Waterview Connection Tunnels Auckland: TBM Design and Tunnelling Experiences

Quelle/credit: Herrenknecht

1 Cutting wheel assembly

Quelle/credit: Herrenknecht

2 The cutting wheel of the EPB Shield for the twin-tube tunnels of the Waterview Connection Project has a diameter of 14.46 m and was was tailored to the specific project conditions

Quelle/credit: Herrenknecht

3 Design of the secondary tunnel installation system, major features

Quelle/credit: Herrenknecht

4 Design of the secondary tunnel installation system, “drive through mode” and “culvert placing mode”

Quelle/credit: Herrenknecht

Quelle/credit: NZ Transport Agency

5 The EPB shield has an overall length of 87 m including backup gantries. The machine was ready to bore the first tunnel section on 31 October 2013

Quelle/credit: NZ Transport Agency

6 After breakthrough on 29 September 2014, the machine had to be turned around and pushed sidewise in the northern portal trench to start the excavation of the second bore in the opposite direction

Quelle/credit: NZ Transport Agency

The Waterview Connection Project represents one of the largest infrastructure developments in New Zealand. The project comprises twin-tube road tunnels that are built using a very large diameter tunnel boring machine (TBM). The tunnels impact a large number of existing buildings and utilities as they pass beneath residential property and public reserve. The tunnels also cross beneath the North Auckland Railway branch. Accordingly, exercising ground control to minimize settlements and adverse impacts to the community are of paramount importance. The tunnel project is built under high safety standards in an urban area and with shallow cover. The report addresses the TBM design and tunnelling aspects with experiences in large diameter TBM operation for the first of the twin-tube bores from the perspective of the machine manufacturer.

Introduction

For New Zealand’s largest road infrastructure project, the Waterview Connection in Auckland, one of the world’s largest TBMs successfully finished the excavation of the first of two tunnel tubes on September 29, 2014. Each bored tunnel has a length of about 2.4 km and an inner diameter of 13.1 m. Each will accommodate three lanes of traffic. The two tunnels are being excavated using one Earth Pressure Balance (EPB) Shield with a diameter of 14.41 m, customized to Auckland’s requirements and subsurface conditions.

Based on the project’s geotechnical risks and uncertainties with...