A coupled thermo-hydro-mechanical model for physically-based assessments of slope stability accounting for climate change

Project Information

SLOPETEMP

Grant agreement ID: 101033084

DOI

10.3030/101033084

Project closed

EC signature date 22 April 2021

Start date 1 October 2021

End date 30 November 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 156 980,64

EU contribution

€ 156 980,64

Coordinated by

UNIVERZITA KARLOVA
Czechia

Periodic Reporting for period 1 - SLOPETEMP (A coupled thermo-hydro-mechanical model for physically-based assessments of slope stability accounting for climate change)

Reporting period: 2021-10-01 to 2023-09-30

Summary of the context and overall objectives of the project

Problem/Issue Being Addressed: The primary issue addressed by this research is the inadequately recognized impact of temperature changes on slope stability, particularly in the context of climate change. Traditional models primarily consider hydrological factors like precipitation, overlooking the direct influence of thermal forcing on the mechanical behavior of soils. This oversight introduces significant uncertainties in landslide hazard assessments and slope stability evaluations.
Importance for Society: This research tackles a critical environmental challenge, enhancing our understanding of landslide mechanisms under changing climate conditions. Given the increased frequency of climate-induced geotechnical failures, the findings are vital for the safety of populations, infrastructure, and ecosystems in vulnerable regions. Improved predictive models are essential for developing more effective adaptation and mitigation strategies, aligning with EU climate adaptation policies and global risk management frameworks like the Sendai Framework.
Overall Objectives: The project aimed to develop and validate a novel coupled thermo-hydro-mechanical (THM) soil model. Objectives included demonstrating the applicability of this model to slope stability analyses under non-isothermal conditions, quantifying the effect of thermal forcing on slope stability through extensive parametric analyses, investigating real case studies to verify model performance, and conceptualizing a regional-scale model to enhance landslide risk assessments.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project spanned several phases, each aimed at addressing the overarching goal of incorporating thermal effects into slope stability assessments under climate change scenarios. Initial efforts focused on developing a conceptual framework for the thermo-hydro-mechanical (THM) model, based on the current developments on non-isothermal constative models and numerical tools capable of coupled THM simulation. This was followed by the numerical implementation of the model, using Code_Bright finite element software for robust simulation capabilities.
Key activities included: Literature Review and Conceptual Modeling: Comprehensive analysis of current models and identification of gaps in addressing thermal impacts on slope stability.
Model Development and Calibration: Design and calibration of the THM model to accurately simulate thermal, hydraulic, and mechanical soil behaviors.
In the project, a advanced non-isothermal viscoplastic model was developed to simulate the behavior of clays under conditions of heating and residual stress. This model was effectively implemented into a finite element program for Thermo-Hydro-Mechanical (THM) analysis of porous media, confirming its accuracy through numerical simulations that replicated experimental outcomes. Innovative mathematical expressions were introduced for strength parameters and stiffness characteristics associated with the hyperbolic yield surface, enhancing the model's predictive power. Additionally, this model was integrated as a constitutive law in the computer code, Code_Bright, bolstering its application in complex geotechnical simulations.
Further advancements were made by developing constitutive model for argillaceous hard soils and weak rocks to include non-isothermal conditions, aimed at improving THM simulations. The proposed thermo-elastoplastic model accounts for the effects of temperature on yield and plastic potential functions and on elastic stiffness, which was validated against non-isothermal laboratory tests documented in the literature.
Parametric Analysis: Execution of extensive simulations to assess the impact of various climate scenarios on slope stability.
Overview of Results Exploitation and Dissemination: Knowledge Transfer: Insights from the project have been incorporated into the host institution's curriculum and ongoing research activities, enhancing the educational and practical training of students and professionals in geotechnical engineering.
Tool Development: The THM model has been integrated into a suite of tools offered to engineers and policymakers for improved landslide risk assessment and management.
Dissemination: Publications: Results have been published in high-impact peer-reviewed journals, ensuring wide dissemination within the academic and professional communities. Key publications include articles in 'Géotechnique' and Geomechanics for Energy and the Environment'.
Conferences and Workshops: Findings were presented at major international conferences, including the 10th European Conference on Numerical Methods in Geotechnical Engineering, London, UK, 84th EAGE Annual Conference & Exhibition, Vienna, Austria, 17th Plinius Conference on Mediterranean Risks, Roma, Italy, EGU General Assembly 2022, Vienna, Austria, 2nd International Conference on Energy Geotechnics, CA, USA.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

This project has significantly advanced the state of the art in geotechnical modeling by developing a non-isothermal viscoplastic model specifically tailored to account for thermal effects in soil behavior under residual conditions. Prior models primarily focused on hydro-mechanical factors without adequately addressing the critical role of temperature changes. By integrating new mathematical formulations for strength parameters and stiffness in the hyperbolic yield surface, the project has enhanced predictive capabilities and accuracy in the simulation of THM behaviors. Furthermore, the adaptation of existing constitutive models to include non-isothermal conditions has set a new standard for the analysis of geo-energy systems impacted by temperature variations.
Results and Potential Impacts: Significant technical advancements were achieved, including the successful implementation and validation of the enhanced models in real-world settings. These results are expected to lead to improved risk assessments and engineering practices for infrastructures subjected to extreme thermal conditions, thereby enhancing safety and sustainability.
Socio-Economic Impact and Wider Societal Implications: The project's outcomes have substantial socio-economic impacts, particularly in enhancing the safety and efficiency of nuclear waste management—a critical issue given the global push for clean energy and the resulting need for sustainable waste disposal methods. The improved understanding of thermal effects on geological formations contributes directly to safer designs of underground storage facilities, reducing potential risks of contamination. Additionally, the project’s advancements provide valuable insights for civil engineering and disaster risk management, where accurate predictions of land stability under climate change scenarios are crucial.
The wider societal implications include raising awareness among policymakers and the public about the importance of integrating environmental changes into engineering and planning practices. By disseminating the findings through academic publications, presentations at international conferences, and public engagement initiatives, the project has contributed to a broader dialogue on climate resilience and sustainability in infrastructure development. This aligns with global efforts to mitigate the impacts of climate change on vulnerable communities and to promote public safety through scientifically informed decisions.

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