Details

Autor(en) / Beteiligte

• Falowo, Olumuyiwa Olusola

Titel

Geoengineering soil characterization and modeling of highway route along Owo–Ikare (F-215) pavement, Southwestern Nigeria: towards reconstruction/rehabilitation

Ist Teil von

• Arabian journal of geosciences, 2023, Vol.16 (8), Article 499

Ort / Verlag

Cham: Springer International Publishing

Erscheinungsjahr

2023

Link zum Volltext

Quelle

SpringerLink

Beschreibungen/Notizen

• The understanding of geological, groundwater condition, and engineering properties of the soil/rock on which highway is constructed will definitely aid the accurate design and construction of the highway. In this study, soil domain within highway alignment of Owo–Ikare which represents a segment of F-215 was investigated due to incessant failures being experienced along the pavement. The study utilized integrated approach, involving geophysical (electrical resistivity), hydrogeological (static water level and hydraulic head measurements), geochemical analysis (SiO 2 , Al 2 O 3 , and Fe 2 O 3 ), and geotechnical methods (in situ trial pit, dynamic cone penetration, and laboratory tests). The results showed that the topsoil/subsoil on which the soil is constructed is composed of incompetent/fairly competent clay, sandy clay, and laterite. The depth to basement rock ranged between 15.9 and 34.1 m. The basement relief is rugged and dips towards the northeast. The geochemical analysis showed the upper 1 m to be non-lateritic with S-S ratio of 2.06, while the clay mineralogy are within the illite–montmorillonite group. The soil is SC-SM of low plasticity and compressibility with avg. plasticity index of 19.5%. The calculated GI was 6 indicating fair subgrade material. The in situ CBR (avg. 28%) and soaked CBR (avg. 19%) satisfied the 10% minimum specification for subgrade. The DCPT indicated the soil to be generally of medium/dense consistency with penetrative index of 2.4–66.4 mm/blow. It also showed that 536–944 mm depth range is the suitable depth to host the road structure based on the CBR and SNG with relative densities of 0.320–0.487. The SNG, SN, and SNP contributions of the soil are good for subgrade and subbase, but low for base material. Consequently, the expected average thickness of the highway should range from 124 (good zone) to 445 mm (weak zone) (avg. 246 mm), as, against 158 mm measured, this may be the reason for the incessant failure of the highway, in conjunction with a lack of drainage facility at the shoulders of the highway. The regression models of all parameters gave strong positive correlations for most of the parameters measured