اثرات جهت موج زلزله بر پاسخ دینامیکی سدهای خاکی- مطالعه‌ی موردی: سد شهدا

نوع مقاله : مقاله پژوهشی

نویسنده

دانشکده مهندسی، دانشگاه صنعتی کرمانشاه، کرمانشاه، ایران

چکیده

در این مقاله اثرات نامنظمی در جهات اولیه بارگذاری‌های لرزه‌ای بر پاسخ‌های تاریخچه-زمانی غیرخطی سد شهدا مطالعه شده است. حداکثر مقطع عرضی سد، در شرایط تراز نرمال دریاچه آن، توسط روش اجزای محدود دو بعدی شبیه‌سازی شده است. رکورد شتاب زلزله نزدیک-گسل طبس به عنوان بارگذاری دینامیکی به مدل‌های عددی اعمال شده است. سه الگوی اصلی بارگذاری جهتی افقی، قائم و مایل برای بررسی اثرات جهات اولیه انتشار حرکات لرزه‌ای در نظر گرفته شده است. در هر مورد پاسخ‌های لرزه‌ای نسبت به مورد مرجع بارگذاری در جهت افقی بالا دست به پایین دست مخزن مقایسه شده است. برای مد‌ل‌سازی مصالح بدنه و پی سد به ترتیب از مدل رفتاری خاک سخت شونده با کرنش کوچک HS-small و مدل ارتجاعی-خمیری کامل مور-کولمب استفاده شده است. اهمیت و ضرورت انجام این تحقیق در تقریب محافظه‌کارانه شبیه‌سازی شرایط بارگذاری سه بعدی در تحلیل‌های عددی دو بعدی است. تا به حال در اغلب مدل‌های دو بعدی، راستای اولیه حرکات لرزه‌ای ورودی فقط در جهات و افقی یا قائم بوده است، که در این تحقیق سعی شده که این الگو با حالات ممکن دیگر بارگذاری جهتی، مقایسه شود. نتایج مطالعه حاضر نشان می‌دهد که حالت بارگذاری لرزه‌ای با جهت انتشار اولیه مایل، با زاویه 45 درجه، بیشترین اثر بر پاسخ‌های لرزه‌ای سد نسبت به حالات بارگذاری افقی یا قائم را ایجاد می‌کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effects of Earthquake Wave Direction on Dynamic Response of Earth Dams - Case Study: Shohada Dam

نویسنده [English]

  • Yazdan Shams Maleki
Kermanshah university of technology
چکیده [English]

In this paper, the irregularity effects in the initial directions of the seismic loading on the nonlinear time-history responses of the Shohada dam have been investigated. The maximum cross-section of the dam has been simulated by the 2D finite element method under normal lake-level conditions. The near-fault acceleration record of the Tabas earthquake has been applied as dynamic input motion to the two-dimensional numerical models. Numerical analysis has been conducted in the Newmark explicit time integration scheme framework. The main three patterns of horizontal, vertical, and oblique directional seismic loading are considered to investigate the effects of the initial directions of seismic motion propagation. In each case, the seismic responses are compared to the conventional seismic loading responses in the horizontal direction from the upstream (reservoir) to the downstream of the dam. The hardening soil model with small strain (HS-small) and the Mohr-Coulomb model were used to model the dam's body and the foundation materials, respectively. In most 2D simulations, the initial direction of the input seismic movements has been only in one or two dimensions and in the horizontal or vertical orientation. This study has attempted to compare these traditional seismic loading patterns with other possible states in 2D numerical models. The present study results show that the seismic loading mode with the initial direction of inclination of 45 degrees has the worst and most significant effect on the seismic response of the dam compared to the traditional method of horizontal loading.

کلیدواژه‌ها [English]

  • Irregular input motions
  • Seismic loading
  • Earth dam
  • Non-linear analysis
  • Constitutive model
[1] S. Sica, L. Pagano, F. Rotili, Rapid drawdown on earth dam stability after a strong earthquake, Computers and Geotechnics, 116 (2019) 103187.
[2] K. Jeong, S. Shibuya, T. Kawabata, Y. Sawada, H. Nakazawa, Seismic performance and numerical simulation of earth-fill dam with geosynthetic clay liner in shaking table test, Geotextiles and Geomembranes, (2) (2020) 190-197.
[3] F. Castelli, V. Lentini, C.A. Trifarò, 1D seismic analysis of earth dams: the example of the Lentini site, Procedia Engineering, 158 (2016) 356-361.
[4] R. Pang, B. Xua, X. Kong, D. Zoua, Y. Zhou, Seismic reliability assessment of earth-rockfill dam slopes considering strain-softening of rockfill based on generalized probability density evolution method, Soil Dynamics and Earthquake Engineering, 107 (2018) 96-107.
[5] X. Yang, S. Chi, Seismic stability of earth-rock dams using finite element limit analysis, Soil Dynamics and Earthquake Engineering, 64(2014) 1-10.
[6] L. Masini, S. Rampello, R. Donatelli, Seismic performance of two classes of earth dams, Earthquake Engng Struct Dyn, 2020.
[7] H. Sharafi, Y. Shams Maleki, Evaluation of hazardous effects of near‑fault earthquakes on earth dams by using EL and TNL numerical methods (case studies: Gheshlagh Oleya and Jamishan dams), Natural Hazards, 2019.
[8] Y. Gao, L. Wang, D. Lib, Y. Gao, Evaluation of valley topography effects on the seismic stability of earth rockfill dams via a modified valley topography coefficient, Computers and Geotechnics, 128 (2020) 103814.
[9] L. Pelecanos, S. Kontoe, and L. Zdravkovic, A case study on the seismic performance of earth dams, Géotechnique, 65(11) (2015) 923-935.  
[10] L. Pelecanos, S. Kontoe, and L. Zdravković, The Effects of Dam-Reservoir Interaction on the Nonlinear Seismic Response of Earth Dams, Journal of Earthquake Engineering, 2018.
[11] A. Zeroual, A. Fourar, and M. Djeddou, Predictive modeling of static and seismic stability of small homogeneous earth dams using artificial neural network, Arabian Journal of Geosciences, 12(16) (2019).
[12] Y. Sawada, H. Nakazawa, W. Andy Take, T. Kawabata, Effect of installation geometry on dynamic stability of small earth dams retrofitted with a geosynthetic clay liner, Soils Found, 59 (2019) 1830-1844.
[13] Y. Sawada, H. Nakazawa, T. Oda, S. Kobayashi, S. Shibuya, T. Kawabata, Seismic performance of small earth dams with sloping core zones and geosynthetic clay liners using full-scale shaking table tests, Soils Found, 58(3) (2018) 519-533.
[14] J.H. Hwang, C.P. Wu, S.C. Wang, Seismic record analysis of the Liyutan earth dam, Can Geotech J, 44 (2007) 1351-1377.
[15] K. Wei, S. Chen, G. Li, & H. Han, Application of a generalised plasticity model in high earth core dam static and dynamic analysis, European Journal of Environmental and Civil Engineering, 2018 979-1012.
[16] Y. Li, W. Tang, L. Wen, & J. Wang, Study on seismic failure probability of high earth-rock dam considering dam body deformation and slope stability, European Journal of Environmental and Civil Engineering, 2020.
[17] K.I. Andrianopoulos, A.G. Papadimitriou, G.D. Bouckovalas, D.K. Karamitros, Insight into the seismic response of earth dams with an emphasis on seismic coefficient estimation, Computers and Geotechnics, 55 (2014) 195-210.
[18] M.S. Rahman, and S.K. Pal, Pore pressure response of earth dams in random seismic environment, Mechanics of Materials, 3(1) (1984) 19-34, North-Holland.
[19] S.H. Bian, B. Wu, Y.Z. Ma, & G.Y. Li, Development of an interface model based on hyperbolic hardening rule and contact effect analysis of earth rockfill dam, European Journal of Environmental and Civil Engineering, 2020.
[20] R.B.J. Brinkgreve, W.M. Swolfs, E. Engin, PLAXIS 2D reference manual, Delft University of Technology and PLAXIS BV, Netherlands, 2011.
[21] Ab Niroo, Consulting Engineers Company, Soleimshah dam’s foundation and body design 917 report, final modified report, 2001.
[22] H. Sharafi, Y. Shams Maleki, Evaluation of the lateral displacements of a sandy slope reinforced by a row of floating piles: A numerical-experimental approach, Soil Dynamics and Earthquake Engineering, 122(2019) 148-170.
[23] R.L. Kuhlemeyer, J. Lysmer, Finite element method accuracy for wave propagation problems, J Soil Mech Found Div, 99(SM5) (1973) 421-7.
[24] R.B.J. Brinkgreve, M.H. Kappert, and P.G. Bonnier, Hysteretic damping in a small-strain stiffness model, Proc. NUMOG X., (2007) 737-742.
[25] J.A. Santos, A.G. Correia, Reference threshold shear strain of soil. Its application to obtain a unique strain-dependent shear modulus curve for soil, In Proceedings 15th International Conference on Soil Mechanics and Geotechnical Engineering. Istanbul, Turkey, volume 1 (2001) 267-270.
[26] K. Ishihara, Soil behavior in earthquake geotechnics, Clarendon Press, Oxford, 2005.
[27] J.P. Wolf, Dynamic soil-structure interaction, Prentice-Hall, New Jersey, 1985.
[28] S.L. Kramer, Geotechnical earthquake engineering. Prentice-Hall: New Jersey, 1996.
[29] PEER, Strong ground motion database, NGA-West2, 2021, http://peer.berkeley.edu.