Investigation into biaxial mechanical behaviour of coalmine sandstone with a new loading apparatus
As mining activities continue to reach deeper deposits,mining-induced stresses at underground mine fronts can be significant enough to cause rock failure,or even rockburst. The state of stress at the boundary of mine fronts is that of plane stress. For investigating the biaxial strength of geomaterials,a series of tests on 75 and 100mm cube gray sandstone samples,obtained from an underground coal mining operation in China has been carried out for the purpose of determining the biaxial strength characteristics of the sandstone rock. Tests were performed under biaxial loading condition and the samples were subjected to a loading rate of 1 MPa/s. Both uniaxial and triaxial compression tests were also performed on cubic and traditional cylindrical samples and the results were compared. Two loading paths were adopted-the first with equal loading in both directions until failure,and the second with equal loading in both directions until 50％ of the uniaxial compressive strength is attained,followed by loading in one direction to failure while holding the other constant. Test results and observed phenomena are reported,and failure mechanisms due to biaxial loading are discussed. It is observed that the biaxial strength is significantly increased with lateral confinement. The failure mechanism is generally initiated by rock spalling at the free faces of the rock sample when σ1 and σ2 have surpassed the σc/2 region,and that spalling continue as loading increases. The ultimate failure occurs in the form of an out-of-plane shear failure mechanism and is of violent nature.
Sandstone Rock testing biaxial compression rock failure
Yun Xiaoyou Mitri Hani Yang Xiaolin
Department of Mining and Materials Engineering,McGill University,Montreal,Canada Luoyang Institute of Science and Technology,Luoyang,China
国际会议
北京
英文
570-580
2008-10-20（万方平台首次上网日期，不代表论文的发表时间）