Caption title. At head of title: Project summary. Distributed to depository libraries in microfiche. "June 1987." "EPA/600-S2-87-023."

"The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement process is composed of separate bottom barrier and perimeter barrier construction processes. The bottom barrier construction is accomplished by propagating horizontal separations from a series of injection wells. A soil-bentonite slurry is pumped into these wells at low pressure, opening the separation and forming a barrier. In the process the ground is displaced upward by an amount corresponding to the thickness of the final barrier placed. The perimeter barrier is constructed by one of various means including slurry wall, jet grouting, or drill notch and blast. The perimeter barrier is constructed prior to the bottom if necessary to induce a favorable in-situ stress state. The technique was demonstrated at Whitehouse, FL where a block of earth 60 ft in diameter and 25 ft deep was lifted. Horizontal fractures were extended from seven injection holes to form the bottom barrier. The block was displaced upward as much as 12 in. by the injection of approximately 2,000 ft3 of bentonite slurry. Upward displacement was monitored by standard survey techniques during the lifting process. After displacement was completed, a topographic survey was conducted and the quality of the bottom barrier was assessed by core drilling."