Geotechnical evaluation of some residual soils from south-western Nigeria as mineral seals in sanitary landfills (original) (raw)
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Journal of Environment and Earth Science, 2016
This study investigates the geotechnical properties of Azara clayey soils from Northcentral Nigeria for its potential use as liner in sanitary landfill. Six (6) samples were taken at about 2.5m interval each along exposed cliff and subjected to laboratory analyses. The required parameters for soils to be considered as mineral seal such as grain size distribution, Atterberg consistency limits, maximum dry density and hydraulic conductivity were determined using the BS 1377 1990 standard. Results obtained show that the grain size analysis of the soils samples are silty clayeysand and clayeysand. The results of Atterberg limit show that the samples can be grouped as low clay soils and medium clay soils. Compaction test analysis shows that sample 3 has the highest optimum moisture content (OMC) value of 10.25%. Sample 2 has the highest maximum dry density (MDD) value of 1.95g/cm 3 while samples 3 have the least MDD value of 1.52g/cm 3 for modified compaction test. The results of hydraulic conductivity (K) reveal that sample 6 has the least value of 1.2 x 10-8 cm/s, and sample 1 has the highest value of 3.0 x 10-7 cm/s which falls within value of various waste regulatory agencies. In addition, three samples have adequate basic geotechnical properties and strength characteristics which suggest the potential suitability of the soils as mineral seal in containment facility for disposal of solid waste materials.
Civil and Environmental Research, 2013
Urbanization and population rise are major factors that contribute to increase quantity of waste generation and its disposal constraint especially in developing countries. This study investigates the geotechnical properties of five soils from southwestern Nigeria for their use as liners in sanitary landfill for disposal of solid waste. The required parameters for soils to be considered as liners were determined in accordance with the British Standard Institute. Results obtained showed that the percentage of fines range from 42% to 82% and index of plasticity values range from 25.0% to 32.6%. Clay activity varies between 0.47 and 0.88. Thus, the soils are classified as non-expansive clay of low to medium plasticity. The maximum dry density values at standard Proctor energy of compaction range from 1.46g/cm 3 to 1.96g/cm 3 while those obtained at modified Proctor energy range from 1.57g/cm 3 to 2.09g/cm 3 .The highest coefficient of permeability value obtained for all soils investigated is 2.99 x 10-9 m/s. All values compare favourably with those suggested by regulatory agencies. Consequently, they are suitable for use as liners in sanitary landfills.
Geotechnical analysis of two Nigerian soils for use as clay liners
Bulletin of Engineering Geology …, 2009
The cretaceous Auchi shale and the Tertiary Imo shale in SW Nigeria were investigated for their suitability for use as a clay seal in waste disposal landfills. Geotechnical analyses indicated they are highly plastic inorganic clays. Although their geotechnical and chemical properties were within the range suggested by various authors for use as mineral seals, care would need to be taken with the Okada shales as they contain smectite and would be difficult to work and liable to cracking.
GEOTECHNICAL INVESTIGATIONS OF A SITE IN AJIBODE, SOUTHWESTERN NIGERIA FOR LANDFILL
Indiscriminate disposal of wastes generated by the increasing human population and industries pollute surface and groundwater, consequently creating health hazards. An evaluation of a site in southwestern Nigeria was undertaken to investigate geotechnical properties of residual soils for use as isolation barriers and to generate baseline information on soil vulnerability, necessary in assessing site suitability for waste disposal. Geological mapping of rocks in the area was undertaken while Geotechnical parameters namely, grain size distribution, consistency limits, permeability and Unconfined Compressive strength were also determined. The soils possessed amount of fines (30.0-73.0 %) and clay content (11.3-38.7 %) that are within the minimum 30 % and 10 % respectively considered adequate for a landfill site. Furthermore, they are well graded exhibiting low to medium plasticity with plasticity index of 9.1 to 20.3 % and low leakage potential of 0.3-0.4 cm/s. Permeability coefficient (k) ranged from 4.7 x 10-8-1.9 x 10-6 cm/s and was within the range of 10-8-10-6 cm/s required for attenuation by natural geological barriers with no likelihood of lateral movement of leachate. Geotechnical evaluation of the site indicated that the study area is geologically stable, geotechnically safe and therefore suitable for waste disposal.
The geotechnical characteristics of some southwestern Nigeria clays were evaluated with a view to determining their suitability for use as barrier soils in waste disposal sites. Clay soils (consisting of twenty disturbed and twenty undisturbed samples) were subjected to grain size, consistency limits and permeability tests. In addition the clay mineralogy and major oxide composition of the soils were determined. The clays are well-graded soils of low plasticity containing adequate percentage clay size fractions and amount of fines showing soils with high -4 specific surface which allow low migration of leachate. The coefficient of permeability ranges from 1.18 x 10 to -7 1.45 x 10 cm/s indicating low to practically impermeable soils. Clay mineralogy revealed the presence of mixed clays -kaolinite-bentonite and kaolinite-illite, hence, their capabilities to attenuate and contain leachate. The studied clays are good barrier soils.
Geotechnical and Geological Engineering, 2017
Sanitary landfills are waste disposal method that functions without creating nuisance to the environment. It confines waste to the available area, reduce waste to the minimum practical volume. The waste in a landfill reacts to release a cocktail of contaminants called leachate, which posses treat to the surrounding environment (soil and groundwater). Therefore, barrier soils are required for the lining of a landfill to prevent seepage of leachate into the surrounding groundwater and subsequent contamination of the groundwater system. Some clay in Minna was assessed using geotechnical techniques to determine its suitability as barrier soils. Five samples of clay were subjected to grain size analysis, atterberg limits, compaction tests and mineralogy test. From the grain size analysis and the atterberg limit, the soil is classified as a clayey material. The liquid limit ranged from 45.5%-61% with a mean value of 51.8% which is an indication of high plasticity and low hydraulic conductivity, the plastic limit ranged from 29.2%-35.8% with a mean value of 32.44% and its plasticity index ranged from 13.7%-25.2% with a mean value of 19.37% which implies that the clay can withstand volumetric shrinkage on drying and exhibit a low to medium swelling potential when wet. The compaction test reveal an optimum moisture content(OMC) ranging from 17.7% to 24% with a mean value of 19.94% and a maximum dry density (MDD) that varied from 1.59g/cm 3 to 1.76g/cm 3 with a mean value of 1.7g/cm 3. This results of these geotechnical analysis suggests that the clay in the area meets the requirement for a barrier soil. The X-ray diffraction analysis reveals the presence of kaolinite dominated clay and mixed clay (kaolinite-illite). These minerals have the capability to attenuate and contain leachates from wastes. Hence, the studied clays are good barrier soils.
Indiscriminate disposal of wastes generated by the increasing human population and industries pollute surface and groundwater, consequently creating health hazards. An evaluation of a site in southwestern Nigeria was undertaken to investigate geotechnical properties of residual soils for use as isolation barriers and to generate baseline information on soil vulnerability, necessary in assessing site suitability for waste disposal. Geological mapping of rocks in the area was undertaken while Geotechnical parameters namely, grain size distribution, consistency limits, permeability and Unconfined Compressive strength were also determined. The soils possessed amount of fines (30.0 -73.0 %) and clay content (11.3 -38.7 %) that are within the minimum 30 % and 10 % respectively considered adequate for a landfill site. Furthermore, they are well graded exhibiting low to medium plasticity with plasticity index of 9.1 to 20.3 % and low leakage potential of 0.3 -0.4 cm/s. Permeability coefficient (k) ranged from 4.7 x 10 -8 -1.9 x 10 -6 cm/s and was within the range of 10 -8 -10 -6 cm/s required for attenuation by natural geological barriers with no likelihood of lateral movement of leachate. Geotechnical evaluation of the site indicated that the study area is geologically stable, geotechnically safe and therefore suitable for waste disposal.
GEOTECHNICAL CHARACTERISTICS OF SOME SOUTHWESTERN NIGERIAN CLAYS AS BARRIER SOILS
The geotechnical characteristics of some southwestern Nigeria clays were evaluated with a view to determining their suitability for use as barrier soils in waste disposal sites. Clay soils (consisting of twenty disturbed and twenty undisturbed samples) were subjected to grain size, consistency limits and permeability tests. In addition the clay mineralogy and major oxide composition of the soils were determined. The clays are well-graded soils of low plasticity containing adequate percentage clay size fractions and amount of fines showing soils with high-4 specific surface which allow low migration of leachate. The coefficient of permeability ranges from 1.18 x 10 to-7 1.45 x 10 cm/s indicating low to practically impermeable soils. Clay mineralogy revealed the presence of mixed clays-kaolinite-bentonite and kaolinite-illite, hence, their capabilities to attenuate and contain leachate. The studied clays are good barrier soils.
Evaluation of a location at Aba-Kuiodi adjacent to kilometre 8 aiong the Ibadan / lle-ife expressway, Southwestern Nigeria was carried out to determine its suitability or otherwise as a landfill site. Two Vertical Electrical Soundings (VES) 30.00m apart were executed to obtain subsurface information on depth to bedrock and possibly the water table. Disturbed and undisturbed soil samples were collected from each of the two trial pits established at vertical interval of 0.50m up to a depth of 3.00m. The disturbed samples were subjected to grain size distribution and consistency limits tests while consolidation and permeability tests were carried out on undisturbed samples. The VES results revealed 3 geo-electric layers with depths to bedrock of between 14.30m and 17.60m at VES 1 and VES 2 respectively. The depths to water table measured from an existing nearby well were 8.10m and 7.00m during the dry and rainy seasons respectively, suggesting that the water table lies within the second geo-electric layer. The soil samples taken from the depth of 3.00m in the two pits are generally well-graded non-plastic sandy clayey silt, a possible indication of no compressibility. The coefficients of permeability obtained for samples from pits 1 and 2 ranges from 1.85 x 10^mm/s to 3.91 x lO^mm/s and 1.91 X 10' 4mm/s to 2.91 xlO^mm/s respectively. The coefficient of permeability obtained for samples taken from the 3.00m depth in the two pits are significantly higher than the minimum value of lO^mm/s recommended for soil that should form the base of landfills. The coefficient of volume compressibility at the sampling pits 1 and 2 range from 1.83 to 7.69 x10'3 m2/KN but generally increases with applied pressure (31.2-498.9 KN/m2) and decrease with depth (0.5'to 3.0m). Statistical treatment of the values of the coefficient of compressibility of soil samples from the depth of 3.00m in the two test pits shows no significant variation, an indication that there is no likelihood of differential settlement if the site is used for disposal of solid wastes. If in-situ compaction and lining are done, the location can be used as a landfill site.
Geotechnical Properties of Clay Soilsin Uyo Town, Eastern Niger Delta, Nigeria.
IOSR Journals , 2019
This study investigates, the geotechnical and mineralogical properties of clay soils in Uyo town, for construction purposes. On the basis of the field and laboratory investigations, the general subsurface profile of Uyo town consists of silty clays from 0-3m, sandy clays (3-15m) and sand from 10-20m.The silty clays are firm with a low to intermediate plasticity and high cohesion values, while the sandy clays, are also of low to intermediate plasticity, with high consolidation and cohesion values, that are expected to yield relatively higher shear strength than the silty clays. X-raydifraction analysis of the clays reveal the presence of kaolinite, quartz and trace amounts of goethite in the silty clays. Analysis of the foundation potentials using CPT results show that the silty clays have low potentials while the underlying sandy clay horizon may be suitable for small and medium civil engineering structures.