GeoEngineers is pleased to announce the successful completion of the first Direct Pipe® crossing of a US Army Corps of Engineers (USACE)-regulated levee. The 48-inch-diameter pipeline stretches for more than a half-mile crossing under the Sabine Neches Waterway and the levee and railroad tracks in Port Arthur, Texas. It will bring water from Port Arthur to Cheniere Energy’s LNG facility in Louisiana.
GeoEngineers’ services for the project included geotechnical and trenchless engineering along with construction observation. Principal Jon Robison, PE led the engineering design and construction observation services for the milestone project, and other GeoEngineers team members included Principal and Trenchless Energy Group Leader Mark Miller, PE; Senior Geotechnical Engineer Drew Sparks, PE; Staff Engineers Nicholas Arens and Sarkar Sayem; and CAD Designers Ben Lane and Blake Martin. The successful installation of the pipeline is due to the great work of the entire project team, which included: prime civil engineer Arceneaux, Wilson & Cole, contractors Strike and Laney Directional Drilling Company, and Direct Pipe equipment manufacturer Herrenknecht AG.
The use of Direct Pipe technology was necessary due to the need for maintaining low fluid pressures in the soil formations during installation. These pressures, which were not obtainable using a horizontal directional drilling (HDD) method, must be kept low because hydraulic fracture of soil during construction can lead to degradation of the foundation soil beneath the levee. This in turn can cause ground surface settlement, bearing capacity failure, undesired seepage flow path creation, and other undesirable or even disastrous consequences. To design and obtain agency permission for the Direct Pipe crossing, GeoEngineers used its previously-developed Direct Pipe design methodology and program to develop a new engineering pressure model and pressure monitoring methodology for levees and other pressure-sensitive areas. GeoEngineers worked closely with Arceneaux, Wilson & Cole and the USACE to obtain approvals for this innovation. Construction operations took 22 days after launching the microtunnel boring machine, and ended successfully with no significant pressure exceedances or delays.