As part of the Virginia Department of Transportation’s (VDOT) work with the Virginia Department of Conservation and Recreation at Natural Bridge State Park in Rockbridge County, a geological analysis is being performed on the formation known as Natural Bridge, atop which runs Route 11.
VDOT engineers and geologists have begun planning a series of non-destructive geological tests to be completed this year. VDOT has contracted testing services through an agreement between the Virginia Transportation Research Council in Charlottesville and Radford University.
The testing will be led by Dr. Chester Watts of the Environmental and Engineering Geosciences Program at the Department of Geology at Radford University. Watts specializes in engineering geology and is a Certified Professional Geologist in the Commonwealth of Virginia.
The testing will comprise:
- Ground Penetrating Radar (GPR) providing 2D imaging of existing roadway layers;
- Terrestrial Light Detection and Ranging (LiDAR) providing 3-D representation of the geological formation’s surface features;
- Unmanned Aerial System Surveys for visual surface photographs and surface mapping,
- Electrical Resistivity measuring resistivity of the material at various depths provides, which is an indication of the material type (rock, sand, air) and water content. These data provide a 2-D image of the formation subsurface for use in later analyses;
- Seismic Reflection or Refraction to measure the density of rock and how sensitive the rock is to vibration; and
- Vibration monitoring, geophones, or other monitoring tools measuring ground movement, such as vibration from an external source.
The testing material will be reviewed by an advisory board whose members are independent of DCR and VDOT. At the conclusion of all testing an interim report will be produced by early 2018 with the final report in spring 2018.
More information on VDOT’s work with DCR for Natural Bridge can be found here: www.virginiadot.org/projects/staunton/rockbridge_county_8211_route_11_natural_bridge_state_park.asp