Loading...
Search for:
embankments
0.011 seconds
Total 21 records
Assessment of 2DH and pseudo-3D modelling platforms in a large saline aquatic system: Lake Urmia, Iran
, Article Hydrological Processes ; Vol. 28, Issue. 18 , 2014 , pp. 49534970 ; ISSN: 10991085 ; Tofighi, M. A ; Bakhtiari, A ; Sharif University of Technology
Abstract
The main objective of this paper is to provide comparative quantitative examinations on the capabilities of two-dimensional horizontal and pseudo-three-dimensional (3D) modelling approaches for simulating spatial and temporal variability of the flow and salinity in Lake Urmia, Iran. The water quality in the lake has been an environmentally important subject partly because this shallow hypersaline aquatic ecosystem is considered to be one of the largest natural habitats of a unique multicellular organism, Artemia urmiana. This brine shrimp is the major food source for many of the protected and rare shorebirds that visit the lake. A.urmiana can grow and survive in certain ranges of salinity,...
The hydro-mechanical behavior of infilled rock joints with fill materials in unsaturated conditions
, Article Geotechnical Special Publication ; Issue 231 , 3-7 March , 2013 , Pages 129-138 ; 08950563 (ISSN) ; 9780784412787 (ISBN) ; Khosravi, M ; Meehan, C. L ; Sharif University of Technology
2013
Abstract
The existence, nature, and frequency of discontinuities in a given rock mass typically govern the overall shear behavior of the rock. The presence of fine materials such as clay and silt within rock joints, whether the product of infilling or natural weathering processes, can have a significant effect on the shear behavior of the rock joint. When assessing the strength of filled rock joints, it is therefore necessary to determine the separate strengths of both the rock and the joint infill material, and to also have a good understanding of the interaction between the two for various joint geometries and levels of infilling. Much of the existing research on the shear strength of filled rock...
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) ; 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...
Evaluation of the geo-mechanical parameters of the interface between asphalt concrete and sand with applying direct shear test and numerical modeling
, Article Advanced Materials Research ; Volume 587 , 2012 , Pages 116-121 ; 10226680 (ISSN) ; 9783037855133 (ISBN) ; Rostami, A ; Karimi, M. M ; Taherkhani, H
2012
Abstract
Asphaltic concrete has been used as waterproofing core in embankment dams, since 1948. In this application, the asphaltic core is surrounded by granular filter materials. The interaction of the asphaltic concrete and the granular materials has not been sufficiently investigated. In this paper the mechanical behavior of the interface between a natural smooth sand filter and asphaltic concrete at different levels of normal stresses and a constant shear strain rate has been studied. Small scale direct shear test has been conducted in this study, in which the shear surface is considered as the interface. Asphalt concrete specimens used in the shear test were cut in square shape (10×10×2.5 cm)...
Effect of specimen's age on mechanical properties of plastic concrete walls in dam foundations
, Article Electronic Journal of Geotechnical Engineering ; Volume 17 D , 2012 , Pages 473-482 ; 10893032 (ISSN) ; Mousavi, S. H ; Sharif University of Technology
2012
Abstract
According to available information and references, water leakage and internal erosion in bodies and foundations of embankment dams are the main reasons of many problems and failures. To reduce this risk in foundation, plastic cut off walls is one of the most reliable solutions. In this research the effect of specimen's age on the mechanical properties of plastic concrete was studied. This paper summarizes the test results which were conducted in unconfined and triaxial state. Plastic concrete specimens were prepared in the laboratory condition using the materials provided from the Silve dam site. Test results have shown that the time and confining pressure extremely affect the mechanical...
Combining Monte Carlo and finite difference methods for effective simulation of dam behavior
, Article Advances in Engineering Software ; Volume 45, Issue 1 , 2012 , Pages 197-202 ; 09659978 (ISSN) ; Zarghami, M ; Sharif University of Technology
Abstract
Monte Carlo simulation provides a probabilistic approach to evaluate the physical behavior of infrastructures. Therefore, the performance could be achieved in a more realistic manner. Within this framework, an innovative software code is developed by combining the Monte Carlo and finite difference methods to predict the behavior of embankment dams after impounding. In order to assess the efficiency of the method, the case study of Chahnimeh-4 dam, located at Southeast of Iran, has been investigated in detail. The behavior of this dam is predicted and compared with the field monitoring by using the Kolmogorov-Smirnov test. The results indicate the robustness of the proposed method and it can...
Dynamic Analysis and Liquefaction Evaluation of Earth Dams, Mahabad Dam case Study
,
M.Sc. Thesis
Sharif University of Technology
;
Jafarzadeh, Fardin
(Supervisor)
Abstract
Liquefaction due to the earthquake loading is one of the most important threats in the earth structure. Analysis of liquefaction of structures such as dam/foundation systems utilizing numerical methods such as finite difference and finite element, can considerably determine the real response of the structures during strong ground motions. Mahabad rockfill dam, located in upper vicinity of Mahabad city, in North-West of Iran, completed and impounded in 1970. This embankment dam was designed as a zoned dam with a slightly inclined impervious clay core and 47.5 m in height. Studying such structures, which have been designed with simple methods in olden times, can recognize the potential risks...
Strength parameters of asphalt concrete used in core zone of earth dams
, Article Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering ; Volume 2 , 2009 , Pages 1558-1561 ; 9781607500315 (ISBN) ; Yousefpour, N ; Sharif University of Technology
Abstract
Strength parameters of asphalt concrete used in earth fill dams' core were studied by conducting cyclic and monotonic triaxial tests on asphalt concrete samples. Results obtained from more than 120 cyclic tests showed that asphalt concrete behaves properly under cyclic loading and specimens stay intact after applying 5000 cycles. Results of monotonic and post-cyclic loading proved that strength parameters of asphalt concrete samples does not change significantly after being subjected to seismic loads. © 2009 IOS Press
Numerical analysis and monitoring of an embankment dam during construction and first impounding case study: siah sang dam
, Article Scientia Iranica ; Volume 25, Issue 2A , 2018 , Pages 505-516 ; 10263098 (ISSN) ; Heidari, M ; Azizyan, Gh ; Sharif University of Technology
Sharif University of Technology
2018
Abstract
Monitoring embankment dams is of crucial importance. In earth dams, the pore pressures, earth pressures, and displacements occurring during construction and function are measured at the time of the first impounding and exploitation by installing essential instruments, and so the dam's performance is evaluated and analyzed. Scope of the present research is the evaluation of Siah-Sang Dam performance through the results of instruments and back analysis, conducted by FLAC software. The Mohr-Coulomb elasticplastic model has been considered as the behavioral model of the dam, and the effect of the upstream shell's materials deformation has been modeled at the time of the initial impounding....
Dambreak Modeling, Flood Routing Studies and Emergency Action Planning- Case study: Mahabad Dam
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor) ; Nazariha, Mehrdad (Supervisor)
Abstract
Due to specific hydraulic characteristics, flood resulting from the failure of constructed dams have produced some of the most devastating disasters of the last two centuries. When dams fail, limited time for right decision making and evacuation, high velocity of floods, population centers located in the vicinity of dam and some important structures lead us to simulate dam breach events, resulting floods and provide emergency action plan for all constructed dams to reduce threats due to potential dam failures. In this thesis, we worked in the area of defining probable breach scenarios for Mahabad storage dam located in west Azarbaijan–Iran, breach simulation, flood routing in downstream area...
Stability analysis of a railway embankment on a collapsible-dispersive stratum under transient flow
, Article 16th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2019, 14 October 2019 through 18 October 2019 ; 2020 ; Sadeghi, H ; Kolahdooz, A ; AECOM; CECI Engineering Consultants, Inc.; CECI Nova Technology Co. Ltd.; et al.; Hwang Chang General Contractor Co., Ltd; SINOTECH Engineering Consultants, Ltd ; Sharif University of Technology
Asian Regional Conference on Soil Mechanics and Geotechnical Engineering
2020
Abstract
Collapsible-dispersive soil is one of the most challenging types of problematic soils having the adverse effects of both collapsible and dispersive soils for construction. A natural occurrence of this type of soil was recently encountered along some part of the Chabahar-Zahedan railway line in Southeast of Iran. Indeed, the construction phase was stopped after facing several geotechnical problems along the railway embankment partly constructed such as local and general subsidence, non-uniform settlements of structural elements, etc. Relatively high natural porosity as well as pore water salinity were found responsible for those problems. Therefore, this study aims to conduct a three-phase...
A numerical study on the effect of salinity on stability of an unsaturated railway embankment under rainfall
, Article 4th European Conference on Unsaturated Soils, E-UNSAT 2020, 19 October 2020 through 21 October 2020 ; Volume 195 , 2020 ; Sadeghi, H ; Ahmadi, M. M ; GDS; VJ Tech ; Sharif University of Technology
EDP Sciences
2020
Abstract
Dispersive soils, as one of the main categories of problematic soils, can be found in some parts of the earth, such as the eastern-south of Iran, nearby the Gulf of Oman. One of the most important factors enhancing the dispersive potential is the existence of dissolved salts in the soil water. The main objective of this study is to explore the influence of water salinity on the instability of a railway embankment due to rainfall infiltration. In order to achieve this goal, the embankment resting on a dispersive stratum is numerically modeled and subjected to transient infiltration flow. The effect of dispersion is simplified through variations in the soil-water retention curve with salinity....
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) ; 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...
Application of fuzzy set theory to evaluate the effect of pore pressure build-up on the seismic stability of Karkheh Dam, Iran
, Article Journal of Earthquake Engineering ; Volume 12, Issue 8 , 2008 , Pages 1296-1313 ; 13632469 (ISSN) ; Bahador, M ; Bahrami, R ; Sharif University of Technology
2008
Abstract
It is a current practice to employ composite claya mixture of clay and aggregates that float within the clayey matrixas the core of embankment dams that have classically been constructed from pure clays. Experience has shown that significant pore pressures could build up during cyclic undrained loading in composite clays. This may threaten dam stability during earthquake loading. However, it is difficult to attribute a single value to excess pore pressure in conventional seismic stability analysis because of the random nature of earthquake loading, leading to uncertainty in the evaluation of factor of safety against sliding. This article evaluates the importance of pore pressure build-up in...
Probabilistic Stability Analysis of a Railway Embankment on Dispersive Strata Subjected to Periodic Rainfall Conditions with Various Patterns
, M.Sc. Thesis Sharif University of Technology ; Ahmadi, Mohammad Mehdi (Supervisor)
Abstract
The importance of rainfall pattern in assessing embankment stability and deformation is widely known. However, many studies have examined an embankment with simple rainfall patterns or used average and maximum ones. The importance of diverse rainfall patterns has also been overlooked in the study of divergent soil stability in the previous study. Therefore, the hydraulic properties of a natural soil with and without salinity potential and the stability analysis of the railway embankment located on this type of soil under various rainfall patterns are investigated. The study area is part of the Zahedan Chabahar National Railway Project, which is located on divergent soil and has high...
Effect of geometry and foundation conditions on the accuracy of the steady state seepage analysis results for rockfill dams
, Article Scientia Iranica ; Volume 14, Issue 3 , 2007 , Pages 212-220 ; 10263098 (ISSN) ; Soleimanbeigi, A ; Sharif University of Technology
Sharif University of Technology
2007
Abstract
One of the most important concerns in designing an embankment dam is seepage analysis. Conventional seepage analyses of embankment dams are performed in two-dimensional (2D) space, in which the impacts of water flow lines seeping from the side abutments are ignored. This fact is especially important if the dam is constructed in a narrow valley. In addition, if the effects of existing underlain faults in the reservoir water discharge rate, under different loading conditions, are to be scrutinized, three-dimensional (3D) modeling of the dam for seepage analysis is inevitable. In this paper, the significance of three-dimensional seepage analyses is emphasized by making a 3D model of a real dam...
New seepage-related design graphs for rock-fill dams
, Article International Symposium on Dams in the Societies of the 21st Century, ICOLD-SPANCOLD - Dams and Reservoirs, Societies and Environment in the 21st Century, Barcelona, 18 June 2006 through 18 June 2006 ; Volume 1 , 2006 , Pages 971-978 ; 0415404231 (ISBN); 9780415404235 (ISBN) ; Jafarzadeh, F ; Sharif University of Technology
Taylor and Francis/ Balkema
2006
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 widthwise flows from side abutments. Moreover, the role of grout curtain extensions into the side abutments and abutment material properties are inevitably neglected when performing seepage analyses in 2D plane. In this paper, two and three-dimensional (3D) models of a rock-fill dam 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 from the...
An effective stress-based parametric study on the seismic stability of unsaturated slopes with implications for preliminary microzonation
, Article Bulletin of Engineering Geology and the Environment ; Volume 80, Issue 10 , 2021 , Pages 7525-7549 ; 14359529 (ISSN) ; Molaei Birgani, M ; Sadeghi, H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The stability of unsaturated slopes under seismic loading has become an important issue over the past few years which is the indication of its practical significance in geoengineering. This study aims at exploring the seismic stability of unsaturated sandy clay and silty clayey sand slopes using 2D limit equilibrium analysis for different slope geometries and ground water levels. To this end, the pseudo-static and the displacement-based sliding block Newmark’s approaches are employed for parametric studies by considering the records of the 2003 earthquake that devastated the city of Bam, in the southeast of Iran. In all analyses, the unsaturated state of the soil materials is taken into...
3D steady state seepage analysis of embankment dams
, Article Electronic Journal of Geotechnical Engineering ; Volume 10 F , 2005 ; 10893032 (ISSN) ; Jafarzadeh, F ; Sharif University of Technology
2005
Abstract
Steady state seepage analysis of embankment dams is one of the most significant stages in the designing process. Currently, most seepage modeling of embankment dams is performed in two dimensions, often for the highest section, which include several simplifications. In this way, the effect of watertight elements such as grouting curtains in side abutments as well as their material properties is not taken into account in seepage analysis results. Especially if the dam is located in a narrow valley or the effect of existing faults beneath the dam is to be investigated, the results of the two-dimensional seepage analysis differ from those of three-dimensional (3D). In this paper, the...
Floating bridge modeling and analysis
, Article Scientia Iranica ; Volume 12, Issue 2 , 2005 , Pages 199-206 ; 10263098 (ISSN) ; Paein Koulaei, R. T ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
This paper presents an overview of a study on the design and analysis aspects of the Lake Urmia Bridge in Iran. For years there have been several detailed investigations on this subject. Here, these alternatives are discussed and, then, results of analyses for a proposed solution, a floating bridge, are presented. These aspects include environmental loads, structure and the mooring system. © Sharif University of Technology