1. Data collection using drones, LiDAR scanners and field ...
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Nykirke-Barkåker is one of the railway sections where a double-track high-speed line is being built on the Vestfold line (south west of Oslo). To make room for a new double-track, a rock slope close to the existing track must be adjusted or removed by blasting. Prior to blasting, NGI in collaboration with Geovita was responsible for creating a 3D rock model of the slope, including visualization of the cracks and assessment of risk associated with blasting. Stability assessment and mapping of cracks Before blasting the rock slope, a stability assessment is necessary. This involves identifying the fractures and cracks in the rock mass, which in turn helps to identify potential unstable rock blocks, and thus assess the stability of the slope. NGI and Geovita have used a comprehensive digital work,ow to solve this task, with an increasing degree of R&D during the project. The work mainly consisted of the following steps: 1. Data collection using drones, LiDAR scanners and field measurements Project | 3D modelling of rock slope PERIOD | 2020 - 2020 COUNTRY | MARKET | GEOTECHNICS AND ENVIRONMENT PROJECT MANAGER | TOM FRODE HANSEN PARTNER | GEOVITA AS
Transcript of 1. Data collection using drones, LiDAR scanners and field ...
Nykirke-Barkåker is one of the railway sections where a double-track high-speed line is beingbuilt on the Vestfold line (south west of Oslo). To make room for a new double-track, a rockslope close to the existing track must be adjusted or removed by blasting. Prior to blasting,NGI in collaboration with Geovita was responsible for creating a 3D rock model of the slope,including visualization of the cracks and assessment of risk associated with blasting.
Stability assessment and mapping of cracksBefore blasting the rock slope, a stability assessment is necessary. This involves identifying thefractures and cracks in the rock mass, which in turn helps to identify potential unstable rockblocks, and thus assess the stability of the slope.
NGI and Geovita have used a comprehensive digital work ow to solve this task, with anincreasing degree of R&D during the project. The work mainly consisted of the followingsteps:
1. Data collection using drones, LiDAR scanners and field measurements
Project | 3D modelling of rock slope
PERIOD | 2020 - 2020
COUNTRY |
MARKET | GEOTECHNICS AND
ENVIRONMENT
PROJECT MANAGER | TOM FRODE
HANSEN
PARTNER | GEOVITA AS
2. Processing and processing of point cloud (collected data) using software (CloudCompare and Maptek Pointstudio)
3. Crack detection on 3D model in Maptek
4. Visualize cracks and potentially unstable blocks in Rhino3D / Grasshopper
Data collection and 3D modellingTo produce a complete point cloud over the entire slope, both photogrammetry (drone) andLiDAR scanning were used. Lots of vegetation and an existing safety net made it challengingto get a complete point cloud only with the help of a drone. Complemented by LiDAR scanningand manual ltration of vegetation, the resulting point cloud became better suited for furthertreatment. Field measurements of the fracture orientation were also performed in order beable to verify the quality of the fracture classi cation at a later stage.
Before the point cloud could be transformed into a 3D model, it was processed using theCloudCompare and Maptek Pointstudio software. Here, ltering of point density and noisewas performed, and unnecessary parts of the point cloud were removed, for exampleoverlapping parts from the two data collection methods.
The point cloud was then transformed into a mesh, and then assembled into a 3D model. Then,a semi-automatic crack detection was performed using Pointstudio, where similar cracks weregrouped into crack sets. A kinematic analysis was performed in Pointstudio, and the risk-exposed cracks were identi ed.
The cracks were imported into the software Rhino3D / Grasshopper, where one could identifypotential unstable blocks using the 3D model and the crack sets, and calculate the volume andweight of the blocks.
3D rock model and crack recognition of the rock slope
Information ow and improved understandingFrom ongoing research at NGI, work is being done to develop a comprehensive automaticwork ow, which will facilitate the task of transforming collected eld data into a 3Dvisualization and end up with a recommendation of necessary bolt force and design to secureindividual blocks. This will also contribute to a simpler ow of information and an improvedunderstanding for all parties involved in the securing process for construction in rock.
Arnstein AarsetPosition | Head of SectionRock EngineeringE | [email protected] | +47 976 00 103
Jessica Ka Yi ChiuPosition | Project adviser IRock EngineeringE | [email protected] | +47 968 77 853
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