2019 SA-NT Symposium

Tunnelling under Adelaide

Michael R. King and Dr Oskar Sigl

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The South Australian-Northern Territories Chapter of the Australian Geomechanics Society (AGS) and the Australian Tunnelling Society (ATS) are pleased to announce the 2019 AGS Symposium titled “Tunnelling under Adelaide” which is to be held on Monday 28th October 2019.

The symposium forms part of the continuing programme of events organised by the SA-NT Chapter of the AGS and aims to provide the engineering profession with a comprehensive introduction to the geotechnical aspects of tunnelling in soil in urban areas, including best practice techniques and recent developments.

Overview of the 2019 Symposium

South Australia has seen significant investment in transport infrastructure in recent years. The development of a dedicated non- stop North-South Corridor for Adelaide is a direct result of a strategic objective to reduce Adelaide’s urban road congestion. The North-South Corridor is one of Adelaide’s most important transport corridors and
is the major route for north and south bound traffic including freight vehicles running between Gawler and Old Noarlunga, a distance
of some 78 km. Many of the associated projects involve complex geotechnical challenges.

The South Australian Government is currently considering the viability of tunnelling options for the remaining sections of the strategic North-South Corridor between River Torrens and Darlington. Design and construction of the remaining sections will be the biggest single infrastructure project in South Australia’s history.

This symposium will present overviews of current design practice, state of-the-art practices, novel technologies and innovative solutions, and case studies demonstrating applications of advanced techniques and cost-effective solutions in the design and construction of TBM tunnels in clay, with a focus on the geotechnical challenges associated with the completion of the North-South Corridor between the River Torrens and Darlington. The symposium will bring together professional engineers, researchers, specialist contractors, regulators, educators and students to share and discuss their experiences on the topic of the design and construction of TBM tunnels and their associated challenges and opportunities.

Topics

Planning and Investigation

Procurement models
Risk management
The role of ground investigation and Geotechnical Baseline Reports
Ground conditions in Adelaide including geotechnical and hydrogeological hazards

Geotechnical Design

Management of ground movements impacts on existing infrastructure
Groundwater control in high risk urban environments
Instrumentation and monitoring
Ground treatment

Excavation and Construction Methods

Large diameter TBM selection, design and performance
Sprayed concrete lining and membrane construction
Cross passage construction
Crossover structures
Waterproofing of cross passages, shafts and caverns
The role of tunnel engineers during construction and the use of the observational method

Case histories

TBM tunnelling projects in Adelaide, London and Auckland will be presented

Sponsorship Opportunities

Information on sponsorship opportunities.

Call for abstracts

Information on abstract submissions.

About the speakers

Michael R. King Director, MK Tunnelling Limited

“Crossrail tunnelling in the London Clay formation”

Michael King is an independent consultant who has been involved in tunnelling projects for over 35 years, including segmentally lined tunnels, sprayed concrete linings and diaphragm wall and piled structures. He has worked directly for both contracting and consulting organisations and has also been seconded into Client organisations on major projects. His international project involvement includes the Channel Tunnel (UK/France), the Arrowhead water project (USA), Lisbon Metro (Portugal), Los Angeles Metro (USA), Sao Paulo Metro (Brazil) and the Jubilee Line Extension (UK). Mike has also been involved in Expert Witness cases and recently completed 7 years as Head of Underground Construction on the Crossrail project. In 2019 Mike was awarded the James Clark Medal for his contributions to, and achievements in tunnelling by the British Tunnelling Society.

The Crossrail project in London (UK) spent 7 years excavating and lining tunnels and shafts within the London Basin. Construction activities encountered and dealt with a range of geological strata, including recent deposits of Made Ground, Alluvium and River Terrace Gravels, over-consolidated London clay, variable mixed sediments of sands gravels and clays, uniform and fine-grained sands, and the underlying sedimentary Limestone (Chalk). Approximately 42km of segmentally lined bored tunnel were completed using pressurized Tunnel Boring Machines (TBM), and over 12km of tunnel were supported utilising Sprayed Concrete Lining (SCL) with spans of up to 17m, along with sprayed concrete, diaphragm wall and piled shafts and underground structures.

This presentation provides an outline of the project, concentrating on the central tunnelled section. The broad geological/hydrogeological setting of the central tunnelled area is described, with an examination in more detail of the perception and reality of tunnelling

in the over-consolidated London Clay. This material has often been described as the ideal tunnelling material, but it is variable and not risk free, and offers challenges for both design and construction. The London Clay has been compared with the similar Keswick and Hindmarsh Clays that underlie much of the Adelaide city area. Tunnel construction utilising TBM and traditional excavation coupled with the use of SCL for support through the London Clay will be discussed. The presentation will consider in particular the influence of the historical experience
of tunnelling in London Clay on modern approaches and risk perceptions.

Dr Oskar Sigl Geoconsult, Asia Singapore

“Design and construction issues which are critical but receive less attention.”

Dr. Sigl graduated as Diploma Engineer (MSc) in 1985 from the Technical University of Graz (Austria), in geotechnics and soil mechanics and in 1991 achieved the PhD in mining engineering at the Mining University of Leoben (Austria). Oskar’s 30 years of experience cover a wide range of projects such as subways, railways, roads, power transmission cables, sewerage mains, underground storage schemes and caverns. Oskar has been working in Singapore since 1997, where he was involved in the detailed design of almost all major underground infra structure projects. This includes the MRT lines, high voltage transmission cable tunnels, underground expressways and deep sewer tunnels. Outside of Singapore, Dr. Sigl was involved
in leading roles in the design of underground transportation systems in Dubai, Perth, Brisbane, Sydney, Hong Kong, Kuala Lumpur as well as the design of underground oil and fuel storage cavern schemes in Saudi Arabia, India and the UAE.

The presentation is intended to highlight and discuss the solution to major challenges of planning underground projects in urban environments, which are not in the forefront of attention. This is related to the construction of entrances, cross passages and other critical structures, which very often do not receive the technical attention they would deserve. These discussions are presented in the form of examples from the viewpoint of a practitioner, who is deeply involved in
the actual design for the implementation of such projects. Infrastructure in large cities is getting denser over time. Actual geotechnical challenges often relate to the application of innovative methods of construction in order
to minimize potential construction impact or disruption. The presentation will focus on the application of “unusual” design considerations and construction methods and related design and construction challenges.

Engineers Australia members participating in AGS technical sessions can record attendance on their personal CPD logs. Members should refer to Engineers Australia CPD policy for details on CPD types, requirements and auditing guidelines.