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Applicability of rigid block based approaches in predicting sandy slope displacements by 1g shaking table tests
, Article Soil Dynamics and Earthquake Engineering ; Volume 126 , 2019 ; 02677261 (ISSN) ; Farahi Jahromi, H ; Rajabigol, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Various approaches have been developed by researchers to predict earthquake induced landslide displacements. This study evaluates the applicability of these approaches on sandy slopes. For this purpose, nine physical models are constructed inside a rigid box and thirty-six shaking table tests are conducted. Dynamic responses are then converted to the full scale model by applying similitude laws. Five statistical criteria are applied to compare the measured and predicted displacements and evaluate the precision of the approaches. By combining the outcomes and using a scoring procedure, the approaches are scored. Consequently, the approaches of Fotopoulou and Pitilakis [23] and Hsieh and Lee...
Studying Dynamic Response of Landslides Using 1g Shaking Table Tests and Comparing with Analytical Methods
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Evaluation of seismic slope stability is very important because it has a decisive role in stimating the earthquake damages. According to the past studies, medium to large earthquakes usually cause thousands landslides and many casulties and financial damages. Since nearly half a century ago, several methods have been developed for predicting the occurrence of landslides and permanent movements, but due to the influnce of many parameters on the seismic stability of the slopes further researches is needed.
In present study, to investigate the dynamic behavior of the slopes, four physical models of slopes had been made on shaking table in Sharif university of technology. These slopes have 3...
In present study, to investigate the dynamic behavior of the slopes, four physical models of slopes had been made on shaking table in Sharif university of technology. These slopes have 3...
Experimental study and modeling of gravity drainage during WAG process in fractured carbonate rocks
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 27, Issue 3 , October , 2008 , Pages 103-113 ; 10219986 (ISSN) ; Badakhshan, A ; Taghikhani, V ; Rashtchian, D ; Gotbi, C ; Sajadian, V. A ; Sharif University of Technology
2008
Abstract
The experimental study and modeling of gravity drainage during Water Alternative Gas Injection, WAG process, in carbonate rock for one of the Iranian off-shore reservoir at lab-scale were carried out. The mechanism of gravity drainage during the WAG process, and its contribution to the oil recovery in the fractured carbonate reservoirs were also studied. In the WAG process alternatively gas is injected during the process and gravity drainage could be happened. Changes in the block dimensions, rock properties, oil properties, gas properties, and fractures properties and their effect on the amount of oil recovered during the gravity drainage mechanism were studied. It would be worth mentioning...
The effect of open trench on active foundation isolation using physical modeling
, Article 6th International Conference on Physical Modelling in Geotechnics - Physical Modelling in Geotechnics - 6th ICPMG '06, Hong Kong, 4 August 2006 through 6 August 2006 ; Volume 2 , 2006 , Pages 1217-1222 ; 0415415861 (ISBN); 9780415415866 (ISBN) ; Ghayoomi, M ; Bahmanpour, A ; Sharif University of Technology
2006
Abstract
Dynamic loads in many projects cause vibration in soil. The propagated energy has a destructive effect on the foundation of the adjacent structures. One of the suitable methods for preventing these harmful waves is active isolation. In this paper the mentioned phenomena is studied by conducting some physical model tests. The loose sandy models are excited by impact type load of a tamper and the response for models with and without trench are measured at different points. Two types of closed form or continuous trenches are used. In closed form trench models, the effect of trench on acceleration attenuation and the ratio of vertical to horizontal accelerations were investigated. In continuous...
Investigation of Dynamic Response of Shallow Foundations on Sandy Soil to Horizontal Harmonic Loading by Physical Model Tests
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
The most important step in current dynamic analysis of machine foundations is determining dynamic impedance functions. Impedance functions are defined as ratios of applied force or moment to induced displacement or rotation angle of foundation. In this research, horizontal dynamic response of foundation on homogeneous halfspace was investigated using physical modeling. Soil medium was built in a 1mx1mx0.8m steel box whose interior walls were covered by 0.1m of sawdust (a material with high damping). In order to prevent possible reflection of waves, this cover was extended to the box bottom with 0.2 m thickness. Sand raining method was used to build soil medium. In this method, with...
Liquefaction Effects on (a) Individual and Group of Capless Piles and (b) Group of three Piles under Real and Artificial Earthquakes
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
In the areas where the soil beneath the foundation is made of loose to semi-consolidated sand or noncohesive silts, Buildings and bridges are usually built on the pile foundations. One important issue that must be considered in the design of piles in saturated sandy soils, is liquefaction potential of saturated sandy soil under earthquake loads. During the earthquake, saturated sandy soil faces the sudden loss of shear strength in other word it liquifies . Liquefied Soil acts like a viscous fluid. This behaviour considerably increases the soil deformation and consequently the widespread disruption of soil layers, causes large deformation and applies great amount of forces on the piles...
Physical Modeling of Buried Pipelines Response due to Earthquake-Induced Landslide
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
In this dissertation, the response of buried pipelines in slopes which have become unstable during earthquake induced landslides is investigated. The Sharif University of Technology shaking table was used for modeling this phenomenon.Three tests were performed so that in the first and second ones, three pipes were placed in different positions due to slope and the supports were elastic cylinders. In third test, there were four pipes with simple supports at the test-box walls.The pipes in every test were buried in the depth of 11 centimeters and they were all made of aluminum with the outside diameter of 16 millimeters and thickness of 1 millimeter. Also, they were all in the bending mode due...
The Study of Soild Slope Seismic Response using the Physical Model Test on the Shaking Table
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Evaluation of seismic slope stability is very important because it has a decisive role in estimating the earthquake damages. According to the past studies medium to large earthquakes, usually cause thousands landslides and many casualties and financial damages. Since nearly half a century ago, several methods have been developed for predicting the occurrence of landslides and permanent movements, but due to the influence of many parameters on the seismic stability of the slopes further researches is needed.In present study, to investigate the dynamic behavior of the slopes, three physical models of slopes had been made on shaking table in Sharif University of technology. These slopes have...
Physical Modeling of a Heat Exchanger Pile under Thermo-mechanical Loading in Sand
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Heat exchanger piles are innovative technologies used to harvest heat from shallow ground. Heat exchanger pile, also known as energy pile, transfers mechanical (structural) loads to the ground while acting as a heat exchanger. Heat extraction in winter and heat rejection during summer changes the pile, pile-soil interaction and the surrounding soil temperature. Therefore, pile temperature increments have been recognized as a new factor of controlling the behavior of energy piles in recent decades. Besides, thermal cyclic loadings may affect the serviceability and geotechnical performance of heat exchanger piles. Physical models provide an affordable experimental medium through which new...
Investigation of Dynamic Response of Shallow Foundations on Layered Soil Medium by Physical Modeling
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Dynamic impedance functions method is most recent approach in the analysis of soil-foundation dynamic interaction, and presented for massless rigid foundations. Impedance functions are frequency dependent functions, and used to obtain dynamic response of foundation with arbitrary mass subjected to dynamic loading of any frequency and magnitude. The important assumptions for appropriate useof mentioned method are rigidity of foundation and visco-elastic behavior of the soil beneath the foundation. In this study, experimental vertical impedance functions of square and circular foundations have been investigated,using physical modeling tests. A granular soil layer with finite thickness...
Numerical Modelling of Buried Pipelines Reinforcement in Slopes under Dynamic Loads Based on Physical Model Tests
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Behavior and retrofit methods of buried pipes in slope under dynamics loading are investigated in FLAC 2D. Hysteretic damping is used to represent of soil damping and compared with Rayleigh damping model. Mohr-coloumb and elasto-plastic model are adopted for soil and pipe constitutive model respectively. Young modulus is defined as function of stress level and shear strain. Displacements and accelerations of numerical model was compared with the physical model on the shaking table tests. Influence of different parameters like young modulus, reference shear strain and dilation angel is investigated. Interaction model between soil and pipe is considered as elasto-plastic with separation and...
Study of the Dynamic Response of Foundation Resting on Sandy soil by Means of Physical Modeling
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Experimental investigations in the subject of dynamic response of machine foundations for verification of many theoretical studies are scant. The effects of several factors, namely, shape and weight of foundation, frequency of vibration, depth of embedment, dynamic load levels and type of loading (harmonic and impact) on dynamic response of foundation were studied experimentally.Also, the current methods of machine foundation analysis mostly are based on the concept of the dynamic impedance function. Therefore, using these tests results, impedance functions for the model are calculated and presented. The physical model tests were carried out in a steel container with dimension of 1×1×0.9 m....
Evaluating the Usage of Polystyrene Protection Behind the Buried Pipelines on Dynamic Response of Soil Slope with using a 1g Shaking Table
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
Studying of slope stability under dynamic loading such as earthquakes is one of the critical issues. This importance is attributed to many of the slopes are located in urban areas, either around them or in the important buildings and infrastructure. Thus, evaluation of slope’s behavior is very essential. On the other hand, preparing fundamental arrangements to improve the current situation, surrounding and buried areas in the slope is necessary.
In this study, a physical model of Tehran's slopes by 0.1 ratio with pipes that have been retrofitted by plastofoam developed. This model was tested on the shaking table under dynamic loading. The dimensions of the slope were 1 meter width, 3...
In this study, a physical model of Tehran's slopes by 0.1 ratio with pipes that have been retrofitted by plastofoam developed. This model was tested on the shaking table under dynamic loading. The dimensions of the slope were 1 meter width, 3...
Investigating the Behavior of the Group Energy Pile in Unsaturated Silty Sand Soil Using Physical Modelling
, M.Sc. Thesis Sharif University of Technology ; Jafarzadeh, Fardin (Supervisor)
Abstract
A physical model has been developed in the advanced soil mechanic lab of the sharif university of technology. This model has been used to investigate the thermo-hydro-mechanical behavior of the group energy pile, which was embedded in the unsaturated silty sand soil. This model contains a steel soil box, 4 aluminum piles, strain gauges, the total pressure cells, the thermocouples, and the mechanical load. Three sets of tests were conducted on these piles. In the first the thermal cycles were applied on 1 pile and in the second and third tests, the number of the energy piles was 2 and 3, respectively. The result has shown there was a permanent settlement at the end of the thermal cycles....
Effect of size and geometry of gold nanostructures in performance of laser-based hyperthermia: A multiscale- multiphysics modelling
, Article 3rd International Symposium on Optics and its Applications, 1 October 2015 through 5 October 2015 ; Volume 673, Issue 1 , 2016 ; 17426588 (ISSN) ; Razaghi, M. R ; Hormozi Nezhad, M ; Rafii Tabar, H ; Sasanpour, P ; Abdus Salam International Center for Theoretical Physics; et al.; International Society for Optics and Photonics (SPIE); Optical Society (OSA); Russian-Armenian (Slavonic) University; TeraTech Laboratory (BMSTU) ; Sharif University of Technology
Institute of Physics Publishing
Abstract
The importance of hyperthermia as a promising method in disruption and removal of cancerous cells is well understood. One of the effective options of concentration of heat within a specific tissue is using laser and exploiting absorption properties of metallic nanostructures. In this report, the geometrical effect of gold nanostructures in the performance of laser based hyperthermia has been analyzed. The analysis is based on the consideration of absorption properties of gold nanostructures, interaction of laser light with a specific tissue containing nanostructures and the effect of generated heat on elevation of temperature inside the tissue. The analysis is performed using Mie theory (for...
Dynamic compaction method in physical model tests
, Article Scientia Iranica ; Volume 13, Issue 2 , 2006 , Pages 187-192 ; 10263098 (ISSN) ; Sharif University of Technology
Sharif University of Technology
2006
Abstract
In this paper, physical modeling tests are conducted to study some aspects of the dynamic compaction method. The loose models are prepared with dry sand. Four cylindrical tampers with different weight and cross section areas are used for compaction of the models and dropped from various heights. Strain gage type total stress measuring sensors are placed at different levels inside the model to measure the transferred vertical stresses due to collision of the tamper with the surface of the models. The typical stress time histories are presented. Improvement depth and crater depth and diameter created on the model surface are studied, among the various parameters affecting the phenomena. Using...
Energy dissipation in saturated loose sand models in one and two-dimensional shaking table tests
, Article 6th International Conference on Physical Modelling in Geotechnics, ICPMG'06, Hong Kong, 4 August 2006 through 6 August 2006 ; Volume 1-2 , 2006 , Pages 463-467 ; 041541587X (ISBN); 9780415415873 (ISBN) ; Hamidi, A ; Lotfiazad, F ; Sharif University of Technology
2006
Abstract
In this paper the relation between dissipated energy and pore pressure is studied using 1 g shaking table test results. Toyoura sand is used for the physical models. Both one and two dimensional variable phase loadings are applied to the models. Shear work was calculated using accelerations and displacements and normalized to the mean effective stress. Pore water pressure was also normalized to the vertical effective stress. The results show that the pore pressure has a unique relationship to the shear work no matter whether the shaking is one or two dimensional. The results also show that the generated normalized pore pressure is independent of loading type and confinement. © 2006 Taylor &...
Selection of empirical formulae for design of stepped spillways on RCC dams
, Article World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability - Proceedings of the 2011 World Environmental and Water Resources Congress, 22 May 2011 through 26 May 2011 ; May , 2011 , Pages 2508-2517 ; 9780784411735 (ISBN) ; Attari, J ; Sharif University of Technology
2011
Abstract
Stepped spillways have been widely used in Roller Compacted Concrete (RCC) dams in the recent decades. Considering complexity of hydraulics of stepped chutes, their initial design involves pre-selection of some empirical formulae for calculation of flow characteristics and design parameters. In this paper, accuracy of several empirical formulae, proposed for calculating locations of aeration inception (LI), uniform flow (Lu) and rate of energy dissipation (ΔH/Hmax), were compared in relation to results of physical model tests of four stepped spillways and the preferred formulae, providing least amounts of relative errors, were identified. Such a feedback will be helpful for improvement of...
Scour hole influence on turbulent flow field around complex bridge piers
, Article Flow, Turbulence and Combustion ; Volume 97, Issue 2 , 2016 , Pages 451-474 ; 13866184 (ISSN) ; Ataie Ashtiani, B ; Sharif University of Technology
Springer Netherlands
Abstract
Experimental results of detailed flow measurements using an Acoustic-Doppler Velocimeter (ADV) around a complex bridge pier (CBP) are presented. The pier consists of a column, a pile cap (PC) and a 2×4 pile group. The time-averaged velocities, turbulence intensities, and Reynolds stresses are studied and presented at different horizontal and vertical planes. Streamlines obtained from the velocity fields are used to show the complexity of the flow around the pier. It is shown that the main feature of the flow responsible for the entrainment of the bed sediments is a contracted (pressurized) flow below the PC toward the piles. A deflected flow around the PC and a strong down-flow along its...
Dynamic impedance functions of machine foundations on sandy soils by physical model tests
, Article Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 5 October 2009 through 9 October 2009, Alexandria ; Volume 1 , 2009 , Pages 478-481 ; 9781607500315 (ISBN) ; Mashhadi, H. G ; Sharif University of Technology
Abstract
In order to improve new methods of design of machine foundations by means of impedance function, implementation of experimental investigations to calibrate these methods is vital. The physical model tests were carried out in a steel container with dimension of 1×1×0.9 m. The Babolsar sand was employed in the model. To eliminate reflection of elastic waves, a sawdust layer was used in the lateral walls and bottom of the container. Also, in order to have homogeneous medium with unified density, air pluviation of sand method was employed. Response of the models to harmonic excitations was measured using various instruments deployed around the foundation. Results of the tests are shown in the...