GEOTECHNICAL INVESTIGATION OF THE PROPOSED IFE DAM SITE AT KAJOLA VILLAGE, ILE-IFE, SOUTHWESTERN NIGERIA

Geological and geophysical investigations were conducted to assess the competence and structural integrity of the foundation site of the proposed Ife-dam at Kajola Village, Ile-Ife, Southwestern Nigeria. Geological investigation along the two (2) proposed dam axes revealed that the overburden material is loose to dense with angular shearing resistance (ɸ) of 27o to 41o. The soils are predominantly elastic silts; cohesive with considerable strength and stability. Geophysical investigation involving the Schlumberger Vertical Electrical Sounding delineated four (4) lithologies namely: topsoil with resistivity of 69 – 558 Ωm and thickness between 1.5 and 4.0 m; weathered sandy layer with resistivity from 123 – 586 Ωm and thickness between 6.5 and 20.4 m; partially weathered/ fractured basement with resistivity from 60 – 220 Ωm and thickness between 6.5 and 14.0 m; and the fresh basement rock with resistivity from 1337 – 10683 Ωm. There are indications of fractures at a depth of 32 m beneath Axis B extending to Axis A at a depth of 35 m. The subsurface materials are suitable to host a dam. Axis B is more appropriate for the dam axis, although the fracture zone should be factored into the design of the dam to prevent water seepage.

Orthogonal tests of the lubricating performance of SnO2 nanoparticles in poly-alfa-olefine oil

The tribological properties of SnO2 nanofluids were investigated using ball-on-plate reciprocating sliding wear tests. It was found that the coefficient of friction was reduced by 34.9% using 3 wt% SnO2 nanoparticles. The wear width and wear depth were reduced by 42% and 50.1%, respectively, using 2 wt% SnO2 nanoparticles. In the orthogonal tests, the frequency had the greatest influence on the friction and wear loss. Additionally, the optimal working conditions were a normal load of 50 N, a motion frequency of 1 Hz, and a surface roughness of 500–600 nm. Additionally, the excellent tribological performance of SnO2 nanofluids could be attributed to the formation of a tribo-film with a low shearing resistance due to the oleic acid and a protective layer due to the embedment of SnO2 nanoparticles.

Study of Clayey Soils with Nonwoven Geotextiles as Liners in Landfill Stabilization

Landfills are highly complex, well-engineered series of cells in or above the ground level. Soil stabilization is the alteration of soils to enhance their physical properties. Landfill stabilization increase the shear strength of soil thus improving the load bearing capacity. Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect or drain. All have a wide range of applications and are currently used to advantage in many civil engineering applications including roads, airfields, railroads, embankments, retaining structures, reservoirs, canals, dams, bank protection and coastal engineering. Typically made from polyester, they are classified into woven, needle punched, heat bonded. nonwoven geotextiles are manufactured by bonding materials together made of synthetics and used in separation applications. Non-woven geotextiles have more gaps of plastic membrane and right choice where pooling water is major concern i.e. drainage systems. In this present study, different geotextiles gives varying advantages. The permeability of the soil can be reduced to desired coefficient and also increased based on the type of geotextile used. The angle of shearing resistance (angle of internal friction) would be lower than that of the unreinforced soils. The performance of the geotextiles depends upon the index properties of the soil.