Rail-Supported Microtunneling
Location
Bay Park to Cedar Creek NY
Client
Western Bays Constructors
Oversight Engineer
John P. Picone
Project Date
September 2021
Summary
- Two (2) mile of 90" force main from Bay Park Sewage Treatment to the county owned Aqueduct under Sunrise Hwy using a tunnel boring machine.
- Rehab/Reline 7.3 mile stretch of abandoned aqueduct
- 1.6 miles of 90" force main from the aqueduct to the exisiting Cedar Creek water pollution control plant's outfall pipe using a tunnel boring machine.
- Multiple entry and exit shafts constructed throughout the project for the TBM launch and landing.
- Slurry was designed specifically to meet the demands of the formation encountered.
- A private rail spur was utilized to provide timely supplies and minimize transportation costs.
Overview
A 10.9-mile pipeline was developed to improve water quality for a city by redirecting treated water from a reclamation facility to a control plant for discharge through an existing ocean outfall. By utilizing microtunneling, crews could simultaneously work on multiple sections while minimizing disruption to surrounding communities.
What Made this complex
Since the formation was close to the bay and surrounding water sources, fluids had to be designed around two critical requirements:
- Preventing water exfiltration and infiltration
- Transporting a high concentration of solids back to the surface
Uncontrolled saltwater infiltration can significantly increase tunneling risk. Excessive water inflow can destabilize formations and even lead to situations where a machine becomes stuck in the bore.
How sentinel Solved it
With a specialized fluid program, bentonite and polymers were implemented to minimize viscosity while generating high yield points and gel strengths. However, due to the heavy sand formation, the project utilized hundreds of 2205 sacks of bentonite.
Supporting this large-scale supply, Sentinel’s Holtsville, New York, facility played a key role. Unlike many suppliers, Sentinel operates its own private rail spur, a rare logistical advantage in the region. This rail access allowed the team to efficiently receive and distribute large quantities of drilling fluid materials directly to the project site.
By utilizing the rail spur, Sentinel was able to deliver these material feedstocks in a timely and cost-effective manner, ensuring a consistent supply through critical project stages.
Throughout the entire project, the client completed all runs on time without a major saltwater intrusion due to Sentinel’s fluid program.
- All micro-tunneling boring machine (MTBM) drives were completed without the equipment becoming stuck
- Transportation costs were reduced by utilizing Sentinel’s private rail spur system
Videos
- Bay Park Conveyance - April 2022
