Key Takeaways & Executive Findings
- •• Thermal stress dominates crack initiation and propagation during thermal spalling. • Lateral constraints significantly delay and suppress spalling. • Material heterogeneity markedly influences peak stress and damage modes within a certain range of thermal expansion coefficient. • DGSA effectively quantifies parameter influence and interactions, identifying dominant controls on spalling onset, severity, and damage morphology.
Abstract
Thermal spalling in heterogeneous rocks under rapid heating poses critical risks to deep mining and geothermal operations. In this study, we develop a coupled thermal–mechanical–damage (TM-D) model that explicitly incorporates Weibull distributed heterogeneity to a single fracture in rock, and validate it against ceramic quenching and granite acoustic emission experiments. Distance based generalized sensitivity analysis (DGSA) is applied to quantify the influence and interactions of key parameters, revealing the dominant controls on spalling onset, severity, and damage morphology. The results demonstrate that thermal stress dominates crack initiation and propagation, that lateral constraints can significantly delay and suppress spalling, and that material heterogeneity markedly influences peak stress and damage modes within a certain range of thermal expansion coefficient and has multiple effects on thermal spalling. This study provides a theoretical basis for quantitative assessment and parameter optimization of thermal spalling processes in rock masses.
1. Introduction
Thermal spalling in heterogeneous rocks under rapid heating is a critical hazard in high temperature subsurface engineering, including deep mining, geothermal drilling, and underground fire scenarios [1,2]. Sudden temperature gradients induce complex thermal and mechanical stresses, often leading to rapid crack initiation and surface rupture. While previous studies have advanced thermal–mechanical–damage (TM-D) modeling, most assume material homogeneity and overlook microstructural variability and parameter interactions [3], limiting predictive accuracy and applicability across diverse rock types. Moreover the absence of standardized testing protocols impedes inter study comparisons [4,5]. This study addresses these gaps by integrating a TM-D coupling framework with Weibull distributed heterogeneity and applying distance based generalized sensitivity analysis (DGSA) to quantify the influence and coupling of key parameters.
Modeling thermal spallation in rocks demands an appropriate framework for TM-D coupling. Prior research [4,6] on deep mining induced rock failure has quantified deformation and damage patterns at specific high temperatures and geostress levels, defining yield-damage criteria for homogeneous rock. More recent three-dimensional simulations incorporate material heterogeneity and local degradation via mesoscale renormalization, employing a maximum tensile-stress criterion for tension and a Drucker-Prager criterion for shear failure [7,8]. Nevertheless, analyses of heterogeneous thermal spalling in rocks subjected simultaneously to extreme temperatures and high confining pressure remain scarce.
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Liyuan Liu, Mingshan Shi, Derek Elsworth, Tao Wang, Hongguang Ji, Le Zhang, Yaohui Li (2026). Coupled TM-damage modeling and global sensitivity analysis of thermal spalling in heterogeneous rocks. SinoTechIntel Verified Research. https://doi.org/10.1016/j.ijmst.2026.01.008
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Frequently Asked Questions
What is thermal spalling in rocks?
Thermal spalling is a phenomenon where rapid heating induces thermal stresses in rocks, leading to crack initiation and surface rupture. It is a critical hazard in high-temperature subsurface engineering such as deep mining and geothermal drilling.
How does material heterogeneity affect thermal spalling?
Material heterogeneity, modeled using Weibull distribution, significantly influences peak stress and damage modes. Within a certain range of thermal expansion coefficient, heterogeneity can alter the spalling behavior, showing multiple effects on the process.
What is DGSA and how is it used in this study?
DGSA (Distance-based Generalized Sensitivity Analysis) is a method to quantify the influence and interactions of model parameters. In this study, it is applied to identify dominant controls on spalling onset, severity, and damage morphology, revealing key parameter effects.
What are the practical implications of this research?
The findings provide a theoretical basis for quantitative assessment and parameter optimization of thermal spalling processes, aiding in the design of safer and more efficient deep mining and geothermal operations.
How was the coupled TM-D model validated?
The model was validated against ceramic quenching and granite acoustic emission experiments, ensuring its accuracy in predicting thermal spalling behavior.
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