ASTT Webinar Number 10.

The ASTT is thrilled to be able to continue on with its webinars in 2021 and once again provide this FREE webinar in lieu of our popular trenchless forums which are presently suspended due to the Coronavirus restrictions.

The webinar will be a presentation by Stuart Anderson, Project Manager from McConnell Dowell in New Zealand. The webinar is entitled " Trenchless Outfall Successful Sub-Sea mTBM Recoveries” and will be held on Friday 23 July commencing at 1:00pm (Eastern Standard Time) and concluding at 2:00pm

Abstract of Presentation
Stuart Anderson will describe the methodologies used in the construction of pipeline shore crossings, outfalls and intakes has varied significantly over the last century, with the approaches over the last decade becoming more and more tightly regulated around environmentally sustainable outcomes.  The wide excavated cuttings through beach dunes and dredged, or even blasted, trenches in the sea-bed are essentially relegated to the annals of history in most countries.  The use of techniques that do not heavily impact the sensitive and fragile coastline, dunes, beaches, foreshores and surf zones, or their endemic fauna and flora, are now mandated in Australasia and this has driven a very positive trend towards utilising trenchless technology.

With the tightening environmental regulations around prevention of hydro frac-out or mud loss into the environment, the requirement for larger diameter pipelines / intakes / outfalls, and a trend for much longer distances offshore and into much more extreme marine conditions, the requirement to use microtunnelling or pipe jacking mini TBM’s is becoming more commonplace where HDD techniques may not be feasible.  At the end of the tunnelling drive, the mTBM must be retrieved vertically from below or at the sea floor and returned to land, or otherwise ‘sacrificed’ with shield body left in place below the sea floor.  Wherever economically feasible, the mTBM will be retrieved.

In Australasia, 10 offshore marine TBM recoveries have been completed to date, with 7 of these by McConnell Dowell, commencing with the Tahuna Ocean Outfall in Dunedin in 2008, and the most recent off NZ’s South Island West Coast at Hokitika in 2021. This presentation aims to introduce the audience to mTBM marine recoveries:

• What type of Projects warrant a mTBM Marine Recovery;
• History of mTBM Marine Recoveries in Southern Hemisphere;

Through providing an overview of mTBM retrievals completed by McConnell Dowell, Stuart will explain:

• Benefits of a Marine Recovery over setting up an offshore worksite (cost, time, safety, environmental impact);
• Alternative approaches to the daylighting of TBM for retrieval – drive into pre-excavated trench or uncover via post-excavated trench;
• Methods for lifting out the TBM – Crane (Jetty or Shore), Crane or Jack-Up Barge, Airbags, Recovery Pontoon;
• Returning the TBM to shore.

You are invited to a Zoom webinar. Click on the link under to join this webinar:

https://us02web.zoom.us/j/83278743576?pwd=V0hQekNON2c1OUw0VkZQVUlZUkUvdz09

If you experience difficulties in joining this free event, then please email Jeff Pace, ASTT Secretary on secretary@astt.com.au for assistance.
As an online attendee, you will be able to attend the webinar from anywhere and will be able to submit questions that will be answered at the end of the presentation.

We from the ASTT hope you can join us on 23 July 2021.

Jeff Pace
ASTT Secretary