Evaluation of Sub-Soil Geotechnical Properties for Shallow Foundation and Pavement Design in LASPOTECH, Ikorodu Campus, Lagos State, Nigeria

Abstract

Sequel to continuous failure of structures all over the country, adequate knowledge of the geotechnical characteristics of underlying soils at construction sites has become very desirable for foundation design and construction of civil engineering structures. This study aims at investigating and establishing the sub-soil types and profile to determine the engineering characteristics of the underlying soils within the Ikorodu Campus of the Lagos State Polytechnic, Ikorodu, Lagos, Nigeria and recommend appropriate foundation and road pavement design. Forty Dynamic Cone penetrometer tests were performed alongside eight borings which were accomplished using percussion rig with augers. Representative soil samples were obtained and analyzed in the laboratory in accordance with relevant geotechnical engineering standards. Result of the study showed that the study area was found to consist of about 0.35m thick of organic top soil followed by 9m thick of reddish lateritic sandy clay. The study also revealed that the superficial lateritic soil has a bearing capacity ranging from 130 kN/m 2 at 1.0m depth to 243 kN/m 2 at 2.5m depth. Shallow foundation with bearing capacity of 150kN/m 2 at footing depth not lower than 1.2m is recommended for general use within the campus. Maximum expected settlement is estimated at 27.84mm. Similarly, a CBR value of 7% is recommended as subgrade CBR value for road pavement design within the campus.