This thesis comprises a study of the gyroscope and the gyrotheodolite, tunnel control networks and a case study of geodetic reference networks and survey methods in the Project Hallandsås. The Project Hallandsås is a railroad tunnel project through the ridge of Hallandsås in the south of Sweden. Two parallel, 9 kilometres long, tunnels are to be constructed. The railway through these tunnels will smooth a difficult section of the Swedish main western railroad. The tunnel is excavated and lined with enforced concrete using a Tunnel Boring Machine (TBM).The demands of accuracy of geodetic reference networks in a tunnel projectare high and in projects using TBM:s, even higher. The total breakthrough accuracy in Project Hallandsås is ± 100 mm. Of this the surveys may use half of this tolerance, i.e. ± 50 mm. The possibility to do accurate surveys and establish accurate reference network are limited. In the normal case when construction takes place on the surface, the first thing that is done is to establish a site-specific geodetic network. The networks are connected to national networks or other regional networks surrounding the construction site.To have a superordinate site-specific geodetic network is also possible for a tunnel project. The differences begin with the establishment of working/construction networks below the superordinate network through densification of higher project networks. In the surface construction case it ispossible to connect the surveys to points that surround the construction area and once the networks are adjusted and checked for errors toward all points, construction may begin. This last procedure is not possible when a tunnel is excavated.However, there are methods to optimise the tunnel control network. This thesis will look at some of these methods, particularly on how different configurations of network affect the breakthrough accuracy and possibility to check the networks through redundant surveys. The gyro instrument, correctly used, is one of the most important methods to both check and improve the accuracy of the tunnel control network.The studies in this thesis will show that the breakthrough error of an open end traverse is much improved by using gyro observations, and that a more redundant network is also improved but to a lower degree. We will also seethat the gyro observations plays a significant role in checking the open-ended traverse for errors even though more redundant network will always be betterfor the checking and elimination of errors. This thesis will only discuss surveys in the plane coordinate system.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-176300 |
| Date | January 2006 |
| Creators | Lewén, Ingemar |
| Publisher | KTH, Geodesi och satellitpositionering |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-GIT EX ; 06-002 |
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