Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis The Modified Vlasov Foundation on Nonlinear Soil Layers(01. Izmir Institute of Technology, 2021) Çerezci, Mehmet; İşbuğa, Volkan; İşbuğa, Volkan; İşbuğa, Volkan; 03.03. Department of Civil Engineering; 01. Izmir Institute of Technology; 03. Faculty of EngineeringIn this thesis, a novel approach to account for the soil nonlinearity of nonhomogeneous soil deposits by employing the modified Vlasov foundation model is developed. A new algorithm that takes the modulus degradation curves at varying strain levels into account in an iterative manner is obtained by modifying the previously developed formulation. The presented model will provide researchers with the opportunity to employ the experimental test data directly for an operational strain level that may occur in many foundation engineering designs. This new model which takes the nonlinear soil behavior into account is first verified against the linear model given in the literature to ensure that the new model algorithm can capture the linear solution when the soil behavior is assumed to be linear. Later, the experimental data of modulus reduction curves reported in the literature for a specific type of dense and loose sands are used in multiple foundation deflection analyses. Example problems are considered for different cases which presented: (i) how the model captures nonlinear behavior and (ii) the significant effect of the nonlinear soil behavior on deflection, moment, and shear force. The model results are also compared with the finite element model result, assuming a bilinear stress-strain soil model. The results obtained from both models matched well, especially for the maximum deflection values that occurred in the example problems.Master Thesis Impact of Urbanization on Hydrogeodynamic Systems: a Case Study: Bornova Region (i̇zmir, Turkey)(01. Izmir Institute of Technology, 2021) İşbuğa, Volkan; Öztürk, Bahadır; Baba, Alper; Baba, Alper; İşbuğa, Volkan; 03.03. Department of Civil Engineering; 01. Izmir Institute of Technology; 03. Faculty of EngineeringUrbanization is one of the most critical processes affecting land and water use. Understanding urbanization and its impact on ground systems gained prominence with global climate change and population increase. This study focuses on the new city center Bornova Plain, İzmir; Turkey, used as agricultural land until the 1950s. Later, the region was opened for settlement, and excessive urbanization decreased the hydraulic conductivity of the surface area of the plain with the constructed buildings, road pavements, and other surface coverings. Effects of the land use- land cover changes on the hydrodynamic system of Bornova Plain's aquifers were investigated in three parts. Firstly, GIS-based hydrological models with two different periods (2004 and 2020) scenarios were developed with ArcSWAT for this thesis. Using SWAT models, elements of the water budget equation were determined. With SWAT Models, Recharge/Precipitation, Streamflow/Precipitation, and Baseflow/Total flow ratios were found to decrease 52%, 26.09%, and 11.86%, respectively, and Surface Runoff/Total Flow, and ET/Precipitation ratios were found to increase 20.59%, and 15.09% with urbanization increment comparing 2004 and 2020. Secondly, soil's bearing capacity changes with groundwater level changes within a year were investigated using five observation wells. Conceptual models were created for each well. Maximum of 14.82% of bearing capacity change was observed in the wells. Thirdly, PLAXIS 3D models were created to understand the effect of the groundwater level changes on pile settlements for sandy and clayey soils in the region. Conceptual models created and maximum of 12.74% settlement difference was observed for different groundwater levels.