Project

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Future evolution of meta-stable rock slopes in hydropower systems of China: Implications for long-term safety

Applicant Lei Qinghua
Number 189882
Funding scheme Bilateral programmes
Research institution Departement Erdwissenschaften ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geology
Start/End 01.01.2020 - 31.12.2023
Approved amount 350'000.00
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All Disciplines (2)

Discipline
Geology
Civil Engineering

Keywords (7)

rock slope stability; hydropower system; long-term performance; rock mechanics; numerical modelling; field monitoring; remote sensing

Lay Summary (German)

Lead
Dieses Projekt untersucht das langfristige Verhalten von Felshängen bei Wasserkraftanlagen, die sich in kritischen Stabilitätszuständen befinden. Wir führen Überwachungen vor Ort, sowie Computersimulationen und Laborexperimente durch, um die künftige Entwicklung und Stabilität von Talflanken bei Talsperren besser vorhersagen zu können.
Lay summary

Während der letzten Jahrzehnte wurden in China viele grosse Wasserkraftanlagen mit sehr hohen Bogenstaumauern gebaut. Der Bau und der Betrieb dieser gigantischen Kraftwerke können die umgebenden Talflanken schwächen oder gar destabilisieren und so die Sicherheit der Wasserkraftanlagen und Bevölkerung gefährden. In diesem Projekt führen wir wissenschaftliche Untersuchungen zu denjenigen Mechanismen durch, die das langfristige Verhalten kritisch stabiler Felswände bei chinesischen Wasserkraftanlagen während der gesamten Lebensdauer der Wasserkraftwerke kontrollieren, und entwickeln neue Methoden zur Vorhersage ihrer zukünftigen Entwicklung. Wir führen Überwachungen vor Ort, sowie Computersimulationen und Laborexperimente durch um die natürlichen wie auch menschgemachten Prozesse zu verstehen, die zu irreversiblen Deformationen und fortschreitender Destablisierung dieser Felshänge führen. Unsere Forschung entspringt der Notwendigkeit, verbesserte Vorhersagen der zukünftigen Gefährdungen von Wasserkraftanlagen zu machen, da viele dieser Anlagen nun in den Betrieb gehen. Wir sehen dieses Projekt zudem als einzigartige Möglichkeit, die Erfahrungen der Schweizer Wissenschaftler und Ingenieure aus den europäischen Alpen auf Prozesse und Projekte in den Gebirgen Chinas zu übertragen.

Direct link to Lay Summary Last update: 20.12.2019

Lay Summary (English)

Lead
This project investigates the long-term behaviour of meta-stable rock slopes in hydropower systems in China. We carry out field monitoring, computer simulation and laboratory experiments to predict the future evolution of critical rock slopes.
Lay summary

Many large-scale hydropower systems utilising ultrahigh arch dams have been built in China over the past decades. The construction and operation of these giant power plants may perturb and destabilise the surrounding rock slopes, threatening the safety of hydropower systems and human habitats. In this project, we conduct scientific investigations into the mechanisms that govern the long-term behaviour of meta-stable rock slopes in Chinese hydropower systems and develop predictive approaches to forecast their future performance over the lifespan of hydropower plants. We carry out field monitoring, computer simulation and laboratory experiment to study the processes leading to irreversible deformation and progressive destabilisation of these rock slopes under natural and human activities. Our research stems from the urgent need for practitioners to have enhanced predictive capabilities regarding future geohazards in hydropower systems. This demand has recently come to the fore in China, where hydropower development has started to pass its rapid construction phase and shift to the lengthy operation stage. We also view this project as a uniquely situated stepping stone from which the Swiss researchers transfer related experiences gained from European Alps studies to the investigation of Earth’s surface processes in mountainous areas of China.

Direct link to Lay Summary Last update: 20.12.2019

Responsible applicant and co-applicants

Gesuchsteller/innen Ausland

Project partner

Abstract

Many large-scale hydropower systems involving ultrahigh arch dams seated in deep fluvial valleys have been developed in China over the past decades to meet the national electricity demand and energy systems transformation strategy. The construction and operation of these giant power plants impose significant perturbations to their surrounding meta-stable rock slopes that are subjected to an active and complex Earth’s surface environment and coupled seismo-hydro-mechanical processes. Some of these dams have already witnessed sustained deformations of abutment rock slopes and/or landslide motions of nearby mountain slopes, endangering the safety of hydropower systems and human habitats. Thus, it is of great importance to predict the future evolution of critically important meta-stable rock slopes in the widely spreading hydropower systems of China during the prolonged service lifetime of about hundred years.The objective of this project is to conduct fundamental scientific investigations into the mechanisms that govern the long-term behaviour of meta-stable rock slopes in hydropower circumstances and develop predictive approaches to forecast their future performance over the lifespan of hydropower systems. Our research aims to elucidate the multiscale and multiphysics processes leading to irreversible deformation and progressive destabilisation of these rock slopes under natural and anthropogenic activities. We will attempt to address four key research questions: (i) How do reservoir impoundment, water level fluctuations and earthquake cycles contribute to the development of irreversible deformation and internal damage in stable rock slopes? (ii) What damage/structural evolution is required for stable rock slopes to transition into unstable ones? (iii) How can the onset of accelerated slope creep and catastrophic failure be predicted? (iv) When and how will sustained deformation of abutment rock slopes threaten the operability and safety of hydropower dams? How can we identify hazardous rock slopes in hydropower reservoirs that are likely to fail catastrophically in the future? Based on a better understanding of the underlying mechanisms and an enhanced predictive capability of long-term rock slope behaviour, recommendations for monitoring and mitigating actions will be further provided.The strength of this joint proposal is highlighted by the complementary aspect of the Swiss and Chinese research teams, rendering a strong combination of expertise in geological and engineering sciences. The project will start with the development of an advanced multiscale and multiphysics computational platform for simulating temporal evolution of crystalline rock slopes and the characterisation of typical meta-stable rock slopes involved in Chinese ultrahigh arch dam systems. The numerical model will be successively extended, validated and calibrated for capturing the damage, deformation and destabilisation of rock slopes, supported by site-specific datasets from laboratory testing, field monitoring and remote sensing. The later phase of the project will develop a generalised assessment framework for evaluating long-term behaviour of meta-stable rock slopes in hydropower systems of China together with hazard mitigation strategies.
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