63rd Street Tunnel Brooklyn, New York Back to Project List     Jet Grouting Jet grouted columns provide crown support for large pipe jacking project, through glacial till deposits containing boulders and cobbles. Project Overview:   Layne GeoConstruction designed and constructed an array of jet grouted columns to stabilize a zone of unstable boulders and cobbles, containing little to no fine soils, and to mitigate collapses and sink holes which had been generated prior to the use of jet grouting. The work was performed from pavement grade, utilizing the single-fluid jet grouting method, to reduced impacts to a residential roadway. Jet grouting was performed along the alignment of the proposed 102-inch diameter sewer tunnel in advance of the pipe jacking operation. The column configuration consisted of a continuous block of jet grout columns for the full length of the pipe alignment. The columns were constructed outside the edges of the pipe to a depth of approximately 38 feet. The remainder of the columns within each row were terminated above the top of the pipe to facilitate the open face pipe jacking method that was employed.     Value of Work Performed: $350,000 Project Duration: 1 month Project Completion Date: May 2001 Project Reference: General Contractor E I C Associates Joseph Branco, President (973) 297-5230