The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
Mohammad Sharifipour - One of the best experts on this subject based on the ideXlab platform.
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Geotechnical properties of hydrocarbon-contaminated soils: a comprehensive review
Bulletin of Engineering Geology and the Environment, 2019Co-Authors: Hamid Rajabi, Mohammad SharifipourAbstract:The Geotechnical characteristics of hydrocarbon-contaminated soils have been concentrated heretofore due to the alarming frequency of hydrocarbon contaminations and their significant consequences. Over the past three decades, numerous research studies have been conducted in order to investigate hydrocarbon-induced changes in Geotechnical properties of soils. The present article is aimed at extensively reviewing almost all relevant academic literature on this subject, and, due to various kinds of soils and hydrocarbon compounds, it tries to provide a brief summary of each research study along with its key findings. By this review, it was revealed that Geotechnical characteristics of soils, such as particle size distribution, Atterberg limits, permeability, optimum moisture content, maximum dry density, compression index, coefficient of consolidation, over-consolidation ratio, cohesion, angle of internal friction, unconfined compression strength, shear strength, and so on, can be remarkably influenced by hydrocarbon contaminations. However, the amount of these hydrocarbon-induced changes were highly dependent on various factors, including soil and hydrocarbon properties, environmental and operation conditions, weathering process, etc., so that, for each specific Geotechnical Property, various alterations were reported in scientific literature.
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An Experimental Characterization of Shear Wave Velocity (V_s) in Clean and Hydrocarbon-Contaminated Sand
Geotechnical and Geological Engineering, 2017Co-Authors: Hamid Rajabi, Mohammad SharifipourAbstract:The characteristics of hydrocarbon-contaminated soils have been among major concerns of Geotechnical engineers due to its significant frequency of event and also its influential consequences on our surroundings from various environmental and engineering viewpoints. Heretofore, the effects of diverse kinds of hydrocarbon contaminants on majority of Geotechnical properties of fine- and coarse-grained soils such as grain size, hydraulic conductivity, plasticity, compressibility, internal friction, cohesion, and shear strength have been investigated. However, there has not been a concentrated research study examining shear wave velocity ( $${\text{V}}_{\text{s}}$$ V s ) of hydrocarbon-contaminated soils as an important Geotechnical Property of soil due to this fact that, in small/very small strain levels, the maximum shear modulus of soils ( $${\text{G}}_{ \hbox{max} }$$ G max ) can be determined using shear wave velocity ( $${\text{G}}_{ \hbox{max} } =\uprho{\text{V}}_{\text{s}}^{2}$$ G max = ρ V s 2 ). This paper aims to investigate effects of hydrocarbon contamination on shear wave velocity of sandy soils by comparing shear wave velocities in identically prepared clean and contaminated samples. To this aim, an Iranian light crude oil, a standard type of silica sand (Ottawa sand), and a bender element apparatus were used to minutely measure shear wave velocity of clean and crude oil contaminated sand samples. Moreover, dry and quasi-moist tamping methods were employed in order to provide comparable clean and contaminated specimens (containing 4, 6, 8, 10, and 12 wt% of crude oil), respectively. Firstly, a comprehensive bender element (BE) and resonant column tests were conducted on the identically prepared clean sand samples at various amounts of frequency (2–20 kHz) and under various confining pressure (50–500 kPa) to find the best methods of accurately determining shear wave travel time in BE tests. Thereafter, BE tests were conducted to examine shear wave velocity in contaminated specimens. Based on the results, it was found that there was a critical value for crude oil content with the maximum shear wave velocity so that shear wave velocity of 4 wt% contaminated sand (V_s-4 wt%) was about 1.2 times higher than clean one (V_s-clean), and contrastingly adding further crude oil up to 6 wt% made a significant reduction in value of shear wave velocity to some extent that V_s-6 wt% was slightly lower than V_s-clean (V_s-6 wt% = 0.95–0.97V_s-clean). Moreover, adding more contaminant (8–12 wt%) into sand had negligible influences on shear wave velocity. In this paper, the effects of crude oil contamination on sand microstructure were also evaluated using scanning electron microscopy.
Hamid Rajabi - One of the best experts on this subject based on the ideXlab platform.
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Geotechnical properties of hydrocarbon-contaminated soils: a comprehensive review
Bulletin of Engineering Geology and the Environment, 2019Co-Authors: Hamid Rajabi, Mohammad SharifipourAbstract:The Geotechnical characteristics of hydrocarbon-contaminated soils have been concentrated heretofore due to the alarming frequency of hydrocarbon contaminations and their significant consequences. Over the past three decades, numerous research studies have been conducted in order to investigate hydrocarbon-induced changes in Geotechnical properties of soils. The present article is aimed at extensively reviewing almost all relevant academic literature on this subject, and, due to various kinds of soils and hydrocarbon compounds, it tries to provide a brief summary of each research study along with its key findings. By this review, it was revealed that Geotechnical characteristics of soils, such as particle size distribution, Atterberg limits, permeability, optimum moisture content, maximum dry density, compression index, coefficient of consolidation, over-consolidation ratio, cohesion, angle of internal friction, unconfined compression strength, shear strength, and so on, can be remarkably influenced by hydrocarbon contaminations. However, the amount of these hydrocarbon-induced changes were highly dependent on various factors, including soil and hydrocarbon properties, environmental and operation conditions, weathering process, etc., so that, for each specific Geotechnical Property, various alterations were reported in scientific literature.
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An Experimental Characterization of Shear Wave Velocity (V_s) in Clean and Hydrocarbon-Contaminated Sand
Geotechnical and Geological Engineering, 2017Co-Authors: Hamid Rajabi, Mohammad SharifipourAbstract:The characteristics of hydrocarbon-contaminated soils have been among major concerns of Geotechnical engineers due to its significant frequency of event and also its influential consequences on our surroundings from various environmental and engineering viewpoints. Heretofore, the effects of diverse kinds of hydrocarbon contaminants on majority of Geotechnical properties of fine- and coarse-grained soils such as grain size, hydraulic conductivity, plasticity, compressibility, internal friction, cohesion, and shear strength have been investigated. However, there has not been a concentrated research study examining shear wave velocity ( $${\text{V}}_{\text{s}}$$ V s ) of hydrocarbon-contaminated soils as an important Geotechnical Property of soil due to this fact that, in small/very small strain levels, the maximum shear modulus of soils ( $${\text{G}}_{ \hbox{max} }$$ G max ) can be determined using shear wave velocity ( $${\text{G}}_{ \hbox{max} } =\uprho{\text{V}}_{\text{s}}^{2}$$ G max = ρ V s 2 ). This paper aims to investigate effects of hydrocarbon contamination on shear wave velocity of sandy soils by comparing shear wave velocities in identically prepared clean and contaminated samples. To this aim, an Iranian light crude oil, a standard type of silica sand (Ottawa sand), and a bender element apparatus were used to minutely measure shear wave velocity of clean and crude oil contaminated sand samples. Moreover, dry and quasi-moist tamping methods were employed in order to provide comparable clean and contaminated specimens (containing 4, 6, 8, 10, and 12 wt% of crude oil), respectively. Firstly, a comprehensive bender element (BE) and resonant column tests were conducted on the identically prepared clean sand samples at various amounts of frequency (2–20 kHz) and under various confining pressure (50–500 kPa) to find the best methods of accurately determining shear wave travel time in BE tests. Thereafter, BE tests were conducted to examine shear wave velocity in contaminated specimens. Based on the results, it was found that there was a critical value for crude oil content with the maximum shear wave velocity so that shear wave velocity of 4 wt% contaminated sand (V_s-4 wt%) was about 1.2 times higher than clean one (V_s-clean), and contrastingly adding further crude oil up to 6 wt% made a significant reduction in value of shear wave velocity to some extent that V_s-6 wt% was slightly lower than V_s-clean (V_s-6 wt% = 0.95–0.97V_s-clean). Moreover, adding more contaminant (8–12 wt%) into sand had negligible influences on shear wave velocity. In this paper, the effects of crude oil contamination on sand microstructure were also evaluated using scanning electron microscopy.
Fred H Kulhawy - One of the best experts on this subject based on the ideXlab platform.
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Characterization and Estimation of Geotechnical Variability in Ankara Clay: A Case History
Geotechnical and Geological Engineering, 2010Co-Authors: Sami O. Akbas, Fred H KulhawyAbstract:An important component in reliability-based design is the Geotechnical Property variability. Generic estimates are used often, but calibration to a local geologic setting is preferable. In this case history, a methodology is shown that employs local Geotechnical data to estimate the total variability, using Ankara Clay for illustration. A literature review is used to estimate the inherent variability, which is modeled as a random field with coefficient of variation (COV) and scale of fluctuation. The resulting inherent variability COVs are much smaller than the generic ranges. Local correlations between various laboratory and field tests and soil strength and compressibility parameters then are developed to quantify the transformation uncertainties. The various sources of uncertainty are combined through a second-moment method to estimate the total Geotechnical variability as a function of the test type and correlation used. The results show: (1) the COVs for direct laboratory measurements are significantly smaller than those obtained through correlations, and (2) depending on the Geotechnical data available, the local COVs can be very different from the generic guidelines. These could lead to unconservative designs. These issues are illustrated by a simple design example.
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evaluation of Geotechnical Property variability
Canadian Geotechnical Journal, 1999Co-Authors: Kokkwang Phoon, Fred H KulhawyAbstract:To evaluate Geotechnical variability on a general basis that will facilitate the use of reliability-based design procedures, it is necessary to assess inherent soil variability, measurement error, ...
Richard H Bennett - One of the best experts on this subject based on the ideXlab platform.
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Geotechnical Property variability of continental margin sediments high resolution vertical and lateral data from the northern california slope
Marine Georesources & Geotechnology, 1997Co-Authors: William B Sawyer, Barbara Ransom, Richard H BennettAbstract:High‐resolution vertical and lateral gradients and variations in sediment mass physical properties were derived from measurements in box cores, on the scale of millimeters, tens of centimeters, and kilometers from typical, relatively broad areas of the northern California continental slope in the Cape Mendocino area at water depths from 380 to 940 m. Such data are important as a control on comparisons of different sediment suites, as well as providing limits for realistic flux calculations of dissolved inorganic and biochemical species and pollutants. The sediments studied have relatively constant organic carbon contents (OC ? 1.75 wt%) and bulk mineralogy. They range from silty sands (∼45% sand, 40% silt) to clayey silts (∼63% silt, ∼35% clay) and are extensively bioturbated. Physical Property variations between subcores (∼25 to 35 cm in length), taken from the same box core, increase with increasing clay content. For coarse‐grained sediments, mean down‐core differences in physical Property values betwee...
Louis R Bartek - One of the best experts on this subject based on the ideXlab platform.
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use of stochastic modeling of stratigraphic relationships in high resolution seismic reflection data for prediction of the distribution of acoustic and Geotechnical Property variability in near surface sediments on the east china sea continental marg
1999Co-Authors: Louis R BartekAbstract:Abstract : During cruises in May and June of 1999, 7991 km of single channel high resolution seismic data and 5278 km of chirp sub-bottom and side-scan sonar data were collected from the continental margin of the East China Sea (ECS) and Yellow Sea. When these data are pooled with data collected in this region during cruises in 1993 and 1996 the total data available for analyses is 15,408 km of seismic profiles and 13,295 km of chirp sub-bottom and side-scan sonar data along with 51 gravity cores. Copies of these data were provided to the Naval Oceanographic Office at Bay St. Louis, Mississippi. These data were processed to minimize noise and subjected to seismic stratigraphic analyses. Correlation of the data with published drill core descriptions indicate that the seismic profiles image stratigraphy that extends back to at least 200,000 years before present. The results of these analyses revealed that the stratigraphy of the margin was strongly impacted by glacially driven sea level fluctuations that produced regional unconformities that can be used to subdivide the stratigraphy into Lowstand (LST). Transgressive (TST) and (Highstand) systems tracts.