Elevates’s consulting services were requested by Client to assist with the evaluation of a large drainage tunnel located in the subsurface at a site in Texas. The Client recently purchased the property and needed evaluation of this structure for insurance purposes. The tunnel is approximately 600 feet long and trends northward under a portion of a building located at the complex. The Client requested an initial imaging of the tunnel interior and the surface adjacent to the trend of the tunnel. Subsequent imaging of the tunnel interior will occur every two (2) years with a temporal analysis to determine changes in the structure.
Shown is the imagery data collected from the sUAS. This is an overall view of the site. The drainage tunnel entrance can be seen near the lower, right-hand portion of the image.
This is an image of the combined sUAS and terrestrial LiDAR model. Note that the sUAS surface LiDAR point cloud has been decimated to view “into the subsurface”. The terrestrial LiDAR data from the tunnel can be seen trending approximately through the middle of the site. Note the position of the tunnel under a building located in the bottom portion of the image.
Elevate used a combination of sUAS based LiDAR, ortho-photographic imaging and terrestrial LiDAR to accomplish the scope of work. The focus of the sUAS imaging was to serve as a record of current site conditions and provide spatial modeling of the site. Spatial data collected from the terrestrial LiDAR system was incorporated into the overall point cloud of the site using ground control points visible is all data sets. This allowed the tunnel point cloud to be placed accurately in the subsurface in relation to the surficial object of interest.
The high-resolution images and spatial model were transferred to the Client via digital file transfer for evaluation by their structural engineering team and insurance specialist. These will serve as baselines for future analysis of the site. Elevate also worked with the client to ensure that the data file formats were compatible with their engineers planned analysis software.
The use of multiple data collection methods linked by spatial control can provide more understand of a site than a single, or stand alone, model. As these features interact with one another in the real world it is beneficial to create models that allow them to interact and be evaluated together in digital space. this project also highlights the importance of communication between all project stakeholders when conducting spatial analysis projects as quality data that cannot be used by all parties is not valuable.
This image shows the full, combined model rotated so that the view is in cross-section. In this orientation, the tunnel can be “seen” in the subsurface below the building. This type of manipulation is one of the benefits of using multi-method spatial analysis and digital modeling.