Compaction front and pore fluid pressurization in horizontally shaken drained granular layers.

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985858%3A_____%2F20%3A00524193" target="_blank" >RIV/67985858:_____/20:00524193 - isvavai.cz</a>

Výsledek na webu

<a href="http://hdl.handle.net/11104/0308904" target="_blank" >http://hdl.handle.net/11104/0308904</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevFluids.5.054301" target="_blank" >10.1103/PhysRevFluids.5.054301</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Compaction front and pore fluid pressurization in horizontally shaken drained granular layers.

Popis výsledku v původním jazyce

In many natural granular systems, the interstitial pores are filled with a fluid. Deformation of this two-phase system is complex, is highly coupled, and depends on the initialnand boundary conditions. Here we study granular compaction and fluid flow in a saturated, horizontally shaken, unconfined granular layer, where the fluid is free to flow in and out of the layer through the free upper surface during shaking (i.e., drained boundary condition). The geometry, boundary conditions, and parameters are chosen to resemble a shallow soil layer, subjected to horizontal cyclic acceleration simulating that of an earthquake. We develop a theory and conduct coupled discrete element and fluid numerical simulations. Theoretical and simulation results show that under drained conditions and above a critical acceleration, the grain layer compacts at a rate governed by the fluid flow parameters of permeability and viscosity and is independent of the shaking parameters of frequency and acceleration. A compaction front develops, swiping upward through the system. Above the front, compaction occurs and the fluid becomes pressurized. Pressure gradients drive fluid seepage upward and out of the compacting layer while supporting the granular skeleton. The rate of compaction and the interstitial fluid pressure gradient coevolve until fluid seepage forces balance solid contact forces and grain contacts disappear. As an outcome, the imposed shear waves are not transmitted and the region is liquefied. Below the compaction front (i.e., after its passage), the grains are well compacted, and shaking is transmitted upward. We conclude that the drained condition for the interstitial pore fluid is a critical ingredient for the formation of an upward-moving compaction front, which separates a granular region that exhibits a liquidlike rheology from a solidlike region.

Název v anglickém jazyce

Compaction front and pore fluid pressurization in horizontally shaken drained granular layers.

Popis výsledku anglicky

In many natural granular systems, the interstitial pores are filled with a fluid. Deformation of this two-phase system is complex, is highly coupled, and depends on the initialnand boundary conditions. Here we study granular compaction and fluid flow in a saturated, horizontally shaken, unconfined granular layer, where the fluid is free to flow in and out of the layer through the free upper surface during shaking (i.e., drained boundary condition). The geometry, boundary conditions, and parameters are chosen to resemble a shallow soil layer, subjected to horizontal cyclic acceleration simulating that of an earthquake. We develop a theory and conduct coupled discrete element and fluid numerical simulations. Theoretical and simulation results show that under drained conditions and above a critical acceleration, the grain layer compacts at a rate governed by the fluid flow parameters of permeability and viscosity and is independent of the shaking parameters of frequency and acceleration. A compaction front develops, swiping upward through the system. Above the front, compaction occurs and the fluid becomes pressurized. Pressure gradients drive fluid seepage upward and out of the compacting layer while supporting the granular skeleton. The rate of compaction and the interstitial fluid pressure gradient coevolve until fluid seepage forces balance solid contact forces and grain contacts disappear. As an outcome, the imposed shear waves are not transmitted and the region is liquefied. Below the compaction front (i.e., after its passage), the grains are well compacted, and shaking is transmitted upward. We conclude that the drained condition for the interstitial pore fluid is a critical ingredient for the formation of an upward-moving compaction front, which separates a granular region that exhibits a liquidlike rheology from a solidlike region.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GJ19-21114Y" target="_blank" >GJ19-21114Y: Mechanická teorie dynamicky aktivovaných zemětřesení</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review Fluids

ISSN

2469-990X

e-ISSN

—

Svazek periodika

5

Číslo periodika v rámci svazku

5

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

25

Strana od-do

054301

Kód UT WoS článku

000530033200003

EID výsledku v databázi Scopus

2-s2.0-85087865420