Administraçao

A generic framework for the updating geomechanical parameters is presented. It is based on Bayesian probabilities, and considers several levels of uncertainty. It allows one to properly update the probability distribution function of a given parameter when new data are available. This framework is applied to the case of deformability modulus updating in a large underground structure. Two different approaches were tested in terms of initial knowledge about the parameter, namely no knowledge, and a prior distribution of the parameter based on geological/geotechnical data and application of analytical solutions based on the empirical classification systems. The updating was carried out using the framework together with the results of high quality in situ tests. The Bayesian framework was shown to be a mathematically valid way to deal with the problem of the geomechanical parameter updating and of uncertainty reduction related to the parameter's real value.

In this paper a KBS computational system, designated by GEOPAT, for the calculation of geomechanical parameters for modelling underground structures in rock and soil formations is presented. To congregate the specialists' knowledge in rock and soil domains, and in particular in the tunnel engineering, causal nets have been established for decision support. GEOPAT determines the parameters for rock and soil formations, as well as heterogeneous rock formations. The developed GEOPAT system was applied to a large underground station in urban environment, excavated in granite formations, in order to obtain the deformability and strength parameters of the surrounding rock masses. Numerical models were developed considering either the obtained geomechanical parameters using artificial intelligence techniques or the parameters used in design. The numerical results obtained with the two sets of parameters are compared, as well as with the monitoring results. Some conclusions are drawn.

The collection of geomechanical information is a complex and dynamic process. As new information is available, the geotechnical model can be updated. However, this is not a straightforward process since the information sources may have different characteristics and reliability levels. This is a process based on judgment and experience. It lacks a systematic and mathematically valid process to deal with this problem and use new information to update the model parameters in order to reduce uncertainties. In this paper, it is intended to provide a contribution on this subject. A generic Bayesian framework for the updating of geomechanical parameters is presented. Emphasis is given to the theoretical aspects of uncertainty and to the Bayesian formulation. This framework is applied to the case of the deformability modulus updating in an underground structure. The prior distribution of the parameter was obtained through de application of analytical solutions based on the empirical classification systems. This distribution was then updated using the framework together with the results of a high quality in situ test. The Bayesian framework showed to be a mathematically valid way to deal with the problem of the geomechanical parameters updating and mostly in the uncertainty reduction related to the parameter real value.

RESUMO: O presente trabalho descreve sistemas computacionais que estão em fase de desenvolvimento e aperfeiçoamento e que servirão para a análise de risco dos túneis da rede de comboios de alta velocidade a ser construída em Portugal. Um dos sistemas, designado GEOPAT, serve para prever parâmetros geomecânicos para a modelação de obras subterrâneas. Neste trabalho serão apresentadas duas aplicações que já foram efectuadas nesta fase de desenvolvimento do sistema a duas importantes obras subterrâneas construídas no Norte de Portugal. O outro sistema, designado MATUF, está vocacionado para o apoio a operações de manutenção e inspecção dos túneis.

Due to the inherent geological complexity and characterization difficulties in rock formations, the evaluation of geomechanical parameters is very complex, mostly in the initial project stages and in small-scale geotechnical works, where information is scarce for the definition of an accurate geotechnical model. However, in large geotechnical projects, a great amount of data are produced and used to establish near-homogeneous geotechnical zones. If properly analyzed, these data can provide valuable information that can be used in situations where knowledge of the rock mass is limited. Yet, this implies the organization of geotechnical data in formats for proper analysis using advanced tools which is not normally done. Data-mining techniques have been successfully used in many fields but scarcely in geotechnics. They seem to be adequate as an advanced technique for analyzing large and complex databases that can be built with geotechnical information within the framework of an overall process of knowledge discovery in databases ͑KDD͒. In this work, a first approach of a KDD process applied in the context of rock mechanics is presented. The main goal was to find new models to evaluate strength and deformability parameters. In this process, a large database of geotechnical data was assembled concerning an important underground structure built in a predominantly granite rock formation. These innovative methodologies and tools were used to analyze and extract new and useful knowledge. The procedure allowed developing new, simple, and reliable models to predict geomechanical parameters, namely friction angle, cohesion, and deformability modulus using different sets of input data that can be used in different situations of information availability.

In geotechnical engineering, and in the particular case of underground works, a great number of uncertainties arise due to the lack of knowledge of the involved formations and their variability. Geomechanical parameters are one of the main issues in the underground works design. In the initial stages, the available information about the rock masses characteristics is scarce. As the project advances to other stages more and more information from different sources becomes available and can be used for updating the geomechanical model. Bayesian methodologies use probability as the main tool to deal with uncertainty and manage to reduce it using new data via the Bayes theorem. In this work, a part of a developed Bayesian framework to the updating of the deformability modulus (E) in an underground structure is presented. Assuming E as a random variable, data from LFJ tests is used to obtain a posterior and less uncertain distribution of E. This approach led to good results and considerable uncertainty reduction and increased reliability. The developed Bayesian framework constitutes a rational and structured way of dealing with data with different sources and uncertainty levels.

The evaluation of geomechanical parameters for rock masses is one of the issues with largest uncertainty degree. This is mostly true in the preliminary stages of design and in small works where geotechnical information is normally scarce. In these cases, geotechnical data from past projects could help in the definition of design values for the parameters. Data Mining techniques have been successfully used in many fields. They are advanced techniques which allow to analyse large and complex databases like the ones it would be possible to build with geotechnical information. In this context, it was intended to gather a large database of geotechnical data and use these innovative tools to analyse and induce new and useful knowledge. The main goal was to develop new and reliable models to predict geomechanical parameters values mainly when only limited data is available.Entwicklung neuer Modelle für die geomechanische Charakterisierung unter Anwendung der “Data Mining”-TechnikDie Evaluierung von geomechanischen Gebirgsparametern gehört zu den Fragestellungen, die mit den größten Unsicherheiten behaftet sind. Dies trifft insbesondere für frühe Planungsphasen zu, in denen geotechnische Informationen oft nur sehr eingeschränkt vorliegen. Für Planungsarbeiten in diesem Stadium könnten geotechnische Daten von bereits durchgeführten Projekten bei der Festlegung der Entwurfswerte äußerst hilfreich sein. “Data Mining”-Techniken wurden in vielen Projekten bereits mit Erfolg angewendet. Grundsätzlich ist beabsichtigt, eine große Datenbank mit geotechnischen Informationen zu befüllen und diese in der Folge zu analysieren und daraus neue Erkenntnisse zu gewinnen. Ziel ist, unter Zuhilfenahme der Datenbank bereits in frühen Planungsphasen – auch wenn aus dem Projekt selbst nur beschränkte geotechnische Informationen zur Verfügung stehen – zuverlässige geomechanische Modelle zu entwickeln.

RESUMO: No Norte de Portugal está a ser construído um grande complexo hidroeléctrico subterrâneo como reforço de potência de um sistema hidroeléctrico existente desde 1951. Este novo complexo inclui um circuito hidráulico com 4,4 km de comprimento e duas cavernas para o conjunto da central. Os parâmetros geomecânicos das formações graníticas interessadas foram obtidos através de um programa chamado GEOPAT, que utiliza técnicas de inteligência artificial. Permite calcular parâmetros geomecânicos para a modelação do comportamento estrutural das obras subterrâneas. Foram desenvolvidos modelos numéricos para a análise do comportamento das cavernas do complexo da central utilizando parâmetros obtidos pelo GEOPAT. Os valores calculados a partir dos modelos numéricos foram comparados com os correspondentes valores observados apresentando na globalidade uma boa concordância. • Circuito hidráulico com um túnel em carga com 2,8 km de comprimento, 7,3 m de diâmetro e 14,8% de inclinação e um túnel de restituição com 1,4 km de comprimento, 6,3 m de diâmetro e 2,1% de inclinação. • Duas cavernas localizadas a 350 m de profundidade, para a central e para os transformadores, com forma rectangular em planta com 19,0x60,5 m 2 e 14,1x39,8 m 2 , respectivamente, ligadas por duas galerias.

Textile dyes are an important class of synthetic organic compounds and are therefore common industrial pollutants. They are produced in large scale and may enter the environment during production or later on during fibre dyeing. Due to the stability of modern dyes, conventional biological (activated sludge) treatment methods for industrial wastewater are ineffective, resulting in an intensively coloured discharge from the treatment facilities. Thus, there is a need for developing treatment methods that are more effective in eliminating dyes from waste stream at its source.

The Luiz Bandeira Bridge is located along the Portuguese national road EN333-3, breaching the valley of the Vouga River, just northeast of the small village Sejães, in the district of Oliveira de Frades. It is considered to be the oldest concrete bridge in use in Portugal, and one of the oldest in Europe. Since this bridge is at risk of disappearing due to a construction of a dam, the Department of Civil Engineering of the University of Minho decided to launch a comprehensive study of Luiz Bandeira Bridge, in an attempt to preserve the memory of the past cataloguing the heritage for future reference. These studies include historical, geometrical and damage surveys, the physical and chemical characterization of existing structural materials, the assessment of the reinforcement detailing, dynamic characterization by determining the main frequencies and vibration modes and safety level. This work presents a comprehensive overview of the most important results of these studies.

Foram realizados ensaios SPT, DPH, DPL e CPT nos solos graníticos em vários locais urbanos da Região Norte de Portugal, essencialmente do Porto, Braga e Guimarães. Obtiveram-se correlações entre resultados dos ensaios SPT-DPH; CPT-DPL; CPT-DPH e DPH-DPL, que são apresentadas. Para a correlação SPT-DPH os resultados do penetrómetro usado foram convertidos nos do penetrómetro indicado no Eurocódigo 7 (parte 3) com vista a uma normalização. Os resultados do SPT foram afectados do factor profundidade segundo a regra prevista no mesmo Eurocódigo (EC7).

O século V a.C. foi um forte período de idéias e soluções na Grécia.A democracia ateniense tinha como base o princípio de igualdade de todos perante a lei. Cidadãos atenienses participavam da Assembléia (uma reunião periódica), debatendo qualquer assunto que fosse de decisão do governo. Influenciadas pelas idéias de democracia, estratégia, igualdade de todos perante a lei, ética na administração pública, planejamento urbano, os gregos construíram sua história. E dessa forma, contribuíram para a civilização. Pode-se citar alguns itens que os gregos nos deixaram para facilitar em nossa sociedade atual, entre elas: Administração participativa e direta na democracia. Buscavam sempre mais conhecimento por investigação. Utilizavam da lógica para realização de fins. Os administradores da pólis ficavam responsáveis pela felicidade das cidades. Preocupavam-se com o bom e o belo. Platão, grande filósofo, sugeriu que somente os mais esclarecidos eram capazes de governar. Dizia também que as políticas eram responsáveis pela felicidade dos cidadãos. Deveriam administrar a polis com os princípios da ética, de acordo com os interesses dos cidadãos.Os gregos não aceitavam completamente as explicações da mitologia sobre a natureza do Universo e do ser humano, através da investigação sistemática. Segundo Platão, o verdadeiro conhecimento advinha na especulação conceitual. Aristóteles, já acreditava que o conhecimento começava com o estudo da realidade. Preocupavam-se com o bom e o belo. Idealizavam o melhor em tudo, a excelência. Superioridade aos demais, dependendo do contexto. No homem, por exemplo, a superioridade é a moral, intelectual e física. A idéia de que qualidade seja sinônimo de nível mais alto continua até hoje.