A novel bender/extender element for soil testing

Lings, ML; Greening, P. D.

doi:10.1680/geot.2001.51.8.713

Cited by 89 publications

(34 citation statements)

References 9 publications

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“…Bender=extender (BE) elements which are able to generate shear waves (S waves) and compression waves (P waves) were used in this research (Lings & Greening, 2001). Details of the installation of the bender elements using the cubical cell apparatus are described by O'Donovan et al (2014).…”

Section: Bender Element Testingmentioning

confidence: 99%

Quantitative assessment of the influence of surface roughness on soil stiffness

et al. 2015

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The nature of soil stiffness at small strains remains poorly understood. The relationship between soil stiffness (e.g. shear stiffness, G 0 ) and isotropic confining pressure ( p′) can be described using a power function with exponent (b), that is,, where A is a constant and p r is an arbitrary reference pressure. Experimentally determined values of b are usually around 0·5 and these are higher than the value of 0·33 that can be analytically determined using Hertzian theory. Hertzian theory considers contact between two smooth, elastic spheres; however, in reality, inter-particle contacts in soil are complex with particle shape and surface roughness affecting the interaction. Thus Hertzian theory is not directly applicable to predict real soil stiffness. It has, however, provided a useful basis to develop an analytical framework to consider the influence of particle surface roughness on small-strain soil stiffness. Here, earlier contributions using this framework are extended and improved by paying particular attention to roughness and the tangential contact stiffness. Stiffness values calculated using the newly derived analytical expressions were compared with the results of bender element tests on samples of borosilicate glass beads (ballotini) whose surface roughness was quantified using an optical interferometer. The analytical expression captures the experimentally observed sensitivity of the smallstrain shear modulus to surface roughness.

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Section: Bender Element Testingmentioning

confidence: 99%

Quantitative assessment of the influence of surface roughness on soil stiffness

et al. 2015

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“…General construction of bender element (after Dyvik & Madshus, 1985) (a); typical connection scheme signal wires (b); modifi ed connection scheme signal wires (c) a) b c w badanym ośrodku. Jeśli ten sam element piezoelektryczny zostanie podłączony za pomocą trzech przewodów (połączenie równoległe) oraz zostanie wzbudzony przez identyczny jak poprzednio impuls, to zachowa się odmiennie (Lings i Greening, 2001). Element ten zacznie drgać podłużnie, powodując powstanie w próbce gruntu fali podłuż-nej P (rys.…”

Section: Budowa I Działanie Elementów Piezoelektrycznychunclassified

“…W przypadku elementu typu extender występuje trend odwrotny, czyli stopniowe polepszanie się jakości odbieranego sygnału wraz z przyrostem TABELA 1. Zestawienie podstawowych parametrów badanych gruntów naprężeń efektywnych (Lings i Greening, 2001). Dla testowych próbek iłu otrzymane prędkości fali poprzecznej są na porównywalnym poziomie do wartości uzyskanych przez innych naukowców badających tego rodzaju grunt pobrany w tej lokalizacji (Tymiński i Markowska--Lech, 2005).…”

Section: Wyniki Badań Testowychunclassified

Wykorzystanie piezoelementów typu bender w pomiarach propagacji fali podłużnej w gruntach

Witowski

Godlewski

2017

Przegląd Naukowy Inżynieria I Kształtowanie Środowiska

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“…Bender-extender elements were accidentally discovered when the typical BE connection scheme was incorrectly performed, as detailed by Lings and Greening (2001). The most interesting feature of this transducer is its reversibility of functions: simply by altering its electrical connections, the transducer can be used to propagate P and S waves.…”

Section: Bender-extender Elements (Be)mentioning

confidence: 99%

“…The methods based on wave propagation, often called acoustic methods, can be divided into two main groups: wave transmission methods, which include the ultrasound wave transmission methods (Dumoulin et al 2012) and the bender-extender elements (Lings and Greening 2001;Zhu and Kee 2010;Silva et al 2013); and wave reflection methods (Voigt 2005;Akkaya et al 2003). These testing techniques are based on the principle that the velocity (V) of a wave in a given material varies according to its elastic properties and density.…”

Section: Introductionmentioning

confidence: 99%

Comparison Between Different Experimental Techniques for Stiffness Monitoring of Cement Pastes

Granja

Azenha

Sousa

et al. 2014

ACT

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In 2009, a new methodology for the continuous monitoring of E-modulus of cement-based materials since casting was proposed, under the designation EMM-ARM (E-modulus Measurement through Ambient Response Method). This methodology is a variant to classic resonant frequency methods that allows continuous stiffness monitoring from the instant of casting. After the encouraging results obtained in the first applications of EMM-ARM to cement pastes, the present paper gives continuity to previous developments, through validations with additional experimental methodologies and extension to thermal activation testing. At first, a comparison is performed between the results of EMM-ARM and those obtained through: pulse velocity methods (both ultrasonic contact probes and bender-extender elements), penetration resistance (Vicat needle) and cyclic compression on cylindrical specimens. Afterwards, the possibility of studying the activation energy of the stiffness evolution on tests conducted at 20ºC and 40ºC is explored.

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A novel bender/extender element for soil testing

Cited by 89 publications

References 9 publications

Quantitative assessment of the influence of surface roughness on soil stiffness

Quantitative assessment of the influence of surface roughness on soil stiffness

Wykorzystanie piezoelementów typu bender w pomiarach propagacji fali podłużnej w gruntach

Comparison Between Different Experimental Techniques for Stiffness Monitoring of Cement Pastes

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