مطالعه آزمایشگاهی و عددی خرابی در سنگ گرانیتی با استفاده از تانسور ترک مرتبه دوم

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشگاه تربیت مدرس

چکیده

یکــی از رویکردهــای مــورد اســتفاده در بررســی اثــرات تــرک بــر رفتــار محیــط ناپیوســته ســنگی، مطالعــه بــر روی محیـط پیوسـته معـادل محیـط ترک خـورده میباشـد. از جملـه ایـن روش هـا، روش مبتنـی بـر تانسـور تـرک اسـت کـه اثـرات هندســی حضــور ترک هــا شــامل انــدازه، امتــداد، و چگالــی عــددی آنهــا را در بــر می گیــرد. نوشــته حاضــر بــه رویکــرد جدیــد تعییـن تانسـور تـرک از مرتبـه دوم بـا اسـتفاده از آزمایشـات تعییـن سـرعت مـوج طولـی در محیـط پرداختـه و نیـز بـر نقـش آن در تسـهیل بررسـیها به عنـوان یـک رویکـرد جایگزیـن بـرای برداشـت های صحرایـی و نیـز مدل سـازی های عـددی کارا تا کیــد دارد. ماتریس هــای ســاختاری به دســت آمده در نوشــتار حاضــر امــکان بررســی رفتــار محیــط ناپیوســته ســنگی را بــا اسـتفاده از مدل سـازی عـددی بـر پایـه روش المـان محـدود در محیـط Matlab فراهـم سـاختند کـه نتایـج آن از تطابـق قابـل قبولـی بـا داده هـای آزمایشـگاه برخـوردار بـود. بدیهـی اسـت کـه بهبـود دقـت محاسـبات از طریـق افزایـش تعـداد نمونه هـای آزمایشــگاهی و به کارگیــری نتایــج حاصــل در برنامــه کامپیوتــری امکانپذیــر می باشــد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental and FEM Study on Damaged Granitic Rock Using Second Rank Crack Tensor

نویسندگان [English]

  • Kamran Panaghi
  • ali akbar golshani
Tarbiat Modares University
چکیده [English]

Any investigative approach towards rock behavior will necessitate inherent deficiencies such as pores and cracks to be taken into consideration. One of the methodologies employed to study cracked rock is to consider an equivalent continuum as for the domain with defects which will lend flexibility to experimental and numerical schemes due to its seamless effects on the constitutive relationships, hence reducing computational costs as well as experimental restraints in the laboratory. A case in point in such approach is the crack tensor model which is based upon the idea to represent cracks’ size, orientation, and number density as one single entity through which proper geometric characterization of the in-situ rock is carried out. Following the introduction of crack tensor concept and its application in the technical literature, the current work focuses on the determination of second rank crack tensor using P-wave velocity measurements on damaged granite. The benefit of such approach is emphasized via its role in boosting the degree of accuracy of the numerical analysis code developed in Matlab that implements different compliance matrices for four different stages of loading. The calculation results showed promising trends in agreement with those of the experimental data. Apparently, more experimental procedure is required to improve results’ accuracy in projects for which fulfilling more stringent regulatory requirements is a must.

کلیدواژه‌ها [English]

  • finite element method
  • P-wave velocity measurement
  • Crack tensor؛ Granitic rock؛ Matlab

مراجع

[1] R.E. Goodman, R.L. Taylor, T.L. Brekke, A model for the me- chanics of jointed rock, Journal of Soil Mechanics & Foundations Div, 1968.
[2] P. Cundall, A computer model for simulating systems, in:Proc. Symp. On Rock Fracture (ISRM), Nancy:[sn], 1971.
[3]   G.H. Shi, R.E. Goodman, Two dimensional discontinuous deformation analysis, International Journal for Numerical and Analytical Methods in Geomechanics, 9(6), pp. 541-556, 1985.
[4] B. Singh, Continuum characterization of jointed rock masses: Part I—The constitutive equations, in: International Journal of Rock Mechanics and Mining Sciences & Geomechanics Ab- stracts, Elsevier, pp. 311-335, 1973.
[5] T. Kyoya, Y. Ichikawa, T. Kawamoto, An application of damage tensor for estimating mechanical properties of rock mass,Journal of the Japan Society of Civil Engineers, pp. 27-35, 1985.
[6]  T. Sasaki, R. Yoshinaka, F. Nagai, A study of the multiple yield models on jointed rock mass by finite element method, in: Proceedings-Japan Society of Civil Engineers, pp. 59-59, 1994.
[7] A. Hojo, M. Nakamura, Y. Uchita, S. Sakurai, A design meth- od of rock bolts in jointed rock masses, in: Proceedings-Japan Society of Civil Engineers, pp. 143-154, 1996.
[8]   H. Yoshida, H. Horii, Micromechanics-based continuum model for rock masses and analysis of the excavation of under- ground power cavern, in: Proceedings-Japan Society of Civil En- gineers, pp. 23-42, 1996.
[9]  Y. Tasaka, H. Uno, T. Omori, K. Kudoh, Numerical analy- sis of underground powerhouse excavation considering strain softening and failure of joints, in: Proceedings of the 10th Japan Symposium on Rock Mechanics, pp. 575-580, 1998.
[10]  M. Oda, Fabric tensor for discontinuous geological materi- als, Soil Found., 22(4), pp. 96-108, 1982.
[11]  M. Oda, Permeability tensor for discontinuous rock masses, Geotechnique, 35(4), pp. 483-495, 1985.
[12]  A. Rouleau, J. Gale, Statistical characterization of the frac- ture system in the Stripa granite, Sweden, in: International Jour- nal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Elsevier, pp. 353-367, 1985.
[13]  M. Oda, Y. Hatsuyama, Y. Ohnishi, Numerical experiments on permeability tensor and its application to jointed granite at Stripa mine, Sweden, Journal of Geophysical Research: Solid Earth, 92(B8), pp. 8037-8048, 1987.
[14]  T. Takemura, M. Oda, Stereology-based fabric analysis of microcracks in damaged granite, Tectonophysics, 387(1), pp.131- 150, 2004.
[15] T. Takemura, M. Oda, H. Kirai, A. Golshani, Microstructural based time-dependent failure mechanism and its relation to geo- logical background, International Journal of Rock Mechanics and Mining Sciences, 53, pp. 76-85, 2012.
[16]   M. Oda, K. Suzuki, T. Maeshibu, Elastic compliance for rock-like materials with randon cracks, Soil Found., 24(3), pp. 27-40,1984.
[17] T. Takemura, A. Golshani, M. Oda, K. Suzuki, Preferred ori- entations of open microcracks in granite and their relation with anisotropic elasticity, International Journal of Rock Mechanics and Mining Sciences, 40(4), pp. 443-454, 2003.
[18] A. Golshani, M. Oda, Y. Okui, T. Takemura, E. Munkhtogoo, Numerical simulation of the excavation damaged zone around an opening in brittle rock, International Journal of Rock Mechanics and Mining Sciences, 44(6), pp. 835-845, 2007.
[19] K. Panaghi, A. Golshani, T. Takemura, Rock failure assess- ment based on crack density and anisotropy index variations dur-
ing triaxial loading tests, Geomechanics and Engineering, 9(6), pp. 793-813, 2015.
[20] T. Takemura, M. Oda, Changes in crack density and wave velocity in association with crack growth in triaxial tests of Inad  granite, Journal of Geophysical Research: Solid Earth, 110(B5), 2005.
[21] H. TADA, Prediction of deformation behavior of jointed rock mass around cavern considering stress dependency of joint stiffness, International Journal of the JCRM, 8(1), pp. 1-10, 2012.
نشریه مهندسی عمران امیرکبیر
دوره 51، شماره 3
مرداد و شهریور 1398
صفحه 415-424

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