Wave Propagation Methods for Determining Stiffness of Geomaterials

Sawangsuriya, Auckpath

doi:10.5772/48562

Cited by 14 publications

(6 citation statements)

References 104 publications

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“…Although several methods are commercially available to determine the stiffness of geomaterials, both in the laboratory and in the field, (ultrasound) wave propagation techniques are widely accepted for their rapid, non-destructive, and low-cost evaluation methods. The use of piezoelectric transducers to estimate small-strain stiffness of soils from wave velocity has been well established nowadays [16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Elastic waves in particulate glass-rubber mixtures

et al. 2021

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We investigate the propagation of waves in dense static granular packings made of soft and stiff particles subjected to hydrostatic stress. Physical experiments in a triaxial cell equipped with broadband piezoelectric wave transducers have been performed at ultrasound frequencies. The time of flight is measured in order to study the combined effect of applied stress and rubber content on the elastic properties of the mixtures. The bulk stiffness deduced from the wave speed is nonlinear and non-monotonic with the increasing percentage of rubber with a more prominent effect at higher pressures. Moreover, in the frequency domain, a spectral analysis gives insights on the transition from a glass- to a rubber-dominated regime and the influence of rubber particles on the energy dissipation. Mixtures with rubber content below 30% show enhanced damping properties, associated with slightly higher stiffness and lighter weight.

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Section: Introductionmentioning

confidence: 99%

Elastic waves in particulate glass-rubber mixtures

et al. 2021

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“…Generally, the topsoil under study has shear modulus ranging from 21,200 kPa -255,000 kPa with an average value of 93,200 kPa. Comparing these to the table of shear modulus (Table 2) generated by Sawangsuriya (2012), the geoelastic parameters of the engineering foundation fall within dense sands and gravels as well as silty sands. The Ultimate Bearing capacity depends on the soil type, moisture content, compaction and the amount of uniformity of the formation.…”

Section: Resultsmentioning

confidence: 89%

Determination of Incompressibility (Bulk Modulus), Elasticity (Young’s Modulus) and Rigidity (Shear Modulus) of Uyo and Its Environ, Southeastern Nigeria

Essien¹,

Akankpo²,

Igboekwe³

et al. 2023

GEP

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In this work, seismic refraction was used to obtain elastic properties (shear modulus (μ), Young modulus (E), Bulk modulus (K) and lithological information in Uyo and its environ as an aid to engineering foundation. Using seismic refraction method, the top and weathered layer of the engineering foundation in the study area was investigated to determine the elastic parameters of top soil and also assess the strength of engineering foundation based on the parameter distribution. A 24-channel signal enhancement seismograph, geophones, sledge hammer and a metal plate (source) for generating seismic waves were used. The study area lies between latitudes 4˚45' and 5˚15'N and between longitudes 7˚45' and 8˚30'E in the Niger Delta region of southern Nigeria. Geologically, the area is located in the Tertiary to Quaternary Coastal Plain Sands (CPS) (otherwise called the Benin Formation) and Alluvium environments of the Niger Delta region of southern Nigeria. Shear Modulus had average values of 0.43 × 10 8 N/m 2 and 1.40 × 10 8 N/m 2 for layers 1 and 2 respectively. The average values of the Young Modulus for layers 1 and 2 were determined as 2.32 × 10 8 N/m 2 and 3.84 × 10 8 N/m 2 respectively. The average values of the bulk Modulus for layers 1 and 2 were estimated as 1.52 × 10 8 N/m 2 and 4.93 × 10 8 N/m 2 respectively.

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“…The transmitting transducer transforms the input F I G U R E 2 Schematic view of wave propagation measurement setup [55] electric signal to an acoustic wave and sends it through the medium. The receiving transducer receives the propagated mechanical sound wave and transforms it back to an electronical signal which can be acquired by the digitizer, compare [27,43] for technical details on the transducers. Transducers are often incorporated in geomechanical and geophysical laboratory testing equipment such as in triaxial or oedometers cells.…”

Section: Stiffness Determination Based On Wave Propagation Measurementmentioning

confidence: 99%

Multi‐scale characterization of granular media by in situ laboratory X‐ray computed tomography

2022

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Investigations of biphasic monodisperse soft (rubber) and stiff (glass) particle mixtures under hydrostatic conditions show an interesting behavior with regard to the effective stiffness. P‐wave modulus measured by acoustic wave propagation at ultrasonic frequencies showed a significant decline while more soft particles are added, that is, higher rubber volume fractions, due to a change in the microstructure of the granular medium. However, for small volume fractions of soft particles, it could be observed that the P‐wave modulus is increasing. This result cannot be explained by classical mixture rules or effective medium theories. For the understanding of those effects, a detailed insight into the microstructure of the granular medium is necessary. To gain this information and link it later back to the measured effective mechanical properties, high‐resolution micro X‐ray computed tomography (μXRCT) imaging is a well‐established tool. With μXRCT imaging, the granular microstructure can be visualized in 3D and characterized subsequently. Combining classical effective characterization methods with μXRCT imaging can help to solve a variety of multi‐scale problems. Performing the characterization step in situ, meaning inside the laboratory‐based μXRCT scanner, has the advantage that exactly the same samples are mechanically characterized and visualized. To address the mentioned observation above, we designed a low X‐ray absorbing oedometer cell with integrated broadband piezoelectric P‐wave transducers which enables this kind of investigation inside a laboratory‐based μXRCT scanner. The focus of this contribution is on the general experimental methodology which can be transferred to other multi‐scale problems. It starts with a description of the image acquisition and ends with the post‐processing of the in situ acquired image data. To demonstrate this, cylindrical samples consisting of the same monodisperse rubber and glass particle mixtures that were studied before under hydrostatic stress conditions are considered. Selected results are presented to explain the single steps.

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Wave Propagation Methods for Determining Stiffness of Geomaterials

Cited by 14 publications

References 104 publications

Elastic waves in particulate glass-rubber mixtures

Elastic waves in particulate glass-rubber mixtures

Determination of Incompressibility (Bulk Modulus), Elasticity (Young’s Modulus) and Rigidity (Shear Modulus) of Uyo and Its Environ, Southeastern Nigeria

Multi‐scale characterization of granular media by in situ laboratory X‐ray computed tomography

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