South Boston Piers Transitway – Silver Line Russia Wharf & Fort Point Channel Tunnel MBTA Contract E02CN15 Boston, Massachusetts Back to Project List Jet Grouting Double fluid jet grouted columns stabilize deep excavation base, and act as a subsurface strut for cut and cover tunnel. Project Overview: Layne GeoConstruction designed and constructed a system of secant and tangent jet grouted columns to stabilize and seal the base of a sheet pile cofferdam. The jet grouting also acted as a subsurface strut, by providing toe support for the sheet pile system. Additionally, jet grouted columns improved weak soils and provided foundation support for the setting of immersed tube tunnel segments directly adjacent to the cofferdam. The jet grouting was utilized in lieu of the contract design that specified deep soil mixing. The work was successfully completed in Boston Blue Clay, and yielded mixed in place soilcrete average strengths of 800 psi. Jet grouting was performed to depths of over 105 feet with a single stroke drill rig.     Value of Work Performed: $1,000,000 Project Duration: 3 month Project Completion Date: December 2000 Project Reference: Owner Mass. Bay Transportation Authority Geotechnical Engineer of Record David Shields, GEI (781) 721-4032