In:
Solid Earth, Copernicus GmbH, Vol. 13, No. 2 ( 2022-02-02), p. 301-322
Abstract:
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.
Type of Medium:
Online Resource
ISSN:
1869-9529
DOI:
10.5194/se-13-301-2022
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2022
detail.hit.zdb_id:
2545676-3
