大理岩加、卸荷破坏过程的三维颗粒流模拟
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摘要
从大理岩常规三轴加、卸荷室内试验出发,结合PFC3D颗粒流程序进行分析,在明确室内试验与数值模拟试验卸荷速率对应关系的基础上,对不同卸荷速率下试样破坏过程的力学特性及破坏机制进行探讨。结果表明:加、卸荷路径下整个加载过程中张拉裂纹数量均明显高于剪切裂纹;常规三轴试验损伤应力之后,裂纹围绕某一速率进行扩展,卸荷试验损伤应力之后,裂纹的发展是突发性的;不同应力路径下试样损伤破坏的差异性主要形成于损伤应力至峰值应力这一阶段,直至卸荷速率超过6 MPa/s,试样的损伤程度与破坏形式逐渐趋于一致;随着围压的增大,不同卸荷速率下岩石破坏均呈现出由张拉破坏逐渐向剪切破坏过渡。
Combing with the PFC3 D software, the conventional triaxial loading and unloading tests were carried out on marble specimens in the laboratory. Then the results of unloading rate were compared between the numerical simulation and lab test.According to the crack propagation in mesoscale, the mechanical properties and failure mechanism of specimens under different unloading rates were discussed. The results show that the number of tensile cracks on specimens was obviously higher than that of shear cracks at the loading stage in the loading and unloading process. The crack propagated at a certain rate after the conventional triaxial test damage stress, while the crack developed suddenly after the unloading test damage stress. Under different stress paths, the difference of damage failure between the damage stress and the peak stress was mainly formed in the stage from damage stress to peak stress. The damage degree and failure form of the specimen tended to be consistent until the unloading rate beyond 6 MPa/s.With the increase of the confining pressure, rock failure showed a transition from tensile failure to shear failure at different unloading rates.
Combing with the PFC3 D software, the conventional triaxial loading and unloading tests were carried out on marble specimens in the laboratory. Then the results of unloading rate were compared between the numerical simulation and lab test.According to the crack propagation in mesoscale, the mechanical properties and failure mechanism of specimens under different unloading rates were discussed. The results show that the number of tensile cracks on specimens was obviously higher than that of shear cracks at the loading stage in the loading and unloading process. The crack propagated at a certain rate after the conventional triaxial test damage stress, while the crack developed suddenly after the unloading test damage stress. Under different stress paths, the difference of damage failure between the damage stress and the peak stress was mainly formed in the stage from damage stress to peak stress. The damage degree and failure form of the specimen tended to be consistent until the unloading rate beyond 6 MPa/s.With the increase of the confining pressure, rock failure showed a transition from tensile failure to shear failure at different unloading rates.
引文
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[18]吴顺川,周喻,高斌,等.卸荷岩爆试验及PFC 3D数值模拟研究[J].岩石力学与工程学报,2010,29(増刊2):4082-4088.WU Shun-chuan,ZHOU Yu,GAO Bin,et al.Study of unloading tests of rock burst and PFC 3D numerical simulation[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(Suppl.2):4082-4088.
[2]张凯,周辉,潘鹏志,等.不同卸荷速率下岩石强度特性研究[J].岩土力学,2010,31(7):2072-2078.ZHANG Kai,ZHOU Hui,PAN Peng-zhi,et al.Characteristics of strength of rocks under different unloading rates[J].Rock and Soil Mechanics,2010,31(7):2072-2078.
[3]邱士利,冯夏庭,张传庆,等.不同卸围压速率下深埋大理岩卸荷力学特性试验研究[J].岩石力学与工程学报,2010,29(9):1807-1817.QIU Shi-li,FENG Xia-ting,ZHANG Chuan-qing,et al.Experimental research on mechanical properties of deep-buried marble under different unloading rates of confining pressures[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(9):1807-1817.
[4]李建林,王瑞,蒋昱州,等.砂岩三轴卸荷力学特性试验研究[J].岩石力学与工程学报,2010,29(10):2034-2041.LI Jian-lin,WANG Rui,JIANG Yu-zhou,et al.Experimental study of sandstone mechanical properties by unloading triaxial tests[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):2034-2041.
[5]黄润秋,黄达.高地应力条件下卸荷速率对锦屏大理岩力学特性影响规律试验研究[J].岩石力学与工程学报,2010,29(1):21-33.HUANG Run-qiu,HUANG Da.Experimental research on affection laws of unloading rates on mechanical properties of Jinping marble under high geostress[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(1):21-23.
[6]尤明庆,华安增.岩石试样的三轴卸围压试验[J].岩石力学与工程学报,1998,17(1):24-29.YOU Ming-qing,HUA An-zeng.Triaxial confining depressure test of rock sample[J].Chinese Journal of Rock Mechanics and Engineering,1998,17(1):24-29.
[7]霍亮,周雁,杨春和,等.不同沉积年代泥岩卸荷力学特性试验研究[J].岩土力学,2017,38(3):714-722.HUO Liang,ZHOUZ Yan,YANG Chun-he,et al.Experimental study of unloading mechanical behaviour of mudstone in different geological era[J].Rock and Soil Mechanics,2017,38(3):714-722.
[8]朱焕春.PFC及其在矿山崩落开采研究中的应用[J].岩石力学与工程学报,2006,25(9):1927-1931.ZHU Huan-chun.PFC and application case of caving study[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(9):1927-1931.
[9]CUNDALL P A,STRACK O D L.Particle flow code in2D[M].Minnesota:Itasca Consulting Group,Inc.,1999.
[10]POTYONDY D O,CUNDALL P A.A bonded-particle model for rock[J].International Journal of Rock Mechanics and Mining Sciences,2004,41(8):1329-1364.
[11]POTYONDY D O.Simulating stress corrosion with a bonded-particle model for rock[J].International Journal of Rock Mechanics and Mining Sciences,2007,44(5):667-691.
[12]杜鹃.二维颗粒流程序PFC 2D特点及其应用现状综述[J].安徽建筑工业学院学报,2009,17(5):68-70.DU Juan.The overview of characteristics and applications of PFC 2D[J].Journal of Anhui Institute of Architecture&Industry,2009,17(5):68-70.
[13]徐金明,谢芝蕾,贾海涛.石灰岩细观力学特性的颗粒流模拟[J].岩土力学,2010,31(增刊2):390-395.XU Jin-ming,XIE Zhi-lei,JIA Hai-tao.Simulation of mesomechanical properties of limestone using particle flow code[J].Rock and Soil Mechanics,2010,31(Suppl.2):390-395.
[14]苗胜军,杨志军,龙超,等.混合花岗岩加载细观力学特性及破裂演化规律[J].江苏大学学报(自然科学版),2012,33(4):469-473.MIAO Sheng-ju,YANG Zhi-jun,LONG Chao,et al.Micro-mechanical characteristics and cracks revolution laws of migmatitic granite under different loading conditions[J].Journal of Jiangsu University(Natural Science),2012,33(4):469-473.
[15]梁正召,唐春安,李厚祥,等.单轴压缩下横观各向同性岩石破裂过程的数值模拟[J].岩土力学,2005,26(1):57-62.LIANG Zheng-zhao,TANG Chun’an,LI Hou-xiang,et al.A numerical study on failure process of transversely isotropic rock subjected to uni-axial compression[J].Rock and Soil Mechanics,2005,26(1):57-62.
[16]肖洪天,周维垣.脆性岩石变形与破坏的细观力学模型研究[J].岩石力学与工程学报,2001,20(2):151-155.XIAO Hong-tian,ZHOU Wei-yuan.A microscopic model of deformation and failure for brittle rocks[J].Chinese Journal of Rock Mechanics and Engineering,2001,
[17]马春驰,李天斌,陈国庆,等.硬脆岩石的微观颗粒模型及其卸荷岩爆效应研究[J].岩石力学与工程学报,2015,34(2):217-227.MA Chun-chi,LI Tian-bin,CHEN Guo-qing,et al.Amicro particle model for hard brittle rock and the effect of the unloading rock burst[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(2):217-227.
[18]吴顺川,周喻,高斌,等.卸荷岩爆试验及PFC 3D数值模拟研究[J].岩石力学与工程学报,2010,29(増刊2):4082-4088.WU Shun-chuan,ZHOU Yu,GAO Bin,et al.Study of unloading tests of rock burst and PFC 3D numerical simulation[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(Suppl.2):4082-4088.