This research has been achieved with the purpose of morphotectonic studies of the Sufian-Shabestar fault zone in the West Alborz-Azerbaijan (NW Iran). The fault zone cuts the Neogene and Quaternary units in south of the Misho Mountains. The maximum of horizontal and vertical displacements along the Sufian-Shabestar fault zone are H=2500±200 m in Meshnaq river and V=66±4 m in fan east of Benis village, respectively. The minimum of horizontal and vertical displacements along this fault are H=9±0/5 m in offset stream of N Sharafkhaneh city and V=6±4 m in river NW of Kozehkanan city, respectively, all estimated based on combining data of Digital Elevation Model in scale of 1/25000, aerial photographs in scale of 1/20000, LANDSAT ETM satellite imagery and field studies. The estimated rate of horizontal and vertical displacements are H=135±20 m V=19±4 m in NW of Sharafkhaneh city, respectively and all allow us to estimate the rake of fault by geometry calculations. Based on estimate, the rake of the Shabestar fault segment is 11±4W. The Sufian-Shabestar fault zone is a right lateral-reverse strike slip fault with strike N81E and rake range of between 04, 11 with westwards dip, all estimated based on the rake of fault plane and morphotectonic data. Therefore, the Sufian-Shabestar fault zone (including faults segments of Sufian, Shabestar, F1, Sharafkhaneh (F2) and F3) is neotectonically an active zone.

Failures caused by surface rupture in recent earthquakes emphasize the need to investigate fault-structurefoundation interaction while designing engineering structures and life lines in fault zones. Many civil projects, especially buildings on problematic soils (e.g. loose soils with low carrying capacity, high settleability and liquefaction, made grounds, and others), use micropiles in the sub-base to improve the soil and increase its carrying capacity. If such structures are positioned in fault zones, however, the interaction between the faulting and the micropiles located at the faulting zone is often neglected. Therefore, this paper used numerical modeling in Abacus to investigate the reverse fault-micropile interaction, and modeled and analyzed the three-dimensional soil, foundation and micropile system using the finite element method in Abacus. In this regard, a footing with an 11m length and width and a 91 kPa load (equivalent to a 9-floor building) was modeled atop a 15m-thick sandy soil layer. S set of 36 concrete micropiles with 20cm diameter, 10m length and 2m distance to each other were also used for investigating the base-fault-micropile interaction. The numerical analysis was validated using laboratory results. The ratio of the distance between the faulting and sub-base contact to base width (S/B) was the most important criterion used in this study, and the parametric study investigated the effect of the micropile foundation’s location relative to faulting after selecting the S/B parameter. Results show that the foundation and micropile response depends on their position relative to the fault, and responses to deviation or rupture propagation around the structure differ by structure position. The overall results show that the presence of micropiles does not significantly affect horizontal displacement control, resulting in a 10- 15% reduction in horizontal displacement compared to the no-micropile state for S/B>1.0. Micropiles are consistently effective for controlling vertical foundation displacement and reduce vertical displacement by about 60% compared to the non-micropile state. This is caused by the faulting’s contact with the micropile-foundation block, which makes it act as a retaining wall and leads to rupture diffraction, distribution, and diversion. However, results differ by foundation rotation in different conditions. Due to the residual stress between micropile rows in 0.9<S/B<1.5, the faulting-micropile interaction increases the foundation rotation in the micropile state by approximately 40% compared to the non-micropile state, that points to the inefficiency of micropiles in controlling foundation rotation when put in such a condition. Therefore, if the objective, importance, limitations and other criteria affecting engineering structure placement call for a mixed “foundation and micropile” structure adjacent to the fault, the position of the foundation with the micropile set relative to the faulting is a determinant factor of soil-faulting-micropile and foundation interaction results. Accordingly, investigating horizontal and vertical displacement as well as foundation rotation with S/B ratio changes can determine the optimal structure position relative to the fault and fault path and prevent damages.

Utilizing of fiberglass nail in the face of tunnel is one of the economical and effective pre-support methods for increasing stability and control of settlement in weak grounds and tunnels with extended level and increase of ground mechanical strength. In this study, by taking advantage of 3D modeling of fiberglass nail which is effective in reduction of deformation, settlement, the direct modeling of nail in the 3D finite element and material with equivalent section. This study has covered effects of nail density, the overburden to depth of tunnel ratio. The method of strength reduction for analyzing the safety factor of tunnel has been considered. The result of 3D numerical analysis with limit equilibrium methods (LEM) for determining safety factor has been compared. The comparison of LEM and finite element method revealed that using of nail fiberglass and increases the range of safety factor between 5% to 75% and 1.25 to 2 in terms of overburden to diameter ratio. This increase of nail is dependent on density and overburden. While, with increase to advance length, the amount of vertical displacement would rise in both method, although these measures have no effects in horizontal displacement. In addition to that, using of nail in the tunnel face has caused the amount of vertical displacement between 20 to 35 percent and in the horizontal displacement between 50 to 60 percent of decrease has happened.

The advancement of technology with an increasing population has led to the requirement for high-speed mobility trains. High-speed transportation by trains requires passing through soft soil conditions, which requires stability. High-speed trains are used nowadays in developed countries to reduce travel time. When the train moves at a critical speed, it can significantly increase the dynamic responses of the components on the railway lines. The present study examines the results of 3D numerical modeling, considering the impact of the high-speed train passing through the mechanical earth wall stabilized by plate anchors. Numerical modeling was carried out using Plaxis 3D finite element software. The impact of various factors such as the speed of the train (180, 200 & 250 Km/h), the number of plates (single, double, and triple), and the number of train tracks (1 & 2 tracks) have been investigated. The Hardening soil with small strain model has been used for modeling the behavior of the backfill soil. In this study, the geometrical characteristics of the Thalys high-speed train were used to model the train passing through the walls of 6 meters that were stabilized with plate anchors. From the results, it was concluded that Increasing train speed from 160 to 250 Km/h increases the settlement under the rails by 11% and increases the horizontal displacement of the wall by 13%. It was confirmed that increasing train speed will result in an increase in the settlement under the rails and increases the horizontal displacement of the wall in all investigated cases. Increasing the number of plates along with decreasing their dimensions has a positive effect on the wall’s performance with regard to the horizontal displacement of the wall. Also, it should be mentioned that by increasing the number of train tracks from 1 to 2, the settlement under the rails increased by 5%, and the horizontal displacement of the wall increased by 20%.

The internal waves generation process and sound propagation mechanism have been studied, separately. However, the effects of internal waves on sound waves behaviour is a study field that has not received any attention in our country. Marine environments are generally density stratified continuously or step-like. Layered structure of oceans affect sound propagation. Taking into consideration that some Iranian waters are density stratified and also have some internal waves that can be used in a sound propagation process for many purposes, it is necessary to study internal waves and sound transmission interaction. This paper attempts to discuss the effects of internal waves on underwater sound propagation using a mathematical model and find out how these process are inter dependent. The parameters such as sound speed, buoyancy frequency, displacement variance, relative perturbations in sound propagation associated with vertical displacement and horizontal particle velocity, phase & amplitude function, internal waves phase & amplitude spectrum were computed using Caspian sea data. The parabolic approximation was applied in the wave equation to calculate amplitude spectrum density and phase fluctuations of a plane sound wave propagating through a random field of internal waves in the sea.The rate of sound propagation perturbations due to vertical displacement and particle horizontal velocity shows that horizontal displacement is much lower than vertical one.We found out that wave number and vertical displacement increase with increasing depth and decreasing buoyancy frequency. A maximum in buoyancy frequency and sound propagation fluctuations in associate with vertical displacement is observed near water surface which is due to thermocline and there is a minimum in vertical displacement at same place.

This paper discusses the effect of the horizontal movement of impinging jets on the convective heat transfer from a cylindrical concave surface. In this way, the averaged Navier-Stokes equations for turbulent incompressible flow in a steady state considering two prevalent turbulence models and a Low-Re model with the Yap correction in the 3D computational space were solved. Results indicate that the Yap correction significantly improves the over-prediction of Nusselt number in the impingement zone. The results show that the decrease in the distance of the center of the jets to the outlet edge of the concave surface leads to the transfer of the maximum amount of the Nusselt number to the upstream flow, and the approach of the main flow of the jet to the recirculation region formed in the upstream flow results in the increase in the turbulent kinetic energy of this area and the Nusselt number in the stagnation point.

Deep excavations in soft clayey soils usually cause excessive ground settlement and wall movements due to the creep in soft soils. One of the commonly used methods for predicting these displacements is numerical analysis, however, in most cases for modeling soft clayey soils, soil behavior is considered to be time-independent. So, the effect of excavation time and creeping in soft soils are ignored. In this paper, the impact of the time of construction of the excavation and creep effect that occurs in soft soils are studied using three case studies. These three excavations are stabilized using a combination of soil anchorage and soil nailing methods. For studying the time influence and creep effect in soft soils with numerical modeling, excavations are modeled using three different soil constitutive models, namely Mohr-Coulomb, Hardening Soil (HS), and Soft Soil Creep (SSC) models. The real field records by installed in-situ instruments are employed to evaluate the performance of three constitutive models for simulating the excavation wall behavior. The obtained results show that for realistic simulation of the behavior of deep excavations, the construction time and the corresponding creeping behavior should be included in the numerical modeling procedure in order to better match the numerical predictions with the time-independent behavior of soft soils.

Engineering and economic investigations in dam construction projects throughout the world indicate that, in many cases, rockfill dams with impervious clay cores are the best selection for the final design (Rezaei and Salehi, 2011). This approach makes the investigation of different issues affecting the stability of rockfill dams worthwhile. In general, dam safety is the first and foremost reason for controlling deformation and physical parameters in dams. Another reason is the importance of basic design concepts for engineers to apply in future designs as well as understanding the resistive and behavioral characteristics of soil and pebbles. One of the most effective approaches for interpreting the mechanical and hydraulic behavior of structures such as dams is to use data and compare the results with numerical modeling predictions. In the field of earth and rockfill dams, monitoring of typical physico-mechanical behaviors is a fundamental issue. Measurements of displacements, total stresses, pore water pressures, and arching ratio can be used to carry out a number of tasks (ICOLD, 1982), such as characterizing the dam’s overall behavior (Pagano et al., 1998), checking the behavior of specific zones, obtaining information about the in situ mechanical properties of embankment soils (Marsal and Resendiz, 1975), and finally, supporting the difficult task of evaluating dam safety and efficiency (Gould and Lacy, 1993). Justo (1991) and Naylor (1997) proposed methods for the incorporation of collapse settlement of rockfill into constitutive models. Naylor (1991) performed the finite element analysis for Beliche dam, a central core earth and rockfill dam, by considering the collapse settlement of the upstream rockfill in the modeling. The effect of pore water pressure dissipation in earthfill during construction was also considered by a number of authors including Eisenstein and Law (1977) and Cavounidis and Hoeg (1977), amongst others. For these cases, the incremental embankment construction was modeled as a two-stage process, the first stage modeling the new layer construction using undrained properties for the core and the second stage modeling pore water pressure dissipation. Zomorodian and Kuchi studied internal deformation, pore water pressure, and total vertical stresses in Masjed Soleiman Dam and compared it to numerical results, they also showed that the development of excess pore water pressure in the clay core of zoned earth dams during construction may lead to the onset or progression of hydraulic failure.

Demand for high-rise buildings and shopping malls has increased in recent years. For this reason, these buildings have a variety of basements. Due to insufficient land, some parts of these structures are being built underground. Stabilizing vertical cuts by emerging methods provides a new way for the construction industry. In addition, the demand for stabilizing vertical cuts on highways and railways against dynamic forces has been raised. There are various methods for stabilizing underground cuts. Soil nailing is one of the most common methods for stabilizing cut slopes in building industry. In this method, the soil is strengthened by placing the steel rods into the drilled holes on the wall and the ground. It is worth mentioning that, this method could be used for underground construction. Whereas soil nailing wall system needs less space in comparison with other retaining wall systems, in urban areas especially where walls cuts are surrounded by structures is more applicable. Observations of the performance of soil nails walls in recent earthquakes indicate that their destruction by deep excavations rarely occurs. Literature review on the soil nail walls shows that the mechanism of reinforcement and design of the soil nail walls is without considering of seismic loading. However, few studies have been performed on the seismic behavior of these walls. In this paper, the dynamic behavior of the steel soil nail walls has been investigated numerically. In order to validate two-dimensional, nonlinear finite difference model created by FLAC software, obtained results from the instrumental excavation wall (Hotel Narges No.2) were used. In this study, a numerical parametric study was performed to investigate the factors affecting the behavior of the soil nail wall system. This parametric study has the effect of wall height (3, 6 and 9 m), nail angle (10 and 15 degrees), soil properties (type 1 to 3 based on Iranian code of practice for seismic resistant design of building (2800)) and seismic loading characteristics such as magnitude, frequency of the maximum acceleration of the earth's surface were examined. In addition, four equivalent harmonic loads instead of 15 time history are used. After analyzing 72 different models, it was concluded that by decreasing the soil shear strength (types 1 to 3), the displacement of the upper edge of the wall would increase sharply, with the decrease of the nail angle (from 15 to 10) horizontal displacement of the upper edge wall reduced. By decreasing the angle of the nails (from 15 to 10), the force of the nails is increased. Increasing the height of the wall increases the horizontal displacement of the upper edge of the wall. Also by changing the type of harmonic loading type 1 to type 4, the behavior of the soil nail wall varies with soil type changes, which can be attributed to the effect of soil damping and soil type on the different seismic behavior of the nailed structures. The calculated dynamic analysis results show that the data are scattered under four different harmonic loads. Therefore, the seismic performance of the soil nail structures depends on the geometry parameters and the selection of the main mapping parameters including mold period, acceleration, and mapping duration is very important and requires sufficient accuracy. The dominant mode of deformation of the soil nail wall for four harmonic loads, and for all heights is around the intersection point of the wall and cavity.

Stone column installation method is one of the popular methods of ground improvement. Several studies have been performed to investigate the behavior of stone columns under vertical loads. However, limited research, mostly focused on numerical investigations, has been performed to evaluate the shear strength of soil reinforced with stone column. The stress concentration ratio (n) is one of the important parameters that uses in soil improvement by stone column method. Stress concentration ratio is the ratio of the stress carried by stone column to that carried by the surrounding soil. In this paper, the results of a laboratory study were used to examine the changes in the stress concentration ratio when normal and shear stress applied. Direct shear tests were carried out on specimens of sand bed material, stone column material and sand bed reinforced with stone column, using a direct shear device with in-plane dimensions of 305*305 mm and height of 152.4 mm. Experiments were performed under normal stresses of 55, 77 and 100 kPa. In this study, three different area replacement ratios (8.4%, 12%, 16.4%), and three different stone column arrangements (single, square and triangular) were considered for investigation. Loose sand and crushed gravel were used to make the bed and stone columns, respectively. In this study, the equivalent shear strength and equivalent shear parameters measured from experiments were also compared with those predicted by analytical relationships at stress concentration value of 1 and stress concentration value obtained from experiments.

Fine-grained sand with particle size ranging from 0.425 to 1.18 mm was used to prepare loose sand bed, and crushed gravel with particle size ranging from 2 to 8 mm was used as stone column material. The sand material used as bed material had a unit weight of 16 kN/m3 and a relative density of 32.5%, and the crushed stone material used in stone columns had a unit weight of 16.5 kN/m3 and a relative density of 80%. The required standard tests were performed to obtain the mechanical parameters of bed material and stone column material. As the diameters of model scale stone columns were smaller than the diameters of stone columns installed in the field, the particle dimensions of stone column material were reduced by an appropriate scale factor to allow an accurate simulation of stone columns behavior.

 In this study, large direct shear device was used to evaluate the shear strength and equivalent shear strength parameters of loose sand bed reinforced with stone column. Experiments were performed under normal stresses of 55, 75 and 100 kPa. Two class C load cells with capacity of 2 tons were used to measure and record vertical forces and the developed shear forces during the experiments, and a Linear Variable Differential Transformer (LVDT) was used to measure horizontal displacement. The main objectives of this study was to calculate the stress concentration ratio of stone columns in different arrangement. Stress concentration ratio is the ratio of the stress carried by stone column to that carried by the surrounding soil, and can be calculated using Equation 1. For this purpose, the direct shear device was modified. Two miniature load cells with capacity of 5 kN were employed. The load cells were mounted on the rigid loading plate with dimensions of 305*305 mm2 and thickness of 30 mm, as shown in Figure 1, All achieved data from the experiments including data on vertical forces, shear forces and horizontal displacements were collected and recorded using a data logger, and an especial software was used to transfer data between the computer and the direct shear device. All specimens were sheared under a horizontal displacement rate of 1 mm/min. Experiments were performed on single stone columns and group stone columns arranged in square and triangular patterns. The selected area replacement ratios were 8.4, 12 and 16.4% for single, square and triangular stone column arrangements. To eliminate boundary effects, the distance between stone columns and the inner walls of the shear box was kept as high as 42.5 mm. In total, 11 direct shear tests were carried out, including two tests on loose sand bed material and stone column material, and 9 tests on stone columns with different arrangements. From the tests performed on group stone columns, 3 tests were performed on single stone columns, 3 tests on stone columns with square arrangement and 3 tests on stone columns with triangular arrangement. Hollow pipes with wall thickness of 2 mm and inner diameters equal to stone column diameters were used to construct stone columns. To prepare the specimens, first, the hollow pipes were installed in the shear box according to the desired arrangement. Then, bed material with unit weight of 16.5 kN/m3 was placed and compacted in the box in 5 layers, each 3 cm thick. Stone material was uniformly compacted to construct stone columns with uniform unit weight.

The SCR value increases for settlement up to 3 mm and then decreases with increasing the horizontal displacement and then approaches almost a constant value. Results also show that stress concentration ratio decreases with increase of stone column diameter. Results show that the value of stress concentration ratio in square pattern is higher than that in single and triangular pattern. Moreover, results show that stress concentration ratio decreases with increase of normal stress. The value of the internal friction angle in (peak) state, for loose bed increases from 33 to 40 degrees in square arrangement and in the corresponding state of displacement of 10 % from 30 degrees in a loose bed increase to 32 degrees, for loose sand reinforced with stone column. Shear strength increases with the increase of modified area ratio in all stone column installation patterns in both the peak and the corresponding state of the horizontal displacement of 10%. For stone columns with the same modified area ratio, the installation pattern has an effective role in defining the shear strength. Group stone columns mobilize higher shear strength compared to single stone columns. Among the installation patterns investigated in this study, stone columns with square arrangement experienced the highest increase in shear strength value while single stone columns experienced the lowest. The equivalent shear strength values measured from experiments are higher than those obtained from analytical relationships. Accordingly, it is conservative to use analytical relationships to calculate shear strength parameters. It is worth explaining that these relationships assume that the value of stress concentration ratio is equal to 1. Results from this study show that the value of stress concentration ratio should be accurately calculated and used in the relationships. Comparison between shear strength parameters obtained from experiments and those predicted by analytical relationships shows that in single stone columns, the value of stress concentration ratio should be 3 to 4.5, and in square and triangular patterns, this value should be 6 to 7 and in triangular patterns 4.5 to 5, respectively, to achieve good agreement between experimental and analytical results in peak condition. In horizontal displacement 10% the value of stress concentration ratio should be 2.5 to 3, in single, square and triangular patterns, to achieve good agreement between experimental and analytical results../files/site1/files/151/2.pdf