42-in. Direct Pipe Through 227MPa Rock


42-in. Direct Pipe Through 227MPa Rock

Authors:

Kendall Matieshin, Innovative Pipeline Crossings Inc., Calgary, Alberta Canada
Peter Hennig, Innovative Pipeline Crossings Inc.

Abstract: This paper addresses the numerous challenges and learning experiences of the highly technical Direct Pipe Crossing of the Severn River, in Ontario, Canada. The crossing was a key component of TransCanada’s Gravenhurst Pipeline Replacement Project, a 1.6km NPS36 replacement line. The Severn River crossing was initially designed as a 312m 36” Direct Pipe crossing, as weak sand underneath the river risked the potential for a hydraulic fracture using Horizontal Directional Drilling methods.

To match the execution criteria’s, based on the provided geotechnical reports, a significant portion of the crossing was designed to drill through rock. For coating protection on the 36” product pipe, the decision was taken to install a 42” sacrificial pipe and pull back the product pipe from the exit side. This was the first time ever application of a product pipe pull back using Direct Pipe.

As the tunneling commenced, significantly harder rock was encountered. Further geotechnical testing was completed, confirming an average strength increase of 297% over what was anticipated. Other geological difference from the reports were also encountered throughout the tunnel. These geological differences caused technical challenges for the 42” Direct Pipe crossing. In spite of the numerous challenges occurred, the project was successfully executed and the final product pipe was installed within the client’s specification.

Publication Date: 2019

Presented at:
NASTT’s 2019 No-Dig Show Chicago, Illinois
March 17-21, 2019 | Paper Number: MA-T3-04


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