Jet Grouting Improvement at Pier D, Port of Long Beach

Being one of America's premier seaports, the Port of Long Beach has embarked on an ambitious $1.2 billion Middle Harbor Development Program that involves expansion and modernization of two existing container terminals at Pier E and Pier F. As part of Phase 1, Stage 1 of the program, Pier D, which defines the western edge of the development, will be cut back to expand the Slip 3 channel to accommodate navigation of larger vessels. Active oil wells within the Pier D backland need to be protected and operational during construction. The subsurface materials consist of an old buried rock dike that subsided due to oil extraction activities. In order to achieve the maximum width of the Slip 3 channel while constrained by the presence of active oil wells in the backland, the Pier D cut had to be inclined at 1.6H:1V (horizontal : vertical) which is much steeper than typical submerged slope cuts. The steeper slope cut required a new secant pile wall as well as some form of ground improvement to soils below the rock dike and in areas outside the rock dike prior to dredging to ensure stability of the slope and to protect backland facilities. Due to the presence of the buried rock dike, jet grouting was chosen as the most practical and cost-effective option among the various available ground improvement techniques. This paper discusses the geotechnical investigation and site characterization associated with the design of the jet grouting improvement. This paper also presents the controlling jet grouting parameters developed from the test sections prior to production, the quality control monitoring, and the challenges faced during construction and how they were addressed to successfully complete construction of jet grout columns.