| 1. |
- Fransson, Åsa, 1971, et al.
(författare)
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Characterization of fractured crystalline rock: two Swedish in situ field experiments
- 2014
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Ingår i: 1st International Discrete Fracture Network Engineering Conference, 20-22 oct 2014, Vancouver, Canada.
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Konferensbidrag (refereegranskat)abstract
- Construction of a nuclear waste repository requires information and an understanding of the fractured rock. The Swedish concept for nuclear waste deposition that is currently being developed by the Swedish Nuclear Fuel and Waste Management Co (SKB) includes a natural barrier in the form of crystalline rock, and engineered barriers in the form of bentonite and a copper canister. This paper aims to present two in situ field experiments: the first is the Large fractures experiment and the second is BRIE, the Bentonite Rock Interaction Experiment. Important issues include possible deformation (shearing) of fractures and deformation zones influencing the localization of canisters, and fluid flow, resulting in hydration of the bentonite. The aim of Large fractures is to further develop strategies and integrated investigation and modelling methodology for the identification and characterization of geological structures to ensure that (size) determination of large fractures or minor deformation zones to a greater extent can be based on real properties and to a lesser degree on a criterion related to the existence of a full perimeter fracture – tunnel intersection. BRIE is a field experiment which addresses the hydraulic interaction between the system components of compacted bentonite and the near-field host rock composed of hard and fractured bedrock. The above experiments are presented in terms of investigations performed to obtain discrete fracture descriptions. Grouting of fractures intersecting the investigation borehole of the Large fractures experiment was designed based on field data and a decrease in flow from above 200 liters/min to below 1 liter/min was achieved. The magnitude of the transmissivity of the fracture/deformation zone that was grouted indicates a large fracture size. This is also indicated by the ongoing integrated interpretation (geology, hydrogeology and geophysics). Results from BRIE show that hydration is uneven and is controlled by the main conductive fracture, highlighting the need for a relevant fracture description.
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| 2. |
- Funehag, Johan, 1975, et al.
(författare)
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Grundläggande egenskaper för injektering och inträngning av bruk
- 2014
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Ingår i: Bergmekanikdag 2014, Stockholm.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Injektering i hårt berg inkluderar vetenskaper som flöde av vätskor, reologi, hydrogeologi, material kännedom, geologi och annat. Att faktiskt förstå och ha en känsla för hur flöde fungerar i sprickor är viktigt. Detta kan lätt glömmas av och energi läggs allt som oftast på andra delar exempelvis på materialetkunskap. Denna artikel syftar till att beskriva hur flöde sker i sprickor och bör kunna bidra till en känsla av hur flödet av bruk faktiskt sker. Artikeln utgår från framtagna samband för spridning baserat på Binghamflöden för att beskriva hur yttre händelser som kan uppträda vid vanlig injektering kan påverka spridningen. En verifikation av inträngningslängder i en nyligen tillverkad sprickmodell används för att visa hur ett Binghamflöde beter sig. Både spridning och hur ett sambandshål påverkar spridningen visas samt hur detta kan påverka designkriterier. Filmvisning av injekteringsflöde i sprickrepliken kommer säkerligen bringa lite mer klarhet i hur teoretiska beräkningar kan användas som modeller.
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| 3. |
- Thörn, Johan, 1986, et al.
(författare)
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Fracture Deformation Measurements during Grouting in Hard Rock
- 2012
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Ingår i: Geotechnical Special Publication. - Reston, VA : American Society of Civil Engineers. - 0895-0563. - 9780784412350 ; :228 GSP, s. 836-845
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Konferensbidrag (refereegranskat)abstract
- When a fracture system in crystalline rock is grouted the rock mass may deform. Such deformations may reduce the grouting efficiency since new flow paths are opened. The work presented here show that deformations occur at hydraulic tests and grouting and that deformation can be measured and evaluated as stiffness from in situ tests. Deformation measurements, hydraulic testing, and grouting was conducted in spring 2010 in the Hallandsås tunnel and hydraulic testing in a service tunnel in Gothenburg (Runslätt and Thörn, 2010). For measuring physical deformation recently developed equipment from Chalmers University of Technology was used. Deformations were measured seven times in the same borehole. Three measurements were during grouting, and the remaining four from water pressure tests. Most deformations occurred at pump pressures of 1-1.4 MPa, which is lower than the calculated normal rock stress. Stiffness has been evaluated in several ways, including a new method, (Fransson, et al., 2010). Generally the evaluated stiffness is lower in the Hallandsås tunnel than in the Gothenburg tunnel. The results show agreement with other in situ experiments.
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| 4. |
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| 5. |
- Fransson, Åsa, 1971, et al.
(författare)
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Hydromechanical characterization of fractures close to a tunnel opening: A case study
- 2012
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Ingår i: ISRM International Symposium - EUROCK 2012.
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Konferensbidrag (refereegranskat)abstract
- Important factors influencing the hydromechanical behavior of a fracture are in situ rock stresses (natural and induced) as well as hydraulic heads, fracture orientation, connectivity and fracture geometry, including their infillings. Particular attention is given to larger, water-conducting fractures that intersect or are close to a tunnel. For the Bentonite Rock Interaction Experiment (BRIE) at the Äspö Hard Rock Laboratory (HRL) in Sweden, the interaction between rock and bentonite in a deposition borehole is of particular interest. The BRIE experiment is being conducted at a depth of 420 meters in crystalline rock. This paper presents results from the initial identification, characterization and modeling of a small number of fractures close to the tunnel opening. So far, these fractures have been identified as the most important water-conducting fractures. In this identification and characterization exercise, core-drilled, vertical, three-meter deep investigation boreholes were made in the tunnel floor. Logging of natural hydraulic heads in boreholes and hydraulic tests, along with borehole and tunnel mapping in combination with modeling, indicate small deformations. This was also confirmed by deformation measurements performed in the boreholes. The description of the site will be further updated and revised and additional investigations into the link between stress history, fracture geometry and selection of fracture mechanical properties will be of particular interest.
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| 6. |
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| 7. |
- Thörn, Ingrid, et al.
(författare)
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Applicability of IG/TCR gene rearrangements as targets for minimal residual disease assessment in a population-based cohort of Swedish childhood acute lymphoblastic leukaemia diagnosed 2002-2006.
- 2010
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Ingår i: European journal of haematology. - : Wiley. - 1600-0609 .- 0902-4441. ; 84:2, s. 117-27
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Tidskriftsartikel (refereegranskat)abstract
- Minimal residual disease (MRD) detection during the early treatment phase has become an important stratification parameter in many childhood acute lymphoblastic leukaemia (ALL) treatment protocols. Here, we aimed to address the applicability of rearranged antigen-receptor genes as potential MRD markers using real-time quantitative polymerase chain reaction (RQ-PCR) in a Swedish population-based cohort. From 334 childhood ALL cases diagnosed during 2002-2006, we analysed 279 diagnostic samples (84%) by screening for rearranged immunoglobulin (IG) and T-cell receptor (TCR) genes. Allele-specific oligonucleotides were designed, and the sensitivity and quantitative level was determined for each target. Overall, clonal IG/TCR rearrangements were detected in 97% (236/244) of B-cell precursor ALL (BCP ALL) and 94% (33/35) of T-ALL. A sensitive RQ-PCR analysis (< or = 10(-4)) was obtained in 89% (216/244) of BCP ALL and in 74% (26/35) of T-ALL, whereas two sensitive targets were only available in 47% (115/244) of BCP ALL and 29% (10/35) of T-ALL cases. With the stratification threshold of > or = 10(-3), which is applied in the current Nordic treatment protocol (NOPHO-ALL 2008) for the identification of high-risk patients, 93% of BCP ALL and 86% of T-ALL reached this quantitative range by at least one target gene. Taken together, this national retrospective study demonstrates that an IG/TCR target for MRD monitoring can be identified in the majority of childhood ALL cases, whereas identification of a second sensitive target gene needs to be improved.
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| 8. |
- Thörn, Johan, 1986, et al.
(författare)
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Assigning Fracture Stiffness from In-Situ Deformation Measurements
- 2014
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Ingår i: 1st International Discrete Fracture Network Engineering Conference, 20-22 oct 2014, Vancouver, Canada.
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Konferensbidrag (refereegranskat)abstract
- Fracture stiffness is varying between fractures and is influenced by its proximity to a tunnel opening; if the behavior close to the opening is of interest for modelling efforts, then it may be better to use such data as input rather than high-stress laboratory measurements. A handy method for in situ testing of deformation (stiffness) and transmissivity would be beneficial to obtain data for numerical modeling of the near field of an excavation. We describe a measurement method under development that uses an anchor in a borehole and measures deformations between the anchor and the rock surface. Measurement of deformations is done during a stepwise constant head injection test providing information about both hydraulic and mechanical properties. Deformations and applied pressure is used through the effective stress concept to calculate fracture stiffness. Deformation measurements have been conducted in the TASO and TAS04 tunnels at 410 – 420 m depth at Äspö Hard Rock Laboratory (HRL), and in the Hallandsås tunnel, Sweden. Results show deformations in tested fractures 0.2 – 3 m below tunnel floor in the order of a few to tens of micrometers for injection overpressures in the order of 0.5 – 0.6 MPa. Stiffness is traditionally described as either normal stiffness or shear stiffness, the design of the experimental setup here does not allow for this distinction directly from the results; however knowledge of the orientation of tested fractures and coupling of the results to injection rates may help in discerning type of deformation.
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| 9. |
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| 10. |
- Thörn, Johan, 1986, et al.
(författare)
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Fracture Aperture Measurement and Consequences for Grouting
- 2013
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Ingår i: Proceedings of the 7th Nordic Grouting Symposium, Gothenburg, Sweden. - 9789163708787 ; , s. 183-193
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Konferensbidrag (refereegranskat)abstract
- The hydraulic and the mechanical apertures of fractures and the relation between them are of interest for hydromechanical (HM) coupling and design of grouting works and reinforcement. The fracture geometry will influence water inflow to underground constructions, penetrability and penetration length of grout and mechanical properties of the fracture. This paper aims at presenting fracture geometry measurements on one fracture sample and to use this as a basis for a discussion on consequences for grouting. To measure surface topography of the two sides of a rock core fracture sample from the TASS-tunnel, Äspö HRL (Sample and sampling described in Ericsson et al. 2009) commercial equipment for stereo photogrammetry was used. Prior to scanning each surface, their relative positions were determined at 1.0 MPa confining pressure. The procedure enables a computer comparison between the surfaces, rendering an aperture map for the specific confining pressure. The measured surface geometry provided a data set that was put in the context of hydraulics, mechanics and hydromechanics. Comments on how the applications inflow, grout spread, fracture deformation and block stability can be related to the fracture geometry are given.
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