1. Risk Management on Tunnelling Projects Warwick University MSc course
London Bridge Associates
John Keys
Risk Management on Tunnelling Projects
Warwick University MSc course

2. Introduction to Risk Management Identification of tunnelling risks
London Bridge Associates
Introduction to Risk Management
Identification of tunnelling risks
Risk analysis and risk assessment tools
Introduction to the Risk Workshop

3. What is risk management? - Definitions
London Bridge Associates
What is risk management? - Definitions
Hazard is something with the potential to cause harm or change the desired outcome
Risk is the likelihood of a hazard occurring x consequence of a hazard
Risk Analysis is the process of identifying risk factors and the quantification of those factors (estimating likelihood and magnitude of impacts)
Risk assessment is the tool whereby risks are evaluated in terms of their likelihood and consequence and mitigation measures identified
Risk Mitigation is the process of developing a plan to respond or deal with risk on a project
Risk Register is a method for recording the project risks for subsequent management

4. Risk Assessment process
London Bridge Associates
Risk Assessment process
Hierarchy of Risk reduction
Eliminate at Source
Control
Monitor
Initial Risk
Consequence
Unacceptable Risks
Risk cannot be justified except in extraordinary circumstances
Tolerable only if risk reduction is impracticable or if the cost is grossly disproportionate to the improvement gained
ALARP Zone
Residual Risk
Tolerable if cost of reduction would exceed the improvement gained
Likelihood
Negligible Risks

5. What risk assessment tools are available?
London Bridge Associates
What risk assessment tools are available?
Risk assessments can be undertaken using either
Qualitative judgements (high / medium / low risks ) or
Quantitative values (numerically as derived from case histories / databases)
Consider practicality of assessments
Availability of reliable data
Diversity of each tunnel’s characteristics

6. What risk assessment tools are available? Risk Analysis tools
London Bridge Associates
What risk assessment tools are available?
Risk Analysis tools
Fault tree analysis
Event tree analysis
Decision tree analysis

7. Why do we need Risk Management?
London Bridge Associates
Why do we need Risk Management?
Why do we need Risk Management?

8. Identification of tunnelling risks?
London Bridge Associates
Identification of tunnelling risks?
The Joint Code states:
“Hazards shall be identified and evaluated on a project-specific basis and their consequent risks shall be identified and quantified by Risk Assessments through all stages of a project “
Project Development Stage (conceptual design)
Detailed Design Stages
Procurement Stage
Construction Stage
Operational stage for any stipulated maintenance period. 8

9. Joint Code of Practice for Tunnelling
London Bridge Associates
Joint Code of Practice for Tunnelling
Section 8 – Design
Clause states
“The fundamental objective of the design process is that of achieving a robust design, that is a design where the risk of failure or damage to the Tunnel Works or to a Third Party from all reasonably foreseeable causes, and including health and safety considerations, is extremely remote during the construction and the design life of the Tunnel Works. High consequence but low frequency events that could affect the works or a Third Party shall also be considered”

10. Joint Code of Practice for Tunnelling
London Bridge Associates
Joint Code of Practice for Tunnelling
Section 8 – Design
Clause states
“The design process shall include, where appropriate, sensitivity studies to assess the impact of:
a) construction tolerances
b) variation in geotechnical design values
c) variation in materials characteristics
d) variation in workmanship and geometry
e) methods of construction and the implementation of mitigation/contingency measures
f) natural perils exposure in the region of the project such as flood, storm, seismic or tidal effects

11. London Bridge Associates
Joint Code of Practice for Tunnelling
Section 8 – Design
Clause states
“The Designer shall ensure that adequate construction expertise is available to undertake formal reviews of the design to assess and confirm the appropriateness of the design in terms of Constructability, including health and safety considerations in relation to BS6164”

12. London Bridge Associates

13. London Bridge Associates
Questions?

14. Dry Creek Road Tunnel Project
London Bridge Associates
Risk Management Workshop
Dry Creek Road Tunnel Project

15. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project

16. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project

17. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project
Background to the project
$400m road tunnel in Australia
Ring road around the town of Yarra Awali
Client designed scheme
Funded by state taxes
Environmental constraints
Golf course
Residential areas
West Portal in a flood plain

18. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project
Background to the project
Detailed design
3km long 110m2 excavated face area
Boreholes / seismic surveys / Previous borehole data
Tunnel alignment
Minimise environmental impact
Steep gradients
Over burden
Utilities
High rise luxury hotel
Portals positioned to minimise impact
Conservation area and a flood plain
Old Quarry
Geology
Hydrology

19. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project
Background to the project
Historical Land use
Ground water extraction for irrigation
Small dwellings still extract water
Local brewery
Abandoned quarry on west side

20. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project
Background to the project
Contractual
NEC form of contract with all risks transferred to the Contractor
Pain / Gain incentives
Design and Construct Contract
Novated design - NATM methodology
Contractor to price risks
1 month to bid the works

21. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project
Background to the project
NATM construction method
Alternative designs
Cheapest tender submission $400m
Contractor lacked resources
JV Board decision on passing on risk

22. Dry Creek Road Tunnel Project
London Bridge Associates
Dry Creek Road Tunnel Project
You are the construction company for the Dry Creek Road Tunnel project.
You have a meeting tomorrow with a group of Insurance Companies
The Insurer company have asked you to identify all the key risks and convince them that you have the risks under control before they will provide cover to the project
Task 1
Your brief is to identify the top risks associated with the project and what control measures you will be putting in place to manage those risks.
Rank the risks in order of priority starting with the highest risks first and an explanation why you perceive these risks as priorities.
Task 2
Identify the actions and measures the Client and the Designer should have put in place to ensure that the project had the greatest chance of success.