GEOPHYSICAL AND GEOTECHNICAL CHARACTERIZATION OF AudRECLAIMED LAND FOR CONSTRUCTION PURPOSES IN LAGOS NIGERIAud(A CASE STUDY)

摘要

Near-surface seismic refraction and electrical resistivity methods were used to characterise the subsurfaceudcondition of a site reclaimed from water bodies in order to determine its competence for construction purposes. Nine seismicudrefraction profiles were acquired and the results were interpreted using SeisImager software. Also, twelve vertical electricaludsoundings were conducted and the acquired data were interpreted using WinResist computer package. Four-five geoelectricudlayers were delineated and the resistivity values obtained ranges between 23.3 and 1705.1m . The result of the resistivityudmethod showed that the third layer is the most competent layer in the study area. The depth of this layer is between 7.5 m andud51 m in the subsurface. In a related development, three layers were delineated by the seismic refraction method and the thirdudlayer which is between 7 m and 18 m, may be the most competent because it had the highest engineering parameters. TheudYoung modulus of the competent layer at this site ranges between 1.558 and 25.106 GPa and bulk modulus ranges fromud0.999 to 16.093GPa , it was also noted that the shear modulus ranges between 0.638 and 10.123 GPa . There is anudagreement in the results of the two methods of investigation. Therefore, it was recommended that some form of arrangementudmust be made to transfer the load from the civil engineering construction to the most competent layer underneath so as toudavoid building failure.