Abstract
Seismic refraction survey is conducted for geotechnical evaluation to the soil of Tikrit university at allocated site to construct a new building for housing the professors of the university . The measurements of compressionnal and shear waves velocities are conducted along six profiles at the study area . Four main layers were recognized from the results of the seismic data interpretation . Depending on the (Vs/Vp) ratio, three geotechnical properties were calculated for geotechnical evaluation to the different layers, these are Poisson's ratio(σ), Material index (Im) ,Plasticity index (P.i). The contour maps for different layers are plotted to show the distribution of geotechnical properties at the study area. These maps are divided into two zones, Zone A represents the area which has good geotechnical properties ,and Zone B represents the area which has weak geotechnical properties such as loose unconsolidated sediments or weak zones. The results of evaluation show that the first and third layers are fairly competent to intermediate competent layers because they have good geotechnical properties by comparing with second and fourth layers which have poor geotechnical properties which represent incompetent layers. Depending on the values of plasticity index , the sediments of the study area ranges between low plasticity to intermediate plasticity sediments except some of the places characterized by high values of plasticity index representing high plasticity sediments.