Development of a Geotechnical GIS for Subsurface Characterization with Three Dimensional Modeling Capabilities

摘要

The New Hampshire Department of Transportation initiated this research to develop a geographical information system (GIS) that visualizes subsurface conditions three dimensionally by pulling together geotechnical data containing spatial references. It incorporates several geotechnical projects ranging in size from a fairly small roadway project to a much larger roadway by-pass project. The research procedure encompassed taking subsurface data housed on one of the Departments computer servers and exporting the data as text delimited files into a GIS running a 3D modeling extension. A statewide GIS layer was created to access all the available subsurface data so existing data in close proximity to new projects could easily be recognized. The GIS utilizes the data to observe the existing subsurface conditions three dimensionally. By observing where the least confident data was located, the 3D modeling extension helped to determine where and how many additional explorations were needed to adequately map the subsurface conditions to a defined level of confidence. For each project, soil and bedrock surfaces were identified and the bedrock surface was exported into a CAD system where project cross sections were drawn depicting the bedrock depths along the new roadway centerline. The results of the research indicated that a GIS containing existing subsurface data running a 3D modeling extension could adequately map bedrock surface elevations with a minimal amount of additional subsurface explorations. It also demonstrates how new and existing soil density and bedrock surface elevation data can easily be observed three dimensionally on a computer screen.