Tunnelling and Underground Works
SCL and cast-in-situ lining
SCL and cast-in-situ lining
Sprayed Concrete Lining (SCL)
We are a market-leading Sprayed Concrete Lining (SCL) specialist contractor, recognised for delivering safe, high-quality tunnel linings in some of the most demanding ground and environmental conditions. SCL is widely acknowledged as one of the most technically challenging activities in tunnel construction, requiring precise control of materials, equipment, geometry and workmanship. Our accumulated experience, specialist plant and highly trained workforce place us in a strong position to support projects from early design input through to final lining completion.
Our SCL capability spans primary and secondary applications, temporary and permanent works, and complex geometries including enlargements, junctions and caverns. We work closely with designers and clients during Early Contractor Involvement (ECI) to advise on buildability, sequencing, thickness optimisation and quality control, ensuring safe excavation support and long-term asset performance.
Our operators are trained to the highest standards and supported by advanced technologies, including computer-assisted boom control, laser scanning and real-time profile verification. Virtual reality and simulator-based training further enhance safety, consistency and ergonomic performance, allowing our nozzlemen and operators to maintain precision while reducing fatigue and manual handling risks. The result is a controlled, repeatable and high-quality lining solution delivered safely and efficiently.
Tunnel Waterproofing (Membrane and Spray Applied)
Effective waterproofing is critical to the durability and performance of underground structures. We provide comprehensive tunnel waterproofing solutions, tailored to ground conditions, groundwater pressures and design life requirements. Our experience covers both traditional sheet membrane systems and modern spray-applied waterproofing technologies.
Membrane systems are installed with meticulous attention to detailing, including interfaces at construction joints, penetrations, drainage elements and terminations. Where programme, geometry or access constraints exist, we also deliver spray-applied waterproofing systems that provide a fully bonded, seamless barrier, reducing the risk of water tracking and simplifying installation in complex profiles.
Our teams understand the importance of integrating waterproofing with excavation sequencing, primary lining tolerances and secondary lining construction. Quality assurance is embedded throughout installation, with inspection regimes, testing and verification to ensure long-term resistance to water ingress and compliance with specification requirements.
Spray Applied Secondary Lining
Where a sprayed solution is selected for the permanent works, we deliver spray-applied secondary linings that provide structural capacity, durability and finish quality in a single integrated process. This approach can offer programme efficiencies and enhanced flexibility, particularly in constrained or irregular tunnel geometries.
Our expertise ensures accurate thickness control, surface finish and bond performance, supported by digital scanning and verification techniques. Material selection and mix design are carefully controlled to meet structural, durability and fire performance requirements. The sprayed secondary lining is seamlessly coordinated with waterproofing systems, reinforcement and service interfaces to achieve a robust and compliant permanent lining solution.
Cast In-Situ Secondary Lining
For tunnels requiring a traditional cast in-situ secondary lining, we provide full delivery using proprietary travelling formwork systems or bespoke timber shuttering, depending on tunnel size, geometry and programme requirements. Our experience covers a wide range of tunnel diameters and lengths, including straight drives, curves, enlargements and transitions.
Proprietary formwork systems are used to achieve high productivity, consistent geometry and excellent finish quality on long or repetitive tunnel sections. Where non-standard geometry or local constraints exist, bespoke timber shuttering is designed and constructed to suit the specific requirements of the works, ensuring accuracy and constructability without compromising quality.
Our teams manage all aspects of reinforcement fixing, concrete placement, curing and strike, with strict controls on tolerances, surface finish and interface detailing. Integration with waterproofing systems, drainage and embedded items is carefully planned to ensure durability, serviceability and long-term asset performance.
TBM/Segmental Lining Tunnelling
TBM/Segmental Lining Tunnelling
We deliver segmental tunnelling solutions using Tunnel Boring Machines (TBMs) as either a primary tunnelling method from launch or as a follow-on methodology from pipejacking operations. Our capability spans TBM operations from 3.0 m outer diameter through to and exceeding 10 m outer diameter, enabling us to support a broad range of utility, wastewater, energy and strategic infrastructure projects.
Our segmental lining expertise covers the full lifecycle of delivery, including early design input, segment specification and manufacture interface, logistics planning, ring erection and quality assurance. We work collaboratively with clients and designers to optimise segment geometry, gasket systems, reinforcement and durability requirements, delivering watertight, structurally efficient tunnels that achieve both performance and programme certainty.
We have extensive experience delivering long, complex segmental tunnels in highly constrained environments, including major UK infrastructure schemes such as London Power Tunnels 2, where precision, asset protection and interface management with existing live infrastructure are critical. Our teams are experienced in working within congested urban corridors, coordinating shaft construction, launch and reception arrangements, and maintaining strict controls on alignment, settlement and quality.
Our capability has also been demonstrated on nationally significant energy projects, including the Hinkley Point C Fish Return Structure, where segmental and underground works demanded rigorous engineering assurance, integration with marine and coastal interfaces, and close coordination with permanent works design and environmental constraints. These schemes highlight our ability to deliver technically demanding tunnelling works within heavily regulated and safety-critical environments.
We streamline delivery across all stages of design and construction, integrating temporary works, shaft and portal interfaces, plant selection and logistics to provide innovative, sustainable and cost-effective segmental tunnels. Our approach is engineering-led and focused on buildability, risk reduction and long-term asset performance.
Our technical capability includes the planning and execution of compressed air interventions, allowing safe access for inspection, maintenance and cutterhead works in pressurised conditions. These activities are supported by experienced personnel, specialist equipment and robust procedures for pressure control, decompression and occupational health, ensuring interventions are carried out safely and efficiently with minimal impact on programme.
Our experience, knowledge and operational proficiency were further showcased during the Emergency Sea Outfall (ESO) works for the Umm Al Hayman Wastewater Treatment Project, where we successfully recovered a TBM from approximately 10 m beneath the seabed of the Arabian Gulf in just four days. This achievement demonstrated our ability to manage complex marine interfaces, pressurised tunnelling environments and challenging recovery constraints while maintaining programme certainty.
Through a combination of specialist plant, highly skilled tunnelling teams and proven engineering leadership, we provide a robust and adaptable TBM and segmental tunnelling capability, trusted to deliver complex underground infrastructure safely, efficiently and to the highest technical standards.
Microtunnelling and Pipe Jacking
Microtunnelling and Pipe jacking
We deliver a comprehensive range of pipejacking solutions, encompassing microtunnelling, mechanical shield and hand-shield construction, with capabilities covering internal diameters from 600 mm to greater than 3.0 m and individual drive lengths exceeding 2 km. This breadth of capability allows us to tailor the pipejacking methodology to suit ground conditions, alignment constraints, asset sensitivity and programme requirements.
Our microtunnelling operations utilise a cutting-edge fleet of remote-controlled, laser-guided systems, enabling the installation of pipelines with pinpoint alignment accuracy, enhanced safety and minimal surface disruption. By eliminating the need for personnel at the tunnel face, microtunnelling provides a highly controlled solution for installations beneath roads, railways, rivers and densely populated urban environments, while maintaining tight tolerances and delivering watertight, high-quality finishes.
Where project constraints demand greater flexibility, we deploy mechanical shield and hand-shield pipejacking techniques, offering adaptable solutions in variable ground conditions and in areas with high concentrations of existing services. These methods allow close control of excavation and support, enabling effective management of settlement, vibration and interaction with third-party assets, particularly in congested corridors or at critical interfaces.
Our experience spans a wide range of geological environments, from running sands in Kuwait to competent clays in the UK, supported by a diverse fleet of microtunnelling machines, shields and jacking systems configured to suit specific ground conditions and drive requirements. Long-drive pipejacking operations are carefully planned with detailed assessment of jacking forces, intermediate jacking station requirements, lubrication strategies and shaft logistics to ensure performance and reliability over extended distances.
Our engineering-led approach integrates geotechnical understanding, temporary works design, shaft construction and logistics planning, allowing us to manage construction risk proactively while protecting existing infrastructure and minimising environmental and community impact. By offering flexibility in both method and scale, we provide robust, durable and efficient pipejacked tunnel solutions that deliver long-term value and programme certainty
Horizontal Directional Drilling (HDD)
HDD
We deliver engineering-led Horizontal Directional Drilling (HDD) solutions that provide a proven, flexible and low-impact method for installing pipelines and cables across the utilities, energy and infrastructure sectors. Our HDD capability is suited to complex underground installations where surface disruption must be minimised and where precise control of alignment, geometry and interfaces is critical.
Our fleet of HDD rigs ranges from 12-tonne to 500-tonne pullback capacity, enabling us to select the most appropriate plant to suit installation diameter, length, ground conditions and access constraints. We routinely deliver HDD installations for pipelines and cables up to 1.0 m outer diameter, with individual drill lengths extending to 1,000 m, maintaining tight grade and alignment tolerances throughout the bore.
We have extensive experience operating in complex and variable geotechnical conditions, including mixed strata, hard rock, granular soils and groundwater-affected environments. Our approach places particular emphasis on the definition, design and active management of drilling fluids (mud systems), recognising their critical role in bore stability, cuttings transport, lubrication, hydrofracture control and environmental protection. Mud design is tailored to ground conditions and continuously monitored and adjusted throughout drilling operations to manage risk and maintain performance.
Alignment control is central to our HDD delivery. We utilise advanced steering, tracking and surveying techniques to ensure the bore path is achieved accurately, particularly in congested environments where tolerances are tight and interaction with existing utilities, structures and transport corridors must be carefully managed. We work closely with third-party asset owners to define exclusion zones, monitoring regimes and interface controls, ensuring protection of live infrastructure and regulatory compliance throughout the works.
Our specialist capability includes the planning and execution of intersect HDD operations, where multiple bores are required to meet at depth, as well as the management of golden welds, product pipe laydown, welding quality and logistics. We coordinate pipe string fabrication, non-destructive testing, coating integrity, handling and storage to ensure that installation readiness, quality assurance and programme sequencing are fully aligned with drilling operations.
Through integrated planning, experienced crews and robust technical assurance, we deliver safe, accurate and high-quality HDD installations that manage geotechnical risk, protect third-party assets and provide durable underground infrastructure with minimal environmental and community impact.
Direct Pipe
Direct Pipe
We deliver industry-leading Direct Pipe tunnelling solutions, providing a highly efficient hybrid method that combines the precision of microtunnelling with the direct installation of the permanent product pipe. Our capability spans diameters from 600 mm to greater than 2.4 m, supporting both trenchless crossings and long sea outfall installations in challenging ground and marine environments.
Direct Pipe is particularly effective where engineering efficiency, programme certainty and asset performance are critical. The method allows the product pipe to act as the primary temporary support, eliminating the need for separate carrier pipes or secondary installation stages. This significantly reduces construction interfaces, handling risks and overall programme duration, while enhancing alignment accuracy and structural integrity.
We routinely deliver Direct Pipe drives for long-distance installations, including sea outfalls, where control of line, level and ground interaction is essential. The single-step process enables simultaneous tunnel excavation and pipeline installation, reducing surface disruption, minimising environmental impact and providing a robust solution across a wide range of ground conditions, including mixed and water-bearing strata.
Our engineering-led approach integrates geotechnical understanding, launch and reception shaft design, jacking force assessment, lubrication strategies and temporary works coordination. This ensures that Direct Pipe solutions are optimised to manage ground risk, protect third-party assets and maintain construction control throughout the drive.
A key strength of our Direct Pipe capability is our strategic relationships with leading industry equipment and system suppliers. These partnerships allow us to leverage specialist plant, proven cutting heads, jacking systems and guidance technology, ensuring that equipment selection is aligned with ground conditions, diameter requirements and programme constraints. This collaborative approach enhances reliability, innovation and delivery confidence on complex schemes.
Through careful planning, specialist plant and experienced tunnelling teams, we deliver robust, high-quality Direct Pipe installations that provide efficient, durable and low-impact solutions for utilities, energy and marine infrastructure projects.
Auger Boring
Auger Boring
We deliver auger boring and guided auger boring solutions as highly effective trenchless methodologies for short to medium-length crossings where programme certainty, cost efficiency and minimal surface disruption are key drivers. These techniques provide a robust and proven alternative to more complex tunnelling methods, while still offering high levels of control and reliability.
Conventional auger boring is ideally suited to straight-line installations beneath roads, railways and embankments, where ground conditions are predictable and tolerances are manageable. The method combines simplicity with productivity, allowing steel casing installation with continuous spoil removal, reduced plant requirements and rapid set-up. This results in a cost-effective solution with low environmental impact and minimal disruption to surface operations.
Where tighter tolerances, longer drives or greater asset sensitivity are required, we deploy guided auger boring systems. These systems incorporate laser guidance, steering heads and continuous monitoring to achieve enhanced accuracy in line and level, making them suitable for congested corridors and critical interfaces. Guided auger boring bridges the gap between traditional auger methods and microtunnelling, offering improved control at a lower overall cost.
Our approach is engineering-led and innovation-focused, ensuring the selected method aligns with ground conditions, asset protection requirements and project constraints. By integrating ground investigation data, casing design, launch pit geometry and construction sequencing, we deliver trenchless crossings that manage risk effectively while maintaining programme and budget certainty.
Through the intelligent application of auger boring and guided auger boring, we provide practical, innovative and economical trenchless solutions that support utilities, transport and infrastructure projects where efficiency, safety and value are paramount.
Pipe Ramming
Pipe Ramming
We deliver pipe ramming as a robust and highly effective trenchless construction method, offering a sustainable, cost-efficient alternative to traditional open-cut trenching. This technique is particularly well suited to short, straight crossings beneath live infrastructure where speed, simplicity and minimal surface disruption are critical.
With the sustainable solution of pipe ramming, we offer a cost-effective and efficient alternative to traditional trenching methods that minimises ground disturbance, environmental damage and high installation costs. The method involves driving steel pipes through the ground using percussive force, allowing rapid installation without the need for continuous excavation or spoil handling at the face.
Using our highly skilled tunnelling team and extensive experience, we deliver the installation of large-diameter steel pipes, making pipe ramming an ideal solution for utility, highway, rail and river crossings up to 80 m in length. The technique is particularly advantageous where ground conditions are granular or cohesive and where groundwater management or settlement control would otherwise add complexity to open-cut works.
Pipe ramming offers significant programme and logistics benefits. The relatively compact launch and reception requirements reduce site footprint, simplify access arrangements and minimise disruption to surrounding assets and communities. This makes it especially effective in constrained corridors, live transport environments and environmentally sensitive locations.
Our engineering-led approach ensures that pipe ramming is deployed where it offers genuine value. We assess ground conditions, pipe diameter and wall thickness, drive length, vibration sensitivity and asset proximity to confirm suitability and manage risk. Where required, pipe ramming can be integrated with follow-on excavation or lining works, providing flexibility in overall scheme design.
By combining practical trenchless innovation with experienced delivery, we provide pipe ramming solutions that are safe, economical and environmentally responsible, delivering reliable underground crossings with minimal disruption and maximum efficiency.
With the sustainable solution of pipe ramming, we offer a cost-effective and efficient alternative to traditional trenching methods that minimises ground disturbance, environmental damage and high installation costs.
Using our highly-skilled tunnelling team and extensive experience, we provide the installation of large-diameter steel pipes – ideal for utility, highway, rail and river crossings up to 80m in length.
Hand and mechanical excavation
Hand and mechanical excavation
We retain and actively invest in traditional hand-mined construction techniques, providing a specialist capability that remains critical where modern mechanised methods are not suitable. These methods include handworks and squareworks for tunnel construction, and timber shaft sinking, and are particularly effective in confined, sensitive or operational environments where new works must connect to existing assets with minimal disturbance.
With more than 800 skilled operatives ready to take on a challenge, we offer hand excavation solutions for situations where access, geometry, vibration limits or asset sensitivity prevent the use of TBMs, SCL or other trenchless plant. These techniques allow precise, incremental excavation with continuous control of ground behaviour, making them ideally suited to live infrastructure interfaces.
Handworks and squareworks tunnelling provide exceptional flexibility for short drives, enlargements, junctions and break-ins to existing tunnels or chambers. By progressing excavation in small, controlled stages with immediate support, we are able to manage settlement, vibration and structural interaction risks with a level of precision that is impossible to achieve using mechanised systems. This makes the approach particularly valuable around operational railways, highways, utilities and legacy underground assets.
Timber shaft sinking remains a proven and reliable method for constructing access shafts in challenging ground or constrained locations. The technique allows excavation and support to be advanced together, providing stability in variable or water-bearing ground while maintaining a small surface footprint. Timbered shafts are especially effective where shafts must be formed adjacent to existing structures or within restricted urban sites.
As the wider industry continues to lose these specialist skills, we are actively preserving and growing this capability within our workforce. Through targeted training, mentoring and succession planning, we ensure that traditional mining techniques remain a viable and dependable option for projects where engineering judgement, craftsmanship and experience are paramount.
By combining traditional hand-mined methods with modern engineering oversight and assurance, we deliver safe, low-impact and highly controlled underground works, enabling critical connections between new and existing infrastructure while maintaining the integrity and operation of surrounding assets
Pipe Jacking
Joseph Gallagher Ltd’s pipe jacking service is a trenchless tunnelling method used to install or repair underground pipelines by pushing pipes through the ground with hydraulic jacks, avoiding the need for open excavation.
This approach allows pipelines to be constructed beneath roads, railways, and rivers with minimal surface disruption, offering high accuracy, improved safety, and environmental benefits compared to traditional digging methods
