From tunnel alignments cutting through complex geological strata to underground mining operations, every project presents unique challenges related to geology, technology, and construction safety. In such environments, efficiency is not achieved through a single product; rather, it requires the seamless integration of materials, equipment, and technical expertise.
Adopting a comprehensive approach, MC Underground (MCU)—a specialized division for underground construction within the German-based MC-Bauchemie Group—develops tailored chemical solutions and technologies for mechanized tunneling (using TBMs), conventional tunneling, and mining. The company supports projects throughout the entire process, from the tunnel face to the final completed structure.
Challenges in Tunnelling and Mining Operations
Tunnelling and mining are among the most technically demanding fields of underground construction. Projects are often carried out under complex geological conditions, where variations in ground formations, groundwater pressure, temperature and soil and rock properties can directly affect construction safety, project schedules and operational efficiency.
From mixed ground conditions and highly adhesive clay to hard rock formations, fault zones and areas subjected to high groundwater pressure, each environment requires appropriate engineering approaches and specialised materials. Challenges such as soil adhesion, abrasion, vibration and water ingress can also significantly affect equipment performance and structural stability.
At the same time, underground construction projects face increasingly stringent requirements for cost efficiency, construction schedules, safety and sustainability. In urban environments, controlling ground settlement and minimising impacts on adjacent structures are particularly critical. Meanwhile, expectations for longer service life, reduced maintenance requirements and compliance with environmental regulations continue to rise.
Addressing these challenges requires more than high-quality individual materials. Project success also depends on the effective integration and coordination of technical solutions throughout the entire construction process.
MC Underground – An Integrated Systems Approach to Underground Construction
Each field presents its own technical challenges and operational requirements. While Tunnel Boring Machine (TBM) tunnelling demands precise control to maintain continuous operations, conventional tunnelling requires greater flexibility to adapt to changing geological and construction conditions. In underground mining, safety, process reliability and shorter excavation cycles are among the highest priorities.
What these three fields share is the need for integrated, well-coordinated solutions covering ground conditions, excavation operations, ground support, waterproofing and long-term structural protection.
This is the approach embraced by MC Underground (MCU): combining expertise in construction chemicals with advanced application technologies and technical support to address the practical challenges of underground construction.
In mechanised tunnelling, the stability of the entire excavation process directly influences project schedules, costs and construction safety. In particular, controlling excavated ground properties, maintaining face pressure and ensuring the reliable operation of TBM support systems are critical technical requirements.
MCU provides integrated chemical and technological solutions for both Earth Pressure Balance Tunnel Boring Machines (EPB TBMs) and Slurry Tunnel Boring Machines (Slurry TBMs), while also supporting essential operations such as machine sealing, annulus grouting and precast tunnel segment production.
Solutions for EPB TBMs
In EPB tunnelling, excavated soil is used directly to generate the pressure required to support the tunnel face. The material within the excavation chamber must therefore exhibit suitable properties in terms of workability, plasticity, deformability and pressure transmission.
However, different ground conditions present distinct challenges. Sandy and gravelly soils can make it difficult to maintain the required soil consistency, while highly adhesive clay may accumulate on the cutterhead, cutting tools and material conveying systems.
To address these challenges, MCU develops specialised TBM soil conditioning solutions based on foaming agents, polymers and performance-enhancing additives. These systems improve the properties of excavated material, facilitate muck transport, support the control of excavation chamber conditions and help maintain efficient TBM operations.
Key technologies include:
MC-RheoSand®: Foam and polymer-based solutions designed to improve the consistency, workability and water retention properties of excavated soil.
MC-RheoClay®: Specialised solutions for clay-rich ground conditions, supporting adhesion control while helping reduce water consumption.
MC-StartupFoam®: A specialised solution for TBM start-up operations, helping establish suitable material conditions and support stable machine operation during the initial excavation phase.
Solutions for Slurry TBMs
Unlike EPB TBMs, which use excavated soil to balance face pressure, Slurry TBMs use a supporting slurry, typically bentonite-based, to maintain tunnel face stability. During operation, slurry properties and the efficiency of excavated material separation play a critical role in maintaining face pressure, transporting excavated material and ensuring excavation performance.
MCU provides specialised additives and flocculation systems that help maintain suitable slurry properties, reduce adhesion-related issues and improve separation efficiency, even in ground conditions with high clay content.
By selecting solutions tailored to the geological conditions and operational requirements of each project, MCU aims to optimise excavation performance while managing technical risks throughout Slurry TBM operations.
Integrated Support Solutions for Both EPB and Slurry TBMs
Beyond the excavation process itself, TBM performance also depends on effective machine sealing, annulus grouting and the quality of precast tunnel lining segments.
MCU provides specialised lubricating and sealing greases for the main bearing and tail shield, helping prevent water and fine particles from entering critical machine components.
These solutions are complemented by suitable pumping technologies that ensure the reliable conveyance and delivery of highly viscous materials, such as tail sealant greases.
Following the installation of precast tunnel lining segments, the annular gap between the outer surface of the segmental lining and the surrounding ground must be filled with a suitable grouting system.
This process plays an important role in controlling ground settlement, filling voids and facilitating the early, uniform transfer of loads from the surrounding ground to the tunnel lining.
MCU offers one-component (1K) and two-component (2K) backfill grouting systems, as well as specialised cement-free and permeable grouting solutions to meet different project requirements.
The quality of precast tunnel lining segments directly influences the structural load-bearing capacity, watertightness and long-term durability of the tunnel lining.
MCU provides concrete admixtures, reinforcing fibres and specialised curing systems for precast segment production, designed to meet demanding requirements for concrete strength, resistance to TBM jacking forces, long-term durability and surface finish quality.
The effective integration of these solutions helps support stable and efficient excavation, segment installation and tunnel lining construction.
Unlike mechanised TBM tunnelling, conventional tunnelling often requires greater flexibility in adapting excavation methods to actual geological conditions. From sequential excavation in soft ground to drill-and-blast methods in hard rock, ground characteristics and construction quality directly influence ground stability and structural safety.
In underground mining, in addition to ground support and stabilisation requirements, excavation productivity, rapid re-entry into working areas and process reliability are particularly important.
MCU develops specialised material solutions and application technologies to meet these requirements, ranging from shotcrete and rock anchoring systems to grouting and ground reinforcement materials.
Shotcrete and Ground Support Systems
Shotcrete plays a vital role in conventional tunnelling and underground mining by providing ground support, stabilising exposed rock and soil surfaces after excavation, and contributing to the long-term durability of underground structures.
To meet diverse technical requirements, MCU offers a comprehensive portfolio of solutions, including concrete admixtures, reinforcing fibres, hydration control systems and alkali-free shotcrete accelerators. These solutions help control both early-age and ultimate strength development in shotcrete, supporting safe excavation cycles while reducing material rebound during application.
The appropriate combination of admixtures and application technologies also enables shotcrete properties to be tailored to specific excavation methods, geological conditions and spraying equipment.
Rock Anchoring Grouts and Backfilling
Alongside shotcrete, rock anchoring and backfilling systems play an important role in reinforcing the surrounding ground and maintaining the stability of underground structures.
MCU provides rock bolting grouts, backfilling admixtures and specialised products designed to improve the workability, stability and application performance of grout mixtures.
One of the key solutions is MC-Montan Injekt CG Boost, an admixture developed to enhance the properties of conventional cement-based injection grouts. The product helps produce highly stable grout mixtures with optimised flow properties and controlled expansion, contributing to the reduction of undesirable volume changes. These characteristics are particularly important for grouting, anchoring and void-filling applications, helping establish stable bonding conditions and improve the reliability of ground reinforcement systems.
MC-Montan Shotcrete HA-X – High Early Strength for Shorter Excavation Cycles
In underground mining, the rate of shotcrete strength development significantly influences how quickly personnel and equipment can safely re-enter working areas and proceed with subsequent operations.
Particularly where short excavation cycles are essential, shotcrete must not only meet safety requirements but also deliver reliable early strength development.
MC-Montan Shotcrete HA-X is a range of alkali-free shotcrete accelerators developed by MCU to meet these demanding requirements.
With good storage stability, low dosage requirements and reliable early strength development even at low temperatures, the product range helps enhance process reliability while simplifying transportation, storage and on-site handling.
By supporting the development of the required early strength, this solution aims to optimise excavation cycles and reduce waiting times before subsequent construction activities, while meeting project-specific safety and technical requirements.
In underground construction and tunnelling projects, not all ground conditions and potential challenges can be accurately predicted during the design phase.
Issues such as groundwater ingress, cracks, voids and unexpected changes in geological conditions may arise, affecting construction schedules, safety and structural integrity.
Therefore, in addition to solutions supporting excavation operations, MCU provides specialised material systems to address unforeseen on-site challenges, as well as long-term structural maintenance and protection requirements.
- Technical Injection Solutions
MCU offers specialised injection resin systems designed to control groundwater ingress, seal leaks, fill cracks and voids, and reinforce or stabilise soil and rock formations under suitable application conditions.
Expanding material systems are also available for joint sealing and treating areas susceptible to water ingress.
- Concrete Repair and Rehabilitation Solutions
For concrete structures affected by damage or deterioration, MCU draws on MC-Bauchemie’s comprehensive portfolio of specialised repair materials to help restore structural performance and maintain construction quality.
The portfolio includes concrete repair systems tailored to the technical requirements of underground structures, including materials that have undergone fire-resistance testing within their respective assessment scopes.
Tunnel Surface Protection Solutions
MCU also provides specialised concrete surface protection systems (OS – Surface Protection Systems) for tunnel structures, designed to reduce the impact of pollutants and aggressive substances on concrete surfaces.
These protective systems help preserve structural integrity, enhance long-term durability and reduce repair and maintenance requirements throughout the service life of underground structures.
A key strength of MCU’s approach lies in integrating specialised materials, application technologies and on-site technical support into a unified solution system, rather than addressing individual challenges in isolation.
Technologies Driving Cost Efficiency and Sustainability
In tunnelling and mining, sustainability goes beyond simply reducing material consumption. It also involves optimising the entire construction process, from material selection and operational efficiency to the long-term service life of underground structures.
MCU focuses on developing chemical solutions and application technologies that promote efficient resource utilisation, support environmental requirements and enhance overall project performance. This commitment is reflected in solutions such as foaming agents with suitable biodegradability characteristics, injection systems selected in accordance with groundwater protection requirements, and technologies incorporating cement-free or alkali-activated binders.
Improving construction efficiency is another important aspect of sustainable underground construction. When construction processes are effectively controlled, minimising operational interruptions, reducing shotcrete rebound, optimising admixture dosages and extending maintenance intervals can contribute to cost savings, lower resource consumption and reduced emissions associated with construction activities.
Cost efficiency therefore depends not only on material prices but also on the reliability of the entire construction process. Every optimised operation, every avoided interruption and every solution appropriately selected for its application conditions contributes to improving overall project performance. This is the value of an integrated systems approach: combining technical performance, cost optimisation and environmental responsibility within a long-term development strategy.
MC Underground (MCU) – Your Global Partner for Underground Construction Solutions
MC Underground (MCU) is a specialised business unit of MC-Bauchemie, Germany, a globally recognised construction chemicals group with over 60 years of experience, a presence in more than 50 countries, and a workforce of over 3,500 employees worldwide.
MCU provides specialised chemical solutions and advanced technologies tailored to the specific requirements of tunnelling and mining projects.
Combining global technical expertise, practical industry knowledge and an integrated systems approach, MCU delivers reliable, efficient solutions designed to meet the demanding conditions of underground construction projects worldwide.
In Vietnam, MC-BIFI Bauchemie represents MC Underground, bringing together international expertise, advanced technologies and local implementation capabilities to deliver comprehensive, innovative solutions for tunnelling and underground construction projects.
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MC-Bauchemie bundles underground expertise in new MC Underground (MCU) business unit
