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The Global ETD Search service is a free service for researchers
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Showing 1 to 2 of 2 (0.095 seconds)Spelling suggestions: "subject:"deformationszon"" "subject:"deformationszone""
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Utvärdering av metod för beräkning av teoretiska sprickvidder för bestämning av tätningsresultat / Evaluation of method for calculation of theoretical fracture apertures for determination of grouting resultsToranian, Adela January 2022 (has links)
When constructing a tunnel, the main challenges are geotechnical and hydrogeological. In the working process the aim in tunneling is to secure the rock mass by sealing the mass before blasting. This is done by grouting. The problem with tunneling is that there is a high leakage of groundwater when the boreholes hits fracture apertures that conduct the groundwater through the rock mass. The water flow is measured in dams continuously throughout the tunneling process. These dams are located at regular intervals along the tunnel. This master thesis has together with Golder and Trafikverket analyzed 15 selected dams. These 15 dams were selected because they had a uniform measurements of flow series for autumn 2020. But also, more important, a new grouting design was implemented in spring 2020. This study is limited to one contract from the project E4 Bypass Stockholm. The evaluated method is based on a backward calculation from grouting data to determine a theoretical fracture apertures. The theoretical fracture aperture is calculated from the rheology of grouting, pressure, and time for grouting but also the predicted fractures during the geological investigations. The hypothesis through the whole master thesis is that high leakage of groundwater correlates with larger fractures in the rock mass, and low leakage of ground water correlates with smaller fractures in the rock mass. Therefore, the leakage was categorized as high leakage and low leakage, respectively for the dams. To investigate this, the theoretical fracture apertures were determined with a calculation tool, MrGrout. This program has the capacity to handle a large amount of data. The result consists of graphical interpretations of the theoretically calculated fracture apertures from each category. The results showed that graphically there was a very small difference between the fractures for high leakage and low leakage, respectively. For the category of high leakage, it was found that 50\% of all fracture apertures were dominated by a size below 250µm. The low leakage had 50\% of the dominated fracture apertures below 200µm. To investigate whether there was a statistically significant difference between the categories the result continued with a T-test. The null hypothesis for the test was that there is no difference. The results of the test showed that we could not reject the null hypothesis and that there is no significant difference. However, the margin was too small to be able to secure the hypothesis graphically. Several assumptions were made to implement the method, which leads to uncertainties. The calculation method is made automatically, which is advantageous when analyzing a large amount of data. The disadvantage of the method is that a manual calculation would have given a more reliable result but also take longer to calculate. A manual calculation had also made the result subjective, which in turn would require several repeated attempts to make a statistically independent evaluation. The conclusion is therefore that the method should be used on other projects to be able to compare whether leakage correlates with fracture apertures in the rock mass. This study does not provide a direct basis for knowing whether we have achieved a sufficient seal. The method is in an early phase to be able to use theoretical fracture apertures in practical decisions for tunneling. / <p>Ämnesgranskare för examensarbetet:<em> Lars M. Hansen</em>, Institutionen för Geovetenskaper.</p>
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Samband mellan geologiska och bergmekaniska egenskaper i bergmaterial som bärlager till riksväg 51 : Riksväg 51 sträckan Svennevad - KvarntorpskorsetLandeman, Philip January 2018 (has links)
This thesis was created to ensure the quality of the rock which would be crushed to base layer construction material, in a road cut at Swedish highway 51, and to find a possible link between the rock's abrasion resistance and its mineralogy. Rock samples were collected, and among other things, several ball mill tests were carried out. The design of the road project was carried out by Loxia Group AB with NCC Group as contractor.A total of 18 rock samples and 2 base layer samples were taken in the area and they were all tested in a ball mill. The results showed that of the 18 rock samples, 2 samples had a ball mill value of less than 16 on the scale, 10 samples had values from 16 to 20, in addition to this, 3 samples had values from 20 to 21 and 3 samples had values in excess of 21 on the Swedish ball mill scale.Of the 3 samples with a ball mill value higher than 21, all contained a larger amount of biotite. Biotite did not appear to the same extent among the samples that ended up further down the ball mill scale. This link was so clear that a conclusion was subsequently drawn from this. The samples taken on the prefabricated base layer both had a ball mill value between 16 and 20. Overall, both the base layer and the rock material passed the Swedish Government’s Transport Administration’s requirements according to "TRVKB 10, Obundna lager". The rock type that was on the south part of the rock cut, adjacent to a deformation zone, had way too poor quality to undergo a ball mill test and therefore there are no values taken from that area.The conclusion of the work is that the rock material overall meets the Swedish Government’s Transport Administration’s requirements for base layer construction materials according to "TRVKB 10 Obundna lager", that a clear link between the proportion of biotite in a rock material and its abrasion resistance exists, and that the broken rock in the south should not be used as construction materials since the rock has insufficient mechanic capacity.
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