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Use of geosynthetics to close a contaminated area in a metallurgical industry in the state of bahia
No full textThe study for closure and monitored natural attenuation/stabilization of industrial waste deposits plays a fundamental role in the process of groundwater quality management, providing information for understanding the contaminants evolution and enabling decision-making, with the purpose of isolating waste, contaminant concentrations, toxicity and mass and/or volume reduction to levels adequate to protect human health and the environment, within a reasonable period of time. The aim of this study was to propose an environmental remediation solution for a contaminated material disposal area using the case study of a metallurgical industry located in Bahia, Brazil. To this purpose, four conditions were provided for compliance: i) control of dust, odor and erosion, ii) control of contaminant release, iii) chemical stabilization of waste and iv) soil recovery. Based on the results obtained in environmental investigation studies and information from the area, the best solution in an attempt to naturally stabilize the area would be the use of geosynthetics as a physical barrier between the contaminated material disposed in the area and the rainwater. In this way, infiltration of rainwater into the landfill and the migration of percolated liquid with risk of contamination to the soil, groundwater table and surface water bodies is avoided. It is still possible to monitor the effectiveness of the proposed solution with the installation of instrumentation such as water level indicators and piezometers
Estimation of Pore Pressure for Unsaturated-Saturated Bentonite Sand Mixture
Get PDFTo investigate thermal hydration mechanical chemical couple phenomena is an important issue of the high-level radioactive waste disposal and a key indicator of artificial barrier system. Major objectives of the thermal and mechanical site characterization include the status of the environmental. Several research reports are aimed at the barrier layers for heating from radioactive waste disposal. This study appears the occurrence of the pore pressure under heat conditions for bentonite and bentonite-sand mixture material, which are completely undrained condition and unexhausted condition. It is considered that mechanics of pore pressure in macro-micro void structure due to heating-cooling repetition. A thermal chamber is used in heating method, which have high specification with accurate controlling sensitivity. The maximum temperature is 80 degrees Celsius temperatures. The prepared specimens are unsaturated specimens and saturated specimens, and silica sand are mixture into three different bentonites that various dry densities are required. Two different solutions are prepared for saturated specimen, which are distilled water and salinity water with concentration of 3.5 %. The specimens are placed into a thermostat oven, and heating application is applied isotropic conductivity. The obtained results are significant as followings; The measured pore pressures are obviously with increment of temperature, and the sand mixture ratio is small influence factor. Also, large por fluid pressures are produced for saturated condition that indication of small pore fluid pressure is verified for unsaturated specimen comparison with saturated specimen
Multi-Sensor Core Logging of Marine Sediments for Continuous Thermal Conductivity Profiles
Get PDFThermal conductivity of shallow
In situ and laboratory results of a bentonite-based block/pellet seal during saturation
Get PDFThe in situ Engineered Barrier (EB) experiment aimed at understanding the hydromechanical behaviour of sealing materials for high-level radioactive wastes as a combination of compacted blocks and high-density pellets made of Febex bentonite. The experimental program focused on the wetting process of a heterogeneous dual-component sample consisting of pellets and blocks with technological gaps. The homogenisation tendency was investigated by determining the final (local) dry densities and pore size distributions in both zones from post-mortem analyses. Global initial dry densities between 1.36–1.44 Mg/m3 were considered for the heterogeneous mixture, wetted at constant volume and constant vertical stress (oedometer conditions). The initially high-density zone of blocks with technological gaps expanded during hydration, reaching a lower dry density at saturation than the pellets’ zone. The initially low-density pellets’ zone with a high volume of inter-pellet pores underwent compression and reached a final high dry density on saturation. The experimental results were compared with the distribution of dry density at the in situ EB experiment after dismantling, and a good agreement between the laboratory and the in situ measurements was observed
Experience of in situ geotechnical tests and their interpretation in organic soils and peat
Get PDFThis paper reviews the use of piezocone (CPTU) testing to characterise and identify peats and organic soils. Examples of data for peat sites from several countries are given, including some experience of the use of T-bar and piezoball penetrometers in peat. These “full flow” devices show smoother resistance profiles than the equivalent from the CPTU and are perhaps representative of the peat mass with a reduced fibre effect. In CPTU tests, organic soils and peat are often characterised by low corrected cone resistance (qt) and high friction ratio (Rf). CPTU penetration in peat is often drained with data showing low pore water pressure coefficient (Bq) values. Rf broadly decreases with increasing degree of decomposition of the peat. However care needs to be taken in using Rf values in peat given the characteristically very low sleeve friction values (fs) encountered. It would seem that it is not always easy to distinguish between peat and underlying soft soils using CPTU alone. There may be some promise in inclusion of CPTU “add on” sensors particularly a seismic element to yield shear wave velocity (Vs). However there is some uncertainty in measuring Vs in peat both offshore and onshore so care is needed in this regard. Recently developed Soil Behaviour Type (SBT) charts from the Netherlands have also been trialled on several sites. This new formulation shows promise and warrants further stud
Can Seabed Spatial Uncertainty Be Quantified Using Advanced Statistical Approaches?
Get PDFKnowledge of seabed properties away from investigated locations is often required, for example, when geotechnical surveys are sparse or when the field layout changes between investigation and construction phases. In such cases, design lines that appropriately incorporate the uncertainty of the seabed properties must be defined to ensure reliable (yet not overly costly) design. This paper explores how two different approaches, traditional engineering judgement and advanced statistical methods, fare at quantifying the uncertainty of a real offshore site. This is achieved by ‘hiding’ different data and ‘scoring’ the predictive performance of the methods against a range of criteria. The work reveals that complex geological sites are significantly more challenging to represent than the stationary random fields often examined in research and suggests that more advanced approaches incorporating broader data sets are required to reduce uncertainty
Geological and geotechnical study of a construction site in Porto Romano area-Albania
Get PDFPorto Romano port complex new facilities are part of the expansion plans of Durres port and its modernisation. However, the relocation site presented many significant spatial and geotechnical challenges to be considered and mitigated. Soil conditions and the country’s high seismic activity meant the project required extensive feasibility and technical studies to find a safe and sustainable approach. For a detailed geological and geotechnical investigation of the area, various geotechnical, geophysical tests were carried out such as: borings, SPT test, CPTU test, Seismic refraction, MASW, Downhole and HVSR allowing to obtain the fundamental resonance frequency of the ground. Field recordings per each layer were than compared and calibrated to the results and tests performed in the laboratory. The construction site displayed a variety of soils from soft to firm silty Clays, to loose to medium dense silty Sands and layers with high organic content. During execution of SPT tests, sandy layers gave more satisfactory results, meanwhile, for silty CLAY layers, the results of CPTU testing were considered in analysis. This detailed soil investigation and characterization served to properly design the new port facilities, identify, and protect from the liquefaction phenomena at this specific site
Està el teixit industrial català preparat per a l’arribada de nous fabricants de vehicles? El cas de Chery.
No full textEl 12 d’abril de 2024 Chery va signar un acord amb l’empresa catalana Ebro-EV Motors per a poder assemblar al D-Hub l’Omoda 5, un dels principals models del fabricant xinès. Les previsions més optimistes indiquen que aquest podria ser el primer de més models que podrien acabar assemblant-se a l’antiga fàbrica de Nissan a la Zona Franca. L’objectiu de l’empresa asiàtica és fabricar 150.000 vehicles cap el 2029.
De manera inicial, la producció a la planta de Zona Franca es limitarà a l’assemblatge de grans parts del vehicle que s’importaran de la Xina semidesmuntats, el procés anomenad DKD (Disassembled Knocked-Down). Aquest procés sol implicar la fabricació complerta del vehicle al país d’origen i el seu desmuntatge parcial per a ser transportat i rearmat a la planta de destí per a ser venut al mercat objectiu. Aquesta estratègia de producció pot esdevenir la primera fase cap a processos a on cada cop es vagin fabricant més parts a la planta de destí (MKD: Medium Knocked-Down; SKD: Semi Knocked-Down) fins a arribar a la fase CKD (Completely Knocked-Down), en la que, si bé la major part de components ja es fabriquen a la planta de destí, molts petits components continuen essent importants.
L’objectiu de la recerca és analitzar si el teixit industrial català de l’automoció estaria preparat per assumir el repte d’aprovisionar a un nou OEM, en aquest cas Chery, si aquesta empresa decideix passar del model DKD actual a un model CKD. Es vol valorar fins a quin punt Chery podria trobar a Catalunya una oferta de components amb prou massa crítica com per plantejar-se aquest canvi productiu.
Per a la recerca s’utlitzarà la base de dades internacional anomenada “Marklines”, que conté informació detallada de més de 70.000 proveïdors del sector de l’automoció de tot món. Am certa aproximació, aquesta base de dades por indicar quins proveïdors ha estat utilitzant Chery en els darrers anys i per a quins components dels seus vehicles. A la vegada, també pot indicar en cada país quines empreses operen en la producció cadascun d’aquests components. Generant i creuant aquestes bases de dades es podrà analitzar amb certa aproximació quins components dels que necessita Chery ja es produeixen a Catalunya i quins els haurien d’importar de fora del Principat.
Amb aquest estudi s’espera contribuir al coneixement del teixit productiu català del sector de l’automoció i oferir una informació qualitativa sobre la capacitat de la indústria catalana a l’hora de traccionar una oportunitat potencial com és l’arribada de Chery a Catalunya o de qualsevol altre OEM que s’hi vulgui establir per a produir models de combustió, baixes o zero emissions
La descarbonització industrial europea i la paradoxa dels ‘early adopters’
No full textL’article pretén acreditar com la Unió Europea es troba en una posició de lideratge pel que fa a la descarbonització de les economies que la conformen, particularment en relació a la manufactura industrial. Aquest procés es deu fonamentalment a la substitució de fonts energètiques derivades dels combustibles fòssils per d’altres d’alternatives, no només de forma espontània sinó també guiada per la política fiscal; per exemple, a través de l’existència del programa EU-ETS (Emissions Trading System) pel qual molts sectors industrials han de pagar una taxa per cada tona de CO2 que emeten. El resultat de combinar una fiscalitat pigouviana per fomentar aquest procés de descarbonització juntament amb la realitat que moltes de les fonts energètiques o tecnologies substitutives tenen un cost primari més elevat que les opcions menys sostenibles deriva en una degradació de l’estructura de costos per a una diversitat de sectors industrials europeus. Aquest fenomen es veu accentuat pel caràcter embrionari de moltes d’aquestes alternatives tecnològiques verdes, que previsiblement disminuiran el seu cost durant les properes dècades. Es pretén posar de manifest el risc de que el lideratge temporal en aquesta transició acabi implicant per a Europa assumir uns costos industrials poc competitius en el context internacional, mentre que altres geografies poden adoptar aquestes solucions un cop ja se n’hagi validat la seva viabilitat tecnològica i iniciat la corba decreixent de costos. Es vol avaluar de quina manera aquest escenari pot derivar en una nova onada de deslocalització industrial que resulti en l’efecte contrari: unes majors emissions de CO2 incrustades dins dels productes dels quals Europa seria netament importadora. Es pretenen posar de manifest alguns instruments de fiscalitat, com el mecanisme de compensació a frontera, orientats a mitigar aquests efectes, així com analitzar-ne els pros i contres
Installation of Load Cells in Ground Anchors
Get PDFLoad cells are used to measure tension (kN, tonne-force) in ground anchors and tendons in pre- or post-tensioned structures. Before installing and commissioning, it is strictly necessary to know the characteristics of the anchors to control as well as the installation and service scenery. Although it may look a simple assignment, there are several issues before supplying and installing a load cell: geometry of the anchor head, measurement range, expected precision, type of output signal and data transmission, temperature variations in the structure, and foreseen service life. The sort of tensioning jack and load steps are additional, unavoidable points to consider. By installing a load cell on a tieback, this is transformed into a measurement element, helping to understand the performance of the anchor as well as that of the surrounding area, medium- and long-term. To ensure load cells’ values are correct, we must take extra care with installation. Otherwise, the outcome will be flawed, and it will lead to erroneous conclusions and actions, with the subsequent increase in risk and money loss. In this paper, we share our experience regarding design, installation, and follow-up of load cells as elements to monitor the behaviour of anchored and post-tensioned structures and their area of influenc