Geotechnical and statistical investigation of the relations between in-situ and laboratory tests of Van / Bardakçı region soils

The Bardakçı area and its surroundings located on the east of Lake Van, are composed of old lake sediments. Due to the level changes of Lake Van, lacustrine sediments were deposited with different thickness and grain sizes in this region. In this thesis, the field and laboratory studies were conducted on the clay levels in the study area and the relationships between field and laboratory data were examined. Two different boreholes that distance of 5 m were opened side by side at the same location and Standard Penetration Test (SPT) and Menard Pressuremeter Test (MPT) were performed. At the same time, disturbed and undisturbed (UD) clay samples were taken from these boreholes and the physical and mechanical properties of soil samples were determined in the laboratory. Linear and nonlinear regression analysis were conducted using the experimental data and the relationships among all data were investigated. High determination coefficients were obtained between Menard deformation modulus (EM) – pre-consolidation pressure (Ppc); EM – SPT-N60 and EM – cohesion (c). The results of multiple regression analysis revealed that the water content was the effective parameter on determining SPT-N60. Different EM, SPT, Ppc and c values were determined from same soil types, investigated in this study. The causes of such a finding was analyzed in this thesis and the compressive stresses due to the active Van Thrust Fault in this region was found to be more effective than vertical overburden and hydraulic water pressure on the mechanical properties of the soils.