A new pipeline connection is to secure water supplies to a gas power plant in Port Arthur, Texas. Particular challenge: crossing under the Sabine-Neches Waterway, one of the busiest waterways in the US, and the adjacent hurricane protection dam.
Crossing sensitive infrastructure demands high safety standards. In the USA, the US Army Corps of Engineers (USACE) is responsible for developing such standards for the approx. 700 flood protection dams under its control and maintenance. Port Arthur also falls under the competence of USACE. In order to navigate precisely in the clayey soil and to avoid subsidence at the hurricane protection dam, the Direct Pipe® method is being used for the first time in Texas for under-crossing a dam controlled by USACE. Using this method, bridge foundations, levees and the Sabine-Neches Waterway are being crossed under with great accuracy. With top performances of 108 meters per day, the drilling team lays the pipeline extending 1,050 meters and with a diameter of 48 inches in a mere 22 days.
The combination of micro tunnelling and horizontal directional drilling permits swift and precise installation. This is based on inserting the product pipeline in a single work step. The Universal Navigation System developed by Herrenknecht allows for deviations of only a few centimeters, enabling inclines and curves to be driven with high accuracy along the alignment route. Under the watchful eye of the US Army Corps of Engineers, this technology has proven its worth even under difficult conditions with groundwater pressure of up to 4 bar and culminating in a successful project closing.