Sharif Digital Repository

In previous studies, effect of certain parameters such as soil K0 on piled raft load sharing ratio α_pr was not considered. Here, α_pr is ratio of pile group load to total load. In this study, we consider the effect of pile length (L), pile spacing (s), raft thickness (t), raft modulus of elasticity (Er), pile modulus of elasticity (Ep), coefficient of lateral earth pressure, and pile concentration. Soil is undrained clay with typical properties. Raft is made of concrete and piles are cast in-place. Modeling is done in FLAC 3D. To determine the effect of these parameters we calculated load sharing ration of piled raft at 10 cm settlement which is typical for design. Based on the results of... 

Separation of the effects of the initial horizontal stress and relative density on the cone tip resistance in the sandy soils has been a complicated issue for many years. On the other hand, there is no reliable method for determining the in-situ horizontal effective stress based on the piezocone measurements in the cohesive soils, and the empirical correlations suggested in the literature produce no more than a rough estimation.Considering the aforesaid issues, an attempt is made in this thesis to provide a new innovative solution for determining the in-situ horizontal (effective) stress in the sandy and clayey soils according to the CPT measurements. In this regard, at first, numerical... 

Train-induced vibrations can disturb the residential areas close to the rail as well as making ground-borne noises that can create problems for sensitive apparatus and devices. To reduce these problems, there need to be an evaluation of the amplitude of the ground-borne vibrations. The goal in this study is creating a suitable finite difference model in order to predict the intensity of train induced vibrations propagating inside or on the surface of the soil using FLAC (Fast Lagrangian Analysis of Continua) software as well as assessing the effectiveness of recycled shredded tires in reducing the surface vibrations by using these material as the filler for vibration isolation trenches. The... 

Loess with a dispersion potential is one of the problematic soils of Iran. This study aims to investigate the impact of dispersion potential on the water flow in a three-phase medium and determine the effect of salinity on the stability of an unsaturated railway embankment by employing the soil-water retention curves of the materials. To satisfy this objective, the natural dispersive loess of the Chabahar region is desalinated in this study and the hydraulic properties of both saline and desalinated soils are comprehensively investigated. First, the soil-water retention curves of the materials are measured through the filter paper test method. Afterward, the saturated hydraulic conductivity... 

In-situ tests are strongly recommended in site investigations, since laboratory studies are not sufficient for precise determination of soil parameters. Effects of soil disturbance on laboratory studies questions the validation of obtained soil parameters. In the in-situ tests, soil experience less disturbance and these tests are conducted in stress levels resembling to soil initial horizontal and vertical stresses. Also more volume of soil is tested by in-situ tests in comparison to laboratory studies. Pressuremeter instrument was invented by Menard (1954). In this test, a flexible cylinder is expanded in the cavity under fluid pressure and the volume and stress changes of the cavity are... 

Cone Penetration Test (CPT) is one of the major in-situ tests used around the world. Obtaining undisturbed samples from sands is generally very difficult and expensive, and in some cases impractical. A good interpretation of CPT results can provide important soil parameters, and therefore the need for undisturbed sampling may be reduced. Using Calibration Chambers, a soil with predefined parameters is tested by cone penetrometer and some relationships are developed between CPT results and soil parameters. Using these relationships, in-situ results are interpreted. CPT results can be used to evaluate different aspects: soil stratification, geoenvironmental characteristics, stress state and... 

In recent years, growth of industries has led to consistent increase in energy consumption around the globe. On the other hand, non-renewable energy sources are the most consumed ones in the world. Therefore, governments and companies have tried to introduce budgets to facilitate the use of renewable energy sources and make their use cheaper. One of the renewable energy sources is geothermal energy which one economical way to havest it is thermal energy exchange between the building foundation and the ground. Therfore, thermal piles , by the use of a heat exchanger fluid, transfer the heat on the surface to the ground in warmer seasons and in cold seasons, they transfer the heat from the... 

The importance of rainfall pattern in assessing embankment stability and deformation is widely known. However, many studies have examined an embankment with simple rainfall patterns or used average and maximum ones. The importance of diverse rainfall patterns has also been overlooked in the study of divergent soil stability in the previous study. Therefore, the hydraulic properties of a natural soil with and without salinity potential and the stability analysis of the railway embankment located on this type of soil under various rainfall patterns are investigated. The study area is part of the Zahedan Chabahar National Railway Project, which is located on divergent soil and has high... 

The two-dimensional composites are benefited from different advantageous; however, they may not be good enough in terms of strength along the thickness, manufacturing speed, cost management and resistance to delamination. To overcome these unpleasant challenges, the three-dimensional composites are defined as having a 3D pattern of yarns which not only includes yarns along the length and width, but also in thickness or vertical direction. One of these common types of composites is 3D-orthogonal woven composites. In this comprehensive research study, the 3D orthogonal woven composite modelling is conducted through a specialized and advanced software, TexGen software. Then Voxel mesh were... 

The main purpose of designing machine foundation is to limit its motion to such an amount that not to prevent the perfect workability of machine, not to let the foundation strains exceed the elastic limit and also not to disturb the persons working around the machine. The key note in successfull design of machine foundation, is to precisely analyse the response of foundation to dynamic loads induced by machine operations.The numerical study of shallow foundations response to vertical harmonic loads induced by machinaries have been discussed in this investigation.To aim this purpose, FLACD3D has been utilized in order to 3 dimensionally analyse a continuum medium comprising soil-foundation or... 

This study aimed to model the cone penetration test using FLAC 2D software in order to investigate the silty soils that can be found in tailing dams. Additionally, the model of the direct simple shear test was built in the software to estimate the variation of liquefaction potential in these soils with in-situ conditions. It should be noted that the constitutive law used in this study was the NORSAND model which meets the requirements of modeling in both tests. After validating the models, several important parameters are considered as variables to examine their effects on the results of both experiments. Regarding the validation of the models, the constructed numerical models of the cone... 

Effect of utilizing Central Beam Column (CBC) structure on shallow, large span underground spaces excavation is studied. The CBC method focuses on increasing the overall rigidity of tunnel supporting system prior to full face excavation, in which central drift excavation is limited to the dimensions of the central beam and column to reduce disturbances. Constructing the central beam and column structure, the excavation is completed with NATM excavation method in a symmetric manner about centerline. In CBC method on each side of the centerline there is an arch structure composed of the initial lining resting on roof beam on top and bottom beam at the invert. The roof and bottom beams take the... 

Nowadays, pile usage in construction of deep foundations has increased significantly, instead of shallow foundation in areas that shallow foundations doesn’t provide enough bearing capacity and measuring the velocity and acceleration due to pile driving is very important. Because, all responses of building and individuals located near the pile driving site influenced by these three parameters: pile vertical displacement, peak particle acceleration (PPA) and peak particle velocity (PPV). One can estimates these important parameters by numerical analysis of pile driving process in different distances and depths to determining the effect of pile driving. Compared values obtained from numerical... 

In safe and economic designing of deep foundations for any structure, there are several factors affecting the behavior and response of a pile under seismic loads. These factors can be divided into three main categories: geometrical factors (e.g. Dimensions of the pile, soil, and mesh scheme), material properties (e.g. shear modulus, bulk modulus, soil elasticity, soil density, and shear strength) and earthquake load characteristics (e.g. frequency range, PGA, duration of excitation(. Studying the effects and importance of these factors in the final response of the pile (i.e. ultimate forces and displacements ) can help the design engineers of these foundations to optimize their designs.... 

Particulate porous mateials have always been of interest in terms of reducing shock waves effects in different protective applications. Therefore, the physics governing the flow in porous media is especially significant for which different models have been presented by the researchers. The complexities of these media have caused many existing models to be unable to properly predict the behavior of granular media under shock loadings. On the other hand, the complexity of the equations makes the numerical solution of them cumbersome and costly in a way that many researchers do not solve the whole coupled equations and reduce their number. In addition, current high-resolution TVD solutions of... 

This study highlights an important distinction between heat transfer mechanism in dry and saturated soil. Soil temperature data recorded during model tests, soil thermal response predicted using finite difference and analytical methods are compared with finite element models. In recent years, due to the industrial development of human societies, the energy consumption has been increased worldwide. On the other hand, the most commonly used energy resources are non-renewable energies. Therefore, governments and industries aimed to develop a technology which provides economical use of renewable energy sources. One of the renewable energy sources is the geothermal energy of the Earth. In this... 

In recent years, due to the development of cities and population growth, the number of underground floors and the depth of excavations have increased. Sustainability of excavation and control of deformation due to excavation process has always been considered as one of the important issues in geotechnical engineering. One of the most commonly used systems for deep excavation, especially in urban areas, is the soldier pile wall with tiebacks. This system consists of anchoring on soldier piles that are performed at horizontal distances around the excavation range. The cables have two parts. Unbond and bond length that, when pretensioned, have the task of transfering load out of the wedge of... 

Bearing capacity of piles depends on many factors among which geometrical properties of piles, soil type, and strength properties of soil are of great importance. Based on these parameters, several approaches have been developed in order to overcome the uncertainty in the prediction of pile bearing capacity. Studies carried out in this area or research can be divided into two main categories: first, laboratory based approaches, and second, numerically based approaches. The research followed in the present study is based on numerical modeling. In this study, a single pile is initially modeled in the axisymmetric configuration and its bearing capacity is determined. The results of the model... 

Bearing capacity of foundations is one of the most controversial issues in foundation engineering. In this study regarding to the previous researches which has done by the other researchers the bearing capacity factors of a footing has calculatedusing finite element method. On the next step of this study some footings has modeled on different positions near slopes with different angles and bearing capacity of them has calculated, then some strip foundation has modeled and bearing capacity of them has calculated and compared with the values of the footings in this study and strip foundations of the other researches. Furthermore some foundations have modeled on the solpe and bearing capacity... 

Numerous structures which are involved in seismic soil-pile-structure interaction have been destroyed. Considering complexities which exist in soil-pile interaction problems and lack of precise methods without imperfect bases, it is necessary to use numerical methods for analyzing soil-pile interaction problems. In this research, three-dimensional modeling and studying the effect of changing soil and pile parameters on the behavior of pile under earthquake loading is performed using finite difference software, FLAC3D. The soil in this model has a softening behavior. Real earthquake spectrum has been applied into the model as the acceleration time history at the bedrock level. The results of...