Challenging installation of large diameter HDPE pipe by directional drilling provides a comprehensive water management solution and an improved environmental outcome

Abstract

This presentation describes the Chichester project and outlines the exceptional capability of the Australian PE pipe industry to deliver value to asset owners. After 85 years of operation, the pipe owner, Hunter Water, decided to replace the above ground 900mm metal pipe line that had been prone to flood damage and regularly required shutdowns for maintenance. The benefits of the project not only included improved water security for the community but also protection of the environment, in particular valuable wetland surrounds. The major job challenge involved finding an underground solution to replace the old pipe bridge across the river. The solution was of 1000mmSDR11 Polyethylene PE100 pipe installed under the river using Horizontal Direction Drilling (HDD). The Australian industry demonstrated capability to produce such a large PE100 pipe in such a large diameter and wall thickness. The 280m pipe string weighing 80 tonnes was joined on-site by butt welding 12 m sections. In the DDI stage of Chichester project the entire string was pulled through in a single process, meeting all performance expectations. The supply chain described in this project begins with a domestic supplier of quality PE100 pipe resin. Combined with the exceptional capability of the pipe manufacturer and welder, it became possible to offer the best solution to the project challenges. The PE100 pipe resin provided a unique package of performance attributes such as the capacity to manufacture pipes of very challenging sizes, produce high quality joints, withstand significant abuse during installation and end-use, capacity to join to steel pipe structure and ensure the structural integrity of the pipe network for long-term use.

Techniques