Investigation of the Integrity of Subsoil as Foundation Support for a new Hostel Building, FUT, Akure, Southwestern Nigeria

Main Article Content

J. A. Afelumo
O. A. Ademeso

Abstract

This research investigated the integrity of subsoil as foundation for a new building at the Federal University of Technology, Akure, Nigeria. All tests were carried out in accordance with the ASTM, AASHTO and Federal Ministry of Works and Housing standards. Eleven pits were dug while three samples were collected from top, middle and base layers of each pit totaling thirty-three. The results of natural moisture content (NMC) for the top layer averaged 14.7%, percentages of gravel, sand and fines averaged 26.9, 42.1 and 31.0 respectively, liquid limit (LL) 32.45%, plastic limit (PL) 23.8%, plasticity index (PI) 8.4%, linear shrinkage (LS) 8.4%, specific gravity 2.64, maximum dry density (MDD) 1582kg/m3 while optimum moisture content (OMC) averaged 22.7% and shear strength 24.5Kpa. The middle layer has average NMC of 22.37%, percentages of gravel, sand and fines 29.1, 36.4 and 34.5 respectively, LL 37.25%, PL is 24.9%, PI is 10.64%, LS 8.1%, specific gravity 2.66, MDD is 1638.9kg/m3 while the OMC is 20.73% and shear strength is 29.5kpa. Base layer has average NMC of 20.5%, percentages of gravel, sand and fines 24.6, 36.9 and 38.5 respectively, LL 37.6%, PL 25.1%, PI 12.38%, LS 7.3%, specific gravity 2.63, MDD 1768.7kg/m3 while the OMC is 18.7% and shear strength is 32.4kpa. % fines has a very strong positive correlation with LL, PL, PI, MDD, shear strength and UCS while it has a very strong negative with LS and OMC. It was observed that the top soil is non-critical considering the LL specification, while middle and base soils are intermediate. The inadequacy of the top and middle soils was noticed as a result of the non-compact state considering the bearing capacity and shear strength, while the base soil is characterized by fair MDD and high shear strength. Conclusively, the base layer is suitable as support for foundation.


 

Article Details

Section
Articles

References

Ademeso, O.A. (2009): Deformation Traits in the Charnockitic Rocks of Akure Area, Southwestern Nigeria. Asian Journal of Earth Sciences, 2: pp. 113-120.

American Association of State Highways and Transport Officials, T99 (2015): Standard Method of Test for Moisture-Density Relation of Soils Using 2.5Kg (5.5lb) Rammer and a 305mm (12in) Drop. Vol. 1.1.

American Society for Testing and Materials D4318 (2005): Standard test methods for liquid limilts, plastic limits and plasticity index of Soils. ASTM International, West Conshohocken, PA. www.astm.org

American Society for Testing and Materials D698 (2007): Standard test methods for laboratory Compaction Characteristics of Soils Using Standard Efforts (12400 ft-lbf/ft3 (600KNm/m3). ASTM International, West Conshohocken, PA. www.astm.org

American Society for Testing and Materials D2166 (2006): Standard test methods for Unconfined Compressive Strength of cohesive Soils. ASTM International, West Conshohocken, PA. www.astm.org

Bayode, S., Omosuyi, G.O. and Abdullahi, H.I. (2012): Post –foundation Engineering Geophysical investigation in Part of the Federal University of Technology, Akure, Southwestern Nigeria. J. Emerging Trends Eng. Appl. Sci. (JETEAS). 3(1):203-210.

Bell, F.G. (2007): Engineering Geology 2nd Edition, Butterworth- Heinemann Publishers, Oxford 581p.

Jegede, G. (1994): Soil Erosion Effect on Highway Pavement Failures at Iloda Locality, S-W Nigeria. Proc. Unesco Mab Conffed. Univ. Tech. Akure. Pp153-158

Federal Ministry of Works and Housing (1972): “General Specifications for Roads and Construction`”. Vol. 2, pp.137-275

Olayanju, G.M. (2011): Engineering Geophysical Investigation of a Flood Zone: A Case study of Alaba Layout, Akure, Southwestern Nigeria. J. Geol. Mining Res. 3(8):193-200

Woods, K.B. (1937): Compaction of Embankments. Proc. Highw. Res. Bd, Wash., Vol.18, No 2, pp.142-181

Wright, P.H. (1976): Highway Engineering, Sixth Edition, John Willey and Sons: New York, NY.