Congress report

Pre-coffee focus from engineers, geomorphologists, material scientists, and numerical modellers alike

PRF 2017 was a conference on Progressive Rock Failure (PRF) and time-dependent aspects of rock mass damage and strength degradation held from the 5^th – 9^th of June 2017  at Congressi Stefano Franscini in Ascona, Switzerland. Addressing these key challenges offered an excellent opportunity to bring together a range of participants from the rock mechanics, engineering geology, material sciences and geomorphology communities. In total we hosted 54 attendees from 37 separate institutions, with 30 attendees remaining to participate in a numerical modelling workshop held on the final day.

Geological materials change their strength properties through time, a condition which has significant implications for the stability of natural and artificial slopes, surface or subsurface excavations, and deep boreholes used for energy production. While some of these mechanical property changes lead to slow phenomena like creep, others lead to rapid and hazardous deformations and failure of geological materials. Time-dependent aspects of weakening and failure in natural systems are, however, difficult to study as internal damage is not visible to the naked eye, and the underlying processes can last from several seconds to many thousands of years. Better understanding and predicting these processes represents a great challenge to those involved in the preservation of critical transport and energy infrastructures, design and construction of nuclear waste repositories, and the assessment and mitigation of rockslope hazards in response to climatic drivers. By bringing together participants from diverse backgrounds, this event provided an exciting chance to address processes controlling the degradation and failure of brittle rock across an exceptional range of spatial and temporal scales.

Finally a sunny day. Time for PRF ‘surface’ people to get stuck into post-glacial fractures on the Gotthard.

The conference included three days of talks and discussions from international experts with one day of integrated field excursions, and a workshop on the practical implementation of PRF in numerical models on the final day. The conference was financially and logistically supported by ETH, the Swiss National Science Foundation (SNF), the Swiss Federal Nuclear Safety Inspectorate (ENSI), Schweizerische Fachgruppe für Ingenieurgeologie (SFIG), the International Society for Rock Mechanics (ISRM), and ITASCA Consulting Group Inc. Three field excursions were integrated into the middle of the week, visiting the Preonzo rock slope failure, the Schollenen Gorge and Sasso San Gotthardo on the Gotthard Pass, and the Bedretto Tunnel.

The oral programme was split into five sessions, with keynotes, field investigations, lab investigations, theory and conceptual modelling, state-of-the-art numerical modelling, and was closed out with an afternoon of working groups focussed on monitoring and modelling progressive failure, progressive failure in a changing climate, and safer infrastructure. It is envisaged that participants will contribute to a review article to be published in a top international journal. The numerical modelling workshop included topics covering micro-mechanical to practical engineering approaches to modelling time-dependent rock degradation, Continuum and discontinuum based approaches to simulate time-dependent processes, and Simulation of fracture initiation and propagation using Fracture Mechanics code FRACOD.

Two Early Career Scientist travel awards were awarded to Ms Anne Voigtländer, and Ms Chrysothemis Paraskevopoulou. The CSF Award for best young scientist presentation was awarded to Dr Odin Marc.

On behalf of the organizing committee, we’d like to thank all participants that made this a thoroughly successful event!