Yes

The present work is in the area of site and computational investigations dealing with migration of a dense non-aqueous phase liquid (DNAPL) within a discrete fractures network embedded in a porous rock media at field scale using numerical simulation. The migration of DNAPL in the subsurface is dependent upon surface parameters, subsurface aquifer parameters and other subsurface conditions. Generally, these aquifer parameters govern the temporal and spatial variability of a DNAPL. To understand the source zone architecture and dissolved plume movement in the subsurface, characterization of these relevant subsurface parameters is required with respect to space and time. The present study focuses on a systematic investigation and characterization of fluid and transport parameters at highly contaminated fractured-porous media site located at Smithville, Ontario, Canada. Data used to characterize the Smithville site include site geology, ground surface elevation, historical hydraulic head, hydraulic parameters from packer tests such as hydraulic conductivity, porosity, analyses performed on borehole core samples, pumping rates from recovery wells, and contaminants transport parameters such as DNAPL concentration data. Geostatistical and statistical analysis have been used to generate information on groundwater flow direction, vertical hydraulic gradients, contaminant plume migration and source zone architecture. TCE concentrations and pumping rates have been used to estimate TCE mass removal from the site. Important parameters for use in the multiphase model have been developed, including capillary pressure curves and relative permeability curves for rock matrix and fractures, and pore throat radius of the rock matrix. DNAPL behaves differently in fractured-porous media than it does in porous media. To understand DNAPL behaviour in fractured-porous media, site specific conceptual model development to describe geological, hydrogeological, fracture network, and DNAPL occurrence is required. Prediction of the impact of source mass depletion at highly contaminated fractured-porous media site for achieving regulatory goals, as a contaminant concentration at a down gradient compliance boundary was evaluated using multiphase compositional model CompFlow. The results demonstrate that a large amount of non-aqueous phase DNAPL is present in the Vuggy Dolostone and the Tight Dolostone (23-28m, Low Vinemount) and a small amount is present in Permeable Dolostone (Eramosa). The peak concentration at the compliance boundary is much greater than the maximum acceptable concentration (MAC) for TCE of 0.005 mg/L for drinking water.

The present work is in the area of site and computational investigations dealing with migration of a dense non-aqueous phase liquid (DNAPL) within a discrete fractures network embedded in a porous rock media at field scale using numerical simulation. The migration of DNAPL in the subsurface is dependent upon surface parameters, subsurface aquifer parameters and other subsurface conditions. Generally, these aquifer parameters govern the temporal and spatial variability of a DNAPL. To understand the source zone architecture and dissolved plume movement in the subsurface, characterization of these relevant subsurface parameters is required with respect to space and time. The present study focuses on a systematic investigation and characterization of fluid and transport parameters at highly contaminated fractured-porous media site located at Smithville, Ontario, Canada. Data used to characterize the Smithville site include site geology, ground surface elevation, historical hydraulic head, hydraulic parameters from packer tests such as hydraulic conductivity, porosity, analyses performed on borehole core samples, pumping rates from recovery wells, and contaminants transport parameters such as DNAPL concentration data. Geostatistical and statistical analysis have been used to generate information on groundwater flow direction, vertical hydraulic gradients, contaminant plume migration and source zone architecture. TCE concentrations and pumping rates have been used to estimate TCE mass removal from the site. Important parameters for use in the multiphase model have been developed, including capillary pressure curves and relative permeability curves for rock matrix and fractures, and pore throat radius of the rock matrix. DNAPL behaves differently in fractured-porous media than it does in porous media. To understand DNAPL behaviour in fractured-porous media, site specific conceptual model development to describe geological, hydrogeological, fracture network, and DNAPL occurrence is required. Prediction of the impact of source mass depletion at highly contaminated fractured-porous media site for achieving regulatory goals, as a contaminant concentration at a down gradient compliance boundary was evaluated using multiphase compositional model CompFlow. The results demonstrate that a large amount of non-aqueous phase DNAPL is present in the Vuggy Dolostone and the Tight Dolostone (23-28m, Low Vinemount) and a small amount is present in Permeable Dolostone (Eramosa). The peak concentration at the compliance boundary is much greater than the maximum acceptable concentration (MAC) for TCE of 0.005 mg/L for drinking water.

The research presented in this thesis focuses on the quantification of the effect of limited site investigations on the design and performance of pile foundations. Limited site investigation is one of the main causes of structural foundation failures. Over the last 30 years, most site investigations conducted for infrastructure projects have been dictated by minimum cost and time of completion, rather than meeting the need to appropriately characterise soil properties (Institution of Civil Engineers 1991; Jaksa et al. 2003). As a result, limited site investigations remain common, resulting in a higher risk of structural foundation failure, unforeseen additional construction, and/or repair costs. Also, limited site investigations can result in over-designing foundations, leading to increased and unnecessary cost (ASFE 1996). Based on the reliability examination method for site investigations introduced by Jaksa et al. (2003) and performed by Goldsworthy (2006), this research investigated the effect of limited site investigations on the design of pile foundations. This was achieved by generating three-dimensional random fields to obtain a virtual site consisting of soil properties at certain levels of variability, and by simulating various numbers of cone penetration tests (CPTs) and pile foundations on the generated site. Once the site and the CPTs were simulated, the cone tip resistance (qc) was profiled along the vertical and horizontal axes. The simulated qc profiles yielded by the CPTs were then used to compute axial pile load capacity termed the pile foundation design based on site investigations (SI). In parallel, the axial pile load capacity of the simulated pile foundation utilising the “true” cone tip resistance along the simulated pile was also determined. This is termed “the true” design, or the benchmark pile foundation design, and referred to as pile foundation design based on complete knowledge (CK). At the end of this process, the research compared the pile foundation designs based on SI and those based on CK. The reliability of the foundation design based on SI was analysed with a probabilistic approach, using the Monte Carlo technique. The results indicated that limited site investigations have a significant impact on the design of pile foundations. The results showed that minimum sampling efforts result in a high risk of over- or under-designing piles. More intensive sampling efforts, in contrast, led to a low risk of under- or over-design. The results also indicated that the levels of spatial variability of the soil are notable factors that affect the effectiveness of site investigations. These results will assist geotechnical engineers in planning a site investigation in a more rational manner with knowledge of the associated risks. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375097 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Civil, Environmental and Mining Engineering, 2009

The research presented in this thesis focuses on the quantification of the effect of limited site investigations on the design and performance of pile foundations. Limited site investigation is one of the main causes of structural foundation failures. Over the last 30 years, most site investigations conducted for infrastructure projects have been dictated by minimum cost and time of completion, rather than meeting the need to appropriately characterise soil properties (Institution of Civil Engineers 1991; Jaksa et al. 2003). As a result, limited site investigations remain common, resulting in a higher risk of structural foundation failure, unforeseen additional construction, and/or repair costs. Also, limited site investigations can result in over-designing foundations, leading to increased and unnecessary cost (ASFE 1996). Based on the reliability examination method for site investigations introduced by Jaksa et al. (2003) and performed by Goldsworthy (2006), this research investigated the effect of limited site investigations on the design of pile foundations. This was achieved by generating three-dimensional random fields to obtain a virtual site consisting of soil properties at certain levels of variability, and by simulating various numbers of cone penetration tests (CPTs) and pile foundations on the generated site. Once the site and the CPTs were simulated, the cone tip resistance (qc) was profiled along the vertical and horizontal axes. The simulated qc profiles yielded by the CPTs were then used to compute axial pile load capacity termed the pile foundation design based on site investigations (SI). In parallel, the axial pile load capacity of the simulated pile foundation utilising the “true” cone tip resistance along the simulated pile was also determined. This is termed “the true” design, or the benchmark pile foundation design, and referred to as pile foundation design based on complete knowledge (CK). At the end of this process, the research compared the pile foundation designs based on SI and those based on CK. The reliability of the foundation design based on SI was analysed with a probabilistic approach, using the Monte Carlo technique. The results indicated that limited site investigations have a significant impact on the design of pile foundations. The results showed that minimum sampling efforts result in a high risk of over- or under-designing piles. More intensive sampling efforts, in contrast, led to a low risk of under- or over-design. The results also indicated that the levels of spatial variability of the soil are notable factors that affect the effectiveness of site investigations. These results will assist geotechnical engineers in planning a site investigation in a more rational manner with knowledge of the associated risks. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375097 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Civil, Environmental and Mining Engineering, 2009

Information presented in site investigation reports has a strong influence in design, project costs and safety. For this reason, both the quality and the reliability of site investigation reports are important. However in our country, geotechnical engineering is relegated to second place and site investigation studies, especially parcel-basis ground investigation works / do not receive the attention they deserve. In this study, site investigation reports, that are required for the license of design projects, are examined and the missing/incorrect site investigations, laboratory tests, geotechnical evaluations and geotechnical suggestions that occur in the reports are catalogued. Also, frequency of each mistake is statistically examined / for geotechnical engineers, recommendations and solutions are presented to help them avoid frequent problems.

The purpose of this study is to improve site investigation in geotechnical engineering via the evaluation and development of statistical approaches for characterizing the spatial variability of soil properties and the development of site investigation simulation software for educational use. This study consists of four components: statistical characteristics, data measurement, simulation, and educational training. Statistical measures of spatial variability of soil properties were examined for three different geographical areas where soil formation processes differ to assess the influence on the spatial variability of soils. Statistical measures of spatial variability were also calculated for a case history where blasting was used as a method of soil improvement to evaluate the effects of man-made changes to soil structure. The concept of spatial aliasing was employed to estimate the maximum allowable sampling interval for field data as a function of the spatial correlation properties. Once a maximum statistically allowable sampling interval is determined for a specific soil property, the minimum statistically required number of soundings / borings is calculated to perform an economical site investigation at a specific site. A simple and efficient simulation technique was proposed to generate correlated, multi-dimensional simulations of soil properties. Based on limited data, the proposed simulation technique generated accurate and correlated simulations of soil properties that are consistent with the observed or proposed correlation structures of soil properties. Lastly, a geotechnical site investigation simulation program with a wide variety of in situ and laboratory tests was developed to allow students to plan and perform a comprehensive site investigation program. The simulation generates an input file based partly on the statistical characteristics of the spatial variability of soil properties analyzed in this study and partly on traditional values. Spatial variability in soil properties is modeled via correlated random fields, interpolation, and a decomposition method to yield realistic geotechnical data. Via the simulation, students are able to obtain experience and judgment in an essential component of geotechnical engineering practice. The four components of this research (statistical characteristics, data measurement, simulation, and educational training) focus on the improvement of site investigation performance in geotechnical engineering, thereby improving reliability analysis in geotechnical practice.

Portable Free Fall Penetrometers (PFFPs) are lightweight tools used for rapid and economic characterization of surficial subaqueous sediments. PFFPs vary in weight, shape and size with options for using add-on units. The different configurations enable deployments in various environments and water depths, including the nearshore zone where conventional methods are challenged by energetic hydrodynamics and limited navigable depth. Moreover, PFFPs offer an opportunity to reduce the high site investigation costs associated with conventional offshore geotechnical site investigation methods. These costs are often a major obstacle for small projects serving remote communities or testing novel renewable energy harvesting machines. However, PFFPs still face issues regarding data analysis and interpretation, particularly in energetic sandy nearshore areas. This includes a lack of data and accepted analysis methods for such environments. Therefore, the goal of this research was to advance data interpretation and sediments characterization methods using PFFPs with emphasis on deployments in energetic nearshore environments. PFFP tests were conducted in the nearshore areas of: Yakutat Bay, AK; Cannon Beach, AK; and the U.S. Army Corps of Engineers' Field Research Facility's beach, Duck, NC. From the measurements, the research goal was addressed by: (1) introducing a methodology to create a regional sediment classification scheme utilizing the PFFP deceleration and pore pressure measurements, sediment traces on the probe upon retrieval, and previous literature; (2) investigating the effect of wave forcing on the sediments' behavior through correlating variations in sediment strength to wave climate, sandbar migration, and depth of closure, as well as identifying areas of significant sediment mobilization processes; and (3) estimating the relative density and friction angle of sand in energetic nearshore areas from PFFP measurements. For the latter, the field data was supported by vacuum triaxial tests and PFFP deployments under controlled laboratory conditions on sand samples prepared at different relative densities. The research outcomes address gaps in knowledge with regard to the limited studies available that investigate the sand geotechnical properties in energetic nearshore areas. More specifically, the research contributes to the understanding of surficial sediment geotechnical properties in energetic nearshore areas and the enhancement of sediment characterization and interpretation methods. / PHD / The increasing demand for energy, fluctuations of oil prices, and the expected reduction in the world’s oil production in addition to concerns associated to the global climate change drive the search for renewable energy sources. Out of the different sources of renewable energy, the reliable availability of waves is an advantage over other sources like solar and wind. However, different challenges are still facing the advancement of generating energy from waves. One important challenge is the reliability of the anchoring or foundation system, and the associated site characterization and data collection. The stability of the systems depends on the sediment strength (ability accommodate loads), sediments susceptibility to scour (removal of the sediments around the foundations), and local morphodynamics (changes in the seabed shape). In fact, the stability of the foundations in the seabed represents a major concern for many nearshore and offshore structures. Accordingly, the site characterization stage of any project is essential to mitigate the risks of failures, as well as to achieve cost-effective designs. Portable Free fall penetrometers (PFFPs) are rapid and economical tools used to characterize uppermost seabed sediments. The variability of such devices in weight, shape and size enables the use in different environments and water depths. However, data of PFFPs in sandy sediments is still limited which contradicts the fact that sand represents the most common soil type on the beaches worldwide. Accordingly, the aim of this research is to investigate the sediment behavior in energetic wave areas, and to advance the methods of interpreting the PFFP data in sandy nearshore zones. A PFFP was used to characterize the sediments in three main areas: Yakutat Bay, AK, Cannon Beach, AK and the U.S. Army Corps of Engineers’ Field Research Facility’s beach, Duck, NC. The results were utilized to introduce a sediment classification scheme and complete an existing sediment distribution map for Yakutat Bay, AK; study the effect of storms on the seabed sediment strength; and to determine sand strength parameters using PFFP measurements. The results of this research will contribute to improve the sediment characterization methods and to understand topmost sediment layers’ properties.

[pt] A dissertação apresenta o levantamento hidrogeológico de um sítio experimental na Formação Barreiras. Neste sítio, localizado no município de São Sebastião do Passé (BA), foi realizado um levantamento de campo que compreendeu a execução de sondagens, construção dos poços de monitoramento, ensaios de condutividade hidráulica, coleta de amostras deformadas e pseudoindeformadas e levantamento geofísico por GPR (Ground Penetrating Radar). O programa experimental realizado em laboratório buscou caracterizar geotécnica e mineralogicamente os materiais coletados. Verificou-se que o perfil estratigráfico do sítio possui uma série de materiais dispostos em camadas pouco espessas. Embora os materiais apresentem constituição mineralógica semelhante, a sua distribuição granulométrica e os seus limites de consistência são díspares. Verificou-se a inexistência de uma relação direta entre a condutividade hidráulica e a porosidade, porém foram constatadas excelentes relações entre a condutividade hidráulica e o teor de finos, a fração argila, a fração grossa, o limite de liquidez e o índice de plasticidade. A modelagem geológica realizada através dos dados obtidos no decorrer da execução das sondagens a trado, dos poços de monitoramento e da sondagem geofísica revelou que a distribuição espacial dos distintos materiais não é uniforme, posto que a localização das camadas e a suas respectivas espessuras variam ao longo do perfil. / [en] The dissertation presents a hydrogeological survey of an experimental site from Barreiras Formation. On this site, located in the municipality of São Sebastião do Passé (BA), a site investigation was carried out consisting on auger drilling, construction of monitoring wells, hydraulic conductivity tests, sample collection a and a geophysical survey by GPR (Ground Penetrating Radar). The experimental program held at the Geotechnical Laboratory sought to characterize the mineralogical and geotechnical properties of the materials collected. It was found that the profile of the site has a series of materials arranged in thin layers. Although the materials present similar mineralogical constitution, its particle size distribution and its consistency limits are considerably different. No direct relationship was found between porosity and hydraulic conductivity, however excellent relationships were found between the hydraulic conductivity and the fines contents, the clay fraction, the coarse fraction, the liquid limit and plasticity index. A geological model was obtained from data obtained from the drillings, the monitoring wells and the geophysical survey. The model revealed that the spatial distribution of the different materials is not uniform since the location of the layers and their thickness varies along the profile.

A conceptual site model (CSM) is simply a description of the environmental conditions at a contaminated site and surrounding area, which provides all interested parties with a vision of the site. CSM mainly identifies the source-pathway&amp / #8208 / receptor linkage to guide for effective site characterization, risk assessment and remedial investigations. Development of CSM is complicated because it is &lsquo / case specific&rsquo / and there is no single route to follow during decision making concerning the contaminated site. Moreover, type and extent of information needed varies according to size and level of contamination and site heterogeneity. The objective of this study is to develop a decision support tool that guides the site assessors during identification of possible decision routes that can be encountered / the procedure to be followed / and the information and data to be collected at each stage. This tool also introduces interactions between CSM andsampling strategies designed for various purposes. Developed decision support tool adapts to each specific contaminated site. Furthermore, a detailed review of sampling strategies is presented as a guidance for site assessors. The decision support tool is equipped with standardized tools used for CSM development, i.e. information/data collection forms, illustrative tools and exposure pathway diagram. Information on site, geology, hydrogeology, contamination source, contaminants and receptors is collected via CSM form. Illustrative tools may vary from very simple site sketches to very complex 3D drawings depending on the needs of the specific contamination cases. Exposure pathway diagram (EPD) is used to identify all transport mechanisms and potential exposure pathways. EPD is embedded into a user&amp / #8208 / friendly decision assistance tool based on Microsoft Excel and Visual Basic for Applications. The applicability and utility of the decision support tool was tested using two case studies. Case study applications indicated that the developed methodology satisfies the objectives aimed in this study.