Crack growth time dependence analysis of granite under compressive-shear stresses state

• Published in: Journal of coal science & engineering, China Vol. 14; no. 1; pp. 34 - 37
• Main Author: 李江腾 曹平 古德生 吴超
• Format: Journal Article
• Language: English
• Published: Heidelberg China Coal Society 01.03.2008
• Subjects: Earth and Environmental Science; Earth Sciences; Geochemistry; Geology; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Mechanical Engineering; 应激状态; 开采技术; 花岗岩; 裂纹发展; time dependence; crack stability growth; limit time; granite; compressive-shear stresses state
• ISSN: 1006-9097; 1866-6566
• DOI: 10.1007/s12404-008-0007-3

The curves of crack relative length lib and crack growth time t of granite were gained under compressive stresses state according to subcritical crack growth parameters and crack stability growth equation by double-torsion constant displacement load relaxa- tion method. The relations between crack relative length and the crack growth time were discussed under different stresses and different crack lengths. The results show that there is a turning point on curve of crack relative length lib and crack growth time of granite. The slope of curve is small when crack relative length is less than the vertical coordinate of the point, and crack grows stably in this case. Cracks grow, encounter and integrate catastro- phically when crack relative length is more than the vertical coordinate of the point, and there is not a gradual stage from crack stability growth to crack instability growth, i.e. rock mass instability is sudden. The curves of crack relative length lib and crack growth time t of granite move to right with decrease of stress σl or crack length a, which implies that limit time increases consequently. The results correspond to practicality.