NEAR SURFACE CHARACTARIZATION FOR FOUNDATION STUDIES USING SEISMIC REFRACTION METHOD AT POST GRADUATE HOSTEL, FUPRE.

ABSTRACT The study was carried out at the Post Gradute Hostel at Federal University of Petroleum Resources to determine the near surface charactarization studies for foundation building using seismic refraction method to know the subsurface strength and suitability. Seismic refraction survey was conducted for data acquisition. Three traverses were used for the data acquisition. The data was acquired using a 24-channel geophone (PASI-GEA 24) and was processed using the GEO-STRU software. A total of three geologic layers were identified along the fifteen traverse each having density of 1800kg/m³, and poisson’s ratio of 0.35 for all the layers. Having a velocity range of approximately 220.5m/s – 371.7m/s for the first layer, the second layer has a velocity range of approximately 381.7m/s – 440.8m/s, and the last layer has a velocity range of approximately 902.1m/s – 1196.2m/s. The shear modulus for layer one and two range from 20mpa - 57mpa and 62mpa - 91mpa, respectively, which indicate that they are composed of silty sand. Layer three's shear modulus indicates that it is formed of dense sand with a shear modulus range of 338mpa – 594.38mpa. The first layer young's modulus ranges from around 54.53mpa – 154.98mpa for all the traverses which suggests loose sand, the second layer young's modulus also range from163.40mpa – 246.56mpa suggest sandy clay as the main material, and the third layer young's modulus ranges from about 912mpa – 1604.81mpa suggests dense sand.