In the last 30 years, many studies have been done concerning the stability analysis of SOIL structures and determination of their deformations. Finite ELEMENT method, is a powerful tool for investigation in this field. Elasto- perfectly-plastic constitutive law and associated flow rule, along with finite ELEMENT method are utilized for calculating the safety factor of SOIL slopes. Several failure criteria have been presented. In this paper, nine failure criteria are used for stability analysis of SOIL structures. The results are compared with Bishop Method.

This study proposes a new formulation for modeling SOIL-structure interaction (SSI) problems. In this direct time-domain method, the half-space SOIL medium is modeled by spectral ELEMENT method (SEM) which is based upon a conforming mesh of two-dimensional quadrilaterals, and the structural frame components are modeled by finite ELEMENT method (FEM). Formulation and various computational aspects of the proposed hybrid approach are thoroughly discussed. To the authors' knowledge, this is the first study of a hybrid SE/FE method for SSI analyses. The accuracy and efficiency of the method is discussed by developing a two-dimensional SSI analysis program and comparing results obtained from the proposed hybrid SE/FE method with those reported in the literature. For this purpose, a number of SOIL-structure interaction and wave propagation problems, subjected to various externally applied transient loadings or seismic wave excitations, are presented using the proposed approach. Each problem is successfully modeled using a small number of degrees of freedom in comparison with other numerical methods. The present results agree very well with the analytical solutions as well the results from other numerical methods.

It has been more than a decade since mesh-free methods gained considerable attention in engineering and science. The main distinction of the methods with respect to the FEM is their shape functions. In this regard, Diffuse ELEMENT Method (DEM) employs Least-Squares (LS) approximation, while ELEMENT-Free Galerkin Method (EFGM) benefits from Moving-Least-Squares (MLS) approximation for shape function construction. In order to compare the results of the methods, Boussinesq problem, which has closed-form solution, is used as a benchmark. The results are compared in displacement and stress fields. Finally, it is concluded that EFGM error is less than DEM in the both fields. This is more pronounced in stress field due to weight function being constant in DEM.

Starting from two-dimensional (2D) equations of motion, discretized formulations for transient behavior of SOIL-structure interaction problems have been derived. Two different dynamic infinite ELEMENTs taking into account single and two-wave types are presented in transformed space. By coupling the infinite ELEMENTs with standard finite ELEMENTs, an ordinary finite ELEMENT procedure is used for simulation of wave propagation in an unbounded foundation due to external forces.

Throughout the present study, a simulation of tire–SOIL interaction model was considered with special view at the two-Dimensional (2-D) Finite ELEMENT Method (FEM) model of carcass. In contrast with the existing 2-D tire models, in the new model it was not tried to find a mathematical description for the global reaction of tires, but was based on a mechanical structure of the basic components of a tire. Here, the reproduction of the carcass as the most challenging part for a 2-D model was described in details. Also, the reproductions of tire wall model as a hyperelastic material and SOIL model as an elastopelastic one were investigated. Coefficients of mechanical behavior of silty-loam SOIL were accurately assessed to obtain an effective simulation. The results of simulation implemented in MATLAB7 Software, showed that the radial-ply tire benefitted from a greater tractive efficiency than the bias one within the same conditions on silty-loam SOIL. Bias-ply tires suffered from a greater motion reduction (slip) and while their gross traction was slightly greater than that of radial-ply tire. The net traction force was estimated as the same for both tires. Also, the results of simulation and tests revealed that the radial-ply tire bore lower rolling resistance than bias-ply tire on silty-loam SOIL in similar conditions. Based upon the simulation results, the effects of slip, inflation pressure and mechanical stiffness of SOIL on tractive efficiency were satisfactorily predicted.

The environment prevalent in ocean necessitates the piles supporting offshore structures to be designed against lateral cyclic loading initiated by wave action. Such quasi-static load reversal induces deterioration in the strength and stiffness of the SOIL-pile system introducing progressive reduction in the bearing capacity associated with increased settlement of the pile foundation. To understand the effect of lateral cyclic load on axial response of single pile in soft clay, a numerical model has been developed. The theoretical results are compared with the available experimental results so as to validate the theory. This paper presents a brief description of the methodology developed, analysis and interpretations of the theoretical results obtained and the relevant conclusions drawn there from.

In recent decades, the use of an efficient and cost-effective method to provide SOIL stability has been a major challenge for civil engineers. With the increasing urban population, the need for underground spaces increases, and deep excavation is an inevitable affair in civil projects. Deep tunnels and large buildings require deep excavations, which must use some techniques to stabilize it. SOIL-nailing (reinforcing SOIL at the site) due to the fast build, is a good way to provide stability. It can also be described as a top-down construction technique for the improvement of the behavioral properties of the in-situ SOIL mass. The SOIL-nailed system is formed by inserting relatively slender reinforcing bars into the slope. Depending upon the project cost, site accessibility, availability of working space, and the SOIL and groundwater conditions, SOIL-nails can be inserted into the ground. SOIL-nail is generally known as conventional and injectable nails but nails with screw plates or "helical SOIL-nails" are also important due to the faster build and no need for groutings. Helical SOIL-nails are a new alternative to the conventional SOIL nails or tie-backs for stabilization of slopes, excavations, and embankments due to ease of installation, minimal site disturbance, and immediate loading capability. Helical SOIL-nails are installed by application of torque without a drill hole and derive its capacity from one or more helical plates attached to the nail. The shear strength-displacement behavior at the interface is an important parameter in the design of various geotechnical engineering projects, for example, SOIL-nails, retaining walls, shallow foundations, pile foundations, etc. In SOIL-nailing, the behavior of the interface between the SOIL and nail estimated by the pull-out test. The behavior of interface is governed by numerous factors, such as stress conditions, SOIL properties, method of installation, and SOIL-nail interface boundary conditions. The pull-out resistance is measured as the most important factor in the design of the nailing system, by the pull-out test. This study, because of limited learning of helical SOIL nail, aimed to investigate the pull-out resistance by a 3D finite ELEMENT modeling with Abaqus software and compare its results with laboratory data. A review of the literature for the screw SOIL-nails, as well as a comparison of its performance with conventional SOIL nails, are discussed and numerical results of a series of pull-out tests on a screw SOIL-nail are presented. And a review of the overburden pressure and plate number and plate distance effect is followed. The results show that in helical SOIL-nail pull-out a high overburden pressure effect can be seen. A linear relationship between peak pull-out force and overburden pressure is observed for different methods of calculating the helical SOIL-nail capacity that it is indicating that it follow the Mohr-Coulomb failure criteria. Rupture surfaces occur at distances farther than the nail surface, and three times the diameter can be considered the optimal distance of the plates. Using fewer plate distances does not increase resistance, also using more plates with fewer distances does not increase resistance. A comparison of modeling and laboratory results indicates that modeling of the pull-out test can model the behavior of helical SOIL-nail and verify its performance in a field SOIL slope.

Today the important of studying SOIL effect on behavior of SOIL contacted structures such as foundations, piles, retaining wall and other similar structures is so much that neglecting of SOIL-structure interaction effect can cause to untrue results. In this paper SOIL-structure interaction simulation was done by using Finite ELEMENT method analysis with ABAQUS version 6.13-14. The results have been presented based on pile function in contact with SOIL, vertical stresses in SOIL and structures, pore pressure in drained and undrained condition and underground water level. Final conclusions revealed that pore pressure effect is not uniform on all parts of pile and amount of pore pressure increment in top ELEMENTs is lower than down ELEMENTs of pile. Finally, it was concluded that 70% of pile bearing capacity is depend on friction of SOIL and pile contact surface.