Characterizing Aquitard Properties from the response of Grouted Vibrating Wire Piezometers to Surface Loading

Barometric Response Functions (BRF) are used to characterize the observed pore pressure response within grouted-in vibrating wire piezometers to changes in surface barometric pressure. The BRF facilitates determination of loading efficiency (λLE) which is a function of in situ compressibility. However, the mechanisms which control the characteristic shape of a BRF within a fully grouted borehole are not well understood. In this study, the transient pore pressure responses to both local instantaneous loading and transient barometric loading are used to improve our understanding of the BRF response. Two boreholes were each drilled to a depth of 200 m in a thick clay sequence in Southern Saskatchewan. One borehole was advanced through continuous coring while the other was drilled using rotary fluid circulation. Ten vibrating-wire piezometers (VWPs) were placed within each borehole at a 10m spacing. The pore pressure in all VWPs and barometric pressure was recorded concurrently for 3 years following installation. Multiple-linear regression was undertaken on both data sets to determine the BRF for each VWP. In addition, localized instantaneous surface loading was applied using heavy construction equipment. The coupled load-pore responses were simulated using a commercial coupled stress and water flow finite element model to evaluate the grout and formation hydraulic and mechanical properties. The BRF characteristics of the monitored depth profile were used to identify the limitations of linear-regression methods for determining λLE. Near-borehole influences, such as stress-release induced damage or mud filter-cake build-up, can influence the magnitude and timing of observed pore pressures. These limitations can be addressed by judicious selection of drilling methods, grouting procedures, and pressure sensor resolution. In addition, a more rigorous interpretation of the BRF can be used to obtain additional information about the in situ hydraulic and geomechanical properties of the aquitard. The rigorous analysis of measured pore pressure response to changes in external stress improves our understanding of in situ properties and the behavior of low-hydraulic conductivity and low-compressibility formations

Characterizing Aquitard Properties from the response of Grouted Vibrating Wire Piezometers to Surface Loading

Barometric Response Functions (BRF) are used to characterize the observed pore pressure response within grouted-in vibrating wire piezometers to changes in surface barometric pressure. The BRF facilitates determination of loading efficiency (λLE) which is a function of in situ compressibility. However, the mechanisms which control the characteristic shape of a BRF within a fully grouted borehole are not well understood. In this study, the transient pore pressure responses to both local instantaneous loading and transient barometric loading are used to improve our understanding of the BRF response. Two boreholes were each drilled to a depth of 200 m in a thick clay sequence in Southern Saskatchewan. One borehole was advanced through continuous coring while the other was drilled using rotary fluid circulation. Ten vibrating-wire piezometers (VWPs) were placed within each borehole at a 10m spacing. The pore pressure in all VWPs and barometric pressure was recorded concurrently for 3 years following installation. Multiple-linear regression was undertaken on both data sets to determine the BRF for each VWP. In addition, localized instantaneous surface loading was applied using heavy construction equipment. The coupled load-pore responses were simulated using a commercial coupled stress and water flow finite element model to evaluate the grout and formation hydraulic and mechanical properties. The BRF characteristics of the monitored depth profile were used to identify the limitations of linear-regression methods for determining λLE. Near-borehole influences, such as stress-release induced damage or mud filter-cake build-up, can influence the magnitude and timing of observed pore pressures. These limitations can be addressed by judicious selection of drilling methods, grouting procedures, and pressure sensor resolution. In addition, a more rigorous interpretation of the BRF can be used to obtain additional information about the in situ hydraulic and geomechanical properties of the aquitard. The rigorous analysis of measured pore pressure response to changes in external stress improves our understanding of in situ properties and the behavior of low-hydraulic conductivity and low-compressibility formations

Characterizing Aquitard Properties from the response of Grouted Vibrating Wire Piezometers to Surface Loading

Barometric Response Functions (BRF) are used to characterize the observed pore pressure response within grouted-in vibrating wire piezometers to changes in surface barometric pressure. The BRF facilitates determination of loading efficiency (λLE) which is a function of in situ compressibility. However, the mechanisms which control the characteristic shape of a BRF within a fully grouted borehole are not well understood. In this study, the transient pore pressure responses to both local instantaneous loading and transient barometric loading are used to improve our understanding of the BRF response. Two boreholes were each drilled to a depth of 200 m in a thick clay sequence in Southern Saskatchewan. One borehole was advanced through continuous coring while the other was drilled using rotary fluid circulation. Ten vibrating-wire piezometers (VWPs) were placed within each borehole at a 10m spacing. The pore pressure in all VWPs and barometric pressure was recorded concurrently for 3 years following installation. Multiple-linear regression was undertaken on both data sets to determine the BRF for each VWP. In addition, localized instantaneous surface loading was applied using heavy construction equipment. The coupled load-pore responses were simulated using a commercial coupled stress and water flow finite element model to evaluate the grout and formation hydraulic and mechanical properties. The BRF characteristics of the monitored depth profile were used to identify the limitations of linear-regression methods for determining λLE. Near-borehole influences, such as stress-release induced damage or mud filter-cake build-up, can influence the magnitude and timing of observed pore pressures. These limitations can be addressed by judicious selection of drilling methods, grouting procedures, and pressure sensor resolution. In addition, a more rigorous interpretation of the BRF can be used to obtain additional information about the in situ hydraulic and geomechanical properties of the aquitard. The rigorous analysis of measured pore pressure response to changes in external stress improves our understanding of in situ properties and the behavior of low-hydraulic conductivity and low-compressibility formations

Análise de sensibilidade do modelo de Caprio para simulação de evolução de resistência de pragas a toxinas BT.

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Professor Pimenta Claro (1957-2018): Pioneer in dynamics of mechanical systems at the University of Minho

This work highlights the importance of Professor Pimenta Claro in the genesis and development of a new scientific area at the Department of Mechanical Engineering of the University of Minho, namely Dynamics of Mechanical Systems. Professor Pimenta Claro initiated his academic career in October 1980, coming from industry, where he was a well-recognized engineer in the field of mechanical design. Professor Pimenta Claro concluded his Pedagogical Aptitude and Scientific Capacity Tests (PAPCC) – MSc equivalent – in 1987, with dissertation title “Estudo Comparativo das Previsões Teóricas do Desempenho de Chumaceiras Radiais Hidrodinâmicas com Resultados Experimentais”. Professor Pimenta Claro received his doctorate degree in 1994 with thesis “Reformulação de Método de Cálculo de Chumaceiras Radiais Hidrodinâmicas – Análise do Desempenho Considerando Condições de Alimentação” under the mentorship of Professor Sousa Miranda, which was in fact the first PhD in Mechanical Engineering defended at the University of Minho. In 1997, Professor Pimenta Claro broken with his past background – classical tribology – to open a new research domain – Dynamics of Mechanical Systems. Since then, Professor Pimenta Claro has coordinated and participated in several scientific projects both with national and international partners, as well as projects with industrial partners. Professor Pimenta Claro was author of numerous publications, including scientific papers, books, conference papers, etc., and supervised PhD and MSc students. From 2007 to 2013 he coordinated the research group called Dynamics of Mechanical Systems. Professor Pimenta Claro was also pioneer and responsible for the creation of new courses on dynamics of mechanical systems offered in different degrees at the School of Engineering of the University of Minho. Thus, the main purpose of this work is to highlight Pimenta Claro’s contributions to the vast scientific area of Dynamics of Mechanical Systems at the Department of Mechanical Engineering of the University of Minho

T.09 - Dinâmica de engrenagens

Neste documento aborda-se o tema da dinâmica de engrenagens, o qual é lecionado no âmbito da unidade curricular Órgãos de Máquinas II, do curso de Mestrado Integrado em Engenharia Mecânica da Universidade do Minho. Com efeito, inicia-se este assunto com uma breve abordagem ao conceito de diagrama do corpo livre e nomenclatura em dinâmica de engrenagens. Seguidamente apresenta-se a análise dinâmica de engrenagens cilíndricas de dentes retos e inclinados, engrenagens cónicas e de parafuse sem-fim. Finalmente, termina-se este documento com uma breve lista de questões de revisão de conhecimentos, assim como uma lista de referências bibliográficas.info:eu-repo/semantics/publishedVersio

Experimental evaluation of cohesive laws components of mixed-mode I + II fracture characterization of cortical bone

Mixed-mode I + II fracture characterization of cortical bone tissue is addressed in this work. The mixed-mode bending test was used to impose different mode ratios. An equivalent crack length data reduction method was considered to obtain the strain energy release rate components. Crack opening and shear displacements were measured by means of digital image correlation. These quantities were then integrated to propose a direct evaluation of cohesive laws. The components of the cohesive laws for each mixed-mode loading were obtained by the uncoupled and Hogberg ¨ ’s methods. The later provided consistent evolution of strain energy release rate and peak stresses components in function of mode-ratio, revealing its appropriateness regarding the fracture characterization of cortical bone under mixed-mode I + II loading.The first and second author acknowledges the Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020. The third and fifth authors acknowledge the ‘Laboratorio' Associado de Energia, Transportes e Aeronautica’ (LAETA) for the financial support by the project UID/EMS/50022/2019 and the financing of FCT/MCTES through national funds (PIDDAC) and UIDB/00667/2020 (UNIDEMI). The fourth author acknowledges the Portuguese Foundation for Science and Technology, under the project PTDC/EME-SIS/28225/2017