Salt Creek Gravity Sewer Interceptor Chula Vista, California Back to Project List Jet Grouting Battered, double-fluid jet grout columns are installed at a 20-inch inclination from vertical to underpin a critical existing 72-inch-diameter sewer line. Project Overview: Layne GeoConstruction designed and constructed an array of single-fluid and double-fluid jet grout columns to underpin and provide temporary support of an active 72-inch-diameter sewer line. A total of 120 jet grout columns of 3 to 5 feet in diameter were installed to depths of 15 to 20 feet, achieving compressive strengths of 500 to 1500 psi. The jet grouting also provided temporary groundwater control, allowing the new micro-tunnel and juncture structure to be incorporated into the live sewer. The jet grouting was performed near several existing, critical utilities, and within the side slope of an off-ramp along Interstate Highway Route I-5. The jet grouting work was successfully performed with no movement of the existing sewer recorded.     Value of Work Performed: $225,000 Project Duration: 1 month Project Completion Date: June 2003 Project Reference: Project Owner: City of Chula Vista, California Kirk P. Ammerman (619) 691-5021 General Contractor: Modem Continental Construction Co., Inc. Joseph Clougherty (617) 864-6300