mass when it is disturbed. ...
The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ...
In optical filters and theatrical lighting a color gel is a transparent or translucent colored panel used to change the color of transmitted light. ...
Liquefaction may refer to: Soil liquefaction, the process by which sediments are converted into suspension, as in earthquake liquefaction, quicksand, quick clay, and turbidity currents. ...
In physics, surface tension is an effect within the surface layer of a liquid that causes that layer to behave as an elastic sheet. ...
Quick clay is only found in the northern countries such as Russia, Canada, Alaska, Norway, Sweden, and Finland, which were glaciated during the Pleistocene epoch. Official language(s) English[1] Spoken language(s) English 85. ...
The Pleistocene epoch is part of the geologic timescale, usually dated as 1. ...
Quick clay has been the underlying cause of many deadly landslides. In Canada alone, it has been associated with more than 250 mapped landslides. Some of these are ancient, and may have been triggered by earthquakes. [1] This entry refers to the geological term landslide. ...
Global earthquake epicenters, 1963–1998. ...
Turbidity currents -
Submarine landslides are turbidity currents and consist of water saturated sediments flowing downslope. An example occurred during the 1929 Grand Banks earthquake that struck the continental slope off the coast of Newfoundland. Minutes later, transatlantic telephone cables began breaking sequentially, farther and farther downslope, away from the epicenter. Twelve cables were snapped in a total of 28 places. Exact times and locations were recorded for each break. Investigators suggested that a 60-mile-per-hour (100 km/h) submarine landslide or turbidity current of water saturated sediments swept 400 miles (600 km) down the continental slope from the earthquake’s epicenter, snapping the cables as it passed.[3] A turbidity current or density current is a current of of rapidly moving, sediment-laden water moving down a slope through air, water, or another fluid. ...
A turbidity current or density current is a current of of rapidly moving, sediment-laden water moving down a slope through air, water, or another fluid. ...
The 1929 Grand Banks earthquake occured on November 18 of that year. ...
The continental shelf is an area of relatively shallow sea water that is found on the edge of each continent. ...
For other uses, see Newfoundland (disambiguation). ...
A transatlantic telephone cable is a submarine communications cable that carries telephone traffic under the Atlantic Ocean. ...
The epicenter is directly above the earthquakes focus. ...
The continental shelf is an area of relatively shallow sea water that is found on the edge of each continent. ...
See also Dry quicksand is loose sand whose bulk density is reduced by blowing air through it and which yields easily to weight or pressure. ...
The Liquid Limit, also known as the upper plastic limit, and the Atterberg limit, is the water content at which a soil changes from the liquid state to a plastic state. ...
A gaseous mud volcano The term mud volcano or mud dome is used to refer to formations created by geologically excreted liquids and gases, although there are several different processes which may cause such activity. ...
A sand volcano or sand blow is a cone of sand formed by the ejection of sand onto a surface from a central point. ...
Thixotropy is the property of some non-newtonian pseudoplastic fluids to show a time-dependent change in viscosity; the longer the fluid undergoes shear, the lower its viscosity. ...
References - ^ Harold L. Levin, Contemporary Physical Geology, 2nd edition (New York: Saunders College Publishing, 1986).
- ^ Arthur N. Strahler, Physical Geology (New York: Harper & Row, Publishers, 1981), p. 202.
- ^ Bruce C. Heezen and Maurice Ewing, “Turbidity Currents and Submarine Slumps, and the 1929 Grand Banks Earthquake,” American Journal of Science, Vol. 250, December 1952, pp. 849–873.
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