Experimental and numerical analysis of Mode-I, Mode-II, and Mixed-Mode I/II fracture toughness in granite subjected to cryogenic and acidic treatments
Longinos S.N. Bulatova A.
June 2026Elsevier B.V.
Theoretical and Applied Fracture Mechanics
2026#144
The combined application of thermal stimulation and liquid nitrogen (LN2) has been proposed as an effective strategy to enhance hydraulic fracturing, which in turn improves the connectivity of geothermal reservoirs. To investigate how heat affects the Mode-I, Mode-II and mixed Mode I/II fracture behavior of granite, notched semi-circular bend (SCB) granite specimens were prepared and heat-treated at three different temperatures, ranging from 100 °C to 500 °C along with acidic environment (hydrochloric acid). Fracture energy decreases significantly (up to ∼92.5%) from room temperature to 500 °C depending on fracture mode and treatment intensity. The damage factor rises from 0.27 to 0.32 at 100 °C to 0.69–0.79 at 300–500 °C for Mode-I, Mode-II, and mixed-mode (45°) loading. The highest damage factor (0.91) occurs in mixed-mode I/II (30°) specimens at 500 °C, indicating severe structural degradation and irregular fracture propagation. Moderate thermal-cryogenic-chemical treatment (100 °C + LN2 + HCl) provides optimal conditions for controlled fracture propagation while promoting fracture toughness degradation. A phase-field damage framework was employed to simulate crack initiation and propagation and to support the interpretation of the experimental results. The numerical results were compared with experimental load-displacement curves to evaluate the predictive capability of the model. The results show that LN2-induced thermal shock dominates damage localization, while combined thermal-cryogenic-chemical treatment produces the highest degree of fracture asymmetry and degradation.
Fracture toughness , Fracturing , Granite , Liquid nitrogen
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Schulich School of Engineering, Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada
School of Mining and Geosciences, Department of Petroleum Engineering, Nazarbayev University, Astana, Kazakhstan
Schulich School of Engineering
School of Mining and Geosciences
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026