Chesapeake Bay Bridge Tunnel Expansion

Very challenging engineering project to construct a second tunnel, side-by-side with the existing one, without creating interruptions on road circulation of the current tunnel and access bridges.

Project Detail

D-wall trenches were executed to create the new access ramps to the new tunnel.

Client

Brasfond USA

Date

2016-2017

Estimate Budget

Industries

LOCATION

Norfolk, Virginia, USA

The two artificial islands were created in the 1950/60’s with backfill sand, characterized by its lack of cohesion, instability and high porosity. GEO provided permanent direct technical onsite assistance to support the client in all stages of the execution process.

The use of the G3® System allowed to assemble a small but optimized batching plant. Substantial environmental restrictions were referenced but GEO’s products prevented environmental issues since all are non-toxic and biodegradable. All employed products were scrutinized and fully approved by the main contractor (Dragados USA) and the project owner (CBBT).

Challenges

Relatively small Islands, characterized by the lack of space to lodge equipment and slurry tanks. These artificial islands are made of backfilled sea sand, having high porosity and lack of cohesion. Very difficult conditions for the use of any stabilization fluid.

The trench excavation should develop while maintaining the existing tunnel in operation (with live traffic) and having d-wall panels, in some cases, only 3.5ft (1m) away from the island wave breaker

Substantial environmental restrictions were referenced by the main contractor (Dragados USA) and the project owner (CBBT).

Solution

Our products and solutions, allowed to assemble a small but optimized batching plant. GEO’s products prevented environmental issues since all are non-toxic and biodegradable.

A combined application of G3® System products and stone filler was created. This combination of products allowed for an effective fluid loss control, minimizing slurry wastage and increase in product consumption. Being the natural filler an inert material that does not generate “cake”.

None of the completed D-wall panels presented overbreak values above 15% and the average was 7.4%. Proving an effective soil stabilization in these challenging soil conditions and in double panels reaching 14ft (4.27m) in length and up to 172yd3 (131.5m3) of concrete volume.

Key Figures

Scope:

D-wall panels with a total length of 1780ft (542.5m), having a thickness between 48 to 60 inches (1220 to 1525mm), and with a depth varying from 50 to 130ft (15 to 39.5m).

Achievements:

Controlled fluid loss. Average concrete Overbreak of 7.4%. Effective soil stabilization in double panels reaching 14ft (4.27m) in length and up to 172yd3 (131.5m3) of concrete volume. Panel excavations only 3.5ft (1m) away from the island wave breaker.

Geology:

The site soil profile is basically composed by backfilled sands. In the north Thimble Island, the Sands go from 0 to 120ft (36.5m); then a fine slightly sandy Silt with shells, from 120 to 158ft (36.5 to 48m).

Technologies Used

G3® System

The G3® Soil Stabilization System is a next-generation polymer technology designed to transform non-cohesive soils into stable, predictable environments for excavation and ground engineering. By forming a strong cross-linked network within the soil, the G3® system improves soil cohesion, minimizes fluid loss, and enhances operational efficiency, making it ideal for challenging soil conditions.

G Line

The G Line is a versatile polymer-based soil stabilization system used in geotechnical excavations to support soil structures. It is designed for use in various soil types and conditions, offering efficient mixing, rapid hydration, and compatibility with both fresh and salt water. The G Line components (GMud, GNet, G+) work together to enhance soil cohesion, reduce fluid loss, and promote particle suspension, making it ideal for applications in deep foundation projects.

XG Series

The XG Series, developed by GEO, is a range of innovative products based on a natural polymer for use in drilling and soil stabilization. Designed for high solubility and viscosity control, Cross-Gel XG serves as an efficient drilling fluid with long-lasting stability, effective sediment transport, and continuous reuse capability. The series includes complementary products—XG Break, XG Clean, and XG Shield—to optimize performance, manage fluid viscosity, and maintain polymer structure over extended operations.

Bentonite Suspension

A bentonite suspension system is a mixture of bentonite clay and water, forming a gel-like fluid that exhibits thixotropic properties, meaning it thickens when at rest and becomes more fluid when agitated. This suspension is used primarily in industries like construction, drilling, and geotechnical applications for its ability to provide stability and lubrication.

GelPro

GelPro is a highly soluble anionic polymer that forms a high-viscosity slurry when mixed with water. It hydrates quickly and requires minimal equipment for use, offering immediate application for soil stabilization. GelPro is ideal for stabilizing various geological formations, offering ease of hydration and consistent slurry formation. It can be mixed directly in the excavation or slurry batching plant without the need for pH adjustment or specialized mixers.

GMud Ultra

GMud Ultra is an anionic polymer that creates a high-viscosity slurry upon mixing with water. It hydrates quickly and requires no special equipment, offering fast application in less demanding soil profiles. Designed for use in less complex geological conditions, GMud Ultra simplifies soil stabilization with minimal equipment. For more difficult formations, additional G3 System products are recommended for enhanced performance.

PolyGel

PolyGel is an acrylic anionic polymer, available in dry granular form, known for its excellent hydration and solubility rates. It provides a balanced price-quality solution for soil stabilization. PolyGel is effective in soil stabilization and can be used in conjunction with other G3 System products to meet specific project requirements. It is also environmentally friendly, ensuring reliable results.

Fluid Loss Blockers

GEO’s fluid loss blocker system includes two products, GFiber and GBlock, designed to prevent fluid loss during soil stabilization. Fluid loss can compromise excavation stability, particularly in permeable or fractured soils. GFiber, made from natural mineral fibers, and GBlock, a fast-swelling synthetic polymer, create barriers in the soil to control seepage effectively. This system is compatible with support fluids such as the G3 System, Gline, XG series, Bentonite, and standalone slurries.

Micropile

Micropiles are small-diameter piles made from high-strength materials like carbon steel or ductile cast iron, driven into the ground to provide additional load-bearing capacity for structures. They are ideal for both new construction and foundation reinforcement in existing buildings, especially in areas with weak soil or limited access. Micropiles are often used where traditional foundation methods are impractical, offering a flexible, cost-effective solution with minimal disruption. Their installation requires minimal equipment, making them suitable for tight spaces or urban environments where heavy machinery is not feasible.

Bi-Directional Static Load Test

Bidirectional Static Load Testing (BDLT) is an advanced and efficient method for evaluating the load-bearing capacity of deep foundation piles and barrettes. This innovative testing technique is crucial for projects that require precise measurement of both skin friction and end bearing capacity in high-capacity foundations. The method involves performing full-scale static loading tests that evaluate the load performance of piles under axial compressive loads, which is essential for ensuring the stability and integrity of any foundation system.

Water / Wastewater Treatment

Our comprehensive array of specialized polymers is designed for water, wastewater, and sludge treatment, and all our products meet NSF certification, Halal certification, and applicable local certifications. We take on the challenges of water treatment across multiple sectors, including municipal, industrial, mining, agriculture, construction, civil engineering, and dredging, to ensure water is preserved and reused for the benefit of future generations.