GEOWEB® Load Support System

Project Name: Transmission Line and Electrical Substation Access Road

Project Location: Plaquemine, Louisiana

Project Challenge: Building a Stable, Unpaved Access Road

To support a new transmission line and electrical substation in an industrial area south of Plaquemine, Louisiana, a stable, unpaved access road was required. The project faced challenging wet soil conditions, including lean and fat clays interspersed with silt deposits extending to a depth of approximately 60 feet. Subgrade strength was highly variable, with California Bearing Ratio (CBR) values ranging from 0.5 to 1.5%.

This access road needed to support heavy construction equipment and ongoing maintenance traffic. The initial solution involved using geogrids with high-quality aggregate; however, due to the low subgrade strength, the geogrids could not withstand the heavy construction loads, necessitating an alternative approach.

Engineered Solution: GEOWEB Geocell Access Roads

Leveraging insights from past projects, the project engineer consulted with Presto Geosystems’ engineering team to develop a soil stabilization solution using the GEOWEB® Load Support System. Presto Geosystems provided a complimentary project evaluation to ensure the solution met all challenging site requirements. This system was chosen for its proven effectiveness in stabilizing unpaved roads over weak subgrades.

The recommended solution incorporated the GEOWEB System, a three-dimensional cellular structure designed to confine infill materials and control their shearing, lateral, and vertical movement. This system allows for the use of locally available, lower-quality, and cost-effective infill to construct roads and structures capable of withstanding very high loads. The GEOWEB System enhances the structural cohesion of the infill material, thereby increasing its effectiveness.

Installation Process: GEOWEB Load Support System

Installation began with removing the geogrid from the failed area, leveling the subgrade, and clearing away any vegetation and debris. A 4,800 lbs/ft enhanced woven geotextile was then placed on the prepared subgrade, providing separation, filtration, drainage, and additional reinforcement.

The GEOWEB GW30V6 (6-inch deep) panels were installed over the geotextile, with sections securely connected using ATRA® Keys at each interleaf and end-to-end connection. The GEOWEB cells were infilled with a mix of crushed aggregate and sand, which was overfilled and compacted to create a minimum two-inch wear surface, improving the road’s durability and longevity.

The access road project successfully utilized approximately 200,000 square feet of the GEOWEB Load Support System to construct a stable, unpaved access road over poor soil conditions. This solution ensured the road could support heavy construction vehicles and ongoing maintenance traffic while minimizing environmental impacts.

Benefits of the GEOWEB Load Support System

Installing the GEOWEB Load Support System offered numerous benefits, including improved load distribution, enhanced surface stability, minimized differential and consolidation settlement, and reduced maintenance requirements. This solution provided a sustainable and efficient way to support heavy construction equipment and ongoing maintenance traffic, aligning with the facility’s operational goals and long-term needs.