Liquified Natural Gas (LNG) Site Preparation

In this site works and site development project, our client, a large engineering, procurement, and construction firm, self-performed the soil improvement at a $13 billion liquefaction facility and enlisted our assistance to complete the laydown area for soil and soil disposal. The construction laydown area served as storage for unsuitable and spoil materials from the adjacent facility. Ultimately, the design of the area controlled the displacement of weaker soils in the marsh and wildlife refuge located next to the facility.

Our team performed site preparation and constructed an access road and sheet pile barrier wall to extend the project site. Initially, the proposed scope of work included shallow soil mixing with quicklime and Portland cement. However, due to site conditions and the inability of the narrow soil-improved foundation to support the access road, the design was modified.

The revised design included the re-use of lime- and cement-stabilized spoils in combination with a multi-layered aggregate and geosynthetics to construct a 6-foot-thick access road. The completed access road provided a tide-resistant route for movement around the laydown area and a stable foundation for the installation of the proposed sheet pile perimeter wall.

Approximately 367,400 square feet of sheet pile were installed, covering over 7,800 linear feet using two Liebherr LRB23 pile driving rigs and a vibratory hammer mounted on a 120,000-pound hydraulic excavator to drive the sheets to final grade. Forgen worked closely with the client to accommodate as-built installation at the associated corners and along the revised alignment. All sheet pile work was installed from the elevated 26-foot-wide access road.

Additional site work included erosion and sediment controls, strict adherence to limits of disturbance, clearing and grubbing of the marsh area and associated trees, loadout of spoils for transportation to the site, unloading of sheet piles, site improvements within the sheet pile structure, and implementation of a stormwater pollution prevention plan. The project was delivered on schedule in November 2024.

The completed laydown area provided a stable and secure location for the storage of unsuitable and spoil materials, supporting ongoing operations at the liquefaction facility. The installation of over 367,400 square feet of sheet pile and the construction of more than 7,000 linear feet of barrier wall successfully contained the work zone and minimized environmental impacts on adjacent marshlands and the wildlife refuge. In-situ soil stabilization achieved the targeted 35 psi strength, improving ground performance and long-term stability. The access road and stormwater controls enhanced site functionality and compliance, enabling safe and efficient movement of materials and personnel.