细砂岩裂纹周围变形破坏过程及应变场分布
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摘要
用扫描电镜实时观测研究了含不同方向预制裂纹的平板状砂岩试件中不同尺度上微破裂的萌生、扩展、集结和连通,以及形成宏观破裂的过程,对一些局部破裂现象进行了实时显微照相。在实验观测的基础上,利用数字图象相关程序对裂纹周围变形场进行了分析计算。研究结果表明:在裂纹开裂过程中,裂纹周围产生较强的应变集中带,其应变值远远超过单轴压缩试验中记录到的平均2％～5％的破坏应变值;而远离破裂带,应变量则低于2％～5％的破坏应变值,说明了岩石试件的破坏过程是一个非均匀的变形分布及传播过程。
Uniaxial compression tests on sandstone samples containing a prefabricated fracture were made. Photomicrographs showing the typical characteristics of the sub-crack development were taken under direct scanning electron microscope (SEM) observation during the test From these photomicrographs, the direct physical patterns showing the initiation, growth and coalescence of sub-cracks and micro-cracks in sandstone specimen are obtained. Based on the test results, the strain field around the sub-cracks was calculated using the digital image correlation method. The results show that strain concentration which is much higher than the average failure strain around 2-5% for sandstone, occurred close to the crack area. But in far away area, the strain is much lower than 2-5%. Therefore, the crack development in sandstone specimen is a nonhomogeneous deforming process.
Uniaxial compression tests on sandstone samples containing a prefabricated fracture were made. Photomicrographs showing the typical characteristics of the sub-crack development were taken under direct scanning electron microscope (SEM) observation during the test From these photomicrographs, the direct physical patterns showing the initiation, growth and coalescence of sub-cracks and micro-cracks in sandstone specimen are obtained. Based on the test results, the strain field around the sub-cracks was calculated using the digital image correlation method. The results show that strain concentration which is much higher than the average failure strain around 2-5% for sandstone, occurred close to the crack area. But in far away area, the strain is much lower than 2-5%. Therefore, the crack development in sandstone specimen is a nonhomogeneous deforming process.
引文
[1] Horii H, Nemat-Nasser S. Compression induced microcrack growth in brittle solids: axial splitting and shear failure[J]. Journal of Geophysical Research, 1985, 90(B4) : 3 105-3 125．
[2] Huang J F, Wang Z Y, Zhao Y H. The development of rock fracture from microfracturing to main fracture formation[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1993, 30: 925-928
[3] King G. The accommodation of large strains in the upper lithosphere of the earth and other solids by self-similar fault systems: The geometrical origin of b-value[J]. Pure and applied Geophysics, 1983, 121: 761-815．
[4] Liu H, Bazargan Sabet B, Chanchole S. Non-linear analysis of acoustic measurements-Characterization of the growth of microcracks in geomaterials[J]. Acustica, 1996, 82(2) :321-327．
[5] Nemat-Nasser S, Horii, H. Compression-induced non-planar crack extension with application to splitting exfoliation and rock burst[J]. Journal of Geophysical Research, 1982, 87(B8) : 6 805-6 821．
[6] 赵永红,黄杰藩,王仁.破裂带发育的SEM实验研究及其对地震前兆的启示[J].地球物理学报,1993,36(4) :453-462．
[7] 赵永红,黄杰藩,候建军等.岩石细观破裂的实验观测研究及其对了解地震活动性的启示[J].地球物理学报,1995,38(5) :627-635．
[8] Zhao Yonghong, Liang Haihua, Huang Jiefan, Geng Jinda, Wang Ren. Development of subcracks around compound fractures in rock specimen, special issue of pure and applied geophysics[J]. Mechanics Problems in Geodynamics, 1995, 145(3-4) : 759-773．
[9] Batzle M L, Simmons G, Siefried R W. Microcrack closure in rocks under stress: direct observation[J]. Journal of Geophysical Research, 1980, 85: 7 072-7090．
[10] Lindqvist P A, Lai H H, Alm O. Indentation fracture development in rock continously observed with a scanning electron microscope[J], International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1984,21: 165-182,
[11] Nolen-Hoeksema R C, Gordon R B. Optical detection of crack patterns in the opening-mode fracture of marble[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1987, 24: 135-144．
[12] Zhao Y, Huang J, Wang R. Fractal characteristics of mesofracture in compressed rock specimens[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1993, 30(7) : 877-882．
[13] Zhao Y, Huang J, Wang R. Real-time SEM observations of the microfracturing process in rock during a compression test[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1993, 30(6) : 643-652．
[14] Zhao Yonghong. Crack pattern evolution and a fractal damage constitutive model of rock material[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1998, 35(3) : 349- 366．
[15] Huang Jiefan, Chen Ganglin, Zhao Yonghong, Wang ren.An experimental study of the strain fields developmentprior to failure of a marble plate under compression[J].Tectonophysics, 1990, 175: 269-284．
[16] Chu T C, Ranson W F, Sutton M A, Peters W H.Application of digital-image correlation technique toexperimental mechanics[J], Expeimental Mechanis,1985, 25: 232-244．
[17] 赵永红,熊春阳,戴天环,方竞.细砂岩变形破坏过程的实验研究[A].力学2000年会议文集[C].北京:气象出版社,2000． 351-352．
[18] 赵水红,梁海华,熊春阳,方竞,用数字图像相关技术进行岩石损伤的变形分析[J].岩石力学与工程学报,2002,21(1) :73-76．
[19] Fujiwara S, Rosen P, Tobita M, Molakami M. Crustal deformation measurements using repeat-pass JERS 1 synthetic aperture redar interferometry near the Izu Peninsula[J]. Journal of Geophysical Research, 1998, 103(B2) :2411-2426．
[20] Massonnet D, Rossi M, Oarmona C, et al, The displacement field of the landers earthquake mapped by radar interferometry[J]. Nature, 1993, 364(8) : 138-142．
[2] Huang J F, Wang Z Y, Zhao Y H. The development of rock fracture from microfracturing to main fracture formation[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1993, 30: 925-928
[3] King G. The accommodation of large strains in the upper lithosphere of the earth and other solids by self-similar fault systems: The geometrical origin of b-value[J]. Pure and applied Geophysics, 1983, 121: 761-815．
[4] Liu H, Bazargan Sabet B, Chanchole S. Non-linear analysis of acoustic measurements-Characterization of the growth of microcracks in geomaterials[J]. Acustica, 1996, 82(2) :321-327．
[5] Nemat-Nasser S, Horii, H. Compression-induced non-planar crack extension with application to splitting exfoliation and rock burst[J]. Journal of Geophysical Research, 1982, 87(B8) : 6 805-6 821．
[6] 赵永红,黄杰藩,王仁.破裂带发育的SEM实验研究及其对地震前兆的启示[J].地球物理学报,1993,36(4) :453-462．
[7] 赵永红,黄杰藩,候建军等.岩石细观破裂的实验观测研究及其对了解地震活动性的启示[J].地球物理学报,1995,38(5) :627-635．
[8] Zhao Yonghong, Liang Haihua, Huang Jiefan, Geng Jinda, Wang Ren. Development of subcracks around compound fractures in rock specimen, special issue of pure and applied geophysics[J]. Mechanics Problems in Geodynamics, 1995, 145(3-4) : 759-773．
[9] Batzle M L, Simmons G, Siefried R W. Microcrack closure in rocks under stress: direct observation[J]. Journal of Geophysical Research, 1980, 85: 7 072-7090．
[10] Lindqvist P A, Lai H H, Alm O. Indentation fracture development in rock continously observed with a scanning electron microscope[J], International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1984,21: 165-182,
[11] Nolen-Hoeksema R C, Gordon R B. Optical detection of crack patterns in the opening-mode fracture of marble[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1987, 24: 135-144．
[12] Zhao Y, Huang J, Wang R. Fractal characteristics of mesofracture in compressed rock specimens[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1993, 30(7) : 877-882．
[13] Zhao Y, Huang J, Wang R. Real-time SEM observations of the microfracturing process in rock during a compression test[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1993, 30(6) : 643-652．
[14] Zhao Yonghong. Crack pattern evolution and a fractal damage constitutive model of rock material[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1998, 35(3) : 349- 366．
[15] Huang Jiefan, Chen Ganglin, Zhao Yonghong, Wang ren.An experimental study of the strain fields developmentprior to failure of a marble plate under compression[J].Tectonophysics, 1990, 175: 269-284．
[16] Chu T C, Ranson W F, Sutton M A, Peters W H.Application of digital-image correlation technique toexperimental mechanics[J], Expeimental Mechanis,1985, 25: 232-244．
[17] 赵永红,熊春阳,戴天环,方竞.细砂岩变形破坏过程的实验研究[A].力学2000年会议文集[C].北京:气象出版社,2000． 351-352．
[18] 赵水红,梁海华,熊春阳,方竞,用数字图像相关技术进行岩石损伤的变形分析[J].岩石力学与工程学报,2002,21(1) :73-76．
[19] Fujiwara S, Rosen P, Tobita M, Molakami M. Crustal deformation measurements using repeat-pass JERS 1 synthetic aperture redar interferometry near the Izu Peninsula[J]. Journal of Geophysical Research, 1998, 103(B2) :2411-2426．
[20] Massonnet D, Rossi M, Oarmona C, et al, The displacement field of the landers earthquake mapped by radar interferometry[J]. Nature, 1993, 364(8) : 138-142．
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