This paper includes an analysis to asses the behavior of stone columns using the finite element method and to provide bases and information helping geotechnical engineers to design foundations resting on weak soils reinforced with stone column. The axisymmetric quadrilateral element is adopted in the finite element program to simulate the soft soil and the stone column while the one-dimensional element is used to simulate the soft soil and the stone column-soil interface. The nonlinear inelastic stress-dependent model is used to simulate the behavior of the soil and the interface throughout the incremental loading stages adopting nonlinear parameters obtained from triaxial and direct shear stress. The analysis is carried first on a selected basic problem, to clarify the nonlinear of the column, in which a selected geometry, boundary condition, and material properties for both soil and interface as chosen. The rest of the analysis is grouped into the effect of some of the parameters concerning the geometry of the stone column and the material of column and adjacent soil are investigated. It was found that the increase in stone column length and in relative stiffness of stone column material to soil play an important role in increasing ultimate capacity of the stone column and in reducing settlements.
Abstracte: The stress-strain behavior of any type of soil depends on a number of different factors including density, water content, structure, drainage conditions, strain conditions (i.e., plane strain, triaxial), duration of loading, stress history, confining pressure, and shear stress. In many cases it may be possible to take account of these factors by selecting soil specimens and testing conditions which simulate the corresponding field condition. Even when this can be done accurately, however, it is commonly found that the soil behavior over a wide range of stresses is nonlinear, in elastic, and dependent upon the magnitude of the confining pressure employed in the tests. In order to perform stress analysis of soils, it is desirable to employ techniques, which account for these important aspects of soil behavior.
This research aims to study sediment discharges in Al Anbar Thermal Power Station in two phases the first phases include a follow-up study sediment load from the river by taking samples at different depths and different discharges, and noted measurements, calculations for each section while the second phases included an account of the tonnage of river sediment through the program depends on the equation of Meyer, to five sections (18, 26, 35.43, 45) with the observation results and do a comparison between the two phases. Research has included also employ technology of remote sensing and geographic information system GIS in the study of the waters of the Euphrates at thermal power plant after an analytical study was taken amount sediment and size in the study area and then link results with the geographic information system GIS for the purpose of producing layers represent the nature of the spatial distribution of these Sediments on the entire study area and the aerial imagery of software Google Earth with the use of the program (Arc view), one of the geographic information system software. The research concluded give recommendations for controlling the movement of sediment when the at Al Anbar Thermal Power Station Outlet through two main axes of them increase the flow velocity exceeds the critical velocity and the other includes the disposal of sediments away from the site of the station outlet.