Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X55220230421Optimization of the Clay Core of Earth Dams with Regression MethodOptimization of the Clay Core of Earth Dams with Regression Method265278502110.22060/ceej.2022.21205.7651FAMostafaZalnejadCivil Engineering Department Kharazmi University,Tehran,IranSeyed ShahabEmamzadehCivil Engineering Department, Kharazmi University. TehranJournal Article20220311<span style="letter-spacing: .05pt;">In the optimal design for the core cross-section of an earth dam, the type of material, its dimensions, and its shape are very important. So with the least volume of materials, it has the greatest effect in reducing the amount of seepage from the dam body and maintaining its stability. The purpose of this research is to develop a model for optimizing the core geometry of Hajilerchai dam near Tabriz City based on the integration of the equations obtained from the simulation of seepage, hydraulic gradient, and stability reliability factor with the Simplex algorithm. In this study, two objective functions were considered, one is the volume of soil material per unit length of the dam and the other is the seepage rate from the dam body. Then, by defining 50 different sections of the core of the earth dam and using the results of numerical analysis of seepage regression relationships, stability coefficient and hydraulic gradient were obtained. To validate the regression relationships, the values of stability coefficient, hydraulic gradient, and seepage obtained from the optimal core model were compared with the results obtained from GeoStudio software models in three sections. This comparison showed a high correlation of about 99%. The results of the model developed to determine the optimal dimensions of the earth dam core were compared with the actual dimensions of the Hajilerchai dam which indicated a reduction in the volume of materials required for the construction of the dam core by about 12%, which also provides the necessary stability.</span><span style="letter-spacing: .05pt;">In the optimal design for the core cross-section of an earth dam, the type of material, its dimensions, and its shape are very important. So with the least volume of materials, it has the greatest effect in reducing the amount of seepage from the dam body and maintaining its stability. The purpose of this research is to develop a model for optimizing the core geometry of Hajilerchai dam near Tabriz City based on the integration of the equations obtained from the simulation of seepage, hydraulic gradient, and stability reliability factor with the Simplex algorithm. In this study, two objective functions were considered, one is the volume of soil material per unit length of the dam and the other is the seepage rate from the dam body. Then, by defining 50 different sections of the core of the earth dam and using the results of numerical analysis of seepage regression relationships, stability coefficient and hydraulic gradient were obtained. To validate the regression relationships, the values of stability coefficient, hydraulic gradient, and seepage obtained from the optimal core model were compared with the results obtained from GeoStudio software models in three sections. This comparison showed a high correlation of about 99%. The results of the model developed to determine the optimal dimensions of the earth dam core were compared with the actual dimensions of the Hajilerchai dam which indicated a reduction in the volume of materials required for the construction of the dam core by about 12%, which also provides the necessary stability.</span>https://ceej.aut.ac.ir/article_5021_6a67dac531bbb618fcfa7d3811704079.pdf