Strength degradation of sandstone and granodiorite under uniaxial cyclic loading
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摘要
Change in mechanical properties of rocks under static loading has been widely studied and documented.However, the response of rocks to cyclic loads is still a much-debated topic. Fatigue is the phenomenon when rocks under cyclic loading fail at much lower strength as compared to those subjected to the monotonic loading conditions. A few selected cored granodiorite and sandstone specimens have been subjected to uniaxial cyclic compression tests to obtain the unconfined fatigue strength and life. This study seeks to examine the effects of cyclic loading conditions, loading amplitude and applied stress level on the fatigue life of sandstone, as a soft rock, and granodiorite, as a hard rock, under uniaxial compression test. One aim of this study is to determine which of the loading conditions has a stronger effect on rock fatigue response. The fatigue response of hard rocks and soft rocks is also compared. It is shown that the loading amplitude is the most important factor affecting the cyclic response of the tested rocks. The more the loading amplitude, the shorter the fatigue life, and the greater the strength degradation. The granodiorite specimens showed more strength degradation compared to the sandstone specimens when subjected to cyclic loading. It is shown that failure modes of specimens under cyclic loadings are different from those under static loadings. More local cracks were observed under cyclic loadings especially for granodiorite rock specimens.
Change in mechanical properties of rocks under static loading has been widely studied and documented.However, the response of rocks to cyclic loads is still a much-debated topic. Fatigue is the phenomenon when rocks under cyclic loading fail at much lower strength as compared to those subjected to the monotonic loading conditions. A few selected cored granodiorite and sandstone specimens have been subjected to uniaxial cyclic compression tests to obtain the unconfined fatigue strength and life. This study seeks to examine the effects of cyclic loading conditions, loading amplitude and applied stress level on the fatigue life of sandstone, as a soft rock, and granodiorite, as a hard rock, under uniaxial compression test. One aim of this study is to determine which of the loading conditions has a stronger effect on rock fatigue response. The fatigue response of hard rocks and soft rocks is also compared. It is shown that the loading amplitude is the most important factor affecting the cyclic response of the tested rocks. The more the loading amplitude, the shorter the fatigue life, and the greater the strength degradation. The granodiorite specimens showed more strength degradation compared to the sandstone specimens when subjected to cyclic loading. It is shown that failure modes of specimens under cyclic loadings are different from those under static loadings. More local cracks were observed under cyclic loadings especially for granodiorite rock specimens.
Change in mechanical properties of rocks under static loading has been widely studied and documented.However, the response of rocks to cyclic loads is still a much-debated topic. Fatigue is the phenomenon when rocks under cyclic loading fail at much lower strength as compared to those subjected to the monotonic loading conditions. A few selected cored granodiorite and sandstone specimens have been subjected to uniaxial cyclic compression tests to obtain the unconfined fatigue strength and life. This study seeks to examine the effects of cyclic loading conditions, loading amplitude and applied stress level on the fatigue life of sandstone, as a soft rock, and granodiorite, as a hard rock, under uniaxial compression test. One aim of this study is to determine which of the loading conditions has a stronger effect on rock fatigue response. The fatigue response of hard rocks and soft rocks is also compared. It is shown that the loading amplitude is the most important factor affecting the cyclic response of the tested rocks. The more the loading amplitude, the shorter the fatigue life, and the greater the strength degradation. The granodiorite specimens showed more strength degradation compared to the sandstone specimens when subjected to cyclic loading. It is shown that failure modes of specimens under cyclic loadings are different from those under static loadings. More local cracks were observed under cyclic loadings especially for granodiorite rock specimens.
引文
Attewell PB,Farmer IW.Fatigue behaviour of rock.International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts 1973;10(1):1-9.
Bagde MN,Petros V.Fatigue properties of intact sandstone samples subjected to dynamic uniaxial cyclical loading.International Journal of Rock Mechanics and Mining Sciences 2005a;42(2):237-50.
Bagde MN,Petros V.The effect of machine behaviour and mechanical properties of intact sandstone under static and dynamic uniaxial cyclic loading.Rock Mechanics and Rock Engineering 2005b;38(1):59-67.
Bagde MN,Petros V.Waveform effect on fatigue properties of intact sandstone in uniaxial cyclical loading.Rock Mechanics and Rock Engineering 2005c;38(3):169-96.
Bagde MN,Petros V.Fatigue and dynamic energy behaviour of rock subjected to cyclical loading.International Journal of Rock Mechanics and Mining Sciences2009;46(1):200-9.
Bastian T,Connelly B,Lazo Olivares C,Yfantidis N,Taheri A.Progressive damage of Hawkesbury sandstone subjected to systematic cyclic loading.Journal of Research Projects Review 2014;3(1):7-14.
Burdine NT,Rock failure under dynamic loading conditions.Society of Petroleum Engineers Journal 1963;3(1).https://doi.org/10.2118/481-PA.
Eberhardt E.Brittle rock fracture and progressive damage in uniaxial compression.PhD Thesis.Saskatoon,Canada:University of Saskatchewan;1998.
Eberhardt E,Stead D,Stimpson B,Read RS.Identifying crack initiation and propagation thresholds in brittle rock.Canadian Geotechnical Journal 1998;35(2):222-33.
Ghazvinian E.Fracture initiation and propagation in low porosity crystalline rocks:implications for excavation damage zone(EDZ)mechanics.PhD Thesis.Kingston,Ontario,Canada:Queen's University;2015.
Gong M,Smith I.Effect of waveform and loading sequence on low-cycle compressive fatigue life of spruce.Journal of Materials in Civil Engineering2003;15(1):93-9.
He MM,Li N,Chen YS,Zhu CH.Strength and fatigue properties of sandstone under dynamic cyclic loading.Shock and Vibration 2016.https://doi.org/10.1155/2016/9458582.
Liu EL,He SM,Xue XH,Xu J.Dynamic properties of intact rock samples subjected to cyclic loading under confining pressure conditions.Rock Mechanics and Rock Engineering 2011;44(5):629-34.
Liu EL,Huang RQ,He SM.Effects of frequency on the dynamic properties of intact rock samples subjected to cyclic loading under confining pressure conditions.Rock Mechanics and Rock Engineering 2012;45(1):89-102.
Momeni A,Karakus M,Khanlari GR,Heidari M.Effects of cyclic loading on the mechanical properties of a granite.International Journal of Rock Mechanics and Mining Sciences 2015;77:89-96.
Prost GL Jointing at rock contacts in cyclic loading.International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts 1988;25(5):263-72.
Ray SK,Sarkar M,Singh TN.Effect of cyclic loading and strain rate on the mechanical behaviour of sandstone.International Journal of Rock Mechanics and Mining Sciences 1999;36(4):543-9.
Singh SK.Fatigue and strain hardening behaviour of graywacke from the flagstaff formation,New South Wales.Engineering Geology 1989;26(2):171-9.
Taheri A,Yfantidis N,Olivares C,Connelly B,Bastian T.Experimental study on degradation of mechanical properties of sandstone under different cyclic loadings.Geotechnical Testing Journal 2016;39(4):673-87.
Tao ZY,Mo HH.An experimental study and analysis of the behaviour of rock under cyclic loading.International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts 1990;27(1):51-6.
Wang Z,Li S,Qiao L,Zhao J.Fatigue behavior of granite subjected to cyclic loading under triaxial compression condition.Rock Mechanics and Rock Engineering2013;46(6):1603-15.
Xiao JQ,Ding DX,Jiang FL,Xu G.Fatigue damage variable and evolution of rock subjected to cyclic loading.International Journal of Rock Mechanics and Mining Sciences 2010;47(3):461-8.
Xiao JQ,Ding DX,Xu G,Jiang FL Waveform effect on quasi-dynamic loading condition and the mechanical properties of brittle materials.International Journal of Rock Mechanics and Mining Sciences 2008;45(4):621-6.
Xiao JQ,Ding DX,Xu G,Jiang FL Inverted S-shaped model for nonlinear fatigue damage of rock.International Journal of Rock Mechanics and Mining Sciences2009;46(3):643-8.
Yang SQ,Ranjith PG,Huang YH,Yin PF,Jing HW,Gui YL,Yu QL Experimental investigation on mechanical damage characteristics of sandstone under triaxial cyclic loading.Geophysical Journal International 2015;201(2):662-82.
Bagde MN,Petros V.Fatigue properties of intact sandstone samples subjected to dynamic uniaxial cyclical loading.International Journal of Rock Mechanics and Mining Sciences 2005a;42(2):237-50.
Bagde MN,Petros V.The effect of machine behaviour and mechanical properties of intact sandstone under static and dynamic uniaxial cyclic loading.Rock Mechanics and Rock Engineering 2005b;38(1):59-67.
Bagde MN,Petros V.Waveform effect on fatigue properties of intact sandstone in uniaxial cyclical loading.Rock Mechanics and Rock Engineering 2005c;38(3):169-96.
Bagde MN,Petros V.Fatigue and dynamic energy behaviour of rock subjected to cyclical loading.International Journal of Rock Mechanics and Mining Sciences2009;46(1):200-9.
Bastian T,Connelly B,Lazo Olivares C,Yfantidis N,Taheri A.Progressive damage of Hawkesbury sandstone subjected to systematic cyclic loading.Journal of Research Projects Review 2014;3(1):7-14.
Burdine NT,Rock failure under dynamic loading conditions.Society of Petroleum Engineers Journal 1963;3(1).https://doi.org/10.2118/481-PA.
Eberhardt E.Brittle rock fracture and progressive damage in uniaxial compression.PhD Thesis.Saskatoon,Canada:University of Saskatchewan;1998.
Eberhardt E,Stead D,Stimpson B,Read RS.Identifying crack initiation and propagation thresholds in brittle rock.Canadian Geotechnical Journal 1998;35(2):222-33.
Ghazvinian E.Fracture initiation and propagation in low porosity crystalline rocks:implications for excavation damage zone(EDZ)mechanics.PhD Thesis.Kingston,Ontario,Canada:Queen's University;2015.
Gong M,Smith I.Effect of waveform and loading sequence on low-cycle compressive fatigue life of spruce.Journal of Materials in Civil Engineering2003;15(1):93-9.
He MM,Li N,Chen YS,Zhu CH.Strength and fatigue properties of sandstone under dynamic cyclic loading.Shock and Vibration 2016.https://doi.org/10.1155/2016/9458582.
Liu EL,He SM,Xue XH,Xu J.Dynamic properties of intact rock samples subjected to cyclic loading under confining pressure conditions.Rock Mechanics and Rock Engineering 2011;44(5):629-34.
Liu EL,Huang RQ,He SM.Effects of frequency on the dynamic properties of intact rock samples subjected to cyclic loading under confining pressure conditions.Rock Mechanics and Rock Engineering 2012;45(1):89-102.
Momeni A,Karakus M,Khanlari GR,Heidari M.Effects of cyclic loading on the mechanical properties of a granite.International Journal of Rock Mechanics and Mining Sciences 2015;77:89-96.
Prost GL Jointing at rock contacts in cyclic loading.International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts 1988;25(5):263-72.
Ray SK,Sarkar M,Singh TN.Effect of cyclic loading and strain rate on the mechanical behaviour of sandstone.International Journal of Rock Mechanics and Mining Sciences 1999;36(4):543-9.
Singh SK.Fatigue and strain hardening behaviour of graywacke from the flagstaff formation,New South Wales.Engineering Geology 1989;26(2):171-9.
Taheri A,Yfantidis N,Olivares C,Connelly B,Bastian T.Experimental study on degradation of mechanical properties of sandstone under different cyclic loadings.Geotechnical Testing Journal 2016;39(4):673-87.
Tao ZY,Mo HH.An experimental study and analysis of the behaviour of rock under cyclic loading.International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts 1990;27(1):51-6.
Wang Z,Li S,Qiao L,Zhao J.Fatigue behavior of granite subjected to cyclic loading under triaxial compression condition.Rock Mechanics and Rock Engineering2013;46(6):1603-15.
Xiao JQ,Ding DX,Jiang FL,Xu G.Fatigue damage variable and evolution of rock subjected to cyclic loading.International Journal of Rock Mechanics and Mining Sciences 2010;47(3):461-8.
Xiao JQ,Ding DX,Xu G,Jiang FL Waveform effect on quasi-dynamic loading condition and the mechanical properties of brittle materials.International Journal of Rock Mechanics and Mining Sciences 2008;45(4):621-6.
Xiao JQ,Ding DX,Xu G,Jiang FL Inverted S-shaped model for nonlinear fatigue damage of rock.International Journal of Rock Mechanics and Mining Sciences2009;46(3):643-8.
Yang SQ,Ranjith PG,Huang YH,Yin PF,Jing HW,Gui YL,Yu QL Experimental investigation on mechanical damage characteristics of sandstone under triaxial cyclic loading.Geophysical Journal International 2015;201(2):662-82.