Loading...
Search for: lateral-spread
0.006 seconds
Total 27 records

    Numerical investigation into the effects of geometrical and loading parameters on lateral spreading behavior of liquefied layer

    , Article Acta Geotechnica ; 2013 , Pages 1-13 ; 18611125 (ISSN) Pak, A ; Seyfi, S ; Ghassemi, A ; Sharif University of Technology
    2013
    Abstract
    Numerical simulation of liquefaction-induced lateral spreading in gently sloped sandy layers requires fully coupled dynamic hydro-mechanical analysis of saturated sandy soil subjected to seismic loading. In this study, a fully coupled finite element model utilizing a critical-state two-surface-plasticity constitutive model has been applied to numerically investigate the effects of surface/subsurface geometry on lateral spreading. Using a variable permeability function with respect to excess pore pressure ratio is another distinctive feature of the current study. The developed code has been verified against the results of the well-known VELACS project. Lateral spreading phenomenon has been... 

    , M.Sc. Thesis Sharif University of Technology Boushehrian, Ahmad (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Loads from laterally spreading ground have been a major cause of damages to pile foundations in past earthquakes. Analysis of case histories have shown that damages are particularly intense when a nonliquefiable surface crust layer spreads laterally over underling liquefied layers. In this research the effect of lateral spreading due to liquefaction on single piles embede in a gently sloping ground has been investigated. Finite element method using OpenSees is used to model the pile and embedded soil. The soil profile for all models consisted of a nonliquefiable crust layer overlying loose sand with Dr = 30-35% overlying dense sand with Dr = 70-80%. The effect of geometric properties such as... 

    , M.Sc. Thesis Sharif University of Technology Padash, Hadi (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    During the past earthquakes in all over the world, the piles have had serious damages in soils with liquefaction potential. During an earthquake, liquefaction occurs in some parts of ground with mild slope and saturated and soft granular soil. Afterwards lateral spreading induced by liquefaction incurs irreparable damages on structures and piles particularly. Observing these damages, the researchers and engineers have conducted more surveys and investigations to studying the behavior of piles in granular soils with liquefaction potential and also interactions between  soil  and pile.  In  these  researches,  they have  modeled  the  interactions between  soil  and pile.  However  there are ... 

    Study of the behavior of pile groups during lateral spreading in medium dense sands by large scale shake table test

    , Article International Journal of Civil Engineering ; Vol. 12, Issue. 3 , 2014 , pp. 374-391 ; ISSN: 17350522 Kavand, A ; Haeri, S. M ; Asefzadeh, A ; Rahmani, I ; Ghalandarzadeh, A ; Bakhshi, A ; Sharif University of Technology
    Abstract
    In this paper, different aspects of the behavior of 2×2 pile groups under liquefaction-induced lateral spreading in a 3-layer soil profile is investigated using large scale 1g shake table test. Different parameters of the response of soil and piles including time-histories of accelerations, pore water pressures, displacements and bending moments are presented and discussed in the paper. In addition, distribution of lateral forces due to lateral spreading on individual piles of the groups is investigated in detail. The results show that total lateral forces on the piles are influenced by the shadow effect as well as the superstructure mass attached to the pile cap. It was also found that... 

    Investigation on the Effect of Liquefaction-Induced Lateral Spreading on a Flexible Pile Group and Mitigation Measures for These Effects by Physical Modeling

    , M.Sc. Thesis Sharif University of Technology Raisianzadeh, Javad (Author) ; Haeri, Mohesn (Supervisor)
    Abstract
    Liquefaction-induced lateral spreading is a known cause of severe damages to deep foundations during past earthquakes. Lateral spreading often takes place in gently sloping grounds which consisted of saturated loose cohesionless soil deposits. Several researchers during recent years have been studying the behavior of piles and soil-pile interaction under lateral spreading but there are still many unknowns in this regard. Also with observing catastrophic damages during past earthquakes caused by lateral spreading, developing proper mitigation measures for existing vulnerable piles against this phenomenon is a necessary act. In the present research, the behavior of a 3x3 flexible pile group... 

    Effect of Lateral Spreading Due to Liquefaction on Piles, Numerical Simulation with OpenSees

    , M.Sc. Thesis Sharif University of Technology Ghasemi Fard, Ali (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Lateral spreading due to liquefaction and resulting destruction of buildings is important in Iran because of high seismicity and important infrastructure near south and north coasts of Iran. Lateral spreading is vast lateral movement of sloping ground or level ground ending in an opening like river which is caused by earthquake inducedliquefaction. For considering the effects of lateral spreading during design of deep foundations of structures in a susceptible area, one needs to determine the lateral loads on piles under lateral spreading. Present study investigates the behavior of a 3x3 pile group against lateral loads due to lateral spreading with numerical methods using OpenSees software.... 

    An Investigation on the Effects of Liquefaction Induced Lateral Spreading on Deep Foundations and Development of Mitigation Measures Using 1g Shake Table Tests

    , Ph.D. Dissertation Sharif University of Technology Kavand, Ali (Author) ; Haeri, Mohsen (Supervisor) ; Rahmani, Iraj (Co-Advisor)
    Abstract
    Liquefaction induced lateral spreading is defined as the lateral displacement of mildly sloping grounds or those ending in free faces as a result of liquefaction in subsurface soil layers. Damages imposed by lateral spreading on pile foundations supporting different types of structures such as ports, bridges and buildings are usually observed in large earthquakes. These potential damages are of high degree of importance in southern and northern coastal areas of Iran where several ports and critical facilities are located. River banks all over the country where bridge piers exist are also among the areas prone to potential damages. Evaluation of the effects of lateral spreading on existing... 

    Linear and Non-linear Dynamic Analysis of Full Scale Shaking Table Laminar Shear Box to Study the Effects of Lateral Spreading Due to Liquefaction on Deep Foundations

    , M.Sc. Thesis Sharif University of Technology Kazemi Taskoh, Amin (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Liquefaction-induced lateral spreading has imposed severe damages to many important structures supported on pile foundations during past earthquakes. As a result, evaluation of pile response to lateral spreading is an important step towards safe and resistant design of pile foundations against this destructive phenomenon. The boundary conditions for physical modeling in problems of earthquake geotechnical engineering have significant influence on the test results. In order to reduce the undesirable effects of boundaries on the model responses, the flexible containers are used. The flexible containers are those in which the shear stiffness of the walls is proportional to the soil inside. A... 

    Numerical Modeling of the Dynamic Behavior of Piles and Pile Groups Due to Liquefaction- Induced Lateral Spreading

    , M.Sc. Thesis Sharif University of Technology Pakzad, Amin (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    The phenomenon of lateral spreading occurs as a consequence of earthquakes induced liquefaction in grounds with mild slopes or ending to an opening. This phenomenon has caused many damages to deep foundations and associated structures. Therefore, it is necessary to study and estimate the forces which may be induced by lateral spreading to these structures. Due to the complex mechanism of the effect of lateral spreading on the piles, various tests have been carried out in the form of shaking table as well as centrifuge tests. According to the results of these tests, the forces applied to the piles are significant and can cause crucial damages to deep foundations. On the other hand, because... 

    Prediction of lateral spreading displacement on gently sloping liquefiable ground

    , Article Geotechnical Frontiers 2017, 12 March 2017 through 15 March 2017 ; Issue GSP 281 , 2017 , Pages 267-276 ; 08950563 (ISSN) Ghasemi Fare, O ; Pak, A ; Geo-Institute (G-I) of the American Society of Civil Engineers; Industrial Fabrics Association International (IFAI) ; Sharif University of Technology
    American Society of Civil Engineers (ASCE)  2017
    Abstract
    A fully coupled numerical analysis using Biot's theory with u-p formulation considering variable permeability during liquefaction is used in this study to simulate liquefaction induced lateral spreading phenomenon. A centrifuge test performed on liquefiable soil at Rensselaer Polytechnic Institute is simulated using the developed model. The numerical results are in good agreement with experimental observations. A number of numerical simulations under different geometric, site-specific, and ground acceleration parameters have been carried out in the course of this study. Based on the statistical analysis conducted on the results of 31 different models, a new relation is proposed for... 

    A Neuro-Fuzzy model for prediction of liquefaction-induced lateral spreading

    , Article 8th US National Conference on Earthquake Engineering 2006, San Francisco, CA, 18 April 2006 through 22 April 2006 ; Volume 13 , 2006 , Pages 8001-8008 ; 9781615670444 (ISBN) Haeri, S. M ; Khalili, A ; Sadati, N ; Sharif University of Technology
    2006
    Abstract
    Lateral spreading generated by earthquake induced liquefaction, is a major cause for significant damage to the engineered structures, during earthquakes. Knowing the amount of displacement which is likely to occur due to the lateral spreading, will lead to better construction policies, and will reduce unexpected damages. A Neuro-Fuzzy model based on subtractive clustering is developed to predict the amount of lateral spreading expected to occur due to an earthquake. A large database containing the case histories of observed lateral spreading during seven major earthquakes of the past is used for training and evaluating the models. The results of this study show that Neuro-Fuzzy method serves... 

    Response of a group of piles to liquefaction-induced lateral spreading by large scale shake table testing

    , Article Soil Dynamics and Earthquake Engineering ; Volume 38 , 2012 , Pages 25-45 ; 02677261 (ISSN) Haeri, S. M ; Kavand, A ; Rahmani, I ; Torabi, H ; Sharif University of Technology
    2012
    Abstract
    Liquefaction-induced lateral spreading has imposed severe damages to many important structures supported on pile foundations during past earthquakes. As a result, evaluation of pile response to lateral spreading is an important step towards safe and resistant design of pile foundations against this destructive phenomenon. Current paper aims to study the response of a group of piles subjected to liquefaction-induced lateral spreading using a large scale 1-g shake table test. General test results including time-histories of accelerations, pore water pressures, displacements and bending moments are presented and discussed in this paper. In addition, distribution of lateral soil pressure on... 

    Numerical Simulation of Ground Displacement Induced by Lateral Spreading Phenomenon

    , M.Sc. Thesis Sharif University of Technology Ghasemifare, Omid (Author) ; Pak, Ali (Supervisor)
    Abstract
    The lateral movement of a liquefiable layer on gently slopes is the most visible and devastating type of liquefaction-induced ground failure. Occurrence of liquefaction in sloping ground causes large deformations on ground surface, which may lead to several meters in some cases. Recent earthquakes have shown that this phenomenon causes severe damages to coastal structures, piers of bridges and life-lines, by exerting large lateral forces. In this research, a fully coupled two-dimensional dynamic analysis has been used to simulate the lateral spreading phenomenon and to evaluate the magnitude of deformations occurred in liquefiable soils. The critical state bounding surface elastic-plastic... 

    Numerical Study of the Effect of Liquefaction-Induced Lateral Spreading on a group of piles

    , M.Sc. Thesis Sharif University of Technology Dehnavi, Alireza (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    The behavior of pile foundations under earthquake loading is an important issue that affects the performance of structures. Design procedures have been developed for evaluating pile behavior under earthquake loading; however, the application of these procedures to cases involving liquefiable ground is uncertain. The performance of piles in liquefied soil layers is much more complex than that of non-liquefying soil layers because not only the superstructure and the surrounding soil exert different dynamic loads on pile, but also the stiffness and shear strength of surrounding soil diminishes over time due to both non-linear behavior of soil and pore water pressure generation. In this... 

    , M.Sc. Thesis Sharif University of Technology Seyfi, Sahand (Author) ; Pak, Ali (Supervisor)
    Abstract
    Lateral spreading is a common mode of earthquake-induced failure that usually occurs as a result of liquefaction in gently sloped sandy layers. Numerical simulation of this phenomenon requires fully coupled analysis of displacement of solid sand particles and pore water pressure under seismic loading. Predicting occurrence of initial liquefaction and sub-sequent ground movement requires employing an efficient and robust constitutive model that can predict the undrained behavior of saturated sand under different conditions. In this study, a fully coupled finite element code “PISA” utilizing a critical state two-surface plasticity constitutive model, proposed by Manzari and Dafalias (1997),... 

    Numerical Study on the Effects of Liquefaction Induced Lateral Spreading on Rigid Waterfront Structures

    , M.Sc. Thesis Sharif University of Technology Khosrojerdi, Mahsa (Author) ; Pak, Ali (Supervisor)
    Abstract
    Lateral Spreading, which usually occurs as a consequence of liquefaction in gently sloped loose saturated sand layers, is known to be a major source of earthquake-induced damages to structures such as bridge piers, quay walls, pipelines and highway/railway. Therefore, evaluation of liquefaction potential and using appropriate methods for prediction of the adverse events of lateral spreading is of great importance. In this study, numerical modeling has been used to study of lateral spreading phenomenon behind rigid waterfront structures. In order to perform a numerical modeling of lateral spreading and also designing the structures exposed to its effects, the interaction of the soil solid... 

    Physical Modeling of Effect of Liquefaction-Induced Lateral Spreading on Single Piles

    , M.Sc. Thesis Sharif University of Technology Torabi, Hooman (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Pile foundations suffered severe damages during the past earthquakes in all around the world. These damages were more severe in laterally spreading grounds and they mostly have been observed in gently sloping grounds and coastal areas. In these cases, Pile foundations not only are subjected to structures inertial loads and kinematic loads of liquefied soil but also lateral spreading intensifies damages. Thus, in the recent decade, several researches have been conducted to investigate the behavior of pile foundations in liquefiable and laterally spreading grounds, however, some uncertainties still remain in modeling of soil-pile interaction. In this study, the effects of liquefaction- induced... 

    Numerical Simulation of Effect of Lateral Spreading Due to Liquefaction on Piles and Estimate Soil Lateral Displacement Pattern by Image Processing

    , M.Sc. Thesis Sharif University of Technology Sayaf, Hiva (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    In recent earthquakes piles have been severely damaged due to liquefaction-induced lateral spreading. Liquefaction causes lateral spreading in gently sloped saturated soft granular soils, leading to significant damage in structures and deep foundations. Although in recent years many studies have focused on different aspects of this phenomenon, the complex nature of the dynamic interaction between piles and liquefied soil is not yet fully understood. This potential damages are of high degree of importance in southern and northern coastal areas of Iran where several ports and critical facilities are located. The present study focuses on the behavior of a 2x2 pile group against lateral loads... 

    An Investigation On The Effects Of Liquefaction Induced Lateral Spreading on a 3×3 Pile Group Using Shake Table Test and Laminar Shear Box and Consideration of Boundary Conditions on Physical Model Results

    , M.Sc. Thesis Sharif University of Technology Salaripour, Saman (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Lateral spreading is defined as finite lateral displacement of mildly sloping grounds or those ending in free faces induced by liquefaction. Severe damages of pile groups due to lateral spreading in past earthquakes has been reported. Since earthquake is unavoidable, it is necessary to study the response of piles, especially pile groups, to liquefaction induced lateral spreading. Until now, a number of methods have been developed by researchers for design of deep foundations against lateral spreading, but reported failure of piles in last earthquakes indicates that these methods are associated with high uncertainties. This is due to the lack of laboratory and experimental data to evaluate... 

    Physical Modeling of Group Pile Response to Liquefaction-Induced Lateral Spreading by Shaking Table Tests

    , M.Sc. Thesis Sharif University of Technology Asefzadeh, Arian (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    In recent earthquakes piles have been severely damaged due to liquefaction-induced lateral spreading. Liquefaction causes lateral spreading in gently sloped saturated soft granular soils, leading to significant damage in structures and deep foundations. Although in recent years many studies have focused on different aspects of this phenomenon, the complex nature of the dynamic interaction between piles and liquefied soil is not yet fully understood. Thus more studies in this regard is inevitable. The present research focuses on the discussion and analysis of two large scale shaking table tests of 2x2 and 3x3 group piles. A three layer soil profile was used for the model, consisting of one...