In Situ Stabilization of Geologic Materials by Vitrification using Plasma Arc Technology

Period of Performance: 08/26/1997 - 02/26/1998


Phase 1 STTR

Recipient Firm

Plasma Processing Enterprises
PO Box 99088
Raleigh, NC 27624
Principal Investigator
Firm POC

Research Institution

Georgia Institute of Technology
225 North Ave NW
Atlanta, GA 30332
Institution POC


The subterranean application of plasma arc technology would result in the in situ transformation of virtually any geologic material into a vitrified rock-like mass (similar to obsidian), that is durable, strong, and highly resistant to leaching. Conceptually, a plasma arc torch would be lowered into a borehole to any depth and operated at progressively higher levels to thermally convert a mass of soil into a vertical column of vitrified and stabilized material up to 10 feet in diameter. This process of plasma stabilization of geologic materials is expected to be rapid, efficient, cost-effective, and simple. By applying this technique over a systematic grid pattern, the process would become a viable means of stabilizing weak foundation materials and unstable slopes, creating pile structures or coalescing the columns into a large contiguous monolith. The objectives of the Phase I program would be to conduct laboratory-scale experiments in selected rock and weathered rock materials at the 100kW and 200kW plasma torch power levels. the improvement in the engineering properties of the vitrified and adjacent heat-treated rock materials will be determined. In addition, the mechanical interrelationship between the vitrified mass and the surrounding undisturbed materials will be evaluated. Based on these data and the estimated unit costs to stabilize the geologic materials, the commercialization potential of the various ground improvement applications will be assessed. In situ plasma stabilization technology offers the potential to rapidly and cost-effectively improve any geologic foundation materials tha cannot be economically stabilized with current technologies. Poor foundation conditions which may be especially well suited to rapid liquefaction from earthquakes; man-made waste deposits (landfills, sludge beds, dredged materials, mine-tailings); unstable slopes and landslides; and structures undergoing excessive settlement. If this technology is brought to its full technological potential, fundamental improvements in the field of foundation engineering would be possible. foundation conditions would no longer be a limiting factor in construction operations.