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- Soil liquefaction describes the behavior of soils that, when loaded, suddenly suffer a transition from a solid state to a liquefied state, or having the consistency of a heavy liquid. 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 . During loading, usually cyclic undrained loading, e.g. earthquake loading, loose sands tend to decrease in volume, which produces an increase in their porewater pressures and consequently a decrease in shear strength, i.e. reduction in effective stress. 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 metres thick, and saturated with water. Such deposits are often found along riverbeds, beaches, dunes, and areas where windblown silt and sand have accumulated. Some examples of liquefaction include quicksand, quick clay, turbidity currents, and earthquake liquefaction. 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 shear 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 . 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 . Although the effects of liquefaction have been long understood, it was more thoroughly brought to the attention of engineers and seismologists in the 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.
- Bodenverflüssigung kann infolge starker Erschütterungen wasserhaltiger, sandiger Bodenschichten durch ein Erdbeben stattfinden. Besonders feinsandige Schichten mit geringer Wasserpermeabilität (Durchlässigkeit) sind gefährdet. Dabei wird ein nach allen Seiten sich fortpflanzender Druck (dynamische Belastung) auf das nicht kompressible Wasser zwischen den Sandkörnern ausgeübt, die bis dahin ein festes Gefüge aufwiesen. Ein Strömungsdruckgefälle, auch Porenwasserüberdruck genannt, baut sich in der Sandschicht auf. Dabei wird das Korngefüge verdichtet und verliert seine Scherfestigkeit, die Sandschicht verflüssigt sich zu einem Sand-Wasser-Brei, Bereiche des Untergrundes können dann herausgepresst werden. Die gesamte Untergrundschicht wird somit instabil, darauf errichtete Gebäude versinken. Ein harmloses Experiment kann man im Watt oder am nassen Sandstrand durchführen, wenn der nasse Sand beim Auftreten um den Fuß hervorquillt. Siehe auch: Solifluktion, Nichtnewtonsches Fluid, Treibsand
- Maaperän nesteytymisellä kuvataan prosessia, jossa maaperä paineen alaisena, yhtäkkiä muuttuu kiinteästä raskaan nesteen kaltaiseksi. Ilmiö esiintyy eleensä irtonaisessa ja karkeassa maaperässä, josta vesi ei pääse virtaamaan pois. Veden ja paineen yhteisvaikutuksesta maaperän tiheys pienenee. Juoksuhiekka on esimerkki maaperän nesteytymisestä.
- La liquefazione del suolo è il comportamento dei suoli che, a causa di un aumento della pressione interstiziale, passano improvvisamente da uno stato solido a uno fluido, o con la consistenza di un liquido pesante. La liquefazione avviene più frequentemente in depositi sabbiosi e/o sabbioso limosi sciolti, a granulometria uniforme, normalmente consolidati e saturi. . Durante la fase di carico, le sollecitazioni indotte nel terreno, quali possono essere quelle derivanti da un evento sismico, possono causare un aumento delle pressioni interstiziali fino ad eguagliare la tensione soprastante. Viene così annullata la resistenza al taglio del terreno secondo il principio delle pressioni efficaci di Terzaghi, e si assiste così a un fenomeno di fluidificazione del suolo. In pratica, si può osservare che gli edifici costruiti al di sopra di un terreno soggetto a tale fenomeno si trovano come a galleggiare su di esso, in quanto il terreno non è più in grado di opporre resistenza alla spinta proveniente dall'alto. I depositi più soggetti a liquefazione sono giovani, dell'Olocene, dunque formatisi negli ultimi 10 000 anni, quali terreni sabbiosi o limosi (con dimensioni dei granuli simile ai terreni sabbiosi e con una distribuzione degli stessi omogenea) in letti con diversi metri di spessore, in condizioni sature. Questi depositi possono trovarsi lungo letti di un fiume, spiaggie, dune e altre aree dove il vento ha accumulato fini sedimenti o sabbie. Fenomeni di liquefazione sono le sabbie mobili, quick clay, correnti torbide e liquefazioni da terremoti. 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 shear 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 . 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 . 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.
- 液状化現象（えきじょうかげんしょう）とは、地震の際に地下水位の高い砂地盤が、振動により液体状になる現象。これにより比重の大きい構造物が埋もれ、倒れたり、地中の比重の軽い構造物（下水管等）が浮き上がったりする。単に液状化（えきじょうか、liquefaction）ともいう。
- A liquefação do solo descreve o comportamento de solos que, quando carregados, repentinamente sofrem uma transição de um estado sólido para um estado líquido, ou ficam com a consistência de um líquido grosso. A liquefação é mais ocorrente no desprendimento para moderar solos granulados saturados com drenagem pobre, como em areias finas ou areia e cascalho ou contendo fendas de sedimentos impermeáveis. http://www. ce. washington. edu/~liquefaction/html/main. html http://www. pnsn. org/SEIS/EQ_Special/WEBDIR_01022818543p/quakestory. html
- Файл:Chuetsu earthquake-earthquake liquefaction1. jpg Канализационный люк всплыл из-за разжижения грунта Разжижение грунтов — процесс, вследствие которого грунт ведёт себя не как твёрдое тело, а как плотная жидкость. Разжижение более характерно для насыщенных влагой сыпучих грунтов, таких как илистые пески или пески, содержащие прослойки непроницаемых для воды отложений. Породы, наиболее подверженные разжижению, относительно молоды, это пески и илы с частицами одинакового размера, слоем не менее метра и насыщенные водой. Такие породы часто находятся вдоль русел рек, у берегов, там, где накопился лёсс и песок. Некоторые примеры разжижения: плывун, плывунная глина, мутьевой поток и сейсмическое разжижение. Разжижение грунта может произойти во время землетрясения, потому что при прохождении сейсмической волны частицы грунта начинают колебаться с разными скоростями и часть контактов между ними разрывается, в результате грунт может стать водой с взвешенными в ней песчинками. Вода стремится отжаться, но прежде чем грунт вернётся к первоначальному состоянию, здания, стоящие на нём, могут быть разрушены. Сильнейшие разрушения, вызванные разжижением грунтов, произошли в 1964 году: 27 марта у берегов Аляски близ Анкориджа и 16 июня в Ниигате.
- 土壤液化是地震工程的一个术语，指在外力的作用下，原本是固态的土壤变成液态，或变成粘稠的流质。土壤液化主要出现在分布深度较浅，饱和的疏松细砂、粉土质砂或粘土，且其底部排水较差。通常在外力反复震荡下（如地震），松散的土壤因受到压缩，内部空隙减小，导致空隙内水压升高，当水压升高至超过土壤内承受的外部压力时，加上水分不能从地底排出，就会产生土壤液化。 最容易发生的液化的土壤是年代比较轻（冰河时期，近一万年）的细沙，或颗粒相当且排列整齐的泥土中，地层只有数尺厚，富含水分。这样的地形通常可以在河岸、海岸或因风力而堆积而成的沙丘中找到。土壤液化的例子包括流沙、流粘土、浊流和地震液化。
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- Soil liquefaction describes the behavior of soils that, when loaded, suddenly suffer a transition from a solid state to a liquefied state, or having the consistency of a heavy liquid. 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 . During loading, usually cyclic undrained loading, e.g.
- Bodenverflüssigung kann infolge starker Erschütterungen wasserhaltiger, sandiger Bodenschichten durch ein Erdbeben stattfinden. Besonders feinsandige Schichten mit geringer Wasserpermeabilität (Durchlässigkeit) sind gefährdet. Dabei wird ein nach allen Seiten sich fortpflanzender Druck (dynamische Belastung) auf das nicht kompressible Wasser zwischen den Sandkörnern ausgeübt, die bis dahin ein festes Gefüge aufwiesen.
- Maaperän nesteytymisellä kuvataan prosessia, jossa maaperä paineen alaisena, yhtäkkiä muuttuu kiinteästä raskaan nesteen kaltaiseksi. Ilmiö esiintyy eleensä irtonaisessa ja karkeassa maaperässä, josta vesi ei pääse virtaamaan pois. Veden ja paineen yhteisvaikutuksesta maaperän tiheys pienenee. Juoksuhiekka on esimerkki maaperän nesteytymisestä.
- La liquefazione del suolo è il comportamento dei suoli che, a causa di un aumento della pressione interstiziale, passano improvvisamente da uno stato solido a uno fluido, o con la consistenza di un liquido pesante. La liquefazione avviene più frequentemente in depositi sabbiosi e/o sabbioso limosi sciolti, a granulometria uniforme, normalmente consolidati e saturi. .
- 液状化現象（えきじょうかげんしょう）とは、地震の際に地下水位の高い砂地盤が、振動により液体状になる現象。これにより比重の大きい構造物が埋もれ、倒れたり、地中の比重の軽い構造物（下水管等）が浮き上がったりする。単に液状化（えきじょうか、liquefaction）ともいう。
- A liquefação do solo descreve o comportamento de solos que, quando carregados, repentinamente sofrem uma transição de um estado sólido para um estado líquido, ou ficam com a consistência de um líquido grosso. A liquefação é mais ocorrente no desprendimento para moderar solos granulados saturados com drenagem pobre, como em areias finas ou areia e cascalho ou contendo fendas de sedimentos impermeáveis. http://www. ce. washington. edu/~liquefaction/html/main. html http://www. pnsn.
- Файл:Chuetsu earthquake-earthquake liquefaction1. jpg Канализационный люк всплыл из-за разжижения грунта Разжижение грунтов — процесс, вследствие которого грунт ведёт себя не как твёрдое тело, а как плотная жидкость.
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