<p>This dissertation studies the chemo-hygro-mechanical coupling involved in the process of crack propagation encountered both in natural and engineered context. Chemical processes are likely to affect the mechanical properties of geo-materials, resulting in possible weakening effect. The deformation and micro-cracking induced by material weakening in turn enhances the overall mass removal. In this study, several models within both elasticity and plasticity domain are developed for a better understanding of the enhanced crack propagation. A deformational plasticity model based on experimental observations is addressed. Rigid-plasticity models are applied to various boundary conditions. In the chemo-elasticity model, chemical dissolution is assumed to be a function of a comprehensive strain invariant. One-way coupling and two-way coupling models are discussed. In the two-way coupling model, volumetric strain coupling and deviatoric strain coupling are compared. A variety of loading modes are adopted to investigate the chemical enhancement of propagation of a single crack. The behavior of the material is either rigid-plastic, or elastic with the variable of mass removal enters the constitutive equation as a chemical strain. Comparison between the results from two models is presented and discussed.</p> / Dissertation

Depositional processes are the most critical, complicated conditions that govern sediment properties and their variations, which in turn significantly affect the geotechnical behavior of the sediment. The complexity of depositional and post-depositional processes, which results in a variety of depositional environments, makes constructing a plausible model for the consolidation process of sediments difficult. The mutual influence between the temporal and spatial variation of depositional environments with their resultant physical and mechanical properties cause several compression issues, such as consolidation settlement and land subsidence, which mostly occur in estuarine-riverine regions throughout the world. The first aim of this study is proposing a new grain-size based scheme to classify unconsolidated inorganic sediments that cover a wide range of natural depositional environments with a special emphasis on fine-grained deposits. The proposed classification depends on the linear relationship between percent Fines and the silt fraction. By combining grain size characteristics and plasticity, the proposed scheme provides further characterization of depositional environments. The proposed scheme extends the utility of the scheme beyond simply classifying the sediment class, towards inferring the potential mechanical behavior of sediments having various Grain Size Distribution (GSD) proportions and mineralogy. Addressing elastic wave properties as a geotechnical parameter, in particular, shear wave velocities to determine the mechanical behavior of sediments is because is strongly influenced by the change in those physical state properties during compression and cementation processes. This study presents a continuous function that explicitly uses shear wave velocity to predict the non-linear function of consolidation process (e -log p'), This approach also defines factors that describe the depositional environment, such as grain size and plasticity limits. These factors are shown to influence and control the e -log p' relationship. Thus, the resulting function is shown to be applicable to a variety of sedimentary materials. Also, in this dissertation, elastic shear-wave velocity under critical state framework was employed. A shear wave-based constitutive model was developed that is able to predict the stress-strain behavior of a normally consolidated sediments, under undrained loading. A new power-type relationship that predicts the shear strength behavior and critical stress paths of fine-grained sediments under undrained conditions. Also, it investigates the reliability of the link between input model parameters with the basic properties of a variety of fine-grained sediments. As importance of measuring of elastic wave velocities, a number of soil tests performed during particular construction stages can be reduced and compensated. This reduces the cost of evaluating the stability level, monitoring stress path distributions, and determining undrained shear strength behavior during particular stages of the construction process. The study also provides correlations that can be applied in various fine-grained depositional environments that have weak, fine-grained soil layers, on which the constructions are built.

Coupled Thermal-Hydrological-Mechanical-Chemical (THMC) processes that exist in the development of different geo-resources (e.g. deep geothermal and shale gas) affect the fracture response (i.e. aperture and permeability), which in turn influences the reservoir production. The main goal of this study was to experimentally evaluate the impact of THMC processes on the response of rock specimens relevant for deep geothermal and shale gas formations. The effects of THMC processes were investigated on: (i) success of the hydraulic fracturing/hydro-shearing mechanism during stimulation stage, and (ii) closure of the created network of fractures during production stage. The elastic, cyclic, creep, and failure characteristics of different intact reservoir rocks in both short- and long-term were investigated to evaluate their response in stimulation stage. In addition, a series of flow tests on fractured reservoir cores were conducted to evaluate how THMC processes affect fracture response subjected to different stress levels, temperatures, composition of injected fluid, and injection rate. Moreover, the sensitivity of ultrasonic signatures (i.e. velocity, amplitude, attenuation, and time-frequency content) to (i) microstructural changes in the intact rocks, and (ii) flow-induced alterations of aperture/permeability in the fractured rocks were investigated. Analysis of hydraulic data, chemical composition of the effluent, ultrasonic signatures, and X-Ray micro-CT and SEM images, provided invaluable information that facilitated interpretation of the effects of coupled THMC processes on fracture response.

A combined geological and rock mechanics approach to tunnel face behaviour prediction, based on improved understanding of brittle fracture processes during TBM excavation, was developed to complement empirical design and performance prediction for TBM tunnelling in hard rock geological conditions. A major challenge of this research was combining geological and engineering terminology, methods, and objectives to construct a unified Geomechanical Characterisation Scheme. The goal of this system is to describe the spalling sensitivity of hard, massive, highly stressed crystalline rock, often deformed by tectonic processes. Geological, lab strength testing and TBM machine data were used to quantify the impact of interrelated geological factors, such as mineralogy, grain size, fabric and the heterogeneity of all these factors at micro and macro scale, on spalling sensitivity and to combine these factors within a TBM advance framework. This was achieved by incorporating aspects of geology, tectonics, mineralogy, material strength theory, fracture process theory and induced stresses. Three main approaches were used to verify and calibrate the Geomechanical Characterisation Scheme: geological and TBM data collection from tunnels in massive, highly-stressed rock, interpretation of published mineral-specific investigations of rock yielding processes, and numerical modelling the rock yielding processes in simulated strength tests and the TBM cutting process. The TBM performance investigation was used to identify the mechanism behind the chipping processes and quantify adverse conditions for chipping, including tough rock conditions and stress induced face instability. The literature review was used to identify the critical geological parameters for rock yielding processes and obtain strength and stiffness values for mineral-specific constitutive models. A texture-generating algorithm was developed to create realistic rock analogues and to provide user control over geological characteristics such as mineralogy, grain size and fabric. This methodology was applied to investigate the TBM chipping process to calibrate the Geomechanical Characterisation Scheme. A Chipping Resistance Factor was developed to combine the quantified geological characteristic factors and laboratory strength values to predict conditions with high risk of poor chipping performance arising from tough rock. A Stress-Related Chip Potential Factor was developed to estimate conditions with high risk of advance rate reduction arising from stress-induced face instability. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2008-09-25 23:58:58.071

abstract: Rotorcraft operation in austere environments can result in difficult operating conditions, particularly in the vicinity of sandy areas. The uplift of sediment by rotorcraft downwash, a phenomenon known as brownout, hinders pilot visual cues and may result in a potentially dangerous situation. Brownout is a complex multiphase flow problem that is not unique and depends on both the characteristics of the rotorcraft and the sediment. The lack of fundamental understanding constrains models and limits development of technologies that could mitigate the adverse effects of brownout. This provides the over-arching motivation of the current work focusing on models of particle-laden sediment beds. The particular focus of the current investigations is numerical modeling of near-surface fluid-particle interactions in turbulent boundary layers with and without coherent vortices superimposed on the background flow, that model rotorcraft downwash. The simulations are performed with two groups of particles having different densities both of which display strong vortex-particle interaction close to the source location. The simulations include cases with inter-particle collisions and gravitational settling. Particle effects on the fluid are ignored. The numerical simulations are performed using an Euler- Lagrange method in which a fractional-step approach is used for the fluid and with the particulate phase advanced using Discrete Particle Simulation. The objectives are to gain insight into the fluid-particle dynamics that influence transport near the bed by analyzing the competing effects of the vortices, inter-particle collisions, and gravity. Following the introduction of coherent vortices into the domain, the structures convect downstream, dissipate, and then recover to an equilibrium state with the boundary layer. The particle phase displays an analogous return to an equilibrium state as the vortices dissipate and the boundary layer recovers, though this recovery is slower than for the fluid and is sensitive to the particle response time. The effects of inter-particle collisions are relatively strong and apparent throughout the flow, being most effective in the boundary layer. Gravitational settling increases the particle concentration near the wall and consequently increase inter-particle collisions. / Dissertation/Thesis / M.S. Aerospace Engineering 2011

City zoning map of Elizabethton, Tennessee prepared in December 1966 by the Tennessee State Planning Commission from subdivision plats and soil conservation aerial photographs. The preparation of this map was financially aided through a federal grant from the U.S. Department of Housing and Urban Development, under the Urban Planning Assistance Program authorized by Section 701 of the House Act of 1954, as amended. The city's major roads, railroads and waterways are labeled. There is slight water damage on the right side of the map which led to the discoloration. According to the Tennessee State Depository stamp, this zoning map became part of the Sherrod Library depository collection on March 18, 1986. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. / https://dc.etsu.edu/rare-maps/1009/thumbnail.jpg

Current methods of production forecasting such as decline curve analysis (DCA) or numerical simulation require years of historical production data, and their accuracy is limited by the choice of model parameters. Unconventional resources have proven challenging to apply traditional methods of production forecasting because they lack long production histories and have extremely variable model parameters. This research proposes a data-driven alternative to reservoir simulation and production forecasting techniques. We create a proxy-well model for predicting cumulative oil production by selecting statistically significant well completion parameters and reservoir information as independent predictor variables in regression-based models. Then, principal component analysis (PCA) is applied to extract key features of a well’s time-rate production profile and is used to estimate cumulative oil production. The efficacy of models is examined on field data of over 400 wells in the Eagle Ford Shale in South Texas, supplied from an industry database. The results of this study can be used to help oil and gas companies determine the estimated ultimate recovery (EUR) of a well and in turn inform financial and operational decisions based on available production and well completion data.

O objetivo do presente estudo foi demonstrar que as informações produzidas pelos trabalhos científicos, quando organizadas e colocadas em formato eletrônico (digital), facilitam a utilização por pessoas a quem venham interessar. Foi desenvolvido um projeto em mapeamento geotécnico, utilizando-se um sistema de informação geográfica e um projeto dentro do ambiente de uma linguagem de programação(elaboração de um aplicativo). Observou-se que esses instrumentos proporcionam facilidade e rapidez na manipulação, na busca, no armazenamento, na visualização, na consulta e na análise da informação. A Pesquisa teve lugar na região de Ribeirão Preto (SP) e, utilizando-se o desenvolvimento do projeto de mapeamento geotécnico na escala 1:50.000 (escala regional), foi feita a análise das formas de organização das informações no formato eletrônico considerando o sistema de informação geográfica e usando um aplicativo externo ao SIG. Puderam- e verificar vantagens e desvantagens do uso desses instrumentos, em relação ao formato não-eletrônico (e forma de papel). Além do SIG (SPRING4.0, desenvolvido pelo Instituto Nacional de Pesquisas Espaciais – INPE) e o aplicativo desenvolvido na linguagem de programação Visual Basic (comercializada pela Microsoft), recorreu- e a um visualizador de informações georeferenciadas (TERRAVIEW, desenvolvido pelo INPE) e um programa (um anplet SPRINGWEB, desenvolvido pelo INPE) que ajuda a disponibilizar as informações na Internet. Ficou comprovado que a informação armazenada eletronicamente é mais fácil de ser manipulada, organizada e consultada. / This research had proposed to show that the information produced by scientific jobs, when this information is organized and electronically, this facilitated the use for other interested people. Therefore, a geological engineering mapping design was developed using a geographical information system (GIS) and another project about the elaboration computer program. It was observed that theese tools proposed easier and faster manipulation, search, storage, display, reference and the analysis of geo-referential information. The research was realized in Ribeirão Preto and region in the state of São Paulo, using the development of the geological engineering mapping desing on a scale of 1:50,000 (regional scale). Analyse of the ways of organizing of the information electronically: in GIS and using a computer program apart from GIS. You can verify the advantages and disadvantages when using these tools on paper as well. In addition to using GIS (SPRING, it was developed by Instituto de Pesquisas Espaciais - INPE) and the computer program, in this research which was developed in Visual Basic (it was sold by Microsoft), a displayer for geo-referential information (TERRAVIEW, it was developed by INPE) and a software were also used, wich offers the visualization of the information in the internet (SPRINGWEB is an anplet which was developed by INPE). And it proved that the electronically stored information is easier to be manipulated, visualized, organized and consulted

Master of Science / Department of Civil Engineering / Stacey Kulesza / In Kansas, mechanically stabilized earth (MSE) retaining walls are typically backfilled with coarse aggregate. Current backfill material testing procedures used by the Kansas Department of Transportation (KDOT) utilize on-site observations for construction quality assurance and the American Association of State Highway and Transportation Officials standard T 288-12 (“Standard Method of Test for Determining Minimum Laboratory Soil Resistivity”). AASHTO T 288-12 is designed to test a soil sample’s electrical resistivity (ER) that correlates to its corrosion potential. However, the test, based on material passing through a No. 10 sieve, is inappropriate for coarse aggregate typically used by KDOT as the aggregate will be retained on a No. 10 sieve and potentially leads to over-conservative designs. However, ER imaging provides a two-dimensional (2D) profile of bulk ER of backfill material, thereby yielding more information regarding backfill uniformity compared to traditional sampling. The objective of this study was to characterize bulk ER of in-place MSE wall backfill aggregate. In this study, MSE walls selected by KDOT were tested using ER imaging during construction to determine bulk ER of the backfill. Variations within backfill ER may be a result of varying aggregate material, inclusions of fines, thoroughness of compaction, and the presence of water. ER imaging was used on five walls: four MSE walls and one gravity retaining wall that contained no reinforcement. One MSE wall contained metal reinforcement, while the other four walls contained geosynthetic. The ER imaging field method produced a 2D profile that depicted ER uniformity for bulk analysis. A post processing algorithm was generated to remove the subjective nature of the ER imaging results. The program determines the bulk ER based upon the ER imaging results. These results indicate that the laboratory analysis of AASHTO T 288-12 under-estimates the bulk ER of in-situ backfill material. Identification of a material’s bulk ER will help characterize the ER of aggregates in a complementary KDOT project. Results of this study will be used to recommend an in-situ test method for aggregate used by KDOT.

abstract: Shallow earthquakes in the upper part of the overriding plate of subduction zones can be devastating due to their proximity to population centers despite the smaller rupture extents than commonly occur on subduction megathrusts that produce the largest earthquakes. Damaging effects can be greater in volcanic arcs like Java because ground shaking is amplified by surficial deposits of uncompacted volcaniclastic sediments. Identifying the upper-plate structures and their potential hazards is key for minimizing the dangers they pose. In particular, the knowledge of the regional stress field and deformation pattern in this region will help us to better understand how subduction and collision affects deformation in this part of the overriding plate. The majority of the upper plate deformation studies have been focused on the deformation in the main thrusts of the fore-arc region. Study of deformation within volcanic arc is limited despite the associated earthquake hazards. In this study, I use maps of active upper-plate structures, earthquake moment tensor data and stress orientation deduced from volcano morphology analysis to characterize the strain field of Java arc. In addition, I use sandbox analog modeling to evaluate the mechanical factors that may be important in controlling deformation. My field- and remotely-based mapping of active faults and folds, supplemented by results from my paleoseismic studies and physical models of the system, suggest that Java’s deformation is distributed over broad areas along small-scale structures. Java is segmented into three main zones based on their distinctive structural patterns and stress orientation. East Java is characterized by NW-SE normal and strike-slip faults, Central Java has E-W folds and thrust faults, and NE-SW strike-slip faults dominate West Java. The sandbox analog models indicate that the strain in response to collision is partitioned into thrusting and strike-slip faulting, with the dominance of margin-normal thrust faulting. My models test the effects of convergence obliquity, geometry, preexisting weaknesses, asperities, and lateral strength contrast. The result suggest that slight variations in convergence obliquity do not affect the deformation pattern significantly, while the margin shape, lateral strength contrast, and perturbation of deformation from asperities each have a greater impact on deformation. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2016