Minimizing Risk

Minimizing Risk

 

IMS Tunnel Consultancy offers specialist tunnel and related geotechnical services in the Asia Pacific Region including:

  • Selection of route alignment for major transportation and utility infrastructure balancing constraints and opportunities for different forms of construction.
  • Early identification of key constraints and construction issues in both remote and built up areas.
  • Detection of adverse geological conditions by quality site investigations.
  • Ground characterization using different classification systems.
  • Selection of appropriate technology for tunnelling works.
  • Risk sharing contracts for major tunnelling works.
  • Investigation of tunnelling problems.
  • Maximizing TBM performance on site.
  • Quantified risk analysis (QRA) as a decision making tool.

 

 

Why Bored Tunnels?

Why Bored Tunnels?

Bored Tunnel options offer:

  • Improved route segregation and security
  • Shorter routing
  • Minimum long term environmental impact
  • Less land take and acquisition problems
  • Fewer objections
  • No barriers to future planning at surface level

Bored Tunnelling minimizes:

  • Atmospheric and water pollution
  • Visible and Audible construction works
  • Public inconvenience/loss of travelling time
  • Business disruption
  • Programme constraints
  • Land requirements and associated issues
  • Loss of revenue from tourism
  • Complaints to Government

Maximizing Opportunities

Maximizing Opportunities

The IMS Tunnel Consultancy can help identify opportunities at all stages in the development of tunnelling projects offering:

  • Lateral thinking during the early stages for minimizing the impact of infrastructure, realizing land development opportunities, innovative use of underground space, deferring costs by phased construction and planning for different tunnelling methods.

  • Design of tunnels according to purpose and Clients maintenance requirements.

  • Technical innovation and close co-operation with Contractors, through design and construct contracts for example.

  • Identification of potential BOT or cost reimbursable contract opportunities; helping bridge gaps between tunnel Owners and Contractors by providing a common aim to complete projects within time and budget.

  • Identification of opportunities for mechanised excavation by TBM for high speed, low impact tunnelling.

Technical Innovation

Technical Innovation - Appropriate Technology

Since 1978 the company's principal, Dr. Ian McFeat-Smith has resided in Hong Kong working on 56 bored tunnel contracts in Hong Kong and Asia and has been responsible for:

  • High Quality targeted site investigation for bored tunnels including for example the drilling of of horizontal boreholes up to 1km long.

  • Design of smaller diameter, shotcrete lined tunnels for housing gas mains, sewers and high powered transmission lines.

  • FLAC and UDEC design applications.

  • Asia's first (successful) hard roc tunnel boring machines (TBM) including high performance, double shielded applications EPBMs in mixed face conditions and fully mechanised microtunnelling options for bouldery soils.

  • Hong Kong Government's first risk sharing contract.  BACK TO TOP

Advantages

Advantages of TBM Excavation

  • Many of Asia's first TBM applications, for the Tolo Drainage, Hong Kong Electric, Hong Kong Gas, Lantau aqueduct, Philippines Umiray Angat Scheme  and Fanling pipejacked sewer tunnels have proven to be reasonably successful.

  • In hard rock types and soils with boulders, TBM's have achieved average advance rates four times greater than normally achieved by conventional means.

  • The avoidance of blast damage with hard rock TBM's results in substantial costs savings for support purposes.

  • TBMs avoid the effects of blast vibrations on adjacent structures on residential areas.

  • TBM excavation in soft ground substantially reduces settlements and its effects on adjacent structures.

  • Mechanised tunnelling is non-labour intensive and leads to safer working conditions.

  • TBMs require fewer access and spoil disposal sites

  • The overall costs of TBM tunnelling reduces as the length of tunnels increase.

  • Hard rock TBMs are currently available to excavate tunnels from about 1.8-14.0 diameter.

  • TBMs are creating new opportunities, offering solutions not previously realized.

Route Alignment Evaluation

Route Alignment Evaluation

Bored tunnel, immersed tube, bridge, at-grade, cut and cover and elevated structure options have been evaluated using a computer-based numerical scaling and weighting system for a variety of projects including Route 3 Expressway, Sham Tsang Link, Central Kowloon Route, MTR Kennedy Town extension, West Rail and the Jakarta Metro.  Evaluation criteria such as engineering, operation, costs, environment and planning impact were used to compare alternative alignments and establish rankings.  Scaling and weighting of the evaluation criteria were altered to carry out sensitivity analyses for optimum route selection. 

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Criteria Weighting Option C4A Option C2 Options D1

100 Bridge Bored Tunnel Immersed Tube

Engineering





Construction Feasibility

15 Medium High Low

Programme

8 Fair Fair Poor

Waterway Impacts

2 Medium Fair V-High

25 5.3 6.6 2.1

Operational





Road Geometry

5 V-Good Poor Good

D. Goods Vehicles

1 Good Poor Poor

Accessibility

5 V-Good Fair Fair

Traffic Con. & Surveillance

1 V-Good Poor Poor

Navigational Hazards

2 High V-low Low

Route Security

5 Medium High High

Safety/Emergency Issues

1 Good Poor Poor

20 6.5 4.7 5.4

Cost





Capital Costs

20 Low Low Medium

Annual Operating Costs

6 V-low Medium Medium

Land Requirements

3 High Low Low

Economic Benefits

1 Excell Good Fair

30 7.6 7 5.2

Environmental





Noise Impact

5 Worst Better Better

Air Quality Impact

5 Medium Worse Worse

Water Quality Impact

5 Better Best Worst

Visual Impact

3 Worse Best Best

Wate Disposal

1 Worst Worse Medium

Terrestrial Ecology Impact

1 Worst Best Best

20 4.1 7.1 4.8

Planning Impact





Impact on Ma wan

* * * *

Impact on TW West

4 High Low V-Low

Impact on Lantau

1 Low V-Low V-Low

5 3.5 8 10

SCORE (Maximum=10)


5.8 6.5 4.6

RANK


2 1 3

IMS Tunnel Consultancy (Limited) provides specialist services for tunnelling projects that are International, Professional and Independent of any Client, Contractor, Consultant, Manufacturer or Product. Support is provided to prospective tunnel Owners, Consultants and Contractors with the overall aim of:

  • Minimizing risk associated with complex tunnelling works.

  • Maximizing opportunities at the concept , feasibility, design, tender and construction stages.

In order to provide a full multi-disciplinary service to the industry the IMS Tunnel Consultancy can draw upon support from several associated companies including the Meinhard & Alliance (MEIMS) with over 1000 staff in the Civil, Structural and Mechanical & Electrical disciplines based in 19 permanent offices throughout Australia and Asia including Hong Kong, Singapore, Bangkok, Ho Chi Minh City, Kuala Lumpur, Jakarta, Brunei, Karachi, Manila, Port Moresby and Wellington. 

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