Optimal Dimensions of Small Hydraulic Structure Cutoffs Using Coupled Genetic Algorithm and ANN Model
Main Article Content
Abstract
A genetic algorithm model coupled with artificial neural network model was developed to find the optimal values of upstream, downstream cutoff lengths, length of floor and length of downstream protection required for a hydraulic structure. These were obtained for a given maximum difference head, depth of impervious layer and degree of anisotropy. The objective function to be minimized was the cost function with relative cost coefficients for the different dimensions obtained. Constraints used were those that satisfy a factor of safety of 2 against uplift pressure failure and 3 against piping failure.
Different cases reaching 1200 were modeled and analyzed using geo-studio modeling, with different values of input variables. The soil was considered homogeneous anisotropic. For each case, the length of protection (L) and the volume of the superstructure (V) required to satisfy the factors of safety mentioned above were calculated. These data were used to obtain an artificial neural network model for estimating (L) and (V) for a given length of upstream cutoff (S1), length of downstream cutoff (S2), head difference (H), length of floor (B), depth of impervious layer (D) and degree of anisotropy (kx/ky).
A MatLAB code was written to perform a genetic algorithm optimization modeling using the obtained ANN model .The obtained optimum solution for some selected cases were compared with the Geo-studio modeling to find the length of protection required in the downstream side and volume required for superstructure. Values estimated were found comparable to the obtained values from the Genetic Algorithm model.
Article Details
How to Cite
Publication Dates
References
Al-Duri, R. M. S. A., Feb., 1986,”Protection of Hydraulic Structures Downstream”, M.Sc. Thesis, department of Water Resources Engineering, University of Technology, Baghdad.
Al-Fatlawy, R. A. K., May, 2007,”Effect of Degree of Anisotropy on Exit Gradient under Dams using the Finite Element Method”, M.Sc. Thesis, Department of Civil Engineering, University of Kufa, Iraq.
Al-Suhaili, R. H. S., Kharrufa, N. S and Al-Oubaidy A. S, 1988,”Exit Gradient Variation Downstream of Hydraulic Structures”, Scientific Journal Published by the University of Technology, Vol.5, No. 3.
Al-Suhaili, R. H. S., 2009, ”Analytical Solution for Exit Gradient Variation Downstream of Inclined Sheet Pile”, The 6th Engineering Conference of Engineering College, College of Engineering, University of Baghdad, Iraq.
Ghobadian R. and Khodaei K., 2009, ” Effect of Cutoff Wall and Drain on Uplift Pressure and Exit Gradient under Hydraulic Structure by Numerical Solution of General Equation of Fluid Flow in Soil using Finite Volume Method”, Journal of Water and soil, Volume 23, No.4, Winter 2009, p. 148-160.
Gole A. and Pillai N. N., 2010, ”Variation of Exit Gradient Downstream of Weirs on Permeable Foundations”, The pacific Journal of Science and Technology, Volume 11, No. 1, p. 28-36.
Griffiths D. V. and Fenton G. A.,1993, ”Seepage Beneath Water Retaining Structures Founded on Spatially random Soil”, Geotechnique Volume 43, Issue 4, p. 577-587, Department of Engineering Mathematics, University of Dalhousie, Canada.
Griffiths D. V. and Fenton G. A.,1998, ”Probabilistic Analysis of Exit Gradients Due to Steady Seepage”, Journal of Geotechnical and Geo-Environmental Engineering, Volume 124, No. 9, p. 789-797, Department of Engineering Mathematics, University of Dalhousie, Canada.
Haszpra O., Kalina E. and Hamvas F., 2000, ”Seepage Around Structures Built Into Flood Levees”, Periodical Polytechnics Search Civil Engineer, Volume 45, No. 1, p. 141-149, Budapest University of Technology and Economics, Budapest, Hungary.
Ilyinsky N. B. and Kacimov A. R., 1992, ”Analytical Estimation of Ground-Water Flow Around Cutoff Walls and Into Interceptor Trenches”, Journal of Ground Water, University of Kazan, Institute of Mathematics and Mechanics, volume 30, No. 6, p. 901-907.
Ismail Sh. S. and Aziz M., 2005,”Toshka Spillway Barrages Stability Analysis”, Ninth International Water Technology Conference, (IWTC 9 2005), Sharm El-Sheikh, Egypt, p. 527-540.
Number 2 Volume 20 February 2014 Journal of Engineering
Khassaf S. I., Al-Adili A. Sh. and Rasheed R. S., 2009, ”Seepage Analysis Underneath Diyala Foundation”, Thirteenth International Water Technology conference, IWTC 13 2009, Hurghada, Egypt.
Manna M. C., Bhattacharya A. K. and Choudhury S., 2003, ”GroundWater Flow Beneath a Sheetpile Analyzed Using Six-Noded Traiangular Finite Elements” IE (I) Journal – CV, Volume 84, August 2003, p. 121-129.
Moellmann A., Vermeer P. A. and Huber M., 2008, ”A Probabilistic Finite Element Analysis of Embankment Stability Under Transient Seepage Conditions”, Sixth International Probabilistic Workshop, Darmstadt 2008, Institute of Geotechnical Engineering, University of Stuttgart, German, p. 551-562.
Mukhopadhyay S., 2008, ”Seepage Analysis Through Foundation Using Finite Element Method and Flow Net”, The 12th International Conference of International Association for computer Methods and Advances in Geo-mechanics (IACMAG), 1-6 October,2008,Goa, India.
Shadravan B., Mirghasemi A. A. and Pakzad M, 2004, ”Karkheh Storage Dam Cutoff Wall Analysis and Design”, Proceedings of Fifth International Conference on Case Histories in Geotechnical Engineering, New York, NY, April 13-17, 2004, p. 133-141.