Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sinking during earthquakes: Critical acceleration criteria control
  drained soil liquefaction   This article focuses on liquefaction of saturated granular soils, triggered
by earthquakes. Liquefaction is definedhere as the transition from a rigid
state, in which the granular soil layer supports structures placed on its
surface, toa fluidlike state, in which structures placed initially on the
surface sink to their isostatic depth within the granularlayer.We suggest a
simple theoretical model for soil liquefaction and show that buoyancy caused by
the presence ofwater inside a granular medium has a dramatic influence on the
stability of an intruder resting at the surface of themedium.We confirm this
hypothesis by comparison with laboratory experiments and discrete-element
numericalsimulations. The external excitation representing ground motion during
earthquakes is simulated via horizontalsinusoidal oscillations of controlled
frequency and amplitude. In the experiments, we use particles only
slightlydenser than water, which as predicted theoretically increases the
effect of liquefaction and allows clear depth-of-sinkingmeasurements. In the
simulations, a micromechanical model simulates grains using molecular
dynamicswith friction between neighbors. The effect of the fluid is captured by
taking into account buoyancy effects onthe grains when they are immersed. We
show that the motion of an intruder inside a granular medium is mainlydependent
on the peak acceleration of the ground motion and establish a phase diagram for
the conditions underwhich liquefaction happens, depending on the soil bulk
density, friction properties, presence of water, and peak acceleration of the
imposed large-scale soil vibrations.We establish that in liquefaction
conditions, most cases relaxtoward an equilibrium position following an
exponential in time.We also show that the equilibrium position itself,for most
liquefaction regimes, corresponds to the isostatic equilibrium of the intruder
inside a medium of effectivedensity. The characteristic time to relaxation is
shown to be essentially a function of the peak ground velocity.

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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: astro-ph
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga