The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen
When planning for a tunnel, the ground conditions in which the tunnel is going to be excavated through will be investigated to different extent. Lack of relevant pre-investigation data or misinterpretations of the available data can cause both economical and/or unexpected stability problems. Weaknes...
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Luleå tekniska universitet, Geoteknologi
2016
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ftluleatu:oai:DiVA.org:ltu-59939 2023-05-15T15:45:27+02:00 The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen Svaghetszoners påverkan på tunnelstabilitet baserat på undersökningar i Bodötunneln Renström, Viktor 2016 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59939 eng eng Luleå tekniska universitet, Geoteknologi http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59939 info:eu-repo/semantics/openAccess Rock mechanics Numerical modeling Geology Geologi Geophysics Geofysik Geotechnical Engineering Geoteknik Student thesis info:eu-repo/semantics/bachelorThesis text 2016 ftluleatu 2022-10-25T20:52:52Z When planning for a tunnel, the ground conditions in which the tunnel is going to be excavated through will be investigated to different extent. Lack of relevant pre-investigation data or misinterpretations of the available data can cause both economical and/or unexpected stability problems. Weakness zones that are expected to cross the tunnel could be investigated thoroughly with a variety of methods. Refraction seismicity survey and 2D resistivity survey are two geophysical methods that are common in Norway for obtaining information about the rock quality in weakness zones. In this work, a twin tunnel under construction in Bodø (northern Norway) called the Bodøtunnel is studied. The predictions based on the pre-investigation for crossing of some expected weakness zones are compared to the actual conditions encountered during tunneling. Tunneling observations (Geological mapping and photos), rock samples and measurement while drilling (MWD) were used to describe the weakness zones that were encountered during tunneling. Rock samples were collected from two weakness zones and the general rock mass. These samples were tested in a point bearing machine for determination of their uniaxial compressive strength (UCS). These results indicated that the rock samples gathered from the weakness zones had significantly lower UCS than the samples from the rock mass. This was exceedingly clear for the samples of fault rock gathered in connection with a shear zone. The results from this work demonstrate that refraction seismicity had a high success rate for locating weakness zones, with the exception for the crossed narrow zones that were interpreted lacking a shear component. Empirical formulas relating Q-value and UCS with the seismic wave speed were used for calculating these factors for some interesting locations. The empirically calculated UCS was similar to the obtained UCS from the point bearing tests, while the empirically calculated Q-value showed large deviations from the mapped Q-value. The resistivity measurements ... Bachelor Thesis Bodø Bodø Northern Norway Luleå University of Technology Publications (DiVA) Bodø ENVELOPE(14.405,14.405,67.280,67.280) Norway |
institution |
Open Polar |
collection |
Luleå University of Technology Publications (DiVA) |
op_collection_id |
ftluleatu |
language |
English |
topic |
Rock mechanics Numerical modeling Geology Geologi Geophysics Geofysik Geotechnical Engineering Geoteknik |
spellingShingle |
Rock mechanics Numerical modeling Geology Geologi Geophysics Geofysik Geotechnical Engineering Geoteknik Renström, Viktor The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen |
topic_facet |
Rock mechanics Numerical modeling Geology Geologi Geophysics Geofysik Geotechnical Engineering Geoteknik |
description |
When planning for a tunnel, the ground conditions in which the tunnel is going to be excavated through will be investigated to different extent. Lack of relevant pre-investigation data or misinterpretations of the available data can cause both economical and/or unexpected stability problems. Weakness zones that are expected to cross the tunnel could be investigated thoroughly with a variety of methods. Refraction seismicity survey and 2D resistivity survey are two geophysical methods that are common in Norway for obtaining information about the rock quality in weakness zones. In this work, a twin tunnel under construction in Bodø (northern Norway) called the Bodøtunnel is studied. The predictions based on the pre-investigation for crossing of some expected weakness zones are compared to the actual conditions encountered during tunneling. Tunneling observations (Geological mapping and photos), rock samples and measurement while drilling (MWD) were used to describe the weakness zones that were encountered during tunneling. Rock samples were collected from two weakness zones and the general rock mass. These samples were tested in a point bearing machine for determination of their uniaxial compressive strength (UCS). These results indicated that the rock samples gathered from the weakness zones had significantly lower UCS than the samples from the rock mass. This was exceedingly clear for the samples of fault rock gathered in connection with a shear zone. The results from this work demonstrate that refraction seismicity had a high success rate for locating weakness zones, with the exception for the crossed narrow zones that were interpreted lacking a shear component. Empirical formulas relating Q-value and UCS with the seismic wave speed were used for calculating these factors for some interesting locations. The empirically calculated UCS was similar to the obtained UCS from the point bearing tests, while the empirically calculated Q-value showed large deviations from the mapped Q-value. The resistivity measurements ... |
format |
Bachelor Thesis |
author |
Renström, Viktor |
author_facet |
Renström, Viktor |
author_sort |
Renström, Viktor |
title |
The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen |
title_short |
The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen |
title_full |
The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen |
title_fullStr |
The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen |
title_full_unstemmed |
The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen |
title_sort |
influence of weakness zones on the tunnel stability based on investigations in bodøtunnelen |
publisher |
Luleå tekniska universitet, Geoteknologi |
publishDate |
2016 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59939 |
long_lat |
ENVELOPE(14.405,14.405,67.280,67.280) |
geographic |
Bodø Norway |
geographic_facet |
Bodø Norway |
genre |
Bodø Bodø Northern Norway |
genre_facet |
Bodø Bodø Northern Norway |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59939 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766379829017444352 |