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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

Subset slice of the mesh model overlaid on the design shell for the Tempi T1 tunnel. The plot on the right shows the cross-section area differences obtained between nominal and measured profiles after excavation and after shotcrete layer has been applied respectively.
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f10-sensors-12-11249: Subset slice of the mesh model overlaid on the design shell for the Tempi T1 tunnel. The plot on the right shows the cross-section area differences obtained between nominal and measured profiles after excavation and after shotcrete layer has been applied respectively.

Mentions: As expected, the mesh model produced after a shotcrete layer has been applied (Figure 9(b)), is substantially smoother compared to the mesh model produced on unsupported ground (Figure 9(a)). Area and volume computations and their differences from the design values can be also produced using specialized software tools. As an example, Figure 10 shows a thin (1 m) slice of the mesh model of the excavated rock superposed upon the design shell. Moreover, Figure 10 presents the cross-section area computations obtained for an individual cycle length (i.e., the excavation progress (advancement) achieved during a cycle of operations). More specifically, it shows the area differences obtained between nominal (design) and measured cross-sections for the case of unsupported rock and after a shotcrete layer has been applied. Such plots help to compute over-break material as well as shotcrete volume and thickness as a function of tunnel chainage with profound benefits to the project owner and the contractor.


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

Gikas V - Sensors (Basel) (2012)

Subset slice of the mesh model overlaid on the design shell for the Tempi T1 tunnel. The plot on the right shows the cross-section area differences obtained between nominal and measured profiles after excavation and after shotcrete layer has been applied respectively.
© Copyright Policy
Related In: Results  -  Collection

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

f10-sensors-12-11249: Subset slice of the mesh model overlaid on the design shell for the Tempi T1 tunnel. The plot on the right shows the cross-section area differences obtained between nominal and measured profiles after excavation and after shotcrete layer has been applied respectively.
Mentions: As expected, the mesh model produced after a shotcrete layer has been applied (Figure 9(b)), is substantially smoother compared to the mesh model produced on unsupported ground (Figure 9(a)). Area and volume computations and their differences from the design values can be also produced using specialized software tools. As an example, Figure 10 shows a thin (1 m) slice of the mesh model of the excavated rock superposed upon the design shell. Moreover, Figure 10 presents the cross-section area computations obtained for an individual cycle length (i.e., the excavation progress (advancement) achieved during a cycle of operations). More specifically, it shows the area differences obtained between nominal (design) and measured cross-sections for the case of unsupported rock and after a shotcrete layer has been applied. Such plots help to compute over-break material as well as shotcrete volume and thickness as a function of tunnel chainage with profound benefits to the project owner and the contractor.

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