Trench Breakers

Thursday, January 24th, 2019 by Diane Burden

Challenge

Support a 300-metre stretch of natural gas pipeline that was being rehabilitated due to previous failure of the support system that was installed. The rehabilitation process required the pipeline to be constructed beneath a riverbed. Due to the nature of the project, TransCanada was unable to use the traditional method of trench breaking – sandbags.

Solution

Instead of supporting the pipeline with sandbags, a two-part, hydrophobic polyurethane was utilized to create TrenchBreakers, Support Pillows and Rock Guard. The material is a specially designed polyurethane engineered for this type of application. Installation of sandbags is very tedious, time-consuming and laborious, and can easily wash away or break down over time, unlike polyurethane.

Trench breakers were installed every 20' across the width of the exposed pipeline. In the deepest areas, the dimensions of the breakers were roughly 6' wide, 20’ across and 30’. Due to the hydrophobic qualities of the polyurethane, the application was perfect, considering the location and circumstances of the rehabilitation. The installation took significantly less time as compared to a sandbag install. The polyurethane does not wash away, at the same time preventing erosion on an incline or slope.

Polyurethane pillows were also installed between the breakers to support the pipeline. During this part of the installation, the surface of the pipe was also treated to protect it from damage and to keep the pipeline’s structural integrity intact. Polyurethane is also non-toxic and environmentally neutral, staving off damage to the surrounding ecosystem.