Utvärdering av de geotekniska undersökningarna för Citylink tunneln i Stockholm: Studie av sonderingsmetoder samt sonderingsförfarande på vatten
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Combining several different investigation methods within one project is something that is done on a daily basis. This master thesis analyses results from a project where methods that are relatively unusually within the geotechnical society are combined. The sounding program was also almost entirely executed on water.In the thesis geotechnical investigations performed by Vectura Consulting for the City Link project are evaluated. The City Link project is a TBM driven tunnel under the city of Stockholm, and the investigations was performed on the behalf of “Svenska kraftnät”. The thesis is performed on behalf of Vectura in Sundsvall where Per Nilsson has driven the issues which are the subject of this thesis.The methods used in the project has been soil-rock sounding, reflection- and refraction seismic, MWD-guided down the hole drill (DTH) and core drilling sampling. Every sounding except the core drilling sampling has been conducted on water. The core drilling sampling has in this thesis been infringed for the other methods. Complications and solutions regarding the performed sounding on water were found during the project, which resulted in a list of recommendations for performing sounding on water. Soil-rock sounding has been linked to the performed refraction seismic to investigate whether the seismic inferred rock quality could be shown in the soil-rock sounding. The analysis shows that it strongly tends to be possible, although more studies have to be done to confirm this theory. The study also shows the importance of having a seismic survey within a large scale geotechnical investigation where the bedrock level is of interest.MWD-guided down the hole drill is, within the geotechnical society, an uncommon method for rock-sounding. In this project the DTH were carried out on the sounding points where soil-rock sounding was estimated not to be possible to use, because of too large sounding depths. The aim of the investigations where to find the bedrock surface, which it also did. Further analysis also indicates that the rock quality in relation to all executed DTH soundings within the project could be distinguished.For both soil-rock sounding and DTH the method to integrate the sink rate and to form an index has given a simpler graphical interpretation of the soundings. The index which is formed by the driving force and the sink rate has also, and can be used to interpret the rock quality. The study also showed some significance regarding the weight of the sounding rods, especially for rock-soil sounding.
Place, publisher, year, edition, pages
2013. , 107 p.
Teknik, Jb-sondering, MWD, utvärdering, seismik, sänkhammarborrning, sondering på vatten
IdentifiersURN: urn:nbn:se:ltu:diva-48876Local ID: 64ac4687-d262-479f-9530-ca796a683ab7OAI: oai:DiVA.org:ltu-48876DiVA: diva2:1022220
Subject / course
Student thesis, at least 30 credits
Civil Engineering, master's level
Validerat; 20130609 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved