The comparative analysis of geological, geophysical and geotechnical methods in soil research and improvements

In this study 50 pieces of ground survey datas which belong to Adapazarı region have been used. Generally Adapazarı plain occured from alluvium sediments. Region is a first degree of earthquake zone. This region located on the North Anatolian Fault Zone. Because of this there are many seismic activities. Grounds of all regions are very weak. One of the very important parameter which is indicator of weak grounds is low level of underground water. Groundwaters are located in the very near points of surface. İn this study fifty pieces of ground drillings and seismic datas have been evaluated. Especially groundwater levels have been found in the very near point where there are foundations of structures. The lowest level of groundwater is one meter. The highest level of groundwater is three meter below the surface. According to seismic measurements; Shear waves velocities are between 100-130 m/sn in 3-10 meters deep of grounds. But shear waves velocities are less than 200 m/sn in the other dephts. According to drilling studies; the values of SPTN30 are less than 10 in the first parts which are closer the surface. These low values indicate the weakness of grounds. According to MASW studies; Shear wave velocities which have been measured from surface to 10 meter are very low level in all area of Adapazarı plain. According to low level VS velocities, low level SPTN30 values and low level Plastic limits values; the region's grounds are very weak. During the earthqake, liqefaction can be occured inside of the ground's layers. This situation can cause of the structure's destructions. The liqefaction causes a ground consolidation. The methods of soil improvements, depending on the ground problems must be applied in the region. The soil strengths are found as weak in this region according to datas obtained by geological, geophysical and geotechnical studies. The Alluvium soils which are composed of clay, silt and sand have low strength. The soils of the region investigated in this study have very variable and complex parts which have different rate of the components at short distances. İn conclusion; complex type of the grounds which have different rate of components and grain size distributions in short distance doesn't allow to occur strong correlation values within different methods Keywords: Ground surveys, Drilling, SPT, Seismic Waves, ,MASW