Microscopic Damage Evolution and Failure Mechanisms of Rocks with Different Mineral Compositions Under Thermal-Mechanical Loading
Year: 2026
Type: article
Abstract: This study investigated the evolution of mineral contacts and cracks in granite and sandstone subjected to high-temperature damage. To represent the heterogeneous strength distribution and random failure of rock micro-elements, a PFC damage contact model was developed by introducing a two-parameter Weibull strength distribution into particle contacts. A temperature-dependent damage coefficient was further incorporated into the failure criterion to describe the stress–strain response under coupled thermo-mechanical loading. The numerical results agree well with the experimental mechanical parameters, with errors in elastic modulus and peak strength below 5%. The proposed model effectively captures the elastic stage, peak response, post-peak softening behaviour, and damage evolution of the rocks, while the simulated failure modes are consistent with the observed damage characteristics. Statistical analysis of microcrack evolution and effective mineral contacts further explains the macroscopic failure mechanisms of feldspar-dominated granite and quartz-dominated sandstone. The results indicate that, under high temperatures up to 600 °C for sandstone and 400 °C for granite, sandstone cracks are mainly induced by thermal expansion, whereas granite cracks are related to reduced crystal spacing during cooling. Without lateral constraint, sandstone experiences relatively limited thermal damage, while granite develops more cracks due to thermal stress. Confining pressure improves sandstone strength but has limited influence on granite because inter-mineral microcracks are largely irreversible. At room temperature, mineral grain failure mainly occurs horizontally, whereas high temperature causes sandstone failure to shift obliquely. Granite develops multidirectional cracks due to local stress concentration.
Source: Rock Mechanics Bulletin
Language: English
Topic: Rock Mechanics and Modeling
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7203587990