1استادیار؛ گروه مهندسی معدن؛ دانشکده‌ی مهندسی؛ دانشگاه کاشان
2دانشجوی کارشناسی ارشد استخراج معدن؛ دانشگاه کاشان
3دانشجوی دکترای تخصصی؛ رشته‌ی مهندسی معدن؛ گرایش مکانیک سنگ؛ دانشگاه صنعتی امیرکبیر؛ کارشناس شرکت مهندسی سپاسد
چکیده
مفاصل بین قطعات پوشش می‌توانند مقدار مشخصی از گشتاور خمشی، نیروی محوری و نیروی برشی را تحمل کنند. گزاره‌ی نیرو-جابجایی نیز در محدوده‌ی مشخصی از بار اعمالی می‌تواند تقریباً خطی در نظر گرفته شود. در تحلیل سازه‌ای پوشش سگمنتی، مفاصل می‌توانند به صورت لولاهای الاستیک مدل شوند و مشخصات سختی آن‌ها توسط صلبیت مفاصل بیان شود. این امر باعث می‌شود که گشتاور خمشی وارده بر پوشش کاهش یابد و با کاهش نیروهای داخلی وارده بر پوشش می‌توان از پوششی با ضخامت کمتر استفاده نمود. در این مقاله نیروهای وارده بر پوشش‌های سگمنتی باتوجه به اثر مفاصل در حالت‌های نسبت تنش افقی به قائم کوچک‌تر و بزرگ‌تر از یک در نظر گرفته شده است. روش تحلیلی برای ساختار مفاصل با تحلیل بر روی نسبت تنش افقی به قائم زمین، ضریب مقاوم توده‌سنگ، تاثیر سختی مفاصل، نحوه‌ی توزیع مفاصل و تعداد مفاصل انجام و گشتاور خمشی، نیروی محوری و جابجایی‌های پوشش تونل به علت نیروهای داخلی وارد بر پوشش محاسبه شده است. با توجه به نمودار اثر متقابل نیروی محوری و گشتاور خمشی پوشش، پوشش سگمنتی با ضخامت 30 سانتی‌متر برای تونل بلند انتقال آب سد سردشت با توجه به روش‌های تحلیلی و عددی برآورد شده است.
Segment Lining Design of the Long Tunnel for Transferring Water at Sardasht Dam Considering Segment Joints Effects
نویسندگان [English]
Hasan Bakhshandeh Amnieh1؛ Saeed Taei Semiromi2؛ Morteza Rahimi Dizadji3
1Assistant Professor; Department of Mining Engineering; Faculty of Engineering; University of Kashan
2MSc Student; Department of Mining Engineering; Faculty of Engineering; University of Kashan
3PhD Candidate; Faculty of Mining & Metallurgy; Amirkabir University of Technology; Sepasad Engineering Co.
چکیده [English]
In this research, the axial and shear force and bending moments in the segment lining of Sardasht dam water transfer tunnel are studied using both analytical and an explicit finite difference method, aiming to design a safe and stable lining. Segment joints and their characteristics such as stiffness and distribution pattern were considered as the principal modeling factors. The results indicate that the existing thickness of the tunnel lining is safe and provides the appropriate load and moment bearing capacity.
Introduction Segment joints of the lining should be capable of withstanding a certain amount of bending moment, and axial and shear forces. Considering that the force-displacement correlation may behave linearly within a certain range of the applied loads, the bending moment applied on the lining might be reduced. Hence, the lining thickness could be reduced once smaller internal forces are involved. In the structural analysis of the lining segment, joints could be modeled as elastic tubes and their stiffness could be expressed in terms of rigidity.
Methodology and Approaches In this article, considering the rigidity of the lining segments, the lining joints are modeled as elastic tubes with constant rigidity. Analytical methods for analysis of the lining joints are based on the ratio of horizontal to vertical stresses, soil strength coefficient, the influence of joint stiffness, number and distribution of joints. Bending moment, axial force and the lining displacements due to the internal forces applied on the lining are calculated. Axial force and bending moment applied on the lining have been evaluated using the FLAC software program. Hence the graph of axial force versus bending moment of the lining is plotted considering that the bending moment and axial forces applied on the lining are evaluated using both analytical and numerical methods.
Results and Conclusions In the numerical method, all combinations of bending moments and axial forces applied to the lining segment at Sardasht long tunnel were transferred to the reciprocating effect diagram, to evaluate its safe application. The safety factor for both continuous and segmental lining was found to be 2.22 and 3.14, respectively. Hence all selected linings were found to be safe. In the numerical method, the axial force and bending moments applied to the tunnel lining were determined at three different ratios of (horizontal stress/vertical stress) and they were found to be 0.7, 1.0 and 1.3. Their combinations were found to be within the acceptable regions in the reciprocating effect diagram. Hence, one can conclude that a 30cm thickness for the segment lining is stable and safe within the limits considered.
کلیدواژه ها [English]
Water Transfer Tunnel, Segment lining design, Joint, Internal load
مراجع
[1] Kim, S. H., Pelizza, S., & Kim, J. S. (2006). A study of Strength Parameters in the Reinforced Ground by Rock Bolts. Tunneling and Underground Space Technology, 21(3-4), 378-379. http://dx.doi.org/10.1016/j.tust.2005.12.192.
[2] Kim, H. J., & Eisenstein, Z. (2006). Prediction of Tunnel Lining Loads Using Correction Factors. Engineering Geology, 85 (3-4), 302-312. http://dx.doi.org/10.1016/j.enggeo.2006.03.001.
[4] Lee, K. M., & Ge, X. W. (2001). The Equivalent of The Jointed Shield Driven Tunnel Lining to A Continuous Ring Structure. Canadian Geotechnical Journal, 38(3), 461-483. http://dx.doi.org/10.1139/t00-107.
[5] Lee, K. M., & Hou, X. Y., Ge. X. W., Tang. Y. (2001). An Analytical Solution for A Jointed Shield-Driven Tunnel Lining. International Journal for Numerical and Analytical Methods in Geomechanics, 25(4), 365-390. http://dx.doi.org/10.1002/nag.134.
[6] Koyama, Y. ( 2003). Present Status and Technology of Shield Tunneling Method in Japan. Tunneling and Underground Space Technology, 18(2-3), 145-159. http://dx.doi.org/10.1016/S0886-7798(03)00040-3.
[7] Lu, L., Lu, X., & Fan, P. (2011). Full-Ring Experimental Study of The Lining Structure of Shanghai Changjiang Tunnel. Civil Engineering and Architecture, 45(8), 732-739. ISSN :1934-7359.
[8] Xiaochun, Z., Wei, Z., Zhengrong, H., & Yuewang, H. (2006). Effect of Joint Structure on Joint Stiffness for Shield Tunnel Lining. Tunneling and Underground Space Technology, 21(3-4), 406-407. http://dx.doi.org/10.1016/j.tust.2005.12.215.
[9] Teachavorasinskun, S., & Chub-uppakarn, T. (2010). Influence of Segmental Joints on Tunnel Lining. Tunnelling and Underground Space Technology, 25(4), 490-494. http://dx.doi.org/10.1016/j.tust.2010.02.003.
[10]مختاریان، م.، جعفری، ا.، و اسماعیلی، م. (1388). تحلیل پایداری پوشش سگمنتی تونل خط 2 قطار شهری تبریز. هشتمین کنفرانس تونل ایران (ص. 215- 211). تهران، ایران: دانشگاه تربیت مدرس. شابک: 5540-1735.
[11] Hefny, A. M., & Chua, H. C. (2006). An Investigation into the Behaviour of jointed Tunnel Lining. Tunnelling and Underground Space Technology, 21(3-4), 428-436. http://dx.doi.org/10.1016/j.tust.2005.12.070.
[12] Roland, W. (2000). Steel Fibre Reinforced Tunnel Segments for The Application in shield Driven Tunnel Lining (pp. 35-44). Netherland: Doctoral Thesis, Delft University of Technology. ISBN:90-407-1965-9.
ابتدای صفحه