Geotechnical Mapping of Benin and environs

The project area is defined by longitudes 005º 30' and 005º 45'E and latitudes 6º 15' and 6º 30'N with a total area of approximately 625km2. The area lies within 1:50,000 Sheet 298 Benin City N.W. The area cuts across four Local Government Areas namely Oredo, Egor, Ikpoba Oka and part of Uhunmwonde. The main town in the area is Benin City. Other settlements include Ikhue Niro, Ute, Obanyator, Etete ,Utoka, Ahor, etc.\r\n\r\nThis was aimed at providing relevant geotechnical information that would aid in mitigating the problem of building collapse. \r\n\r\nThe study area is underlain by the coastal plains sands of the Niger Delta region of the country. \r\n\r\nSoil samples were collected from pits dug to 1m and from boreholes drilled to 6m. Samples collected were analyzed in the laboratory for soil acidity, particle size distribution, Atterberg limits, Triaxial Compression. In-situ Standard Penetration testing was carried out in boreholes drilled at sixteen locations. Samples were collected from the boreholes at 1.5m intervals for Consolidation test. \r\n\r\nPercentage fines ranged from 12.10% to 57.50%. Soils were classified as clayey, silty sand. Liquid limit ranged from 21.50% to 47.50%, Plasticity Index ranged from 3.40 to 24.20 while Shrinkage Limit ranged from 7.70 to 15.30. The soils showed no swelling potential and are highly erodible. The soil pH ranged from 4.36 to 5.42, Specific gravity ranged from 2.61 to 2.76 and dry unit weight ranged between 417.40g to 473.50g. Permeability ranged from 6.82 x 10-7 to 4.80 x 10-4 which is very low. Maximum Dry Density ranged from 1756kg/m3 to 2078kg/m3. Shear strength ranged from 91.3kPa to 170 kPa. Areas suitable for location of waste disposal sites covers about 38% and about 25% is suitable for development of housing estates.Determination of in-situ soil conditions

Date (Publication)

Presentation form: Digital document

Status: Completed

Point of contact

Organisation name	Individual name	Role
		Author
A&EG, NGSA		Publisher
A&EG, NGSA		Custodian
A&EG, NGSA		Point of contact
	Director, A&EG	Owner

Keywords

Soil Strength, Soil Permeability, Soil Type, Slope Stability, Landform, Building Collapse

Other constraints: Internal only

Denominator: 50000

Language: English

Topic category

Description: Nigeria, Edo State, Benin City

Reference system identifier: 4326

Distribution format

Name	Version
.doc

OnLine resource

Protocol	Linkage	Name
		Geotechnical Mapping of Benin and environs

Statement: Inserted in the reports are the following maps (1:50,000): Slope stability map; Ternary Image; Geological map; Accessibility map; Potential Flood Prone Zone map; Flood Risk map; Digital Terrain Model; Structural map; and Permeability map.