Fault reactivation induced by tunneling activity in clay material: Hints from numerical modeling
| Autor: | Antonio Pio Rinaldi, Luca Urpi |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Induced seismicity
0211 other engineering and technologies Geomechanical modeling 02 engineering and technology Slip (materials science) Fault (geology) 010502 geochemistry & geophysics 01 natural sciences Tunnel excavation Mining engineering Seismic risk Rock mass classification Quantum tunnelling 021101 geological & geomatics engineering 0105 earth and related environmental sciences geography geography.geographical_feature_category Fault reactivation Radioactive waste Excavation Building and Construction Geotechnical Engineering and Engineering Geology Geological nuclear repositories Geology |
| Zdroj: | Tunnelling and Underground Space Technology, 102 |
| ISSN: | 0886-7798 1878-4364 |
| DOI: | 10.1016/j.tust.2020.103453 |
| Popis: | Seismic events with magnitude 3 and above have been associated with the removal of rock mass in mining environment since long-time. On the contrary, little is known about the possible seismic events induced by tunneling, although it presents similarities with mining. One great example is the case of the 57 km long Gotthard Base Tunnel excavation, which has been associated more than hundred seismic events, with the largest one having magnitude of ML 2.4, damaging the tunnel infrastructures (e.g. gallery floor or portal area). Different underground structures will be built probably up to 1000 m below ground for the construction of future deep geological for the storage of nuclear waste. While seismic risk will probably not constitute a liability for the storage site construction, it is important to understand the potential for reactivation of seismogenic features located nearby the future location of emplacement tunnels. Here we present numerical simulations aimed at understanding the potential for fault reactivation during tunnel construction in clay material, a potential host rock for nuclear waste repository. We evaluate the evolution of the stress changes during the simulation of the excavation with FLAC3D numerical solver. A strain-softening friction model is used to simulate the occurrence of a sudden slip on a fault zone when critical conditions for reactivation are satisfied. This constitutes a worst-case scenario, given the low seismogenic potential of clay rocks. We also present a sensitivity analysis on several critical parameters including fault frictional properties, stress conditions, as well as different tunnel sizes at varying distance from a nearby failure plane, with the final purpose of evaluating safety of a potential nuclear repository site on the short- and long-term. Tunnelling and Underground Space Technology, 102 ISSN:0886-7798 ISSN:1878-4364 |
| Databáze: | OpenAIRE |
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