Deformation and Failure Mechanism of Phyllite under the Effects of THM Coupling and Unloading

• Published in: Journal of mountain science 2012-12, Vol.9 (6), p.788-797
• Main Authors: Meng, Lubo, Li, Tianbin, Xu, Jin, Chen, Guoqing, Ma, Hongming, Yin, Hongyu
• Format: Article
• Language: English
• Subjects: Deformation; Earth and Environmental Science; Earth Sciences; Ecology; Environment; Failure analysis; Geography; High temperature; Load; Mechanics; Permeability; Poisson's ratio; Pore water; Rocks; THM; Water pressure; 初始磁导率; 千枚岩; 卸载条件; 变形破坏机制; 孔隙水压力; 弹性模量; 耦合模型
• ISSN: 1672-6316; 1993-0321; 1008-2786
• DOI: 10.1007/s11629-012-2286-9

Although the study of TM（Thermo Mechanics）,HM（Hydraulic-Mechanics） and THM（Thermo-Hydraulic-Mechanics） coupling under a loading test have been under development,rock failure analysis under THM coupling and unloading is an emerging topic.Based on a high temperature triaxial unloading seep test for phyllite,this paper discusses the deformation and failure mechanism of phyllites under the ＂H M,T→H,T→M＂ incomplete coupling model with unloading conditions.The results indicate that the elastic modulus and initial permeability decrease and the Poisson＇s ratio increases with increasing temperature;the elastic modulus decreases and the Poisson＇s ratio and initial permeability increase with increasing water pressure.During the unloading process,rock penetrability is small at the initial elastic deformation phase,but the penetrability increases near the end of the elastic deformation phase;mechanisms involving temperature and water pressure affect penetrability differently.Phyllite failure occurs from the initial thermal damage of the rock materials,splitting and softening（which is caused by pore water pressure）,and the pressure difference which is formed from the loading axial pressure and unloading confining pressure.The phyllite failure mechanism is a transtensional（tension-shearing） failure.