HE Yongnian1,HAN Lijun1,ZHANG Houquan2,LIU Honggang1
(1. State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,
Xuzhou,Jiangsu 221116,China;2. School of Mechanics and Civil Engineering,China University of Mining and Technology,
Xuzhou,Jiangsu 221116,China)
Abstract:Rock splits due to the axial main compression load at the crack tip. This splitting is a compression tension failure,which is different from the compression shear failure of the Griffith theory. At the crack tip,there exists the extreme value of the minor tension stress. Tensile failure or splitting failure appear during the compression process corresponding to the gradual characteristics of rock failure. This kind of failure is beyond the modified Griffith theory. The criterion of the occurrence of rock splitting is that the value of longitudinal load should be high and the value of lateral stress should be low or zero and that there is no subsequent loads or the loads last short. The criterion was confirmed with the unloading test of thick-wall cylinder rock. Based on the energy principle,the energy dissipation characteristics of tension failure and compression failure was analyzed under no external work condition during the unload process,and the energy relations of rock failure were obtained. From the energy accumulation and dissipation,the mechanisms of coal-rock dynamic impacting and sudden damage of surrounding rock were revealed.
MCLINTOCK F A,WALSH J B. Friction on Griffith cracks in rocks under pressure[C]. In:Proc. 4th U. S. Nat. Congr. Appl. Mech.,Vol. II,Now York: Am. Soc. Mech. Eng. 1962:1 015-1 021
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