Geotechnical Study and Foundation Structural Design, Next Generation Ionosonde (NEXION) Installation, Thule Air Base, Greenland
Abstract
This report presents the results of our geotechnical and structural design for the transmitter antenna of the Next Generation Ionosonde (NEXION) at Thule Air Base, Greenland, for the Space and Missile Systems Center, Remote Sensing Space Environmental Branch, and Air Force Weather. NEXION is a commercial-off-the-shelf ionospheric sounder used to measure the electron density of ionospheric plasma. The design required special considerations for installation, construction, and shipment due to the ice-rich permafrost soil conditions at Thule Air Base s remote and logistically difficult location. In particular, anchored tension ground connections could not withstand viscoelastic creep of ground ice under extreme wind-loading events. In addition, predicted future climate change required additional considerations to protect the thermal regime of the thaw-unstable sediments. Recommendations include excavation into permafrost soils, non-frost-susceptible structural replacement fill, and extruded polystyrene boardtype insulation to facilitate maintaining and improving the subsurface thermal regime and to provide favorable foundation performance for the NEXION tower system. Furthermore, given the remote site location and limited availability of on-site concreting capabilities, foundations require pre-casting and shipping via ocean transport vessel to Greenland. As such, we designed an alternative foundation detail, including anchor rods, to mitigate the potential for irreparable damage that may occur during shipping and transporting.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2015
- Accession Number
- ADA622109
Entities
People
- Kevin Bjella
Organizations
- Cold Regions Research and Engineering Laboratory