TransportationCentral Subway
A 3.1-mile underground extension of the Market Street subway, delivering twin bored tunnels, three underground stations and a cavern beneath an operating city centre.
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Tunnels & Underground Engineering
From feasibility studies to detailed design, to engineering and management services during construction.
For more than 25 years we have provided design and consulting for all phases of tunnel and underground engineering projects — from feasibility studies through detailed design, to engineering and management services during construction.
We are recognised as experts in the design of tunnels, deep shafts, temporary works, portal and slope stability, deep foundations, building protection measures, and ground improvement by grouting, freezing and dewatering.
We work directly for government agencies, contractors and private-sector owners, and as a specialty subconsultant to other engineering firms. Our leading-edge designs consider the full range of construction methods, including open-beam tunnel boring machines for hard rock, shielded rock machines, earth pressure balance and slurry machines for soft ground, and conventional underground excavation using sequential excavation methods or drill-and-blast.
Our expertise
- Tunnels, caverns, cross-passages and adit structures
- Deep shaft structures and shaft linings
- Cut-and-cover structures and underpinning
- Temporary works and support of excavation systems
- Pressure tunnels and conveyance pipelines
- Tunnel ventilation design, modelling and testing
- Ground improvement: grouting, freezing and dewatering
- Portal and slope stability
- Building protection and settlement mitigation
- Private underground and wine cave structures
Where we work
- Transportation — metro, commuter rail, light rail and highway tunnels
- Water — potable supply, conveyance, storage and outfalls
- Wastewater — trunk sewers, interceptors, CSO storage and outfalls
- Energy & Mining — hydropower, pumped storage and mine access
How we engage
- Feasibility and alignment studies
- Detailed design and design review
- Construction phase engineering
- Design of temporary works
- Monitoring and instrumentation design
- Tunnel inspection and condition assessment
This service, in practice.
Projects using Tunnels & Underground Engineering.
TransportationCentral Subway project details
TransportationNorthgate Link Extension
A 4.4-mile light rail extension including two cut-and-cover stations, a cut-and-cover crossover and 2.5 miles of underground guideway.
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TransportationSydney Metro City & Southwest
Metro-scale station caverns and twin running tunnels on Australia’s largest urban rail programme.
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TransportationCaldecott Improvement Project
A four-bore highway tunnel through the Oakland Hills, including a 3.5-mile bore and seismic retrofit.
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TransportationSR 99 Alaskan Way Viaduct Replacement
A four-lane, four-block downtown viaduct built as a structurally independent tunnel beneath a working street.
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TransportationCoos Bay Rail Tunnel Rehabilitation
Rehabilitation and rock-lining repair of six miles of historic single-track rail tunnel in basalt.
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We rarely work in only one discipline.
Trenchless Engineering
Consulting services for small-diameter tunnels and trenchless technologies.
Tunnel Inspection & Rehabilitation
Inspection and rehabilitation services that improve the safety, functionality and longevity of underground structures.
Advisory Consulting
Our consulting services go deeper than design — we advise at every stage of project development.
Engineering Consulting
Multi-disciplinary engineering, analysis and digital delivery for complex underground assets.
Construction Management
Good construction management paves the way for safe, efficient project execution.
Construction Claims Services
Contractual clarity from notice to resolution, supported by forensic engineering.
Talk to the engineers who do the work.
Every enquiry is reviewed by a principal engineer in the relevant practice — not a sales team. If your question is a technical one, you will get a technical answer, and if we are not the right firm for the job, we will say so.
Or email us directly at support@hoffmantunnels.com.
