Scholars@Duke
Fred K. Boadu

Fred K. Boadu

Associate Professor of Civil and Environmental Engineering
Civil and Environmental Engineering
boadu@duke.edu
Box 90287, Durham, NC 27708-0287
163 Hudson Hall, Box 90287, Durham, NC 27708

Scholarly Works - Journal articles

Potential improvements in montmorillonite-nanoclay-modified Cold-Mix Asphalt

Journal article Case Studies in Construction Materials · December 1, 2022 Over the years, Cold-Mix Asphalts (CMAs) used principally for pothole patching and partial-depth repairs in Ghana have performed abysmally. Given the convenience, environmental friendliness and low cost associated with CMA production, the use of the materi ... Full text Cite

Predicting seismic velocity and other rock properties from clay content only

Journal article Geophysics · January 1, 2021 It has been shown that accurate predictions of compressional and shear-wave velocities can be derived from measurements of clay content, porosity, and bulk density. In this paper, we test the efficacy of using a sequence of established petrophysical formul ... Full text Cite

A support vector regression approach to predict geotechnical properties of soils from electrical spectra based on Jonscher parameterization

Journal article Geophysics · May 1, 2020 Electrical-conductivity spectra of soils contain valuable information about their texture, structure, and composition that can be linked to their geotechnical properties. Concurrent measurements of electrical spectra in the frequency range of 0.01 Hz to 10 ... Full text Cite

Evaluating effective stress conditions in soils using non-invasive electrical measurements – Laboratory studies

Journal article Journal of Applied Geophysics · March 1, 2020 Changes in the effective stress conditions in soils affect their strength with implications on the stability of near-surface earth materials. The ability to, therefore, characterize and monitor the gradual loss of soil strength due to a decrease in effecti ... Full text Cite

Assessing Relations between Electrical and Geotechnical Properties of Sand-Clay Mixtures Using Jonscher Fractal Power Law Model

Journal article Journal of Environmental and Engineering Geophysics · March 1, 2019 The geotechnical properties of unconsolidated geo-materials such as soils are influenced by modifications of their micro-structure, texture, mineralogy, water content and imposed effective stress levels. Fundamental relations between the characteristic ele ... Full text Cite

Deriving SPT N-Values from DCP Test Results: The Case of Foundation Design in a Tropical Environment

Journal article Geotechnical and Geological Engineering · August 1, 2018 A portable standard dynamic cone penetrometer (DCP) was used to overcome the challenge encountered in generating SPT N-values for the design of the foundation of power transmission towers traversing a tropical forest, large parts of which was inaccessible ... Full text Cite

Regression Models to Estimate Critical Porosity of Soils from Basic Soil Properties Based on Percolation Theory

Journal article Geotechnical and Geological Engineering · April 1, 2018 The rigidity of geo-materials (e.g., soils and sediments) reduce significantly, as their porosity increases to a critical value, the critical porosity. Knowledge of critical porosity can be useful in assessing the deformational characteristics of these mat ... Full text Cite

A laboratory study of horizontal confinement effect on the dynamic cone penetration index of a lateritic soil

Journal article Transportation Geotechnics · March 1, 2017 The Dynamic Cone Penetrometer (DCP) has been proposed as a potentially effective tool for compaction quality verification but the correlation equations are established in situ, which is tedious and time consuming. This study is part of a larger study seeki ... Full text Cite

Introduction to the JEEG-NSG geotechnical assessment and geo-environmental engineering geophysics special issue

Journal article Journal of Environmental and Engineering Geophysics · December 1, 2013 The recent surge in the development of new technologies and analysis tools lends weight to that theory, and today we have numerous means to solve many of the complex engineering problems associated with the natural and built environments. Geotechnical prop ... Full text Cite

Artificial neural network and statistical models for predicting the basic geotechnical properties of soils from electrical measurements

Journal article Near Surface Geophysics · January 1, 2013 The ability to predict the geotechnical properties of subsurface soils using non-invasive geophysical measurements can be undeniably useful to the geotechnical engineer. Using laboratory data, we assess the potential of artificial neural networks to invest ... Full text Cite

Exploring the linkages between geotechnical properties and electrical responses of sand-clay mixtures under varying effective stress levels

Journal article Journal of Environmental and Engineering Geophysics · June 1, 2011 The strength and stability conditions of unconsolidated geo-materials, for example soils, are influenced by modifications of their micro-structure, texture, mineralogy and effective stress levels. These modifications in the internal structures of the soils ... Full text Cite

Predicting the engineering and transport properties of soils using fractal equivalent circuit model: Laboratory experiments

Journal article Geophysics · January 1, 2011 Frequency-dependent electrical measurements of soils contain useful information about their texture and structure that can be linked to their engineering and transport properties. We performed frequency-dependent electrical measurements on 29 natural soils ... Full text Cite

Influence of petrophysical and geotechnical engineering properties on the electrical response of unconsolidated earth materials

Journal article Geophysics · January 1, 2010 We have investigated the influence of petrophysical and geotechnical engineering properties of unconsolidated near-surface geomaterials (soils) on their electrical responses or measurements. Complex resistivity measurements were performed at a constant eff ... Full text Cite

Reply to the discussion

Journal article Geophysics · January 1, 2009 Full text Cite

Geotechnical parameters from integrated geophysical methods: Laboratory measurements and regression models

Journal article Environmental and Engineering Geophysical Society 21st Symposium on the Application of Geophysics to Engineering and Environmental Problems 2008 · December 1, 2008 Seismic and electrical measurements are performed in the laboratory on unconsolidated geomaterials with well-characterized geotechnical properties. The measured seismic parameters are compressional wave velocity (V p) and shear wave velocity (V ... Cite

Exploring the linkages between geotechnical properties and geophysical responses of unconsolidated materials - Laboratory measurements

Journal article Environmental and Engineering Geophysical Society 21st Symposium on the Application of Geophysics to Engineering and Environmental Problems 2008 · December 1, 2008 Upon application of stress, the strength and stability of unconsolidated geo-materials are influenced by modifications of their micro-structure, texture and effective stress conditions. These modifications in earth's subsurface often result in geo-hazards ... Cite

Humanitarian geophysics

Journal article Environmental and Engineering Geophysical Society 21st Symposium on the Application of Geophysics to Engineering and Environmental Problems 2008 · December 1, 2008 Seventy percent of the earth's surface is covered by ocean and approximately 97% of the earth's water is saline. Two percent of the earth's water is contained in ice sheets and glaciers. There remains one percent of the water that is available as a resourc ... Cite

Nitrate contamination in groundwater at farmlands in Nsawam, Ghana: The role of fractures from azimuthal resistivity surveys

Journal article Journal of Environmental and Engineering Geophysics · March 1, 2008 The role of fractures in nitrate contamination of fractured groundwater aquifers at farmlands within the Nsawam district (Ghana) is investigated using azimuthal square-array resistivity measurements. The study covers seven farming communities where azimuth ... Full text Cite

Effects of clay content and salinity on the spectral electrical response of soils

Journal article Journal of Environmental and Engineering Geophysics · September 1, 2006 The spectral electrical responses (SER) of sand and clay mixtures subjected to an effective stress of 20 MPa and saturated with varying concentrations of NaCl are measured in a laboratory environment in the frequency range 10 -2 to 10 4 Full text Cite

Determining subsurface fracture characteristics from azimuthal resistivity surveys: A case study at Nsawam, Ghana

Journal article Geophysics · January 1, 2005 We conducted azimuthal resistivity surveys (ARS) using the square-array configuration to characterize the subsurface fractured rock mass at selected farmland sites in Nsawam District, Ghana. This study is the first of its kind in Ghana, and it provides use ... Full text Cite

Use of multifractal seismic waveform parameters to characterize the hydraulic properties of fractured media: Numerical experiments

Journal article Geophysical Journal International · November 1, 2003 The multifractal characteristics of seismic waveforms that have propagated through fractured media were studied using numerical experiments. The study suggests that multifractal waveform parameters (i.e. information dimension, correlation dimension, curvat ... Full text Cite

Relating Electrical Response and Petrophysical Properites of Sands Subjected to Stress Changes

Journal article Journal of Environmental and Engineering geophysics · 2002 Cite

Chapter 11 Permeability estimation with an RBF network and Levenberg-Marquardt learning

Journal article Handbook of Geophysical Exploration Seismic Exploration · December 1, 2001 Full text Cite

Predicting oil saturation from velocities using petrophysical models and artificial neural networks

Journal article Journal of Petroleum Science and Engineering · September 1, 2001 The degree of oil saturation has been estimated from velocity measurements of unconsolidated sediments at a laboratory scale using a petrophysical model and artificial neural network (ANN) as an inversion tool. Laboratory measurements of velocities, V ... Full text Cite

Predicting the transport properties of fractured rocks from seismic information: Numerical experiments

Journal article Journal of Applied Geophysics · May 1, 2000 The hydraulic properties including porosity and permeability of fractured rock masses are estimated from seismic velocities derived from controlled numerical experiments. Models of fractured media are developed to represent fractures embedded in an otherwi ... Full text Cite

Wave propagation in fluid-saturated media: Waveform and spectral analysis

Journal article Geophysical Journal International · April 1, 2000 A new numerical approach to the solution of waves propagating in a fluid-saturated medium, using Biot's theory as a foundation, has important implications for oil reservoir management and earthquake prediction. A numerical scheme is developed using an expo ... Full text Cite

Neural inversion for oil saturation from seismic velocities

Journal article Seg Technical Program Expanded Abstracts · January 1, 2000 The degree of oil saturation has been estimated from velocity measurements of unconsolidated sediments in a laboratory environment using a petrophysical model and artificial neural network (ANN). Velocities, Vp, Vs, and their ratio V< ... Full text Cite

Estimating Hydraulic Conductivity and Porosity of Soils from Spectral Electrical Response Measurements

Journal article J. of Engineering. & Environmental. Geophysics · 2000 Cite

Hydraulic conductivity of soils from grain-size distribution: New models

Journal article Journal of Geotechnical and Geoenvironmental Engineering · 2000 This paper presents new developments of regression-based models to predict the saturated hydraulic conductivity of compacted soils from grain-size distribution. The models incorporate parameter values that adequately represent the distribution of grain siz ... Full text Link to item Cite

Inversion of fracture density from field seismic velocities using artificial neural networks

Journal article Geophysics · January 1, 1998 The inversion of fracture density from field measured P- and S-wave seismic velocities is performed using a neural network trained with an output from the modified displacement discontinuity fracture model. The basic idea is to use input-output pairs gener ... Full text Cite

Rock properties and seismic attenuation: Neural network analysis

Journal article Pure and Applied Geophysics · January 1, 1997 Using laboratory data, the influence of rock parameters on seismic attenuation has been analyzed using artificial neural networks and regression models. The predictive capabilities of the neural networks and multiple linear regresssion were compared. The n ... Full text Cite

Fractured rock mass characterization parameters and seismic properties: Analytical studies

Journal article Journal of Applied Geophysics · January 1, 1997 Analytical studies have been carried out based on a modified displacement discontinuity fracture model to characterize the relations between seismic properties and fractured rock mass parameters. Models of a fractured medium are developed to represent vert ... Full text Cite

Relating the hydraulic properties of a fractured rock mass to seismic attributes: Theory and numerical experiments

Journal article International Journal of Rock Mechanics and Mining Sciences · January 1, 1997 Numerical experiments are conducted to establish how the properties of a seismic signal are related to the hydraulic properties of a fractured rock mass. A hybridized reflectivity method is developed and used to compute a 1D synthetic seismogram for a geol ... Full text Cite

Effects of fractures on seismic-wave velocity and attenuation

Journal article Geophysical Journal International · January 1, 1996 The effects of fractures on the seismic velocity and attenuation of a rock are investigated using theoretical results and experimental data. Fractures in a rock mass influence the traveltimes and amplitudes of seismic waves that have propagated through the ... Full text Cite

Statistical distribution of natural fractures and the possible physical generating mechanism

Journal article Pure and Applied Geophysics Pageoph · June 1, 1994 We have fitted field measurements of fracture spacings (from the vicinity of Lake Strom Thurmond, Georgia, U.S.A.) to the Weibull, Schuhmann and fractal distributions. The fracture spacings follow a fractal and Weibull distribution which implies that they ... Full text Cite

The fractal character of fracture spacing and RQD

Journal article International Journal of Rock Mechanics and Mining Sciences and · January 1, 1994 Fracturing and fragmentation processes occur on all scales and, hence, may be described in terms of fractals. We examined the fractal dimensions of discontinuity spacing measurements in a fractured rock mass and observed a relation between the fractal dime ... Full text Cite

Policy on private water sales in rural Ghana

Journal article Journal of Water Resources Planning and Management · 1994 This paper examines strategies for forming public-private sector partnerships in order to improve the distribution of water in rural areas in Ghana. The options explored include: (1) An outright sale of the existing government-controlled water corporation; ... Cite

Law and natural-resource development. Case of water in Lesotho

Journal article Journal of Water Resources Planning and Management · 1991 This paper examines the role of the Lesotho Water Resources Act of 1978 in national development. The paper concludes that the act could be very effective in promoting equitable and efficient use of water resources in the country if it is properly implement ... Cite