Work

Study on the Effect of High Temperature and Cyclic Loading and Unloading Methods on the Mechanical Properties of Granite

Year: 2025

Type: article

Abstract: During the formation of deep rock bodies, such as hot dry rock, they are frequently exposed to high temperatures and repeated stress perturbations. The prolonged interaction of these two factors is a potential cause of deep underground rock instability. To investigate the effects of high temperature and cyclic loading–unloading modes on rock mechanical properties, cyclic tests were conducted on granite under real-time high-temperature conditions using a multifunctional high-temperature testing machine. By comparing uniaxial compression test results with scanning electron microscopy (SEM) observations, the following was found: (1) The uniaxial compressive strength and elastic modulus of granite under real-time high-temperature conditions initially increase and then decrease as the temperature rises, while the peak strain consistently increases with temperature. (2) Under both cyclic loading–unloading modes, the mechanical properties of granite first improve and then deteriorate as the temperature increases. (3) As the temperature rises, microcracks in granite under both cyclic loading–unloading methods evolve from intracrystalline to intergranular cracks. The fracture surfaces of granite exhibit a significant increase in fracture severity, along with a noticeable rise in both the number and width of cracks. Crack propagation and crystal integrity degradation are more severe and complex in specimens subjected to variable lower limit cyclic loading–unloading than in those under constant-limit cyclic loading–unloading. These findings are of significant theoretical value for studying rock stability under simultaneous high-temperature and cyclic stress conditions.

Source: Applied Sciences

DOI: 10.3390/app15084448

Authors: Fan Zhang, Congcong Lv, Kangwen Li, Yiming Zhang, Shengyuan Liu, Man Li

Institution: Hubei University of Technology

Language: English

Topic: Rock Mechanics and Modeling

Subfield: Mechanics of Materials

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,896

Funder: National Natural Science Foundation of China