Damage Assessment of Supporting Pillars in an Underground Cave Using Joint Inversion of Electrical Resistivity and P-wave Velocity, Burgundy (France)

2021 ◽  
Author(s):  
A. Carrier ◽  
P. Bottelin ◽  
L. Fabre ◽  
A. Mathy
Keyword(s):  
Electrical Resistivity ◽  
Wave Velocity ◽  
Damage Assessment ◽  
Joint Inversion ◽  
P Wave ◽  
P Wave Velocity

Multiscale fracture density analysis at Stromboli Volcano, Italy: implications to flank stability

2021 ◽  
Author(s):  
Thomas Alcock ◽  
Sergio Vinciguerra ◽  
Phillip Benson ◽  
Federico Vagnon
Keyword(s):  
Electrical Resistivity ◽  
Wave Velocity ◽  
Rift Zone ◽  
Pulse Generator ◽  
Average Length ◽  
Crack Density ◽  
P Wave ◽  
Fracture Density ◽  
Stromboli Volcano ◽  
P Wave Velocity

<p>Stromboli volcano has experienced four sector collapses over the past 13 thousand years, resulting in the formation of the Sciara del Fuoco (SDF) horseshoe-shaped depression and an inferred NE / SW striking rift zone across the SDF and the western sector of the island. These events have resulted in the formation of steep depressions on the slopes on the volcano where episodes of instability are continuously being observed and recorded. This study aims to quantify the fracture density inside and outside the rift zone to identify potential damaged zones that could reduce the edifice strength and promote fracturing. In order to do so we have carried out a multiscale analysis, by integrating satellite observations, field work and seismic and electrical resistivity analyses on cm scales blocks belonging to 11 lava units from the main volcanic cycles that have built the volcano edifice, ie. Paleostromboli, Nestromboli and Vancori. 0.5 m resolution Pleiades satellite data has been first used to highlight 23635 distinct linear features across the island. Fracture density has been calculated using Fracpaq based on the Mauldon et al (2001) method to determine the average fracture density of a given area on the basis of the average length of drawn segments within a predetermined circular area. 41.8 % of total fracture density is found around intrusions and fissures, with the summit area and the slopes of SDF having the highest average fracture density of 5.279  . Density, porosity, P- wave velocity in dry and wet conditions and electrical resistivity (in wet conditions) were measured  via an ultrasonic pulse generator and acquisition system (Pundit) and an on purpose built measuring quadrupole on cm scale blocks of lavas collected from both within and outside the proposed rift zone to assess the physical state and the crack damage of the different lava units.  Preliminary results show that P-wave velocity between ~ 2.25 km/s < Vp < 5km/s decreases with porosity while there is high variability electrical resistivity with 21.7 < ρ < 590 Ohm * m. This is presumably due to the lavas texture and the variable content of bubble/vesicles porosity and crack damage, that is reflected by an effective overall porosity between 0 and 9 %. Higher porosity is generally mirrored by lower p-wave velocity values. Neostromboli blocks show the most variability in both P-wave velocity and electrical resistivity. Further work will assess crack density throughout optical analyses and systematically investigate the UCS and elastic moduli. This integrated approach is expected to provide a multiscale fracture density and allow to develop further laboratory testing on how slip surfaces can evolve to a flank collapse at Stromboli.</p>

Assessment of engineering behaviour of an intensely weathered swelling mudstone under full range of seasonal variation and the relationships among measured parameters

2018 ◽  
Vol 55 (12) ◽  
pp. 1837-1849 ◽  
Author(s):  
Zhixiong Zeng ◽  
Lingwei Kong ◽  
Min Wang ◽  
Hossain Md. Sayem
Keyword(s):  
Electrical Resistivity ◽  
Shear Strength ◽  
Wave Velocity ◽  
Full Range ◽  
Aggregate Size ◽  
Physical And Mechanical Properties ◽  
Inverse Correlation ◽  
Strong Relationship ◽  
P Wave ◽  
P Wave Velocity

An experimental study was conducted to investigate the physical and mechanical properties of an intensely weathered mudstone from Northeast China after wetting–drying (W–D), freezing–thawing (F–T), and wetting–drying–freezing–thawing (W–D–F–T) cycles. These cyclic climatic processes have significant effects on the volume, microstructure, stress–strain behaviour, shear strength, electrical resistivity, and P-wave velocity of the samples. The variation in electrical resistivity exhibits an inverse correlation with the volume change, and a strong relationship can be observed between the electrical resistivity and porosity. The cohesion decreases with increasing number of cycles, while the internal friction angle slightly increases; these relationships can be caused by the presence of cracks and large voids and by the increase in the aggregate size and density during the drying and freezing processes, respectively. Moreover, the W–D–F–T cycles have a greater influence on the shear strength than do either the W–D or F–T cycles. This phenomenon is similar to that observed in the P-wave velocity, and the relationships between the shear strength parameters and P-wave velocity are also explored. This study provides nondestructive methods of predicting the deformation and shear strength of mudstones in seasonally frozen regions.

Measurement of P-wave velocity and electrical resistivity in the tunnel seepage sections

2019 ◽  
Author(s):  
Kenji Okazaki ◽  
Shusaku Yamazaki ◽  
Toshiyuki Kurahashi ◽  
Tomio Inazaki ◽  
Hiroumi Niwa ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Wave Velocity ◽  
P Wave ◽  
P Wave Velocity

Poststack, prestack, and joint inversion of P- and S-wave data for Morrow A sandstone characterization

2015 ◽  
Vol 3 (3) ◽  
pp. SZ59-SZ92 ◽  
Author(s):  
Paritosh Singh ◽  
Thomas L. Davis ◽  
Bryan DeVault
Keyword(s):  
Wave Velocity ◽  
Seismic Data ◽  
Joint Inversion ◽  
Wave Impedance ◽  
P Wave ◽  
S Wave ◽  
Wave Data ◽  
Wave Inversion ◽  
Density Maps ◽  
P Wave Velocity

Exploration for oil-bearing Morrow sandstones using conventional seismic data/methods has a startlingly low success rate of only 3%. The S-wave velocity contrast between the Morrow shale and A sandstone is strong compared with the P-wave velocity contrast, and, therefore, multicomponent seismic data could help to characterize these reservoirs. The SV and SH data used in this study are generated using S-wave data from horizontal source and horizontal receiver recording. Prestack P- and S-wave inversions, and joint P- and S-wave inversions, provide estimates of P- and S-wave impedances, and density for characterization of the Morrow A sandstone. Due to the weak P-wave amplitude-versus-angle response at the Morrow A sandstone top, the density and S-wave impedance estimated from joint P- and S-wave inversions were inferior to the prestack S-wave inversion. The inversion results were compared with the Morrow A sandstone thickness and density maps obtained from well logs to select the final impedance and density volume for interpretation. The P-wave impedance estimated from prestack P-wave data, as well as density and S-wave impedance estimated from prestack SV‐wave data were used to identify the distribution, thickness, quality, and porosity of the Morrow A sandstone. The stratal slicing method was used to get the P- and S-wave impedances and density maps. The S-wave impedance characterizes the Morrow A sandstone distribution better than the P-wave impedance throughout the study area. Density estimation from prestack inversion of SV data was able to distinguish between low- and high-quality reservoirs. The porosity volume was estimated from the density obtained from prestack SV-wave inversion. We found some possible well locations based on the interpretation.

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