Properties of Diyarbakir basaltic clays and its effect on design parameters of geotechnical structures in different climatic scenarios

Diyarbakır province's mean rock formation is basaltic due to its location. Basaltic parent rocks release much silt or clay when imposed to chemical or physical weathering. The soils are residual in origin. In other words, they formed in situ where the basaltic parent rocks exist. They were not transported by means of wind or water. In this thesis, firstly, the properties of Diyarbakır basaltic clays were investigated from literature. After that one soil sample from Kayapınar vicinity has been taken to laboratory to find index properties. The values from two different locations which are obtained from literature and values which are obtained from laboratory were compared. The results indicated that the three samples from different locations showed roughly same index properties. As per results the clay is highly plasticity (CH) and it has swelling potential. In this thesis, design parameters of post tensioned slabs on ground under different climatic scenarios were found. The widely used method for slabs on ground under swelling soils is Post tensioning Institute (PTI) method. In order to use this method, Thornthwaite moisture index is required. This index is used in geotechnical engineering to identify moisture flux boundary conditions for unsaturated soils and depth of active zone for expansive soils. This index has been found using water balance sheet tables for Diyarbakır. So as to find the future moisture index, water balance sheet tables has been formed finding the climate projection data for Turkey in literature. In this way, five moisture index values of Diyarbakır has been found for current situation and with regard to RCP4,5 and RCP8.5 scenarios for 2050. The parameters em and ym , moments and shear force acting on slab for design procedure according to PTI method were found for each moisture index. Results showed that the ym and em values increased when the Thornthwaite moisture index is reduced. Also results showed that the slab thickness is increased when moisture index is reduced. It is also seen that the moments and the shear force also enhanced by the time dryness has increased. Considering the moisture index parameters for future values, Diyarbakır is likely to face arid climates in the future and the design parameters of geotechnical structures should be designed in accordance with the climatic variations.