In the heart of Shanghai, researchers at Tongji University have made a significant stride in understanding how heat affects the stability of bedding rocks, a critical concern for industries like geothermal energy and nuclear waste storage. Led by Dr. Zhang Chengkai from the College of Civil Engineering and the State Key Laboratory of Disaster Reduction in Civil Engineering, the team has developed a sophisticated model to predict how these rocks fracture under thermal stress, considering their inherent anisotropic properties.
The study, published in *Yantu gongcheng xuebao* (translated to *Rock and Soil Mechanics*), introduces a phase-field model that incorporates transversely isotropic constitutive and structural tensors. This model allows engineers to simulate and understand the complex behavior of bedding rocks when subjected to thermal loads. “Our model provides a more accurate representation of how cracks initiate and propagate in these rocks, considering their directional properties,” explains Dr. Zhang. This is particularly important for industries dealing with heat-affected structures, such as geothermal mining and nuclear waste repositories.
The team validated their model through comparisons with analytical solutions, numerical simulations, and experimental data, ensuring its reliability in capturing both dynamic and quasi-static thermal fracture behaviors. Their findings reveal that variations in four thermal parameters—stiffness, critical fracture energy, thermal expansion coefficient, and thermal conductivity—significantly influence crack propagation morphology. Notably, the thermal expansion coefficient was found to have the most substantial impact on crack propagation, followed by mechanical parameters, with thermal conductivity having the least influence.
For the energy sector, these insights are invaluable. Geothermal energy, which harnesses heat from the Earth’s crust, often involves drilling into bedding rock formations. Understanding how these rocks behave under thermal stress can help prevent costly and dangerous fractures, ensuring the stability and safety of geothermal power plants. Similarly, in nuclear waste storage, where heat generated by radioactive decay can induce fractures in the surrounding rock, this research provides crucial guidance for designing effective crack-arrest measures.
Dr. Zhang highlights the practical implications of their work: “By understanding how these parameters affect crack propagation, we can better design and implement measures to mitigate fractures in geotechnical engineering projects involving heat-affected bedding structures.” This research not only advances our scientific understanding but also offers practical solutions for industries grappling with thermal-induced fractures in anisotropic rocks.
As the energy sector continues to evolve, the need for accurate modeling and prediction of rock behavior under thermal stress becomes increasingly important. This research from Tongji University paves the way for more robust and reliable engineering practices, ensuring the safety and efficiency of geothermal and nuclear waste storage projects. With further development, such models could become standard tools in the geotechnical engineer’s toolkit, shaping the future of energy infrastructure.