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    Numerical study of the effects of drainage systems on saturated/unsaturated seepage and stability of tailings dams

    , Article Mine Water and the Environment ; Volume 36, Issue 3 , 2017 , Pages 341-355 ; 10259112 (ISSN) Pak, A ; Nabipour, M ; Sharif University of Technology
    Abstract
    The stability of tailings dams is affected by seepage characteristics such as the location of the phreatic surface inside the dam, the effects of the capillary fringe, and the unsaturated zone above the zero pore pressure level. In this study, the performance of drainage systems in tailings dams was investigated by analyzing saturated and unsaturated seepage in the dam, considering the effects of the construction method, tailings properties, and the type of drainage systems. First, general seepage characteristics in tailings dams were studied and the effects of non-homogeneity were investigated. Our results show that in a silty tailings dam with a height of 15 m, unsaturated plus capillary... 

    In-situ nitrate remediation using nano iron/nickel particles

    , Article Environment Protection Engineering ; Vol. 40, issue. 3 , 2014 , p. 75-86 Fadaei Tehrani, M. R ; Vossoughi, M ; Shamsai, A ; Sharif University of Technology
    Abstract
    Originally, the application of nano zero valent iron/nickel (nZVI/Ni) particles for nitrate removal in porous media was studied. nZVI/Ni was prepared and employed in batch and continuous modes. Based on batch experiments, the reaction kinetics was consistent with the adsorption model by the order of 1-1.5. The variation of the kinetics order depends on pH and nickel content. So that highest reactivity was observed for nZVI with 10% of Ni at pH ≤ 3. Nitrate remediation in a continuous system was mostly influenced by seepage velocity, quantity and freshness of nZVI/Ni and particle size of porous media. In a batch mode, the maximum nitrate removal was 99% while in a continuous mode it did not... 

    A moving-mesh finite-volume method to solve free-surface seepage problem in arbitrary geometries

    , Article International Journal for Numerical and Analytical Methods in Geomechanics ; Volume 31, Issue 14 , 2007 , Pages 1609-1629 ; 03639061 (ISSN) Darbandi, M ; Torabi, S. O ; Saadat, M ; Daghighi, Y ; Jarrahbashi, D ; Sharif University of Technology
    2007
    Abstract
    The main objective of this work is to develop a novel moving-mesh finite-volume method capable of solving the seepage problem in domains with arbitrary geometries. One major difficulty in analysing the seepage problem is the position of phreatic boundary which is unknown at the beginning of solution. In the current algorithm, we first choose an arbitrary solution domain with a hypothetical phreatic boundary and distribute the finite volumes therein. Then, we derive the conservative statement on a curvilinear co-ordinate system for each cell and implement the known boundary conditions all over the solution domain. Defining a consistency factor, the inconsistency between the hypothesis... 

    Seepage investigation of embankment dams using numerical modelling of temperature field

    , Article Indian Journal of Science and Technology ; Volume 6, Issue 8 , 2013 , Pages 5078-5082 ; 09746846 (ISSN) Yousefi, S ; Noorzad, A ; Ghaemian, M ; Kharaghani, S ; Sharif University of Technology
    2013
    Abstract
    Leakage in embankment dam by applying seepage and thermal numerical simulations are studied in this paper. Unpredicted seepage in earthen dams is known as the main cause of damage in most cases. Determination of seepage flow quantity and prediction of dam leakage is very important. Temperature variation in dam body can be simulated to estimate the water velocity in soil layers. While moving through dam body, seepage flow carries all physical specifications of reservoir water, including its temperature. Mass and energy balance equations are discretized for modeling flow and temperature fields. The finite element method along with a mathematical model has been utilized to discretize and solve... 

    Seepage through rockfill dams in narrow valleys

    , Article Proceedings of From Research to Practice in Geotechnical Engineering Congress 2008 - From Research to Practice in Geotechnical Engineering, 9 March 2008 through 12 March 2008, New Orleans, LA ; Volume 325 , 2008 , Pages 522-539 ; 9780784409626 (ISBN) Soleimanbeigi, A ; Jafarzadeh, F ; Sharif University of Technology
    2008
    Abstract
    Seepage analysis serves as one of the most significant stages in the design process of an embankment dam. In two-dimensional (2D) seepage analysis of embankment dams, little or no attention is paid to the seepage through side abutments. Moreover the role of grout curtain extensions into the side abutments and abutment material properties are inevitably neglected when performing a 2D seepage analysis. In this paper, two and three-dimensional (3D) models of a rockfill dam during operation state are generated and several unsteady and steady state seepage analyses are performed using finite element method (FEM). The results obtained from 2D and 3D seepage analyses were compared with measurements... 

    Survey the Change of Phreatic Line Position in the First Filling of Earth Dams until Steady State Seepage

    , M.Sc. Thesis Sharif University of Technology Razi, Arezoo (Author) ; Jafarzadeh, Fardin (Supervisor)
    Abstract
    Since seepage-related problems account for the cause of more than forty percent of dam failure seepage analysis serves as one of the most significant stage in the design process of an embankment dam. Currently a steady seepage analysis in a typical or maximum cross section of the dam is formed instead of transient seepage analysis for simplicity. In this way, for the change of condition (unsaturated to saturated) in the first filling of dams and it’s effects on behavior and reaction of dams until the steady seepage condition established; the results of steady seepage analysis cannot be satisfactory. In this thesis, based on finite element method and with assumption of saturated-unsaturated... 

    Verification of Two and Three Dimensional Seepage Analyses Results’ Correctness in Embankment Dams According to Instrumenting Data (Case Study: ZAGROS, SHIAN & HAALEH Dams)

    , M.Sc. Thesis Sharif University of Technology Yarahmadi, Nazanin (Author) ; Jafarzadeh, Fardin (Supervisor)
    Abstract
    Since, seepage- related problems account for more than forty percents of earth dams’ failure, seepage analysis is one of the most important stages in designing of embankment dams. The most usual method of making a seepage analysis is doing a two dimensional one in the maximum cross- section and generalizing its results to the third dimension. As a natural consequence of this kind of seepage analysis, the effect of valley shape and material properties’ changes along the third dimension are ignored and so, in narrow valleys where the cross-section changes along longitude profile or in the specific cases of nonhomogeneity, using this kind of analysis can make false results. Besides, because of... 

    Analysis Of Tunneling - upper Structure Interaction in The State of Underground Water Drainage During Excavation Using Three-Dimensional Numerical Modeling

    , M.Sc. Thesis Sharif University of Technology Azizabadi Farahani, Mohsen (Author) ; Sedghiani, Mohammad Hossein (Supervisor)
    Abstract
    Excavation of tunnel beneath groundwater level, and drainage of water from the sides of the tunnel, causes disturbance of hydrogeological balance and change in the stress and pore water pressure distribution, which causes ground subsidence. Various parameters effect on stress distribution and surface settlement caused by tunneling. In this thesis, Effects of soil geotechnical properties such as the angle of internal friction, cohesion, modulus of elasticity, permeability and tunnel parameters such as depth, depth of groundwater level, the tunnel advance rate, structure weight, foundation eccentricity relative to the axis of the tunnel and foundation dimensions are evaluated. To do this with... 

    Evaluation of seepage problem under a concrete dam with finite volume method

    , Article Proceedings of the 7th IASME / WSEAS International Conference on Fluid Mechanics and Aerodynamics, FMA '09, 20 August 2009 through 22 August 2009 ; 2009 , Pages 34-40 ; 9789604741069 (ISBN) Shamsai, A ; Abdi Dezfuli, E ; Zebardast, A ; Sharif University of Technology
    Abstract
    In most of countries, underground waters are the most important sources to provide drinking water. So it is necessary to make scheme and to do high protection of to achieve maximum beneficiary. Necessity of this management is going to be felt by developing these sources and human's interference. However, in the past overtopping phenomenon was the first reason of dam's destruction, but nowadays by increasing of spate design's period, the significant problem that researchers are interfere with, is seepage problem. The purpose of solving the underground problems is to procure height of water as a function of coordinate and time. In observation of practical industries, we can use the... 

    Transient free-surface seepage in three-dimensional general anisotropic media by BEM

    , Article Engineering Analysis with Boundary Elements ; Vol. 46, issue , 2014 , p. 51-66 Rafiezadeh, K ; Ataie-Ashtiani, B ; Sharif University of Technology
    Abstract
    Kinematic boundary condition is usually used when dealing with transient free-surface flow problems in isotropic media. When dealing with anisotropic problems, a transformation can transform the anisotropic media to an equivalent isotropic media for seepage analysis, but the kinematic boundary condition cannot be used directly in the transformed media. A generalization of the kinematic boundary condition along any arbitrary direction is derived for use in the transformed domain for general three-dimensional anisotropic problems. A boundary element method for solving transient free-surface seepage problems is developed and the treatment of the proposed kinematic boundary condition in the... 

    Three dimensional flow in anisotropic zoned porous media using boundary element method

    , Article Engineering Analysis with Boundary Elements ; Volume 36, Issue 5 , 2012 , Pages 812-824 ; 09557997 (ISSN) Rafiezadeh, K ; Ataie Ashtiani, B ; Sharif University of Technology
    2012
    Abstract
    Coupling the adjacent zones for seepage analysis in porous media needs compatibility and equilibrium equations (equality of potential on coinciding nodes and conservation of flowing mass between zones, respectively). When stretched coordinate transformation is applied to the anisotropic zones, the Dirichlet boundary conditions remain unchanged, but the Neumann boundary condition should also be transformed. Similarly in a zoned problem, for the interface between zones, compatibility equations remain unchanged during the transformation while the equilibrium equations should be transformed. In this paper, transformed Neumann boundary conditions and equilibrium equations for the interface of... 

    Seepage analysis in multi-domain general anisotropic media by three-dimensional boundary elements

    , Article Engineering Analysis with Boundary Elements ; Volume 37, Issue 3 , 2013 , Pages 527-541 ; 09557997 (ISSN) Rafiezadeh, K ; Ataie Ashtiani, B ; Sharif University of Technology
    2013
    Abstract
    A three-dimensio111nal boundary element solution for the seepage analysis in multi-domain general anisotropic media has been developed based on the transformation approach. Using analytical eigenvalues and eigenvectors of the hydraulic conductivity tensor, a closed-form coordinate transformation matrix has been provided to transform the quadratic form of governing equation of seepage for the general anisotropic media to the Laplace equation. This transformation allows the analysis to be carried out using any standard BEM codes for the potential theory on the transformed space by adding small pre- and post-processing routines. With this transformation, any physical quantity like the total... 

    3-D Analysis of Effects of Groundwater and Mechanical Properties of Soil on Settlement of Metro Tunnels

    , M.Sc. Thesis Sharif University of Technology Bagheri Asl, Shoja (Author) ; Sedghiani, Mohammad Hossein (Supervisor)
    Abstract
    Excavation of metro tunnel beneath groundwater level causes disturbance of hydro geological balance and change in stress conditions at its environment. One of the usual methods of the tunnel construction is utilizing tunnel boring machine and one of the most important of them is called TBM-EPB which takes advantage of the earth pressure balance method. Control of surface settlements which is a result of creating underground space in urban area is a matter of great importance and is influenced by various parameters. This thesis has tried to investigate factors such as geotechnical properties among cohesion, internal friction angle, elasticity modulus, permeability and porosity and also...