Shaft Sinking
Caisson Sinking (Wet & Dry)
Caisson Sinking (Wet & Dry)
We are a leading specialist contractor in shaft sinking, recognised for the safe and reliable delivery of segmentally lined shafts in some of the most complex and constrained environments. Our capability spans the design and construction of shafts from 2 m to 25 m internal diameter, across all ground conditions, supported by decades of hands-on experience, specialist labour and owned plant and equipment.
We deliver segmental caisson shafts using a range of proven methodologies, selected to suit ground conditions, groundwater regime, access constraints and asset sensitivity. These include jacked wet caissons, jacked dry caissons, and dry underpinned caissons, providing flexibility to manage risk and maintain control in challenging subsurface conditions. Each approach allows excavation and support to be progressed in a controlled manner, ensuring stability, alignment and structural integrity throughout sinking operations.
Our teams are highly experienced in wet caisson sinking, where groundwater and soft or unstable strata require careful management of buoyancy, base stability and control of inflows. For dry conditions or where groundwater exclusion is achievable, dry jacked caissons provide an efficient and predictable solution. Where ground conditions allow, underpinned caisson techniques allow shafts to be formed safely with minimal movement and disturbance to surrounding assets.
Safety and sustainability are fundamental to our approach. We apply rigorous engineering controls, monitoring and sequencing to manage ground behaviour and asset interaction, while optimising materials and construction techniques to reduce waste and environmental impact. Concrete back-wrap options can be incorporated to enhance durability, watertightness and long-term performance where required.
By combining specialist labour, bespoke and proprietary plant, and a deep understanding of ground and structural behaviour, we deliver robust, precise and resilient shaft solutions. Our shaft sinking capability underpins complex tunnelling, utility, marine and infrastructure projects, providing safe access, long-term performance and confidence in the most demanding conditions.
Secant Piles/D-Wall
Secant Piles / D-Wall
We deliver shaft construction using secant pile and diaphragm wall techniques, providing robust, water-tight retaining solutions for shafts, basements and deep excavations in complex and constrained environments. These methods are particularly effective where ground and groundwater control, settlement management and asset protection are critical to successful delivery.
With safety as one of our core values, all works are completed to a standard we are proud of, using robust and innovative solutions underpinned by engineering-led planning and rigorous quality assurance. Through close collaboration with our trusted specialist supply chain, we offer the capability to design and construct complex piled shaft solutions with confidence across a wide range of ground conditions and geometries.
Our secant piled shafts are constructed using rotary bored or Continuous Flight Auger (CFA) techniques, selected to suit ground conditions, pile diameter, depth and site constraints. These methods allow precise pile installation, controlled overlap and reliable cut-off, forming continuous retaining walls capable of resisting earth and groundwater pressures. Where appropriate, diaphragm walling is employed to deliver high-stiffness, low-permeability shaft walls for larger diameters, deeper excavations or particularly demanding groundwater regimes.
Excavation within secant pile or diaphragm wall shafts is carefully sequenced, with temporary and/or permanent propping systems installed as excavation progresses. Propping arrangements are designed to manage wall deflections, maintain stability and protect adjacent assets, and may include internal steel frames, ring beams or slabs cast at intermediate levels. Where required, permanent structural elements are integrated into the temporary works strategy to optimise programme and reduce duplication.
Our integrated approach ensures seamless coordination between design, piling, excavation and propping activities. Early engagement with designers and stakeholders allows us to manage interfaces, programme constraints and risk from the outset, providing programme certainty and quality execution throughout delivery. Continuous monitoring and verification are applied to confirm performance against design assumptions and acceptance criteria.
By combining specialist piling techniques, experienced delivery teams and collaborative supply chain partnerships, we deliver safe, precise and resilient secant piled and diaphragm wall shafts, capable of supporting complex underground works in the most challenging environments.
Sheet and Frame Construction
Sheet and Frame Construction
We deliver sheet piling and framed shaft solutions as a proven, adaptable method of excavation support, particularly suited to constrained, sensitive and operational environments where flexibility, speed of installation and control of ground movement are critical.
Our experience and know-how within the team are efficiently utilised to construct conventional sheets and frames that provide reliable excavation support and enable safe progression of shaft works. Sheet piles can be pre-augered or driven, with the installation technique selected to suit ground conditions, depth requirements and proximity to existing assets.
Where works are undertaken adjacent to live infrastructure or within dense urban settings, we deploy silent and low-vibration piling methodologies to minimise noise, vibration and disturbance. This allows sheet piling solutions to be used effectively in locations where traditional driven methods would present unacceptable risk to third-party assets or stakeholders.
Excavation is carried out in a controlled sequence, with internal propping systems installed progressively to manage earth pressures and maintain stability. Depending on project requirements, we utilise proprietary modular propping systems for speed, repeatability and efficiency, or bespoke fabricated propping frames to accommodate complex geometries, restricted access or challenging interfaces. These systems are designed to integrate seamlessly with excavation sequencing and wider construction activities.
A key strength of our delivery model is our close working relationship with strategic supply chain partners, including specialist piling contractors, temporary works designers and fabricators. This collaborative approach allows early engagement on methodology selection, propping strategy and logistics planning, ensuring solutions are practical, buildable and aligned with programme and risk objectives.
Through the combination of experienced delivery teams, flexible piling techniques, robust propping solutions and trusted supply chain relationships, we provide safe, efficient and dependable sheet piling and framed shaft solutions that support successful underground and shaft construction across a wide range of site conditions.
Drill and Blast Shafts
Drill and Blast Shafts
We provide a specialist drill and blast shaft sinking and tunnelling capability across the UK and Middle East, delivering bespoke rock excavation solutions where traditional mechanised tunnelling methods are not suitable. This approach is particularly effective in hard rock formations, complex geometries and constrained environments where flexibility, precision and engineering control are paramount.
When mechanised tunnelling is not viable, we combine our extensive experience with the controlled use of explosives or gas-pressure blasting pyrotechnics to deliver safe, efficient and highly adaptable drill and blast solutions. These techniques allow excavation to be tailored precisely to ground conditions, shaft or tunnel geometry and interface requirements, making them ideal for shafts, caverns, enlargements and short tunnel drives in competent rock.
Successful execution is driven by carefully planned and rigorously implemented details. Our works are delivered by skilled and certified drillers, shotfirers and blast engineers, all trained in-house to maintain consistent standards of safety, quality and control. This in-house expertise enables us to manage the full blast process, from design through to execution, without reliance on third parties.
We develop complete, project-specific blast design packages, tailored to the geological conditions, excavation geometry and proximity of sensitive assets. Blast vibrations are predicted, analysed and monitored, allowing charge weights, timing and sequencing to be optimised to control vibration, air overpressure and flyrock. This approach ensures protection of nearby structures, live infrastructure and the surrounding environment, while maintaining productivity and cost efficiency.
Our capability spans urban and remote environments, including highly constrained sites in the UK and large-scale, technically demanding projects in the Middle East. We manage all aspects of explosives planning, procurement, storage and logistics, ensuring full compliance with regulatory requirements and seamless integration with programme and site operations.
By combining engineering-led blast design, specialist in-house skills and a strong focus on safety and environmental control, we deliver robust, precise and cost-effective drill and blast shaft sinking and tunnelling solutions. This capability provides our clients with confidence that even the most challenging rock excavation works can be executed safely, efficiently and with minimal impact on surrounding assets and operations.
Vertical Shaft Sinking Machine (VSM)
Vertical Shaft Sinking Machine (VSM)
As part of our shaft sinking capabilities, we offer the use of Vertical Shaft Sinking Machine (VSM) technology for the delivery of large-diameter, deep shafts in challenging ground conditions. VSM provides a highly controlled, mechanised solution where conventional shaft sinking methods would introduce increased risk, programme uncertainty or unacceptable surface impact.
The VSM’s modular plant design enables flexible site set-up, making it particularly well suited to inner-city locations and confined sites where access, logistics and footprint are constrained. Components can be assembled within restricted working areas while still delivering the robustness and capacity required for deep excavation. This versatility allows shafts to be constructed efficiently while maintaining tight control of line, level and ground behaviour.
VSM technology is especially effective in complex or variable ground conditions, including mixed strata and groundwater-affected environments. Excavation, spoil removal and lining installation are integrated into a single, continuous process, reducing exposure at the shaft base and improving safety compared to traditional sinking techniques. The method provides enhanced stability during excavation and enables predictable progress at depth.
We have recent high-profile experience in the UK using VSM on technically demanding infrastructure schemes, where the method has been selected to manage ground risk, protect adjacent assets and maintain programme certainty. These projects demonstrate the growing role of VSM as a preferred solution for modern, large-scale shaft construction in sensitive environments.
Our delivery is supported by specialist in-house labour, experienced supervision and owned or directly controlled plant and equipment, ensuring full integration of the VSM into the wider construction methodology. Early engineering input is used to define shaft geometry, lining strategy, interfaces and logistics, allowing the VSM approach to be optimised from the outset.
By combining mechanised precision, flexible site deployment and decades of shaft construction experience, we provide a safe, efficient and resilient VSM shaft sinking capability. This solution offers clients confidence in the delivery of large, deep shafts where ground conditions, location or programme demand the highest levels of control and assurance.
Shaft and Waterproofing and Lining
Shaft and Waterproofing and Lining
We deliver a fully integrated shaft waterproofing and lining capability, providing robust, durable and long-life solutions for shafts constructed in a wide range of ground and groundwater conditions. Our approach is engineering-led and construction-informed, ensuring that waterproofing and lining systems are selected, detailed and installed to suit shaft geometry, depth, construction methodology and long-term performance requirements.
Waterproofing Systems
Effective waterproofing is fundamental to shaft performance, operational safety and whole-life asset value. We provide both sheet membrane and spray-applied waterproofing systems, deployed either independently or in combination depending on risk profile and design intent.
Sheet membrane waterproofing is used where a proven, multi-layer barrier is required to manage groundwater pressure and ensure long-term durability. Installation is carefully coordinated with primary support systems with particular attention paid to laps, welds, penetrations, interfaces with drainage systems and transitions at base slabs and headings. Detailed quality assurance and inspection regimes are embedded throughout installation to ensure integrity prior to secondary lining.
Spray-applied waterproofing systems offer a highly effective alternative in shafts with complex geometry, tight tolerances or restricted access. These systems form a fully bonded, seamless barrier that reduces the risk of water tracking and simplifies detailing around openings, fixings and irregular profiles. Spray-applied systems also offer programme efficiencies by integrating more easily with sprayed or cast secondary linings.
Secondary Lining Solutions
We deliver a range of secondary lining options, selected to align with structural requirements, programme constraints and durability targets.
Spray-applied secondary linings provide a flexible and efficient solution where speed, adaptability and quality control are critical. These linings can deliver structural capacity, durability and finish in a single operation, with thickness controlled and verified using digital scanning and monitoring techniques. This approach is particularly effective in shafts with variable geometry or where access constraints limit conventional formwork.
Where cast in-situ linings are required, we utilise proprietary jump form shutter systems, enabling controlled, repetitive pours with consistent geometry and high-quality finishes. Jump forms are well suited to deep shafts constructed in stages, allowing lining installation to progress safely and efficiently while maintaining alignment and tolerance control.
For large-diameter or deep shafts where continuous construction is advantageous, we also deliver slip-formed concrete linings. Slip forming enables near-continuous placement of concrete, reducing the number of construction joints, improving durability and accelerating programme delivery. This technique is particularly effective where shaft geometry is regular and long, uninterrupted pours are feasible.
Across all waterproofing and lining systems, our teams manage reinforcement fixing, interface detailing, curing, inspection and verification, ensuring seamless integration between excavation support, waterproofing and permanent lining elements. Construction sequencing is carefully planned to manage groundwater risk, maintain access and ensure safe working at depth.
By combining multiple waterproofing technologies, flexible lining methodologies and specialist in-house expertise, we deliver shaft solutions that are watertight, structurally robust and designed for long-term performance. This integrated capability provides clients with confidence that shafts will perform reliably throughout their operational life, even in the most demanding underground and groundwater conditions.
Quality assurance
As part of our quality assurance, we provide comprehensive waterproofing for shafts and tunnels using membranes, linings, and sealant systems tailored to ground conditions and client requirements. This ensures long-term durability and protection against water ingress.