scholarly journals Engineering Site Investigation and Shallow Foundation Design in Ore Area of Ondo State, Nigeria

2020 ◽  
Vol 67 (1) ◽  
pp. 21-33
Author(s):  
O. Falowo Olumuyiwa
Keyword(s):  
Bearing Capacity ◽  
Soil Analysis ◽  
Site Investigation ◽  
Shallow Foundation ◽  
Cone Penetration ◽  
Foundation Design ◽  
Overburden Thickness ◽  
Allowable Bearing Capacity ◽  
Weathered Layer ◽  
Electrical Sounding

AbstractThe study integrates geophysical and geotechnical methods for subsoil evaluation and shallow foundation design. The study involved six vertical electrical sounding and geotechnical investigation involving cone penetration test and laboratory soil analysis. Three major geologic units were delineated; the topsoil, weathered layer and partly weathered/fractured/fresh bedrock. The overburden thickness is in between 15.2–32.9 m. Based on resistivity (16–890 ohm-m) and thickness (12.7–32 m) the weathered layer is competent to distribute structural load to underlying soil/rock. The groundwater level varies from 4.5 to 12.3 m. Therefore an average allowable bearing capacity of 200 kPa is recommended and would be appropriate for design of shallow foundation in the area, at a depth not less than 1.0 m with an expected settlement ranging from 9.03–48.20 mm. The ultimate bearing and allowable bearing capacity for depth levels of 1–3 m vary from 1403–2666 kPa and 468–889 kPa for strip footing while square footing varies in between 1956–3489 kPa and 652–1163 kPa respectively.

scholarly journals Engineering Subsoil Characterization for Shallow Foundation Design in Ode Irele Area of Ondo State, Southwestern Nigeria

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Olumuyiwa O. Falowo ◽  
Michael B. Amodu
Keyword(s):  
Bearing Capacity ◽  
Shallow Foundation ◽  
Soil Conditions ◽  
Cone Penetration ◽  
Foundation Design ◽  
Southwestern Nigeria ◽  
Foundation Soil ◽  
Geotechnical Investigations ◽  
Allowable Bearing Capacity ◽  
Coastal Sand

Integrated geophysical and geotechnical investigations for foundation design have proved to be good veritable tools in effective foundation design and construction. Geophysical and geotechnical methods involving electrical resistivity and cone penetration test have been carried out to investigate the foundation soil conditions of Ode Irele, southwestern Nigeria. Six vertical electrical sounding (VES) were carried out along two traverses; which is complemented by two cone penetration tests with seven trial tests at different subsurface depths. The geotechnical results showed that the soils are sand and silt dominated. All the tested parameters fall within the Nigeria federal ministry of works and housing specification with liquid limit (< 50%), plastic limit (< 30%), plasticity index (< 20%). The geoelectric sections identified maximum of six geoelectric/geologic subsurface layers comprising the topsoil (red sand), weathered layer (made up of coastal sand/white sand), clayey sand (which is the major aquitard in the area), intermediate sand aquifer unit. However the coastal sand layer has moderately high resistivity at shallow depth to sustain foundation load with thickness greater than 2 m. The groundwater level measured from existing borehole records 17.5 m which may not or seriously affect the bases of the foundation footing. Consequently an average allowable bearing capacity of 150 KN/m2 (ultimate bearing capacity of 450 KN/m2) would be appropriate for design of shallow foundation in the area, at a depth not less than 1.6 m in Ode Irele and 0.8 m at Ajagba. The foundation width of 0.6 m would produce minimum bearing settlement less than 25 mm. The appropriate (recommended) ultimate bearing and allowable bearing capacity for strip and square footings at depth levels of 0.6 – 1.2 m vary from 1486 – 1842 KN/m2 and 495 - 614 KN/m2; and 2056 – 2489 KN/m2 and 685 - 830 KN/m2 respectively.

scholarly journals Engineering Site Investigation for Foundation Design and Construction in Shale and Sandstone Derived Soils of Okitipupa Area, Southwestern Nigeria

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
FALOWO OLUSOLA OLUMUYIWA
Keyword(s):  
Site Investigation ◽  
Shallow Foundation ◽  
Cone Penetration ◽  
Foundation Design ◽  
Deep Foundation ◽  
Southwestern Nigeria ◽  
Building Foundation ◽  
Allowable Bearing Capacity ◽  
Engineering Standards ◽  
Electrical Soundings

Geotechnical and geo-electrical investigations of Okitipupa has been carried out with the major objectives of establishing the subsoil/geology, evaluate the geotechnical properties and recommend appropriate foundation alternatives for building foundation construction. Seven borings were carried out with hand auger at two cone penetration test locations, and representative samples were collected and analyzed in the laboratory in accordance with relevant geotechnical engineering standards. In addition, six vertical electrical soundings (VES) were also conducted using Schlumberger configuration. The result of VES delineates three major geologic sequence comprising the topsoil/caprock, sand surficial aquifer, and sand intermediate aquifer. The topsoil has resistivity range of 242 – 1503 ohm-m and thickness of 3.4 - 20.9 m composed of clay sand and sand. This layer is capable of supporting shallow foundation such as simple spread, raft of reinforced concrete, with recommended allowable bearing pressure of 100 KN/m2 at depths of 1.0 m and 3.2 m in the northern and southern part of the study area respectively. The estimated settlement are less than 50 mm using foundation width of 0.6 m, but could be reduced by almost 50% if the width is greater than or equal to 2 m. The groundwater level is very deep (>10 m) and may not likely threatens the integrity of the foundation structures. The estimated allowable bearing capacity for strip footing (203 – 980 KN/m2), square footing (608 – 2940 KN/m2) within 1.4 m depth is appropriate. The capacity of driven (deep foundation) circular piles of diameters 400mm, 500mm, and 600mm, the recommended pile capacity varies at depth of 5 m (69 – 124 KN), 10 m (225 – 378 KN), and 15 m (470 – 766 KN), while that of bored circular pile ranges from (36 – 75 KN), 10 m (93 – 180 KN), and 15 m (170 – 317 KN).

scholarly journals Subsoil Engineering Characterization and Foundation Design in Derived Geological Coastal Sands of Ilaje Area of Ondo State, Nigeria

2020 ◽  
pp. 458-468
Keyword(s):  
Bearing Capacity ◽  
Shallow Foundation ◽  
High Resistivity ◽  
Building Structures ◽  
Cone Penetration ◽  
Foundation Design ◽  
Geotechnical Parameters ◽  
Design Alternatives ◽  
Allowable Bearing Capacity ◽  
Ondo State

Engineering subsoil evaluation and foundation design have been undertaken at Ilaje area of Ondo State, Nigeria. The aim of this study was to examine the geo-electrical and geotechnical parameters of the subsoil to sustain building structures and also provide appropriate foundation design alternatives. A total of six VES stations were occupied and complemented with geotechnical analysis of seven soil samples collected at two cone penetration test locations. The result showed that all the determined geotechnical parameters of the subsoil fall within the specification recommended for foundation material by federal ministry of works and housing of Nigeria. The VES showed a predominant (66.67%) HKQ curve type. The upper 5 m is characterized by moderate thickness and high resistivity (average of 450ohm-m) values to sustain structural load. An average allowable bearing capacity of 150 KN/m2 was recommended for design of bases/footings for shallow foundation at a depth not less than 1.0 m. The obtained settlement values are less than 50 mm and within tolerable limit, for foundation width ranging from 0.5 to 3.0 m. However there was drastic reduction in settlement values (below 25mm) when the foundation width was increased to 2 and 3m. The allowable capacity of the driven pile ranges from 64 – 115 KN, 206 – 347 KN, and 418 – 677 KN at 5m, 10 m and 15 m respectively. The allowable bearing capacity for bored piles ranges from 34 – 69 KN, 85 – 165 KN, and 146 – 268 at depth levels of 5 m, 10 m, and 15 m respectively.

Hydrogeophysical investigation for the aquifers in part of Ilorin, Central Nigeria: Implication on groundwater prospect

2021 ◽  
Vol 47 (2) ◽  
pp. 520-534
Author(s):  
Ayodele Kehinde Olawuyi
Keyword(s):  
Groundwater Resources ◽  
Groundwater Potential ◽  
Mean Value ◽  
Groundwater Prospect ◽  
Basement Complex ◽  
Type Curves ◽  
Lateritic Clay ◽  
Overburden Thickness ◽  
Weathered Layer ◽  
Electrical Sounding

Hydrogeophysical study involving the use of Vertical Electrical Sounding (VES) was carried out in part of the basement complex rocks of Ilorin, central Nigeria, with the aim of determining its geoelectric parameters and groundwater potential. A total of thirty (30) VES were carried out using Schlumberger electrode configuration, with half electrode separation (AB/2) varying from 1m to 100m. Information on the subsurface lithologies, overburden thickness and aquiferous layers were obtained from the different VES locations in the study area. From the quantitative interpretations of the data collected, using the method of curve matching with the Orellana-Mooney master curves and 1-D forward modeling with WinResist 1.0 version software, three to five lithologic units were identified in the study. These include: the topsoil, sandy/lateritic clay/laterite, the weathered basement, the fractured basement and the fresh bedrock which are predominantly of the ‘KH’ curve type (30%), followed by ‘H’ type (26.7%), other type curves include ‘QH’ (16.7%), ‘HKH’, ‘HA’ and ‘A’ (6.7% each) and KQ and KQH (3.3% each). The weathered layer and the fractured basement constitute the main aquifer units. The aquifers are of generally low resistivity values (mostly below 100 Ω-m). The depths to dry bedrock at the chosen VES locations vary from 2.7 to 62.7 m with a mean value of 13.02 m in the study area. The geoelectrical interpretations of data obtained in these areas have permitted the delineation of the study area into low and moderate groundwater potential zones. This study is expected to assist in future planning for groundwater resources. Keywords: Hydrogeophysical, Basement Complex, Groundwater, Electrical Soundings, Weathered, Fractured

Nomographs for predicting allowable bearing capacity and elastic settlement of shallow foundation on granular soil

2019 ◽  
Vol 12 (15) ◽  
Author(s):  
Maher Omar ◽  
Abdallah Shanableh ◽  
Khaled Hamad ◽  
Ali Tahmaz ◽  
Mohamed G. Arab ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Shallow Foundation ◽  
Granular Soil ◽  
Allowable Bearing Capacity ◽  
Elastic Settlement

scholarly journals Geophysical and Geotechnical Studies of a Proposed Structure at Akure, Southwestern Nigeria

2018 ◽  
pp. 1-12
Author(s):  
Ilugbo Stephen Olubusola ◽  
Adebo A. Babatunde ◽  
Ajayi Oluwasayo Adegbola ◽  
Adewumi Olufemi Olaoluwa ◽  
Edunjobi Hazeez Owolabi
Keyword(s):  
Clay Content ◽  
Geotechnical Investigation ◽  
Cone Penetration ◽  
Geophysical Investigation ◽  
Engineering Structures ◽  
Southwestern Nigeria ◽  
Weathered Layer ◽  
Electrical Sounding ◽  
Geoelectric Resistivity ◽  
Geotechnical Studies

Geophysical and geotechnical studies were carried out at a proposed location for the construction of a multi-storey structure in Akure, Southwestern, Nigeria. The aim was to ascertain the suitability of this location for both Founding and Engineering structures. The geophysical investigation involved the Vertical Electrical Sounding (VES) technique using the Schlumberger configuration, Dipole-Dipole Horizontal Profiling and a geotechnical investigation. A total of twenty-one (21) VES and five (5) Cone Penetration Test (CPT) locations were occupied within the study site. Dipole-Dipole Horizontal Profiling was occupied along traverses 1 and 2 within the investigated area. The electrode separation varies from 1 to 75 m. The investigation delineated three major layers which are topsoil, which is excavated before any foundation is laid. The second layer delineated was lateritic and the last was weathered layer. From the result obtained, depth to lateritic layer ranges from 1.1 to 9.0 m while resistivity defining the lateritic layer ranges from 150 Ωm to 792 Ωm. Some of the sounding curves generated over the VES stations and Dipole-Dipole Horizontal Profiling fairly correlated with those of the CPT profile. The high cone penetration resistance recorded at CPT point 4 and 5 is manifested as high geoelectric resistivity values recorded at VES 13. This shows that the soil has fairly low clay content. It also seen from the study that the geophysical studies has a greater depth penetration, and it also provide better layer characterization compared to geotechnical studies. The choice of foundation material, clay content and topography elevation should be taken into cognizance, since the load bearing capacity of the lateritic layer was appreciably high.

scholarly journals Correlation between Electrical Resistivity and Cone Penetrometer Test Data for Geotechnical Site Investigation

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
I. A. Akinlabi
Keyword(s):  
Electrical Resistivity ◽  
Bearing Capacity ◽  
Test Data ◽  
Empirical Relation ◽  
Site Investigation ◽  
Cone Penetrometer ◽  
Soil Resistivity ◽  
Empirical Relationships ◽  
Cone Resistance ◽  
Allowable Bearing Capacity

The use of the electrical resistivity method provides cost-effective subsurface information faster and allows reliable interpolation to be made between the tested points. It is therefore desirable to generate consistent data from resistivity measurements by using empirical relationships while only few zones of interest will require testing. This study, therefore, developed empirical relationships between electrical resistivity sounding and cone penetrometer test data for engineering site investigation using a case study from the Basement Complex Terrain of Southwestern Nigeria. Regression analysis was used to assess the correlation between the soil resistivity and cone resistance and the validity of the empirical relation was evaluated by comparing values estimated from the soil resistivity vs. cone resistance cross plot with field values obtained from cone penetration tests. The values of allowable bearing pressure computed by using both values in Meyerhof’s equation were also compared with the allowable bearing capacity deduced with laboratory values of soil strength parameters (cohesion, angle of internal friction, soil unit weight) in Terzaghi’s general formula. The results show close agreement between the measured and estimated values with the differences typically less than 10%. The standard errors of the estimates for the cone resistance and allowable bearing capacity are 2.70 and 4.16 respectively, implying reliability of the estimates. The proposed empirical relationships, therefore, appear to provide reasonable estimation of soil cone resistance and allowable bearing capacity from soil resistivity. Few complimentary cone penetrometer and laboratory tests will thus be required while the cost and duration of site investigation for engineering structures are expected to reduce.

scholarly journals Daya Dukung Tanah Fondasi Dangkal Pada Bukit Hambalang Bagian Selatan, Kecamatan Citeureup, Kabupaten Bogor

2017 ◽  
Vol 8 (3) ◽  
pp. 143
Author(s):  
Rifki Asrul Sani
Keyword(s):  
Bearing Capacity ◽  
Standard Penetration Test ◽  
Geological Mapping ◽  
Shallow Foundation ◽  
Soil Parameters ◽  
Penetration Test ◽  
Square Footing ◽  
Local Soil ◽  
Allowable Bearing Capacity ◽  
Shear Condition

ABSTRAKSeiring dengan terjadinya longsoran di beberapa titik wilayah di bukit Hambalang, maka diperlukan kajian data kondisi geologi teknik berupa sifat fisik dan mekanik tanah serta batuan bawah permukaan, terutama mengenai daya dukung tanah dalam menahan beban bangunan di atasnya agar tidak terjadi penurunan. Metode yang digunakan dalam penelitian ini dibagi menjadi tiga, yaitu metode penelitian studio dengan memanfaatkan data-data sekunder yang telah ada, metode penelitian di lapangan melalui pemetaan geologi untuk mendapatkan data litologi yang tersingkap di permukaan, zonasi longsoran yang terjadi, dan identifikasi kekuatan tanah hasil pemboran geoteknik dengan Standard Penetration Test (SPT), serta metode penelitian di laboratorium untuk mendapatkan parameter sifat fisik dan mekanik tanah sebagai penunjang data daya dukung tanah serta geologi teknik daerah penelitian. Hasil perhitungan fondasi dangkal untuk general soil shear condition dan local soil shear condition dapat disimpulkan bahwa daya dukung tanah yang diizinkan (qa) untuk setiap kedalaman yang paling tinggi pada fondasi bujur sangkar (square footing) dan nilai tertinggi yang terdapat pada kedalaman 2 m, yaitu 57,32 ton/m2 dan 36,11 ton/m2. Fondasi yang paling rendah untuk semua kedalaman pada fondasi menerus (continuous footing) untuk kedalaman 2 m memiliki nilai 34,49 ton/m2 dan 21,25 ton/m2. Berdasarkan data SPT, nilai daya dukung yang diizinkan (qa) pada masing-masing titik bor berkisar pada rentang 2,85 ton/m2 sampai 16,85 ton/m2. Kata kunci: longsoran, daya dukung, Standard Penetration Test (SPT). ABSTRACTAlong with the landslide in some areas on the Hambalang Hill, it needs data of engineering geological study such as mechanical and physical properties of soil also subsurface rocks. Especially regarding the soil bearing capacity in order to restrain the building from settlement. There are three methods which used in this research, those are studio research by using secondary data, fieldwork research that is geological mapping conducted to obtain data on lithological rocks at surface, landslide zone and soil strength identification from geotechnical drilling with Standard Penetration Test (SPT) and laboratory research to obtain the soil parameters of physical and mechanical properties, which used to support soil bearing capacity data and engineering geology in research area. The calculation results of the shallow foundation for general soil shear condition and the local soil shear condition it could be concluded that the allowable bearing capacity for all depth which is highest at the square footing and the highest value found to a depth of 2 m, that is 57.32 ton/m2 and 36.11 ton/m2. The lowest foundation for all the depth of the continuous footing to a depth of 2 m had value 34.49 ton/m2 and 21.25 ton/m2. Based on data from SPT, the allowable bearing capacity on each of borehole ranging from 2.85 ton/m2 to 16.85 ton/m2. Keywords: landslide, bearing capacity, Standard Penetration Test (SPT).

scholarly journals A Framework to Predict the Load-Settlement Behavior of Shallow Foundations in a Range of Soils from Silty Clays to Sands using CPT Records

2021 ◽  
Author(s):  
Hossein MolaAbasi ◽  
Aghileh Khajeh ◽  
REZA JAMSHIDI CHENARI ◽  
Meghdad Payan
Keyword(s):  
Bearing Capacity ◽  
Volterra Series ◽  
Current Model ◽  
Shallow Foundations ◽  
Hyperbolic Function ◽  
Cone Penetration ◽  
Settlement Behavior ◽  
Tip Resistance ◽  
Allowable Bearing Capacity ◽  
Load Tests

Abstract Using a set of cone penetration test (CPT) records,the current paper develops a general framework based on regression analyses to model the load-settlement (q-s) behavior of shallow foundations resting on a variety of soils ranging from silty clays to sands.A three-parameter hyperbolic function is employed to rigorously examine the obtainedq-s curves, and to determine the model parameters.Also, the results of someCPT soundings, including the corrected cone tip resistance (qt) and the skin friction (Rf),are adopted to predict the results of plate load tests(PLT). The findingscorroborate the high accuracy of the proposed model, thereasonable performance of the hyperbolic function and the use of the Volterra series to predict the q-s curves.Moreover, the obtained curves from the newly developed model arecompared to those from other methods in the literature which cross-confirms the efficacyof the current model. Asensitivity analysis isalso conductedand the exclusive effects of all the contributing parameters are assessed among which Rfis shown to be the most influential. Ultimately, simple solutionsare adoptedto determine variouskey geotechnical parameters, like the ultimate bearing capacity (qult), the allowable bearing capacity (qa) andthe modulus of subgrade reaction (ks).

scholarly journals Geophysical and Geotechnical Site Characterization at Lagos Central Area of Lagos State, Nigeria

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Rafiu Adegbola ◽  
Kayode Oyedele ◽  
Elizabeth Abidoye
Keyword(s):  
Central Area ◽  
Maximum Load ◽  
Shallow Foundation ◽  
Silty Sand ◽  
Cone Penetration ◽  
Engineering Structures ◽  
Shallow Subsurface ◽  
Subsurface Geology ◽  
Electrical Sounding ◽  
A Site

Introduction: Geophysical characterization refers to the collection of information associated with subsurface features. Geotechnical involves engineering structural performance studies which are used to obtain information on the physical properties of soil and rock around a site to design earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions. Aim: The study was aimed at characterizing the subsurface formations for the purpose of determining its capacity to withstand engineering structures. Materials and Methods: Geophysical techniques involving eight (8) vertical electrical sounding (VES) and Wenner array were carried out with two (2) traverses. Geotechnical investigation involving cone penetration test (CPT) was also carried out. Results: The results obtained were presented as 1D resistivity profiles and Pseudo-sections of 2-D. Three (3) geo-electric layers were delineated within the study area and these comprise of topsoil, peat or clay and silty sand. The CPT results were used in the calculation of bearing capacity using Bustamante and Gianeselli equation for pile foundations and Meyehorf equation to determine the maximum load the materials can withstand respectively. Conclusion: The shallow subsurface geology was adjudged to be mechanically unstable with low penetration resistance values up to the depth of 11m. The methods conformed and confirmed that shallow foundation was considered unsuitable for the intended engineering structure. Keywords: Meyehorf, Bustamante and Gianeselli, Subsurface, Geology, Unstable, Foundation.

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