Event created by Jackson Jones
TWf webinar
The City of Gold Coast required an upgrade of the existing recycled water release system at the Southport Seaway, to accommodate continuing population growth. The project solution included a pipe capable of transferring 6,300 l/s of recycled water from the mainland across the Broadwater seaway via a marine pipeline to an outfall located off South Stradbroke Island.
In order to protect the waterways from environmental impacts, an alternative construction method to the original dredged pipeline plan was proposed by the builder John Holland and their specialist subcontractor Bothar Boring and Tunnelling Australia (Bothar). This alternative adopted trenchless construction using micro tunnelling (MTBM) methods.
The project involved the tunnelling of two separate drives, the first being a 1385 m length of bored tunnel beneath the Broadwater Seaway between Quota Park on the mainland and South Stradbroke Island. It included the construction of two deep shafts and a 2.5 m (OD) reinforced concrete carrier pipe that was installed with pipe jacking techniques.
The second drive involved a trenchless 617m crossing between Quota Park and O’Connell Park, including a section beneath Biggera Creek that was constructed using pipe jacking and micro tunnelling using a 1.940 m (OD) glass-reinforced plastic (GRP) pipe. Golder was engaged by Bothar to join the project team and provide temporary works design support, design services for the tunneling works, construction support that included site attendance across both drives.
This presentation will discuss some of the challenges from the designer’s perspective.
Speaker
Trevor O’Shannessy, Golder, Principal Geotechnical Engineer
Trevor has over 20 years of experience in civil, mining and water industries. He has extensive experience in geotechnical investigation, design and contractor supervision. He has led complex geotechnical and geophysical investigations for many tunnelling projects, including the initial Hobsons Bay Crossing Study, the Melbourne Main Sewer Replacement Project and for development of the Westgate Tunnel Concept Design. Trevor has been leading design teams for multiple trenchless construction projects across Australia.