بررسی تأثیر شدت درزه‌داری توده‌سنگ بر عملکرد سیستم‌های نگهداری در تونل با استفاده از مدلسازی عددی DFN-DEM (مطالعه موردی: تونل دسترسی سد رودبار لرستان)

نوع مقاله: پژوهشی

نویسندگان

دانشکده مهندسی معدن، نفت و ژئوفیزیک، دانشگاه صنعتی شاهرود

10.29252/anm.8.16.13

چکیده

در این مقاله، شبیه‌سازی DFN-DEM با استفاده از نرم­افزار المان مجزای سه‌بعدی PFC3D به منظور بررسی تاثیر تغییرات شدت درزه­داری توده‌سنگ بر عملکرد سیستم­های نگهداری تونل انجام شده است. این نرم‌افزار به دلیل توانایی ایجاد درزه‌های با اندازه محدود و با ویژگی‌های آماری مختلف و انعطاف‌پذیری در برابر شرایط مختلف و همچنین امکان مشاهده تخریب و ریزش‌های صورت گرفته به طور لحظه‌ای در طول تحلیل پایداری تونل، برای مدلسازی عددی در نظر گرفته شده است. در این مقاله، با تمرکز بر تونل دسترسی به گالری سد رودبار لرستان، ابتدا با استفاده از مدلسازی سیستم درزه‌های تصادفی مجزاDFN  و بر اساس خصوصیات برداشت شده از توده‌سنگ پیرامون تونل، شکستگی‌های منطقه در نرم‌افزار شبیه‌سازی شده و سپس با مدل سنگ بکر منطقه پیوند داده شده است. در ادامه عملکرد سیستم‌های نگهداری شاتکریت و قاب فولادی تونل نسبت به تغییر شدت درزه‌داری توده‌سنگ بررسی شده است. نتایج به دست آمده، نشان‌دهنده مقاومت بیش‌تر قاب فولادی نسبت به شاتکریت در برابر تغییر شدت درزه‌داری توده‌سنگ دربرگیرنده تونل است. آسیب جدی به سیستم نگهداری شاتکریت با دو برابر شدن تعداد درزه‌ها اتفاق می‌افتد، در حالی که در مورد قاب فولادی، تخریب جدی فضا با چهار برابر شدن تعداد درزه‌ها اتفاق می‌افتد. لذا در مواردی که انتظار افزایش شدت درزه‌داری بر اثر عوامل مختلفی چون انفجار، زلزله و غیره می‌رود، سیستم نگهداری قاب فولادی دارای قابلیت اعتماد بالاتری است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigate the effect of rock mass joint intensity on performance of support systems in the tunnel by using DFN-DEM numerical modeling (Case study: the access tunnel of Rudbar Lorestan Dam plant)

نویسندگان [English]

  • Mehdi Noroozi
  • Ramin Rafiei
  • Mehdi Bajolvand
  • Abedin Hojati Tavandashti
Dept. of Mining, Geophysics & Petroleum Shahrood University of Technology, Iran
چکیده [English]

Summary
In this paper, a DFN-DEM simulation using PFC3D software has been carried out to evaluate the effect of joint intensity variation on tunnel support systems performance. The obtained results indicated more resistance of steel frame against change of rock mass fracture intensity in relation to shotcrete.
 
Introduction
The geometric properties of joint sets, especially joint intensity, may be changed by various factors such as explosion, earthquakes, faulting etc. Therefore, it is essential to study the performance of tunnel support systems under various conditions of joint intensities. In this paper, by focusing on the access tunnel to the gallery of Rudbar Lorestan dam as a real case study, simulation of tunnel support systems and its surrounding rock mass close to the real condition using the DFN-DEM approach and PFC3D software is provided. Also for the first time, the dependence of the performance of shotcrete and steel frame to change the intensity of fracturing of rock mass, at this level of accuracy in simulation of jointed rock mass, has been investigated. Three dimensional distinct element software, PFC3D is considered for numerical modeling in this paper. This software has many advantages such as ability to create three-dimensional distinct joints with limited size and with different statistical characteristics, flexibility in different conditions and ability to monitor a momentarily caving and falling during tunnel stability analysis.
 
Methodology and Approaches
In this paper, at the first stage, by using the discrete fracture network (DFN) modeling and based on the surveyed data from the access tunnel, existing fractures in this region have been simulated in the PFC3D software. Then the model is linked with the intact rock model. Finally, the performance of tunnel support systems of shotcrete and steel frame relative to changes of the rock mass fracture intensity is investigated.
 
Results and Conclusions
Serious damage to Shotcrete support system occurs by doubling the number of joints, while serious damage occurs in the steel frame by quadrupling the number of joints. Therefore, by increasing joint intensity due to various factors such as explosions, earthquakes etc., the steel frame support system has higher reliability.

کلیدواژه‌ها [English]

  • Numerical modeling
  • Tunnel support system
  • joint intensity
  • PFC3D software
  • Rudbar Lorestan dam
[1]           Abrah, B., Faramarzi, L. (2012), Temporary support system design by experimental and numerical methods for ponstak tunnels of Rudbar Lorestan dam, 9th National Congress on Civil Engineering, Mashhad, (In Persian).
 
[2]           Golnari, S., Hamidvand, M., Vahedi, M., Mokhtari, M. (2014), Stability Analysis and Support Design of Garin Dam Water Diversion Tunnel, 1st National Conference of Architecture, Construction and Urban Environment, (In Persian).
[3]           Katsaga, T. (2016), Stability evaluation of underground opening using a Discrete Fracture Network Engineering (DFNE) approach. Itasca International Inc, Minneapolis, ISBN 978-0-09767577-4-0.
[4]           Palassi, M., Asadollahi, P. (2004), Design of Rockbolt and Shotcrete for Tunnels in Jointed Rock. 57th Canadian Geotechnical Conference, Quebec City.
[5]           Malmgren, L., Nordlund, E. (2008), Interaction of shotcrete with rock and rock bolts: a numerical study. International Journal of Rock Mechanics and Mining Sciences, 45(4), 538-553.
[6]           Hadjigeorgiou, J., Esmaieli, K., Grenon, M. (2008), Stability analysis of vertical excavations in hard rock by integrating a fracture system into a PFC model. Tunnelling and Underground Space Technology, 24(3), 296–308.
[7]           Li, L., Wu, A.X., Wang, Y.M.. (2013), Mechanism of wet shotcrete interacting with rock in support systems.  J. Cent. South Univ, 20(3), 821–829.
[8]           Roohparvar, F., Moadeli, A., Ebadi, M. (2014), Investigation of the effect of the structure and joints conditions of the rock mass on tunnel support system, 1st National Conference on Soil Mechanics and Foundation Engineering, Tehran, (In Persian).
[9]           Boon, C.W., Houlsby, G.T., Utili, S. (2015), Designing Tunnel Support in Jointed Rock Masses via the DEM. Rock Mechanics and Rock Engineering, 48(2), 603–632.
[10]         Yang, J.P., Chen, W.Z., Yang, D.S., Yuan, J.Q. (2015), Numerical determination of strength and deformability of fractured rock mass by FEM modeling, Computers and Geotechnics, 64, 20–31.
[11]         Yang, J.P., Chen, W.Z., Dai, Y.H., Yu, H.D. (2014), Numerical determination of elastic compliance tensor of fractured rock masses by FEM modeling, International Journal of Rock Mechanics & Mining Sciences, 70, 474–482.
[12]         Vallejos, J., Brzovic, A., Lopez, C., Bouzeran, L., Mas Ivars, D. (2013), Application of the Synthetic Rock Mass approach to characterize rock mass behavior at the El Teniente Mine, Chile, The 3rd International FLAC/DEM Symposium, Itasca Consulting Group, Hangzhou, China, p.15.
[13]         Second Report of Geology Engineering, (2007), Rudbar Lorestan Dam & Hydropower Plant, Iran Water & Power Resources development Co, (In Persian).
[14]         New Diversion Tunnel Report. (2013), Rudbar Lorestan Dam & Hydropower Plant. Iran Water & Power Resources development Co.
[15]         Noroozi, M., kakaei, R., jalali, S.E. (2015), Three-dimensional geometrical simulation of rock mass discontinuities network in the access tunnel of Rudbar Lorestan dam & hydropower plant, Tunneling & Underground Space Engineering, Volume 4, Issue 1, 53-68, (In Persian).
[16]         Itasca, (2010), PFC3D-Particle flow code in 3-dimensions, version 4.0, user’s manual, vols. I & II, Itasca Consulting Group, Inc.
[17]         Baddoo, N.R., Burgan, B.A. (2012), Structural design of stainless steel, The Steel Construction Institute, UK, SCI P29, ISBN 1 85942 116 4.