Superjet Grouting and the Quality of Its Product: Fid-Bau Portal

Superjet Grouting and the Quality of Its Product

Burke, G. K. / Peterson, J. H. / Smith, M. L.

SuperJet Grouting was performed for the first time in North America to create an in situ wale and strut system at the base of a cut-and-cover tunnel, part of the Atlantic City Expressway Extension. The application of any new technology creates an enhanced need for verification and control. The fast track nature of this design-construct opportunity meant that there was little room for error, particularly so since the use of SuperJet grouting was predicated on cost and schedule savings. SuperJet grouting is a form of jet grouting that permits the construction of exceptionally large soilcrete columns, up to 5 m (16 ft) in diameter. Compared to standard jet grouting, this represents a 400 percent increase in column size. Furthermore, this increase is achieved without any decrease in product quality. The SuperJet system does this by mechanically and hydraulically focusing the injection of the cementitious grout for pinpoint cutting and erosion of very large volumes of soil in situ. The excess soil-grout mixture is simultaneously expelled at the surface, preventing pressurization and hydrofracture and leaving a high-cement-content, soil-grout mixture in situ to solidify. SuperJet grouting, as applied on the Brigantine-Atlantic City Connector project, realized a substantial decrease in time and cost while providing a product of exceptional quality. This paper describes the system and its utilization on the project, with focus on the quality aspects of the product in situ. All methods of sampling and testing are described and the results of testing are summarized.