In this thesis, the results of a number of rock mass classification systems applied to Dim-higway tunnel study area are presented. The tunnel ground was classified according to Rock Mas Rating (RMR), Modified Rock mass Rating (M-RMR), Rock mass quality (Q), Geological Strength Index (GSI) and New Austrian Tunneling Method (NATM). Dim Tunnel has a horse-shoe shape, with a diameter of 10 meters and maximum overburden thickness of 70 meters. During studies, the geological and geotechnical characteristics of the rock mass along the Dim Tunnel route were investigated. The main objective of rock mass classifications carried out in this study was to obtain adequate data that could be used in future excavation and support-design studies. In order to accomplish this task, literature survey was carried out, followed by a comprehensive field study and laboratorytesting. Field studies involved detailed discontinuity surveys of the exposed rock mass at the surface and on the cores taken within 10-20 meters of the borehole above the tunnel. A geological map and a geological cross-section along the tunnel axis were also prepared. Finally, correlations between the results of the rock mass classification systems were made carrying out statistical analyses for the Dim Tunnel study area. The results obtained from the RMR and M-RMR classifications indicate that M-RMR system estimates better rock mass quality ratings at the upper bounds of the rock mass condition, but worst ratings at the lower bounds (RMR is less than 40) as also suggested by the previous studies.

Com a abertura do setor de geração de energia elétrica no país houve um aumento do número de projetos para pequenas centrais hidrelétricas - PCHs. Os estudos geológico-geotécnicos necessários para este tipo de obra tiveram que se adaptar às necessidades deste novo setor, sem haver perda da qualidade. O objetivo deste trabalho foi o aprimoramento dos estudos de compartimentação geológico-geotécnicos, utilizando um dos sistemas de classificação de maciços rochosos mais conhecidos: o Sistema RMR - rock mass rating - (Bieniawski, 1973), analisando as vantagens, as desvantagens, e o potencial de aplicação do método. A pesquisa foi aplicada na PCH Morro Grande, localizada no Rio Grande do Sul, que apresenta uma grande homogeneidade geológica, sendo o embasamento constituído por derrames basálticos da Formação Serra Geral. Foram propostas algumas modificações na forma de aplicação do sistema RMR, como não pré-compartimentar o maciço, aplicar a classificação diretamente nos testemunhos de sondagem e de forma parcial nos afloramentos, e substituir o RQD (rock quality designation) pelo IQR (índice de qualidade da rocha). Para caracterizar a resistência da rocha foram feitos ensaios de compressão puntual, associados aos diferentes graus de alteração da rocha. O resultado foi apresentado em seções do eixo da barragem e do circuito hidráulico. A metodologia proposta resultou na compartimentação detalhada do maciço rochoso, na área das estruturas da PCH, mostrando-se uma ferramenta útil para a determinação da compartimentação de maciços rochosos, principalmente de maciços homogêneos, podendo ser aplicadas de forma rápida e a um custo baixo para o projeto. / The opening of the electric production sector in Brazil causes an increase amount of Small Hydroelectric Power Station - PCH\'s - project. The necessaries geological-geotechnical studies for this kind of construction had to be adapted to this new sector necessity, without quality losses. This research aim was the improvement of the geological-geotechnical studies, using one of the most well-known rock mass classification systems: the RMR system - rock mass rating - (Bieniawski, 1973), and analyze the advantage, the disadvantage, and potential of this method application. This research was applied to Morro Grande PCH, located on Rio Grande do Sul state - Brazil, which has great geologic homogeneity, and its rock foundation is basaltic rocks of the Serra Geral Formation. Some modification in the RMR application way has been proposal, like don\'t pre-divide the rock mass, apply the system directly in the core logging and partially to the outcrops, and change RQD (rock quality designation) by IQR (rock quality index). To rock strength have been established by point-load test, for the different weathering degrees of the rock samples. The results are presented on profiles of the structures axis. The propose method resulted in detailed compartimentalization of the structures areas, turning into an useful tool to assist the rock mass analyses, mainly to homogeneous rock masses, been applied quickly and at low costs.

Com a abertura do setor de geração de energia elétrica no país houve um aumento do número de projetos para pequenas centrais hidrelétricas - PCHs. Os estudos geológico-geotécnicos necessários para este tipo de obra tiveram que se adaptar às necessidades deste novo setor, sem haver perda da qualidade. O objetivo deste trabalho foi o aprimoramento dos estudos de compartimentação geológico-geotécnicos, utilizando um dos sistemas de classificação de maciços rochosos mais conhecidos: o Sistema RMR - rock mass rating - (Bieniawski, 1973), analisando as vantagens, as desvantagens, e o potencial de aplicação do método. A pesquisa foi aplicada na PCH Morro Grande, localizada no Rio Grande do Sul, que apresenta uma grande homogeneidade geológica, sendo o embasamento constituído por derrames basálticos da Formação Serra Geral. Foram propostas algumas modificações na forma de aplicação do sistema RMR, como não pré-compartimentar o maciço, aplicar a classificação diretamente nos testemunhos de sondagem e de forma parcial nos afloramentos, e substituir o RQD (rock quality designation) pelo IQR (índice de qualidade da rocha). Para caracterizar a resistência da rocha foram feitos ensaios de compressão puntual, associados aos diferentes graus de alteração da rocha. O resultado foi apresentado em seções do eixo da barragem e do circuito hidráulico. A metodologia proposta resultou na compartimentação detalhada do maciço rochoso, na área das estruturas da PCH, mostrando-se uma ferramenta útil para a determinação da compartimentação de maciços rochosos, principalmente de maciços homogêneos, podendo ser aplicadas de forma rápida e a um custo baixo para o projeto. / The opening of the electric production sector in Brazil causes an increase amount of Small Hydroelectric Power Station - PCH\'s - project. The necessaries geological-geotechnical studies for this kind of construction had to be adapted to this new sector necessity, without quality losses. This research aim was the improvement of the geological-geotechnical studies, using one of the most well-known rock mass classification systems: the RMR system - rock mass rating - (Bieniawski, 1973), and analyze the advantage, the disadvantage, and potential of this method application. This research was applied to Morro Grande PCH, located on Rio Grande do Sul state - Brazil, which has great geologic homogeneity, and its rock foundation is basaltic rocks of the Serra Geral Formation. Some modification in the RMR application way has been proposal, like don\'t pre-divide the rock mass, apply the system directly in the core logging and partially to the outcrops, and change RQD (rock quality designation) by IQR (rock quality index). To rock strength have been established by point-load test, for the different weathering degrees of the rock samples. The results are presented on profiles of the structures axis. The propose method resulted in detailed compartimentalization of the structures areas, turning into an useful tool to assist the rock mass analyses, mainly to homogeneous rock masses, been applied quickly and at low costs.

Detta examensarbete genomfördes i samarbete med Trafikverket och analyserar möjliga orsaker till avvikelser mellan karaktärisering utförd på kärnborrhål vid förundersökningar, uppförande av ingenjörsgeologisk prognos och karaktärisering och klassificering utförd i tunnel vid byggnadsskedet för Citybanan. Två av projektets delentreprenader utvärderades – Norrströms- och Norrmalmtunneln. Totalt analyserades 4596 löpmeter tunnel (Norrströmstunneln) och 2557 meter (Norrmalmstunneln) i syfte att identifiera varför och vart i processen som avvikelser uppstod. Den utförda studien tyder på att inom de två undersökta delentreprenaderna uppstod en skillnad i resultat mellan karaktärisering utförd i kärnborrhål och karaktärisering och klassificering utförd i tunnel. Övergripande visar resultat från karaktäriseringen i samband med tunnelkartering generellt sämre bergförhållanden jämfört med det som prognostiserats. Skillnaderna  otsvarade sämre förhållande uttryckt i 5 (för Norrströmstunneln) respektive 7,5 enheter (Norrmalm) i RMR-systemet från borrhål till tunnelkaraktärisering. Analysen av det utvärderade resultatet indikerar att avvikelserna mellan karaktärisering på borrkärnor jämfört med karaktärisering och klassificering utförd i tunnel antagligen till viss del beror på den använda metodiken vid karaktärisering och klassificering av bergkvaliten med RMR- och Q-systemet. Detta på grund av att parametrarna i systemen inte bestäms på exakt samma sätt vid karaktärisering i förundersökningsskede och karaktärisering och klassificering i byggnadsskede. Dessutom indikeras att anvisningarna för karteringsrutiner vid karaktärisering och klassificering hanteras olika av karterande geologer vid tunneldrivning. Baserat på resultaten från den utförda analysen diskuteras även om det för vissa parametrar för karaktärisering och klassificering finns ett behov av uppdatering i den använda metodiken. Detta för att få förundersökningsprocessen att samspela med det arbete som sker i en tunnel. Resultaten tyder också på att geologerna vid tunnelkartering har en tendens till att kartera sämre bergförhållanden jämfört med det som är prognostiserat samt att vissa egenskaper hos berget kan vara lättare att beskriva på plats i tunneln än vid karaktärisering av berget från en borrkärna. Genom att harmonisera processen för beskrivning av ingående parametrar i de system som används vid karaktärisering mellan förundersökning och karaktärisering och klassificering i byggskede kan skillnader mellan stegen reduceras och risken för prognosavvikelser kan minska för tunnelprojekt i framtiden. / This thesis was carried out in cooperation with the Swedish Transport Administration and analyzes the possible causes of differing rock mass quality assessed in boreholes, engineering geological forecast and tunnel mapping. Two contracts from the City Line project where investigated - in total has 4596 meters (the Norrström tunnel) and 2557 meters (the Norrmalm tunnel) of tunnel mapped during construction been analyzed. The purpose was to identify the reason and where differences in the process of rock evaluation arose. The performed study indicates that in the two investigated tunnels it arose a difference in the results between the characterization performed in boreholes and the subsequent geological forecast compared with the characterization in the tunnel. The assessed rock mass quality became generally successively poorer as the process progresses. This was particulary the case when comparing the geological forecast with tunnel mapping during construction The differences corresponded to a difference of a downgrade of 5 (for the Norrström tunnel) and 7,5 units (the Norrmalm tunnel) in the RMR-system from bore holes to tunnel mapping. The analysis of the evaluated results indicates that the differences between the characterization of boreholes and geological forecasts compared to the characterization and classification performed in the tunnel is probably due to the methodology in the characterization and classification of rock quality with the RMR- and Q system. This is because the parameters of the  ystems is not determined exactly in the characterization of the preliminary investigation stage and the characterization and classification in the construction stage. Also the instructions for mapping routines for the characterization and classification are handled differently by the mapping made by geologists during tunneling. Based on the results of the analysis it is recommended that the way in which some parameters in the systems of characterization and classification of rock are determined should be updated. This is in order to standardize the process for characterizing the rock mass when mapping boreholes, creating geological forecast and conducting tunnel mapping. It is also indicated  that geologists tend to conservatively scale down the rock quality in the tunnel and that certain features of the rock is easier to determine in the tunnel than during characterization of bore holes. By harmonizing the description of parameters of the systems used in the characterization of bore holes and characterization and classification in the construction stage, differences between the steps can be reduced for projects in the future.