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Most of the research has been concentrated on the effects of the horizontal components of near-field earthquakes on the dynamic behavior of the embankment dams. In this paper, the effects of the vertical components will be considered. One of the important characteristics of the near-field ground motions, is the noticeable vertical component with the high frequency content that can exceed considerably, in many cases, the horizontal component of the same earthquake. So far, few studies have been done in this area. In order to investigate the effect of the vertical ground motion on the dynamic behavior of embankment dams, a two dimensional numerical model of the Alborz dam is analyzed by using finite difference method which is used in FLAC2D code. It should be noted that the Alborz dam is a rockfill type with clay core and a maximum height of 78 m located on the Babol River in the north of Iran. The Mohr Coulomb elastic perfectly plastic constitutive model was used to simulate the stress-strain behavior of the dam body and its foundation during the static and dynamic loading. Steps of modeling are as follow: At first stage, construction was carried out in 16 layers. At this step, coupling analysis were done in order to simulate the consolidation and build up of pore pressure in clayey core, with respect to the real time of construction for each layer. Then the analyses were continued to modeling of the impounding. So at this stage the reservoir was raised to the normal water level and the model were analyzed to the steady state seepage condition. Records of near-field and far-field were selected from the same earthquake to provide better and more accurate comparison. Before applying the earthquake records to the base of the foundation in the model, they must be modified. So deconvolution analyses were done by using SHAKE2000 code in order to get the target motion with peak ground acceleration of 0.52g at the surface of the foundation (maximum credible earthquake level at the site of Alborz dam). In addition filtering process, baseline correction and conversion the acceleration time history to the stress time history were done. Results of analysis show that the vertical component of near-field ground motion has considerable effect on the magnitude of strains and deformations including: increasing the settlement of the dam crest to about 45 percent, increasing the deformation of the horizontal axis of the dam, reduction of the magnification factor of the dam crest and especially in the case of near-fault, which the occurrence of near-field earthquakes is more probable. Therefore, this issue should be considered in locating the embankment dams regarding the seismic potential and the distance from the fault, and in the design of them.

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Simultaneous Heat and Water Model (SHAW) is based on the assimilation rate of melting and/or freezing of the accumulated snow as well as melting of ice in soil. The main objective of this study was to evaluate applicability of SHAW Model in determining maximum depth of frost penetration in soils in some typical climates of Iran. To this end, the daily data of air temperature, soil temperatures at different depths, duration of bright sunshine, and air humidity were collected for the period of 1992-2003 for four meteorological stations of Iran including Shahr-e- Kord, Urumia, Sanandaj, and Yazd. Then, the maximum soil frost penetration depth (SFPD) for each year in the above mentioned stations was determined based on both the measured temperatures at different layers of soil and the calculated values using SHAW Model. Results of the analyses indicated that there was a significant linear relationship between the observed and the calculated values of maximum SFPD. The obtained coefficients of linear correlation between the observed and the calculated values for meteorological stations of Shahr-e-Kord, Urumia, Sanandaj and Yazd were 0.90, 0.77, 0.84 and 0.94, respectively, all being significant at one percent level. According to the results, it was concluded that, with the yearly records of weather parameters and soil conditions, a reliable estimate of the maximum annual depth of soil frost penetration can be made in similar regions of Iran by application of SHAW Model.

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Anchors play a special role in geotechnical structures such as excavations. The anchor section in soil is generally divided into five zones including reinforcement element, grout, grout and surrounding soil mixture, shear zone and soil media. The main objective of the present research is to determine the soil-anchor interaction parameters for numerical modeling of anchored wall using FLAC2D software. Basically, the injection area determining is the main challenge in the anchor force nomination. According to the proposed method, the diameter of the injected area is determined based on the injection pressure, grout volume, porosity and shear zone thickness. It is shown that the diameter of the injected area is approximately increased by 40% relatively to the drilling diameter. The diameter of the injected area in rock media, however, is equal to the drilling diameter. The other parameters are determined using equalization of rock media formulas for soil media. In order to ensure the validity of the proposed method, the pull-out test is numerically simulated in FLAC2D software. The numerical results have been then verified with anchor tension results in an excavation project. The results indicate that ultimate load of anchor calculated from the numerical model is comparable with equations proposed by many researches. Also, there is a negligible difference between the displacement obtained in numerical simulation and pull-out test results. This method is therefore can be used in numerical modeling of anchored wall in soil media with high precision. Anchors play a special role in geotechnical structures such as excavations. The anchor section in soil is generally divided into five zones including reinforcement element, grout, grout and surrounding soil mixture, shear zone and soil media. The main objective of the present research is to determine the soil-anchor interaction parameters for numerical modeling of anchored wall using FLAC2D software. Basically, the injection area determining is the main challenge in the anchor force nomination. According to the proposed method, the diameter of the injected area is determined based on the injection pressure, grout volume, porosity and shear zone thickness. It is shown that the diameter of the injected area is approximately increased by 40% relatively to the drilling diameter. The diameter of the injected area in rock media, however, is equal to the drilling diameter. The other parameters are determined using equalization of rock media formulas for soil media. In order to ensure the validity of the proposed method, the pull-out test is numerically simulated in FLAC2D software. The numerical results have been then verified with anchor tension results in an excavation project. The results indicate that ultimate load of anchor calculated from the numerical model is comparable with equations proposed by many researches. Also, there is a negligible difference between the displacement obtained in numerical simulation and pull-out test results. This method is therefore can be used in numerical modeling of anchored wall in soil media with high precision.

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Abstract: Saturated granular soils are possible liquefied when subjected to earthquake loading. This phenomenon is result from generation of excess water pore pressure because of non enough time to water drainage and govern non- Consolidated Condition. When liquefaction is occurred, many forces are generated and undergrounds structures are affected. In this research numerical analysis on buried pipelines in FLAC 2D software are performed and verified duration a comparative process with experimental result from ASCE organization. In present research surveyed effects of various parameters on liquefaction occurrence and probable damages to buried pipelines as dilatancy and friction angle of soil, relative density of back fill around the pipe, diameter and buried depth of pipe and underground water level. Results indicated that uplift of pipe decrease when dilatancy and friction angle of soil increased in constant relative density condition. This result is different for varied relative density. In low and medium relative density by increasing of dilatancy angle, uplift of pipe increase, reach to pick and decrease. But floating decrease with increasing dilatancy angle for high relative density always. Buried pipe in depth trench and increase of dead load result from back fill on pipeline and usage of pipes with small diameter, decrease uplift the pipe in liquefaction occurrence too. Of course don’t expect perform this subjects in all conditions. for example conflict ion to other underground installation, necessary hydraulic gradient for fluids flow or excavation in region with up underground level, don’t make to excavation of deep conduits. The analysis demonstrate that vertical displacement and damages to pipe is decrease if around installed pipe in conduit back fill with non- liquefied soils. In this new analysis all physical properties of soil and pipe in model are without any change except the cohesion and friction angle of soil around the pipe. Cohesion soils are low potential to liquefaction. For this reason we increase this coefficient from zero to 30 kpa and reach the friction angle to 30 degree. Results are demonstrated in a graph that show uplift versus thickness of non- liquefied soil normalized with diameter of pipe. Final parameter that surveyed in this research is effect of underground water level on floating buried pipeline. Results show decrease of underground water level cause to decrease of floating and damages to pipeline. For this purpose add a new water level to base model and run the analysis. In next steppes the underground water level is lesser and results are show in a graph that explain variation of vertical displacement versus water level normalized by thickness of soil model. This work possible by excavation of drainage shaft and drop down water level nearby the pipeline. Of course, look this work isn’t economical proposal for long transmission pipelines as petroleum or water conveyance. But in limit industrial sites as refineries this proposal is an improvement work to prevent any damage and and continual service of lifelines duration of unpredictable phenomenon. Keywords: Liquefaction, buried pipelines, FLAC, finite difference method, Finn’s model. Liquefaction, buried pipelines, FLAC, finite

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In this study, the hybrid Lattice Boltzmann - Finite difference - Immersed Boundary method has been used for investigation of problems with heat transfer. For this purpose, mass and momentum conservation equations are solved by the Immersed Boundary- Lattice Boltzmann method and finite difference method has been used for solving energy conservation equation. The effect of Immersed Boundary has been shown as force and external energy source term in equations and therefor flow and heat transfer around circular cylinder and also the effect of how to move cylinder in heating of fluid inside the cavity has been studied. for this purpose four kinds of movements: circular reciprocating, normal circular, diagonal amplitude and horizontal amplitude have been considered for the cylinder and in all cases, the changes of force coefficients and Nusselt number have been discussed. It has been showed that the circular reciprocating movement has more effect on heating of fluid inside the cavity, which indeed this movement reduces the time of fluid heating about 20 percent in comparison with normal circular and diagonal amplitude movement and approximately 37 percent in comparison with horizontal amplitude movement. In all of the studied problems, the efficiency of hybrid method has been proved.

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In this paper, a sandwich beam of a SMP material which have a corrugated core is studied. The corrugated core is from a polymeric material. Structures with corrugated profiles show higher stiffness-to-mass ratio in the transverse to corrugation direction compared to flat structures. As a result, the beam with corrugation along the transverse direction is stiffer than the one with corrugation along the beam length. The flexural behavior of the composite corrugated beam is studied employing a developed constitutive model for SMP and the Euler-Bernoulli beam theory. The constitutive model utilized is in integral form and is discretized employing finite difference scheme. To verify the results of the Euler-Bernoulli beam theory and finite difference method, finite element models of different corrugated sections have been simulated in a 3D finite element program. The results demonstrate that the developed model for the composite beam presented in this study predicts the behavior of the beam successfully. The sandwich beam with different corrugated cores (triangular, sinusoidal and trapezoidal shapes) are compared with each other. Also, results show that the shape fixity is decreased a little, like any other reinforcing method. This decrease in shape fixity results in increase of load capacity in composite beams. The stress-free strain recovery and constrained stress-recovery cycles are both studied.

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The soil formation consists of complex and longtime processes in which many different chemical and physical changes occur in soil deposit, or in its original source rock. This processes cause the soil to show nonhomogeneous characteristics and to have spatial variation in its mechanical properties. The spatial variation of soil properties lead to many uncertainties in prediction of soil mechanical behavior; subsequently the design of structure which depend on soil deposits becomes troublesome. For dealing with such problem the probabilistic and statistical tools are proposed as convenient methods for choosing appropriate design soil parameters and estimating the uncertainties in design. The coupled utilization of random field theory and Monte Carlo simulation technique yield probability distribution functions for geotechnical problems in which different cases of soil distribution is assumed for analyses. In such problems the soil properties are distributed into the field according to the assumptions of random field theory by consideration of a probability distribution (with the given mean and standard deviation) and scale of fluctuations. This distribution of soil properties with the use of random field theory is performed repeatedly until a desired statistical distribution for the results is obtained. This distribution can be used as a basis for extracting the statistical characteristics for the problem in hand. In this paper the effect of spatial variability parameters on the bearing capacity of strip foundations on clayey soils were investigated. The soil un-drained shear strength (Cu) was assumed as spatial variable parameter with the use of logarithmic distribution and the so-called coupled random field theory; the Monte Carlo simulation technique was used for obtaining probability distribution of bearing capacity of foundation on nonhomogeneous clayey soil. The Mohr Coloumb elastic perfectly plastic constitutive model and the Finite Difference Method (FDM) were used for modelling soil behavior and calculating the bearing capacity of foundation. The spatial variability of un-drained shear strength was investigated using three parameters: coefficient of variation of un-drained shear strength (Cov(Cu((, and the scale of fluctuation of shear strength in horizontal and vertical directions (x, and y directions). The range of these parameters were chosen such that the results of current research can be generalized to any field problem. The results obtained from this study, were investigated by average and coefficient of variation of NC parameter which is the cohesion factor in classic bearing capacity equations (i.e. as Terzaghi, Meyerhof, Hansen and Vesic bearing capacity equations). It can be interpreted from the results that by increasing the coefficient of variation of soil un-drained shear strength the average bearing capacity decreases and the coefficient of variation of bearing capacity increases; also the average bearing capacity of foundation has an approximately increasing trend with increasing the scale of fluctuations in both horizontal and vertical directions. Finally at the end of this paper two practical simplified equations were suggested using multiple regression method for estimation of average and coefficient of variation of bearing capacity factor NC, given the spatial variation parameters of soil un-drained shear strength. These equations can be implemented by geotechnical experts for applying the variability of cohesion in the design of foundations on nonhomogeneous clayey soil formations.

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Abstract

Wharf is an engineering structure which is constructed generally for loading or unloading of goods. The structure may be constructed on the weak layers like gravel and sand with respect to the bank conditions. In case of incorrect design of this type of structure and its failure, the wharf activities may be stopped for a long time due to damage to adjacent facilities. For this reason, investigating the behavior of coastal structures against failure factors such as earthquake and the liquefaction due to it, is of great importance. Analysis of wharf performance against liquefaction is done generally using the numerical methods. In this article using the Flac2D software which has the capability of nonlinear analysis of effective stress and generation of excess pore water pressure in the soil continuum, the liquefaction phenomenon in the soil surrounding the wharf is simulated using the behavioral model Finn. In continuation, the impact of different earthquake parameters on the wharf behavior is investigated. Finally, the results of the excess pore water pressure, horizontal displacement, soil settlement and bending moment of piles are presented. Then, the correlation between these parameters and different earthquake parameters is investigated. As the earthquake intensity criteria have great importance in terms of statistical assessment of seismic demand of various types of structures, therefore, in this study in order to investigate the quality of earthquake intensity criteria, the determining indices such as being optimal and applicable, efficiency index, sufficiency with respect to the earthquake magnitude and distance to the center of earthquake propagation are investigated. The results show that compatibility between the earthquake parameters and soil settlement is generally better with respect to other parameters.

Keywords: Wharf, liquefaction, dynamic analysis, finite difference method.