Technical Appendix P - Ground Movement and Land Stability Part 1

221 Pages·2016·5.88 MB·English

Melbourne Metro Rail Project 20 April 2016
Revision: C1

MMR-AJM-PWAA-RP-NN-000827 Reference: CMS332569

Ground Movement and Land Stability
Impact Assessment
Melbourne Metro Rail Authority
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121 Exhibition Street
Melbourne VIC 3000
PO Box 23061 Docklands VIC 8012 Australia

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Document control
Report title Ground Movement and Land Stability Impact Assessment
Document ID MMR-AJM-PWAA-RP-NN-000827 Contract No. CMS332569
File path
Client Melbourne Metro Rail Authority Client contact Daniel Cullen
Revision
Rev Date Prepared by Author Verifier Approver
details/status
Antoinette
Final issue for Walshe Antoinette
C1 20/04/2016 Mark Tansley Lisa Ryan
Exhibition Anthony Walshe
Bennett
Current revision C1

Approval
Approver
Author signature
signature
Name Antoinette Walshe Name Lisa Ryan

© Copyright 2016 AJM Joint Venture. The concepts, data and information contained in this document are the property of AJM Joint
Venture. No part of this document may be reproduced, used, copied, published or adapted for use except in accordance with the
provisions of the Copyright Act 1968 or with the consent of AJM Joint Venture.
This report has been prepared on behalf of, and for the exclusive use of Melbourne Metro Rail Authority (“MMRA”), and is subject to,
and issued in accordance with, the provisions of the contract between AJM Joint Venture and MMRA. AJM Joint Venture makes no
representations and undertakes no duty to any third party who may use or rely upon this report, and accepts no liability or responsibility
whatsoever for, or in respect of, any use of, or reliance upon, this report by any third party. Any third party using and/or relying upon this
report accepts sole responsibility and all risk for using and/or relying on this report for any purpose.
This report has been produced from information sourced from MMRA and/or from other sources, relating to the dates and periods
referred to in this report. Except as otherwise stated in the report, AJM Joint Venture has not attempted to verify the accuracy or
completeness of any such information. If the information is subsequently determined to be false, inaccurate or incomplete then it is
possible that our observations and conclusions as expressed in this report may change. The passage of time, manifestation of latent
conditions or impacts of future events may require further examination of the project and subsequent data analysis, and re-evaluation of
the data, findings, observations and conclusions expressed in this report.
This report should be read in full and no excerpts are to be taken as representative of the findings.

File MMR-AJM-PWAA-RP-NN-000827 20 April 2016 Revision C1
Contents
Glossary and Abbreviations i
Executive Summary iv
1 Introduction 1
1.1 Project Description 1
1.2 Purpose of this Report 2
1.3 Project Precincts 2
1.4 Study Area 3
1.5 Proposed Construction Methods 6
1.6 Key Issues 8
2 Scoping Requirements 11
2.1 EES Objectives 11
2.2 EES Scoping Requirements 11
3 Legislation, Policy and Guidelines 13
4 Background 15
4.1 Regional Context 15
4.2 Geological Setting 16
4.3 Hydrogeological Setting 16
4.4 Ground Movement Mechanisms 19
4.5 Summary of Current Land Use 25
4.6 Existing Structural Conditions 26
5 Methodology 27
5.1 A Collaborative Approach 27
5.2 Estimation of Potential Ground Movement 30
5.3 Levels of Impact Assessment 33
5.4 Risk and Impact Assessment 36
5.5 Stakeholder Engagement 42
5.6 Assumptions 43
6 Estimated Ground Movement 45
6.1 Preliminary Ground Movement Estimates 45
6.2 Early Works 50
6.3 Potential Zone of Influence 51
6.4 Timeline of Ground Movement Occurrence 52
6.5 Measures to Limit Ground Movement 52
7 Ground Movement Risk Assessment 64
8 Building Impact Assessments 69
8.1 Early works 73
8.2 Heritage Buildings 74
8.3 Approved Developments 77
9 Civil Infrastructure Impact Assessments 80
9.1 Rail 83
9.2 Tram Lines and Road Pavements 84
9.3 Existing Tunnels 86

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9.4 Lloyd Street Bridges and Essendon Flyover 90
9.5 West Melbourne Terminal Station 90
9.6 CityLink Viaduct 90
9.7 Princes Bridge 91
9.8 Utilities 92
10 Parkland Impact Assessments 97
11 Further Work 99
11.1 Additional Studies 99
11.2 Stakeholder Engagement 99
11.3 Development of Acceptability Criteria 100
11.4 Instrumentation and Monitoring 100
11.5 Condition Surveys 103
11.6 Construction Stage Control Measures 103
12 Environmental Performance Requirements 105
13 Conclusions 108
14 Limitations 110
References 112

Appendices

Appendix A
Golder Associates Interpreted Geological Setting EES Summary Report
Appendix B
Golder Associates Ground Movement Assessment EES Summary Report
Appendix C
Preliminary Excavation Induced Settlement Contour Drawings
Appendix D
Preliminary Primary Consolidation Settlement Contour Drawings

List of Tables
Table 1-1 Precinct Summary 3
Table 1-2 Summary of potential Melbourne Metro under which this assessment was prepared 6
Table 1-3 Haack classification system for water tightness of underground structures 8
Table 1-4 Key issues associated with the Concept Design 8
Table 1-5 Key issues associated with alternative design options 9
Table 2-1 EES Evaluation Objective: Land stability 11
Table 2-2 Scoping Requirements for Land Stability 11
Table 3-1 Primary legislation relating to potential ground movement and land stability 13
Table 4-1 Matrix summarising predominant land use functions by precinct 25
Table 5-1 Relationship between EES reports 27
Table 5-2 Summary of Ground Movement Assessment Components 28
Table 5-3 Adopted Tunnelling Induced Settlement Parameters 30
Table 5-4 Melbourne Metro Likelihood rating criteria 37
Table 5-5 Melbourne Metro Ground Movement and Land Stability Consequence Framework 37
Table 5-6 Risk Assessment Matrix 38
Table 5-7 Impact ratings for buildings (after Burland, 1995 and Boscardin & Cording 1989) 39
Table 5-8 Impact ratings for road pavements*, tram ways, kerbs and footpaths (Hudson-Smith & Grinceri) 41
Table 5-9 Impact ratings for Utilities (Attewell et al. (1986) and Bracegirdle et al. (1996)) 41
Table 5-10 Summary of stakeholder engagement 42

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Table 5-11 Basis and Assumptions of Methodology 43
Table 6-1 Ground Movement Control Measures inherent in the Concept Design 53
Table 6-2 Ground Movement Control Measures inherent in the Alternative Design Options 56
Table 7-1 Risk Register for Ground Movement Impact Assessment 65
Table 8-1 Summary of Impact assessment results for selected buildings 70
Table 8-2 Building impacts due to combined effects 73
Table 8-3 Estimated Impacts to Selected Heritage Buildings 75
Table 8-4 Summary of results from assessment of selected approved developments 78
Table 9-1 Summary of Impacts on Selected Key Civil Infrastructure included in preliminary assessments 80
Table 9-2 Civil Infrastructure impacts due to combined effects 83
Table 9-3 Ground Deformation results at existing rail 83
Table 9-4 Ground Deformation Estimates at selected locations across the proposed alignment 85
Table 9-5 Potential mitigation measures for impacts at City Loop crossing 87
Table 9-6 Estimated impacts on selected Existing Utilities 93
Table 10-1 Waterways and Parklands that were considered in this assessment 97
Table 11-1 Typical Monitoring Response Strategy 102
Table 12-1 Environmental Performance Requirements for Ground Movement and Land Stability 106

List of Figures
Figure 1-1 Map of the proposed Melbourne Metro alignment and five underground stations 2
Figure 1-2 Melbourne Metro Precinct Location Plan 5
Figure 4-1 Long Section - Interpreted Geological Profile 18
Figure 4-2: Road header excavation 20
Figure 4-3 Exaggerated ground settlement troughs for single and twin tunnels 20
Figure 4-4 Example of an excavation and support sequence for a cavern 21
Figure 4-5 Open cut excavation induced ground movement 23
Figure 4-6 Example slope stability model with soil nail support 25
Figure 5-1 Overview of AS/NZS ISO 31000-2009 Risk Process 36
Figure 6-1 Western Portal: Comparison of consolidation and excavation induced settlement 47
Figure 6-2 Arden station: Comparison of consolidation and excavation induced settlement 48
Figure 6-3 South bank of the Yarra River: Comparison of consolidation and excavation induced settlement 49
Figure 6-4 Domain station: Comparison of consolidation and excavation induced settlement 50
Figure 6-5 Potential Zone of Influence, relating to Ground Movement Sheet 1 of 5 59
Figure 6-6 Potential Zone of Influence, relating to Ground Movement Sheet 2 of 5 60
Figure 6-7 Potential Zone of Influence, relating to Ground Movement Sheet 3 of 5 61
Figure 6-8 Potential Zone of Influence, relating to Ground Movement Sheet 4 of 5 62
Figure 6-9 Potential Zone of Influence, relating to Ground Movement Sheet 5 of 5 63
Figure 9-1 Preliminary model of City Loop tunnels and Melbourne Central Station relative to proposed works 88
Figure 9-2 Area potentially requiring ground treatment at the CityLink crossing 89
Figure 9-3 General Elevation and Longitudinal Section through Princes Bridge 91

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Glossary and Abbreviations

Term Definition
AH Act Aboriginal Heritage Act 2006
AHD Australian Height Datum
AJM JV Aurecon, Jacobs and Mott MacDonald Joint Venture
Potential alternative solutions to the project’s concept design or route alignment within the proposed
Alternative
project boundary which have been assessed as part of the EES process. These would provide for
Design Option
flexibility during project delivery whilst still allowing integrated assessment of the project.
Aquifer Rock or sediment in a formation that is saturated and sufficiently permeable to transmit of water
A low permeability unit that can store groundwater and also transmit it slowly from one aquifer to
Aquitard
another
An existing or proposed structure, pavement or utility whose stability, form or function may be
Asset
impacted by ground movement
BCA Building Code of Australia
BS British Standard
BTS British Tunnelling Society
CBD Central Business District
CHMP Cultural Heritage Management Plan
CIC Commercial in confidence
The Concept Design demonstrates a feasible way for the project to achieve the Victorian
Government’s objectives and meet the performance requirements for the Melbourne Metro. It
Concept Design provides the basis for the EES to assess the expected potential environmental risks and impacts,
and demonstrates that impacts can be managed. It recognises that the project could be configured
differently, provided it meets the Government’s objectives and performance requirements.
Condition A survey of an asset that is undertaken prior to construction works. A post construction condition
Survey survey may be undertaken, if required.
A consequence is the outcome of an event and has an effect on objectives. A single event can
Consequence generate a range of consequences which can have both positive and negative effects on objectives.
Initial consequences can also escalate through knock-on effects.
CSR Concept Summary Report
An impact adversely affecting structural integrity, serviceability, performance or aesthetics of an
Damage
asset
Department of Environment, Land, Water and Planning (formerly Department of Transport,
DELWP
Planning, Land and Infrastructure)
EMF Environmental Management Framework

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Term Definition
EMP Environmental Management Plan
EMS Environmental Management System
An environmental aspect is an element or characteristic of an activity that interacts or can interact
Environmental with the environment. Environmental aspects can cause environmental impacts. They can have
Aspects either beneficial impacts or adverse impacts and can have a direct and decisive impact on the
environment or contribute only partially or directly to a larger environmental change.
An environmental impact is a change to the environment that is caused either partly or entirely by
one or more environmental aspects. An environmental aspect can have either a direct and decisive
Environmental
impact on the environment or contribute only partially or indirectly to a larger environmental change.
Impact
In addition, it can have either a beneficial environmental impact or an adverse environmental
impact.
Environmental A detrimental effect due to the implementation of Melbourne Metro on the sustainability of the
Issue surrounding natural environment
EPA Victorian Environment Protection Authority
EPB (TBM) Earth Pressure Balance (Tunnel Boring Machine)
EPBC Act Environment Protection and Biodiversity Conservation Act 1999
FFG Act Flora and Fauna Guarantee Act 1988
GQRUZ Groundwater Quality Restricted Use Zone
IAU Impact Assessment Unit (within DELWP)
Likelihood is the chance that something might happen. Likelihood can be defined, determined, or
Likelihood measured objectively or subjectively and can be expressed either qualitatively or quantitatively
(using mathematics).
m BGL Metres below ground level
Siltstone with interbedded sandstone, slightly weathered to fresh. Joints relatively closely spaced.
MF1 Blocky rock mass with joint spacing of approximately 200 mm. Some faults and shears. Dyke
intrusions relatively unweathered
Siltstone and sandstone, generally moderately weathered. Blocky rock mass containing
MF2
decomposed seams, shears and faults. Dykes where present are weathered to clay
Siltstone and sandstone, generally highly weathered. Siltstone beds may be extremely weathered
MF3 whilst sandstone is less weathered. Closely spaced discontinuities. Contains decomposed seams.
Dykes where present are weathered to clay
Generally extremely weathered siltstone and sandstone, predominantly hard clay. Discontinuities
MF4
may present as fissures. Dykes where present are completely weathered to clay
MFB Metropolitan Fire Brigade
MMRA Melbourne Metro Rail Authority
MTM Metro Trains Melbourne
MURL Melbourne Underground Rail Loop (City Loop)

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Term Definition
A computer model that is designed to simulate and reproduce the mechanisms of a particular
Numerical Model
system
Channel in a basal geological unit that is infilled with layered sediments and lava flows that are
Palaeovalley
much younger in geological age than the basal unit
The proposed project boundary established for the project defines the area in which the project
components would be contained. The proposed project boundary encompasses all areas that would
Project
be used for permanent structures and temporary construction areas (both above and below
Boundary
ground). It provides the basis for the specialist assessments undertaken for the EES and would be
refined through the EES process.
PTV Public Transport Victoria
PZoI Potential Zone of Influence
RL Reduced Level, a level relative to a stated datum
RM Act Road Management Act 2004
Sound In good condition, not damaged
SLS Serviceability Limit State
An impermeable barrier incorporated into a final lining of an underground excavation to limit the
Tanked
inflow of water
Tunnel Boring Machine, circular in cross section, it is used to excavate tunnels through various
TBM
geological conditions
TI Act Transport Integration Act 2010
TRG Technical Reference Group
UCS Unconfined Compressive Strength
UDL Uniform Distributed Load
ULS Ultimate Limit State
VCCC Victorian Comprehensive Cancer Centre
VHR Victorian Heritage Register

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Executive Summary
The proposed Melbourne Metro Rail Project (Melbourne Metro) comprises two rail tunnels from Kensington
to South Yarra, travelling underneath Melbourne Central Business District (CBD), as part of a new Sunbury
to Cranbourne/Pakenham line to form the new Sunshine-Dandenong Line. Five new underground rail
stations would connect the new system with existing transport, business, and health and education hubs.
As in the case of any large tunnelling project, the potential for ground movement exists where excavations
would be undertaken as part of Melbourne Metro works. Ground movements may occur above and adjacent
to Melbourne Metro works due to underground excavations; open cut excavations; consolidation settlement
of compressible soils due to groundwater drawdown and/or slope instability.
Buildings, utilities and civil infrastructure such as roads, rail lines and bridges may be subjected to the effects
of ground movements (settlement) caused by construction of the tunnels, stations, shafts and portals and/or
associated drawdown effects.
A Ground Movement and Land Stability Assessment was undertaken by Golder Associates and a summary
report describing this work is appended to this report along with an Interpreted Geological Setting Summary
Report. The Golder Associates assessment outputs are integrated through this report and informed the
preliminary assessment, by AJM JV, of the potential ground movement effects on buildings, structures and
services along the Melbourne Metro alignment.
The Potential Zone of Influence relating to ground movement is defined by the estimated 5 mm excavation
induced ground surface settlement contours and the estimated 10 mm consolidation settlement contours.
Experience from tunnelling projects over past decades has shown that structures subjected to smaller
settlements than these have negligible or no effects from the movements. Structures and underground
services located between the contours defined by the above zones are considered within the Potential Zone
of Influence. The potential effects of ground movement have been assessed for a representative sample of
buildings, utilities and key civil infrastructure along the alignment.
Based on the current interpreted geological models, the tunnels alignment would be predominantly located
within favourable geological units for ground stability, while meeting the key requirement to achieve safe
design gradients for Melbourne Metro rail operations.
This impact assessment reviewed the possible degree of damage to buildings and infrastructure that would
be caused by the excavations associated with Melbourne Metro, considering the structural type, the current
condition of the structure and the differential settlement across the structure. The impact assessment
established the possible mechanisms leading to ground movement, estimated the settlements, and predicted
the category of potential damage.
Generally, the potential impacts to property were found to be negligible or minor and within acceptable
parameters. In some cases, mitigation would be required to achieve acceptable outcomes and limit the
predicted effects so that there would be no impacts greater than minor. For such cases, the assessment
includes descriptions of the mitigation measures that could be applied, and where management or mitigation
would need to be applied. These measures are standard tunnelling construction practices that have already
been included in the assessments and the derivation of the impacts. There remain a number of structures
where the predicted damage level is moderate. These would require further investigation based upon
additional data along with discussion with the relevant stakeholders to confirm that the potential impacts
would be acceptable, or to identify any further mitigation measures necessary.
Prior to construction, detailed condition surveys of potentially affected structures would be conducted that
may identify increased vulnerability of some structures. These structures could have higher susceptibility to
adverse impacts from ground movements. In these cases, additional mitigation measures may be required.

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A list of the anticipated ground movement risks is provided. Completion of further geotechnical and
hydrogeological investigations and interpretation of these conditions prior to construction would assist in
estimating identified risks. Effective implementation of the mitigation measures would be expected to reduce
the majority of potential impacts to either negligible or minor.
With the mitigation measures applied, the estimated impacts associated with the described risk pathways for
ground movement are considered to be acceptable. The identified mitigation measures are typical and
proven tunnelling construction techniques, and would be applied effectively with the appropriate
management in place.

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