Behzad Fatahi

Behzad Fatahi
University of Technology Sydney | UTS · School of Civil and Environmental Engineering

PhD, MEng, BEng (hons)

About

229
Publications
108,868
Reads
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3,592
Citations
Introduction
Dr. Fatahi has worked as a consulting and site geotechnical and railway engineer (e.g. Coffey, and SES) and has completed doctorate studies in Soft Soil Geomechanics from the University of Wollongong in Australia. Dr. Fatahi was named 'Australasia Young Railway Engineer of Year 2007' by Engineers Australia and Railway Technical Society of Australasia.
Additional affiliations
January 2008 - January 2017
University of Technology Sydney
Position
  • Professor (Associate)
July 2003 - July 2007
University of Wollongong
Position
  • Research Assistant

Publications

Publications (229)
Article
An emerging real-time ground compaction and quality control, known as intelligent compaction (IC), has been applied for efficiently optimising the full-area compaction. Although IC technology can provide real-time assessment of uniformity of the compacted area, accurate determination of the soil stiffness required for quality control and design rem...
Article
Soil is a cross anisotropic particulate medium with different strengths in various directions; this is primarily due to its geological deposition process and the very fact that particles always settle in their most stable positions. This study examines the influence of inherent anisotropy on the ultimate bearing capacity of eccentrically and obliqu...
Article
Full-text available
Assessment of seismic resilience of critical infrastructure such as liquefied natural gas (LNG) storage tanks, is essential to ensure availability and security of services during and after occurrence of large earthquakes. In many projects, it is preferred to build energy storage facilities in coastal areas for the ease of sea transportation, where...
Article
Full-text available
Liquefied natural gas (LNG) is cleaner and cheaper for power generation than traditional energy sources. Many tanks that store LNG are located in coastal areas with less favorable geotechnical conditions and often in seismically active regions. The seismic loads acting on LNG tanks are highly affected by the soil–foundation–structure interaction (S...
Article
The rocking pile foundation system is a relatively new design concept that can be implemented in bridges to improve their seismic performance. This type of foundation prevents plastic damage at the bridge piers and the foundation system, which are difficult to repair and can lead to collapse. However, lack of adequate energy dissipation in this typ...
Article
Low embankment strategy is one of the effective methods to control time-dependent settlement of soft soils in infrastructure construction projects. Spatial variability of soil characteristics is a crucial factor, affecting the reliability of predictions of the long-term settlement in soft soils. In this paper, the time-dependent behaviour of soft s...
Article
In order to obtain a better understanding of the load transfer mechanism of open-ended tubular piles driven into weak rocks, numerical analysis is conducted to study the internal and external shaft frictions, base resistance and the stress distribution pattern in the surrounding rock mass. Meanwhile, since pile shoes are often applied when driving...
Article
The present study provides an insight into the effect of recycled carpet fibre on the mechanical response of clean sand as backfill material subjected to monotonic loading and cyclic loading as well as post-liquefaction resistance of both unreinforced and carpet fibre reinforced soils. To achieve these goals, a series of multi-stage soil element te...
Chapter
Use of intelligent compaction (IC) is a growing technique for compaction in the field of construction. It provides an efficient way of evaluating the soil compaction level with a higher degree of certainty than traditional quality control methods. IC involves the interpretation of measured values received through the accelerometer and other sensors...
Chapter
Intelligent compaction (IC) is an emerging technology for efficient and optimized ground compaction. IC combines the roller-integrated measurements with the Global Positioning System (GPS), which performs the real-time quality control and assurance during the compaction work. Indeed, IC technology is proven to be capable of providing a detailed con...
Article
The re-liquefaction resistance of cemented sands under multiple liquefaction events such as pre-shock, main-shock and after-shock earthquakes is a complex phenomenon because the response may alter due to bond breakage. A series of multi-stage liquefaction-reconsolidation soil element tests under undrained stress-controlled cyclic loading condition...
Article
Scrap tyres are a significant source of pollution and pose a grave threat to the environment and human health. The present study aims to examine the application of Tyre Derived Aggregate (TDA) in a concrete slab track and ballasted track and compare its performance in both track forms. In this study, long-term performance of slab track and ballaste...
Article
This paper proposes an analytical solution in terms of Green’s function formulations for axisymmetric consolidation of a stone column improved soft soil deposit subjected to time-dependent loading under free strain condition. The mathematical derivations incorporate the pore water flows in radial and vertical directions in stone column and soft soi...
Article
An elastic visco-plastic creep model was combined with the Monte-Carlo probabilistic method incorporating multivariate copula and nonlinear analysis to investigate the effects of uncertainties in the elastic visco-plastic model parameters on time-dependent settlement and the distribution of excess pore water pressure in soft soils under applied loa...
Chapter
Rigid piles are used to alleviate the detrimental characteristics of soft soil. Recently, the use of piled embankments has increased by many folds, as it facilitates rapid construction without compromising on serviceability. In the piled embankment, soil arching mechanism between adjacent piles improves the load-transfer to the piles and reduces th...
Chapter
This paper presents the effect of burial depth on the response of conventional buried pipelines under strike-slip fault rupture and also proposes a mitigation method using geofoam blocks to safeguard buried pipelines. The performance of the buried pipelines is assessed using three-dimensional numerical simulation using ABAQUS. The configuration of...
Chapter
This paper provides an analytical solution to predict the free strain consolidation of a stone column supported soft soil under plane strain configuration. The external load on the ground surface was assumed to be applied instantly, which results in time-independent but space-dependent total stresses in the composite ground. A rigorous analytical s...
Chapter
This paper presents the interaction mechanism of a 12-story building sitting on a piled raft foundation with a strike-slip fault rupture. The mechanical response of foundation including both structural and geotechnical response of the foundation are evaluated through three-dimensional numerical modelling using ABAQUS. The obtained results showed th...
Article
Generally numerical modelling can provide an accurate and cost-effective approach to understand the behaviour of geosynthetic-reinforced column-supported embankment. When the problem geometry cannot be simplified to the two-dimensional plane-strain or axisymmetric, a full three-dimensional solution is required to obtain sensible results. This study...
Article
In the present study, the interaction mechanism of a 10-story moment-resisting building frame sitting on the conventional piled raft foundation with a strike-slip fault rupture with a dip angle of 90̊ is studied via three-dimensional finite element numerical simulation using ABAQUS. In addition, an alternative composite foundation system with geosy...
Article
This study aims to investigate the influence of cementation on the stress-strain and strength characteristics of soil during cavity expansion in lightly cemented sand deposit using three-dimensional discrete element simulations. Contact models, simulating the cementation effects of bonded clumps and capturing the interlocking effects between discre...
Conference Paper
Full-text available
Concrete liquid storage tanks are commonly used in regions that may be highly seismic, for the storage of water, petroleum products and other chemicals. In some cases, such as for liquefied natural gas (LNG) tanks, a secondary concrete containment is designed for external protection, ignoring any direct contact or interaction with the inner storage...
Article
The construction of railway embankment on soft soil is a challenging task for practitioners. In the past, several approaches have been employed in practice to overcome this problem. Pile foundation is considered one of the reliable solutions for soft ground. In a pile-supported railway embankment, soil arching plays a vital role in the efficient lo...
Article
Full-text available
In this study, a weight-control bender element system has been developed to investigate the impact of matric suction equalisation on the measurement of small strain shear modulus (Gmax), during an air-drying process. The setup employed is capable of measuring the shear wave velocity and the corresponding Gmax of the soil sample in either an open sy...
Article
For a foundation to perform safely, the ultimate strength of each pile must satisfy the structural and geotechnical requirements. Pile load testing is considered to be a direct method for determining the ultimate geotechnical capacity of piles. In this paper the dynamic and static response of a driven steel pipe pile monitored as part of a highway...
Article
This paper provides an analytical solution for consolidation problem of a stone column-improved soft soil layer subjected to an instantly applied loading under free strain condition. The radial and vertical consolidation equations are solved in a coupled fashion for both the stone column and its surrounding soil. A general solution of excess pore w...
Article
Buildings constructed adjacent to the slope crest in seismically active areas might be exposed to serious danger when they are subjected to strong earthquake excitations. The ground conditions can influence the seismic response of structures through a phenomenon known as the slope-foundation-structure interaction. Indeed, the presence of the slope...
Article
This study seeks to assess the influence of choice of initial cavity radius on the soil response during cavity expansion in sandy soil adopting three-dimensional discrete element simulations and obtaining the size of the influence zone when the expansion starts from zero initial radius. Sandy soil is modelled adopting rolling resistance contact mod...
Article
Pile foundations are widely used to support offshore wind turbines due to their cost effectiveness and rapid constructions. Offshore piles must be designed with enough capacity to withstand overturning moments caused by wind turbines and other environmental factors such as wave excitations and extreme winds. In this study, a full-scale field experi...
Article
This paper proposes using geofoam blocks to improve the safety of buried steel pipelines under permanent ground deformation due to strike-slip fault rupture. Since these geofoam blocks are deformable, they can compress during fault rupture and thus reduce the pressure imposed on the pipeline by the surrounding soil. This means that the pipe can sus...
Conference Paper
Full-text available
Rocking is a form of base isolation that can be adopted in bridge foundations to reduce the overall seismic demand on a structure. By allowing the foundation to uplift under severe earthquake loading, inelastic behaviour that would typically occur at the piers is significantly reduced and as a result, a safer structure is achieved. However, reducti...
Chapter
The presence of soft soil located along the coastal belt of Australia poses a serious challenge to the construction of infrastructure projects. The pile-supported embankments provide a viable alternative to deal with such problematic soil. The soil arching mechanism plays a key role in transferring loads to piles in an efficient manner. In this stu...
Conference Paper
Full-text available
Rocking pile foundations is a new design approach used in bridges that enables both the structure and foundation to remain elastic during intense earthquakes. However , this system offers less energy dissipation than conventional rocking foundation designs, and hence the dynamic response is expected to be larger. Moreover, the soil medium could inc...
Article
According to the characteristics of the time-dependent dispersion coefficient of pollutant migration in soils, a one-dimensional pollutant migration model considering solute decay is established in the finite thickness soil. Based on the proposed model, the time-dependent boundary condition variable is considered, and different types of time-depend...
Article
This study focuses on the internal shaft friction of open-ended tubular piles induced by jointed weak rock plugs. To investigate the bearing mechanism of the plug, push-up load tests were carried out on the jointed mudstone inside a tubular pile. The discrete-element method (DEM) was used in order to consider heterogeneity and to reproduce the disc...
Article
Full-text available
Tire derived aggregates have recently been in wide use both in industry and engineering applications depending on the size and the application sought. Five different contents of tire derived aggregates (TDA) were mixed with sand thoroughly to ensure homogeneity. A series of large scale oedometer experiments were conducted to investigate the compres...
Article
In this study, a numerical investigation into how the shear wave velocity profile affects the seismic performance of tall buildings and foundations was carried out using FLAC3D software. The in situ soil profile and equivalent average soil profile, which reflect the actual soil shear wave velocity profile and the corresponding uniform time-averaged...
Conference Paper
Full-text available
Ground surface motion induced by the upward propagating seismic waves could cause severe damage to structures on ground surface. The propagation of seismic wave could be significantly affected by the presence of joints embedded in a rock mass. The joints could attenuate and slow down the travelling wave. Moreover, the multiple wave reflections occu...
Chapter
Full-text available
The reuse of whey waste, a by-product of the dairy industry, is an emerging issue due to the environmental impacts. Some previous experimental studies have indicated that whey waste can be used as an admixture for cement-based materials, including mortar and concrete, to reduce the setting time and increase the workability, thus reduce the amount o...
Conference Paper
Full-text available
In this study, the effects of incident angle and joint depth on the ground surface motion induced by the shear wave propagation across the rock mass were numerically assessed. A three-dimensional coupled discrete element-finite difference model consisting of a 40-m deep rock mass with a single joint, was developed using 3DEC software. The continuou...
Conference Paper
Full-text available
Seismic soil-structure interaction is referred to the process wherein the soil dynamic response is influenced by the structure motion whilst the latter is also affected by the soil motion. To assess the seismic response of the soil-structure systems, selecting the appropriate soil model parameters is of great importance and the predictions can be s...
Article
An external restraining system which is anchoring the bridge superstructure to the embankment backfill is proposed in this study for the seismic protection of isolated bridges. The restraining system is employed to reduce the seismic demands of the bridge deck by utilising the otherwise inactive ground behind the abutment back-walls. The system can...
Article
Full-text available
The small strain shear modulus (G max) is an important parameter in geodynamic problems. To predict the G max of unsaturated soils that are normally subjected to complex drying and wetting processes, the effect of hydraulic hysteresis needs to be evaluated. Although several equations have been proposed in recent years, limitations still exist, requ...
Article
Full-text available
In congested cities such as Sydney, competition for underground space escalates within the built environment because various assets require finite geotechnical strength and support. Specific problems such as damage to buildings may develop when high-rise buildings on piled foundations are subject to ground movements as tunnels are constructed. This...
Article
The current study investigated the extent to which the choice of the soil constitutive models can impact the predicted seismic performance of a 20-story reinforced concrete moment-resisting building with a mat foundation considering the Seismic Soil-Structure Interaction (SSSI). Since the soil, in general, is the weakest material, involved in the c...
Article
Post-liquefaction response of lightly cemented sands during an earthquake may change and become similar to uncemented sands due to bonding breakage. In the current study, the effect of degree of cementation on liquefaction and post-liquefaction behaviour of lightly cemented sands was studied through a series of cyclic and monotonic triaxial tests....
Article
This paper focuses on the deformation of soils considering the time-dependent stress-strain evolution. In this paper, a new mixed hardening hyper-viscoplasticity model is proposed for the derivation of the time-dependent constitutive behaviour of soils, with the intention to capture the variation in the shapes of the yield loci by pursuing non-asso...
Article
Plate anchors are generally used for structures like transmission towers, mooring systems etc. where the uplift and lateral forces are expected to be predominant. The capacity of anchor plate can be increased by the use of geosynthetics without altering the size of plates. Numerical simulations have been carried out on three different sizes of squa...
Article
Full-text available
Article
Soil arching effect results from the non-uniform stiffness in a geosynthetic-reinforced and column-supported embankment system. However, most theoretical models ignore the impact of modulus difference on the calculation of load transfer. In this study, a generalized mathematical model is presented to investigate the soil arching effect, with consid...
Article
Full-text available
In this study the spatial variability of soils is substantiated physically and numerically by using random field theory. Heterogeneous samples are fabricated by combining nine homogeneous soil clusters that are assumed to be elements of an adopted random field. Homogeneous soils are prepared by mixing different percentages of kaolin and bentonite a...
Chapter
Full-text available
Discrete element method (DEM) is gaining its popularity in investigating many complicated geotechnical related problems due to its discontinuous nature in simulating granular materials. Particularly when simulating the processes involving large deformation and displacement of soil (e.g. pile penetration), DEM demonstrates distinct advantages over o...
Chapter
Full-text available
In this paper weak rock specimens with different individual fracture lengths are numerically simulated using the discrete element method (DEM). Effects of micro or macro-mechanical responses of intact and fractured specimens subjected to triaxial test have been studied. Various individual fracture lengths with a given fracture density within the we...
Chapter
Diversity of construction methods is available for the installation of piles; and generally piles are classified into two main groups in terms of their installation method, including non-displacement piles and displacement piles. However, non-displacement piles such as bored piles or drilled shafts cause less disruption to adjacent soil compared to...
Article
Geosynthetics have been used in variety of geotechnical engineering projects, such as ground improvement, erosion control, slope stabilisation and foundation strength improvement and they have been proved to be cost and time effective in many cases. In this study, a geosynthetic reinforced composite soil (GRCS) foundation system is proposed for sei...
Article
Soil displacement induced when installing controlled modulus columns (CMC) as ground reinforcement could affect the columns installed close by. Realising numerical analyses may provide useful insights, this paper describes a numerical approach to investigate how groups of CMC installed in different sequences could affect columns installed previousl...
Article
In this study, a cushioned pile foundation reinforced with geosynthetics is proposed to protect buildings and foundations from seismic energy. This composite foundation utilises piles to control foundation settlement while the geosynthetic-reinforced cushion modifies the dynamic structural characteristics and the load transfer mechanism. The seismi...
Article
Recent earthquake events have shown that besides the earthquake forces, interaction between the fault rupture and structure could cause a lot of damage to the surface and underground structures. Field observations have revealed a need to design structures for fault induced loading in regions with active faults. In this present study, three-dimensio...
Article
Full-text available
The discrete element method (DEM) has been extensively adopted to investigate many complex geotechnical related problems due to its capability to incorporate the discontinuous nature of granular materials. In particular, when simulating large deformations or distortion of soil (e.g. cavity expansion), DEM can be very effective as other numerical so...
Article
This paper proposes closed‐form analytical solutions to the axisymmetric consolidation of an unsaturated soil stratum using the equal strain hypothesis. Following the 1‐dimensional (1D) consolidation theory for unsaturated soil mechanics, polar governing equations describing the air and water flows are first presented on the basis of Fick's law and...
Conference Paper
Full-text available
In this study, the seismic response of mid-rise buildings supported by end-bearing pile foundations under the influence of six different soil Plasticity Indices (PI) is investigated. FLAC3D is utilised to develop the soil-pile-structure system and perform fully nonlinear analysis in time domain adopting the direct method. The results in terms of sh...
Conference Paper
Full-text available
This paper presents an experimental investigation on the enhancement of swelling behaviour and soil water characteristic curve (SWCC) of bagasse fibre and lime stabilised expansive soil. Lime stabilisation is commonly used to improve the engineering properties of expansive soil. Bagasse fibre, an industrial waste by-product left after crushing of s...
Conference Paper
Full-text available
The Seismic Soil-Structure Interaction (SSSI), which is a tangled phenomenon, is concerned with the shear waves in preference to the longitudinal waves on account of a prevalent greater energy content in the former. The need for the high rise buildings in the megalopolises results in the paramountcy of the seismic soil-foundation-building interacti...
Conference Paper
Full-text available
Mid-rise buildings supported by different configurations of end-bearing pile foundations can fulfil the design requirements addressed in the modern building codes and selecting the most efficient configuration is a challenging task. In this study, the influence of group configuration (but keep the area replacement ratio constant) on the seismic res...
Article
Several experimental studies have demonstrated that temperature changes may significantly influence the deformation of unsatu-rated soils. Thus, there is an essential need to develop a predictive framework for unsaturated consolidation capturing the nonisothermal effect. This paper presents an analytical solution to the one-dimensional (1D) consoli...
Article
The importance of using materials cost effectively to enhance the strength and reduce the cost, and weight of earth fill materials in geotechnical engineering led researchers to seek for modifying the soil properties by adding proper additives. Lightweight fill materials made of soil, binder, water, and Expanded polystyrene (EPS) beads are increasi...
Article
Seismic pounding occurs when the separation gap between buildings and structures is not wide enough, particularly during major earthquake events; this can cause them to collide, causing local damage or, in extreme cases, collapse. This study investigated the impact that this separation gap has on the seismic response of midrise buildings supported...
Article
This study proposes to use fractional derivatives to evaluate the long term performance of circular mat foundations overlying clays and also predict the associated ground settlement. Closed form solutions for the deflection and bending moment of foundations and the subsequent reaction of subgrade are obtained with the Mittag–Leffler function. Numer...
Conference Paper
Diversity of construction methods is available for the installation of piles; and generally piles are classified into two main groups in terms of their installation method, including non-displacement piles and displacement piles. However, non-displacement piles such as bored piles or drilled shafts cause less disruption to adjacent soil compared to...