Investigations of Fracture Zones in Crystalline Rock by Borehole Radar

Olsson, Olle; Falk, L.; Forslund, O.; Lundmark, Lars; Sandberg, E.

doi:10.1557/proc-50-145

Cited by 7 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9) exhibits is a known ambiguity of borehole GPR surveys. This artifact is introduced by projecting the fault or fracture plane that intersects the borehole in 3D onto 2D space (Olsson et al, 1985). To overcome this issue, Hediger (2020) performed the correlation between the structures inferred from GPR reflections and ATV/OTV data, in an effort to delineate the major fault zones and fractures.…”

Section: Geophysical Imagingmentioning

confidence: 99%

Multi-disciplinary characterizations of the BedrettoLab – a new underground geoscience research facility

Hertrich

Amann

et al. 2022

Solid Earth

View full text Add to dashboard Cite

Abstract. The increased interest in subsurface development (e.g., unconventional hydrocarbon, engineered geothermal systems (EGSs), waste disposal) and the associated (triggered or induced) seismicity calls for a better understanding of the hydro-seismo-mechanical coupling in fractured rock masses. Being able to bridge the knowledge gap between laboratory and reservoir scales, controllable meso-scale in situ experiments are deemed indispensable. In an effort to access and instrument rock masses of hectometer size, the Bedretto Underground Laboratory for Geosciences and Geoenergies (“BedrettoLab”) was established in 2018 in the existing Bedretto Tunnel (Ticino, Switzerland), with an average overburden of 1000 m. In this paper, we introduce the BedrettoLab, its general setting and current status. Combined geological, geomechanical and geophysical methods were employed in a hectometer-scale rock mass explored by several boreholes to characterize the in situ conditions and internal structures of the rock volume. The rock volume features three distinct units, with the middle fault zone sandwiched by two relatively intact units. The middle fault zone unit appears to be a representative feature of the site, as similar structures repeat every several hundreds of meters along the tunnel. The lithological variations across the characterization boreholes manifest the complexity and heterogeneity of the rock volume and are accompanied by compartmentalized hydrostructures and significant stress rotations. With this complexity, the characterized rock volume is considered characteristic of the heterogeneity that is typically encountered in subsurface exploration and development. The BedrettoLab can adequately serve as a test-bed that allows for in-depth study of the hydro-seismo-mechanical response of fractured crystalline rock masses.

show abstract

Section: Geophysical Imagingmentioning

confidence: 99%

Multi-disciplinary characterizations of the BedrettoLab – a new underground geoscience research facility

Hertrich

Amann

et al. 2022

Solid Earth

View full text Add to dashboard Cite

show abstract

“…The chevron type (V-shaped) pattern that the reflector (Figure 9) exhibits is a known ambiguity of borehole GPR surveys. This artifact is introduced by projecting the fault/fracture plane that intersects the borehole in 3D onto 2D space (Olsson et al, 1985). To overcome this issue, Hediger (2020) performed the correlation between the structures inferred from GPR reflections and ATV/OTV data, in an effort to delineate the major fault zones and fractures.…”

Section: Geophysical Imagingmentioning

confidence: 99%

Multi-disciplinary characterizations of the Bedretto Lab – a unique underground geoscience research facility

Hertrich

Amann

et al. 2021

Preprint

View full text Add to dashboard Cite

Abstract. The increased interest in subsurface development (e.g., unconventional hydrocarbon, deep geothermal, waste disposal) and the associated (triggered or induced) seismicity calls for a better understanding of the hydro-seismo-mechanical coupling in fractured rock masses. Being able to bridge the knowledge gap between laboratory and reservoir scales, controllable meso-scale in situ experiments are deemed indispensable. In an effort to access and instrument rock masses of hectometer size, the Bedretto Underground Laboratory for Geosciences and Geoenergies (‘Bedretto Lab’) was established in 2018 in the existing Bedretto Tunnel (Ticino, Switzerland), with an average overburden of 1000 m. In this paper, we introduce the Bedretto Lab, its general setting and current status. Combined geological, geomechanical and geophysical methods were employed in a hectometer-scale rock mass explored by several boreholes to characterize the in situ conditions and internal structures of the rock volume. The rock volume features three distinct units, with the middle fault zone sandwiched by two relatively intact units. The middle fault zone unit appears to be a representative feature of the site, as similar structures repeat every several hundreds of meters along the tunnel. The lithological variations across the characterization boreholes manifest the complexity and heterogeneity of the rock volume, and are accompanied by compartmentalized hydrostructures and significant stress rotations. With this complexity, the characterized rock volume is considered characteristic of the heterogeneity that is typically encountered in subsurface exploration and development. The Bedretto Lab can adequately serve as a test-bed that allows for in-depth study of the hydro-seismo-mechanical response of fractured crystalline rock masses.

show abstract

“…Deployment of GPR in this form commenced in the late 1970's with development of borehole deployed antennas. The biggest driver for borehole GPR was the ability to assess fractured rock mass for suitability for nuclear waste disposal [151,152]. A more extensive push for hydrogeological applications occurred in the 1990s for smaller scale applications [153].…”

Section: Tomographic Multi-offset Radar and Borehole Radarmentioning

confidence: 99%

A review of Ground Penetrating Radar application in civil engineering: A 30-year journey from Locating and Testing to Imaging and Diagnosis

Lai

Dérobert

Annan³

2018

NDT & E International

381

View full text Add to dashboard Cite

Investigations of Fracture Zones in Crystalline Rock by Borehole Radar

Cited by 7 publications

References 0 publications

Multi-disciplinary characterizations of the BedrettoLab – a new underground geoscience research facility

Multi-disciplinary characterizations of the BedrettoLab – a new underground geoscience research facility

Multi-disciplinary characterizations of the Bedretto Lab – a unique underground geoscience research facility

A review of Ground Penetrating Radar application in civil engineering: A 30-year journey from Locating and Testing to Imaging and Diagnosis

Contact Info

Product

Resources

About