Issuu

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Welcome – Sonya Leahy, Senior C&E Advisor, Mt Eden Station Team TBM Tunnelling Operations – Derek Whelan, TBM Construction Manager Management Plans – Jarrod Snowsill, Principal Planner Question time – Annabelle Wrigley, Mt Eden Station Team

Other staff present to answer questions Sam Tang ‐ Mined Tunnels Construction Caroline Secretin – Environmental Joe Grimes – Noise and Vibration Jane Matthews – Heritage Buildings George Brink ‐ Settlement Thibaut L'Hopital ‐ Mt Eden Station Project Manager Carmel Lapwood – Aotea Communications & Engagement team Simon Mitchell – Karangahape Communications & Engagement team

Traditionally, big machines like TBMs are named after a woman in honour of St Barbara, the patron saint and guardian of those working underground.

• 2 bored tunnels between Mount Eden Station and Aotea Station, and a fully grade separated junction within mined caverns connecting with two cut and cover tunnels to form east and west facing connections to the existing North Auckland Line. • Bored tunnels constructed using a 7.15m diameter TBM – about half the size used at Waterview. • TBM launches from Mt Eden. • Transfer through Karangahape • Breakout at Aotea • TBM disassembled and transported back to Mt Eden • Reassembled at Mt Eden and relaunched.

https://www.youtube.com/watch?v=1DrLQGxpj1Q 1:26 ‐ 2:12 min shows an overview of how the TBM operates.

• TBM arrives in October • Assemble for 3 months until January • While the TBM is being assembled mined tunnelling operations will be taking place at the Mt Eden site, will be approx. 50m in length • Mined sections at Mt Eden enable a more efficient TBM launch • 2 months of testing and commissioning in Mt Eden • TBM launch in April 2021 • 5 months to tunnel from Mt Eden to Karangahape • TBM is pushed through Karangahape Station • Further 3 months of tunnelling from Karangahape to Aotea • Once it arrives in Aotea we dismantle the TBM and transport it back to Mt Eden (approx. 3 months) • Start the second drive March 2022, 4 months to Mt Eden to Karangahape • 3 months from Karangahape to Aotea • Once it arrives at Aotea it gets disassembled again and taken off‐site

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TBM Diameter 7.15m TBM length 130m Earth Pressure Balance TBM 9 months of design and manufacture The cutting face has been designed specifically for our geology

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The tunnel is made up of 14,735 pre‐cast concrete segments 7 segments make up one ring 1.6m and 1.1m ring lengths These segments are built behind the TBM shield as it advances forward Rings are 300mm thick

• Conveyor eventually gets to 2km in total, including the full tunnel length from Aotea and out into the Mt Eden construction site

• The multi‐service vehicle will be used to transfer people in/out of the tunnel. It runs on the previously installed concrete rings. • The team transfer in/out of the TBM in shifts • All personal carry re‐breathers which is a device that can supply them up to 30 minutes of oxygen if required

• Earth Pressure Balance is balancing the ground ahead of the TBM against the soil in the excavation chamber. • The pressure maintained in area 2 (excavation chamber) is balanced against pressure of the surrounding soil, which minimises settlement

https://www.youtube.com/watch?v=1DrLQGxpj1Q 5:22 ‐ 7:32min shows the ring‐building operation

Overview of Tunnelling Construction Works between Aotea Station and Mt Eden Station (TBM Tunnel in green, Mined Tunnel in blue and Mined Tunnelling Cross Passages (xPx)) • At various points along the CRL route we will be constructing cross passages between tunnels for maintenance purposes. • At the Mt Eden end we will be constructing mined tunnels to assist the launch of the TBM. • The TBM will be pushed through the previously mined tunnels at Karangahape station. The TBM will not excavate through this area (shown in blue).

These slides show the Delivery Work Plans required under the environmental consents obtained by City Rail Link Limited (CRLL) for the project.

The draft CEMP and DWPs are provided to our CLGs for discussion. Following the CLG meeting, the CEMP/DWPs are amended, if necessary, to take onboard matters raised. They are then provided as a draft to Auckland Council before being submitted for Independent Peer Review (with independent subject matter experts). Following the IPR, the documents are submitted to Auckland Council for approval under the conditions of the project’s designation and certification under the conditions of our resource consents.

• The purpose of the CEMP is to confirm the details of CRL’s Tunnelling Construction Works and to set out how construction activities will be carried out and managed to avoid, remedy or mitigate adverse effects on the environment (including cumulative effects) as far as is reasonably practical, in accordance with the CRL designation and Aotea to North Auckland Line (A2N) resource consent conditions. • Our conditions also require preparation of a suite of sub‐plans ‐ Delivery Work Plans (DWPs) and Management Plans (MPs) – which set out detailed methods for avoiding, remedying or mitigating those potential adverse effects. Relevant sub‐plans for tunnelling deal with noise & vibration, built heritage and groundwater & settlement. • A summary of these plans was sent to CLG members with the invitation to this meeting. • The CEMP and sub‐plans are implemented throughout tunnelling construction and updated as necessary.

• A Construction Noise and Vibration Delivery Work Plan (CNV DWP) has been prepared to assess and mitigate any potential construction noise and vibration effects generated by the TBM operation and mined tunnelling works. • It also outlines procedures for managing any noise and vibration complaints, monitoring and reporting requirements and contingency measures in the event that noise or vibration limits are exceeded. • As the TBM and equipment for the mined tunnelling operate, vibration is transferred through the surrounding geology. Although this vibration dissipates as it travels through rock and soil, a reduced vibration level will transfer into surrounding building foundations. If this vibration is great enough, the floor and walls may imperceptibly vibrate, creating a low frequency rumble, known as groundborne noise. • All predicted vibration levels from mined tunnelling and TBM operations are below the building damage criteria and the TBM operation is not expected to exceed the vibration criteria. There may be some receivers where the project amenity vibration standards may be exceeded during TBM operation. • The tunnel is located between 8m and 35m below ground level. Based on the noise modelling, any exceedance of the amenity criteria is likely to be short lived and would occur when the TBM is at its closest approach to individual properties. • Site Specific Construction Noise and Vibration Management Plans have been prepared for notable/sensitive receivers. • The CNV DWP also outlines procedures for managing noise and vibration complaints,

monitoring and reporting requirements and contingency measures in the event that noise or vibration limits are exceeded.

• The HC DWP (Built Heritage) outlines the operational procedures that will be implemented to mitigate and manage effects on built heritage, including: • Building condition surveys to be undertaken prior to commencement of works • Groundwater and settlement monitoring • Vibration monitoring and management • Periodic monitoring to review Tunnelling Construction Works in proximity to built heritage. • Built heritage located above the path of the Tunnelling Construction Works includes scheduled buildings in the Upper Symonds Street Special Character Area and buildings in the Upper Symonds Street Historic Area. • A Historic Character Delivery Work Plan – Built Heritage Section has been prepared in accordance with designation conditions • Risks to built heritage during the Tunnelling Construction Works are due to the potential effects of vibration and ground settlement. Based on the CNV DWP, all predicted vibration levels from mined tunnelling and TBM operations are predicted to be below the building damage criteria.

• We've planned community information sessions with our tunnelling experts and management plan specialists to allow you to talk to them in person if you wish. However, we have had to postpone them due to Covid level 2.5 restrictions that limit gathering sizes. We will email you once new dates have been set.