SEISMIC REFRACTION SURVEY FOR FOUNDATION INVESTIGATION AT AHMADU BELLO UNIVERSITY ZARIA PHASE II, KADUNA STATE, NIGERIA
Abstract
Ahmadu Bello University Zaria Phase II was investigated for foundation purpose. Four shallow seismic refraction profiles were carried out using the ABEM Terraloc Pro seismograph. Compressional (P) and shear (S) waves were acquired and the time-term technique, which is a combination of linear least squares and delay time analysis to invert the first arrivals for a velocity section and then to tomography section was adopted. These sections were correlated with a borehole report and a good matching was observed. The result shows that the area consists of three subsurface layers; an overburden with average thickness of about 10.5 m and P- and S-wave velocities (velocities) of about 550 m/s and 345 m/s respectively, the weathered basement with an average thickness of 12.5 m and velocities of 950 m/s and 550 m/s respectively, while the fresh basement was found at a depth of about 24 m with velocities of 1250 m/s and 680 m/s respectively. The Concentration Index, Material Index, Poisson’s Ratio, and Stress Ratio were calculated to be in the range of 4.869 – 6.128, -0.032 – 0.312, 0.172 – 0.258, and 0.267 – 0.346 respectively in the study area. The seismic velocity values, engineering consolidation, and strength parameters showed that the subsurface soil/rock at the eastern parts of the study area is characterized by less competent soil/rock quality while the western parts are characterized by more competent soil/rock quality. Hence, the western and northwestern parts are more preferable for the foundation of structures to be erected
References
Abd El-Rahman, M., (1991). The potential of absorption coefficient and seismic quality factor in delineating less sound foundation materials in Jabal Shib Az Sahara area, Northwest of Sanaa, Yemen Arab Republic. Egypt, M. E. R. C. Earth Sci., Vol. 5. Ain Shams University, pp. 181–187.
Abd El-Rahman, M., (1989). Evaluation of the kinetic elastic moduli of the surface materials and application to engineering geologic maps at Maba-Risabah area (Dhamar Province), Northern Yemen. Egypt. Journal. Geol. 33 (1–2), 229–250.
Adams, L.H., (1951). Elastic properties of materials of the Earth’s Crust. Internal Construction of the Earth (edited by Gutenberg). Dover publications, Inc., New York.
Akintorinwa, O. J., and Adeusi, F. A., (2009). Integration of geophysical investigations for a proposed lecture room complex at the federal university of technology, Akure, SW, Nigeria. Journal of Applied Sciences 2(3).
Birch, F., (1966). Handbook of physical constants. Geol. Soc. Amer. Men. 97, 613. 85
Bullen, K. E., and Bruce, A. B., (1993). An Introduction to the theory of seismology, fourth edition.
Charles, F. N., and Williams P. O., (2005). Seismic refraction analysis of landslides. Geophysics and Geology branch California Department of Transportations, Sacramento.
Gassman, F., (1973). Seismische Prospektion. Birkhaeuser Verlag, Stuttgart, p. 417. 86.
Gardner, G.H.F., Gardner, L.W., Gregory, A.R., (1974). Formation velocity and density – The diagnostic basics for stratigraphic traps. Geophysics 39, 770 -780.
Hydro Skill Ltd., (2006). Hydrological log of boreholes at students’ hostels, Ahmadu Bello University, Zaria.
King, T.V.V., (1966). Mapping organic contamination by detection of clay-organic processes. Proceeding AGWSE/NWWA/API.
McCurry, P. (1970). The Geology of the Zaria sheet 102 S.W. and its Region. Mortimore, M.J. (Ed.). Department of Geography Occasional Paper No. 4, Ahmadu Bello University, Zaria. pg 7.
Salem, H.S. (1990). The theoretical and practical study of petrophysical, electric and elastic parameters of sediments. Germany, Kiel Insitut for geophysik. Ph.D. thesis.
Sheriff, R.E., and Geldart, L.P., (1986). Exploration Seismology. Cambridge Univ. Press, Cambridge, p. 316.
Tatham, R.H., (1982). Vp/Vs and lithology. Geophysics 47 (3), 336–344. https://doi.org/10.1190/1.1441339.
Toksoz, M.N., Cheng, C.H., and Timur, A., (1976). Velocities of seismic waves-porous rocks. Geophysics 41, 621 – 645.
Copyright (c) 2023 FUDMA JOURNAL OF SCIENCES
This work is licensed under a Creative Commons Attribution 4.0 International License.
FUDMA Journal of Sciences
