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- Andersson, Patrik, 1974, et al.
(författare)
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Framtidsbilder för samhällsbyggnad
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Framtidsbilder för samhällsbyggnad 2020De kommande 15 åren står institutionen för Bygg- och miljöteknik inför stora förändringar. Därför har institutionen initierat projektet Framtidsbilder 2020 där man engagerat en framtidspanel bestående av elva yngre disputerade forskare. Arbetet inleddes med ett breddgruppsmöte där 110 personer representerande institutionens personal och studenter deltog. Vid mötet identifierades ett antal trender och osäkra utvecklingar som påverkar framtiden inom samhällsbyggnadsområdet. Deltagarna bidrog också med idéer till en önskvärd utveckling, vilket har sammanställts och utgör grunden till en gemensam önskvärd framtid/vision för institutionen. Materialet från breddgruppsmötet har bearbetats av Framtidspanelen och resulterat i fyra scenarier som beskriver hur samhällsbyggnadsområdet kan se ut år 2020. Syftet med framtidsbilderna är att de ska vara vägledande för institutionens beslut och förhållningssätt under de kommande åren.Fyra scenarierTurning TorsoSamhället präglas av en ekonomi som är på uppgång, och av ett nytänkande och öppet samhälle. Materiell status och individualism är viktigt. Detta leder till en hög arbetsbelastning samt krav på exklusiva varor av hög kvali-tet. Det finns en stor medvetenhet om miljöpåverkan och klimatförändringar och lösningarna för att klara energiförsörjningen är innovativa.Eco-metropolenDet sveper en grön våg genom dagens samhälle. Under de senaste 15 åren har vi insett att jorden skall vara en bebolig plats även åt dem som kommer efter oss. Vi söker ständigt efter nya, mer förfinade metoder att tillvarata de resurser vi har. Samhället och individen är i balans. Ekonomin är god och vi är miljömedvetna, trygga och integrerade. Nytänkande premieras och icke- materialistiska värderingar står högt i kurs. Vi tänker individuellt, men agerar mer än gärna för kollektivets bästa. Utbildning är gratis TrädgårdsstadenEtt samhälle där vi lärt oss hantera stress, men känner oss otrygga och helst umgås i slutna sociala sammanhang. Vi bor enkelt inne i stan, eller gärna på landsbygden nära storstäderna. Minskade behov av högutbildade i samhället gör att vi har svårt att rekrytera studenter till teknikutbildningar. Det traditionella tankesättet leder till kulturkrockar med företag och personer från andra länder.Gated communitiesFörsämrad ekonomi och ökad egoism har lett fram till ett stressat, otryggt och segregerat samhälle. Accelererande klimatförändringar och ökad miljö-påverkan skrämmer oss, men trots det åtgärdar vi inte problemen, utan koncentrerar oss på konsekvenserna. Arbetslöshet i samhällsbyggnadssek-torn leder till sänkt status för samhällsbyggaren. Vi har därför svårt att rekrytera studenter, och även forskningen har låg status.
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| 2. |
- Axelsson, Magnus, 1974, et al.
(författare)
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Design criteria for permeation grouting in hard rock at great depths
- 2008
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Ingår i: Proceedings World Tunnel Congress 2008, Underground facilities for better environmnet and saftey. ; 1, s. 510-520
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Tidskriftsartikel (refereegranskat)abstract
- Grouting at tunnelling in hard rock at great depths below the groundwater table, when constructing a nuclear waste repository for example, makes special demands on the strength of the grout in order to resist groundwater forces. The aim of this study is to distinguish the most important parameters to ensure that suitable grouting can be performed at large depths. Initially, laboratory studies were conducted in order to determine the most critical parameters. The results from the laboratory tests were used in a field study at the Äspö Hard Rock Laboratory in Sweden. The results indicate that the most important characteristics for the rock are the fracture aperture and the groundwater gradient and for the grout: a resolute grouting pressure and sufficient early strength. This implies that for cementitious grouts the yield stress is important and for non-cementitious grouts it is the shear strength prior to gelling. The results emphasise the need to perform hydraulic characterisation of the rock mass in advance. The results also show the importance of performing a proper grouting, especially at large depths where a decreased penetration length of the grout increases the risk of a high gradient and hence erosion of the grout.
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| 3. |
- Butron, Christian, 1978, et al.
(författare)
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Assessment of the transmissivity field in fractured rock: A case study in the tass tunnel
- 2009
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Ingår i: Nordic Symposium of Rock Grouting.
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Konferensbidrag (refereegranskat)abstract
- Water Pressure Tests (WPTs) among other hydraulic tests were conducted in each borehole before and after the pre-excavation grouting of a test tunnel in the Äspö HRL (Hard Rock Laboratory) built in 2008 and 2009 “the TASS tunnel”. This paper shows how data from WPTs can give information on the connectivity and asses the transmissivity fields of fractured rock. The results showed that the connectivity range of the rock before grouting is approximately 3 m, which seems to be a common range in crystalline fractured rocks. Results clearly indicate that the most conductive parts of each fan were where the grout has penetrated the most during grouting. They also show that the reduction of the transmissivity in the rock by means of grouting is about four orders of magnitude within the studied rock volume of a fan. This sealing takes place easily on planar fractures where the transmissivity is high (a few conductive fractures that give the major contribution to the borehole transmissivity) and what is left unsealed is a highly channelized system. This channelized system will be extremely difficult to hit by future boreholes, which will make post-grouting a very complex task.
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| 6. |
- Funehag, Johan, 1975
(författare)
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Grouting of Fractured Rock with Silica Sol; Grouting design based on penetration length
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACTRecent grouting projects in Sweden have concentrated on the grout itself. The only grout normally used in Sweden is cement-based. During the past 10 years, the acceptable flow of water into tunnels has been reduced significantly. The current requirements mean that an average fracture aperture of around 0.05 mm must be sealed. Chemical grouts generally have a low initial viscosity and the absence of particles means that they can penetrate narrow fractures. Recently, the environmental impact of non-cement grouts has become an important issue. Silica sol is a material that seems to fulfil both requirements, as it is non-hazardous and capable of penetrating narrow fractures.The main objectives of this study are to investigate the basic concepts of how rheology affects penetration and to develop models for calculating penetration length. Other aims are to analyse the need for sealing narrow fractures and to find out how the grouting design can be linked to the characterisation of the rock mass. The papers deal with the grouting procedure with silica sol and analyse a concept for evaluating sealing efficiency and penetration length. In two laboratory studies conducted in a sand-column and pipes, parameters affecting the penetration length were studied. In both studies the aim was to equate the penetration length of the sand and in pipes with that in a slit. For the pipe, the equivalent aperture involves only the radius of the pipe and for the sand the aperture is proportional only to the porosity and calculated specific surface of the sand itself.The five papers outline the grouting procedure with silica sol and suggest a simple grouting model as well as a concept for evaluating the sealing efficiency and penetration length. The grouting design was based on the characterisation of the rock mass and the grouting parameters. A new design criterion for the grouting time was tested and evaluated to obtain a desired penetration length. The grouting time is strongly connected to the gel-time of the grout. The grout used was silica sol, a gelling liquid consisting of amorphous silica particles suspended in water. To initiate and accelerate the gelling process, salt solutions were used. Models were developed to calculate the grout penetration in both one and two dimensions. An interesting feature is that the penetration length calculated in 1-D is about twice as long as that for 2-D, which is verified partially by two field studies. The final penetration is the same as the penetration calculated using the analytical model with a grouting time equal to gel induction time, tG. Since the penetration models are based on the grout properties, the proposed calculations can be applied to most types of gelling liquids, provided the basics of the rheology are taken into account.
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| 7. |
- Funehag, Johan, 1975
(författare)
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Grouting of Hard Rock with Gelling Liquids, Field and Laboratory Studies of Silica sol
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Recent grouting projects in Sweden have concentrated on the grout itself. The only grout normally used in Sweden is a cement-based one. During the past 10 years, the acceptable flow of water into tunnels has been significantly reduced. The current requirements mean that an average fracture aperture of around 0.05 mm has to be sealed. Chemical grouts generally have a low initial viscosity, and the absence of particles means that they can penetrate narrow fractures. Recently, the environmental impact of non-cement grouts has become an important issue. Silica sol is a material that seems to fulfil both requirements, as it is non-hazardous and capable of penetrating narrow fractures.The main objectives of this study are to investigate the basic concepts of how rheology affects penetration and to develop models for calculating penetration length. Other aims are to analyse the need for sealing of narrow fractures and to find out how the grouting design can be coupled to the characterisation of the rock mass. The three papers that make up this study deal with the sealing of narrow fractures in the field. The papers outline the grouting procedure with silica sol and analyse a concept for evaluating sealing efficiency and penetration length. In a laboratory experiment conducted with a sand column, the sand was characterised and the grout penetration was measured. The objective of this experiment was to equate the penetration length of the sand with that in a slit. The hydraulic aperture of a fracture in rock can be used to calculate penetration lengths; the equation derived for the equivalent aperture of the sand is proportional only to the porosity and calculated specific surface of the sand itself. The papers outline the grouting procedure with silica sol and test a concept for evaluating the sealing efficiency and penetration length. The grouting design was based on the characterisation of the rock mass and the grouting parameters. To obtain the desired penetration length, the correct mixing ratio and grouting pressure were determined. The grout used was silica sol, a gelling liquid consisting of amorphous silica particles suspended in water. To initiate and accelerate the gelling process, salt solutions were used. Models were developed to calculate the grout penetration, with dimensionless parameters, in both one and two dimensions. An interesting feature is that the penetration length calculated in 1-D is twice as long as that for 2-D, which is verified partially by two field studies. In the sand column test, the equivalent aperture of the sand is directly linked to the aperture of a fracture. In the second part of the test, the grout penetration stops long before the gel time of the grout is reached. The final penetration is the same as the penetration calculated by the analytical model with a grouting time equal to gel induction time, tG . Since the penetration models are based on the grout properties, the proposed calculations can be applied to most types of gelling liquids, provided the basics of the rheology are taken into account.
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| 8. |
- Funehag, Johan, 1975, et al.
(författare)
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Grouting with silica sol in the Törnskog Tunnel, Grouting design for silica sol in full production
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes a full-scale grouting test in the Törnskog Tunnel. The tunnel is part of the Nordlänken project north of Stockholm, which has two separated tunnel tubes. The test was conducted during production of the tunnel during spring 2005 in chainage from 12012 to 12112. A new concept of grouting was designed and executed based on the grouting material silica sol with the brand name Meyco MP320. Silica sol has been succesfully tested before in field tests in Hallandåsen 2003 and in Äspö HRL 2004. This test is the first test with silica sol in full production of a tunnel in hard rock. The initiative was taken by the National Road Administration, Oden Anläggningsentreprenad and AB BESAB. Design of the grouting procedure were based on a standard tests for characterisation of the rock mass. With use of a pareto-distribution curve, the hydraulic apertures of the fractures could be computed, further the hydraulic apertures was used to estimate the inflows to the tunnel. The demands set on the allowable leakage into the tunnel resulted that hydraulic apertures down to 14 μm needed to be sealed. Cement can penetrate and seal apertures down to 0.05 - 0.1 mm and therefore it was necessary to use a grout material that has a better penetrability, like silica sol. The grout, named Meyco MP320, was chosen and the design parameters were established: grout pressure, gel time, grouting time. The desired penetration was 1.2 m in order to limit unnecessary spread of the grout. The design was different than the traditional grouting methods with demands set on the effective grouting time at a prescribed pressure. All grout fans were carefully monitored using hydraulic tests, before and after grouting as well as control of the actual grouting. Last, the result of the grouting was complemented with a drip characterisation. Two types of grout fans were used. One with the above mentioned grout procedure and one based on the grouting procedure normally used in the Törnskogs Tunnel, but with silica sol instead of cement. The first type fan was used when the rock quality was poor. The other when the rock quality was better. The test with these type fans with silica sol were conducted in one tunnel tube, T201, the other tube was grouted with cement following the standard procedure used in the project. This enabled a comparison of the sealing effect between the cement grouted tunnel tube and silica sol grouted tube.The results of the grouting showed that 8 out of totally 9 grouting fans were successful. The designed fans were used in five cases were the rock mass were presumed to be of poor quality, that is with larger fracture zones present. The objective for this field test was to limit the inflow of water to tunnel corresponding to value of the transmissivity of 3.2ּ10-7 m2/s for the grouted section of 100 m. After grouting the achieved transmissivity was calculated to be 6.2ּ10-7 m2/s. The achieved value of the transmissivity is rather close to the desired; the achieved value considers all fans, including the unsuccessful one. No significant conclusion could be made with the comparison of the sealing effect using cement or silica sol as a grouting agent. The conclusion is that the technique of grouting is very important and more effort needs to be done regarding the grouting time.
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