Thermo- and hydro-mechanical monitoring and modeling of jointed ROCKs: a national Site Laboratory network

Abstract

THEROCKLAB focuses on the study of thermo- and hydro-mechanical processes affecting fractured rock masses, through multisensor monitoring and modeling approaches. A national network of small-scale potentially unstable rock compartments, monitored with a common integrated methodology, is established within the project. The selected rock masses are exploited as site laboratories to assess the predisposition to failure linked to the natural meteorogical and climatic forcing. The five field labs are located along the Alps and the Apennines to maximize the variety of geo-structural settings potentially prone to instability and the possible environmental and climatic conditions. The four research units involved in the project (POLITO, UNIBO, UNIROMA1, UNIMIB) carry different expertise and methodological approaches to the monitoring and modeling of unstable rock masses. Their experience is integrated in THEROCKLAB for the design, instrumentation, long-term continuous monitoring of a new site lab located in the periglacial environment and affected by permafrost degradation. The integrated methodology developed within the project mainly involves continuous passive seismic and geomechanical monitoring, coupled with remote sensing techniques. Data collected at the different site lab are then integrated and interpreted as a function of the external meteorological and climatic conditions, with a special focus on air temperature and precipitation effects on site stability. The selection of a site lab located in an abandoned quarry makes experiments in forced thermal and vibrational conditions feasible within the project. These test allow for exploring the evolution of mechanical properties until the final collapse in comparison with natural forcing conditions, for early warning perspectives. Similar tests, including freezing-thawing cycles, are carried out at the laboratory scale on intact and fractured rock blocks and a continuous monitoring of deformations and seismic parameters during the experiments. The lab scale is used as a proxy to improve the understanding of the correlation between rock mass quality and susceptibility to damage due to thermal and hydrogeological drivers at the field scale. Both lab and field scales make extensive use of numerical modeling for a deeper understanding and quantification of the recorded thermo- and hydro-mechanical processes and to forecast possible field instabilities. THEROCKLAB final aim is to define standard procedures for a multi-scale characterization, monitoring and modeling of hydro- and thermo-mechanical effects on fractured rock masses to promote the spread of diffuse monitoring and prevention of natural hazards.

Team di ricerca UNIBO

Davide Donati , Alberto Landuzzi

Partner di progetto

Politecnico di Torino, Università La Sapienza, Università di Milano Bicocca