Understanding spatial and temporal evolution of progressive excavation damage zone in granitic rocks – development of a novel mine-by and laboratory experimental framework at the BedrettoLab
- 1RWTH Aachen University (Aachen, Germany)
Abstract
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.
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BibTeX
@article{hamdi2026understanding,
title = {{Understanding spatial and temporal evolution of progressive excavation damage zone in granitic rocks – development of a novel mine-by and laboratory experimental framework at the BedrettoLab}},
author = {Pooya Hamdi and Jonas Dickmann and Michal Kruszewski and Antonio Pio Rinaldi and Linus Villiger and Alexis Shakas and Mathew Perras and Navid Bahrani and Patrick Bianchi and Peter Achtziger-Zupančič and Steven Gaines and Kai Bröker and Xiaodong Ma and Paul A. Selvadurai and Virginie Durand and Kavan Khaledi and Mohammadreza Jalali and Yousef Golabchi and Sam Harris and Alba Zappone and Mathilde Wimez and Marian Hertrich and Stefan Wiemer and Florian Amann},
journal = {Solid Earth},
year = {2026},
month = oct,
doi = {10.5194/se-17-1139-2026},
url = {https://se.copernicus.org/articles/17/1139/2026/},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Understanding spatial and temporal evolution of progressive excavation damage zone in granitic rocks – development of a novel mine-by and laboratory experimental framework at the BedrettoLab
AU - Pooya Hamdi
AU - Jonas Dickmann
AU - Michal Kruszewski
AU - Antonio Pio Rinaldi
AU - Linus Villiger
AU - Alexis Shakas
AU - Mathew Perras
AU - Navid Bahrani
AU - Patrick Bianchi
AU - Peter Achtziger-Zupančič
AU - Steven Gaines
AU - Kai Bröker
AU - Xiaodong Ma
AU - Paul A. Selvadurai
AU - Virginie Durand
AU - Kavan Khaledi
AU - Mohammadreza Jalali
AU - Yousef Golabchi
AU - Sam Harris
AU - Alba Zappone
AU - Mathilde Wimez
AU - Marian Hertrich
AU - Stefan Wiemer
AU - Florian Amann
PY - 2026
DA - 2026/10/15
JO - Solid Earth
DO - 10.5194/se-17-1139-2026
UR - https://se.copernicus.org/articles/17/1139/2026/
AB - 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.
SN - 1869-9529
ER -