|
|
|
| Critical confining pressure condition for isotropic transformation of foliated rocks under compressive loads
|
| YIN Xiaomeng1，2，YAN Echuan2，LI Ling3，MA Chao4
|
| (1. College of Intelligent Construction，Wuchang University of Technology，Wuhan，Hubei 430223，China；2. Faculty of Engineering，
China University of Geosciences，Wuhan，Hubei 430074，China；3. Xiangyang Institute of Geological Engineering Investigation，
Xiangyang，Hubei 441003，China；4. School of Automotive and Transportation Engineering，Hubei University of Arts and
Sciences，Xiangyang，Hubei 441053，China)
|
|
|
|
|
Abstract Abstract：The anisotropy of rock gradually weakens or even disappears with increasing the confining pressure. However，the critical condition for the transformation from anisotropic to isotropy is still lack of in-depth research. Taking foliated rocks as the object，the fabric characteristics of this kind of typical anisotropic rock were summarized and the empirical criterion for shear-slip failure along the weak plane of rock was constructed. Combined with the previous failure criterion created based on the concept of critical state and Mohr-Coulomb criterion，the critical confining pressure at the point where the anisotropy of foliated rock is transformed into isotropy was predicted theoretically. Then，the prediction result was verified by statistical analysis on previous experimental data. The results are as follows. Foliated rocks contain representative phyllosilicates，which constitute directional weak layers and are distributed in a quasi interbedded manner with the hard layers composed of granular minerals. Under a certain loading direction，foliated rocks suffer shear-slip failure along the weak plane. The empirical friction coefficients of rocks in this failure mode are 0.40 and 0.25 under the conditions of medium-low and high confining pressure respectively. The transformation confining pressure is dependent on the uniaxial compressive strength and internal friction angle of foliated rocks subjected to compressive loading perpendicular to weak planes. The transformation confining pressure of foliated rocks is generally greater than 1.5 and increases with the increase of and . For the foliated rocks with a high content of phyllosilicates，the transformation confining pressure coefficient is often between 1.9 and 3.6.
|
|
|
|
|
|
| [1] ATTEWELL P B，SANDFORD M R. Intrinsic shear strength of a brittle，anisotropic rock—I：experimental and mechanical interpretation[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1974，11(11)：423–430.
[2] RAMAMURTHY T，RAO G V，SINGH J. Engineering behaviour of phyllites[J]. Engineering Geology，1993，33(3)：209–225.
[3] NASSERI M H，RAO K，RAMAMURTHY T. Transversely isotropic strength and deformational behavior of Himalayan schists[J]. International Journal of Rock Mechanics and Mining Sciences，2003，40：3–23.
[4] MCLAMORE R，GRAY K E. The mechanical behavior of anisotropic sedimentary rocks[J]. Journal of Engineering for Industry，1967，89(1)：62–73.
[5] BEHRESTAGHI M，RAO K S，RAMAMURTHY T. Engineering geological and geotechnical responses of schistose rocks from dam project areas in India[J]. Engineering Geology，1996，44(1)：183–201.
[6] FEREIDOONI D，KHANLARI G R，HEIDARI M，et al. Assessment of inherent anisotropy and confining pressure influences on mechanical behavior of anisotropic foliated rocks under triaxial compression[J]. Rock Mechanics and Rock Engineering，2016，49(6)：2 155–2 163.
[7] SINGH J，RAMAMURTHY T，RAO G V. Strength anisotropies in rocks[J]. Indian Geotechnical Journal，1989，19(2)：147–166.
[8] 衡 帅，杨春和，张保平，等. 页岩各向异性特征的试验研究[J]. 岩土力学，2015，36(3)：609–616.(HENG Shuai，YANG Chunhe，ZHANG Baoping，et al. Experimental research on anisotropic properties of shale[J]. Rock and Soil Mechanics，2015，36(3)：609–616.(in Chinese))
[9] 吴永胜，谭忠盛，余贤斌，等. 龙门山北段千枚岩强度及变形特性对比试验研究[J]. 岩土工程学报，2017，39(6)：1 106–1 114.(WU Yongsheng，TAN Zhongsheng，YU Xianbin，et al. Comparative tests on strength and deformation of phyllite of northern tunnels of Longmen Mountains[J]. Chinese Journal of Geotechnical Engineering，2017，39(6)：1 106–1 114.(in Chinese))
[10] 邓华锋，王 伟，李建林，等. 层状砂岩各向异性力学特性试验研究[J]. 岩石力学与工程学报，2018，37(1)：112–120.(DENG Huafeng，WANG Wei，LI Jianlin，et al. Experimental study on anisotropic characteristics of bedded sandstone[J]. Chinese Journal of Rock Mechanics and Engineering，2018，37(1)：112–120.(in Chinese))
[11] 单治钢，陈国庆，周春宏，等. 丹巴水电站石英云母片岩力学特性及岩体质量分类[J]. 岩石力学与工程学报，2013，32(10)：2 070– 2 078.(SHAN Zhigang，CHEN Guoqing，ZHOU Chunhong，et al. Mechanical properties and rock mass quality classification of quartz mica schist for Danba hydropower station[J]. Chinese Journal of Rock Mechanics and Engineering，2013，32(10)：2 070–2 078.(in Chinese))
[12] TIEN Y M，KUO M C，JUANG C H . An experimental investigation of the failure mechanism of simulated transversely isotropic rocks[J]. International Journal of Rock Mechanics and Mining Sciences，2006，43(8)：1 163–1 181.
[13] 郭松峰，祁生文，黄晓林. 岩体强度各向异性及其转化的应力条件[J]. 岩石力学与工程学报，2013，32(增2)：3 221–3 227.(GUO Songfeng，QI Shengwen，HUANG Xiaolin. Anisotropy of rockmass strength and its transformation critical confining stress[J]. Chinese Journal of Rock Mechanics and Engineering，2013，32(Supp.2)：3 221–3 227.(in Chinese))
[14] MARTINMCCABE W，KOERNER R M. High pressure shear strength investigation of an anisotropic mica schist rock[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1975，12(8)：219–228.
[15] SAEIDI O，RASOULI V，VANEGHI R G，et al. A modified failure criterion for transversely isotropic rocks[J]. Geoscience Frontiers，2014，5(2)：215–225.
[16] 周 阳，苏生瑞，李 鹏，等. 板裂千枚岩微观结构与力学性质[J]. 吉林大学学报：地球科学版，2019，49(2)：504–513.(ZHOU Yang，SU Shengrui，LI Peng，et al. Microstructure and mechanical properties of broken phyllite[J]. Journal of Jilin University：Earth Science Edition，2019，49(2)：504–513.(in Chinese))
[17] YIN X M，YAN E C，WANG L N，et al. Anisotropy of quartz mica schist based on quantitative extraction of fabric information[J]. Bulletin of Engineering Geology and the Environment，2020，79(5)：2 439–2 456.
[18] SAROGLOU H，TSIAMBAOS G. A modified Hoek-Brown failure criterion for anisotropic intact rock[J]. International Journal of Rock Mechanics and Mining Sciences，2008，45(2)：223–234.
[19] SHEA W T，KRONENBERG A K. Strength and anisotropy of foliated rocks with varied mica contents[J]. Journal of Structural Geology，1993，15(9–10)：1 097–1 121.
[20] RAWLING G C，BAUD P，TENGFONG W. Dilatancy，brittle strength，and anisotropy of foliated rocks：experimental deformation and micro-mechanical modeling[J]. Journal of Geophysical Research，2002，107(B10)：2 234–2 247.
[21] BYERLEE J . Friction of rocks[J]. Pure and Applied Geophysics，1978，116(4–5)：615–626.
[22] COULSON J H. The effects of surface roughness on the shear strength of joints in rock[M]. Urbana：University of Illinois at Urbana- Champaign，1970：120–125.
[23] CARPENTER B M，MARONE C，SAFFER D M . Weakness of the San Andreas Fault revealed by samples from the active fault zone[J]. Nature Geoscience，2011，4(4)：251–254.
[24] COLLETTINI C，TESEI T，SCUDERI M M，et al. Beyond Byerlee friction，weak faults and implications for slip behavior[J]. Earth and Planetary Science Letters，2019，519：245–263.
[25] COLLETTINI C，VITI C，SMITH S，et al. Development of interconnected talc networks and weakening of continental low-angle normal faults[J]. Geology，2009，37(6)：567–570.
[26] TESEI T，COLLETTINI C，CARPENTER B M，et al. Frictional strength and healing behavior of phyllosilicate‐rich faults[J]. Journal of Geophysical Research：Solid Earth，2012，117(B9)：1–13.
[27] IKARI M J，NIEMEIJER A R，MARONE C. Experimental investigation of incipient shear failure in foliated rock[J]. Journal of Structural Geology，2015，77：82–91.
[28] NIEMEIJER A R，SPIERS C J. Influence of phyllosilicates on fault strength in the brittle-ductile transition: Insights from rock analogue experiments[J]. Geological Society，London，Special Publications，2005，245(1)：303–327.
[29] NIEMEIJER A，MARONE C，ELSWORTH D. Fabric induced weakness of tectonic faults[J]. Geophysical Research Letters，2010，37(3)：L03304.
[30] SMITH S A F，FAULKNER D R. Laboratory measurements of the frictional properties of the Zuccale low‐angle normal fault，Elba Island，Italy[J]. Journal of Geophysical Research：Solid Earth，2010，115(B2)：1–17.
[31] IKARI M J，NIEMEIJER A R，MARONE C . The role of fault zone fabric and lithification state on frictional strength，constitutive behavior，and deformation microstructure[J]. Journal of Geophysical Research，2011，116：B08404.
[32] PATERSON M S，WEISS L E . Experimental deformation and folding in phyllite[J]. Geological Society of America Bulletin，1966，77(4)：343–374.
[33] SHEA W T，KRONENBERG A K. Rheology and deformation mechanisms of an isotropic mica schist[J]. Journal of Geophysical Research: Solid Earth，1992，97(B11)：15 201–1 5237.
[34] LOGAN J M，RAUENZAHN K A . Frictional dependence of gouge mixtures of quartz and montmorillonite on velocity，composition and fabric[J]. Tectonophysics，1987，144(1/3)：87–108.
[35] TESEI T，COLLETTINI C，BARCHI M R，et al. Heterogeneous strength and fault zone complexity of carbonate-bearing thrusts with possible implications for seismicity[J]. Earth and Planetary Science Letters，2014，408：307–318.
[36] BARTON N. The shear strength of rock and rock joints[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1976，13(9)：255–279.
[37] SINGH M，RAJ A，SINGH B. Modified Mohr–Coulomb criterion for non-linear triaxial and polyaxial strength of intact rocks[J]. International Journal of Rock Mechanics and Mining Sciences，2011，48：546–555.
[38] SINGH M，SAMADHIYA N K，KUMAR A，et al. A nonlinear criterion for triaxial strength of inherently anisotropic rocks[J]. Rock Mechanics and Rock Engineering，2015，48(4)：1 387–1 405.
[39] 水利水电科学研究院. 岩石力学参数手册[M]. 北京：水利电力出版社，1991：448–459.(China Institute of Water Resources and Hydropower. Rock mechanics parameters handbook[M]. Beijing：Water Resources and Electric Power Press，1991：448–459.(in Chinese))
[40] TIEN Y M，KUO M C，JUANG C H. An experimental investigation of the failure mechanism of simulated transversely isotropic rocks[J]. International Journal of Rock Mechanics and Mining Sciences，2006，43(8)：1 163–1 181. |
|
|
|
2023, Vol. 42 
