Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 54 for “"in situ stress"”.
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Determination of in situ stress in soil by hydraulic fracturing.
Massachusetts Institute of Technology. Dept. of Civil Engineering. Thesis. 1974. M.S.
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LABORATORY INVESTIGATION OF COAL PERMEABILITY UNDER REPLICATED IN SITU STRESS REGIME
… is a dynamic parameter impacted by changes in effective stress and desorption-induced "matrix shrinkage". Most commonly-used theoretical models developed to predict CBM production as a result of permeability changes are based on the assumption that the deformation of a depleting coalbed is …
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Multiscale determination of in situ stress and fracture properties in reservoirs
In this thesis we address the problem of determining in situ stress and fracture properties in reservoirs using borehole logs and surface seismic reflection data. The dissertation covers four subtopics. The first is the determination of horizontal stress magnitudes from measurements in a borehole. …
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The 3D in-situ stress field and its changes in geothermal reservoirs
Information on the contemporary in-situ stress state of the earth’s crust is essential for geotechnical applications and physics-based seismic hazard assessment. Yet, stress data records for a data point are incomplete and their availability is usually not dense enough to allow conclusive …
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Effect of Climate Change on Slope Stability of Variably Saturated Embankments Using Local Factor of Safety and In-Situ Stress Finite Element Analysis
… is actively underway and is expected to continue over the century. It has been predicted that the climate variables such as precipitation and potential evaporation will change significantly over the course of the century. Consequent changes in moisture content patterns within the earth …
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Investigation of In-Situ Stresses in Rocks via Acoustic Emission and the Kaiser Effect.
<p>This paper is a proposal for designing the Kaiser In‐Situ Stress (KISS) System. The KISS System’s goal is to determine in‐situ stresses in rock formations and other subsurface rocks by means of compression‐induced Acoustic Emission (AE) and the Kaiser effect. The KISS System is a non‐destructive …
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Effect of in-situ stresses on the stability of coal mine development workings
… problems associated with underground coal mining, those related to in-situ stresses are the most common ones affecting the safety of a mining operation. As a result, this has been the focus of many ground control research works done in the recent years. More work has been done in this thesis …
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Stress evolution during growth and atomic-scale surface structure effects in transition-metal thin films
Thin films are defined by an extremely high ratio of the in-plane dimensions to the thickness, resulting in very high surface-to-volume ratios. For this reason, the surface characteristics of a film play an important role in the properties of the film as a whole. This research focused on the …
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Impact of Stress-field Changes Induced by Hydraulic Fracturing on Subsurface Fault Stability
Hydraulic fracturing is essential for economically producing hydrocarbons from shale reservoirs, and thus has been extensively used in completion of shale gas wells. However, fracturing formations can change in-situ stresses in the surrounding areas. There are concerns that hydraulic fracturing may …
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3D Geomechanical Modeling of Shale Formations and its Application in Borehole Stabilization
The issue of borehole instability as seen in shale formation drilling is a major problem currently facing the industry. In recent years, deep exploration and more intensive development of hard and brittle shale gas reservoirs has shown that borehole instability is a widely occurring issue present …
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Effects of borehole stability on well log data
In this thesis we analyze the effects of borehole irregularities on well logs and develop methods to obtain reliable formation properties from such logs. Data from a well in eastern Venezuela are analysed. Borehole irregularities in this well consist mainly of borehole enlargements perpendicular to …
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Investigating the Influence of Mechanical anisotropy on the Fracturing Behaviour of Brittle Clay Shales with Application to Deep Geological Repositories
Clay shales are currently being assessed as possible host rock formations for the deep geological disposal of radioactive waste. However, one main concern is that the favourable long-term isolation properties of the intact rock mass could be negatively affected by the formation of an excavation …
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Ion assisted deposition of multicomponent thin films
A novel in-situ stress measurement technique to study the formation kinetics of multi component oxide thin films was developed and was applied to PbTiO₃. Single phase PbTi 0₃ thin films were formed from the reaction between films in the deposited PbO ITi0₂ multilayer. The film stoichiometry was …
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Kinetics and mechanisms of metal silicide formation
Kinetics and mechanisms of metastable (C49-TiSi$\sb2)$ and stable titanium disilicides (C54-TiSi$\sb2)$ have been investigated by thermally annealing Ti/polycrystalline Si bilayers using a combination of in situ sheet resistance measurement, in situ stress measurement, x-ray diffraction, …
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3D modeling and characterization of hydraulic fracture efficiency integrated with 4D/9C time-lapse seismic interpretations in the Niobrara Formation, Wattenberg field, Denver Basin
Hydrocarbon recovery rates within the Niobrara Shale are estimated as low as 2-8%. These recovery rates are controlled by the ability to effectively hydraulic fracture stimulate the reservoir using multistage horizontal wells. Subsequent to any mechanical issues that affect production from lateral …
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A comparative study on the structural behavior of concrete arch dams subjected to swelling due to aggregate sllica reactions
… a water-scarce country and this fact alone stresses the absolute need to preserve its water resources. As time goes by, the ageing of dams in South Africa is becoming an increasingly important factor to consider from a dam safety perspective. When considering concrete dams, Alkali Aggregate …
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Quantitative Comparison of Seismic Velocity Tomography With Seismic Activity Around a Deep Coal Longwall Panel
Mining induced seismicity can lead to bumps which cause problems at many mines within the United States and around the world. This seismicity, often referred to as bumps or bursts, can result in injuries, fatalities, and expensive capital damage and production interruptions. There are many factors …
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Crustal stress variability across spatial scales - examples from Canada, Northern Switzerland and a South African gold mine
The quantitative descriptions of the state of stress in the Earth’s crust, and spatial-temporal stress changes are of great importance in terms of scientific questions as well as applied geotechnical issues. Human activities in the underground (boreholes, tunnels, caverns, reservoir management, …
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Numerical simulation of viscoelastic buckle folds: Implications for stress, fractures, porosity and fluid flow
… simplifications are made, which may not result in realistic in-situ stress conditions leading to rock failure. This study represents the first numerical simulation of folding under the consideration of gravity and pore pressure to simulate the structural development of buckle folds.</p> <p>The …
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Analysis of the pressuremeter test by FEM formulation of the elasto-plastic consolidation
A decade has passed since the development of the self-boring pressuremeter (SBPM). Even though the device has been recognized by the geotechnical engineering profession as having high promise for evaluating in-situ stress-strain behavior of soils, its use is limited. In large part, this is due to …
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