Thesis - University Access Only
Master of Science (MS)
Department / School
The objective of this research was to examine the feasibility of an air injection grouting system for geothermal bores. The system that was researched used a pressurized blow tank to pneumatically transport dry bentonite granules through a three quarter inch hose into a wet bore. Upon contact with the annular fluid in the bore, water or drilling mud, the particles hydrated and formed a grout. A ball valve on the bottom of the tank allowed the feed rate of particles into the hose to be adjusted. Granular bentonites that were tested ranged in particle size from four to fifty mesh. The pneumatic conveying properties of granular bentonites were studied in dry injection tests. Mass flow rates up to 50 lb/min were found at a tank pressure of 25 psi through a fifty foot length of hose. Air flow rates ranged from 8 to 17 scfm for pressures of 15 to 25 psi. Tests simulating wet bore conditions were also performed. A method of removing the injection hose at a constant rate was found to produce a uniform, high solids content grout. A relationship between mass flow rate and the percent solids of the resulting grout was discovered in tests with drilling mud as an annular fluid. The mass flow rate and percent solids relationship for tests in water was influenced by the type of granular bentonite.
Library of Congress Subject Headings
Ground source heat pump systems
Grouting (Soil stabilization)
South Dakota State University
Streich, Galen A., "Design, Testing and Evaluation of an Air Injection Grouting System for Geothermal Bores" (1996). Electronic Theses and Dissertations. 249.