مطالعه و بررسی عددی سدهای خاکی بعد ساخت و اولین آبگیری (مطالعه موردی: سد خاکی دویرج)

نوع مقاله : یادداشت پژوهشی

نویسندگان

دانشکده فنی و مهندسی، دانشگاه آیت‌الله العظمی بروجردی(ره)

چکیده

کنترل ایمنی و پایداری سدهای خاکی در دوران ساخت، انتهای ساخت، اولین آبگیری و بهره‌برداری آن بسیار حائز اهمیت است. ارزیابی مقایسه‌ای نتایج تجزیه‌وتحلیل‌ها برای ایمنی ساختار و همچنین عملیات نگهداری منظم ضروری است. علاوه براین واضح است که مطالعات دقیق مبتنی بر چنین مقایسه‌هایی بـرای به­ دست آوردن تجربه برای طرح‌های آینده مفید خواهد بود. در این مطالعه سد خاکی دویرج از نظر پارامترهای فیزیکی مانند، جابه‌جایی‌ها، تغییر شکل‌ها، تنش‌ها، فشار آب منفذی و پایداری آن در پایان ساخت و اولین آبگیری موردبررسی مقایسه‌ای قرار گرفت. مدل‌سازی عددی با استفاده از دو نرم‌افزار FLAC 2D و GEO STUDIO با مدل رفتاری موهر- کلمب (Mohr–Coulomb) انجام شد. نتایج بررسی‌ها نشان داد بیشترین نشست عمودی در تاج هسته رسی بعد از اولین آبگیری با مقدار 70 سانتی‌متر و همچنین بیشترین مقدار جابه ­جایی افقی در پایین‌دست سد برابر 12 سانتی‌متر رخ‌ داده است. در بررسی تنش‌ها نیز مشخص شد که مقدار بیشینه‌ تنش‌های حاصل در مقطع هسته حدود 1000 کیلو پاسکال به‌دست‌آمده است.

کلیدواژه‌ها


عنوان مقاله [English]

Numerical Study of Earthdams after Construction and First Impounding (Case Study of Doyraj EarthDam)

نویسندگان [English]

  • Ahmadreza Mazaheri
  • Mehdi Komasi
  • Majid Veisi
Department of Civil Engineering, Engineering Faculty, Ayatollah Borujerdi University
چکیده [English]

Engineering and economic investigations in dam construction projects throughout the world indicate that, in many cases, rockfill dams with impervious clay cores are the best selection for the final design (Rezaei and Salehi, 2011). This approach makes the investigation of different issues affecting the stability of rockfill dams worthwhile. In general, dam safety is the first and foremost reason for controlling deformation and physical parameters in dams. Another reason is the importance of basic design concepts for engineers to apply in future designs as well as understanding the resistive and behavioral characteristics of soil and pebbles. One of the most effective approaches for interpreting the mechanical and hydraulic behavior of structures such as dams is to use data and compare the results with numerical modeling predictions. In the field of earth and rockfill dams, monitoring of typical physico-mechanical behaviors is a fundamental issue. Measurements of displacements, total stresses, pore water pressures, and arching ratio can be used to carry out a number of tasks (ICOLD, 1982), such as characterizing the dam’s overall behavior (Pagano et al., 1998), checking the behavior of specific zones, obtaining information about the in situ mechanical properties of embankment soils (Marsal and Resendiz, 1975), and finally, supporting the difficult task of evaluating dam safety and efficiency (Gould and Lacy, 1993). Justo (1991) and Naylor (1997) proposed methods for the incorporation of collapse settlement of rockfill into constitutive models. Naylor (1991) performed the finite element analysis for Beliche dam, a central core earth and rockfill dam, by considering the collapse settlement of the upstream rockfill in the modeling. The effect of pore water pressure dissipation in earthfill during construction was also considered by a number of authors including Eisenstein and Law (1977) and Cavounidis and Hoeg (1977), amongst others. For these cases, the incremental embankment construction was modeled as a two-stage process, the first stage modeling the new layer construction using undrained properties for the core and the second stage modeling pore water pressure dissipation. Zomorodian and Kuchi studied internal deformation, pore water pressure, and total vertical stresses in Masjed Soleiman Dam and compared it to numerical results, they also showed that the development of excess pore water pressure in the clay core of zoned earth dams during construction may lead to the onset or progression of hydraulic failure.

کلیدواژه‌ها [English]

  • Numerical Analysis
  • Earth-Rockfill dam
  • Instrument results
  • Geo-Studio
  • FLAC
Bo Han, Lidija Zdravkovic, Stavroula Kontoe, David M.G. Taborda, “Numerical investigation of ther esponse of theYele rockfill dam during the 2008 Wenchuan earthquake”, Soil Dynamics and Earthquake Engineering, 2016, 88, 124-142.
Eisenstein Z, Law STC, “Analysis of consolidation behavior of Mica dam”, Journal of the Geotechnical Engineering Division, ASCE, 1977, 103 (GT8), 879-95.
Eberhardt E, “Rock slope stability analysis-utilization of advanced numerical techniques”, Departement of Earth and Ocean Sciences at UBC Report, University of British Columbia (UBC), Vancouver, Canada, 41.
Gould JP, Lacy HS, “Seepage control in dam rehabilitation. In: Proceedings of the Geotechnical Practice in Dam Rehabilitation”, ASCE, 1993, 240-55.
GeoSlope International Ltd, “SEEP/W Users Guide”, GeoSlope International, Calgary, Canada, 2007.
Huang YH, “Stability Analysis of Earth Slopes”, Van Nostrand Reihold Co, 1983, New York.
ICOLD, “Lessons from dam incidents”, In: International commission of large dams, Abridged ed, MA (USA): 1973, USCOLD.
ICOLD, “Monitoring of dams and their foundations - state of the art”, Bulletin, 1989, 681-327.
Rashidi A, Mohsen Haeri B, “Evaluation of behaviors of earth and rockfill dams during construction and initial impounding using instrumentation data and numerical modeling”, Journal of Rock Mechanics and Geotechnical Engineering”, 2017, 9, 709-725.
Rashidi M, Heidar M, Azizyan G, “Numerical analysis and monitoring of an embankment dam during construction and first impounding (case study: Siah Sang Dam)”, Scientia Iranica, 2018, 25 (2), 505-516.
Mortazavi Zanjani A, Soroushn M, Khoshini M, “Two-dimensional numerical modeling of fault rupture propagation through earth dams under steady state seepage”, Soil Dynamics and Earthquake Engineering, 2016, 88, 60-71.
Marsal RJ, Resendiz D, “Earth dams and rockfill”, Mexico City, Mexico: Limusa, 1975 (in Spanish).
Rashidi M, Rasouli H, “Initial Hypotheses for Modeling and Numerical Analysis of Rockfill and Earth Dams and Their Effects on the Results of the Analysis”, Advances in Civil Engineering, 2018, Article ID 3974675, 7 pages.
Naylor DJ, “Collapse settlement e some developments”, In: Applications of Computational Mechanics in Geotechnical Engineering, Rotterdam: A. A. Balkema, 1997, 37-54.
Ormann L, Zardari MA, Mattsson H, Bjelkevik A, Knutsson S, “Numerical analysis of strengthening by rockfill embankments on an upstream tailings dam”, Canadian Geotechnical Journal, 2013, (50), 391-9.
Pagano L, Desideri A, Vinale F, “Interpreting the settlement profiles of earth dams”, Journal of Geotechnical and Geoenvironmental Engineering, 1998, 124 (10), 923-932.
Si-hong Liu Liu-jiang Wang, Zi-jian Wang, Erich Bauer, “Numerical stress-deformation analysis of a cut-off wall in clay-core rockfill dam on thick overburden”, Water Science and Engineering.
Sowers G, Sally H, “Earth and rockfill dam engineering”, London (UK), 1989, Asia Publishing House.
U.S. Army crops of Engineers, “Stability of Earth and Rock-Fill Dams”, U.S. Department of my, Crops of Engs, 1970, EM 110-2-1902.
Zhou W, Hua J, Chang X, Zhou C, “Settlement analysis of the Shuibuya concrete-face rockfill dam”, Computers and Geotechnics, 2011, 38 (2), 269-80.
Zomorodian SMA, Chochi H, “Numerical Analysis of Earth-Rockfill Dams Behavior During Construction and First Stage Impounding”, Water Engineering Department, Shiraz University, 2014 Shiraz, Iran.