Experimental study on the effect of high stress cyclic loading on Kaiser effect in marble
SHI Kai1,MEI Fuding1,CHENG Mingsheng1,YANG Zhigang2,LUO Weibing3
(1. Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074,China;2. Tonglvshan Mine,Daye Nonferrous Metals Co.,Ltd.,Huangshi,Hubei 435000,China;3. Daye Nonferrous Metals Co.,Ltd.,Huangshi,Hubei 435000,China)
Abstract:Acoustic emission method(AE) is widely used in in-situ stress measurement. The cyclic loading method can be employed when the Kaiser effect is less pronounced in one cycle uniaxial compression test with AE monitoring. Usually,the peak stress of each cyclic loading is greater than the maximum stress that the rock ever experienced in the earth?s crust. To study the effect of the high stress on Kaiser effect of rock,cyclic loading test on marble specimens from the vertical drilling hole of Tonglushan mine was carried out. The take-off points in different loading cycles were determined according to the characteristics of AE curve and the results of in-situ stress measured with the methods of deformation rate analysis(DRA) and hydraulic fracturing. The results show that the high stress reduces the energy of AE events corresponding to ,diminishes the Kaiser effect in subsequent loading cycles and changes the magnitude of memorized stress in the rock at the same time. The repeated cyclic loading leads the destruction of rock?s internal microstructure,and the resulted AE obscures the take-off points. Besides,the high stress may replace and becomes the new stress memorized in the rock due to the differences of rock. In view of this,the peak loading stress of first cycle should not exceed ,and must make the specimen to enter the linear elastic stage. The reasonable range of the peak loading stress of first cycle is 6% to 28% of rock?s ultimate strength. In addition,the reasonable loading mode when AE and DRA method combined to measure geostress was given in the paper.
石 凯1,梅甫定1,程明胜1,杨志刚2,罗卫兵3. 循环加载高应力对大理岩Kaiser效应影响的试验研究[J]. 岩石力学与工程学报, 2017, 36(12): 2906-2916.
SHI Kai1,MEI Fuding1,CHENG Mingsheng1,YANG Zhigang2,LUO Weibing3. Experimental study on the effect of high stress cyclic loading on Kaiser effect in marble. , 2017, 36(12): 2906-2916.
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