At the Lampen site outside of Kalix, Sweden two embankments with heights 1,5m and 2m have been built to study and test the properties of sulfide soil that is located in the Gulf of Bothnia coastal areas. In this master thesis investigations have been done on what more could be done at the Lampen site today concerning new technics, measurements, observations and calculations etc. rather than building new embankments. Conclusions have been drawn from a total of 7 cases including Lampen what more could be done at the Lampen site. Verifications have also been done on the work made at the different cases. It was concluded that the work on all the different cases could be verified in some way against hand calculations or PLAXIS models beside the Murro test embankment site because this work had too little release data aterial given. Made verifications gave corresponding results to the described and measured ones in the real cases. Cases that have been looked at are: 􀀀 Murro test embankment (Karstunen et.al, 2005) 􀀀 Test embankment constructed to failure on soft marine clay in Malaysia (Brand, 1991) 􀀀 Test embankment on hydraulically placed PFA (Pulverized Fuel Ashes) in the United Kingdom (Cousens, et al., 2003) 􀀀 Trial Embankment on peat in Booneschans the Netherlands (Zwanenburg, et al., 2012) 􀀀 A case study on sulphide soil on road of E12 north link, Västerslätt, Umeå, Sweden (Törnqvist, 2013) 􀀀 Follow up and evaluation of settlements on the road 760 in Norrbotten, Sweden (Johansson, 2010) 􀀀 Test Embankments Lampen, Sweden (Andersson, 2012) From these cases it was concluded that more calculations in Plaxis 2D, Plaxis 3D and maybe Geosuite settlements software programs should be done at the Lampen site, both for long term and short term behavior and settlements as the only current model made is an Embacko V1.02 which is based on the work and results by Andersson (2012). Also verifications should be made by hand calculations on the models as this had not been done until today. Further disturbed samples should have been taken at the Lampen site as it have been done at the Murro site in Finland as this site is built on similar ground conditions with sulfide soil. Heavy equipment used at the site and as well the building of the embankments might have disturb or influenced the soil so the properties might have been changed. Also a couple of new measurement technics have been looked at for Lampen. The looked at technics are optics fibers, drones and ShapeAccelArray (SAA). ShapeAccelArray (SAA) devices could be installed at some different points on the site, down through the soil profile to give better readings on vibrations, accelerations, deformations and settlements. A drone could also be used during the snow free period to fly daily-predefined paths and make a 3D mapping of the geotechnical structures. And if the embankments would be built now again from the start it would be a good idea to install from the start a smart geotextile with polymer optical fibers (POF) totally covering the whole embankment size. This would give continues reading on deformations and displacements. But since the measurements and all other work at the Lampen site in the project went well and gave good results there is no need to do further changes.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2016. / Gold mining of the Witwatersrand Basin reefs has been responsible for the rise of Johannesburg as an economic centre of South Africa. While mining provided a base for business and infrastructure development for the region, it has also generated social and environmental problems for the country. Tailings storage facilities (TSFs), a common sighting around Johannesburg and across the entire basin, have been built to contain the processed waste following extraction of gold from the pyrite containing quartzite ore. When the fine grained waste is exposed to atmospheric conditions, oxidation of remnant sulphides occurs resulting in acidic, metal rich and sulphate rich plumes that enter the environment through surface and groundwater systems. This thesis sought to better understand the release, transport, dispersal and fate of metals emanating from TSFs and their remnant footprints on the Witwatersrand. These metals included aluminium, copper, chromium, iron, manganese, nickel and uranium and are known to be toxic to humans depending on their concentration and speciation. Traditionally, analytical methods have been employed in studies focussing on the characterisation of some of these processes in the region. While these studies have generally conducted quantitative assessment of the extent of pollution, little comprehensive interrogation and fingerprinting of the processes that are influential in determining the potential risk posed by metals has been done. This has largely been due to the shortcomings of analytical methods to determine these. To this end, this research has employed geochemical modelling to complement the traditional analytical methods. The approach to study the release of metals from TSFs involved assessment of the partitioning of metals within tailings and their potential release using batch and sequential extraction methods. Processes of metal release within the tailings were simulated through geochemical modelling (using the PHREEQC and Geochemist’s Workbench codes). The simulations were based on the percolation of rainwater through these layers and the changes in its chemistry along the path. The potential seepage of this plume along the path was then correlated to observed efflorescent mineral crusts that are temporary sinks for metals and are a common feature in the vicinity of the tailings and water bodies such as ponds and streams. The potential impact of the mineral crusts on the water chemistry of receiving water systems following their dissolution was assessed using forward geochemical modelling. The transport of the metals in groundwater was also studied. This involved simulations of the transition in chemistry of a plume from a TSF along an aquifer of known composition. This was based on a 1-D reactive transport model constructed using information from sequential extraction work on the aquifer rock (to identify the key minerals to consider) and site data (mainly flow rates) from previous studies. The processes occurring in the removal of metals from acid mine drainage (AMD) through a permanent sink in the form of a pump-and-treat plant in the Central Goldfield of the basin were simulated using PHREEQC. The findings from the research showed that two different plumes were produced from an abandoned TSF as a result of rainwater percolation, notably a plume produced from the dissolution of secondary salts formed in the oxidised layer and a sulphuric acid rich plume in the unoxidised layer. These differences were apparent in the geochemical composition of the mineral crusts collected on the walls of tailings dumps and from a pond into which the plumes were draining. On dissolution, mineral crusts were found to produce acidic solutions with crusts containing predominantly Fe producing pH values below 3. The simulated dissolution of various types of mineral crusts gave insight into the impact of minerals present in the smallest amount. This showed that the bulk mineralogy as determined by analytical techniques such as PXRD and remote sensing could not be used with confidence to deduce the impact of the mineral crusts on receiving water bodies. The characteristics of surface plumes released from tailings TSF were compared to other water systems in the area around Soweto, with complementary interpretation conducted using chemometric methods. From principal component analysis (PCA), surface water systems were found to form distinct groups largely influenced by mineral solubility, alkalinity and dissolved oxygen content. The 1-D reactive transport simulations involved acidic, metal and sulphate rich water ingressing the aquifer (below the TSF). Several scenarios were modelled including simulations with different dolomite contents; allowing for surface complexation and the presence of cation exchange surfaces. At a point 500 m from the water ingress in the dolomite rich aquifer, Fe and Mn were largely precipitated out (as confirmed by sequential extraction results on the aquifer rock) while the sulphate concentration was reduced by almost half. On the other hand, Ca concentrations were conservative largely because of continuous dissolution of dolomite and precipitation of gypsum along the flow path. The simulations of the high density sludge treatment plant involved forward modelling of the treatment process with the sludge responsible for the removal of trace metals from the incoming acid mine drainage. The model can be of use for cost and process optimisation at the facility. This research has had notable outputs in the form of publications; models on metal release, transport and attenuation; and models on pump-and-treat processes. These will form an important repository of information and for benchmarking any further studies related to AMD. / MT2016

O crescimento do número de Barragens de Enrocamento com Face de Concreto (BEFC) no Brasil e no mundo e os problemas relacionados com a movimentação da face motivaram o desenvolvimento deste estudo sobre o comportamento mecânico do enrocamento. Geralmente, as previsões dos movimentos diferenciais do maciço são feitas com base nas características de deformabilidade do material. Este trabalho apresenta um estudo de tensão-deformação de enrocamento baseado em análise numérica de uma seção de barragem de grande altura, com o objetivo de definir o estado e as trajetórias de tensões que influenciam os valores dos parâmetros de deformabilidade. Baseado nas condições de carregamento previstas para o maciço de enrocamento, foi desenvolvida a programação e as metodologias dos ensaios laboratoriais. A partir dos resultados destes ensaios foi possível estimar os parâmetros de deformabilidade do enrocamento a serem utilizados em estudos tensão-deformação. / The important growth in the number of Concrete Face Rockfill Dams (CFRD\'s) in Brazil and in the World, and the reported problems related to movements of the concrete slab, motivated the present study of mechanical behavior of the rockfill. In general, predictions of the differential movements within the rockfill mass are based on the deformation properties of the rockfill materials. This work presents a stress-strain study of the rockfill mass, based on a numerical analysis of a high dam cross section, aiming to define the stress state and stress paths that influence the deformability parameters. Based on the loading condition estimated for the rockfill mass, the program and the methodology for the laboratorial tests was set. From these test results it was possible to estimate the deformability parameters of the rockfill to be used in stress-strain analysis.

Earthen dams are often built into bedrock abutments and on bedrock foundations. Bedrock joints naturally occur in bedrock materials. These bedrock joints create voids for ground water to pass through. Historically earthen dams were sometimes built in direct contact with the bedrock joints, causing a contact point between the soil of the dam and the flowing water. It has been engineering practice to place grout into exposed bedrock joints for some time now. However, soil is not always cleaned out of bedrock joints before they are grouted, which leaves a weakness for water to push through. The purpose of this study is to understand the point at which water flowing through bedrock joints will erode soil from the earthen dam embankment. The information of how much soil is eroded away in an amount of time is also crucial to the scope of this study. The goals of this study were accomplished by building a physical model or apparatus of an earthen dam embankment on top of a simulated bedrock joint. Different soil types were tested in the apparatus to start a database of information about erosion rates of the soil along the bedrock joint and embankment interface. These results will be used to start a database for organizations that assign probabilities of dam failures. The purpose of the study is not to indicate when dams will fail, but to help with assigning probabilities of the likelihood of a serious problem being caused from this type of mechanism presented in this study.

Muskeg or peat deposits cover large areas in northern Manitoba. Test sections of a newly constructed highway on peat were instrumented to investigate their performance and to develop more economical means of construction method. Test Section ‘A’ was constructed with geotextile base layer while Section ‘B’ was with geotextile and corduroys (timber logs). The test sections were constructed during winter for ease in mobilizing construction equipment at the site when the ground was frozen and were instrumented to observe its behaviour and performance. Settlements were measured using monitoring plates and pins. Ground temperatures were measured using thermistors. Porewater pressures were measured using vibrating wire piezometers. Peat in the study area has an average thickness of 4m, with the upper layer classified as fibrous and the lower layer as amorphous with strong to complete decomposition. Standard laboratory tests were conducted on bored samples from the site. Hydraulic conductivity tests were carried out at different vertical pressures to determine its permeability. Thermal conductivity was determined at frozen and unfrozen state of peat. Conventional incremental oedometer tests were conducted to determine the compressibility parameters and secondary compression indices of the peat layers. Constant-rate-of-strain (CRS) tests were also performed to supplement the results obtained from the conventional method. Isotropically-Consolidated Undrained (CIŪ) triaxial tests were carried out to determine the shear strength of peat. A commercially-available computer program was used in the numerical modelling to simulate the field performance of the instrumented sections. The results from numerical modelling were reasonably close to the measured values in the field. Laboratory-scale physical modelling was undertaken to understand further the operating mechanisms involved in the performance of the two test sections under a more controlled environment. Artificial transparent clay that has similar deformation properties with most of the natural clays and peats was used as foundation material. It allows determination of spatial deformations beneath the embankment using Particle Image Velocimetry (PIV) technique. The load-settlement behaviour in the field was also reasonably simulated in the laboratory-scaled physical model. Deformation patterns from PIV indicate that embankment with geotextile layer and corduroy has smaller settlements and lateral movements in the foundation compared to that of the embankment with only geotextile layer.

published_or_final_version / Applied Geosciences / Master / Master of Science

O presente trabalho detalha o conceito de Projeto Interativo aplicado à obra de ampliação dos Molhes da Barra do Rio Grande-RS, uma das maiores obras de infraestrutura portuária do Brasil, a qual se desenvolve em substrato argiloso de baixa capacidade de suporte e elevada compressibilidade, com espessura média de 10m. A obra de ampliação dos molhes e sua estratigrafia são detalhados após a revisão de critérios de alerta aplicados à aterros sobre solos moles. Posteriormente com o intuito de aferir modelos, fez-se uma análise da sensibilidade dos parâmetros de projeto, através da aplicação dos conceitos de segurança segundo o Método dos Volumes Deslocados, a qual definiu que a relação de volumes deslocados (dVv/dVh - razão de volume vertical deslocado, dVv, por volume horizontal deslocado, dVh) é suscetível às condições de drenagem, aos parâmetros de resistência e compressibilidade do solo de fundação, da geometria da área carregada e dos locais onde as leituras são realizadas. A dependência das leituras a este conjunto de fatores reforça a necessidade de análises numéricas específicas para definição de níveis de alerta. A análise paramétrica observou também que a aferição de parâmetros deve ser feita distintamente entre parâmetros de resistência e compressibilidade. De posse destas observações foram aferidos os parâmetros de projeto. Sequencialmente fez-se a reavaliação das seções de simulação numérica através de uma retroanálise quando do alteamento dos molhes à cota +2m. Observou-se que as simulações conseguiram capturar o comportamento em campo, em termos de deslocamentos horizontais e verticais, distorções e poro pressão. Este procedimento foi repetido até a fase de fechamento dos molhes, retroanalisando-se etapas anteriores de construção para refinar a estimativa das etapas subsequentes, garantindo-se as condições de segurança da obra. Com base neste estudo apresenta-se uma discussão quanto à postulação de critérios de segurança em obras geotécnicas, observando que estes devem ser abrangentes, de acordo com as características da obra, definindo deformações máximas e controle de taxas de deformação e, em particular, a taxa de distorção que cresce linearmente próximo à ruptura e diminui quando do aumento da estabilidade durante o período de adensamento. / The concept of Interactive Design applied to a marine breakwater in Rio Grande-RS, southern Brazil, is described in the present paper. Besides a literature review concerning constructions control methods applied in soft soil embankments, the characteristics of the site and construction work are presented and, the stratigraphy is detailed, which is characterized by a soft foundation substrate of low capacity and high compressibility, with a thickness about 10m. Based on the need to postulate security levels in geotechnical projects, according the soft layer that support the current construction, the first steep was to perform a parametric evaluation of the breakwater using the Displaced Volume Method, a field stability control for embankments on soft soil. This parametric analyses shows that dVv/dVh (ratio of vertical volume displaced, dVv, per horizontal volume displaced, dVh) is a function of drainage conditions, strength and compressibility parameters, loaded area geometry, and location of measured points. The analysis is shown to be particularly sensitive to friction angle and compressibility .Given the sensitivity of the security analysis to several different parameters and geometrical conditions, it has been stressed that specific numerical analysis should be performed for every geotechnical problem. Using these observations, soil foundation parameters, obtained in the breakwater region, were checked, and recalibrated. After that, some back analysis to verify the models was made in all instrumentation sections. It was observed that the simulations were able to capture the measured behavior of horizontal and vertical displacements, distortions, and pore pressures. The analysis was repeated for different construction phases, so that a back-analysis of a previous stage could refine the predictions of the following stage. Finally, a field control is presented according to acceptable ranges of displacements, distortion and specially distortions rates, which increases linearly near the failure and decreases when increasing stability due to consolidation effects.

O presente trabalho detalha o conceito de Projeto Interativo aplicado à obra de ampliação dos Molhes da Barra do Rio Grande-RS, uma das maiores obras de infraestrutura portuária do Brasil, a qual se desenvolve em substrato argiloso de baixa capacidade de suporte e elevada compressibilidade, com espessura média de 10m. A obra de ampliação dos molhes e sua estratigrafia são detalhados após a revisão de critérios de alerta aplicados à aterros sobre solos moles. Posteriormente com o intuito de aferir modelos, fez-se uma análise da sensibilidade dos parâmetros de projeto, através da aplicação dos conceitos de segurança segundo o Método dos Volumes Deslocados, a qual definiu que a relação de volumes deslocados (dVv/dVh - razão de volume vertical deslocado, dVv, por volume horizontal deslocado, dVh) é suscetível às condições de drenagem, aos parâmetros de resistência e compressibilidade do solo de fundação, da geometria da área carregada e dos locais onde as leituras são realizadas. A dependência das leituras a este conjunto de fatores reforça a necessidade de análises numéricas específicas para definição de níveis de alerta. A análise paramétrica observou também que a aferição de parâmetros deve ser feita distintamente entre parâmetros de resistência e compressibilidade. De posse destas observações foram aferidos os parâmetros de projeto. Sequencialmente fez-se a reavaliação das seções de simulação numérica através de uma retroanálise quando do alteamento dos molhes à cota +2m. Observou-se que as simulações conseguiram capturar o comportamento em campo, em termos de deslocamentos horizontais e verticais, distorções e poro pressão. Este procedimento foi repetido até a fase de fechamento dos molhes, retroanalisando-se etapas anteriores de construção para refinar a estimativa das etapas subsequentes, garantindo-se as condições de segurança da obra. Com base neste estudo apresenta-se uma discussão quanto à postulação de critérios de segurança em obras geotécnicas, observando que estes devem ser abrangentes, de acordo com as características da obra, definindo deformações máximas e controle de taxas de deformação e, em particular, a taxa de distorção que cresce linearmente próximo à ruptura e diminui quando do aumento da estabilidade durante o período de adensamento. / The concept of Interactive Design applied to a marine breakwater in Rio Grande-RS, southern Brazil, is described in the present paper. Besides a literature review concerning constructions control methods applied in soft soil embankments, the characteristics of the site and construction work are presented and, the stratigraphy is detailed, which is characterized by a soft foundation substrate of low capacity and high compressibility, with a thickness about 10m. Based on the need to postulate security levels in geotechnical projects, according the soft layer that support the current construction, the first steep was to perform a parametric evaluation of the breakwater using the Displaced Volume Method, a field stability control for embankments on soft soil. This parametric analyses shows that dVv/dVh (ratio of vertical volume displaced, dVv, per horizontal volume displaced, dVh) is a function of drainage conditions, strength and compressibility parameters, loaded area geometry, and location of measured points. The analysis is shown to be particularly sensitive to friction angle and compressibility .Given the sensitivity of the security analysis to several different parameters and geometrical conditions, it has been stressed that specific numerical analysis should be performed for every geotechnical problem. Using these observations, soil foundation parameters, obtained in the breakwater region, were checked, and recalibrated. After that, some back analysis to verify the models was made in all instrumentation sections. It was observed that the simulations were able to capture the measured behavior of horizontal and vertical displacements, distortions, and pore pressures. The analysis was repeated for different construction phases, so that a back-analysis of a previous stage could refine the predictions of the following stage. Finally, a field control is presented according to acceptable ranges of displacements, distortion and specially distortions rates, which increases linearly near the failure and decreases when increasing stability due to consolidation effects.

O crescimento do número de Barragens de Enrocamento com Face de Concreto (BEFC) no Brasil e no mundo e os problemas relacionados com a movimentação da face motivaram o desenvolvimento deste estudo sobre o comportamento mecânico do enrocamento. Geralmente, as previsões dos movimentos diferenciais do maciço são feitas com base nas características de deformabilidade do material. Este trabalho apresenta um estudo de tensão-deformação de enrocamento baseado em análise numérica de uma seção de barragem de grande altura, com o objetivo de definir o estado e as trajetórias de tensões que influenciam os valores dos parâmetros de deformabilidade. Baseado nas condições de carregamento previstas para o maciço de enrocamento, foi desenvolvida a programação e as metodologias dos ensaios laboratoriais. A partir dos resultados destes ensaios foi possível estimar os parâmetros de deformabilidade do enrocamento a serem utilizados em estudos tensão-deformação. / The important growth in the number of Concrete Face Rockfill Dams (CFRD\'s) in Brazil and in the World, and the reported problems related to movements of the concrete slab, motivated the present study of mechanical behavior of the rockfill. In general, predictions of the differential movements within the rockfill mass are based on the deformation properties of the rockfill materials. This work presents a stress-strain study of the rockfill mass, based on a numerical analysis of a high dam cross section, aiming to define the stress state and stress paths that influence the deformability parameters. Based on the loading condition estimated for the rockfill mass, the program and the methodology for the laboratorial tests was set. From these test results it was possible to estimate the deformability parameters of the rockfill to be used in stress-strain analysis.

O presente trabalho detalha o conceito de Projeto Interativo aplicado à obra de ampliação dos Molhes da Barra do Rio Grande-RS, uma das maiores obras de infraestrutura portuária do Brasil, a qual se desenvolve em substrato argiloso de baixa capacidade de suporte e elevada compressibilidade, com espessura média de 10m. A obra de ampliação dos molhes e sua estratigrafia são detalhados após a revisão de critérios de alerta aplicados à aterros sobre solos moles. Posteriormente com o intuito de aferir modelos, fez-se uma análise da sensibilidade dos parâmetros de projeto, através da aplicação dos conceitos de segurança segundo o Método dos Volumes Deslocados, a qual definiu que a relação de volumes deslocados (dVv/dVh - razão de volume vertical deslocado, dVv, por volume horizontal deslocado, dVh) é suscetível às condições de drenagem, aos parâmetros de resistência e compressibilidade do solo de fundação, da geometria da área carregada e dos locais onde as leituras são realizadas. A dependência das leituras a este conjunto de fatores reforça a necessidade de análises numéricas específicas para definição de níveis de alerta. A análise paramétrica observou também que a aferição de parâmetros deve ser feita distintamente entre parâmetros de resistência e compressibilidade. De posse destas observações foram aferidos os parâmetros de projeto. Sequencialmente fez-se a reavaliação das seções de simulação numérica através de uma retroanálise quando do alteamento dos molhes à cota +2m. Observou-se que as simulações conseguiram capturar o comportamento em campo, em termos de deslocamentos horizontais e verticais, distorções e poro pressão. Este procedimento foi repetido até a fase de fechamento dos molhes, retroanalisando-se etapas anteriores de construção para refinar a estimativa das etapas subsequentes, garantindo-se as condições de segurança da obra. Com base neste estudo apresenta-se uma discussão quanto à postulação de critérios de segurança em obras geotécnicas, observando que estes devem ser abrangentes, de acordo com as características da obra, definindo deformações máximas e controle de taxas de deformação e, em particular, a taxa de distorção que cresce linearmente próximo à ruptura e diminui quando do aumento da estabilidade durante o período de adensamento. / The concept of Interactive Design applied to a marine breakwater in Rio Grande-RS, southern Brazil, is described in the present paper. Besides a literature review concerning constructions control methods applied in soft soil embankments, the characteristics of the site and construction work are presented and, the stratigraphy is detailed, which is characterized by a soft foundation substrate of low capacity and high compressibility, with a thickness about 10m. Based on the need to postulate security levels in geotechnical projects, according the soft layer that support the current construction, the first steep was to perform a parametric evaluation of the breakwater using the Displaced Volume Method, a field stability control for embankments on soft soil. This parametric analyses shows that dVv/dVh (ratio of vertical volume displaced, dVv, per horizontal volume displaced, dVh) is a function of drainage conditions, strength and compressibility parameters, loaded area geometry, and location of measured points. The analysis is shown to be particularly sensitive to friction angle and compressibility .Given the sensitivity of the security analysis to several different parameters and geometrical conditions, it has been stressed that specific numerical analysis should be performed for every geotechnical problem. Using these observations, soil foundation parameters, obtained in the breakwater region, were checked, and recalibrated. After that, some back analysis to verify the models was made in all instrumentation sections. It was observed that the simulations were able to capture the measured behavior of horizontal and vertical displacements, distortions, and pore pressures. The analysis was repeated for different construction phases, so that a back-analysis of a previous stage could refine the predictions of the following stage. Finally, a field control is presented according to acceptable ranges of displacements, distortion and specially distortions rates, which increases linearly near the failure and decreases when increasing stability due to consolidation effects.