Underwater Wick Drain Installation

Abstract: Pier G Wharf project added 246 feet of new wharf that included dredging, pile driving, backland improvements, a new rock dike, new shore power outlet, crane stops and new utility construction. The improved infrastructure will allow for higher capacity ships to berth, increasing the tenant, International Transportation Service (ITS), terminal's overall cargo movement.

Please describe the young professional’s contributions to the project, including but not limited to, building a model, writing a technical report, performing calculations, construction administration and observation tasks, and any aspects of design. (500 words max): My contributions to this project included verification of material quantity and work-in-place for monthly progress payments, reviewing contractor monthly schedule updates and 3-week look ahead schedules, daily review of RFIs, Submittals, Inspector Daily Reports, and on-site conflict resolution meetings. One unique contribution I made during construction was presenting on underwater wick drain installation to my division and writing an article for the engineering bureau newsletter. While many projects at the Port of Long Beach (POLB) have installed wick drains, this project was the first at the POLB to have underwater wick drains. I had the opportunity to go out on the barge, meet the subcontractor performing the work, and observe the process to share with my colleagues for future projects.
Wick drains are geotextile strips with channels that allow pore water to be expressed through soils that are required to consolidate faster. The first step in the installation process was the exploratory probing, in which a probing device is inserted below the mudline to capture the achievable depth before refusal. As-built drawings were provided by the contractor to show probe locations, depths, and any offsets required as a result of subsurface obstructions. Exploratory probing results indicated that there was leftover quarry run and an over-built rock dike subsurface. In order to get as close as possible to the wick drain design depth, the contractor was required to remove the quarry run rock. Wick drain installation works similarly to the exploratory probing. The wick drain is fed onto the mandrel of the crane and is connected to an anchor plate, which is then lowered to design depth and removed, leaving the wick drain behind. However, the over-built dike interfered with the installation of the wick drains. In working with geotechnical engineer, it was determined that wicks could be installed to the refusal depth and additional surcharge material would be placed in the affected area to expedite the consolidation process.
The Pier G Wharf Extension project went on to be successfully completed in March 2023. In the end, there was over 41,115 linear feet of wick drain installed on this project. I am fortunate to have learned so much while assigned to this project. I was able to collaborate with designers, contractors, terminal owners, and colleagues at the POLB to oversee the construction of the project and solve problems as they arose. The wick drain installation was a great opportunity for me to learn about a unique construction process and practice my writing and presentation skills.