استادیار گروه مهندسی آب، دانشکده کشاورزی، دانشگاه ارومیه، ارومیه، ایران
تاریخ دریافت: 20 مهر 1392،
تاریخ بازنگری: 31 خرداد 1393،
تاریخ پذیرش: 22 مرداد 1393
چکیده
در این تحقیق اهمیت بهکارگیری توابع نفوذپذیری در تحلیل نشت دائم و غیر دائم (انتقالی) غیر محصور در محیطهای همگن و غیر همگن بررسی شد. برای این منظور حالات مختلف جریان در محیطهای همگن و غیر همگن با لحاظ خصوصیات هیدرولیکی مصالح مستخرج از بانک اطلاعاتی خاکهای غیر اشباع (UNSODA) و به کمک یک مدل کامپیوتری مبتنی بر روش اجزای محدود مطالعه شد. برای اعتبارسنجی نتایج این تحلیل، از دادههای ابزار دقیق ثبت شدهی سد حسنلو طی دوره یکساله استفاده گردید. نتایج بررسیها نشان داد که در محیط غیر همگن و سدهای ناحیهبندی شده، خصوصیات هیدرولیکی مصالح پایین دست نسبت به مصالح بالادست بر موقعیت سطح نشت مؤثرتر است. همچنین طبق یافته‌های تحقیق، موقعیت سطح نشت در شرایط بهکارگیری هدایت هیدرولیکی ثابت نسبت به هدایت هیدرولیکی متغیر در شرایط بالا آمدن سطح آب در مخزن رشد آهستهتری داشته و در عین حال در شرایط پایین افتادن سطح آب در مخزن، سرعت زهکشی مصالح بیشتر میباشد. مقایسه دادههای واقعی ثبت شده با نتایج مدل نشان می‌دهد که جهت حصول نتایج واقع بینانه لازم است خصوصیات هیدرولیکی مصالح بهصورت تابع هدایت هیدرولیکی تعریف گردد یا اینکه حداقل برای مصالح پایین دست این شرایط رعایت شود.
Investigation on the Effects of Hydraulic Conductivity Function in Unconfined Seepage Analysis (Case study: Hassanlu Earth Dam)
نویسندگان [English]
Hojat Ahmadi؛ Vahid Rezaverdinejad
Assistant Professor, Department of Water Engineering , Faculty of Agriculture, Urmia University., Urmia., Iran
چکیده [English]
In this research the emphasis of the application of hydraulic conductivity function in seepage analysis through in homogenous and nonhomogeneous medium was investigated. For this aim, different forms of flow in mentioned mediums were analyzed via a finite element numeric model based on hydraulic properties were selected from unsaturated soils database (UNSODA). In order to validate the results annual recorded data in Hassanlu earth dam was used. The results showed, in nonhomogeneous medium as well as zoned earth dams, the role of downstream material is more significant. Furthermore, the phreatic line in the state of employing constant conductivity in instead in conductivity function rises rapidly in the conditions of rising water lever at the boundaries while in drawdown it drain faster. Comparison between filed data and model results also showed to get realistic results employing of hydraulic conductivity in the form function is essential at least for downstream materials.
Arya,L.M and Paris,J.F. 1981. A physicoempirical model to predict the soil moisture characteristic for particle-size distribution and bulk density data. Soil Soil Science Society of America Journal. 45: 1023-1030.
Balaam,N. 2005. Finite element seepage analysis: FESEEP. Center for Geotechnical Research University of Sydney.
Bardet,J.P., Tobita,T. 2002 A practical method for solving free-surface seepage problems. Computers and Geotechnics. 29: 451-475.
Fredlund,D.G and Rahardjo, H. 1993. Soil mechanic for unsaturated soil. John wiley & sons Inc.
Fredlund,D.G and Xing,A. 1994. Equations for the soil-water characteristic curve. Canadian Getechnical Journal. 31 (4): 521-532.
Ghanbarian-Alavijeh,B., Liaghat.A., Huang,G.H and Van Genuchten,M.Th. 2010. Estimation of the van genuchten soil water retention properties from soil textural data. Pedosphere, 20 (4): 456-465.
Green,R.F and Corey,J.C. 1971. Calculation of hydraulic conductivity: a further evaluation of some predictive methods. Soil Sci. Soc. Am. Proceeding. 35: 3-8.
Gupta,S.C and Larson,W.E. 1979. Estimating soil water retention characteristics from particle size distribution, organic matter percent and bulk density. Water resource research. 15: 1633-1635.
Ji,Ch.N., Wang,Y.Z and Shi,Y. 2005. Application of modified EP method in steady seepage analysis. Computers and Geotechnics. 32 (1): 27-35.
Krahn,J. 2004. Seepage modeling with Seep/w: an engineering methodology. Geo-Slope International Ltd. Canada.
Leij, F.J., Alves, W.J., Van Genuchten, M.Th., and Williams, J.R. 1996. Unsaturated soil hydraulic database, UNSODA 1.0 User’s manual. EPA Report 600/R96/095. USEPA, Ada
Moriasi,D.N., Arnold,J.G., Van Liew,M.W., Harmel, R.D and Veith,T.L. 2007. Model evaluation guidelines for systematic quantification of accuracy in watershed simulation. American society of agriculture and biological engineers. 50 (3): 885-900.
Munoz,J.J., Delaure,E and De Gennaro,V. 2008. Experimental determination of unsaturated hydraulic conductivity in compacted silt. Unsaturated soils: Advances and in geo-engineering. Taylor and Francis group. London.
Sang Il,H., and Sang Il,Ch. 2006. Use of a logarithmic distribution model for estimation soil water retention curves from particle-size distribution data. Journal of Hydrology. 323: 325-334.
Srivastava,A., Sivakumar Babu,G.L and Halder,S. 2010. Influence of spatial variability of permeability on steady state seepage and slope stability analysis. Engineering Geology. 110 (3-4): 93-101.
Smettem,K.R.J and Gregory,P.J. 1996. The relation between soil water retention and particle-size distribution parameters for some predominantly sandy western Australian soils. Aust. J. Soil Research. 34 (5): 695-708.
Timlin, D.J. Pachepsky, Ya.A, Acook, B. and whisler,F. 1996. Indeirect estimation of soil hydraulic properties to predict soybean yield using GLYSIM. Agricultural system. 52 (2/3). pp. 331-353.
Van Genuchten,M.Th. 1980. A closed form equation for predicting hydraulic conductivity of unsaturated soils. Soil science society of America journal. 44: 892-898.
Van Genuchneten,F.J., Leij,F.J and Yates,S.R. 1991. The RETC code for quantifying the hydraulic functions of unsaturated soils. U.S. Salinity: Laboratory. Agricultural research service. California. USA.
Xu,Y.Q., Unami,K and Kawachi,T. 2003. Optimal hydraulic design of earth dam cross section using saturated-unsaturated seepage flow model. Advance in Water Resource. 26 (1): 1-7.
Zhang,Y.L., Chen,R and Li,J.H. 2011. Evaluation the accuracy of unsaturated hydraulic conductivity determined by instantaneous profile method. Unsaturated Soils: Theory and Practice. Proceeding. Kasetsart University, Thailand.
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