Water Film in Liquefied Sand and Its Effect on Lateral Spread

Kokusho, Takuma

doi:10.1061/(asce)1090-0241(1999)125:10(817)

Cited by 189 publications

(65 citation statements)

References 4 publications

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“…Experiments for the situation in which a permeability barrier exists have also been conducted to study the formation process of water film and sand boils. In these studies, a one-dimensional tube test, to which an instant shock is applied (Kokusho 1999;Kokusho and Kojima 2002), or horizontal shake tables (Kokusho 1999;Yamaguchi et al 2008) were used. Experiments more closely simulating natural conditions have also shown that a variety of structures can form as a consequence of shaking (Moretti et al 1999).…”

Section: Manga and Wang 2007)mentioning

confidence: 99%

Shaking conditions required for flame structure formation in a water-immersed granular medium

Yasuda

Sumita

2014

Prog Earth Planet Sci

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Flame structures found in sedimentary rocks may have formed from liquefaction and gravitational instability when the sediments were still unconsolidated and were subject to shaking caused by earthquakes. However, the details of the process that leads to the formation of the flame structure, and the conditions required for the instability to initiate and grow remain unclear. Here, we conduct a series of small-scale laboratory experiments by vertically shaking a case containing a water-immersed layered granular medium. The upper granular layer consists of finer particles and forms a permeability barrier against the interstitial water which percolates upwards. We shake the case sinusoidally at different combinations of acceleration and frequency. We find that there is a critical acceleration above which the instability develops at the two-layer interface. This is because the upward percolating water temporarily accumulates beneath the permeability barrier. For larger acceleration, the instability grows faster and the plumes grow to form a flame structure, which however do not completely penetrate through the upper layer. We classify the experimental results according to the final amplitude of the instability and construct a regime diagram in the parameter space of acceleration and frequency. We find that above a critical acceleration, the instability grows and its amplitude increases. Moreover, we find that the critical acceleration is frequency dependent and is smallest at approximately 100 Hz. The frequency dependence of the critical acceleration can be interpreted from the combined conditions of energy and jerk (i.e., the time derivative of acceleration) of shaking, exceeding their respective critical values. These results suggest that flame structures observed in sedimentary rocks may be used to constrain the shaking conditions of past earthquakes.

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Section: Manga and Wang 2007)mentioning

confidence: 99%

Shaking conditions required for flame structure formation in a water-immersed granular medium

Yasuda

Sumita

2014

Prog Earth Planet Sci

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“…The assumption that soil liquefaction occurs under undrained conditions has led to extensive research into undrained tabletop experiments, such as triaxial and simple shear tests, with several methods suggested to overcome the small volume changes allowed by the compliance of the rubber membrane [4]. Although centrifuge and laboratory test data have long shown that water migration can occur [5,6], these situations have been treated as if they were exceptions to the normal situation of undrained pore pressure increase. However, given the thermodynamics of water pressure, the undrained assumption can lead to physically incorrect predictions.…”

Section: Introductionmentioning

confidence: 99%

“…One value of the model is that it predicts certain new features, such as large settlements together with bulk fluid flow to the surface in loose high permeability deposits, and also suggests a new mechanism of liquefaction potentially mediated by heating within silts even if the silt's initial density is such that sustained contractive loading does not occur. We compute solutions for several example scenarios that mimic the observed dynamics in tabletop [6,10] and centrifuge experiments [5].…”

Section: Introductionmentioning

confidence: 99%

Towards a complete model of soil liquefaction: the importance of fluid flow and grain motion

2014

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When loosely packed water-saturated granular soils, for example sands, are subjected to strong earthquake shaking, they may liquefy, causing large deformations with great destructive power. The phenomenon is quite general and occurs in any fluid-saturated granular material and is a consequence of the transfer of stress from inter-grain contacts to water pressure. In modern geotechnical practice, soil liquefaction is commonly considered to be an ‘undrained’ phenomenon; pressure is thought to be generated because earthquake deformations are too quick to allow fluid flow, which enables water depressurization. Here, we show via a first principles analysis that liquefaction is not a strictly undrained process; and, in fact, it is the interplay between grain rearrangement, fluid migration and changes in permeability, which causes the loss of strength observed in so many destructive earthquake events around the world. The results call into question many of the common laboratory and field methods of evaluating the liquefaction resistance of soil and indicate new directions for the field, laboratory and scale-model study of this important phenomenon.

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“…Water film is first observed in liquefied sand containing an impermeable seam accompanying slope failures in earthquakes (Seed 1987), and its formation in stratified sand has been revealed by shake table tests (Kokusho 1999) and centrifuge tests (Fiegel and Kutter 1994). Moreover, it is found that the film develops just beneath the fine sand layer and generally forms the sliding surface of slope.…”

Section: Introductionmentioning

confidence: 97%

Formation of layered fracture and outburst in stratums

Zhang

2014

Environ Earth Sci

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Layered fracture and outburst are two typical types of failures in a stratum that occur in many cases, such as liquefaction of sand, mining of coal, and dissociation of gas hydrate. The formation of both the failures is analyzed using the mathematical model based on the three-phase media. It is found that both failures occur once the pore pressure is high enough to cause the crashing and breakage of the skeleton. In other words, the formation conditions are related to the tensile strength of the stratum and the overburden. The fracture expands and shrinks along with the penetration and drainage of pore water and gas; outburst stops gradually as the energy dissipates in the stratum.

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Water Film in Liquefied Sand and Its Effect on Lateral Spread

Cited by 189 publications

References 4 publications

Shaking conditions required for flame structure formation in a water-immersed granular medium

Shaking conditions required for flame structure formation in a water-immersed granular medium

Towards a complete model of soil liquefaction: the importance of fluid flow and grain motion

Formation of layered fracture and outburst in stratums

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