Foundation design or the problematic soils with high groundwater level

In this work the examination on soil properties of the land includes the determination of the parameters of required materials for the design of the structure and all studies that were made to design the terrain were included. A number of difficulties are experienced during the foundation design andimplementation steps. The current underground water level being high causes so many problems such as the failure in carrying the loads put on or the liquefaction and liquefaction. With in the scope of the study, the foundation systems sitting on the soil profile which has the problematic of elevation of groundwater and compose the strata of silty sand, clayed sand, high plasticity sand, low plasticity silt, and high plasticity silt were modeled. For the combination that will be a basis to the features such as thekind of soil and underground water level in the problematic soil, the effects of thestres sand displacement situations in the foundation system were examined. With in the scope of the dissertation, for analysis of the ultimate bearing capacity and the settlement analysis, empirical calculation method sand PLAXIS 2D which is one of the computer software that works with finite element method were included. Numerous parameters that cannot be taken into consideration by traditional methods can be easily modeled with the help of software that uses finite elements and similar methods. In the calculation, the 22 x 50m raft foundation was vertically subjected to the self-weight of the foundation, the upper structure loads of six-floors structure, and 5.4 magnitude earthquake load. The foundation parameters used in the model has been changed and the foundation design was examined by the comparison between thestress that was obtained under the loading and the displacement value. In the analyzes conducted with raft and raft foundation models, smaller displacements are formed in raft foundation system compared to raft foundation. It has been observed that the ground parameters have significant effects on the load and the ground water level has adverse effects on soil properties. In addition, it is observed that the displacement values occurring in the earthquake effect on the high ground water level increased compared to the earthquake free condition.