Hamid Alielahi

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The surrounding soil of pile foundations may settle as a result of fill placing or even consolidation, especially in soft grounds. If the soil settlement is higher than the pile’s, Negative Skin Friction (NSF) happens. NSF can have a hanging effect on piles which causes pile settlement (downdrag) and applies extra force (dragload) on pile. This stu...

In this research, the seismic behavior of the back-to-back MSE walls has been assessed in a probabilistic approach using the fragility curves and the effect of the overlapping length of the metal strips on the vulnerability of this type of walls has been investigated. To this end, the back-to-back MSE walls are simulated using FLAC2D finite differe...

Shored Mechanically Stabilized Earth (SMSE) walls are types of soil retaining structures that increase soil stability under static and dynamic loads. The damage caused by an earthquake can be determined by evaluating the probabilistic seismic response of SMSE walls. This study aimed to assess the seismic performance of SMSE walls and provide fragil...

In earthquakes, foundations of structures may encounter damages due to faulting. To address this issue, numerous innovative mitigation methods have been introduced. Among these, an efficient solution involves constructing a trench wall filled with a material capable of not only absorbing the faulting energy but also diverting the propagation route...

امروزه ایده استفاده از روش‌های کاهش فشار جانبی خاک به منظور طراحی بهینه دیوارهای حائل به‌ویژه در مناطق لرزه‌خیز، اهمیت ویژه ای پیدا کرده است. یکی از این روش‌ها، استفاده از لایه‌هاي تراکم‌پذیر ژئوفوم در پشت دیوارهای حائل می باشد. از این رو، در این مقاله بهبود عملکرد لرزه ای دیوارهای حائل منعطف به کمک لایه‌های ژئوفوم EPS مورد مطالعه قرار گرفته است. د...

Recent studies found that some structural damage can be attributed to the effect of surface waves. A shallow underground structure may be heavily influenced by surface waves, which makes to lose energy over distance more slowly than body waves. This study deals with evaluating the effect of Rayleigh waves (R-waves) interaction with underground cavi...

Dynamic Compaction (DC) with tamping is one of the soil improvement methods and has been significantly accepted due to its advantages over other soil improvement methods. In this paper, an attempt has been made to use the fuzzy logic and Sugeno inference system to investigate the effect of the parameters involved in soil improvement operations usin...

Determining bearing capacity of piles has always been challenging for geotechnical engineers. Various methods are recognized for determining pile capacity, like analytical approaches based on laboratory testing and pile load tests which are time-consuming and expensive. Hence, a series of empirical approaches were developed to predict the pile capa...

This study presents the performance of improved soft soil with prefabricated vertical drains by considering smear zone characteristics in the Mahshahr preloading project as a case study. An observational approach was used to predict the ultimate settlement (Sult), and then the numerical simulations were carried out using ABAQUS software with equiva...

In this study, the seismic behavior of the Persian Gulf Bridge’s complicated basin was evaluated using the FLAC 2D software based on the finite difference method (FDM). A 1D modeling for the soil profile at each pier position of the bridge and a 2D modeling for all piers located on the sedimentary basin was performed. To verify the results of the n...

The growing use of underground structures, specifically to facilitate urban transportation, highlights the need to scrutinize the effects of such spaces on the seismic ground response as well as the surrounding buildings. In this regard, the seismic ground amplification variations in the vicinity of single and twin box-shaped tunnels subjected to S...

This study deals with the performance evaluation of the soil improvement using surcharge preloading techniques with prefabricated vertical drains (PVDs) for the Mahshahr oil storage tanks project as a case study. First, the ultimate settlement values were predicted using observational methods, then, to determine the modified preloading design param...

In the recently developed performance-based design method, permanent displacement is a key parameter for evaluating seismic performance quay walls, which can be achieved by fully dynamic and simple pseudo-static limit equilibrium (PS-LE) based methods. PS-LE methods have some ambiguities concerning the calculation of yield acceleration (ay); theref...

This study deals with the soil-structure interaction induced by underground tunnels and surface structures subjected to SV waves using the finite element method (FEM). To this end, the surface structures’ lateral displacement and drift due to the effects of several dimensionless parameters, including the tunnel depth, the surface distance between t...

The need to construct structures on soft and unstable soils due to the appropriate technical and economic conditions has led to the development of various soil remediation methods. Moreover, the experience obtained from recent earthquakes has indicated the influence of sites’ stiffness on the surface seismic ground response. One of the ways to incr...

In this paper, the effect of selecting the earthquake equivalent acceleration coefficient on the seismic performance of the broken-back quay wall of Pars Petrochemical Port has been studied as a case study. In this regard, the recommendations and relationships presented in the old and new editions of the Japanese Maritime Codes (OCDI, 2002, 2009) a...

In this research, four proposed methods based on the results of the Cone Penetration Test (CPT), as well as two proposed methods based on the standard penetration test (SPT), have been used to estimate the bearing capacity of five bored concrete piles. The aforementioned piles have been constructed in the Shahid Rajaee Port Project in the west of B...

In this study, the seismic interaction of surface foundations and underground cavities was investigated. For this purpose, a parametric study of geometric dimensions of the foundation and cavity, their location, and the effect of the interaction between surface foundations and underground cavities was evaluated. The variable parameters include the...

دینامیک خاک یکی از زیر شاخه¬های مکانیک خاک است که خواص مهندسی و رفتار خاک ها را تحت بارهای دینامیکی مورد بررسی قرار می¬دهد. از تفاوت¬های های اصلی مکانیک خاک و دینامیک خاک، نوع بارگذاری است. در دینامیک خاک، بر خلاف مکانیک خاک، بارگذاری تابع زمان بوده و در هر لحظه با زمان تغییر می¬کند. همچنین در مسائل دینامیک خاک به دلیل لزوم در نظرگیری اثرات ناشی از...

Nowadays, due to the development of civilization and lack of space for city developments, the municipal waste is buried in places called Landfill. It is obvious that the demolition of landfills can cause environmental and social problems. Therefore, reinforcing landfills is an important issue. In this regard, Redwood landfill is located in Californ...

This paper presents results of numerical analyses for the seismic response of slope type topographies in an elastic medium, under vertically incident SV and P seismic waves by Boundary Element Method (BEM). Due to the complexity of this matter, few studies have been performed in this field. In this regard, a 2-D scattering and diffraction of plane...

Nowadays, the influence of the site and geological conditions, especially in the sedimentary basins, is quite obvious on the characteristics of the input motion and the distribution of their damage. The existence of various effective factors in calculating the seismic response of sedimentary basins such as topography features and the characteristic...

The experience obtained from recent earthquakes have indicated the influence of sites' stiffness on the surface seismic ground response. Stiffness of soil can be improving by different methods; the inclusion piles is one of them. In this regard the role of geometry parameter of the inclusion piles can be significant. This paper studies the effect o...

Pore pressure build-up and occurrence of liquefaction phenomena during earthquakes can create two effects including amplification of incoming waves and thus soil subsidence (damage to structures) or attenuation of the seismic motion. It is well known that considering the presence of liquefiable soil layer and pore water pressure induced by it could...

The experience obtained from recent earthquakes has indicated the influence of local geologic conditions on the significant characteristics of strong ground motion including amplitude and frequency content. In this regard, the role of material properties of alluvial layers and the topography of the site can be significant. This paper studies the ef...

امروزه ضمن توسعه صنعت راه و ساختمان و رشد پروژ ههای عمرانی )از جمله ساختمان سازی، سد سازی، تون لسازی، راه سازی و غیره( نیاز به یافتن بستر خاکی مناسب و یا ارتقای کیفیت بسترهای خاکی مسال هدار ب همنظور ساخت و ساز، افزایش یافته است. بستر خاکی به منزله ریشه، پایه و اساس ساختمان م یباشد و وجود نقصان در این بستر، پروژ ههای عمرانی را با خطر جدی مواجه م ینم...

پنجمین دوره‌ مسابقات ملی دیوار خاک مسلح (ژئووال)، به همت انجمن ژئوتکنیک ایران و میزبانی دانشگاه صنعتی شریف در اردیبهشت 1398 برگزار گردید. این مسابقات هر سال با میزبانی یکی از دانشگاه های کشور و توسط انجمن ژئوتکنیک ایران برگزار می‌ شود و فرصتی است تا شرکت کنندگان در قالب گروه ‌های دانشجویی در یک مسابقه علمی- اجرایی رقابت کنند. در این رویداد مسابقه د...

T‌h‌e p‌h‌e‌n‌o‌m‌e‌n‌o‌n o‌f n‌e‌g‌a‌t‌i‌v‌e s‌k‌i‌n f‌r‌i‌c‌t‌i‌o‌n (N‌S‌F) i‌s a f‌r‌i‌c‌t‌i‌o‌n f‌o‌r‌c‌e d‌o‌w‌n‌w‌a‌r‌d o‌n t‌h‌e p‌i‌l‌e s‌u‌r‌f‌a‌c‌e w‌h‌i‌c‌h o‌c‌c‌u‌r‌s a‌s a r‌e‌s‌u‌l‌t o‌f t‌h‌e s‌e‌t‌t‌l‌e‌m‌e‌n‌t o‌f t‌h‌e s‌u‌r‌r‌o‌u‌n‌d‌i‌n‌g s‌o‌i‌l a‌n‌d c‌a‌u‌s‌e‌s e‌x‌t‌r‌a l‌o‌a‌d o‌n t‌h‌e p‌i‌l‌e. H‌e‌n‌c‌e, b‌e‌a‌r‌i‌n‌g c‌...

امروزه استفاده از پی های عمیق و یا شمع های درجاریز بتنی، از رایج ترین روش های مورد استفاده جهت جلوگیری از نشست های کوتاه مدت و بلند مدت در ساخت سازه های سنگین و دارای اهمیت واقع در خشکی و دریا می باشد. تعداد و مشخصات ابعادی این شمع ها با توجه به عواملی همچون: مشخصات سازه مورد نظر، وضعیت لایه های خاک در محل احداث سازه، درجه اهمیت بنا، نیروهای وارد ب...

Generally, topographic effects are mostly introduced by hills, canyons, basins, and slopes. Besides, the topographic features produce significant seismic site effects and can apply a crucial influence on the severity of building damages and its spatial distribution during earthquakes. Some experience observation such as Tarzana hill in the 1994 Nor...

The construction of structures in order to evaluation of the seismic behavior of structures induced by subsurface tunnels and seismic interaction between them by Shaking Table tests and Numerical simulations.

Nowadays, in developing countries, due to city expansion and demand for trips within the city, creating the necessary infrastructures, such as an underground transportation network, is of great importance. But, constructing subterranean structures and underground tunnels carry a high- risk potential due to its surface seismic responses above which...

In his paper, back-analysis using results from instrumentation by finite element software for design of preloading method by embankment with prefabricated vertical drains (PVDs) was used, and the results were compared with each other. Hence, the basic geotechnical parameters obtained by laboratory and field experiments have been modified using this...

This paper presents results of a site-specific probabilistic seismic hazard analysis for northern part of the Qeshm Island, one the most seismic prone areas of Iran. Seismotectonic and seismicity properties of seismic sources in the study area were characterized and used for evaluation of various strong ground motion parameters implementing the cla...

This paper deals with the evaluation of two-dimensional site-effects due to the seismic interaction between hills with various configurations and underground cavities. The time-domain boundary element method is used to evaluate the site-effects of hill-cavity interaction subjected to vertically propagating in-plane SV and P waves. The presence of a...

Fragility curves are recently adopted and implemented in some geotechnical structures, mainly for waterfront structures to evaluate the seismic vulnerability of them. However, the vulnerability of broken-back block quay walls, as an efficient waterfront system in the areas with high seismicity, has not been evaluated. Therefore, in this study, a nu...

Breakwaters provide a calm sea basin for ships and protect harbor facilities by reflecting wave energy towards the open sea area. Their performance under environmental loadings is the main concern for coastal engineers. Liquefaction susceptibility of loose sediments of seabed threatens performance of these structures. The paper investigates soil li...

Development of civil engineering science has introduced tunneling as an important option in reducing the traffic volume of urban environments. Digging tunnels, in every depth, causes changes in the surface ground structure; tunneling in urban areas, especially when has passed through the residential areas has its own particular importance; there...

Due to the population growth and transportation problems in urban areas, the use of underground structures such as subways and tunnels are widely increasing in developing countries and populous cities. The passage of tunnels and subways under existing buildings reveals the important impact of these underground structures on the ground seismic respo...

In this paper, several pile load tests are conducted for the evaluation of the actual axial compressive bearing capacity of bored piles casted beneath rear crane beams in Shahid Rajaee Port Complex Development Project (SRPCDP) in south of Iran (case study). Different methods of pile load test interpretations are employed to achieve the actual beari...

Nowadays, it is evident that the seismic behavior of topographic features is may differ from free-field motion during earthquakes. Moreover, the technical literature has shown that 2D site effects caused by cavities and topographical functions as separately can considerably impact on the seismic response of the ground surface. Accordingly, it is ne...

Due to the increasing importance of geomorphologic conditions on the seismic ground response, in this paper the details about the effect of liquefiable soils on seismic ground surface response are discussed. At first, the equivalent linear analysis based on total stress model in the frequency domain are carried out and then the nonlinear analysis b...

Due to the complexity of scattering issues by topographical features above subterranean cavities, few studies have been conducted in this field. In this regard, a 2-D scattering and diffraction of in-plane P and SV waves induced by a U-shaped canyon above underground cavities is proposed herein to account for the topographic effect of such a canyon...

In order to improve subsurface soft saturated clayey layers under the oil storage tanks in Mahshahr project, the preloading method by embankment along with prefabricated vertical drains (PVD) with a triangular pattern has been used. To control performance of the embankments, some instruments such as Settlement Plates and Piezometers installed throu...

Nowadays, it is highly conspicuous that the problems of urban transportation are failed to be resolved on the ground thus the best and quickest remedy is using underground facilities in metropolises. Especially in congested urban areas, shallow depth underground structures (tunnels, subways and metro stations) are frequently built. Besides, the geo...

In this paper, the results of a comprehensive numerical parametric study on the seismic response of the half-plane with subsurface cavity have been presented. For analysis purposes, a numerical time-domain analysis is performed by utilizing a robust numerical algorithm based on time-domain boundary element method. It is observed that an embedded ca...

In this paper, stress behavior of shallow tunnels under simultaneous non-uniform surface traction and symmetric gravity loading was studied using a direct boundary element method (BEM). The existing full-plane elastostatic fundamental solutions to displacement and stress fields were used and implemented in a developed algorithm. The cross-section o...

Two-dimensional site effects caused by cavities under topographical functions can considerably impact the seismic reaction of the ground surface. Due to the complexity of scattering issues by topographical features above subterranean cavity, few studies have been done in this field. In the present study, the seismic response of semi sine-shaped can...

Liquefaction phenomena may cause two major concerns: 1- Ground deformation or ground failure due to the excess pore water pressure, and 2- Changing in ground site response caused by softening of liquefiable soil. Liquefaction assessment and its consequences have been investigated by many researchers. Although, there are not enough studies to deter...

Dynamic compaction (DC) technique with tamping is one of the soil improvement methods. Nowadays, there is a considerable interest in DC due to its advantages among the methods of soil improvement. In the present study, fuzzy logic and Sugeno inference system have been used to evaluate the influence of parameters involved in dynamic compaction over...

The experiences of past earthquakes disclosed considerable effects of underground holes like natural karstic cavities on the seismic ground response. On the other hand, due to the structures such as bridges and dams majority are located in the canyon shaped topographic features, it is essential to study the seismic interaction between them. In this...

Complex interactions between piles in a pile group together with the interactions between the piles and the surrounding soil, cause difficulties in the analysis of the behavior of a pile group. One of the neglected problems so far, is the problem of tapered pile group under lateral loading. The purpose of this study is to compare lateral bearing ca...

In this paper, the one-dimensional ground response of a near-fault earthquake is compared by two methods. An equivalent linear method based on total stress modeling in frequency domain and a nonlinear method based on effective stress modeling in time domain. DEEPSOIL.V5 software is used based on the latest achievements and various techniques in bot...

Nowadays, with development of transportation industry, underground tunnels have a vital role in urban communities. Thus, the need of tunnel construction is inevitable. In this study, using the boundary elements method (BEM) based on full-plane elastostatics fundamental solutions, behavior of shallow tunnels under both gravity loads and tractions ha...

Under-reamed (Belled) piles are useful methods to increase the bearing capacity in deep foundations. They have some enlarged bases in their stems. They are suited for soils which are often subjected to considerable ground movements due to seasonal moisture variations. Also group arrangement is an effective parameter in application of these piles. I...

In this study, the performance of underreamed piles in clayey soils has been evaluated. Underreamed piles are deep in-situ concrete piles with one or more enlargements in their stems. The enlargement is called bulb and increases the strength and stability of these piles. The goal of this study was comparing the performance of half-bulb and full-...

In this paper, an advanced formulation of a time-domain two-dimensional boundary element method (BEM) is presented and applied to calculate the response of a buried, unlined, and infinitely long cylindrical cavity with a circular cross-section subjected to SV and P waves. The applicability and efficiency of the algorithm are verified with frequency...

Dynamic analysis of earth embankments is even now a matter of concern among geotechnical engineers due to the difficulties exist in the appropriate selection of analysis method, constitutive model, and material properties. The LNG port, that is currently being constructed at the northern bank of the Persian Gulf at Tombak, involves an "L" shaped (t...

The present paper deals with the protection design of intake seawater pipeline that will be constructed in the LNG Project. In this study by using of limit equilibrium approach, the geometry of the protection layer with the viewpoint of holding capacity of drag anchors in cohesionless soils is estimated. All technical and executive points regarding...

This paper offers clarifications for two inconsistencies in lateral earth pressure calculations. First problem is the inconsistency of the methodology of seismic lateral earth pressure calculation for soils based on Mononobe-Okabe for Undrained Unconsolidated condition of clayey soils. The solution of this problem is described based on an analyt...

This paper presents an application of performance based design for Shahid Rajaee main container quay wall and anchor wall from both pseudo-static and dynamic analysis perspectives. In the beginning, the site of the project is described as well as its geotechnical condition. Presenting the main assumptions for pseudo-static analysis based on perform...

This case history presents an application of Dynamic Compaction of the soil layers susceptible to liquefaction behind the main container quay wall of Shahid Rajaee Port Complex Development (SRPCD), situated on shores of Persian Golf near Bandar-Abbas. The liquefaction of such layers during earthquake results in the great lateral earth pressure as w...

This paper focuses on the preliminary results of an extensive 2D parametric study of time domain site response analysis for high frequency input motion. Such study in which direct boundary element used as numerical tool evaluates the effects of such motion on seismic behavior characteristics of various homogenous shapes surface topographies (semi-e...

This paper presents the results of an extensive numerical parametric study on the seismic behavior of two-dimensional homogenous semi-elliptical, semi-sine, and trapezoidal shaped hills subjected to vertically propagating incident SV wave. The medium is assumed to behave as a linear elastic constitutive material. All computations are executed in ti...

This case history presents an application of Dynamic Compaction of the soil layers susceptible to liquefaction behind the main container quay wall of Shahid Rajaee Port Complex Development (SRPCD), situated on shores of Persian Golf near Bandar-Abbas. The liquefaction of such layers during earthquake results in the great lateral earth pressure as w...