ارزیابی شاخص شکنندگی S20 سنگ آهک و بررسی عوامل موثر بر آن در حالت خشک و اشباع

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه زمین شناسی، دانشکده علوم، دانشگاه فردوسی مشهد، مشهد، ایران

2 استاد/ گروه زمین شناسی، دانشکده علوم، دانشگاه فردوسی مشهد، مشهد، ایران

چکیده

شکنندگی یکی از مسائل مهم در حفاری سنگ است. تاکنون روش های مختلفی برای تعیین شکنندگی سنگ معرفی شده است اما روشی برای اندازه گیری آن به عنوان استاندارد مطرح نشده است. در این مقاله، یک مطالعه تجربی برای ارائه روشی قابل اعتماد برای پیش بینی شاخص شکنندگی S20 صورت گرفته است. آزمایش تعیین شاخص شکنندگی S20 برای 35 بلوک سنگ آهک برداشت شده از نقاط مختلف ایران، در حالت خشک و اشباع انجام شد. به علاوه، خصوصیات فیزیکی (چگالی خشک، تخلخل، مقاومت الکتریکی، عدد سختی بازگشتی اشمیت و درصد جذب آب)، مکانیکی (مقاومت فشاری تک محوری و شاخص بار نقطه ای) و دینامیکی (سرعت موج برشی و تراکمی) اندازه گیری شد. در نهایت، رده بندی نمونه ها بر اساس مطالعات سنگ شناسی و کانی شناسی انجام شد و مطالعات آماری برای هر رده صورت گرفت. بر اساس نتایج، پیش بینی شاخص شکنندگی S20 بر اساس رده بندی ارائه شده از اطمینان بالایی برخوردار است. به علاوه، با بررسی شکنندگی نمونه ها در حالت خشک و اشباع مشخص شد که وجود کانی رسی مونتموریلونیت باعث افت شکنندگی و وجود ریزترک های درون دانه ای و تخلخل بالا باعث افزایش مقدار شکنندگی در حالت اشباع نسبت به خشک می شود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation S20 brittleness index of limestone and effective parameters on it at dry and saturated states

نویسندگان [English]

  • Sajad Safari Farrokhad 1
  • Gholam Reza Lashkaripour 2
  • Nasser Hafezi Moghaddas 2
1 Department of geology, Faculty of science, Ferdowsi University of Mashhad, Mashhad, Iran
2 Professor Department of geology, Faculty of science, Ferdowsi University of mashhad, Mashhad, Iran
چکیده [English]

Brittleness is an important problem in rock boring. So far, various methods have been introduced for determining rock brittleness but no method has yet been standard to measure it. In this paper, an empirical study was done to provide a reliable method for predicting the S20 brittleness index. The S20 brittleness test was done for 35 limestone blocks pick out from different parts of Iran in dry and saturated state. In addition, physical (dry density, porosity, electrical resistivity, Schmidt rebound hardness number and water absorption), mechanical (uniaxial comprehensive strength and point load index) and dynamical properties (P and S wave velocity) was measured. Finally, the classification of the samples was done based on the studying of petrography and mineralogy and statistical studies were done for each class. According to the results, predicting S20 based on the provided classification has a high degree of certainty. In addition, by studying the brittleness of the samples in dry and saturated state, it was determined that the presence of Montmorillonite clay mineral causes a decrease of brittleness and the presence of intergranular micro cracks and high porosity leads to an increase brittleness in the saturation state relative to dry state.

کلیدواژه‌ها [English]

  • S20 brittleness index
  • Rock boring
  • Montmorillonite
  • Petrography
  • Limestone
قادرنژاد، ص.، لله­گانی دزکی، سعید.، نجاتی، ح.ر.، علی­پنهانی، ب.، 1397. ارائه شاخصی جدید برای ارزیابی تردی سنگ. نشریه مهندسی منابع معدنی، 3: 43-55.
وفائیان، م.، 1387. خواص مهندسی سنگ­ها: تئوریها و کاربردهای اجرائی. انتشارات ارکان دانش. 61-60.
Altindag, R., 2002. The evaluation of rock brittleness concept on rotary blast hold drills. Journal of the Southern African Institute of Mining and Metallurgy, 102: 61-66.
Altindag, R., Guney, A., 2010. Predicting the relationships between brittleness and mechanical properties (UCS, TS and SH) of rocks. Scientific Research and Essays, 5: 2107-2118.
Armaghani, D. J., Mohamad, E. T., Narayanasamy, M. S., Narita, N., Yagiz, S. 2017. Development of hybrid intelligent models for predicting TBM penetration rate in hard rock condition. Tunnelling and Underground Space Technology, 63: 29-43.
Bamford, W., 1984. Rock test indices are being successfully correlated with tunnel boring machine performance.  Fifth Australian Tunnelling Conference: State of the Art in Underground Development and Construction; Preprints of Papers. Institution of Engineers, Australia, 218p.
Bieniawski, Z., Grandori, R., 2007. Predicting TBM excavability-part II. Tunnels and Tunnelling International.
Blindheim, O., Bruland, A., 1998. Boreability testing. Norwegian TBM Tunnelling, 30: 29-34.
Blindheim, O., Grov, E., Nilsen, B., 2002. The effect of mixed face conditions (MFC) on hard rock TBM performance.  AITES-ITA Downunder 2002: 28th ITA General Assembly and World Tunnel Congress, Sydney, Australia, 2-8.
Bruland, A., 1999. Hard rock tunnel boring advance rate and cutter wear. Norwegian Institute of Technology (NTNU), Trondheim, Norway.
Coates, D., Parsons, R., 1966. Experimental criteria for classification of rock substances.  International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,  Elsevier, 181-189.
Dahl, F., Bruland, A., Jakobsen, P. D., Nilsen, B., Grov, E., 2012. Classifications of properties influencing the drillability of rocks, based on the NTNU/SINTEF test method. Tunnelling and Underground Space Technology, 28: 150-158.
Dunham, R. J., 1962. Classification of carbonate rocks according to depositional textures. AAPG Bulletin, 1: 80-121.
Embry, A. F., Klovan, J. E., 1971. A late Devonian reef tract on northeastern Banks Island, N.W.T. Bulletin of Canadian Petroleum Geology, 19: 730-781.
Farmer, I., Glossop, N., 1980. Mechanics of disc cutter penetration. Tunnels and Tunnelling, 12: 22-25.
Frough, O., Khetwal, A., Rostami, J., 2019. Predicting TBM utilization factor using discrete event simulation models. Tunnelling and Underground Space Technology, 87: 91-99.
Gale, F., 2009. Screening criteria for shale-gas systems. Gulf Coast Assoc. Geol. Soc. Trans, 59: 779-793.
Genis, M., Basarir, H., Ozarslan, A., Bilir, E., Balaban, E., 2007. Engineering geological appraisal of the rock masses and preliminary support design, Dorukhan Tunnel, Zonguldak, Turkey. Engineering Geology, 92: 14-26.
George, E., 1995. Brittle failure of rock material-test results and constitutive models. AA Balkema/Rotterdam/Brolkfield: 123-128.
Hetenyi, M. I., 1966. Handbook of Experimental Stress Analysis. 15p.
Hucka, V., Das, B., 1974. Brittleness determination of rocks by different methods.  International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, Pergamon, 389-392.
ISRM 1981. Rock characterization, testing and monitoring, Oxford, Pergamon press.
ISRM 1985. Suggested method for determining point load strength.  International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, Elsevier, 51-60.
ISRM 2007. The complete ISRM suggested methods for rock characterization, testing and monitoring: 1974-2006. Suggested methods prepared by the commission on testing methods., Ankara, International Soc. for Rock Mechanics, Commission on Testing Methods.
Jarvie, D. M., Hill, R. J., Ruble, T. E., Pollastro, R. M., 2007. Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment. AAPG Bulletin, 91: 475-499.
Kahraman, S., 2002. Correlation of TBM and drilling machine performances with rock brittleness. Engineering Geology, 65: 269-283.
Koopialipoor, M., Nikouei, S. S., Marto, A., Fahimifar, A., Armaghani, D. J., Mohamad, E. T., 2018. Predicting tunnel boring machine performance through a new model based on the group method of data handling. Bulletin of Engineering Geology and the Environment, 1-15.
Macias, F., Dahl, F., Bruland, A., Tunnelling, I., Association, U. S., 2017. Applicability of the new rock abrasivity test method (RIAT) to cutter life assessments in hard rock tunnel boring.  World Tunnel Congress, 1-10.
Matern, N. V., Hjelmér, A., 1943. Försök med pågrus, Statens Väginstitut.
Morley, A., 1944. Strength of Material. Longman, Green, London.
Meng, F., Zhou, H., Zhang, C., Xu, R., Lu, J. 2015. Evaluation methodology of brittleness of rock based on post-peak stress–strain curves. Rock Mechanics and Rock Engineering, 48, 1787-1805.
Nejati, H., Moosavi, S. A., 2017. A new brittleness index for estimation of rock fracture toughness. Journal of Mining and Environment, 8: 83-91.
Nelson, P., Ingraffea, A., O'rourke, T., 1985. TBM performance prediction using rock fracture parameters. Intl J of Rock Mech and Mining Sci and Geomechanic Abs, 22.
Obert, L., Duvall, W. I., 1967. Rock mechanics and the design of structures in rock. J. Wiley.
OZDEMIR, L., and WANG, F. D., 1979. Mechanical tunnel boring prediction and machine design. Nasa Sti/Recon Technical Report N, 80p.
Protodyakonov, M., 1962. Mechanical properties and drillability of rocks.  Proceedings of the Fifth Symposium on Rock Mechanics, University of Minnesota, Minneapolis, MN, 103-118.
Ramsay, J. G., 1967. Folding and fracturing of rocks. Mc Graw Hill Book Company, 568p.
Salimi, A., Faradonbeh, R. S., Monjezi, M., Moormann, C., 2018. TBM performance estimation using a classification and regression tree (CART) technique. Bulletin of Engineering Geology and the Environment, 77: 429-440.
Sumner, ME., Naidu, R., 1998. Sodic soils distribution, properties, management, and environmental consequences. Oxford University. Press, New York.
Woan, G. 2000. The Cambridge handbook of physics formulas, Cambridge University Press, pp. 147.
Yagiz, S., 2009. Assessment of brittleness using rock strength and density with punch penetration test. Tunnelling and Underground Space Technology, 24: 66-74.
Yarali, O., Kahraman, S., 2011. The drillability assessment of rocks using the different brittleness values. Tunnelling and Underground Space Technology, 26: 406-414.
Yarali, O., Soyer, E., 2011. The effect of mechanical rock properties and brittleness on drillability. Scientific Research and Essays, 6: 1077-1088.