层状大理岩破裂过程力学特性与能量演化各向异性研究
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摘要
为了揭示互层状大理岩压缩过程中能量演化和破裂形态的各向异性,采用GCTS 2000岩石力学试验机,应用全应力应变分析、能量分析和CT扫描相结合的方法,对不同互层角度的大理岩试样开展了相关试验研究。结果表明:岩石的物理力学性状具有明显的各向异性,抗压强度随互层倾角变化呈U型分布,弹性模量随倾角增大逐渐减小;能量演化揭示出明显的储能与释能各向异性特征,30°倾角试样破坏所需能量最小,90°倾角试样破坏所需能量最大;提出了基于能量原理的特征起裂和扩展应力的确定方法,并证明了该方法的可靠性;岩样的宏观破裂形态表现为互层间的劈裂张拉破坏、弱面的剪切滑移破坏和贯穿基质与软夹层的张剪破坏,相应的细观CT图像表现为多条平直裂缝、单一贯穿裂缝和多条弯折裂缝。试验结果充分揭示了层状岩石破裂特征与储能释能特性的相关性,岩石的能量演化机制与其宏细观破裂形态受控于岩石的内部互层状结构,研究结果可为岩爆灾害的防控和深部资源安全开采提供必要的理论依据。
In order to reveal the anisotropy of energy evolution and fracturing characteristics of interbedded marble during uniaxial compression, multiple marble specimens with different interbedded angles were tested using GCTS 2000 rock mechanics test machine. Meanwhile, methods of full stress-strain analysis, energy analysis and CT scanning were adopted. Results show that: there are strong anisotropic characteristics in the physical and mechanical properties of tested rocks. The uniaxial compressive strength varies with interbedded angle and follows a U-shaped distribution. While the elastic modulus decreases with the increase in interbedded angle. Energy evolution reflects obvious anisotropy of energy storage and release. When the inclination angle is 30°, the energy required for rock failure is the smallest. In contrast, that energy is the largest for 90° inclination angle. A method for determining the characteristic initiation stress and expansion stress based on energy principle is proposed, and its reliability is verified. Rock's macroscopic fracture morphology mainly manifests as the splitting tensile failure between interbed, the shear slip failure of weak planes and the transtension failure through base material and soft interlayer. Rock's microscopic CT images show multiple straight fractures, single penetrating fracture and multiple bent fractures, respectively. Above experimental results fully reveal the correlation between marble's fracture characteristics and its energy evolution. The rock's energy evolution mechanism and its macro-micro fracture morphology are controlled by internal interbedded structure. Outcomes of this study could provide useful theoretical basis for the prevention and control of rock burst disasters and for the safe exploitation of deep resources.
In order to reveal the anisotropy of energy evolution and fracturing characteristics of interbedded marble during uniaxial compression, multiple marble specimens with different interbedded angles were tested using GCTS 2000 rock mechanics test machine. Meanwhile, methods of full stress-strain analysis, energy analysis and CT scanning were adopted. Results show that: there are strong anisotropic characteristics in the physical and mechanical properties of tested rocks. The uniaxial compressive strength varies with interbedded angle and follows a U-shaped distribution. While the elastic modulus decreases with the increase in interbedded angle. Energy evolution reflects obvious anisotropy of energy storage and release. When the inclination angle is 30°, the energy required for rock failure is the smallest. In contrast, that energy is the largest for 90° inclination angle. A method for determining the characteristic initiation stress and expansion stress based on energy principle is proposed, and its reliability is verified. Rock's macroscopic fracture morphology mainly manifests as the splitting tensile failure between interbed, the shear slip failure of weak planes and the transtension failure through base material and soft interlayer. Rock's microscopic CT images show multiple straight fractures, single penetrating fracture and multiple bent fractures, respectively. Above experimental results fully reveal the correlation between marble's fracture characteristics and its energy evolution. The rock's energy evolution mechanism and its macro-micro fracture morphology are controlled by internal interbedded structure. Outcomes of this study could provide useful theoretical basis for the prevention and control of rock burst disasters and for the safe exploitation of deep resources.
引文
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[18]王宇,李晓,武艳芳,等.脆性岩石起裂应力水平与脆性指标关系探讨[J].岩石力学与工程学报,2014,33(2):264-275.WANG Yu,LI Xiao,WU Yanfang,et al.Research on relationship between crack initiation stress level and brittleness indices for brittle rocks[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(2):264-275.
[2]何满潮,苗金丽,李德建,等.深部花岗岩试样岩爆过程实验研究[J].岩石力学与工程学报,2007,26(5):865-876.HE Manchao,MIAO Jinli,LI Dejian,et al.Experimental study on rockburst processes of granite specimen at great depth[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(5):865-876.
[3]杨振琦,邓文学,张鹏海,等.层理倾角对黑云变粒岩声发射特征的影响[J].采矿与安全工程学报,2016,33(3):521-527.YANG Zhenqi,DENG Wenxue,ZHANG Penghai,et al.The influence of bedding angle on acoustic emission characteristics in biotite granulite[J].Journal of Mining&Safety Engineering,2016,33(3):521-527.
[4]赵文瑞.泥质粉砂岩各向异性强度特征[J].岩土工程学报,1984,6(1):32-37.ZHAO Wenrui.Strength properties of anisotropic rock of an argillaceous siltstone[J].Chinese Journal of Geotechnical Engineering,1984,6(1):32-37.
[5]GHOLAMI R,RASOULI V.Mechanical and elastic properties of transversely isotropic slate[J].Rock Mechanics and Rock Engineering,2014,47(5):1763-1773.
[6]ASADI M,BAGHERIPOUR M H.Modified criteria for sliding and non-sliding failure of anisotropic jointed rocks[J].International Journal of Rock Mechanics and Mining Sciences,2015,73:95-101.
[7]SINGH J,RAMAMURTHY T,RAO G V.Strength anisotropies in rocks[J].Indian Geotechnical Journal,1989,19(2):147-166.
[8]谢和平,鞠杨,黎立云.基于能量耗散与释放原理的岩石强度与整体破坏准则[J].岩石力学与工程学报,2005,24(17):3003-3010.XIE Heping,JU Yang,LI Liyun.Criteria for strength and structural failure of rocks based on energy dissipation and energy release principles[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(17):3003-3010.
[9]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 rock masses[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(9):1729-1740.
[10]邱士利,冯夏庭,张传庆,等.均质各向同性硬岩统一应变能强度准则的建立及验证[J].岩石力学与工程学报,2013,32(4):714-727.QIU Shili,FENG Xiating,ZHANG Chuanqing,et al.Establishment of unified strain energy strength criterion of homogeneous and isotropic hard rocks and its validation[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(4):714-727.
[11]张黎明,高速,任明远,等.岩石加荷破坏弹性能和耗散能演化特性[J].煤炭学报,2014,39(7):1238-1242.ZHANG Liming,GAO Su,REN Mingyuan,et al.Rock elastic strain energy and dissipation strain energy evolution characteristics under conventional triaxial compression[J].Journal of China Coal Society,2014,39(7):1238-1242.
[12]VAKILI A,ALBRECHT J,SANDY M.Rock strength anisotropy and its importance in underground geotechnical design[C]//Proceedings of the Third Australasian Ground Control in Mining Conference.Melbourne:The Australasian Institute of Mining and Metallurgy,2014:167-180.
[13]陈子全,何川,吴迪,等.深埋碳质千枚岩力学特性及其能量损伤演化机制[J].岩土力学,2018,39(2):445-456.CHEN Ziquan,HE Chuan,WU Di,et al.Mechanical properties and energy damage evolution mechanism of deep-buried carbonaceous phyllite[J].Rock and Soil Mechanics,2018,39(2):445-456.
[14]尤明庆,苏承东,徐涛.岩石试样的加载卸载过程及杨氏模量[J].岩土工程学报,2001,23(5):588-592.YOU Mingqing,SU Chengdong,XU Tao.Loading or unloading process in axial direction and Young's modulus of rock specimen[J].Chinese Journal of Geotechnical Engineering,2001,23(5):588-592.
[15]LIANG C,WU S,LI X,et al.Effects of strain rate on fracture characteristics and mesoscopic failure mechanisms of granite[J].International Journal of Rock Mechanics and Mining Sciences,2015,76:146-154.
[16]MARTIN C D.The strength of massive Lac du Bonnet granite around underground opening[D].Manitoba,Canada:University of Manitoba,1993.
[17]朱泽奇,盛谦,冷先伦,等.三峡花岗岩起裂机制研究[J].岩石力学与工程学报,2007,26(12):2570-2575.ZHU Zeqi,SHENG Qian,LENG Xianlun,et al.Study on crack initiation mechanism of three gorges granite[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(12):2570-2575.
[18]王宇,李晓,武艳芳,等.脆性岩石起裂应力水平与脆性指标关系探讨[J].岩石力学与工程学报,2014,33(2):264-275.WANG Yu,LI Xiao,WU Yanfang,et al.Research on relationship between crack initiation stress level and brittleness indices for brittle rocks[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(2):264-275.