Sacramento River East Levee Contract 4 – Construction of Seepage Cutoff Wall

he Sacramento River East Levee Contract 4 was the fourth contract of the American Common Features (ARCF) 2016 project. The United States Army Corps of Engineers (USACE) developed a program to improve the seepage and stability conditions along the Sacramento River East Levee (SREL). This contract included construction of a cutoff wall utilizing jet grouting or deep mixing method to adjoin to existing cutoff walls from previously completed contracts. TREVIICOS Corporation (TIC) was selected by the General Contractor, Maloney-Odin A Joint Venture (MOAJV) to be the Jet Grouting Contractor and complete the jet grout cutoff wall portion of the contract. The scope of work outlined for the Jet Grout contractor involved installation of a Jet Grout Cutoff Wall (JGCOW) connecting to previously installed Deep Mixing Method (DMM) Cutoff Walls. The project consisted of constructing a JGCOW at multiple locations with controlled strength and permeability properties. The project presented unique challenges for installing the cutoff wall, such as varying geology at each specific location, significant depths reaching up to 145+ feet, limited real estate near the active public and sensitive structures, active discharge pipes from a pump station, and an active pressurized gas line. To circumnavigate these unique challenges, as required by the contract specifications, TIC installed 8 foot or 10.5 foot diameter triple fluid jet grout columns utilizing air, water, and grout at high pressures. In addition to triple fluid, TIC also implemented some single fluid high pressure grout columns reaching diameters of 3 to 4 foot to mitigate unknown challenges that arose during the construction of the jet grout cutoff wall. This paper details the unique challenges encountered, and the solutions implemented to successfully install the jet grout cutoff wall.