ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES ADDIS ABABA INSTITUTE OF TECHNOLOGY DEPARTMENT OF CIVIL ENGINEERING INVESTIGATION ON SOME OF THE ENGINEERING CHARACTERISTICS OF SOILS IN ADAMA TOWN, ETHIOPIA (original) (raw)
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Journal of Civil Engineering Research, 2020
Investigation of the ground conditions is used for the economical design of the sub-structural elements. It is also necessary to obtained sufficient information on type, characteristics and distributions of a soil and rock underlying at a site of proposed structures for feasibility and economic studies for the proposed project. Thus the purpose of this article was to investigate engineering properties of the soils Wolkite University. To achieve the objective samples from different parts of the compound were collected and laboratory tests were done on the collected samples. The grain size analysis test result showed that the dominant proportion of soil particle in the research area is clay, which have clay content ranging from 5.4-40 5%, silt faction 17.6-60.7%, sand fraction 14.5-54.6% and gravel content from 0.0-24.8%. The result of Atterberg Limit test on the soil in the research area showed a liquid limit ranging from 29-73%, plastic limit ranging from 21-35% and plastic index from 13-34%. The specific sravity ranges from 2.40 to 2.70. Free swell test conducted on the samples collected shows range from 18-50%. From the compaction test results the maximum dry density (MDD) of wolkite University soil ranges from 1.20 to 1.62 g/cm 3 and the optimum moisture content ranges 17.5 to 36.5 percent. According to the Unified Soil Classification System, the soil is categorized as silt and silty sand. Finally one-dimensional consolidation test was done and it shows that the area under investigation is over consolidated in its natural state, have compression index ranging from 0.33-0.40, recompression index ranging from 0.017-0.066, and coefficient of permeability ranging from 10-7 to 10-9 cm/sec.
Life Science Journal, 2013
Assessment of variation in soil parameter is required to proceed for structural design of foundations. This study aims to develop the zoning of the project area on the bases of extensive experimental work in laboratory and field tests performed at the number of locations of the project area. The zones are developed based on similar characteristics of different soil parameters. The data points have been marked on the base map of the study area along with the boundaries of the zones. The experimental data of the study area has shown potential for development of three zones. The subsurface soils in zone A consist of low plastic fill material up to 2.0 m depth overlaying low plastic clay from 2.0 m to 4.0 m and low plastic clay/clayey silt beyond 4.0 m depth. Zone B consists of low plastic clay and clayey silt up to the depth of 4. meter overlaying clayey silt to silt with sand material from 4.0 m to 6 m depths and gravel with sand beyond 6.0 meter depth. In zone C, low plastic clay/clayey silt is found up to 2.0 m depth overlaying silty sand up to 4.0 m depth and gravel with sand beyond 4.0 m depth. Number of blows (N Value) of standard penetration test (SPT) for Zone A is less than 8, for Zone B, it ranges from 8-15 and for Zone C, N value is greater than 15. The resultant data can be helpful during planning stage of the project and during feasibility study of mega projects. The research work is extendable to develop the geotechnical zoning map of any specific area and it can be part of building code.
Soil sampling and testing is one of the most important steps to attain success in construction projects. Soil testing provides information on type of soil, Bearing capacity of soil etc., An unprecedented amount of construction projects has been delay or even being cancelled because of soil unsuitability. Soil samples have been collected from the proposed site to check suitability for the construction of commercial complex. Tests such as Field dry density, Natural moisture content , particle size analysis, soil fraction retained on 4.75mm ISS, Soil fraction passing 4.75mm ISS, Atterbergs limits, Specific gravity, Shear test, Direct shear test, Consolidation test and Differential free swell test are done for testing the suitability and stability of soil for the construction of commercial complex.
The stability and performance of a structure founded on soil depend on the subsoil conditions, ground surface features, type of construction, and sometimes the meteorological changes. Subsoil conditions can be explored by drilling and sampling, seismic surveying, excavation of test pits, and by the study of existing data. Elaborate site investigation oftentimes cannot be conducted due to a limited assigned budget. For very favorable sites, such investigation may not be warranted. However, if the area is suspected of having deep fill, a high water table, or swelling soil problems, extensive soil investigation will be necessary even for minor structures. The soil engineers should not accept jobs in problem areas without thorough investigation. Bear in mind that in court of law, limited budgets or limited time frames are not excuses for inadequate investigation. Differing site conditions are a favorite tool of the contractors. They are used as the basis for extra claims on their contracts. Since a consulting soil engineer cannot afford to treat each site as a potential hazard area, the amount of investigation required will generally be dictated by the judgment and experience of the engineers. If the project is completed on time and under budget, the consultant may still be criticized for being too conservative. On the other hand, if problems are encountered in the project, no number of excuses can relieve consultants of their responsibility. 2 Soil Engineering: Testing, Design, and Remediation 1.1 GENERAL INFORMATION The content of this chapter has very little to do with soil engineering. However, as a consultant, site investigation is probably one of the most important parts of the total inquiry or the report. Average owners know very little about engineering, but they do know a great deal about the property they own. Misrepresentation of the observations can often cause a great deal of trouble. For instance, describing the property as located in a low-lying area may devalue the property. Pointing out the cracks in the building owned by someone else in the neighborhood may induce the buyer to decrease the offer and in extreme cases may result in litigation. Valuable information about the presence of fills and knowledge of any difficulties encountered during the building of other nearby structures may be obtained from talking to older residents of the area. Much of the site investigation depends on the experience and good judgment of the field engineer or the technician. An experienced field engineer has the sense of a bloodhound; he is able to smell or sense a problem when he visits the site. A red flag will be raised to call for thorough investigation. In a potential swelling soil area, special attention should be paid to the condition and foundation system of the existing structures. When the site is located out of town, consulting engineering firms sometimes assign site investigation to a technician or a field man, who has little geotechnical experience. He may ignore some important features which should be pointed out in the geotechnical report. An experienced technician with many years of training in a geotechnical company can be worth more than an engineer freshly out of college with a Ph.D. degree. Generally, it is a small building with inadequate funding, poor planning, and a low-bidding contractor that presents the most trouble. The owner of such a project generally considers soil investigation as a requirement fulfillment rather than a protection against foundation failure. Geotechnical engineers should ask for more details
Assessment of engineering properties of soils: A case study
2018
Engineering properties of soils is useful in understanding the properties and behaviour of soils for the management especially erosion control, farming activities, building, etc. The present research was aimed to assess the engineering properties and behavior of the soils in Otukpo local Government Area of Benue State. The engineering properties such as Atterberg limits (e.g., shrinkage limit, liquid limit and plastic limit), bulk density, dry density and optimum moisture content, particle size distribution within were determined from four districts in the Local Government Area. The samples collected from three different points in each district were mixed together and analysed in the SCC Nigeria limited control laboratory. Four samples were analysed, one from each district of Akpa, Uga, Ogboju, and Otukpo respectively. It was observed that Otobi and Obotu soils are uniformly graded, while the Owetor soils are well-graded while Uga soils are gap-graded. The obtained results indicate ...
Engineering properties of the Soils around Aba, South East Nigeria
Engineering properties of the soils around Aba and its environs were investigated. Fifty four (54) bulk samples were taken from test pits dug to a minimum depth of 1.5 metres for Atterberg Limits Test, Grain Size Distribution analysis, Compaction, and California Bearing Ratio determination. Twelve (12) shell and auger boreholes were drilled to 10m using the Pilcon Wayfarer 1500 percussion rig and undisturbed samples were collected in Shelby tubes at selected intervals of 1.5 metre for Triaxial Compression Test, Consolidation test and Grain Size Distribution analysis. Twelve (12) Dutch Cone Penetrometer Sounding Tests were carried out at 10 metres depth or to refusal. The resistance of the soil was measured by means of a dial gauge attachment to the penetrometer machine. The soils classify as very fine sands, silty to clayey fine sands, or clayey silts with slight plasticity (ML), and gravelly clays, sandy and silty clays (CL) according to the Unified Soils Classification scheme (USC). Their bulk density ranged from 1.95Mg/m3 to 2.19 Mg/m3 and Natural Moisture Content varied from 12% to 21%. Cohesion values ranged from 28kN/m2 to 60kN/m2. The Maximum Dry Density (MDD) ranged between 1.09Mg/m3 to 2.17Mg/m3 while the Optimum Moisture Content (OMC) ranges from 9.5% to 19.8%. California Bearing Ratio (CBR) soaked ranged from 5.1% to 11.2% while unsoaked CBR ranged from 7.6% to 18.9%. For design of strip/square footing 1.5metres wide founded at 1.5metres depth, the average allowable bearing capacity of the soils is 25kN/m2 from cone, while the sleeve gives 50kN/m2, allowing maximum differential settlement of 25mm (1 inch), using a factor of safety of 3. For the same footing, under same conditions, the average allowable bearing capacity from SPT was 125 kN/m2 while 279kN/m2 was computed from the Undrained Triaxial Compression Test. Therefore, it is recommended that the Dutch Cone Penetration Test average bearing capacity of 25kN/m2 be used for design. Generally, the soils around Aba are compressible, friable, very loose, to loose, and are suitable as embankment material for road pavements. They are however, unsuited for use in construction of water reservoirs like earth dams and leeves due to their moderate permeability characteristics. They are excavatable in stripping operations.