Abstract
Fracture toughness is used to characterize rock resistance to fracturing and it is important in theoretical research and engineering applications. Mode-I fracture toughness can be predicted on the basis of an empirical relationship between fracture toughness (KIC) and tensile strength (σt). In underground engineering, rocks are often subjected to different temperatures. Therefore, this paper explores the effect of temperature on the relationship between mode-I fracture toughness and tensile strength. The results show that the change trends in the KIC and σt values of rocks at temperatures from 20 °C to 600 °C are broadly consistent with each other. For rocks heat-treated to the same temperature, the KIC of the rock increases with an increase in σt. This positive correlation between KIC and σt is different in rocks heat-treated to different temperatures. Critical crack propagation radius (rIC) is an important factor in the relationship between KIC and σt and is related to the type of rock and the conditions under which it is tested. For the same rock, rIC is quite different after it has been exposed to different temperatures. The positive correlation between KIC and σt results from a similarity in the fracture morphology and properties of failure when rock is destroyed in fracture and tensile tests.
Highlights
Rock failure is very common in energy development engineering
Mode-I fracture toughness reached its highest value in the sample processed to 100 ◦ C, slightly higher than that kept at 20 ◦ C, indicating that heating to 100 ◦ C had a toughening effect and made the rock more able to resist fracture
The lowest mode-I fracture toughness in the temperature range below 500 ◦ C was at 500 ◦ C, when it was
Summary
Crack-formation is desirable, for instance in deep geothermal energy development where crack-formation in the artificial storage layer will increase the heat exchange area [1]. In such contexts, rock failure is conducive to improving the efficiency of energy extraction. In other engineering contexts, ensuring the stability and integrity of rock is essential to the smooth completion of the project. An example of this is in the rock surrounding underground coal gasification [2] or coal mining roadways [3]. Cracks play a key role in rock failure, so the problem of rock failure can be analyzed by way of fracture mechanics
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
