Статті в журналах: "Bender element tests"

1

Viggiani, Giulia, and J. H. Atkinson. "Interpretation of bender element tests." Géotechnique 45, no. 1 (March 1995): 149–54. http://dx.doi.org/10.1680/geot.1995.45.1.149.

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2

Chaney, RC, KR Demars, R. Arulnathan, RW Boulanger, and MF Riemer. "Analysis of Bender Element Tests." Geotechnical Testing Journal 21, no. 2 (1998): 120. http://dx.doi.org/10.1520/gtj10750j.

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3

Santamarina, J. C., and M. A. Fam. "Discussion: Interpretation of bender element tests." Géotechnique 47, no. 4 (September 1997): 873–77. http://dx.doi.org/10.1680/geot.1997.47.4.873.

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4

Jovičić, V., M. R. Coop, and M. Simić. "Objective criteria for determiningGmaxfrom bender element tests." Géotechnique 46, no. 2 (June 1996): 357–62. http://dx.doi.org/10.1680/geot.1996.46.2.357.

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5

Blewett, J., I. J. Blewett, and P. K. Woodward. "Phase and amplitude responses associated with the measurement of shear-wave velocity in sand by bender elements." Canadian Geotechnical Journal 37, no. 6 (December 1, 2000): 1348–57. http://dx.doi.org/10.1139/t00-047.

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Shear-wave velocity measured by bender elements in laboratory sand samples is shown to be dependent upon the excitation frequency and exhibits a maximum velocity for a finite frequency. By comparing the relative effects of dispersion due to propagation of shear waves through sand and dispersion due to bender element performance within sand, we show that a combination of the two processes is required to explain the observations. The magnitude of the aggregate response of the bender elements and the sand implies that reliable shear-wave velocity results cannot be obtained from bender element tests without a prior knowledge of the frequency response of the entire system.Key words: shear-wave velocity, phase-sensitive detection, dispersion, attenuation, sand.

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6

Piriyakul, Keeratikan. "Experimental Study on Elastic Stiffness of Kaolinite Clay." Advanced Materials Research 813 (September 2013): 395–98. http://dx.doi.org/10.4028/www.scientific.net/amr.813.395.

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This paper presents a study on the elastic shear modulus of Kaolinite clay at very small strains under isotropic stress from triaxial tests. The Kaolinite clay sample is subjected to an isotropic stress of 100, 200 and 400 kPa. In this very small strain domain where strain is less than 10-3 %, the behaviour of clay soil shows an elastic response. In conventional triaxial test, an initial shear modulus, G0, can be measured using an external strain measurement device. Nevertheless, there is an advantage to mount local strain sensors directly on a clay sample in order to obtain more accurate measurement of G0. Also the G0 can be measured by bender elements through propagation of an elastic shear wave. Therefore in this research G0 can be obtained by external, local strain measurements and bender element tests. These results of G0 in the very small strain region are compared and show that there is a good agreement between the results from local strain measurements and bender element tests.

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7

Youn, Jun-Ung, Yun-Wook Choo, and Dong-Soo Kim. "Measurement of small-strain shear modulus Gmax of dry and saturated sands by bender element, resonant column, and torsional shear tests." Canadian Geotechnical Journal 45, no. 10 (October 2008): 1426–38. http://dx.doi.org/10.1139/t08-069.

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The bender element method is an experimental technique used to determine the small-strain shear modulus (Gmax) of a soil by measuring the velocity of shear wave propagation through a sample. Bender elements have been applied as versatile transducers to measure the Gmax of wet and dry soils in various laboratory apparatuses. However, certain aspects of the bender element method have yet to be clearly specified because of uncertainties in determining travel time. In this paper, the bender element (BE), resonant column (RC), and torsional shear (TS) tests were performed on the same specimens using the modified Stokoe-type RC and TS testing equipment. Two clean sands, Toyoura and silica sands, were tested at various densities and mean effective stresses under dry and saturated conditions. Based on the test results, methods of determining travel time in BE tests were evaluated by comparing the results of RC, TS, and BE tests. Also, methods to evaluate Gmax of saturated sands from the shear-wave velocity (Vs) obtained by RC and BE tests were investigated by comparing the three sets of test results. Biot’s theory on frequency dependence of shear-wave velocity was adopted to consider dispersion of a shear wave in saturated conditions. The results of this study suggest that the total mass density, which is commonly used to convert Gmax from the measured Vs in saturated soils, should not be used to convert Vs to Gmax when the frequency of excitation is 10% greater than the characteristic frequency (fc) of the soil.

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8

Cheng, Z., and E. C. Leong. "Determination of damping ratios for soils using bender element tests." Soil Dynamics and Earthquake Engineering 111 (August 2018): 8–13. http://dx.doi.org/10.1016/j.soildyn.2018.04.016.

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9

O’Donovan, J., C. O’Sullivan, and G. Marketos. "Two-dimensional discrete element modelling of bender element tests on an idealised granular material." Granular Matter 14, no. 6 (October 6, 2012): 733–47. http://dx.doi.org/10.1007/s10035-012-0373-9.

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10

Rahman, Muhammad E., Vikram Pakrashi, Subhadeep Banerjee, and Trevor Orr. "Suitable Waves for Bender Element Tests: Interpretations, Errors and Modelling Aspects." Periodica Polytechnica Civil Engineering 60, no. 2 (2016): 145–58. http://dx.doi.org/10.3311/ppci.7952.

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11

Fernández Lavín, Alfonso, and Efraín Ovando Shelley. "Haar Wavelet Transform for Arrival Time Identification in Bender Element Tests." Geotechnical Testing Journal 43, no. 4 (July 10, 2019): 20180400. http://dx.doi.org/10.1520/gtj20180400.

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12

Okovido, J. O., and C. Kennedy. "Effect of Confining Pressures on Dynamic Response Characteristics of Silty Soils in the Niger Delta." Nigerian Journal of Environmental Sciences and Technology 5, no. 2 (October 2021): 404–12. http://dx.doi.org/10.36263/nijest.2021.02.0258.

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The probability of earthquake occurrence in the Niger Delta region of Nigeria was studied in this research. The resonant column/bender element tests were used for the study. Series of analysis were carried out on compacted silt in subsoil strata obtained from various locations in Rivers, Bayelsa, Delta and Akwa Ibom States. The effects of confinement on frequency, shear modulus, shear velocity and damping ratio were studied. The tests results revealed that confinement has effects on the investigated parameters. Thus, frequency response increases with increase in confinement pressure. Also, the resonance column test at various confinements revealed changes in shear modulus, accelerometer output and damping ratio. Accordingly, there was high disparity in the tested parameters as confinement pressure was increased. Similarly, the bender element tests also showed that pressure has effect on shear wave-velocity, shear modulus and damping ratio confinement. The shear modulus and shear wave-velocity generally increased as confinement pressure was increased, while damping ratio decreases as confinement pressure was increased. The variations in Resonance Column/Bender Element test parameters showed that the silty soil in the Niger Delta region, an oil and gas rich area, is likely to experience earthquake in the future. Therefore, geological data should be collated for monitoring, especially as several geological activities take place in the region.

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13

Xie, Ming, Jiahao Liu, and Song Lu. "Elastic Wave Denoising in the Case of Bender Elements Type Piezoelectric Transducers." Sustainability 14, no. 19 (October 4, 2022): 12605. http://dx.doi.org/10.3390/su141912605.

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The accuracy of the wave signal is key to studying physical information inside the soil using bender-element-type piezoelectric transducers. There is too much noise during the elastic wave signal collected by bender elements, which is caused by factors such as fluid current and infiltration. At present, the mainstream method is the superposition method, which superposes multiple tested waveform data to obtain a clear waveform. However, the superposition method is limited by the number of signals during the collection, and the denoised waveform still contains high-frequency noise. A combination method combining superposition and the wavelet threshold is proposed in this work to improve the accuracy of the elastic waveform signal. Three different signal denoising simulation tests and one model box test are conducted to verify the method’s feasibility from two aspects. The results show that the combined method can effectively remove high-frequency noise and display clear waveforms based on overcoming the number of signals. This work provides a new means of signal denoising in the case of studying soil properties by bender-element-type piezoelectric transducers.

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14

Markowska-Lech, Katarzyna, Wojciech Sas, Mariusz Lech, Katarzyna Gabryś, and Alojzy Szymański. "The small strain stiffness from bender elements tests for clayey soils." Annals of Warsaw University of Life Sciences – SGGW. Land Reclamation 50, no. 4 (December 1, 2018): 353–71. http://dx.doi.org/10.2478/sggw-2018-0028.

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Abstract The shear modulus of soils at small strain (G0) is one of the input parameters in a finite element analysis with the hardening soil model with small strain stiffness, required in the advanced numerical analyses of geotechnical engineering problems. The small strain stiffness can be determined based on the seismic wave velocities measured in the laboratory and field tests, but the interpretation of test results is still under discussion because of many different factors affecting the measurements of the wave travel time. The recommendations and proposed solutions found in the literature are helpful as a guide, but ought to be adopted with a certain measure of care and caution on a case-by-case basis. The equipment, procedures, tests results and interpretation analyses of bender elements (BE) tests performed on natural overconsolidated cohesive soils are presented.

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15

Kumar, Jyant, and Ninad Sanjeev Shinde. "Interpretation of bender element test results using sliding Fourier transform method." Canadian Geotechnical Journal 56, no. 12 (December 2019): 2004–14. http://dx.doi.org/10.1139/cgj-2018-0733.

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Identification of the arrival point of the shear wave in bender element tests is a task that can have ambiguous results. The contamination of the received shear wave signal with a weak P-wave component, which can emerge either directly from the transmitter or reflect from the side boundary, makes the judgement involved in this task dubious. The different available procedures to mark the arrival times of the shear wave are often prone to errors. A method is proposed to identify the time of the arrival of the shear wave. The predominant frequency of the received signal is first evaluated and then, with the help of the sliding Fourier transform approach, the arrival of the shear wave is identified. The method does not require any manual intervention. The proposed approach is applied to bender element tests performed on dry and saturated sand and glass beads by varying (i) input frequency of the signal, (ii) confining pressure, and (iii) void ratio. Results for different cases, including those obtained by using resonant column tests, are found to be very promising.

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16

Gao, Yanbin, Xiaojun Zheng, Hao Wang, and Wenkang Luo. "Effect of Wave Attenuation on Shear Wave Velocity Determination Using Bender Element Tests." Sensors 22, no. 3 (February 7, 2022): 1263. http://dx.doi.org/10.3390/s22031263.

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Wave attenuation is a widespread physical phenomenon in most acoustic tests, but there is a scarcity of quantitative investigations into the influence of wave attenuation on the determination of shear wave travel time in bender element tests. To ascertain this attenuation effect, a series of bender element tests were conducted on clay samples with different lengths under unconfined conditions. The experimental results suggest that the real first peak of the received signal attenuates gradually with the increase of the sample length and even becomes undistinguished when the sample length exceeds a limit. This phenomenon results in misinterpretation of the wave travel time using the time domain method. In this study, the shear wave travel time is misinterpreted when wave travel distance over approximately 80 mm, leading to underestimation of the VS by 17% for the peak-to-peak approach and 10% for the arrival-to-arrival method. Therefore, besides the near field effect and boundary reflection, the wave attenuation effect turned out to be an important factor influencing the determination of VS using the time domain method. Accordingly, it is advisable to predetermine the limit test distance for a specific testing system under conditions, particularly for long distance testing.

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17

Wang, Yu-Hsing, Wai Man Yan, and Kai Fung Lo. "Damping-ratio measurements by the spectral-ratio method." Canadian Geotechnical Journal 43, no. 11 (November 1, 2006): 1180–94. http://dx.doi.org/10.1139/t06-067.

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In this paper, bender elements are used as sensors to measure the damping ratio of soil by the spectral-ratio method. The results of numerical and physical experiments suggest that adequate measurement precision can be achieved by reducing the two types of inherent biases arising from (i) the near-field effect and (ii) the different transfer functions of the two receiver bender elements. The first bias can be avoided by setting sensors to r1/λ ≥ 2.0 and r1/r2 ≥ 2.0, where r1 and r2 are the distances between the source and the first and second receivers, respectively; and λ is the wavelength. The second bias can be minimized by modifying the original spectral-ratio method to accommodate the self-healing technique. The damping ratios, measured by this modified method, obtained from the experiment conducted in a tailor-made, true-triaxial apparatus are very similar to those obtained from resonant column tests under the same state of stress.Key words: bender element, damping ratio, spectral-ratio method, near-field effect, true-triaxial apparatus.

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18

Xu, Kai, Xiaoqiang Gu, Chao Hu, and Lutong Lu. "Comparison of small-strain shear modulus and Young’s modulus of dry sand measured by resonant column and bender–extender element." Canadian Geotechnical Journal 57, no. 11 (November 2020): 1745–53. http://dx.doi.org/10.1139/cgj-2018-0823.

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The small-strain shear modulus and Young’s modulus of dry sand are simultaneously measured by resonant column and bender–extender element tests. Two different methods are adopted to calibrate the resonant column and the results indicate that the conventional calibration method may significantly underestimate the Young’s modulus obtained in flexural excitation, while it only slightly underestimates the shear modulus obtained in torsional excitation. A new calibration method that establishes a calibration curve based on the resonant frequency is used to overcome the error. With this new calibration method, the shear modulus and Young’s modulus from the resonant column agree well with those from the bender–extender element. It convincingly explains the reason why a very small Poisson’s ratio was observed in previous resonant column tests and suggests that the effect of resonant frequency on the calibration results must be considered in flexural excitation.

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19

Alaie, R., and R. Jamshidi Chenari. "Dynamic properties of EPS-sand mixtures using cyclic triaxial and bender element tests." Geosynthetics International 26, no. 6 (December 2019): 563–79. http://dx.doi.org/10.1680/jgein.19.00034.

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20

Suits, L. D., T. C. Sheahan, António Viana da Fonseca, Cristiana Ferreira, and Martin Fahey. "A Framework Interpreting Bender Element Tests, Combining Time-Domain and Frequency-Domain Methods." Geotechnical Testing Journal 32, no. 2 (2009): 100974. http://dx.doi.org/10.1520/gtj100974.

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21

Gu, Xiaoqiang, Jun Yang, Maosong Huang, and Guangyun Gao. "Bender element tests in dry and saturated sand: Signal interpretation and result comparison." Soils and Foundations 55, no. 5 (October 2015): 951–62. http://dx.doi.org/10.1016/j.sandf.2015.09.002.

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22

Chen, Guan, Fang-Tong Wang, Dian-Qing Li, and Yong Liu. "Dyadic wavelet analysis of bender element signals in determining shear wave velocity." Canadian Geotechnical Journal 57, no. 12 (December 2020): 2027–30. http://dx.doi.org/10.1139/cgj-2019-0167.

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Determining shear wave velocity is a critical technique in bender element tests, as it can be readily affected by near-field effects, wave reflection, and other factors. This study proposes a new method based on the dyadic wavelet transform modulus maxima. Combining the local modulus maxima of dyadic wavelet transform approximate coefficients at fine decomposition levels and an appropriate threshold value, the proposed method can automatically detect the target point. For validation, a comparative study among the dyadic wavelet transform modulus maxima, peak-to-peak, first arrival, and cross-correlation methods was carried out using 140 sets of bender element signals. The comparison results show that the proposed method not only mitigates the adverse effects of near-field, later major peaks, and noise contamination, but is also more robust in estimating shear wave velocity.

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23

Dyka, Ireneusz, Piotr E. Srokosz, and Marcin Bujko. "Influence of grain size distribution on dynamic shear modulus of sands." Open Engineering 7, no. 1 (November 23, 2017): 317–29. http://dx.doi.org/10.1515/eng-2017-0036.

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AbstractThe paper presents the results of laboratory tests, that verify the correlation between the grain-size characteristics of non-cohesive soils and the value of the dynamic shear modulus. The problem is a continuation of the research performed at the Institute of Soil Mechanics and Rock Mechanics in Karlsruhe, by T. Wichtmann and T. Triantafyllidis, who derived the extension of the applicability of the Hardin’s equation describing the explicite dependence between the grain size distribution of sands and the values of dynamic shear modulus. For this purpose, piezo-ceramic bender elements generating elastic waves were used to investigate the mechanical properties of the specimens with artificially generated particle distribution. The obtained results confirmed the hypothesis that grain size distribution of non-cohesive soils has a significant influence on the dynamic shear modulus, but at the same time they have shown that obtaining unambiguous results from bender element tests is a difficult task in practical applications.

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24

Okovido, J. O., and C. Kennedy. "Effect of Confining Pressures on the Dynamic Response Characteristics of Niger Delta Clay Soils." Nigerian Journal of Environmental Sciences and Technology 5, no. 2 (October 2021): 377–86. http://dx.doi.org/10.36263/nijest.2021.02.0257.

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The study investigated the earthquake potential in Niger Delta region of Nigeria. A series of resonant column and bender element test was performed on compacted clay soil samples across the investigated Niger Delta States, which showed the influence of confinement on frequency, shear modulus, shear velocity and damping ratio. The confinement in clay was high. The frequency response increases with pressure increase. Also, the resonance column test at various confinements revealed changes in shear modulus, accelerometer output and damping ratio. Thus, there was high variation in the test parameters as confinement pressure was increased. Similarly, the bender element tests also showed that pressure has effect on shear wave-velocity, shear modulus and damping ratio confinement. Although, unlike Resonance Column tests, the shear modulus and shear wave-velocity generally increased as confinement pressure was increased, while for damping ratio it decreases as confinement pressure was increased. The variations in resonance column/binder element test parameters showed that the Niger Delta region, as an oil and gas area, is susceptible to earthquake. Therefore, continuous monitoring of oil exploration activities must be put in place.

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25

Iamchaturapatr, Janjit, Keeratikan Piriyakul, and Aruz Petcherdchoo. "Use of a Piezoelectric Bender Element for the Determination of Initial and Final Setting Times of Metakaolin Geopolymer Pastes, with Applications to Laterite Soils." Sensors 22, no. 3 (February 7, 2022): 1267. http://dx.doi.org/10.3390/s22031267.

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This study proposes the use of a non-destructive testing technique, based on piezoelectric bender element tests, to determine the initial and final setting times of metakaolin geopolymer pastes. (1) Background: Metakaolin geopolymer is a new eco-friendly building material that develops strength rapidly and is high in compressive strength. (2) Methods: The initial and the final setting times were investigated via bender element and Vicat needle tests. Metakaolin powder was prepared by treating kaolin at 0, 200, 800, 1000, and 1200 °C. All metakaolin powder samples were then mixed with geopolymer solution at different mixing ratios of 0.8:1.0, 1.0:1.0, 1.2:1.0, and 1.5:1.0. The geopolymer solution was prepared by adding 10 normal concentrations of sodium hydroxide (10 N NaOH) to sodium silicate (Na2SiO3) at various solution ratios of 1.0:1.0, 1.0:1.2, 1.0:1.5, 1.0:2.0, 1.2:1.0, 1.5:1.0 and 2.0:1.0. (3) Results: The optimum temperature for treating metakaolin is established at 1000 °C, with a mixing ratio between the metakaolin powder and the geopolymer solution of 1.0:1.0, as well as a solution ratio between NaOH and Na2SiO3 of 2.0:1.0. (4) Conclusions: The use of piezoelectric bender elements to determine the initial and final setting times of metakaolin geopolymer pastes is a useful method by which to detect geopolymerization by shear wave velocity in a real-time manner. Moreover, the penetration of the Vicat apparatus can confirm the setting times at specific intervals. The relationships between the shear wave velocity and the Vicat penetration appear to be linear, with an initial setting time of 168 m/s and a final setting time of 187 m/s. Finally, the optimum metakaolin geopolymer pastes are applied to improve laterite soils, as measured by CBR tests.

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26

Moussa, Ahmed, Hany El Naggar, and Abouzar Sadrekarimi. "Dynamic characterization of tire derived aggregates using cyclic simple shear and bender element tests." Soil Dynamics and Earthquake Engineering 165 (February 2023): 107700. http://dx.doi.org/10.1016/j.soildyn.2022.107700.

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27

NISHIDA, Kohta, Hiroyuki TANAKA, Toshiyuki MITACHI, Keita MATSUDA, and Takashi OBARA. "ASSESSMENT OF SAMPLE QUALITY OF NATURAL DEPOSITED CLAYEY SOILS BY SUCTION AND BENDER ELEMENT TESTS." Doboku Gakkai Ronbunshuu C 63, no. 4 (2007): 981–92. http://dx.doi.org/10.2208/jscejc.63.981.

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28

Yoo, Jin-Kwon, and Du-Hee Park. "Evaluation of Characteristics of Shear Strength and Poisso's Ratio through Triaxial and Bender Element Tests." Journal of the Korean Geotechnical Society 30, no. 5 (May 31, 2014): 67–75. http://dx.doi.org/10.7843/kgs.2014.30.5.67.

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29

Chaney, RC, KR Demars, V. Jovičić, and MP Coop. "The Measurement of Stiffness Anisotropy in Clays with Bender Element Tests in the Triaxial Apparatus." Geotechnical Testing Journal 21, no. 1 (1998): 3. http://dx.doi.org/10.1520/gtj10419j.

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30

Styler, Mark A., and John A. Howie. "Combined Time and Frequency Domain Approach to the Interpretation of Bender-Element Tests on Sand." Geotechnical Testing Journal 36, no. 5 (July 19, 2013): 20120081. http://dx.doi.org/10.1520/gtj20120081.

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31

Kang, X., G. C. Kang, and B. Bate. "Measurement of Stiffness Anisotropy in Kaolinite Using Bender Element Tests in A Floating Wall Consolidometer." Geotechnical Testing Journal 37, no. 5 (June 3, 2014): 20120205. http://dx.doi.org/10.1520/gtj20120205.

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32

Wu, Yuxin, Jun Kang Chow, Yu-Hsing Wang, and Ghee Leng Ooi. "New Methods for Arrival Time Determination in Bender Element Tests for Time-Lapsed Vs Tomography." Journal of Geotechnical and Geoenvironmental Engineering 145, no. 9 (September 2019): 04019049. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0002102.

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33

Gabryś, Katarzyna, Emil Soból, Wojciech Sas, Raimondas Šadzevičius, and Rytis Skominas. "Warsaw Glacial Quartz Sand with Different Grain-Size Characteristics and Its Shear Wave Velocity from Various Interpretation Methods of BET." Materials 14, no. 3 (January 23, 2021): 544. http://dx.doi.org/10.3390/ma14030544.

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After obtaining the value of shear wave velocity (VS) from the bender elements test (BET), the shear modulus of soils at small strains (Gmax) can be estimated. Shear wave velocity is an important parameter in the design of geo-structures subjected to static and dynamic loading. While bender elements are increasingly used in both academic and commercial laboratory test systems, there remains a lack of agreement when interpreting the shear wave travel time from these tests. Based on the test data of 12 Warsaw glacial quartz samples of sand, primarily two different approaches were examined for determining VS. They are both related to the observation of the source and received BE signal, namely, the first time of arrival and the peak-to-peak method. These methods were performed through visual analysis of BET data by the authors, so that subjective travel time estimates were produced. Subsequently, automated analysis methods from the GDS Bender Element Analysis Tool (BEAT) were applied. Here, three techniques in the time-domain (TD) were selected, namely, the peak-to-peak, the zero-crossing, and the cross-correlation function. Additionally, a cross-power spectrum calculation of the signals was completed, viewed as a frequency-domain (FD) method. Final comparisons between subjective observational analyses and automated interpretations of BET results showed good agreement. There is compatibility especially between the two methods: the first time of arrival and the cross-correlation, which the authors considered the best interpreting techniques for their soils. Moreover, the laboratory tests were performed on compact, medium, and well-grained sand samples with different curvature coefficient and mean grain size. Investigation of the influence of the grain-size characteristics of quartz sand on shear wave velocity demonstrated that VS is larger for higher values of the uniformity coefficient, while it is rather independent of the curvature coefficient and the mean grain size.

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34

Souto, A., J. Hartikainen, and K. Özüdoˇgru. "Measurement of dynamic parameters of road pavement materials by the bender element and resonant column tests." Géotechnique 44, no. 3 (September 1994): 519–26. http://dx.doi.org/10.1680/geot.1994.44.3.519.

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35

Sun, H. M., and X. Kang. "A bender-element based dynamic penetrometer for the measurement of shear wave velocity and shear strength of in-situ soils." Géotechnique Letters 13, no. 3 (June 1, 2023): 1–22. http://dx.doi.org/10.1680/jgele.23.00023.

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The excavation of underground space during rapid urbanization requires a fully understanding of shear wave velocity (Vs-hh and Vs-hv) and shear strength parameters (cohesive strength (c) and internal friction angle (ϕ)) of soil materials. However, existing laboratory and in-situ testing techniques are usually imprecise, time-consuming and labor-intensive. In this work, a bender-element based dynamic penetrometer (BE-DP) was developed. Shear wave velocity was measured through two pairs of bender elements installed in the cone shafts. Small-strain stiffness (Ghh and Ghv) and stiffness anisotropic ratio (Ghh/Ghv) were calculated through the measured shear wave velocity. Shear strength parameters were obtained through a series of theoretical formulas. In-situ tests of fully weathered slate (FWS) and granite residual soil (GRS) were conducted by applying BE-DP. Test results indicated that FWS had obvious stiffness anisotropy while GRS had slight stiffness anisotropy, which were in consistent with SEM and TEM observations of two kinds of soils. Meanwhile, SEM and TEM observations also showed that soil particle size of FWS was much larger than that of GRS, resulting in a much larger shear wave velocity and small-strain stiffness of FWS than GRS. Due to less disturbance of in-situ tests than laboratory experiments, shear strength measured by BE-DP was a little bit larger than that measured by laboratory experiments for both FWS and GRS. In-situ test results proved that the newly developed BE-DP was feasible, robust, multifunctional and cost-effective.

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36

Choo, Jinhyun, Young-Hoon Jung, and Choong-Ki Chung. "Effect of Directional Stress History on Anisotropy of Initial Stiffness of Cohesive Soils Measured by Bender Element Tests." Soils and Foundations 51, no. 4 (August 2011): 737–47. http://dx.doi.org/10.3208/sandf.51.737.

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37

Piriyakul, Keeratikan. "Strength Development of Soft Bangkok Clay Mixed with Cement." Advanced Materials Research 813 (September 2013): 391–94. http://dx.doi.org/10.4028/www.scientific.net/amr.813.391.

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This paper presents the experimental study on the strength development of soft Bangkok clay mixed with the Portland cement type 1. The soft Bangkok clay samples were mixed with 20% by weigh of Portland cement type 1 and cured for 3, 7, 14 and 28 days. Then, these samples were performed the bender element and the unconfined compression tests. The research found the relationship between Vs, G0, Su and time with the maximum values of Vs of 378.79 m/s, G0 of 224.72 MPa and Su of 403.23 kPa respectively. Moreover, the research found that Vs and G0 were directly proportional to Su.

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38

Głuchowski, Andrzej, Zdzisław Skutnik, Marcin Biliniak, Wojciech Sas, and Diego Lo Presti. "Laboratory Characterization of a Compacted–Unsaturated Silty Sand with Special Attention to Dynamic Behavior." Applied Sciences 10, no. 7 (April 8, 2020): 2559. http://dx.doi.org/10.3390/app10072559.

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The dynamic properties of compacted non-cohesive soils are desired not only because of the risk of natural sources of dynamic excitations such as earthquakes, but mostly because of the anthropogenic impact of machines that are working on such soils. These soils are often unsaturated, which positively affects the soil’s mechanical properties. The information about the values of these parameters is highly desirable for engineers. In this article, we performed a series of tests, including oedometric tests, resonant column tests, bender element tests, and unsaturated triaxial tests, to evaluate those characteristic parameters. The results showed that sandy silt soil has a typical reaction to dynamic loading in terms of shear modulus degradation and the damping ratio curves’ characteristics, which can be modeled by using empirical equations. We found that the compaction procedure caused an over-consolidation state dependent on the moisture content during compaction effort. The article analyzed the soil properties that impact the maximum shear modulus G0 value. Those properties were suction s, confining pressure σ3, and compaction degree represented by the void ratio function f(e).

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39

Li, Q., C. W. W. Ng, and G. B. Liu. "Determination of small-strain stiffness of Shanghai clay on prismatic soil specimen." Canadian Geotechnical Journal 49, no. 8 (August 2012): 986–93. http://dx.doi.org/10.1139/t2012-050.

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Although a large number of tunnels and deep excavations have been constructed in Shanghai, small-strain stiffness properties of natural Shanghai clay have rarely been reported in the literature. In this study, the degree of inherent stiffness anisotropy of natural Shanghai clay was investigated in a triaxial apparatus equipped with local strain transducers and a shear-wave velocity measurement system. Three sets of side-mounted bender elements, consisting of one transmitter and two receivers each, were installed on a prismatic specimen. Two series of triaxial tests on prismatic specimens of intact Shanghai clay were carried out under an isotropic stress state. Shear-wave velocities and hence elastic shear moduli in different planes were determined from bender element measurements. The cross-correlation method using two received signals gives rise to the most objective and repeatable results on shear-wave velocities in comparison with other commonly used methods. Intact Shanghai clay clearly exhibits inherent stiffness anisotropy in terms of its elastic shear modulus ratio (G0(hh)/G0(hv)) of about 1.2 for a mean effective stress varying from 50 to 400 kPa. The measured higher stiffness in the horizontal plane may be attributed to the stronger layering structure in the horizontal bedding plane. A unique relationship is found that relates the normalized shear moduli to the stress state in each plane by incorporating a void ratio function in the form of F(e) = e–2.6.

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40

Papadopoulou, Anthi I., and Theodora M. Tika. "Laboratory-Based Correlation between Liquefaction Resistance and Shear Wave Velocity of Sand with Fines." Geotechnics 1, no. 2 (September 26, 2021): 219–42. http://dx.doi.org/10.3390/geotechnics1020012.

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This paper presents the results of a laboratory investigation into the effect of non-plastic fines on the correlation between liquefaction resistance and the shear wave velocity of sand. For this purpose, undrained stress-controlled cyclic triaxial and bender element tests were performed on clean sand and its mixtures with non-plastic silt. It is shown that the correlation between liquefaction resistance and shear wave velocity depends on fines content and confining effective stress. Based on the test results, correlation curves between field liquefaction resistance and overburden stress corrected shear wave velocity for sand containing various contents of fines are derived. These curves are compared to other previously proposed by field and laboratory studies.

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Kawaguchi, Takayuki, Toshihiro Ogino, Satoshi Yamashita, and Shunzo Kawajiri. "Identification method for travel time based on the time domain technique in bender element tests on sandy and clayey soils." Soils and Foundations 56, no. 5 (October 2016): 937–46. http://dx.doi.org/10.1016/j.sandf.2016.08.017.

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42

He, Huan, Meghdad Payan, and Kostas Senetakis. "The behaviour of a recycled road base aggregate and quartz sand with bender/extender element tests under variable stress states." European Journal of Environmental and Civil Engineering 25, no. 1 (November 24, 2018): 152–69. http://dx.doi.org/10.1080/19648189.2018.1521749.

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43

Xia, Changqing, Fanli Meng, Min Zhu, Yan Tang, and Chengyuan Lu. "Influence of Lateral Multistage Unloading Intensity on Mechanical Properties of Reconstituted Coastal Soils Containing Silty Particles." Applied Sciences 12, no. 7 (April 5, 2022): 3651. http://dx.doi.org/10.3390/app12073651.

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The unclear understanding of the mechanical behavior of soil under unloading conditions is a significant reason for the frequent occurrence of accidents and difficulties in the deformation control of foundation pit engineering in coastal areas. This paper discusses the effect of multistage unloading intensity on the mechanical properties of reconstituted coastal soils containing silty particles through a series of laboratory tests, namely, the CU triaxial, bender-element, and permeability tests. Results indicate that, with an increase in unloading intensity, the shear strength and stiffness parameters decrease, while permeability slightly increases. The effect of unloading intensity on the mechanical properties of silt and mucky silty clay is more pronounced. Additional consideration should be given to the effect of a single excavation depth on the mechanical properties of fine-grained soil in foundation pit engineering in order to ensure the stability of the surrounding soil and the safety of adjacent structures.

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44

Bian, Jiang, Hao Wu, Xing Xiao, Qi Wu, and Zheng-Long Zhou. "Experimental Study on the Gmax Characteristics of the Sand-Silt Mixed Soil Materials Using Bender Element Testing." Materials 15, no. 18 (September 6, 2022): 6200. http://dx.doi.org/10.3390/ma15186200.

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To study the small strain shear modulus (Gmax) of saturated sand-silt mixed soil materials, a series of tests were conducted using the bender element apparatus, and the influences of fines content (FC), relative density (Dr), and effective confining pressure (σ′3c) were taken into consideration. The test results indicate that the Gmax of the mixed soil materials decreases first and then increases with the FC up to 100% with Dr = 35% and 50%, while the Gmax decreases with the increasing FC when Dr = 60%. Moreover, for a given Dr, the Gmax increases with the increasing σ′3c, and the increase rate keeps constant under various FCs. The Gmax of specimens under various FCs decreases with the increase of the void ratio (e). The decrease rate between the Gmax and e differs when the σ′3c is given, which is influenced by the FC. The Gmax of the mixed soil materials can be evaluated by the Hardin model when the FC is determined. The best-fitting parameter A of the Hardin model first decreases and then increases as FC increases. The revised Hardin model, considering the influence of FC, σ′3c, and e, can be used to evaluate the Gmax for different types of sand-silt mixed soil materials. The error between the evaluated and tested Gmax is less than 10%.

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45

Marks, S., T. J. Larkin, and M. J. Pender. "The dynamic properties of a pumiceous sand." Bulletin of the New Zealand Society for Earthquake Engineering 31, no. 2 (June 30, 1998): 86–102. http://dx.doi.org/10.5459/bnzsee.31.2.86-102.

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The seismic site response analysis of sand deposits requires an understanding of the dynamic properties of the soils involved. Most dynamic soil data available in the literature has been derived for sands which do not contain pumice. Consequently, the relevance of this data to the behaviour of pumice sands is unclear. An extensive experimental investigation of the dynamic response of a pumice sand was therefore undertaken. The liquefaction response obtained from cyclic triaxial tests, and the shear modulus variation with strain amplitude observed in bender element and dynamic torsion tests were examined. The cyclic triaxial test results indicated that the liquefaction response was similar to that observed for quartz sands. However, the low strain shear modulus of the pumice sand was found to be significantly less than that of quartz sands at similar relative densities, and the nonlinear stress-strain behaviour was markedly different from that of other sands, particularly in the mid strain range.

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46

Kang, Mingu, Joon Han Kim, Issam I. A. Qamhia, Erol Tutumluer, and Mark H. Wayne. "Geogrid Stabilization of Unbound Aggregates Evaluated Through Bender Element Shear Wave Measurement in Repeated Load Triaxial Testing." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 3 (February 27, 2020): 113–25. http://dx.doi.org/10.1177/0361198120908230.

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This paper describes the use of the bender element (BE) shear wave measurement technology for quantifying the effectiveness of geogrid stabilization of unbound aggregate materials with improved mechanical properties from repeated load triaxial testing. Crushed stone aggregate specimens were prepared with three different gradations, that is, upper bound (UB), mid-range engineered (ENG), and lower bound, according to the dense graded base course gradation specification in Illinois. The specimens were compacted at modified Proctor maximum dry densities and optimum moisture contents. Two geogrids with different triaxial aperture sizes were placed at specimen mid-height, and unstabilized specimens with no geogrid were also prepared for comparison. To measure shear wave velocity, three BE pairs were placed at different heights above geogrid. Repeated load triaxial tests were conducted following the AASHTO T307 standard resilient modulus test procedure, while shear wave velocity was measured from the installed BE pairs. After initial specimen conditioning, and at low, intermediate, and high applied stress states, both the resilient moduli and accumulated permanent strains were determined to relate to the geogrid local stiffening effects in the specimens quantified by the measured shear wave velocities. The resilient modulus and shear wave velocity trends exhibited a directly proportional relationship, whereas permanent strain and shear wave velocity values were inversely related. The enhancement ratios calculated for the geogrid stabilized over the unstabilized specimens showed significant improvements in mechanical behavior for the UB and ENG gradations, and a maximum enhancement was achieved for the engineered gradation specimens stabilized with the smaller aperture geogrid.

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47

Petcherdchoo, Aruz, Sakol Pochalard, and Keeratikan Piriyakul. "Use of bender element tests for determining shear modulus of fly-ash and cement admixed Bangkok clay with considering unconfined compressive strength." Case Studies in Construction Materials 18 (July 2023): e02040. http://dx.doi.org/10.1016/j.cscm.2023.e02040.

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48

Toyota, Hirofumi, and Susumu Takada. "Effects of gravel content on liquefaction resistance and its assessment considering deformation characteristics in gravel – mixed sand." Canadian Geotechnical Journal 56, no. 12 (December 2019): 1743–55. http://dx.doi.org/10.1139/cgj-2018-0575.

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Many reports describe overestimation of liquefaction resistance based on sounding data related to ground materials containing coarse particles such as gravel and cobbles. Better methods of liquefaction potential estimation must be developed using investigation data other than those from sounding. Gathering perfect and undisturbed samples is difficult, but using seismic methods such as PS logging might be effective for assessing liquefaction potential. For this study, bender element (BE) tests and local small strain (LSS) tests were conducted, respectively, to measure the dynamic and static shear moduli of gravel – mixed sand specimens. Subsequently, relations between liquefaction strength and secant shear moduli were examined to provide reliable estimation of liquefaction in gravel – mixed sand. Although the liquefaction resistance increased considerably with overconsolidation, the initial shear modulus exhibited only a slight change with the same overconsolidation. The experimentally obtained results elucidated that the important shear strain level, for which secant shear modulus has a strong relation with liquefaction strength, was not a linear elastic region of 0.001%: it was about 0.01%.

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49

Zhou, Yifeng, Xing Xiao, Zhenglong Zhou, and Qi Wu. "Experimental Study on Maximum Dynamic Shear Modulus of Yangtze River Overconsolidated Floodplain Soft Soils." Applied Sciences 13, no. 8 (April 9, 2023): 4733. http://dx.doi.org/10.3390/app13084733.

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This study conducted experimental tests on the undisturbed Nanjing Yangtze River floodplain soft soil using the bender element instrument to determine the maximum dynamic shear modulus of the Yangtze River floodplain overconsolidated soft soil. The Gmax of floodplain soft soil with different overconsolidated ratio OCR, initial effective confining pressure σ3c′, and void ratio e are discussed. The results indicated that Gmax reduced as e rose for given σ3c′ and OCR. In addition, an increase in OCR contributed to a gradual decrease in the decay rate of Gmax, while the Gmax decay rate is insensitive to the change of σ3c′. The void ratio-normalized maximum shear modulus Gmax/F(e) improved with the increase in the stress-normalized initial effective confining pressure σ3c′/Pa, whereas the growth rate gradually drops, and a power relationship is then obtained between Gmax/F(e) and σ3c′/Pa. Based on the regression analysis, a Gmax prediction method is established for reasonably characterizing Yangtze River floodplain soft soils with various over-consolidation states, initial stress conditions, and compactness levels, with a prediction error of less than 10%.

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Fang, Yi, Yuejun Lv, XingYuan Zhou, and Yanju Peng. "Experimental Study of the Engineering Mechanical Properties of the Foundation Soil for Offshore Wind Power Platforms." Shock and Vibration 2021 (October 14, 2021): 1–12. http://dx.doi.org/10.1155/2021/1382740.

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Most of the coastal beach zone in the world is rich in wind energy reserves and has great potential for offshore wind power development. However, the sedimentary environment in the coastal area is complex and changeable, and the nature of the foundation soil of offshore wind power platforms is weak and complex, which is quite different from that in the land areas. In order to systematically study the mechanical properties of marine foundation soils, a series of geotechnical tests are carried out on representative undisturbed seabed soils, such as basic laboratory geotechnical tests, bender element tests, undrained triaxial shear tests, and resonance column tests. The test results show that shear wave velocity (Vs) of marine silt and silty clay increases linearly with the buried depth; the stress-strain relationship curves of silty clay and silt present two different modes of development: strain hardening and strain softening, the undrained shear strength (Sd) of the two types of marine soils decreases with the increase of the void ratio (e), and both present a good single correlation. Based on the relationship between Sd and Vs from the laboratory test of disturbed seabed soils, an undrained strength evaluation method of undisturbed seabed soils under the current stratum conditions incorporating in situ shear wave velocity is established. The dynamic shear modulus (G) in the various strain ranges of undisturbed silty clay and silt increases regularly with the buried depth (H). Meanwhile, the maximum dynamic shear modulus (Gmax) linearly increases with the increase of H, whereas the attenuation relationship of G decreases with the increase of H. The prediction method of G based on buried depth is established with high accuracy.

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