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Three-dimensional laser scanning for geometry documentation and construction management of highway tunnels during excavation.

Gikas V - Sensors (Basel) (2012)

Bottom Line: This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels.Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction.Specific case studies are considered based on two construction sites in Greece.

View Article: PubMed Central - PubMed

Affiliation: School of Rural and Surveying Engineering, National Technical University of Athens, 9 I Polytechniou Str., Zographou, Athens 15780, Greece. vgikas@central.ntua.gr

ABSTRACT
Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered.

No MeSH data available.


Related in: MedlinePlus

TLS setup during data acquisition. Depending on positional accuracy requirements four targets were used for geo-referencing the point cloud.
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f6-sensors-12-11249: TLS setup during data acquisition. Depending on positional accuracy requirements four targets were used for geo-referencing the point cloud.

Mentions: The laser scanning method has been adopted at Tempi T1 construction site for the purpose of documentation of the tunnel geometry and for geology characterization. This section provides several practical examples on the use of TLS technology for tunnel face documentation at two stages following the beginning of the excavation cycle; firstly, immediately after blasting and removal of the excavation material, and secondly, after a shotcrete layer has been applied [39]. Figure 6 shows the observation setup of the scanner and the sphere targets used for data geo-referencing. To ensure safe operation conditions and the best possible observation geometry, the scanner was setup approximately 10 m behind the tunnel face and within the limit of supported ground. Prior to the scan process the location of the TLS and the targets was computed by means of a total station. During data collection, the scanner recognizes automatically the targets in the point cloud, applies some fine scanning techniques and produces relative coordinates which are used for point cloud alignment of subsequent scans. In order to allow detailed mapping of the geologic conditions at the excavation face the angular spacing was defined equal to 0.001 radian increment. Also, digital images were captured at the same time with no need of additional lighting.


Three-dimensional laser scanning for geometry documentation and construction management of highway tunnels during excavation.

Gikas V - Sensors (Basel) (2012)

TLS setup during data acquisition. Depending on positional accuracy requirements four targets were used for geo-referencing the point cloud.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472883&req=5

f6-sensors-12-11249: TLS setup during data acquisition. Depending on positional accuracy requirements four targets were used for geo-referencing the point cloud.
Mentions: The laser scanning method has been adopted at Tempi T1 construction site for the purpose of documentation of the tunnel geometry and for geology characterization. This section provides several practical examples on the use of TLS technology for tunnel face documentation at two stages following the beginning of the excavation cycle; firstly, immediately after blasting and removal of the excavation material, and secondly, after a shotcrete layer has been applied [39]. Figure 6 shows the observation setup of the scanner and the sphere targets used for data geo-referencing. To ensure safe operation conditions and the best possible observation geometry, the scanner was setup approximately 10 m behind the tunnel face and within the limit of supported ground. Prior to the scan process the location of the TLS and the targets was computed by means of a total station. During data collection, the scanner recognizes automatically the targets in the point cloud, applies some fine scanning techniques and produces relative coordinates which are used for point cloud alignment of subsequent scans. In order to allow detailed mapping of the geologic conditions at the excavation face the angular spacing was defined equal to 0.001 radian increment. Also, digital images were captured at the same time with no need of additional lighting.

Bottom Line: This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels.Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction.Specific case studies are considered based on two construction sites in Greece.

View Article: PubMed Central - PubMed

Affiliation: School of Rural and Surveying Engineering, National Technical University of Athens, 9 I Polytechniou Str., Zographou, Athens 15780, Greece. vgikas@central.ntua.gr

ABSTRACT
Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered.

No MeSH data available.


Related in: MedlinePlus