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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

The mesh model computed for the laser scanning data shown in Figures 7 and 8. It shows the mesh model produced using the scan data after blasting (a); after shotcrete layer has been applied (b); and a detailed view of the two cases (c).
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f9-sensors-12-11249: The mesh model computed for the laser scanning data shown in Figures 7 and 8. It shows the mesh model produced using the scan data after blasting (a); after shotcrete layer has been applied (b); and a detailed view of the two cases (c).

Mentions: Area and volume computations of the excavation material and shotcrete (sprayed concrete) are important for QA/QC purposes as well as for project accounting. As detailed in Section 4.3, this can be done, either directly on the point cloud data or using a 3D mesh model. Figure 8 shows an example of cross-section generation for computing over-breaks at the excavation face based on the raw point cloud data. For this purpose the typical cross-section is firstly overlaid on the raw (cleaned) scan data (Figure 8(a)). Then, a thin (<5 cm) slice of the point cloud (Figure 8(b)) is subtracted to construct a polyline that defines the excavated (actual) cross-section (Figure 8(c)). Thereby, the total over-break area (4.8 m2 or 4.14%) which corresponds to the chainage value of Figure 8(b) is computed by subtracting the typical cross-section area from the actual profile area. Cross-section information can also be produced employing a 3D mesh model. Figure 9 depicts the mesh model computed for the scan data shown in Figure 8.


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

Gikas V - Sensors (Basel) (2012)

The mesh model computed for the laser scanning data shown in Figures 7 and 8. It shows the mesh model produced using the scan data after blasting (a); after shotcrete layer has been applied (b); and a detailed view of the two cases (c).
© Copyright Policy
Related In: Results  -  Collection

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

f9-sensors-12-11249: The mesh model computed for the laser scanning data shown in Figures 7 and 8. It shows the mesh model produced using the scan data after blasting (a); after shotcrete layer has been applied (b); and a detailed view of the two cases (c).
Mentions: Area and volume computations of the excavation material and shotcrete (sprayed concrete) are important for QA/QC purposes as well as for project accounting. As detailed in Section 4.3, this can be done, either directly on the point cloud data or using a 3D mesh model. Figure 8 shows an example of cross-section generation for computing over-breaks at the excavation face based on the raw point cloud data. For this purpose the typical cross-section is firstly overlaid on the raw (cleaned) scan data (Figure 8(a)). Then, a thin (<5 cm) slice of the point cloud (Figure 8(b)) is subtracted to construct a polyline that defines the excavated (actual) cross-section (Figure 8(c)). Thereby, the total over-break area (4.8 m2 or 4.14%) which corresponds to the chainage value of Figure 8(b) is computed by subtracting the typical cross-section area from the actual profile area. Cross-section information can also be produced employing a 3D mesh model. Figure 9 depicts the mesh model computed for the scan data shown in Figure 8.

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