بررسی خصوصیات ژئوتکنیکی رسوبات ته‌‌نشین‌شده در مخزن سد لتیان با استفاده از اندازه‌گیری میدانی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد مهندسی ژئوتکنیک و آب، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی، لویزان، تهران، ایران

2 استادیار، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی،تهران

3 دانشیار گروه مهندسی ژئوتکنیک و آب، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی، لویزان، تهران

4 استادیار گروه مهندسی ژئوتکنیک، دانشکده فنی، دانشگاه گیلان، رشت، ایران

چکیده

هدف از این تحقیق بررسی و تحلیل نتایج حاصل از آزمایشات فیزیکی بر روی نمونه­های رسوب برداشت شده از مخزن سد لتیان در استان تهران می­باشد. پس از انجام عملیات پیمایش و بازدید از مخزن سد لتیان، 8 نقطه مهم جهت برداشت نمونه سطحی تعیین شد و بر روی این رسوبات آزمایش­های متداول مکانیک خاک شامل دانه­بندی، وزن مخصوص و سه محوری جهت تعیین پارامترهای مقاومتی خاک و تحکیم انجام شد. نتایج تحقیق حاضر نشان داد که با نزدیک شدن از لبه­های مخزن سد به سمت دیواره سد، درصد رطوبت خاک به میزان بیش از 2 برابر افزایش می­یابد. علت این موضوع ریزدانه­تر شدن اندازه دانه­های خاک است بطوریکه درصد رس و لای موجود در نزدیکی محور سد، بیش از 89 درصد بوده است. با توجه به نتایج آزمایش تراکم و با استفاده از معادلات تجربی مشخص شد که بعد از گذشت 100 سال از ته­­نشست رسوبات در مخزن سد لتیان، جرم مخصوص ظاهری خشک رسوبات برابر با 128/1گرم بر سانتیمتر مکعب خواهد شد. همچنین، با توجه به نتایج آزمایشات سه محوری مشخص شد که مقادیر چسبندگی و زاویه اصطکاک داخلی در نهشته­های مخزن(خاک) سد لتیان به ترتیب برابر با مقادیر 51/0 کیلوگرم بر سانتی­مترمربع و °1/26 می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Study on Geotechnical Properties of Sediment Deposited in Latian Dam Reservoir Using Field Measurements

نویسندگان [English]

  • Omid Asiaei 1
  • Mojtaba Karimaei Tabarestani 2
  • Abolfazl Soltani 3
  • Meghdad Payan 4
1 Msc Graduated, Civil Engineering Department, Shahid Rajaei Teacher Trainig University, Lavizan, Tehran, Iran
2 Assistant Professor, Civil Eng. Department, Shahid Rajaee Teacher Training University, Tehran, Iran
3 Associate proffesor, Civil Engineering Department, Shahid Rajaei Teacher Trainig University, Lavizan, Tehran, Iran
4 Asisstant proffesor, Engineering Department, Gillan University, Rasht, Iran
چکیده [English]

This study aims to investigate and analyze the results of geotechnical experiments on sediment samples taken from the Latian Dam reservoir in Tehran province. After the site visit, eight important stations were identified for surface sediment sampling, and on these sediments, common soil mechanics tests such as grain size analysis, determination of specific gravity, consolidation, compaction, and triaxial were performed to determine soil resistance and consolidation parameters. The present study results showed that by approaching the dam wall, soil water content increased by more than two times. This is due to the smaller size of the soil grains so that the percentage of clay and silt near the dam wall was more than 89%. According to the compaction test results and empirical equations, it was found that after 100 years of sediment deposition in the Latian dam reservoir, the dry density of the sediment will be equal to 1.128 g/cm3. In addition, from the triaxial test results, it was found that the cohesion and internal friction angle parameters of the sediments were equal to 0.51 kg/cm2 and 26.1°, respectively.

کلیدواژه‌ها [English]

  • Latian dam
  • Reservoir Sedimentation
  • geotechnical properties
  • Triaxial Test
  • Compaction Test
Basson, G.R. (2009). Management of siltation in existing and new reservoirs. General Report Q. 89. Proc. of the 23rd Congress of the Int. Commission on Large Dams CIGBICOLD (vol. 2).
Bayat M., Qaderi K. And Ahmadi M. (2016). Uncertainty analysis of reservoir sedimentation using fuzzy α-cut (Case study: Latian Dam). Journal of Dam and Hydropower Plant. 3(10), 1 - 11.
175 / 5000
Behrangi, F., Bani Hashemi, M., Pourbojarian, A. And Rahmanian, M. (2008). Investigation of sedimentation process in Latian dam reservoir using hydrographic results. 7th Iranian Hydraulic Conference, Tehran. (In Farsi)
Bronstert, A., de Araújo, J.-C., Batalla, R. J., Costa, A. C., Delgado, J. M., Francke, T. and Vericat, D. (2014). Process based modelling of erosion, sediment transport and reservoir siltation in mesoscale semi-arid catchments. Journal of Soils and Sediments. 14(12), 2001–2018.
De Cesare, G., and Lafitte, R. (2007). Outline of the historical development regarding reservoir sedimentation. 32nd IAHR Congress, Venice.
Habibi S., Gholami H. And Fathabadi A. (2018). Source fingerprinting of sediment deposited in the dam reservoir: a case of Lavar dam watershed, Fin, Hormozgan province. Environmental Erosion Research. 8: 3 (31), 1-15.
Imran, J., Parker, G., Locat, J., and Lee, H. (2001). 1D numerical model of muddy subaqueous and subaerial debris flows. Journal of Hydraulic Engineering. 127(11), 959–968.
Juracek, K.E. (2015). The aging of America’s reservoirs: Inreservoir and downstream physical changes and habitat implications. JAWRA Journal of the American Water Resources Association. 51(1), 168–184.
Khastar M., Samadi Boroujeni H., Fattahi R., Ghasemi M., Naghshbandi A. And Heydari M. (2019). Laboratory study of the sedimentation process of suspended sediments in the reservoir of Karkheh Dam. Amirkabir Civil engineering Journal. 51 (2), 327-339. (In Farsi)
Lai, S.Y., and Capart, H. (2009). Reservoir infill by hyperpycnal deltas over bedrock. Geophysical Research Letters, 36(8).
Lane, E.W., and Koelzer, V.A., (1943). Density of Sediments Deposited in Reservoirs. Report No. 9. In A Study of Methods Used in Measurement and Analysis of Sediment Loads in Streams. Hydraulic Lab, U of Iowa.
Lara, J.M., and Pemberton, E.L., (1963). Initial Unit Weight of Deposited Sediments. pp. 818-845. Proc. Federal Interagency Sedimentation Conf., USDA-ARS Misc. Publ. 970.
Management and Planning Organization (2006). Field Operations Guide for Sample Rivers and Reservoirs. Code No. 349, Ministry of Energy. (In Farsi)
Miller, C.R., (1953). Determination of the Unit Weight of Sediment for Use in Sediment Volume Computations. U.S. Bureau of Reclamation, Denver.
Ministry of Power. (2011). Guide to sedimentation and descaling studies of dam reservoirs. Office of Engineering and Technical Standards of Water and ABFA. Technical Guide No. 589.
Mulder, T., and Alexander, J. (2001). The physical character of subaqueous sedimentary density flows and their deposits. Sedimentology. 48(2), 269–299.
Morris, G.L. and Fan, J. (1998). Reservoir sedimentation handbook. New York: McGraw-Hill.
Morgan, R. (2009). Soil erosion and conservation. Oxford: John Wiley.
Müller, M., De Cesare, G., and Schleiss, A.J. (2014). Continuous long-term observation of suspended sediment transport between two pumped-storage reservoirs. Journal of Hydraulic Engineering. 140(5), 05014003.
Randle, T.J. and Bountry, J.A. (2017). Sediment analysis guidelines for dam removal. U.S. Department of the Interior, Bureau of Reclamation for the Federal Advisory Committee on Water Information, Subcommittee on Sedimentation, Denver, CO.
Samadi, H., Fathi Moghadam, M. and Zolfi, A. (2012). Survey physical properties of the always submerged sediments in Dez dam reservoir using the field data and the empirical methods application. Irrigation Science and Engineering. 36 (1) 57-62. (In Farsi)
Samadi, H., Shafaei Bajestan, M. And Fathi Moghaddam, M. (2007). Study on sedimentation process and consolidation of cohesive sediment of Dez dam reservoir. Agricultural Science and Technology and Natural Resources. 40 (a), 1-11. (In Farsi)
Schleiss, A.J., and De Cesare, G. (2010). “Physical model experiments on reservoir sedimentation”, IAHR Hyrolink, 4, 54–57.
Simpson, J. E. (1999). “Gravity currents: In the environment and the laboratory”, Cambridge: Cambridge University Press.
Sumi, T., and Hirose, T. (2009). “Accumulation of sediment in reservoirs”, Water storage, transport and distribution (pp. 224–252). Paris, France: UNESCO-IHE and EOLSS Publishers Co. Ltd.
Sundborg, A. (1992). “Lake and reservoir sedimentation prediction and interpretation”, Geografiska Annaler. Series A. Physical Geography, pp. 93–100.
Yasarer, L.M., and Sturm, B.S. (2016). Potential impacts of climate change on reservoir services and management approaches. Lake and Reservoir Management. 32(1), 13–26.
United States Department of Agriculture (USDA), Soil Conservation Service (1985). National Engineering Handbook, Section 3 Sedimentation, Chapter 8, Sediment-Storage Design Criteria.