Vägverket gör idag stora investeringar i nya tekniker för att förbättra tätningen av tunnlar från vattenläckage. Allt eftersom kraven på tätning har ökat, liksom antalet tunnlar i urbana miljöer, ökar också intresset i ny teknologi för tunneltätning. När tätningen misslyckas kompletteras den vanligtvis med dräner som sätts upp i tunneltaket och leder bort inläckage. Dessa är dock dyra och kräver mycket underhåll. En viktig del i Vägverkets arbete är därför att följa upp användningen av nya tätningsmetoder för att kunna avgöra om de verkligen är bättre än mer beprövade metoder som t.ex. cementinjektering. Syftet med examensarbetet är att, för Vägverkets räkning, utvärdera tätningsmetoderna i tre olika tunnlar. Den första är Törnskogstunneln, som byggts för Norrortsleden norr om Stockholm, där cement- och keminjektering med Silica Sol använts tillsammans med tillsatsmedlet Xypex i olika kombinationer. Den andra är Löttingetunneln, också den en del av Norrortsleden, där klassisk cementinjektering använts. Sist är Ullbrotunneln, väster om Enköping, där tillsatsmedlet Penetron använts tillsammans med en kortare referenssträcka utan. Utvärderingen kommer att belysa respektive metod ur tätningssynpunkt och deras kostnader per meter för att kunna säga vilken som varit mest prisvärd. Data har samlats in i form av priser för de olika tätningskoncepten, vilka mängder som behövts och de geologiska förutsättningarna i form av vattenförlustmätningar ur kärnborrhål och injekteringsskärmar, samt RQD-värden från geologernas karteringar. Dessutom har en utförlig droppkartering genomförts under byggskedet av Ullbrotunneln för att bedöma hur mycket tätare sprutbetongen blir vid användning av Penetron som tillsatsmedel. Slutsatsen av undersökningarna är att användningen av Xypex både visat sig dyrare och sämre på att täta Törnskogstunneln än de sträckor av tunneln där klassisk injektering använts. Användningen av Silica Sol är svårare att dra klara slutsatser om då det i ena fallet visat sig täta bättre och kosta mindre än vanlig injektering medan det i kombination med Xypex var dubbelt så dyrt och ändå inte lika effektivt.Användningen av Penetron kan inte ses som helt framgångsrik då den inte lyckats täta Ullbrotunneln fullständigt. Även om droppet minskat kraftigt sen appliceringen av sprutbetongen har även referenssträckan utan Penetron minskat i dropp. Alltså går det inte att säga om Penetron gjort någon skillnad när ett lager vanlig sprutbetong tätar lika bra. I utvärderingen finns även en ansats till att sammanväga de olika förutsättningarna och resultaten av tunneltätningarna i en enda parameter för att öka jämförbarheten mellan olika projekt. Detta effektivitetstal, som parametern kallas, gav en ytterligare dimension till utvärderingen men behöver utvecklas mer innan den kan användas i verkligheten med tillförlitlighet. / The Swedish Road Administration is currently making large investments in new technologies to improve the sealing of tunnels from water ingress. As the sealing requirements increase, as well as the number of tunnels in urban areas, so does the interest in new sealing technology. When sealing fails the standard procedure is to place geomembranes on the ceiling which diverts the seepage. However, these are expensive and require a lot of maintenance. Consequently, an important part in the work of the Swedish Road Administration is to administer follow-ups on new sealing techniques in order to decide whether they are an improvement from tested methods like cement-grouting. The purpose of the thesis is, on account of the Swedish Road Administration, to evaluate the sealing methods of three different tunnels. The first is the Törnskogstunnel, a part of Norrortsleden north of Stockholm, where cement and chemical grouting with Silica Sol has been used with the admixture Xypex in different combinations. The second is the Löttingetunnel, also a part of Norrortsleden, where classic cement grout has been used. Last is the Ullbrotunnel, west of Enköping, where the admixture Penetron has been used together with a shorter reference section without additive. The evaluation will explain each method from the perspective of sealing effectiveness and cost per meter tunnel, in order to decide which product is the most cost-efficient. The collected data for the evaluation are; prices for each method, which amounts were necessary and geological conditions in terms of water-loss measurements from core drill holes and grouting fans, as well as RQD-values from the geologists’ evaluations. In addition, a more elaborate mapping of the seepage in the Ullbrotunnel has been made during its construction in order to decide the effectiveness of Penetron in making shot-concrete waterproof. The conclusion after the evaluations is that Xypex proved itself to be both more expensive, as well as less effective in sealing the tunnel, compared to the parts of the tunnel where classic cement-grouting was used. Regarding Silica Sol it was more difficult to make any evident conclusions as it was both cheaper and more effective in one part of the tunnel, while together with Xypex the cost was doubled and yet less effective.The use of Penetron cannot be regarded as totally successful as it didn’t seal the Ullbrotunnel completely. Even though the seepage was significantly reduced after the application of the shot-concrete the seepage in the reference section was also reduced. Thus, it is impossible to say whether the Penetron has made a difference when the normal shot-concrete is equally waterproof. In the evaluation there is also an attempt to weigh the various circumstances and results of the sealing process into one single parameter to facilitate the comparison between different projects. This efficiency rate, as the parameter is called, gave a further dimension to the evaluation, but need more development before it can be used in real projects with any confidence. / QC 20101109

When building tunnels in rock, an inflow of groundwater is likely induced. Depending on the hydraulic properties of the rock and the surrounding soils, the inflow may cause a decline in the groundwater level above the tunnel line with possible consequences for nearby well facilities or groundwater dependent environments. Discharge of the inflowing groundwater represents an operation of water (vattenverksamhet in Swedish) according to the Swedish environmental law, meaning that permission must be applied for at the Environmental Court. In the application, the operator presents an area of influence for groundwater, which defines the area where the groundwater levels could change due to the planned operation. In this work, the area of influence has been defined as the area where the groundwater level is lowered by more than five centimeters. As part of the project Tvärförbindelse Södertörn in southern Stockholm, the Swedish Transport Administration is planning for the construction of a tunnel in rock adjacent to Glömstadalen in Huddinge municipality. The aim of this master thesis was to investigate the extension of the area of influence of the tunnel through two-dimensional groundwater modelling. A site-specific model was created in the program SEEP/W by establishing a cross-section orthogonal to the tunnel and through examination of the hydrogeological conditions in the area. Steady-state modelling of both unsaturated and saturated flow was then carried out including and excluding the tunnel. Through this, the change in groundwater levels due to the tunnel could be reviewed. Since the development of the model required simplifications and assumptions of the site-specific conditions, a simple sensitivity analysis was also performed where a few model parameters were altered to examine how the area of influence changed. The modelling results showed that the tunnel, when sealed suitably, at most changed the groundwater levels 680 meters north and 840 meters south along the studied cross-section. The smallest effect on the groundwater levels was observed 400 meters north and 560 meters south of the tunnel. Differences in the extension of the area of influence were noticed depending on how the outflow of groundwater in Glömstadalen was represented, and which sealing properties around the tunnel were used. Furthermore, the modelling showed that the hydraulic conductivity of the rock is of major importance for the location of the groundwater table, and therefore it is considered relevant to perform hydraulic tests in the rock to increase the reliability of the model.