Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1983. / Includes bibliographical references (leaves 91-93).

Limits of slope stability, limit equilibrium methods, and of the finite element code FEADAM are reached in the application of these methods to the problem of cracked dams constructed on collapsing soils.

Thesis (M.Eng.)--University of Wollongong, 2005. / Typescript. Includes bibliographical references: leaf 101-108.

Thesis (M.App.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 165-175). Also available in electronic format on the Internet.

Thesis (M. Eng.(Geotechnical Engineering))--University of Pretoria, 2003. / Includes bibliographical references.

A vast amount and variety of mine tailings are produced around the world each day. In the gold¬mining industry in South Africa the residue of crushed are is disposed of in large tailings or hydraulic fill dams. The outer walls of these dams are built up of layers of material, each of which is allowed to dry before the next layer is placed. In order to study the stability of these walls, the appropriate engineering properties of the tailings must be ascertained. Due to the construction technique used in tailings dam construction, the outer walls are in an unsaturated state, which also means that suctions are generated within the tailings. Various techniques exist to measure suction, most of which are indirect methods. The recent development of the mid-¬plane suction probe at the University of Pretoria created the opportunity of measuring suctions directly on desiccating samples of gold mine tailings. A test method has been developed from which soil mechanics parameters can be derived from suction measurements. The experimental programme consisted of a series of these newly developed tests on fine and coarse samples of gold mine tailings, as well as on different particle size ranges. The experimental results were used in the development of a new method of predicting the air-entry value, with only the grading of the tailings known. A new method of predicting the soil-water characteristic curve up to the air-entry value was also proposed. The results of the research showed that the tailings remain saturated up to the air-entry value. The clay, fine silt and medium silt sized tailings was found to be the controlling particle size ranges in the development of suctions. The vast amount of parameters and information gained through the use of the proposed test method clearly indicates its effectiveness in studying the performance and characteristics of a material drying from saturation. The results also indicated the effectiveness of the mid-plane suction probe for the direct measurement of suction. / Dissertation (M Eng (Geotechnical Engineering))--University of Pretoria, 2006. / Civil Engineering / unrestricted

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 60-61. / by Gregory Paul Matthews. / M.S.

An investigation into the transient impacts of flood loadings on earthen embankments was conducted. Two embankments were instrumented and monitored over a period of four years. One of these embankments was a levee located along the Mississippi River just north of Cairo, Illinois. The other embankment was part of a catchment basin at the Engineer Research and Development Center located in Vicksburg, MS. Tensiometer and porous block sensors were used to monitor the pore water pressures in the embankments. It was found that when measuring the field soil water retention, tensiometers were more responsive than porous block sensors at low suctions; although, at shallower depths, the tensiometer performance was limited during periods of extended drying. It was shown that during the start of flooding, pore water pressures in the embankment soils were near −10 kPa at depths less than 2 m, which was greater than the normally assumed hydrostatic conditions. An investigation into flood hydrographs collected from across the United States showed that flood durations could be hundreds of days long. These hydrographs were collected over a period of 10 years. It was found that the recorded peak flood stage exceeded the major flood stage 11% of the time. An uncouple transient seepage model of a 2015 Mississippi River flood event that occurred at the Cairo levee showed that an uncoupled model could simulate the field measurements; however, the material properties that resulted in the most accurate simulation differed from those measured in the laboratory. Soil water retention characteristics of the embankment soils were assessed, and it was found that laboratory measured soil water retention curves could be used to bracket field measurements. Slope stability analyses were performed as a proxy to assessing the progression of the wetting front in the levees. Accounting for the increase in shear strength due to the presence of matric suction resulted in minimal impacts to stability factors of safety for levee embankments during flood loadings. The results of this investigation will help to improve the reliability of transient seepage analyses and provides guidance for future embankment monitoring investigations. / Doctor of Philosophy / An investigation into the movement of flood water through flood control embankments was conducted. Typically, analysis of this phenomenon is performed independent of the effects of time. For this investigation, the impacts of time were considered. When considering the effects of time dependent loadings, an initial distribution of water pressures must be considered. Typical assumptions regarding these distributions were investigated using four years of sensor measurements from two embankments. These measurements were also used to investigate appropriate material properties when considering saturated and unsaturated soil properties necessary for these analyses. Results show that typical assumptions may not be appropriate regarding initial water pressure distributions. Additionally, recommendations for assigning material properties were provided and it was found that these types of analyses can simulate flood loadings, but a range of material properties must be explored to understand the full range of performance. The impact of these results will lead to better predictions of embankment performance during flood loadings.

[pt] A análise das condições de fluxo na barragem de Curuá-Una (Pará) tem como objetivo avaliar a viabilidade geotécnica quanto à elevação do nível de operação do reservatório. A Usina de Curuá-Una (operada pela REDE Celpa) é responsável pelo abastecimento elétrico de Santarém. No entanto, nos horários de grande consumo, a produção de energia tem se mostrado insuficiente. O alteamento do reservatório de Curuá-Una é uma alternativa para o aumento de geração energética. Curuá-Una destaca-se por ser fundada em terreno arenoso, solução poucas vezes utilizada no mundo. A barragem de terra é do tipo zonada, com altura máxima de 26m e comprimento de 600m. Os parâmetros geotécnicos necessários para as análises do presente trabalho foram obtidos em ensaios de laboratório, em informações referentes à construção e em dados de instrumentação durante a operação da barragem. As análises numéricas foram realizadas com o programa FLOW3D. A retroanálise do regime de fluxo, feita com base na piezometria, possibilitou a estimativa das permeabilidades dos diversos materiais. A partir destes dados foi possível simular as poropressões associadas a diferentes níveis do reservatório. Foram definidos três níveis de alerta (normal, atenção e emergência) referentes à segurança da barragem. As análises indicam que a barragem opera atualmente dentro do nível normal e que um alteamento de 1,5m do reservatório não afeta a condição de segurança. O aumento das subpressões na base da barragem foi também avaliado, com os resultados mostrando um incremento máximo de 5 por cento. / [en] The analysis of flow conditions in Curuá-Una Dam, State of Pará, has the objective of evaluating the geotechnical feasibility of raising the operation level of the reservoir. Curuá-Una Power Plant, operated by REDE Celpa, is responsible for the electric supply of Santarém city. However, in periods of peak consumption, the energy production has been insufficient. Raising of Curuá-Una reservoir is an attractive alternative for increasing energy production. Curuá-Una Dam is distinguished for being constructed on sandy alluvial soil, which is a solution rarely used in the world. The earth dam is zoned, with maximum height of 26m and crest length of 600m. The geotechnical parameters were obtained from laboratory tests, field instrumentation data and construction reports. The numerical analyses were carried out with FLOW3D program. A back-analysis of flow behavior was performed for evaluating permeability parameters, taking into account results from piezometers installed in the dam and in the foundation materials. These parameters were used to predict pore pressures associated to different reservoir levels. Three levels of alert conditions (normal, attention and emergency) referring to the safety of the dam have been defined. The analyses indicated that the dam is operating within normal levels and a 1.5m rising of the reservoir shall not affect dams safety. The uplift pressures, due to different reservoir levels, have also been evaluated, with results showing a maximum increment of 5 percent.

A comprehensive experimental program dealing with three-dimensional overtopping and breach development as well as two-dimensional overtopping physical tests of noncohesive earth embankments has been conducted on scale models in the Hydraulic Laboratory at the Department of Civil Engineering at the University of Ottawa. The experimental program which consisted of three phases focused on geotechnical and hydraulic aspects of the embankment breach mechanism. The first two phases focused on two test series for the three-dimensional breach overtopping tests: drainage and compaction. The test series were designed to determine the embankment breach characteristics using test parameters which have not been adequately identified or controlled in past noncohesive physical models: initial soil-water state and optimum dry unit weight. Both parameters were controlled in laboratory tests by means of compaction effort and seepage through the embankment body, respectively. The dynamic compaction technique employed in the preliminary experimental phase was refined to represent a more realistic method. A novel method was thus designed to simulate the construction of a real-size prototype embankment, where a vibratory and static load was used to apply and control, respectively, the compaction effort. The hydraulic aspects of the embankment breach mechanism were also investigated. For the first time, scale series tests have been used to assess the Froude criterion using tilted and quasi-exact geometric scales under very low inflow within the scope of three-dimensional breach overtopping. Data measurements included a time-history of water surface levels and video footage captured from three locations: upstream, downstream and above the embankment models. The analysis for the spatial breach overtopping tests involved measurement of the breach outflow hydrograph and breach channel evolution at the upstream slope, using hydrologic routing and a developed photogrammetric technique using the video footage, respectively. An expression which estimates the breach outflow based on this apparent upstream control section was therefore derived. The relationship between the measured and estimated breach outflow was expressed in terms of breach discharge efficiency. The third phase of the experimental program was comprised of two-dimensional overtopping tests to investigate the erodibility of a steep slope in overtopped noncohesive embankment models. A novel experimental two-dimensional configuration used to measure the pore-water-pressures within the embankment model body was developed using micro and standard tensiometer-transducer-probe assemblies, designed, assembled and tested at the Geotechnical Engineering Laboratory. A transient flownet analysis was developed using ArcGIS and the time-history of the pore-water-pressure measurements. All flow parameters were computed using the free water surface and bed profiles captured using a photogrammetric technique and the developed hydrologic routing method. Using the one-dimensional Saint-Venant equations, an analytical expression for the bed shear stress was derived to take into account the effects of unsteady flow, boundary seepage and steep slopes. Using the measured erosion rates and the sediment continuity principle, the bed mobility relationship expressed by the Shields and transport parameters was revisited to account for the effects of unsteady and supercritical flow on a downstream steep slope in the presence of boundary seepage. This novel transient flownet approach will lead to the development of new sediment mobility relationships for breach flows, instead of the classical sediment transport-capacity formulations which are based on steady, subcritical and normal flow conditions.