单轴压缩荷载下含黏结面花岗岩能量演化研究
|
摘要
为探究能量演化在含黏结面不完整岩石受载过程中的规律,选取带有矿物质黏结斜面的花岗岩进行单轴循环加卸载压缩试验,同时在试验过程中进行声发射检测.得到以下结论:"有效能比"(累积弹性能/输入岩石的总能)可以作为岩石储能水平的表征,也可间接反映岩石内部结构随应力状态的改变;从整个加载过程来看,黏结面部位破坏的声发射释能短促、强烈,峰值强度时声发射持续时间较长,但声发射释能率相比黏结面破坏时较低;应力水平较低时,卸载过程中一般不会有声发射现象或声发射现象基本可以忽略,但当应力水平达到一定值时,即花岗岩积聚的弹性能超过了黏结面部位破坏的耗散能时,花岗岩在卸载时会发生短促、强烈的脆性破坏;由于声发射能量属于耗散能的一部分,定义"声发射检测效率"(声发射累积能量/累积耗散能),对于本次试验对象而言,"声发射检测效率"在压密阶段降低,弹性阶段升高,黏结面局部破坏时达到峰值,之后直至峰值强度该值呈现持续降低趋势;从能量角度分析,卸载破裂所对应的应力水平低于加载强度,但不应低于与峰值强度时耗散能大小相等的弹性能所对应的应力水平.
To investigate the regularity of energy evolution in the process of rock loading with imperfect bounding surface,uniaxial cyclic loading and unloading compressive tests were conducted on granite with mineral bonding slope,during which its acoustic emission was detected. It concludes that: 1) The " Effective energy ratio "( defined as cumulative elastic energy/input rock total energy) can be used as a token of rock energy storage level,which can also indirectly reflect the internal structure of the rock as the stress state changes. 2) The test object's acoustic emission energy release rate at the bonding surface of the test object was higher than that at peak intensity during the loading process. Acoustic emission at the site of bond surface release was short and strong,and the duration of acoustic emission at peak intensity was long but the acoustic emission and energy release rate was lower than that at bond surface failure. 3) No acoustic emission phenomenon occurred in the unloading process with low stress level or such phenomenon could be ignored. However,when the stress reached a certain level,where the elastic energy of granite accumulation exceeded the dissipation energy of local damage,short and intense brittle failure occurred during unloading. 4) The " AE detection efficiency"( cumulative AE/cumulative dissipation energy) is defined based on the fact that AE energy is part of the dissipative energy. It was found that " AE detection efficiency" decreased during the compaction phase and increased in the elastic phase. It reached peak value when the bonding surface was partially destroyed. After that,it tended to decrease until the peak intensity of bonding surface was reached. 5) From the energy point of view,the stress level corresponding to unloading rupture is lower than the loading strength,but it should not be lower than the stress level corresponding to the elastic energy which is equal to the dissipation energy at peak intensity.
To investigate the regularity of energy evolution in the process of rock loading with imperfect bounding surface,uniaxial cyclic loading and unloading compressive tests were conducted on granite with mineral bonding slope,during which its acoustic emission was detected. It concludes that: 1) The " Effective energy ratio "( defined as cumulative elastic energy/input rock total energy) can be used as a token of rock energy storage level,which can also indirectly reflect the internal structure of the rock as the stress state changes. 2) The test object's acoustic emission energy release rate at the bonding surface of the test object was higher than that at peak intensity during the loading process. Acoustic emission at the site of bond surface release was short and strong,and the duration of acoustic emission at peak intensity was long but the acoustic emission and energy release rate was lower than that at bond surface failure. 3) No acoustic emission phenomenon occurred in the unloading process with low stress level or such phenomenon could be ignored. However,when the stress reached a certain level,where the elastic energy of granite accumulation exceeded the dissipation energy of local damage,short and intense brittle failure occurred during unloading. 4) The " AE detection efficiency"( cumulative AE/cumulative dissipation energy) is defined based on the fact that AE energy is part of the dissipative energy. It was found that " AE detection efficiency" decreased during the compaction phase and increased in the elastic phase. It reached peak value when the bonding surface was partially destroyed. After that,it tended to decrease until the peak intensity of bonding surface was reached. 5) From the energy point of view,the stress level corresponding to unloading rupture is lower than the loading strength,but it should not be lower than the stress level corresponding to the elastic energy which is equal to the dissipation energy at peak intensity.
引文
[1]谢和平,鞠杨,黎立云,等.岩体变形破坏过程的能量机制[J].岩石力学与工程学报,2008,27(9):1729-1740.XIE Heping,JU Yang,LI Liyun,et al.Energy mechanism of deformation and failure of rocks[J].Chin J of Rock Mech Eng,2008,27(9):1729-1740.
[2]BA ZˇANTZ P.Analysis of work-of-fracture method for measuring fracture energy of concrete[J].Journal of Engineering Mechanics,1996,122(2):138-144.DOI:10.1061/(ASCE)0733-9399(1996)122:2(138).
[3]HAMIEL Y,LYAKHOVSKY V,BEN-ZION Y.The elastic strain energy of damaged solids with applications to non-Linear deformation of crystalline rocks[J].Pure and Applied Geophysics,2011,168(12):2199-2210.
[4]CATES M E,WITTMER J P,BOUCHAUD J P,et al.Jamming force chains and fragile matter[J].Phys Rev Lett,1998,81(9):1841-1844.
[5]DAVIES T R H,MCSAVENEY M J,BOULTON C J.Elastic strain energy release from fragmenting grains:Effects on fault rupture[J].Journal of Structural Geology,2012,38(5):265-277.DOI:10.1016/j.jsg.2011.11.004.
[6]HAZZARD J F,YOUNG R P,MAXWELL S C.Micromechanical modeling of cracking and failure in brittle rocks[J].Journal of Geophysical Research Solid Earth,2000,105(B7):16683-16697.DOI:10.1029/2000JB900085.
[7]GAZIEV E.Rupture energy evaluation for brittle materials[J].International Journal of Solids&Structures,2001,38(42):7681-7690.DOI:10.1016/S0020-7683(01)00037-3.
[8]QUR T,ZHANG Z J,ZHANG P,et al.Generalized energy failure criterion[J].Scientific Reports,2016.DOI:10.1038/srep23359.
[9]华安增,孔园波,李世平,等.岩块降压破碎的能量分析[J].煤炭学报,1995(4):389-392.HUA Anzeng,KONG Yuanbo,LI Shiping,et al.Energy analysis of depressurized rock fracture[J].China Coal Soc,1995,20(4):389-392.(in Chinese).DOI:10.13225/j.cnki.jccs.1995.04.012.
[10]HOEK E,MARTIN C D.Fracture initiation and propagation in intact rock-A review[J].Journal of Rock Mechanics and Geotechnical Engineering,2014,6(4):287-300.DOI:10.1016/j.jrmge.2014.06.001.
[11]CARPINTERI A,CHIAIA B,NEMATI K M.Complex fracture energy dissipation in concrete under different loading conditions[J].Mechanics of Materials,1997,26(2):93-108.DOI:10.1016/S0167-6636(97)00022-7.
[12]尤明庆,华安增.岩石试样破坏过程的能量分析[J].岩石力学与工程学报,2002,21(6):778-781.YOU Mingqing,HUA Anzeng.Energy analysis of failure process of rock specimens[J].Chinese J of Rock Mech Eng,2002,21(6):778-781.
[13]HORII H,NEMAT-NASSER S.Compression-induced microcrack growth in brittle solids:Axial splitting and shear failure[J].Journal of Geophysical Research Solid Earth,1985,90(B4):3105-3125.DOI:10.1029/JB090i B04p03105.
[14]LOCKNER D A,BYERLEE J D,KUKSENKO V,et al.Quasistatic fault growth and shear fracture energy in granite[J].Nature,1991,350(6313):39-42.DOI:10.1038/350039a0.
[15]MOORE D E,LOCKNER D A.The role of microcracking in shearfracture propagation in granite[J].Journal of Structural Geology,1995,17(1):95-111.DOI:10.1016/0191-8141(94)E0018-T.
[16]黄达,黄润秋,张永兴.粗晶大理岩单轴压缩力学特性的静态加载速率效应及能量机制试验研究[J].岩石力学与工程学报,2012,2:245-255.HUANG Da,HUANG Runqiu,ZHANG Yongxing.Experimental investigation on statistic loading rate effects on mechanical properties and energy mechanism of coarse crystal grain marble under uniaxial compression[J].Chinese J of Rock Mech Eng,2012,2:245-255.
[17]张志镇,高峰.单轴压缩下岩石能量演化的非线性特性研究[J].岩石力学与工程学报,2012,31(6):1198-1207.ZHANG Zhizhen,GAO Feng.Research on nonlinear characteristics of rock energy evolution under uniaxial compression[J].Chin J of Rock Mech Eng,2012,31(6):1198-1207.
[18]WANG J A,PARK H D.Comprehensive prediction of rockburst based on analysis of strain energy in rocks[J].Tunnelling&Underground Space Technology Incorporating Trenchless Technology Research,2001,16(1):49-57.DOI:10.1016/S0886-7798(01)00030-X.
[19]尤明庆,华安增.岩石试样单轴压缩的破坏形式与承载能力的降低[J].岩石力学与工程学报,1998,3:292-296.YOU Mingqing,HUA Anzeng.Damage forms and bearing capacity of rock specimen uniaxial compression[J].Chin J of Rock Mech Eng,1998,3:292-296.
[20]CAI M.Practical estimates of tensile strength and hoek-brown strength parameter m,i of brittle rocks[J].Rock Mechanics&Rock Engineering,2010,43(2):167-184.DOI:10.1007/s00603-009-0053-1.
[21]ZHAO X G,CAI M,WANG J,et al.Objective determination of crack initiation stress of brittle rocks under compression using ae measurement[J].Rock Mechanics&Rock Engineering,2015,48(6):2473-2484.DOI:10.1007/s00603-014-0703-9.
[2]BA ZˇANTZ P.Analysis of work-of-fracture method for measuring fracture energy of concrete[J].Journal of Engineering Mechanics,1996,122(2):138-144.DOI:10.1061/(ASCE)0733-9399(1996)122:2(138).
[3]HAMIEL Y,LYAKHOVSKY V,BEN-ZION Y.The elastic strain energy of damaged solids with applications to non-Linear deformation of crystalline rocks[J].Pure and Applied Geophysics,2011,168(12):2199-2210.
[4]CATES M E,WITTMER J P,BOUCHAUD J P,et al.Jamming force chains and fragile matter[J].Phys Rev Lett,1998,81(9):1841-1844.
[5]DAVIES T R H,MCSAVENEY M J,BOULTON C J.Elastic strain energy release from fragmenting grains:Effects on fault rupture[J].Journal of Structural Geology,2012,38(5):265-277.DOI:10.1016/j.jsg.2011.11.004.
[6]HAZZARD J F,YOUNG R P,MAXWELL S C.Micromechanical modeling of cracking and failure in brittle rocks[J].Journal of Geophysical Research Solid Earth,2000,105(B7):16683-16697.DOI:10.1029/2000JB900085.
[7]GAZIEV E.Rupture energy evaluation for brittle materials[J].International Journal of Solids&Structures,2001,38(42):7681-7690.DOI:10.1016/S0020-7683(01)00037-3.
[8]QUR T,ZHANG Z J,ZHANG P,et al.Generalized energy failure criterion[J].Scientific Reports,2016.DOI:10.1038/srep23359.
[9]华安增,孔园波,李世平,等.岩块降压破碎的能量分析[J].煤炭学报,1995(4):389-392.HUA Anzeng,KONG Yuanbo,LI Shiping,et al.Energy analysis of depressurized rock fracture[J].China Coal Soc,1995,20(4):389-392.(in Chinese).DOI:10.13225/j.cnki.jccs.1995.04.012.
[10]HOEK E,MARTIN C D.Fracture initiation and propagation in intact rock-A review[J].Journal of Rock Mechanics and Geotechnical Engineering,2014,6(4):287-300.DOI:10.1016/j.jrmge.2014.06.001.
[11]CARPINTERI A,CHIAIA B,NEMATI K M.Complex fracture energy dissipation in concrete under different loading conditions[J].Mechanics of Materials,1997,26(2):93-108.DOI:10.1016/S0167-6636(97)00022-7.
[12]尤明庆,华安增.岩石试样破坏过程的能量分析[J].岩石力学与工程学报,2002,21(6):778-781.YOU Mingqing,HUA Anzeng.Energy analysis of failure process of rock specimens[J].Chinese J of Rock Mech Eng,2002,21(6):778-781.
[13]HORII H,NEMAT-NASSER S.Compression-induced microcrack growth in brittle solids:Axial splitting and shear failure[J].Journal of Geophysical Research Solid Earth,1985,90(B4):3105-3125.DOI:10.1029/JB090i B04p03105.
[14]LOCKNER D A,BYERLEE J D,KUKSENKO V,et al.Quasistatic fault growth and shear fracture energy in granite[J].Nature,1991,350(6313):39-42.DOI:10.1038/350039a0.
[15]MOORE D E,LOCKNER D A.The role of microcracking in shearfracture propagation in granite[J].Journal of Structural Geology,1995,17(1):95-111.DOI:10.1016/0191-8141(94)E0018-T.
[16]黄达,黄润秋,张永兴.粗晶大理岩单轴压缩力学特性的静态加载速率效应及能量机制试验研究[J].岩石力学与工程学报,2012,2:245-255.HUANG Da,HUANG Runqiu,ZHANG Yongxing.Experimental investigation on statistic loading rate effects on mechanical properties and energy mechanism of coarse crystal grain marble under uniaxial compression[J].Chinese J of Rock Mech Eng,2012,2:245-255.
[17]张志镇,高峰.单轴压缩下岩石能量演化的非线性特性研究[J].岩石力学与工程学报,2012,31(6):1198-1207.ZHANG Zhizhen,GAO Feng.Research on nonlinear characteristics of rock energy evolution under uniaxial compression[J].Chin J of Rock Mech Eng,2012,31(6):1198-1207.
[18]WANG J A,PARK H D.Comprehensive prediction of rockburst based on analysis of strain energy in rocks[J].Tunnelling&Underground Space Technology Incorporating Trenchless Technology Research,2001,16(1):49-57.DOI:10.1016/S0886-7798(01)00030-X.
[19]尤明庆,华安增.岩石试样单轴压缩的破坏形式与承载能力的降低[J].岩石力学与工程学报,1998,3:292-296.YOU Mingqing,HUA Anzeng.Damage forms and bearing capacity of rock specimen uniaxial compression[J].Chin J of Rock Mech Eng,1998,3:292-296.
[20]CAI M.Practical estimates of tensile strength and hoek-brown strength parameter m,i of brittle rocks[J].Rock Mechanics&Rock Engineering,2010,43(2):167-184.DOI:10.1007/s00603-009-0053-1.
[21]ZHAO X G,CAI M,WANG J,et al.Objective determination of crack initiation stress of brittle rocks under compression using ae measurement[J].Rock Mechanics&Rock Engineering,2015,48(6):2473-2484.DOI:10.1007/s00603-014-0703-9.