A Photogrammetric Method for Obtaining Soil Density
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS VICKSBURG United States
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There is a need for a simple, accurate soil density measurement system that does not require extensive calibration or significant health and safety measures for compaction quality control. This research describes the invention of a photogrammetric technique for obtaining the volume of an excavated hole in soil. This procedure requires a series of 8 to 16 digital photographs with a standard digital camera around the perimeter of an excavated hole with a reference scale in the scene. Algorithms convert the digital photographs into a colorized three-dimensional point cloud, which is automatically rotated into a plan view and displayed via the Matlab graphical user interface. Once the reference scale dimensions are input, the volume of the hole is calculated via a user selected ground plane. Once the mass of the excavated soil is input, the wet density of the soil is calculated by dividing by the volume of the hole. This procedure has been validated against both the nuclear density gauge and the sand cone apparatus and found to be equivalent in accuracy to both. This procedure enables soil density determination within 15 min with no replacement material, no specific excavated hole dimension, and no safety or health risks.
- Geology, Geochemistry and Mineralogy
- Cartography and Aerial Photography