Is P-Wave Velocity an Indicator of Saturation in Sand with Viscous Pore Fluid?

Naesgaard, Ernest; Byrne, Peter; Wijewickreme, Dharma

doi:10.1061/(asce)1532-3641(2007)7:6(437)

Cited by 33 publications

(14 citation statements)

References 9 publications

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“…The above observations concur with the case of non-homogeneous partial saturation as defined in Naesgaard et al (2007). Naesgaard et al (2007) proposed two types of saturation conditions known as homogeneous (HPS) and non-homogeneous (NHPS) partial saturation. The HPS condition is represented by the situation when air bubbles are small and scattered throughout the void spaces.…”

Section: Fig 531: Variation Of V P With Skempton's Pore-water Presssupporting

confidence: 83%

“…On the other hand, the NHPS condition is represented by the occurrence of a few large air bubbles in localised area. Numerical simulation performed by Naesgaard et al (2007) shows that during HPS, air bubbles dispersed within the void spaces give rise to a homogenous fluid stiffness resulting in V p to be a function of B-value. However, HPS only exists in a theoretical situation.…”

Section: Fig 531: Variation Of V P With Skempton's Pore-water Pressmentioning

confidence: 99%

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Properties of soils using laboratory seismic methods and numerical modelling

Cheng¹

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CHAPTER 4: Finite Element Modelling 4.1 Outline and Purpose 4.2 Introduction to LS-DYNA 4.3 Calibration for stiffness response 4.3.1 The Timoshenko beam effect 4.3.2 Verification of the finite element model 102 4.3.3 Finite element simulation program 104 4.3.4 Correction factor for the Timoshenko beam effect 105 4.3.5 Validation of correction factor χ m 108 4.4 Calibration for damping response 114 4.4.1 The Viscoelastic material model 114 4.4.2 Input Parameters for Viscoelastic Model 118 4.4.3 Finite element simulation program 120 4.4.4 Calibration of viscoelastic model using simulated resonant column test 122 4.4.5 Wave Propagation in a semi-infinite medium 125 4.5 Simulations for the Verification of the Hilbert Transform Method 128

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Section: Fig 531: Variation Of V P With Skempton's Pore-water Presssupporting

confidence: 83%

Section: Fig 531: Variation Of V P With Skempton's Pore-water Pressmentioning

confidence: 99%

Properties of soils using laboratory seismic methods and numerical modelling

Cheng¹

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“…Even a very slight decrease in the degree of saturation of a soil, S r , from the state of full saturation leads to a very significant reduction in the P-wave velocity (Kokusho, 2000;Ishihara et al, 2001;Tsukamoto et al, 2002;Yang, 2002;Emerson & Foray, 2006;Naesgaard et al, 2007). Significant differences arise between the behaviour of unsaturated, dry and fully saturated soils, primarily as a result of the influence of the capillarity in partly saturated soils.…”

Section: Introductionmentioning

confidence: 99%

Dynamic properties of sand from dry to fully saturated states

Kumar¹,

Madhusudhan²

2012

Géotechnique

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By using bender and extender elements test, the velocities of the primary and shear waves, V p and V s respectively, were measured for a sandy material by gradually varying the degree of saturation, S r , between the dry and fully saturated states. The effect on the results of varying the relative density and effective confining pressure was also studied. The measurements clearly reveal that for a certain optimum S r , which is around 0 . 7-0 . 9% for the chosen sand, the value of the shear modulus G reaches a maximum value, whereas the corresponding Poisson's ratio í attains a minimum value. The values of the shear modulus corresponding to S r % 0% and S r 100% tend towards the same value. For values of Skempton's B parameter greater than 0 . 99, the values of V p and í rise very sharply to those of water. The predictions from Biot's theory with respect to the variation of V p with S r match well with the measured experimental data.En utilisant des essais sur des éléments de cambrage et d'extension, on a mesuré les vitesses V p et V s , des ondes primaires et de cisaillement respectivement pour une matière sableuse, en faisant varier progressivement le degré de saturation (S r ) entre les états sec et entièrement saturé. On a également examiné l'effet de la variation de la densité relative et de la contrainte de confinement utile sur les résultats. Ces mesures révèlent clairement que pour un S r optimum, relevé aux alentours de 0,7 à 0,9% pour le sable choisi, le module de cisaillement (G) atteint une valeur maximale, tandis que le ratio de Poisson (í) atteint une valeur minimale. Les valeurs du module de cisaillement correspondant à S r % 0% et S r 100% présentent une tendance vers la même valeur. Pour des valeurs du paramètre B de Skempton supérieures à 0,99, les valeurs V p et í augmentent considérablement par rapport à celles de l'eau. Les prédictions de la théorie de Biot relativement à la variation de V p en fonction de S r correspondent parfaitement aux données relevées expérimentalement.

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“…However, other research has shown that using the v p to determine fully saturated conditions is not reliable (Ishihara, Huang and Tsuchiya ; Tamura et al . ; Naesgaard, Byrne and Wijewckreme ). The results of the UNIT testing illustrate that while a v p ‐saturation relationship, equation , does exist, the material exhibits a sharp increase in v p with the degree of saturation between 20% and 40% with little change outside this range, irrespective of wetting or drying cycles, Fig.…”

Section: Resultsmentioning

confidence: 99%

The behaviour of near‐surface soils through ultrasonic near‐surface inundation testing

Taylor

Cunningham

Walker

et al. 2019

Near Surface Geophysics

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Seismometers installed within the upper metre of the subsurface can experience significant variability in signal propagation and attenuation properties of observed arrivals due to meteorological events. For example, during rain events, both the time and frequency representations of observed seismic waveforms can be significantly altered, complicating potential automatic signal processing efforts. Historically, a lack of laboratory equipment to explicitly investigate the effects of active inundation on seismic wave properties in the near surface prevented recreation of the observed phenomena in a controlled environment. Presented herein is a new flow chamber designed specifically for near‐surface seismic wave/fluid flow interaction phenomenology research, the ultrasonic near‐surface inundation testing device and new vp‐saturation and vs‐saturation relationships due to the effects of matric suction on the soil fabric.

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Is P-Wave Velocity an Indicator of Saturation in Sand with Viscous Pore Fluid?

Cited by 33 publications

References 9 publications

Properties of soils using laboratory seismic methods and numerical modelling

Properties of soils using laboratory seismic methods and numerical modelling

Dynamic properties of sand from dry to fully saturated states

The behaviour of near‐surface soils through ultrasonic near‐surface inundation testing

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