Knowledge of geotechnical soil properties in the upper meter of the seabed is important for challenges such as scour around submerged structures, management of unexploded ordnances, and generally issues associated with active sediment transport and deposition. Portable free fall penetrometers have been previously used to provide initial information on sediment type, strength, and stratification, but challenges with the calibration of empirical parameters such as the cone factor and strain rate factor hampered the derivation of geotechnical design parameters such as undrained shear strength. This challenge applies particularly in areas of more rare seabed soil conditions such as very soft estuarine sediments. This study aims to advance the analysis procedure of portable free fall penetrometers (PFFP) in soft subaquatic fine-grained soils with natural water contents greater than the liquid limit by estimating the undrained shear strength (su). The logarithmic and power law methods for strain rate correction were investigated at sites in the York River Estuary and yielded a match to vane shear results at a logarithmic multiplier of k=0.1-0.3 and a power law rate exponent of β=0.01-0.03, indicating minimal strain rate effects. Resulting representative cone factors based on sediment strength and profile groupings ranged from 7 to 12 for logarithmic, power law, and no strain correction, and were tested at sites in the Potomac River with similar sediment properties. The PFFP su compared well with mini-vane shear measurements with differences of less than ± 0.5 kPa. Additionally, the PFFP su showed inappreciable differences in strength with or without strain rate application. Therefore, these high water content soils that exhibit little strain rate effects within a soil behavior context, can be better understood through rheological studies. Rheological studies were conducted, and the storage and loss modulus were observed to remain constant when the soil is tested over a range of frequencies. This indicates that the sediment strength is not affected by the rate of soil testing. The outcome of this study is the advanced the use of the PFFP by quantifying the strain rate effects and defining the applicable cone factors for use in estimating the undrained shear strength of soft estuarine marine soils. Furthermore, the understanding of soil behavior of these soils has been explored from rheological context. / Master of Science / Presence of unexploded munitions (UXO) in waterways and coastal environments poses a danger to the populace. UXOs located proud on the seabed can be moved by hydrodynamic forces such as waves and currents to habited areas. This has prompted the need to understand how UXOs interact with the seabed regarding erosion, burial, as well as sinking. Current methods used to detect munitions can lack accuracy from unknown seabed soil conditions. Portable free fall penetrometers (PFFP) are rapid and economical tools that are used to obtain soil information in the seabed. However, the interpretation of the penetrometer data needs to be advanced to get more accurate results of soil strength. In this research, physical soil samples were retrieved and tested in the laboratory. The laboratory results were used to calibrate the PFFP to improve the estimation of soil strength from PFFP. The estuarine soil tested exhibited high water contents raising the question of whether to describe its behavior rather as soil or suspension. Further tests were carried out to study how this soil deforms and flows when a load is applied. The results from this research enable the measuring of strength of the seabed more accurately and improves the understanding of very soft estuarine soil behavior.

Blast resistance has recently become increasingly relevant for structural engineers. Blast loads are created by explosive devices that, upon detonation, create pressure loads that are much higher than most that a structure would ever experience. While there are many types of blast loads that are impossible to adequately prepare for, methods are presently being developed to mitigate these loads. This research investigates the possibility of using synthetic fiber ropes as a means of blast resistance. This is the third phase of a multi-stage research endeavor whose goal is to analyze Snapping-Cable Energy Dissipators (SCEDs) for reducing the effects of large-scale lateral loads. Finite element models of portal frames were developed using the commercial finite element program ABAQUS and dynamic models were run for varying blasts and frame systems. Blast pressures of 100, 2,000, and 4,000 psi were applied to a steel portal frame and comparisons were made between unbraced frames and frames braced with springs of different stiffnesses. Additional tests were run to examine the effects of strain rate dependent yield on the results of the models. Parallel research is being conducted on the specific material behavior of the synthetic fiber ropes so that the models developed for this research can be revised for a more accurate determination of the effects of the ropes on structural systems subjected to blast loads. / Master of Science

Entre os objetivos da engenharia geotécnica está a busca pelo entendimento e previsão do comportamento mecânico dos solos. Para isso, existem basicamente duas abordagens: ensaios de laboratório ou ensaios de campo. Em cada obra o Engenheiro Geotécnico deve julgar quais são os métodos e procedimentos mais indicados de investigação, que resultarão em parâmetros confiáveis de projeto. Os ensaios de campo foram desenvolvidos baseados nos solos argilosos e arenosos em virtude dos comportamentos distintamente bem definidos, especialmente em termos de drenagem. O mesmo ocorre para o ensaio DMT, cuja execução e interpretação são influenciadas pelo tipo de solo e pelas condições de drenagem. O grande desafio, neste caso, está na interpretação dos ensaios em solos cuja solicitação ocorre sob condição de drenagem parcial, como nos casos de barragens de rejeito de mineração, ou em depósitos naturais de solos siltosos, onde esta condição pode levar a erros de interpretação. No DMT, a ocorrência de drenagem parcial influencia tanto na etapa de cravação da lâmina, quanto na etapa de expansão da membrana. Neste sentido, o foco deste trabalho está no problema da dissipação de poropressão durante a expansão da membrana, apresentando procedimentos especiais para realização do ensaio DMT. Serão apresentados dois métodos de interpretação de resultados, visando compensar os erros de interpretação causados pela dissipação parcial de poropressão: Método de Dissipação Completa e, Método de Dissipação Incompleta. Este trabalho foi desenvolvido baseado na realização de ensaios de campo, com uma campanha executada em solo brasileiro argiloso, que serviu de base à interpretação, sendo complementada por 6 ensaios realizados em diferentes sítios na Itália. Os resultados dos ensaios realizados pelo Método de Dissipação Completa foram interpretados através de duas abordagens: Método da Igualdade (analítico) e Método Simplificado. Enquanto a interpretação do Método de Dissipação Incompleta é permitida apenas através de procedimento simplificado. A análise paramétrica apresentou comportamentos similares entre ambas abordagens, demonstrando que a taxa de dissipação é o fator que mais influencia nos resultados. Ao final, os métodos foram aplicados e validados em diferentes locais, apresentando resultados adequados e compatíveis com o comportamento previamente definido através de outros ensaios. / Among the geotechnical engineering goals are the understanding and prediction of soil behavior. For this, there are basically two approaches: laboratory or in situ tests. In this case, the Geotechnical Engineer must judge the most appropriate investigation methods and procedures that will result in reliable design parameters. In situ tests were developed for clay and sand given to the fact that the behavior of these soils is well-defined and drainage conditions are properly controlled. The DMT is no exception, with test and interpretation methods influenced by the drainage conditions. The challenge resides in the interpretation of tests carried out in soils under partial-drainage conditions, such as tailings dams or natural deposits of silty soils, where partial-drainage conditions are taking place around the DMT blade leading to errors on its interpretation. The partial drainage condition influences both the DMT blade penetration phase and the membrane expansion phase. In this sense, this work focus on the problem of the pore pressure dissipation taking place simultaneously to membrane expansion. A non-standard procedure is proposed to sounding the DMT in silts that include two methods for DMT interpretation in order to compensate the errors caused by the partial pore pressure dissipation: Method of Complete Dissipation Curve and Method of Incomplete Dissipation Curve. This work was developed based on tests carried out in Brazilian clay soils to develop the proposed approach that was validated latter in non-standard tests carried out in different Italian sites. The results of the tests performed by the complete dissipation method were interpreted through two approaches: Equality Method (analytical) and Simplified Method, while the interpretation of the incomplete dissipation method is possible only through simplified procedure. The parametric analysis showed that these approaches yield similar results, demonstrating that the dissipation rate is the most important factor in the analysis. At the end, the methods were applied and validated at different sites, showing results that are compatible to previously defined behavior of the soils.

Pipeline ploughs are commonly used to bury offshore pipelines for their protection from loading by currents, damage from fishing trawler vessels and to provide thermal insulation to the line allowing the product to flow more efficiently. The rate of progress of pipeline ploughs in sand is complicated by a rate effect which causes the required tow force to increase drastically with velocity. In this research plough performance in sand is investigated by means of physical scale model tests. Scale model tests are the most practical method by which to conduct a parametric study on plough behaviour as full sized testing would be prohibitively expensive. Scale model tests also provide accurate control of sand conditions which allows investigation of the effect of soil parameters on plough behaviour. Model ploughs were manufactured at 50th, 25th and 10th scale so that scale effects could be explored. Each of the model ploughs had a detachable forecutter to allow its effect on plough performance to be observed. The forecutter was found to reduce the rate effect but increase the non-velocity dependant resistance of the plough. Ploughing tests were conducted at various relative densities in three sands of different permeability. The effects of ploughing rate on model plough behaviour under these various conditions was explored using an instrumented model plough, with particular attention paid to the resulting tow force. Results from the model ploughing tests were interpreted to determine the effect of permeability, relative density and plough depth on the tow forces generated during ploughing. The rate effect was found to increase strongly with reduction in permeability of the sand. Increasing the relative density of the sand was found to increase the rate effect but had little influence on the passive resistance of the plough. The test results were compared to an empirical model developed by Cathie and Wintgens (2001). New coefficients (Cw, Cs and Cd) have been proposed and therefore design procedures modified which may allow trenching contractors to make better predictions of plough performance in sands.

This thesis describes a new dynamic network model for imbibition which is based on a physically realistic description of the complex dynamics of corner film flow, swelling and snap-off. The model shows that film flow is a capillary driven non-linear diffusive process and that the competition between snapoff and frontal displacements is rate dependent and results in rate dependent relative permeabilities and residual saturations. In contrast to previously published models in which length scales for snap-off are either specified a priori or calculated assuming steady-state film flow and constant film conductivities, in the present model, snap-off arises as a natural consequence of the fully transient nature of film flow and swelling. The network model is used to analyse the complex interaction between displacement rate, contact angle, aspect ratio and pore and throat shape on relative permeability and residual saturation. Computed relative permeabilities and residual saturations are compared with laboratory measurements reported in the literature. It is concluded that the magnitude of the rate effect on imbibition relative permeabilities and residual saturations for a particular rock microstructure and wettability condition depends largely on the pore-throat aspect ratio. Higher aspect ratios result in stronger rate effects than do smaller aspect ratios.

This research takes a multidisciplinary approach to comprehensively investigate the material and mechanical properties as well as pore water chemistry of the Bearpaw shale. This made it possible to characterize how these properties relate to the mechanical strength of this material. The results of this research challenge our ideas of the hydrogeology and of the geological history of the region. Core samples of the Bearpaw Formation and the overlying glacial till were collected from a field site in southern Saskatchewan, Canada. A combination of laboratory tests including multi-staged oedometer tests, constant rate of strain oedometer tests, specialized triaxial swell tests, along with pore water chemistry and finite element modelling were used to meet the following objectives: (1) To investigate the material properties and compression behaviour of the Bearpaw in addition to assessing disturbance due to specimen size; (2) Examine the time dependent behaviour of the Bearpaw and the transferability of time rate models developed for soft soils to stiff soils; (3) Examine the swelling potential and behaviour of the Bearpaw Formation and the influence of boundary conditions on this behaviour, while assessing the applicability of the swell concepts developed for compacted materials to a naturally swelling clay material; and (4) Constrain the depositional age of the till overlying the Bearpaw Shale. Contrary to what is seen in soft soils, smaller sized specimens were found to reduce disturbance, and produce more accurate and consistent results. Creep was found to follow the same laws as it does in soft soils, calling into question whether the use of preconsolidation pressure to predict geological history in stiff clays is appropriate. There was significant variation in the observed swell pressures of samples of the same size and depth. Finally, the glacial till at site was found to belong uniquely to the Battleford Formation and ranges in age from 22,500 to 27,500 years which is much younger (over 100,000 years younger) than previously believed. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2010-01-29 01:34:14.071

Entre os objetivos da engenharia geotécnica está a busca pelo entendimento e previsão do comportamento mecânico dos solos. Para isso, existem basicamente duas abordagens: ensaios de laboratório ou ensaios de campo. Em cada obra o Engenheiro Geotécnico deve julgar quais são os métodos e procedimentos mais indicados de investigação, que resultarão em parâmetros confiáveis de projeto. Os ensaios de campo foram desenvolvidos baseados nos solos argilosos e arenosos em virtude dos comportamentos distintamente bem definidos, especialmente em termos de drenagem. O mesmo ocorre para o ensaio DMT, cuja execução e interpretação são influenciadas pelo tipo de solo e pelas condições de drenagem. O grande desafio, neste caso, está na interpretação dos ensaios em solos cuja solicitação ocorre sob condição de drenagem parcial, como nos casos de barragens de rejeito de mineração, ou em depósitos naturais de solos siltosos, onde esta condição pode levar a erros de interpretação. No DMT, a ocorrência de drenagem parcial influencia tanto na etapa de cravação da lâmina, quanto na etapa de expansão da membrana. Neste sentido, o foco deste trabalho está no problema da dissipação de poropressão durante a expansão da membrana, apresentando procedimentos especiais para realização do ensaio DMT. Serão apresentados dois métodos de interpretação de resultados, visando compensar os erros de interpretação causados pela dissipação parcial de poropressão: Método de Dissipação Completa e, Método de Dissipação Incompleta. Este trabalho foi desenvolvido baseado na realização de ensaios de campo, com uma campanha executada em solo brasileiro argiloso, que serviu de base à interpretação, sendo complementada por 6 ensaios realizados em diferentes sítios na Itália. Os resultados dos ensaios realizados pelo Método de Dissipação Completa foram interpretados através de duas abordagens: Método da Igualdade (analítico) e Método Simplificado. Enquanto a interpretação do Método de Dissipação Incompleta é permitida apenas através de procedimento simplificado. A análise paramétrica apresentou comportamentos similares entre ambas abordagens, demonstrando que a taxa de dissipação é o fator que mais influencia nos resultados. Ao final, os métodos foram aplicados e validados em diferentes locais, apresentando resultados adequados e compatíveis com o comportamento previamente definido através de outros ensaios. / Among the geotechnical engineering goals are the understanding and prediction of soil behavior. For this, there are basically two approaches: laboratory or in situ tests. In this case, the Geotechnical Engineer must judge the most appropriate investigation methods and procedures that will result in reliable design parameters. In situ tests were developed for clay and sand given to the fact that the behavior of these soils is well-defined and drainage conditions are properly controlled. The DMT is no exception, with test and interpretation methods influenced by the drainage conditions. The challenge resides in the interpretation of tests carried out in soils under partial-drainage conditions, such as tailings dams or natural deposits of silty soils, where partial-drainage conditions are taking place around the DMT blade leading to errors on its interpretation. The partial drainage condition influences both the DMT blade penetration phase and the membrane expansion phase. In this sense, this work focus on the problem of the pore pressure dissipation taking place simultaneously to membrane expansion. A non-standard procedure is proposed to sounding the DMT in silts that include two methods for DMT interpretation in order to compensate the errors caused by the partial pore pressure dissipation: Method of Complete Dissipation Curve and Method of Incomplete Dissipation Curve. This work was developed based on tests carried out in Brazilian clay soils to develop the proposed approach that was validated latter in non-standard tests carried out in different Italian sites. The results of the tests performed by the complete dissipation method were interpreted through two approaches: Equality Method (analytical) and Simplified Method, while the interpretation of the incomplete dissipation method is possible only through simplified procedure. The parametric analysis showed that these approaches yield similar results, demonstrating that the dissipation rate is the most important factor in the analysis. At the end, the methods were applied and validated at different sites, showing results that are compatible to previously defined behavior of the soils.

Entre os objetivos da engenharia geotécnica está a busca pelo entendimento e previsão do comportamento mecânico dos solos. Para isso, existem basicamente duas abordagens: ensaios de laboratório ou ensaios de campo. Em cada obra o Engenheiro Geotécnico deve julgar quais são os métodos e procedimentos mais indicados de investigação, que resultarão em parâmetros confiáveis de projeto. Os ensaios de campo foram desenvolvidos baseados nos solos argilosos e arenosos em virtude dos comportamentos distintamente bem definidos, especialmente em termos de drenagem. O mesmo ocorre para o ensaio DMT, cuja execução e interpretação são influenciadas pelo tipo de solo e pelas condições de drenagem. O grande desafio, neste caso, está na interpretação dos ensaios em solos cuja solicitação ocorre sob condição de drenagem parcial, como nos casos de barragens de rejeito de mineração, ou em depósitos naturais de solos siltosos, onde esta condição pode levar a erros de interpretação. No DMT, a ocorrência de drenagem parcial influencia tanto na etapa de cravação da lâmina, quanto na etapa de expansão da membrana. Neste sentido, o foco deste trabalho está no problema da dissipação de poropressão durante a expansão da membrana, apresentando procedimentos especiais para realização do ensaio DMT. Serão apresentados dois métodos de interpretação de resultados, visando compensar os erros de interpretação causados pela dissipação parcial de poropressão: Método de Dissipação Completa e, Método de Dissipação Incompleta. Este trabalho foi desenvolvido baseado na realização de ensaios de campo, com uma campanha executada em solo brasileiro argiloso, que serviu de base à interpretação, sendo complementada por 6 ensaios realizados em diferentes sítios na Itália. Os resultados dos ensaios realizados pelo Método de Dissipação Completa foram interpretados através de duas abordagens: Método da Igualdade (analítico) e Método Simplificado. Enquanto a interpretação do Método de Dissipação Incompleta é permitida apenas através de procedimento simplificado. A análise paramétrica apresentou comportamentos similares entre ambas abordagens, demonstrando que a taxa de dissipação é o fator que mais influencia nos resultados. Ao final, os métodos foram aplicados e validados em diferentes locais, apresentando resultados adequados e compatíveis com o comportamento previamente definido através de outros ensaios. / Among the geotechnical engineering goals are the understanding and prediction of soil behavior. For this, there are basically two approaches: laboratory or in situ tests. In this case, the Geotechnical Engineer must judge the most appropriate investigation methods and procedures that will result in reliable design parameters. In situ tests were developed for clay and sand given to the fact that the behavior of these soils is well-defined and drainage conditions are properly controlled. The DMT is no exception, with test and interpretation methods influenced by the drainage conditions. The challenge resides in the interpretation of tests carried out in soils under partial-drainage conditions, such as tailings dams or natural deposits of silty soils, where partial-drainage conditions are taking place around the DMT blade leading to errors on its interpretation. The partial drainage condition influences both the DMT blade penetration phase and the membrane expansion phase. In this sense, this work focus on the problem of the pore pressure dissipation taking place simultaneously to membrane expansion. A non-standard procedure is proposed to sounding the DMT in silts that include two methods for DMT interpretation in order to compensate the errors caused by the partial pore pressure dissipation: Method of Complete Dissipation Curve and Method of Incomplete Dissipation Curve. This work was developed based on tests carried out in Brazilian clay soils to develop the proposed approach that was validated latter in non-standard tests carried out in different Italian sites. The results of the tests performed by the complete dissipation method were interpreted through two approaches: Equality Method (analytical) and Simplified Method, while the interpretation of the incomplete dissipation method is possible only through simplified procedure. The parametric analysis showed that these approaches yield similar results, demonstrating that the dissipation rate is the most important factor in the analysis. At the end, the methods were applied and validated at different sites, showing results that are compatible to previously defined behavior of the soils.

A multi-functional (sensing -actuating) greenhouse ventilation window heated/cooled naturally by convection was designed to overcome different industry challenges in terms of designing smart applications. This ventilation window design includes a three-pulley system to reduce the load on the NiTi actuator and enhance its long-life time. In addition, using the NiTi actuator allows energy saving due to natural phase transformation induction (i.e. convection) and high force generation compared to the small NiTi wire mass. Structural analysis was used to determine the force generated in the “C-shaped” NiTi wire after loading. Transient thermal and structural analysis also was used to investigate the strain rate effects on the shape memory response of “C shaped” NiTi alloy element under different thermomechanical loadings and boundary conditions. Two types of loading have been applied isothermally or at adiabatic conditions. The results showed a significant effect of the high loading rates on increasing the stress plateau which is caused by the corresponding shift in the transformation temperatures. As a result, it could be expected that the actuator life time could be reduced when a rapid, as opposed to a slow loading rate, is adopted. In addition, the dynamic loading of the NiTi leads to a decrease of the recoverable strain. Experimental work was done to validate the simulation model by testing a commercial NiTi sample dynamically and compare the macroscopic displacement during mechanical loading and the strain recovery process.

In order to design more efficient and reliable structures, axial load tests are performed on foundation piles. Traditionally, static tests with an average duration of approximately twenty-four hours have been performed on test piles to obtain their axial capacity. These static tests require multiple piles used as anchors in addition to the test pile. Static tests are both expensive and time consuming. An alternative to static testing is dynamic testing which requires sophisticated interpretation, can damage the pile and may not produce accurate results. There is a relatively new testing method called the Statnamic Testing Method which tests foundation piles at a very fast rate, but still slower than with dynamic tests. As the rate at which load is applied to a test pile increases, the axial capacity also increases, particularly in clay. Research suggests that shear strength of soil typically increases 10% per log cycle increase in strain rate. Strain rate effects can vary widely and may be influenced by many factors including plasticity index, structure, ageing, overconsolidation ratio, temperature, etc. Statnamic testing was performed for this work. Nine static tests were performed on six different piles identical to the Statnamic test pile and driven through the same soil profile. The static tests had times to failure ranging from ten seconds to eighteen hours. Failure load increased by 13.7% per log cycle increase in velocity. Statnamic tests need more careful analysis when performed in clay to avoid over predicting pile capacity. A factor of 0.55 should be applied to Statnamic capacity to predict static capacity.