مدل‌سازی عددی تاثیر فاصله‌داری و زاویه داری درزه Y شکل نزدیک بار کششی میل مهار بر رشد ترک

نوع مقاله: یادداشت فنی

نویسندگان

1 استادیار، گروه مهندسی معدن، دانشگاه صنعتی همدان

2 کارشناسی ارشد استخراج معدن، گروه مهندسی معدن، دانشگاه صنعتی همدان

چکیده

ابعاد حفریات زیرزمینی یکی از پارمترهای کلیدی در پایداری آن است. در توده‌سنگ‌های ضعیف، حفریات بزرگ زمان پایداری کمی دارند بطوری که این زمان از زمان نصب نگهداری کمتر است. راک‌بولت‌ها به عنوان یکی از سیستم‌های نگهداری در پایدارسازی پروژه‌های مهندسی سنگ کاربرد دارند. نقش اصلی راک‌بولت‌ها، افزایش مقاومت زمین است. عملکرد راک‌بولت‌ها به کیفیت نصب آن‌ها بستگی دارد. با استفاده از روش‌های کشش راک‌بولت و تست گشتاور می‌توان از کیفیت نصب راک‌بولت مطلع شد. شبیه‌سازی‌های عددی از دیگر از روش‌هایی است که برای مطالعه رفتار راک‌بولت کاربرد دارند. در این روش‌ها می‌توان رفتار پیچیده راک‌بولت را که با مطالعه آزمایشگاهی امکان‌پذیر نیست، مطالعه کرد. در این مقاله سعی شده است که با استفاده از نرم‌افزار franc 2d تاثیر نیروی وارده از طرف راک‌بولت بر روی درزه Yشکل مدلسازی شود. زاویه درزه بزرگ نسبت به افق (β) صفر، 45 و 90 درجه است. زاویه درزه کوچک نسبت به درزه بزرگ (α)، 20، 40، 60، 80، 100، 120، 140 و 160 درجه است.  فاصله درزه از مرکز محل اعمال نیرو 2a، 3a و 4a است که a طول درزه بزرگ است. در این پژوهش 52 مدل مورد بررسی قرار گرفت. در حالتی که درزه افقی باشد بیشترین و در حالت قائم کمترین رشد درزه دیده می‌شود. بیشترین تعداد رشد درزه نیز در حالتی است که زاویه درزه بزرگ نسبت به افق 45 درجه باشد. بیشترین گسترش رشد شاخه کوچک در حالت افقی و بیشترین تعداد رشد شاخه کوچک درزه نیز در زاویه 45 درجه نسبت به افق اتفاق افتاده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Simulation of the Effect of Spacing and Angularity of Y Shape Joint Neighboring Rock Bolt Tensile Load on the Crack Growth

نویسندگان [English]

  • V. Sarfarazi 1
  • M.R. Ajamzadeh 2
1 Assistant Professor, Dept. of Mining, Hamedan University of Technology
2 M.Sc Student, Dept. of Mining, Hamedan University of Technology
چکیده [English]

The dimension of underground structure is a key factor in its stability. Rock blotting has important effect in rock mechanic projects. It increases the stability of rock blocks. The performance of rock bolt is depending on the quality of its set up. Quality of its set up is determined by pull out test method. Numerical simulation is other method for determination of rock blotting behavior. In this paper, the effect of tensile loading on the “Y” shape joint is determined using FRANC2D. The angularity of large joint tail (β) changes from 0° to 90° with increment of 45°. The angularity of small joint tail related to large joint tail (α) changes from 20° to 160° with increment of 20°. The spacing between joint and loading place change from 2a to 4a with increment of “a” which “a” is the length of large joint tail. Totally 52 model were simulated. In the case of horizontal joint the crack growth length is maximum and vertical joint has minimum effect on the crack growth. When the angularity of large joint tail related to horizontal was 45°, the maximum of crack growth was occurred. The maximum of crack growth from small joint tail was occurred when it is in horizontal configuration. The maximum number of small joint tail growth occurred when its angularities related to horizontal axis was 45°.

کلیدواژه‌ها [English]

  • rock bolt
  • Y shape joint
  • crack growth
  • angularity
  • spacing
[1]  سرفرازی، و.، عجم‌زاده، م. ر.، شیرکوند، ر.؛ 1394؛"تاثیر بار کششی راکبولت بر رفتار برشی درزه با زاویهداری مختلف". دومین کنفرانس ملی مکانیک خاک و مهندسی پی، دانشگاه صنعتی قم، ص 30-22.

[2]  عجم‌زاده، م. ر.، سرفرازی، و.؛ 1394؛"مدلسازی عددی بررسی تاثیر بارراکبولت بر رشد ترک از درزههایYشکل". دومین کنفرانس ملی مکانیک خاک و مهندسی پی، دانشگاه صنعتی قم، ص 56-63.

[3]     Choquet, P. (1989). “Rock bolting practical guide”. Ottawa: CANMET, Balkema, 88–95.

[4]     Seeber, G. (1972). “Suggested Methods forDetermining Rock bolt Tension Using a TorqueWrench”. International Society for Rock Mechanics Committee on Standardization (ISRM), 221-231.

[5]     Kaiser, P. K., Yazici, S., and Nose, J. (1992). “Effect of stress change on thebond strength off ully grouted cables”. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 29: 293–305.

[6]     Stillborg, B. (1986). “Professional users for rock bolting”. Ser. Rock and Soil Mechanics, 31(4): 165-172.

[7]     Reichert, R. D, Bawden, W. F., and Hyett, A. J. (1991). “Evaluation ofdesignbolt bond strength for fully grouted bolt”. 93rd Annual Meeting of CIM, Vancouver, 169-181.

[8]     Ito, F., Nakahara, F., Kawano, R., Kang, S., and Obara, Y. (2001). “Visualisation off ailure in a pull-out of cable bolts using X-rayCT”. Construction Build Mater, 15: 263–270.

[9]     Hyett, A. J., Bawden, W. F., and Reichert, R. D. (1992). “The effect of rockmass confinement on the bond strength of fully grouted cable bolts”. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 29: 503–524.

[10]  Chappell, B. A. (1989). “Rock bolts and shear stiffness in jointed rockmass”. Journal of Geotechnical Engineering, 21(3): 134-140.

[11]  Franklin, J. A., and Dusseault, M. B. (1989). “Rock Engineering”. McGraw-Hill Publishing Company, New York.

[12]  Freeman, T. J. (1978). “The behavior of fully-bonded rock bolts in theKielder experimental tunnel”. Tunnels Tunneling, 37–40.

[13]  Sun, X. (1984). “Grouted rock bolt used in underground engineering in softsurrounding rock or in highly stressed regions”. In Stephansson, O., editor, Proceedings of the International Symposium on Rock Bolting, Rotterdam: Balkema, 93–9.

[14]  Tao, Z., and Chen, J. X. (1984). “Behavior of rock bolting as tunneling support”. In Stephansson, O., editor, Proceedings of the International Symposium on Rock Bolting, Rotterdam: Balkema, 87–92.

[15]  Indraratna, B., and Kaiser, P. K. (1990). “Analytical model for the design ofgrouted rock bolt”. International Journal for Numerical and Analytical Methods in Geomechanics, 227–51.

[16]  Jiang, Y. J., Esaki, T., and Yokota, Y. (1995). “The mechanical effect of groutedrock bolts on tunnel stability”. Journal of Construction Engineering and Management, 28(4): 154-164.

[17]  Li, C., and Stillborg, B. (1999). “Analytical models for rock bolts”. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 36: 1013–129.

[18]  Bj ornfot, F., and Stephansson, O. (1984). “Interaction of grouted rock bolts andhard rock masses at variable loading in a test drift of theKiirunavaara Mine, Sweden”. In Stephansson, P., editor, Proceedings of the International Symposium on rock bolting, Rotterdam: Balkema, 377–95.

[19]  Madhav, M. R., Gurung, N., and Iwao, Y. (1998). “Atheoretica l model for pulloutresponse of extensible reinforcements”. Geosynthetics International, 5(4): 399–424.

[20]  Gurung, N. (2001). “1-D analytical solution for extensible and inextensiblesoil/rock reinforcement in pull-out tests”. Geotextiles Geomembranes, 19: 195–212.

[21]  Cox, H. L. (1952). “The elasticity and strength of paper and other fibrousmaterials”. British Journal of Applied Physics, 3: 72–79.

[22]  Abramento, M., and Whittle, J. A. (1995). “Analysis of pullout tests for planarreinforcements in soil”. Journal of Geotechnical Engineering, 121(6): 476–85.

[23]  Kovari, K. (2003). “History of the sprayed concrete lining method-part II:milestones up to the 1960s”. Tunn Undergr Space Technol, 18: 71–83.

[24]  Endersbee, L. A. (1999). “The snowy vision and the young team—the first decade of engineering for the snowy mountains scheme”. The Spirit of the Snowy—Fifty Years On, Cooma, Australia, 39–58.

[25]  Bjurstro¨m, S. (1974). “Shear strength of hard rock joints reinforced by grouted untensioned bolts”. 3rd ISRM Congress, Denver, USA, 1194–1199.

[26]  Pells, P. J. N. (1974). “The behaviour of fully bonded rockbolt”.. 3rd ISRM Congress, Denver, USA, 1212–1217.

[27]  Farmer, I. W. (1975). “Stress distribution along a resin grouted rock anchor”. International Journal of Rock Mechanics and Mining Sciences, 12: 347–351.

[28]  Dunham, D. K. (1976). “Anchorage tests on strain gauged resin bonded bolts”. Tunnels Tunnelling, 8: 73–6.

[29]  Hibino, S., and Motijama, M. (1981). “Effects of rock bolting in jointy rock”. International Symposium on Weak Rock, Tokyo, Japan, 1057–1062.

[30]  Dight, P. M. (1982). “Improvements to the stability of rock walls in open pit mines”. Ph.D., Monash University, Australia, 189-195.

[31]  Gaziev, E. G., and Lapin, L. V. (1983). “Passive anchor reaction to shearing stress on a rock joint”. International Symposium on Rock Bolting, Abisko, Sweden, 101–108.

[32]  Stillborg, B. (1984). “Experimental investigation of steel cables for rock reinforcement in hard rock”. Ph.D., Lulea University, Sweden, 248-255.

[33]  Dight, P. M. (1983). “A case study of the behaviour of rock slope reinforced with fully grouted rock bolts”. International Symposium on Rock Bolting, Abisko, Sweden, 523–38.

[34]  Lunardi, P. (2000). “The design and construction of tunnels using the approach based on the analysis of controlled deformation in rocks and soils”. http://www.rocksoil.com/p_d_f/t_and_t_rocksoil_supp.pdf.

[35]  Lunardi, P. (1994). “Progetto e costruzione di gallerie secondo l’approccio basato sull’analisi delle deformazioni controllate nelle rocce e nei suoli. Parte 1”. Quarry and Construction, 3: 21–36.

[36]  Lunardi P. (1995). “Preconfinement of an excavation in relation to new orientations forward the design and construction of tunnels”. Gallerie e grandi opere sotterranee, 45: 16–37.

[37]  Lunardi, P. (1995). “Progetto e costruzione di gallerie secondo l’approccio basato sull’analisi delle deformazioni controllate nelle rocce e nei suoli Parte 2”. Quarry Construction, 3: 113–36.

[38]   Aldorf, J., and Exner, K. (1986). “Mine Openings: Stability and Support”. Elsevier, Oxford, Amsterdam, Tokyo.

[39]  Hoek, E., and Wood, D. F. (1989). “Rock Support”. Mineralogical Magazine,12(5): 33-45.

[40]  Indraratna, B., and Kaiser, P. K. (1990). “Design for grouted rock bolts basedon the convergence control method”. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 27: 269–281.

[41]  Beard, M. D., and Lowe, M. J. S. (2003). “Non-destructive testing of rock bolts using guided ultrasonic waves”. International Journal of Rock Mechanics & Mining Sciences, 40: 527–536.

[42]  Guan, Zh., Jiang, Y., Tanabasi, Y., and Huang, H. (2007). “Reinforcement mechanics of passive bolts in conventional tunneling”. International Journal of Rock Mechanics & Mining Sciences, 44: 625–636.

[43]  Zou, D. H., Cui, Y., Madenga, V., and Zhang, C. (2007). “Effects of frequency and grouted length on the behavior of guided ultrasonic waves in rock bolts”. International Journal of Rock Mechanics & Mining Sciences, 44: 813-819.

[44]  Ivanovic, A. D., and Neilson, R. (2008). “Influence of geometry and material properties on the axial vibration of a rock bolt”. International Journal of Rock Mechanics & Mining Sciences, 45: 941–951.

[45]  Chunlin Li, Ch. (2010). “A new energy-absorbing bolt for rock support in high stress rock masses”. International Journal of Rock Mechanics & Mining Sciences, 47: 396–404.

[46]  Deb, D. C., and Das, K. (2011). “Modelling of fully grouted rock bolt based on enriched finite element method”. International Journal of Rock Mechanics & Mining Sciences, 48: 283–293.

[47]  Chen, Y. (2014). “Experimental study and stress analysis of rock bolt anchorage Performance”. Journal of Rock Mechanics and Geotechnical Engineering, 6: 428-437.

[48]  Cao, Ch., Ren, T., Cook, Ch., and Cao, Y. (2014). “Analytical approach in optimising selection of rebar bolts in preventing rock bolting failure”. International Journal of Rock Mechanics & Mining Sciences, 72: 16–25.

[49]  Nemcik, J., Ma, Sh., Aziz, N., Ren, T., and Geng, X. (2014). “Numerical modelling of failure propagation in fully grouted rock bolts subjected to tensile load”. International Journal of Rock Mechanics & Mining Sciences, 71: 293–300.

[50]  Kristjánsson, G. (2014). “Rock bolting and pull out test on rebar Bolts”. Norwegian University of Science and Technology, 342-355.

[51]  Kang, H., Yang, J., Meng, X. (2015). “Tests and analysis of mechanical behaviours of rock bolt components for China’s coal mine roadways”. Journal of Rock Mechanics and Geotechnical Engineering, 7: 14-26.

[52]  Changxing, Zh., Xu, Ch., Youdong, M., and Xulin, L. (2015). “Modeling of grout crack of rockbolt grouted system”. International Journal of Mining Science and Technology.