Sika: your trusted partner to overcome challenges
Modern tunnel construction is very complex and faces a lot of challenges such as:
OPTIMIZING COSTS
The true cost of a tunnel is measured in decades. Owners require durable, low-maintenance structures, while contractors need solutions that minimize project expense and downtime. We optimize the total lifecycle cost with high-performance technologies and local supply from our over 100-country network with more than 300 production sites—ensuring cost control from excavation through a lifetime of operation.
TECHNICAL COMPLIANCE
Standards for watertightness, safety, and structural integrity are strict. Geographical conditions vary. Compliance demands certified products, reliable quality, and precise application. We provide proven technologies and expert support to ensure your project meets all specifications and achieves guaranteed long-term performance from day one.
SUPPLY CHAIN
Project schedules cannot tolerate delays. Contractors need on-time, local supply. With production in over 100 countries, we ensure material availability and short lead times. Our local logistics and expertise keep your project moving and mitigate schedule risk.
Sika provides a complete range of advanced construction solutions covering the entire tunnel lifecycle, from excavation to long-term operation. Our portfolio includes concrete and spray concrete admixtures, TBM technologies, waterproofing systems, injection and bolting systems, structural and fire protection fibers, repair and protection solutions, dust sealing, rail fixing, and digital concrete monitoring tools. These integrated systems are designed to support safe construction, durable performance, and efficient project delivery even in the most demanding geological environments.
Innovation has been at the core of Sika since 1910, when our first waterproofing solutions were used in the first Gotthard Rail Tunnel. Today, our global research and development centers continuously advance tunneling technologies for all phases of tunnel projects.
With more than a century of tunneling experience, worldwideproduction and R&D centers, and expert teams close to constructionsites, Sika is a proven and trusted partner for tunnel projects. Wecombine high-quality products and systems, deep technical know-how,and on-site support to help deliver successful tunnel projects—safely,efficiently, and with lasting performance.
Global Tunnel Construction Market
Approximately
86 billion
Euros are spent per year in tunnel and underground construction worldwide.¹
In 2022, a new record was established in tunnel construction. A total of
1,275
tunnel projects were under construction, amounting to around 185 billion CHF in investments.²
In 2022, the tunnelling industry has witnessed an average annual growth rate of approximately 10%, with a slight decrease in 2020 attributed to the COVID-19 pandemic. This growth rate is
2.5 times
higher than the growth rate observed in the global construction industry, reaffirming the robust and dynamic nature of the tunneling market.²
Global Tunnel Construction Output by Use¹
Total Excavated Tunnels in 2022 Worldwide²
¹Source: International Tunneling Association (ITA), Tunnel Market Survey 2016.
²Source: International Tunneling Association (ITA), Tunneling Market Analysis 2022.
An average of over
5,000 kilometers
of tunnels are constructed each year around the world.¹
10-Year Project Pipeline Worldwide (2022-2032)²
10-Year Project Pipeline per Region (2022-2032)²
Understand tunnel excavation methods and challenge
Tunneling projects today rely on a combination of advanced machinery, specialized materials, and precise engineering to create safe and durable underground structures.
Modern methods typically alternate between Tunnel Boring Machines (TBM) and conventional excavation, each selected according to geology, project scale, and operational constraints.
TBMs ensure continuous excavation with controlled face pressure, while conventional methods offer flexibility in complex or variable ground conditions.
Across both approaches, tunneling teams must manage challenges such as ground stability, water ingress, and heterogeneous geology. Chemical technologies play a crucial role in addressing these issues, enabling smoother excavation, optimizing material performance, and reducing operational risks.
Effective coordination between stakeholders is essential for maintaining progress and ensuring safety. As projects grow in complexity, integrated solutions become increasingly important to deliver tunnels that meet demanding standards for performance, durability, and sustainability.
Ground conditioning and excavation support solutions
Ground conditioning is essential for stable and efficient TBM excavation.
Foams, polymers, and additives are used to modify soil properties, improving workability, reducing permeability, and ensuring consistent face pressure.
These treatments help control challenging conditions such as clays, clogging, water table changes, soft grounds, or mixed geology, enabling smoother machine advance and reducing wear on tooling. Complementary excavation support—such as grouting and consolidation materials—maintains ground stability around the tunnel.
By tailoring conditioning and support systems to each geology, tunneling teams achieve safer operations, improved progress, and greater overall reliability.
Sprayed Concrete and Structural Lining Technologies
Sprayed concrete provides immediate ground support in tunneling, combining fast application with reliable early strength. Its performance depends on a balanced mix design, high‑quality materials, and admixtures such as accelerators, which enable rapid setting and improved safety during excavation.
Fibers are often added to increase toughness and crack control, ensuring a more resilient lining. As work progresses, the sprayed concrete primary lining must integrate smoothly with membranes, drainage systems, and the cast secondary lining. When designed and applied correctly, these systems create durable, robust tunnel structures with long‑term performance.
Waterproofing, Injections and Long-Term Durability
Effective water management is essential to protect tunnels and ensure long‑term performance.
Modern waterproofing systems—such as membranes, sealing strips, and drainage layers—create a continuous barrier that prevents water ingress and safeguards the structure.
When unexpected leaks or weak zones appear, injection resins and grouts provide rapid, targeted solutions to seal cracks, stabilize ground, and restore integrity.
The combination of robust waterproofing design, reliable materials, and precise installation is key to achieving durable, watertight tunnels that require minimal maintenance throughout their service life.
Safety, Efficiency and Digital Tools in Tunneling Operations
Safety and efficiency are essential in tunneling, where confined spaces and variable ground conditions require precise control. Chemical solutions enhance safety by stabilizing the excavation face, optimizing sprayed concrete performance, and reducing operational risks.
At the same time, digital tools are transforming daily workflows. Monitoring systems, quality‑control applications, and real‑time data platforms help teams track ground behavior, material consumption, and equipment status. These insights support faster decisions, minimize downtime, and improve coordination.
By combining advanced materials with digital technologies, tunneling operations become more predictable, productive, and consistently aligned with high safety standards.
Sustainability and Environmental Responsibility in Tunneling
Sustainable tunneling requires reducing environmental impact while maintaining high technical performance.
Modern chemical solutions support this goal by lowering CO₂ emissions, improving material efficiency, and extending the durability of tunnel linings.
Optimized ground conditioning, durable sprayed concrete, and long‑lasting waterproofing systems help minimize resource use and maintenance needs. Additionally, cleaner production processes, recycling strategies, and digital tools enhance transparency and reduce waste.
By integrating sustainable materials with responsible construction practices, tunneling projects can achieve safer operations, lower environmental footprints, and long‑term value for both infrastructure and the surrounding environment.
Concrete Solutions
Reliable and Durable Concrete – Key to Any Tunneling Project
Sika offers a fully integrated product range when it comes to concrete solutions for tunneling projects. For decades, Sika is involved on the most challenging and largest tunneling projects on the globe. From high durability concrete for efficient shaft linings to high strength road slabs, we offer the products that solve nearly every concrete challenge.
A set of mobile phone Applications for mix design, aggregates analisys and testing from Sika is also available.
Fast construction of safe and durable concrete structures is no longer a difficult task with Sika admixture technologies. Good pumpability, flow and compaction, followed by high early strength, then low permeability are the key characteristics for a good tunnel lining concrete.
High early strengths achieved with SikaRapid® technology
In order to reduce cycle times in underground operations, high early strengths are needed to ensure the lining can be demolded and precast elements can be moved, transported, and installed safely.
Extended workability times produced using Sika® ViscoCrete® & Sika® ViscoFlow® technology
In many situations, extending the workability time of the concrete is essential in tunneling applications, especially for pumped concrete where the transport distances and temperatures can be challenging factors in maintaining the required workability.
Good pumpability with SikaPump®
This pumping agent reduces friction resistance and wear in the pipes and in the pump, allowing increased volume output. Initially it is also used to produce a lubricant mix to coat the internal walls of the pipe with a high-fines layer and allow easy pumping, right from the start of the concreting operations.
In the hardened concrete, high mechanical properties are achieved by using SikaFiber® in the mix.
For many areas of structural concrete the resistance against percussive or striking impact, plus the toughness and flexural strength of the concrete itself, can be very significantly improved by the use of these Sika structural fibers.
High flow and workability with Sika® ViscoCrete® technology
An efficient way of quickly and easily placing concrete is the use of so-called self-compacting concrete. With the right Sika mix design, this is able to flow under its own weight, completely filling formwork and achieving full compaction without vibration, even around heavily congested reinforcement.
In tunnel segment production, high early strengths for rapid demolding, followed by the highest requirements with regards to performance and durability have to be fulfilled.
High early strengths achieved with SikaRapid® technology
In order to reduce cycle times in underground operations high early strengths are needed to ensure the elements can be demolded, moved or put under load as quickly as possible.
In hardened concrete, fire resistance can be achieved by using SikaFiber® in the mix.
For many applications of precast lining, fire resistance is provided by the use of synthetic microfibers. Sika microfibers have been tested and certified by independent bodies and are well referenced for such application in many projects around the world.
Sprayed Concrete
Speed Up Excavation Progress with Sika Shotcrete Technology
Achieving controlled strength, durability, and workability of Sprayed Concrete under difficult conditions, tight schedules, complex excavation sequences, and variable raw materials is a challenge.
Sika provides a comprehensive portfolio of admixtures for wet and dry Sprayed Concrete, including accelerators, superplasticizers, strength and workability enhancers, and durability-improving technologies. These solutions optimize concrete properties, enable rapid placement and strength gain, and deliver efficient, durable, high-quality tunnel structure.
A set of mobile phone Applications for mix design, aggregates analysis and Spray Concrete testing from Sika is also available.
Shotcrete is ideal for slope stabilization, especially when dealing with steep slopes and pit wall angles, in order to protect men and machinery in portals, galleries and on ramps.
Extended slump retention achieved with Sika® ViscoCrete® SC technology
Depending on the location and the complexity of the project, long haulage distances can require extended slump life of the concrete and in all manner of environmental conditions.
Rapid early strength development of the shotcrete is critical in order to enable short cycle times and ensure efficient rates of progress in tunneling.
High early strengths achieved using Sigunit® accelerators
Early setting of the shotcrete lining is critical in order to enable rapid underground development with short cycle times.
Sika provides support from pre-testing, right through with continuous on-site support, to the completion of operations, in order to realize ongoing efficiencies.
Pre-testing and raw material qualification
Sika has developed unique testing equipment known as “MiniShot” where local raw materials (e.g. different binders, accelerators, admixtures and additives, etc.) can all be quickly and reliably tested locally and efficiently to optimize shotcrete mix designs.
On site testing
After the pre-evaluation and mix selection of the shotcrete-system using the Sika MiniShot, the mix-design is tested under real conditions. The well trained Sika shotcrete teams will then implement the best cost performing solutions.
Trouble-free applications
Safe application, consistent speeds and uninterrupted spraying are critical factors for efficient in cycle shotcreting. This is achieved with Sika support to master the sprayed concrete operations with efficient equipment, mix designs, admixtures and skilled operators.
Waterproofing
Today, operators request a service life for underground structures of 100+ years.
Water ingress, hydrostatic pressure and aggressive ground conditions threaten structural durability, operational safety, and long-term maintenance costs.
Sika provides a comprehensive range of high- performance tunnel waterproofing systems, including SikaProof® fully bonded membranes, Sikaplan® WP loose-laid membrane and Sikalastic® liquid applied membrane systems, and complementary joint sealing and compartmentalization solutions with Sika® Waterbar, SikaFuko® injection hoses, and Sikadur®-Combiflex®. These integrated systems ensure reliable watertightness and long service life throughout the tunnel lifecycle.
Our waterproofing solutions include the systems for:
Rock and ground improvement and waterstoping
Unstable ground, water inflows, and fractured rock can slow excavation and impact long‑term tunnel performance.
SikaInject® resins and grouts provide fast, reliable ground consolidation, waterstopping, and structural stabilization. With deep penetration, controlled reaction times, and durable sealing performance, SikaInject® systems ensure effective water control, secure excavation, and lasting ground stability in demanding geological conditions.
Visit our webpage Injections for Ground Consolidation, Stabilization & Water-Stopping in Tunnels & Mines
Water inrush in tunnel structures represents a major hazard which hinders and delays excavation and drifting processes. Sika® PU-resin injection systems are a powerful solution to consolidate and stabilize the ground to prevent and/ or counter any water situations.
Cavity and void filling is used to consolidate the fractured strata and stabilize the ground to ensure a faster, safer development process. The fast-foaming Sika® Silicate based injection products have high expansion factors that can fill large cavities and voids in a safe way.
An efficient way to stabilize unconsolidated geological masses, fractured rock-strata or permeable soils is by using cementitious injection grouting materials. The SikaFix®-800 range provides excellent penetration and consolidation properties. These systems are based on specially-blended cements and micro-fine cements with Sika® admixtures that are used to adjust the viscosity and accelerate the material's setting and hardening.
Sika provides the full range of injection products and systems to fill, stabilize and consolidate the ground in different geological conditions. In situations where the ground has relatively low permeability, Sika® Acrylate based injection resins with their low viscosity, water-like consistency and penetration ability, will give superior performance over other chemical resins and cementitious grouting solutions.
The use of TBMs for tunnel construction in highly populated areas such as cities and urban areas is now well established. However, there is still an increased risk factor when dealing with fault zones and unconsolidated geology. Potential collapses and water inrush must all be avoided, as the potential cost of losing control during the tunneling process is very high. This risk can be safely mitigated by using Sika® pre-injection systems to consolidate and stabilize the ground ahead of the TBM.
Over-blasting represents a major issue when it comes to external ore-dilution in underground, high grade, narrow vein mines. This problem from frequent over-breaking of the roof and ribs of the excavated stope can be significantly reduced and controlled by stabilizing the production face with Sika® Silicate resin injection systems. The injection of the resin takes place before a new round is blasted.
Tunnel Boring Machines (TBM)
TBM excavation faces ground instability, water infiltration, cutterhead blockages, high wear, unexpected geology and clogging.
Sika Stabilizer TBM portfolio includes foaming agents and polymers for soil conditioning in EPB TBMs, foaming agents and polymers for rock and abrasive grounds , admixtures for backfill grouts, tail sealant greases, bentonites and polymers for slurry applications. These solutions enhance excavation efficiency, protect equipment, and ensure safe, continuous TBM excavation progress.
Concrete reinforcement and fire protection with fibers
Concrete reinforcement and fire protection with fibersPrimary rock support is often installed under variable conditions, making mesh placement unreliable and a dangerous health and safety risk.
Concrete mixed with SikaFiber® Force macro-synthetic fibers can be safely sprayed and delivers uniform reinforcement through the entire layer, omitting complicated mesh and no unsafe installation steps. With higher ductility and de-formation capacity than steel fibers, synthetic fibers keep the support performing even in challenging, squeezing ground. Synthetic fibers do not need to be covered by an additional fiber-free concrete layer before installing the waterproofing membrane.
Sika supplies also SikaFiber® micro PP fibres for the passive fire resistance.
Rail fixing for railways with reduced vibrations, noise and corrosion
Railways with Reduced Vibrations and Noise
Urban planners are obliged to expand local public transport and railway systems to cope with the rapid development of urban spaces. Long term durability, electrical resistance and low maintenance are essential. There is also an increase in requirements for reduced vibration and noise in the rail fastening system, making flexible, volume-compressible grout materials an effective solution.
Corrosion protection of underground metallic structures in railway & tramlines
In electrified rail and tram systems, stray electrical currents accelerate the corrosion of buried metallic structures such as pipelines, tanks, and foundations, posing long-term risks to infrastructure integrity and safety.
Sika® Icosit® Dielectric Membrane can effectively reduce current dispersion to prevent corrosion and interference, especially in dense urban areas with existing underground utilities.
Concrete repair and protection
Tunnels are exposed to moisture, chemical attack, mechanical wear, and aging - leading to structure damage and high maintenance costs.
Sika delivers comprehensive repair and protection systems including Sika MonoTop®, Sikagard® and SikaEmaco®. These solutions restore structural integrity, protect against corrosion and further deterioration, and extend tunnel durability, ensuring long-term safety, reliability, and total cost optimization.
Concrete Repair
Corrosion protection and bonding primers are used for bonding concrete repair mortars to existing cementitious or steel substrates and providing additional corrosion protection to reinforcement steel, especially in areas of low concrete cover and in the presence of chlorides. Exposed reinforcement steel bars should be properly prepared and protected with anti-corrosion slurry to further enhance the repair process.
Advantages:
- Ready to mix, easy to apply
- Adjustable consistency
- Active corrosion inhibitors for added protection
- Can be sprayed or manually applied
Repair mortars are specifically designed for restoring or replacing the original profile and function of the damaged concrete. They help to repair concrete defects, improve appearance, restore structural integrity, increase durability and extend the structure’s longevity.
Sika concrete repair mortars are suitable for restoration work, repair of spalling and damaged concrete in all types of structures including buildings, bridges, infrastructure and super-structures.
Advantages:
- Easy to mix and apply
- Pre-bagged for quality, just add water
- High mechanical properties
- Can be overcoated with Sika leveling mortars
- Can be sprayed or manually applied
- Pure cement-based, cementitious, polymer-modified and epoxy-based repair mortar materials available
When concrete needs to be coated or levelled, special mortars are necessary to fill the surface pores. Sika pore fillers and leveling mortars are thin layer renders designed to repair minor defects, such as repairing pores and honeycombed concrete.
Advantages
- Easy to mix and apply
- Pre-bagged for quality, just add water
- Can be overcoated with Sika protection coatings
- Can be sprayed or manually applied
The most common causes of steel reinforcement corrosion in concrete are caused by carbonation or chloride ingress with water. Understanding the root cause of steel corrosion determines the most effective repair and protection strategy.
Sika provides a full range of products to prevent further corrosion of steel reinforcement by properly protecting the concrete around it. Our corrosion management systems allow flexibility to select the most cost effective, suitable solutions for your project’s needs.
Concrete Protection
Active corrosion inhibitors
Passive corrosion inhibitors
Protective coatings
Cathodic protection
Sustainably Durable & Efficient
At Sika, we understand your commitment in the construction and maintenance of tunnels. Our solutions support sustainability at every stage of your tunnel's lifecycle, from responsible product selection and efficient application to long-lasting performance and end of life considerations.
Whether it is low carbon footprint and water saving concrete mix design or sustainable waterproofing, we help you achieve your goals by delivering quantified sustainable benefits through reliable and environmentally conscious solutions that comply with LEED, BREEAM, Green Building, and other relevant certifications. We carefully analyze all key sustainability aspects, including resource and material efficiency, waste reduction, durability, energy savings, health and safety, and CO2 emissions, to help you identify how to optimize your project sustainably at every step.
Below is an example how Sika Shotcrete support the sustainability concept - Impact of optimized vs non-optimized shotcrete Tunnel design based on a hypotheticaltunnel project with the following details: 1km tunnel of 10m diameter
Driving digitalization in tunnel construction and maintenance
Digital transformation is reshaping how tunnels are planned, built, and maintained. Sika supports this evolution with a comprehensive portfolio of advanced digital tools through SikaVision® — helping you monitor, collaborate, optimize, and predict key aspects of your construction or refurbishment projects.
Sika understands the complexity of decision-making across the project lifecycle and the importance of minimizing risk at every
stage. Our technologies and experts provide reliable data for your BIM models, enabling smarter collaboration and informed
decisions in your virtual design and planning environments.
By integrating SikaVision®, you can:
• Enhance efficiency – Streamline processes and accelerate project delivery
• Make informed decisions – Use reliable data for planning, design, and execution
• Maximize product performance – Get the most out of your Sika solutions
Explore our digital tools and see how SikaVision® brings the future of construction to your projects. >>
Sika’s Experts Provide Assistance to Benefit your Business
Local Contact
Contact a Sika expert near you for technical support and locally available products and systems.
Global Project Support
Sika’s Project Support Team provides in-depth consultative support for our full product range and represents a single point of contact into the extensive Sika network of experts. Please contact us to learn more or inquire specifically on your current project(s).
