Comment on egusphere-2026-3474
Abstract
Abstract. The brittle damage around tunnels in the form of spalling is common in massive crystalline rocks subjected to high in-situ stresses. Understanding the short-term development and long-term evolution of the Excavation Damage Zone (EDZ) is particularly important for deep geological repositories (DGRs) for heat-generating nuclear waste, as the EDZ may provide preferential pathways for radionuclide migration. This paper presents an overview of the PRECODE mine-by experiment at BedrettoLab, a newly developed underground research laboratory (URL) in southern Switzerland designed to investigate brittle fracturing and EDZ evolution in crystalline rocks under repository-relevant conditions. The PRECODE tunnel was excavated in Rotondo Granite using both controlled drill-and-blast (D&B) and line-drilling and rock-breaking (LDRB) methods to evaluate the influence of excavation technique on EDZ characteristics. The experiment combines multidisciplinary in-situ monitoring including acoustic emission, distributed acoustic and strain sensing, hydraulic monitoring, electrical resistivity tomography, and terrestrial laser scanning with laboratory-based fracture mechanics and time-dependent testing under varying environmental conditions. The main objectives are to characterize short-term EDZ formation, investigate long-term crack growth and stress corrosion processes, quantify permeability evolution, and assess the interaction between excavation-induced damage and nearby fault zones. Preliminary results indicate clear differences in AE activity and EDZ development between excavation methods, while observations from the mature EDZ of the more than 40-year-old Bedretto Tunnel suggest ongoing time-dependent brittle fracturing. The coupled in-situ and laboratory datasets provide a unique basis for improving predictive models and long-term safety assessments for nuclear waste repositories in crystalline rocks.
Authors 24
-
Affiliation as printed
Chair of Engineering Geology & Hydrogeology, RWTH Aachen University, Aachen, Germany
-
Affiliation as printed
Chair of Engineering Geology & Hydrogeology, RWTH Aachen University, Aachen, Germany
-
Affiliation as printed
Chair of Engineering Geology & Hydrogeology, RWTH Aachen University, Aachen, Germany
-
ETH Zurich · Swiss Seismological Service
Affiliation as printed
Swiss Seismological Service, ETH Zurich, Zurich, Switzerland
-
ETH Zurich · Swiss Seismological Service
Affiliation as printed
Swiss Seismological Service, ETH Zurich, Zurich, Switzerland
-
Affiliation as printed
Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, Zurich, 8092, Switzerland
-
Affiliation as printed
Trent School of the Environment, Trent University, Peterborough, Ontario, Canada
-
Affiliation as printed
Department of Civil and Resource Engineering, Dalhousie University, Canada
-
ETH Zurich · Swiss Seismological Service
Affiliation as printed
Swiss Seismological Service, ETH Zurich, Zurich, Switzerland
-
Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies IEG
Affiliation as printed
Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies, IEG, Aachen, Germany
-
Affiliation as printed
Natural Resources Canada, Ontario, Canada
-
Affiliation as printed
Center for Hydrogeology and Geothermics, University of Neuchâtel, Neuchâtel, Switzerland
-
University of Science and Technology of China
Affiliation as printed
University of Science and Technology of China, School of Earth and Space Sciences, Hefei, China
-
Affiliation as printed
Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, Zurich, 8092, Switzerland
-
Affiliation as printed
Geoazur Laboratory, Valbonne, France
-
Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies IEG
Affiliation as printed
Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies, IEG, Aachen, Germany
-
Affiliation as printed
Chair of Engineering Geology & Hydrogeology, RWTH Aachen University, Aachen, Germany
-
Affiliation as printed
Department of Civil Engineering, Lassonde School of Engineering, York University, Canada
-
Affiliation as printed
Trent School of the Environment, Trent University, Peterborough, Ontario, Canada
-
Affiliation as printed
Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, Zurich, 8092, Switzerland
-
Affiliation as printed
Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, Zurich, 8092, Switzerland
-
Affiliation as printed
Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, Zurich, 8092, Switzerland
-
ETH Zurich · Swiss Seismological Service
Affiliation as printed
Swiss Seismological Service, ETH Zurich, Zurich, Switzerland
-
Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies IEG · RWTH Aachen University
Affiliation as printed
Chair of Engineering Geology & Hydrogeology, RWTH Aachen University, Aachen, Germany
Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies, IEG, Aachen, Germany
Cited by 0 stored of 0
No patents citing this paper on Lens.org (checked 2026-10-06).