The development requires the installation of a 20-inch gas pipeline and a 4-inch service line across the shoreline in the Port Campbell National Park along the Great Ocean Road, one of the major tourist attractions in Australia. An account is given of the landfall site selection process, the collection of required site data, the identified geohazards, and the development of a unique construction method based on a combination of retractable micro-tunnelling and horizontal directional drilling, including an overview of the challenges that will be faced during construction.
These include the complex geotechnical conditions, the ever present high-energy Southern Ocean swell, and the environmental significance of the site. The design work performed demonstrates that trenchless technology can be applied with a relatively high degree of certainty of success, provided detailed attention is paid to a number of key design aspects. The paper focuses on these design aspects bearing in mind that horizontal directional drilling design guidelines are generally limited with respect to these challenging crossings.
