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| EXPERIMENTAL STUDY OF PERMEABILITY AND ACOUSTIC EMISSION CHARACTERISTICS OF SANDSTONE DURING PROCESSES OF UNLOADING CONFINING PRESSURE AND DEFORMATION |
| YU Jin1，LI Hong2，CHEN Xu1，3，CAI Yanyan1，3，MU Kang1，ZHANG Yazhou1，WU Na2 |
| (1. Institute of Geotechnical Engineering，Huaqiao University，Xiamen，Fujian 361021，China；2. School of Civil and Hydraulic Engineering，Dalian University of Technology，Dalian，Liaoning 116024，China；3. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China) |
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Abstract Triaxial compression tests and acoustic emission(AE) monitoring were carried out for Jiangxi red sandstone using servo-controlled rock mechanical test system；its permeability was tested with gas at the same time. The rock permeability rules and AE characteristics under the failure processes of three types of stress paths，i.e. conventional triaxial compression，unloading confining pressure at the pre-peak and post-peak strength，were studied. The experimental results indicate that：(1) The peak strength of rock samples increases gradually with the increase of effective confining pressure，which means that the peak strength is sensitive to effective confining pressure. (2) In conventional triaxial compression test，the permeability curves fall slightly before yield and then increase dramatically after yield and suffer a slight pullback at the post-peak strain softening stage. The permeability trends before unloading of confining pressure at the pre-peak and post-peak strength are basically the same as that under conventional triaxial compression process. The curves both grow more rapidly after unloading. (3) Under the same loading path，changes of confining pressure only affect the relative values of permeability during all stages，but not affect the trends of the curves. (4) In conventional triaxial compression test，AE activity is relatively quiet prior to yield，and begins to liven up after yield then tends to be quiet again at the post-peak strain softening stage. Shortly after unloading of confining pressure at the pre-peak strength，AE activity appears extremely active and dense. The strength of signal is relative higher and reaches an obvious peak value. The AE law in the test process of unloading confining pressure at the post-peak strength is similar to that in the process of conventional triaxial compression test. (5) With the increase of confining pressure，rock appears more ductility and less brittleness in failure process. At the same confining pressure，rock presents most brittleness and reaches highest broken degree. (6) The dilatancy points of rock samples are close to the minimums of permeability. There is a well corresponding between volumetric strain and permeability with axial strain. The intensive stages of AE activity emerge after dilatancy. It is shown that there are some links among permeability，AE，stress and (volumetric) strain.
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Received: 22 March 2013
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| [1] 何满潮，钱七虎. 深部岩体力学基础[M]. 北京：科学出版社，2010： 121–126.(HE Manchao，QIAN Qihu. The basis of deep rock mechanics[M]. Beijing：Science Press，2010：121–126.(in Chinese))
[2] 井兰如，冯夏庭. 放射形废料地质处置中主要岩石力学问题[J]. 岩石力学与工程学报，2006，25(4)：833–841.(JING Lanru，FENG Xiating. Main rock mechanics issues in geological disposal of radioactive wastes[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(4)：833–841.(in Chinese))
[3] 赵阳升，王瑞凤，胡耀青，等. 高温岩体地热开发的块裂介质固流耦合三维数值模拟[J]. 岩石力学与工程学报，2002，21(12)：1 751– 1 755.(ZHAO Yangsheng，WANG Ruifeng，HU Yaoqing，et al. 3D numerical simulation for coupled THM of rock matrix-fractured media in heat extraction in HDR[J]. Chinese Journal of Rock Mechanics and Engineering，2002，21(12)：1 751–1 755.(in Chinese))
[4] 黄润秋，黄 达. 卸荷条件下花岗岩力学特性试验研究[J]. 岩石力学与工程学报，2008，27(11)：2 205–2 213.(HUANG Runqiu，HUANG Da. Experimental research on mechanical properties of granites under unloading condition[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(11)：2 205–2 213.(in Chinese))
[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 Runqiu，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)：21–33.(in Chinese))
[6] 张黎明，王在泉，石 磊. 硬质岩石卸荷破坏特性试验研究[J]. 岩石力学与工程学报，2011，30(10)：2 012–2 018.(ZHANG Liming，WANG Zaiquan，SHI Lei. Experimental study of hard rock failure characteristic under unloading condition[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(10)：2 012–2 018.(in Chinese))
[7] 汪 斌，朱杰兵，邬爱清，等. 锦屏大理岩加、卸载应力路径下力学性质试验研究[J]. 岩石力学与工程学报，2008，27(10)：2 138– 2 145.(WANG Bin，ZHU Jiebing，WU Aiqing，et al. Experimental study on mechanical properties of Jinping marble under loading and unloading stress paths[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(10)：2 138–2 145.(in Chinese))
[8] 尹光志，蒋长宝，王维忠，等. 不同卸围压速度对含瓦斯煤岩力学和瓦斯渗流特性影响试验研究[J]. 岩石力学与工程学报，2011，30(1)：68–77.(YIN Guangzhi，JIANG Changbao，WANG Weizhong，et al. Experimental study of influence of confining pressure unloading speed on mechanical properties and gas permeability of containing-gas coal rock[J]. Chinese Journal of Rock Mechanics and Engineering， 2011，30(1)：68–77.(in Chinese))
[9] 蒋长宝，尹光志，黄启翔，等. 含瓦斯煤岩卸围压变形特征及瓦斯渗流试验[J]. 煤炭学报，2011，36(5)：802–807.(JIANG Changbao，YIN Guangzhi，HUANG Qixiang，et al. Experiment of deformation property and gas permeation of containing-gas coal under confining pressure unloading process[J]. Journal of China Coal Society，2011，36(5)：802–807.(in Chinese))
[10] 尹光志，李铭辉，李文璞，等. 瓦斯压力对卸荷原煤力学及渗透特性的影响[J]. 煤炭学报，2012，37(9)：1 499–1 504.(YIN Guangzhi，LI Minghui，LI Wenpu，et al. Influence of gas pressure on mechanical and seepage characteristics of coal under unloading condition[J]. Journal of China Coal Society，2012，37(9)：1 499–1 504.(in Chinese))
[11] 梁宁慧，刘新荣，艾万民，等. 裂隙岩体卸荷渗透规律试验研究[J]. 土木工程学报，2011，44(1)：88–92.(LIANG Ninghui，LIU Xinrong，AI Wanmin，et al. Experiment study on the permeability of fractured rock under unloading[J]. China Civil Engineering Journal，2011，44(1)：88–92.(in Chinese))
[12] 苗金丽，何满潮，李德建，等. 花岗岩应变岩爆声发射特征及微观断裂机制[J]. 岩石力学与工程学报，2009，28(8)：1 593–1 603. (MIAO Jinli，HE Manchao，LI Dejian，et al. Acoustic emission characteristics of granite under strain rockburst test and its micro-fracture mechanism[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(8)：1 593–1 603.(in Chinese))
[13] 张黎明，王在泉，石 磊，等. 不同应力路径下大理岩破坏过程的声发射特性[J]. 岩石力学与工程学报，2012，31(6)：1 230–1 236. (ZHANG Liming，WANG Zaiquan，SHI Lei，et al. Acoustic emission characteristics of marble during failure process under different stress paths[J]. Chinese Journal of Rock Mechanics and Engineering， 2012，31(6)：1 230–1 236.(in Chinese))
[14] 徐速超，冯夏庭，陈炳瑞. 矽卡岩单轴循环加卸载试验及声发射特性研究[J]. 岩土力学，2009，30(10)：2 929–2 934.(XU Suchao，FENG Xiating，CHEN Bingrui. Experimental study of skarn under uniaxial cyclic loading and unloading test and acoustic emission characteristics[J]. Rock and Soil Mechanics，2009，30(10)：2 929– 2 934.(in Chinese))
[15] DAVY C A，SKOCZYLAS F，BARNICHON J D，et al. Permeability of macro-cracked argillite under confinement：gas and water testing[J]. Physics and Chemistry of the Earth：Parts A/B/C，2007，32(8/14)：667–680.
[16] BIOT M A. General theory of three-dimensional consolidation[J]. Journal of Applied Physics，1941，12(2)：155–164.
[17] 许 江，杨红伟，彭守建，等. 孔隙水压力–围压作用下砂岩力学特性的试验研究[J]. 岩石力学与工程学报，2010，29(8)：1 618–1 623.(XU Jiang，YANG Hongwei，PENG Shoujian，et al. Experimental study of mechanical property of sandstone under pore water pressure and confining pressure[J]. Chinese Journal of Rock Mechanics and Engineering，2010，29(8)：1 618–1 623.(in Chinese))
[18] LI S P，WU D X，XIE W H，et al. Effect of confining pressure，pore pressure and specimen dimension on permeability of Yinzhuang sandstone[J]. International Journal of Rock Mechanics and Mining Sciences，1997，34(3/4)：175.
[19] 李世平，李玉寿，吴振业. 岩石全应力–应变过程对应的渗透率–应变方程[J]. 岩土工程学报，1995，17(2)：13–19.(LI Shiping，LI Yushou，WU Zhenye. The permeability-strain equations relating to complete stress-strain path of the rock[J]. Chinese Journal of Geotechnical Engineering，1995，17(2)：13–19.(in Chinese))
[20] 彭苏萍，孟召平，王 虎，等. 不同围压下砂岩孔渗规律试验研究[J]. 岩石力学与工程学报，2003，22(5)：742–746.(PENG Suping，MENG Zhaoping，WANG Hu，et al. Testing study on pore ratio and permeability of sandstone under different confining pressures[J]. Chinese Journal of Rock Mechanics and Engineering，2003，22(5)：742–746.(in Chinese))
[21] 陈卫忠，吕森鹏，郭小红，等. 脆性岩石卸围压试验与岩爆机制研究[J]. 岩土工程学报，2010，32(6)：963–969.(CHEN Weizhong，LU Senpeng，GUO Xiaohong，et al. Unloading confining pressure for brittle rock and mechanism of rock burst[J]. Chinese Journal of Geotechnical Engineering，2010，32(6)：963–969.(in Chinese))
[22] SCHULZE O，POPP T，KERN H. Development of damage and permeability in deforming rock salt[J]. Engineering Geology，2001，61(2)：163–180.
[23] 周建军，周 辉，邵建富. 脆性岩石各向异性损伤和渗流耦合细观模型[J]. 岩石力学与工程学报，2007，26(2)：368–373.(ZHOU Jianjun，ZHOU Hui，SHAO Jianfu. Coupled micromechanical model for anisotropic damage and permeability variation in brittle rocks[J]. Chinese Journal of Rock Mechanics and Engineering，2007，26(2)：368–373.(in Chinese)) |
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2014, Vol. 33 
