Ultrasonic, Sonic ans Seismic Waves Velocity in Shale from Tournemire Tunnel. Impact of Anisotropy and Natural Fractures

Zinszner, B.; Meynier, P.; Cabrera, Justo; Volant, P.

doi:10.2516/ogst:2002022

Cited by 13 publications

(5 citation statements)

References 2 publications

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“…In common with previous studies (Zinszner et al, 2002;Gettemy et al, 2004;Rempe et al, 2013), the laboratory and outcrop studies both indicate the overwhelming influence of fracturing on shear wave velocities in greywacke. We have also described the variability in the fault zone rock material, rock mass characteristics, and shear wave velocity structure of the SFD.…”

Section: Discussionmentioning

confidence: 51%

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Defining fault avoidance zones and associated geotechnical properties using MASW: a case study on the Springfield Fault, New Zealand

Duffy

Campbell

Finnemore

et al. 2014

Engineering Geology

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a b s t r a c tThe Springfield thrust fault at Dalethorpe, west Canterbury, New Zealand, provides a test case to explore the correlation between shear wave velocities at a range of scales, and direct field observations of distributed deformation and outcrop properties. The Springfield fault ruptures to the surface through hard Torlesse greywacke, overlain on a flight of late Quaternary glacio-fluvial terraces by~5 m of gravel. Fault slip has displaced all but the lowest terraces, revealing the geometry and location of faulting. We used multi-channel analysis of surface waves and meter-scale cross-hole measurements to map shear wave velocities below the lowest, apparently undisplaced, terrace. We correlated these surveys with geotechnical parameters measured at outcrops and investigated relationships in the laboratory. Both field and laboratory results indicate that the shear wave velocity of Torlesse greywacke declines sharply with increasing fracture density. Field surveys further indicate that relatively unweathered, high velocity greywacke is being exhumed in a bivergent wedge between two oppositefacing thrusts. The fracturing and low shear wave velocities are focused in a wide, low-velocity damage zone that has developed in the hanging wall of the main thrust, and a smaller but similar feature in the hanging wall of the backthrust. This is consistent with the geomorphology of the site. Our correlations of geomorphic indicators of deformation with fault zone velocity structure provide a useful method with which to characterize the distribution of cumulative strain. This type of analysis has utility for land use planning on, or close to, active faults, especially where they are obscured by fluvial deposits.

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Section: Discussionmentioning

confidence: 51%

“…Zinszner et al, 2002;Gettemy et al, 2004;Rempe et al, 2013), which control the dispersion and velocity of Rayleigh waves . The dispersion and velocity of Rayleigh waves are used in surface wave surveys to determine changes in shear wave velocities with depth (Stokoe et al, 1994;Park et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Defining fault avoidance zones and associated geotechnical properties using MASW: a case study on the Springfield Fault, New Zealand

Duffy

Campbell

Finnemore

et al. 2014

Engineering Geology

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“…[15], while we use the sound speed of shale calibrated in ref. [70]. The parameters for (22) is hence adopted as follows:

\gamma _0 = 1.0

\alpha = 2.33

U_0 = 3100

m/s,

s_1 = 1.41

s_2 = s_3 = 0

.…”

Section: Resultsmentioning

confidence: 99%

A MPM Lagrangian‐Eulerian hydrocode for simulating buried explosions in transversely isotropic geomaterials

Xiao,

Sun

2024

Num Anal Meth Geomechanics

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Shock waves in geological materials are characterized by a sudden release of rapidly expanding gas, liquid, and solid particles. These shock waves may occur due to explosive volcanic eruptions or be artificially triggered. In fact, underground explosions have often been used as an engineering solution for large‐scale excavation, stimulating oil and gas recovery, creating cavities for underground waste storage, and even extinguishing gas field fires. As such, hydrocodes capable of simulating the rapid and significant deformation under extreme conditions can be a valuable tool for ensuring the safety of the explosions. Nevertheless, as most of the hydrocodes are often formulated in an Eulerian grid, this setting makes it non‐trivial to track the deformation configuration of the materials without a level set. The objective of this paper is to propose the use of the material point method equipped with appropriate equation of state (EOS) models as a hydrocode suitable to simulate underground explosions of transverse isotropic geomaterials. To capture the anisotropic effect of the common layered soil deposits, we introduce a new MPM hydrocode where an anisotropic version of the Mie‐Gruneisen EOS is coupled with a frictional Drucker‐Prager plasticity model to replicate the high‐strain‐rate constitutive responses of soil. By leveraging the Lagrangian nature of material points to capture the historical dependence and the Eulerian calculation of internal force, the resultant model is capable of simulating the rapid evolution of geometry of the soil as well as the high‐strain‐rate soil mechanics of anisotropic materials.

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“…Geophysical methods can be used to assess the anisotropy associated with the texture of shales. Various studies have been dedicated to the anisotropy of the seismic velocities of rocks (see for instance Zinszner et al, 2002;Yenugu, 2010;Singh and Sircar, 2014). The impact of the fabric tensor on the electrical conductivity tensor has been investigated by Niu et al (2017).…”

Section: Introductionmentioning

confidence: 99%

Induced polarization of clay-rich materials — Part 2: The effect of anisotropy

et al. 2023

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We investigate the anisotropy in the complex conductivity of a clayrock formation through both laboratory and in situ measurements. Laboratory measurements have been conducted on four samples from two cores of the Callovo-Oxfordian formation from the Paris Basin (France). This clay-rock formation is anisotropic with a well-defined bedding plane. Two of the cylindrical core samples are taken in the transverse direction with respect to the bedding plane while two other core samples are taken in the in-plane direction. The complex conductivity spectra are performed in the frequency range 20 mHz to 45 kHz and in a broad pore water saturation range from near saturation to a residual saturation of ~25%. The complex conductivity spectra are fitted with a double Cole Cole model, the low-frequency contribution corresponding to induced polarization effect while the high-frequency contribution is related to the Maxwell-Wagner polarization. The six Cole Cole parameters are investigated as a function of saturation and we evaluate their degree of anisotropy versus the effect of saturation. The low-frequency instantaneous conductivity and normalized chargeability show a consistent degree of anisotropy with an anisotropy ratio equal to 3.8 ± 0.5 for one core sample and 6.5 ± 0.9 for the second core sample. These values represent a substantial level of anisotropy. The low-frequency Cole Cole exponent and relaxation time do not show substantial amount of anisotropy. The monitoring of the evolution of the weight in the controlled humidity chamber seems to indicate that their relative permeabilities do not show a strong anisotropic behavior. Finally, the laboratory data are discussed in the context of field data obtained with an azimuthal array of 12 electrodes.

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Ultrasonic, Sonic ans Seismic Waves Velocity in Shale from Tournemire Tunnel. Impact of Anisotropy and Natural Fractures

Cited by 13 publications

References 2 publications

Defining fault avoidance zones and associated geotechnical properties using MASW: a case study on the Springfield Fault, New Zealand

Defining fault avoidance zones and associated geotechnical properties using MASW: a case study on the Springfield Fault, New Zealand

A MPM Lagrangian‐Eulerian hydrocode for simulating buried explosions in transversely isotropic geomaterials

Induced polarization of clay-rich materials — Part 2: The effect of anisotropy

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