Guest Post by Bentley Systems – Author: Oana Crisan, Senior Product Marketing Manager, Bentley Systems

Going underground is a seemingly simple approach to the increasing pressure for infrastructure in our fast-growing societies—but it is far from simple. Tunneling can carry enormous costs per kilometer, with impressive (but pricey) tunnel boring machines engineered and driven with great precision but operating in highly uncertain subsurface conditions. Any breakdown in collaboration between the multiple disciplines in the project can result in poor decision-making and critical risks to project delivery and the profitability of the project.

But successful construction is just the start of the journey. Underground infrastructure is a long-term investment—just look at the London Underground, with the metropolitan line opened over 150 years ago but now spans lines with 270 stations, carrying 4 million passengers daily. We need to set forth with ongoing operation and expansion in mind by bringing a multidiscipline digital twin approach from the outset.

As we respond to the challenge to do more with less, we can lean on the advantages offered by digital solutions to increase agility while accelerating manual and repetitive tasks. We can provide engineers with more time to analyze potential errors and create alternatives for optimum design, safety, and performance prior to construction, and carry this into the operational phases.

The Persistent Paradox of Underground Engineering

Tunnel projects have long faced a uniquely challenging reality: engineers must design complex structures to last generations while having only fragmented glimpses of the environment those structures will inhabit. The ground doesn’t yield its secrets easily.

Pat McLarin, who leads the strategy for civil infrastructure at Seequent, the Bentley Subsurface Company, puts it neatly: “There is a degree of uncertainty that comes with understanding the subsurface because the measured data—which originates from a wide variety of different sources—is never enough.”

This isn’t just an engineering curiosity—it’s a critical business issue. Ground-related problems account for the vast majority of cost overruns and delays in major tunnel projects worldwide.

But what if we could tip the odds in our favor?

Beyond Digital Models: The Twin Paradigm Shift

The term “digital twin” has been circulating in engineering circles for years, but its application to the subsurface realm represents a new mindset. Our best understanding of the underground isn’t a static model of what lies beneath—it’s a living, dynamic representation that evolves as new data emerges and as our understanding deepens.

Think of it as the difference between a photograph and a conversation around a common view. A photograph captures a moment in time from a single perspective. A conversation around a shared visualization evolves, incorporates new information, and builds understanding over time. Critically, it’s the shared visual models that enable this productive conversation—without them, different disciplines tend to talk past each other, missing the common understanding essential for collaboration. Traditional approaches to tunnel design have relied heavily on “photographs,” static geological models that represent our best understanding at a particular moment. These models have served us well, but they’ve also reinforced disciplinary silos between geologists, geotechnical engineers, structural designers, and civil engineering.

The multidiscipline digital approach initiates a conversation between these disciplines, between data and interpretation, between what we know and what we’re learning. It’s this conversation that marks the true paradigm shift.

Italy’s Underground Renaissance: A Transformative Implementation

To understand the practical impact of this shift, consider Italy’s aging tunnel network—a vast 2,500-kilometer underground arterial system built primarily in the 1960s and 1970s. These tunnels, critical to the country’s transportation infrastructure, face mounting challenges from decades of use and evolving safety standards.

Tecne Systra took on this challenge by reimagining how tunnel assessment and rehabilitation could work in a digital age. Their approach didn’t simply digitize existing processes—it fundamentally transformed them.

Their workflow begins not with disciplinary handoffs but with integrated data collection. Borehole TV cameras, flat jacks, core drilling, and other investigative tools feed into a unified digital environment where geologists, engineers, and designers work from the same evolving understanding of subsurface conditions.

The results are impressive: modeling time reduced by 25%, project delivery accelerated by 21.5%, interpretation of survey data improved by 30%, and clash detection time cut by 30%.

But beyond these metrics lies a more significant transformation: the integration of survey data into a continuous digital thread that extends from initial investigation through design, construction, and into the operational life of these tunnels.

Ana Emiliano dos Reis, who leads BIM implementation at Tecne Systra, noted how this approach changed their fundamental relationship with subsurface data: “Going digital transformed how we integrate and evaluate survey data, giving us entirely new capabilities to support design decisions.”

The invisible benefits – While cost and time savings make compelling headlines, the most profound benefits of digital twins may be those that never appear in project reports because they represent problems avoided rather than problems solved.

From Unknown Unknowns to Known Uncertainties

Traditional approaches to ground risk management have relied heavily on contractual mechanisms to allocate risk. Interdisciplinary collaboration offers something more valuable: the conversion of “unknown unknowns” into “known uncertainties.”

This distinction matters enormously. When project teams can visualize areas of geological complexity or uncertainty, they can make targeted investments in additional investigation rather than applying broad risk premiums. They can develop focused mitigation strategies rather than generalized contingencies.

As McLarin observes, “The digital twin can indicate areas of expected bad ground or where the ground conditions are unclear in the context of an engineering design.” This contextual understanding transforms how teams approach risk—not as something to be contractually transferred but as something to be collaboratively managed.

Sustainability Beyond Buzzwords

The environmental impact of tunnel construction extends far beyond the immediate project footprint. Material extraction, processing, transportation, and disposal create significant carbon footprints. The ability to optimize excavation and material reuse represents a substantial but often overlooked sustainability opportunity.

When engineers can simulate ground behavior with greater fidelity, they can design more efficient support systems, optimize excavation profiles, and develop targeted ground improvement strategies. Each refinement reduces material requirements and energy consumption.

“If we can optimize the amount of earth we move and the reuse of material, then we can be more sustainable,” McLarin notes. This isn’t sustainability as a marketing tagline—it’s sustainability through precision engineering.

Collective Intelligence Amplification

Perhaps the most powerful benefit of a digital twin is the least quantifiable: the ability to enhance collective intelligence across project teams and stakeholders. When geologists, geotechnical engineers, tunnel designers, and construction specialists share a common digital environment, something remarkable happens. Disciplinary boundaries begin to blur. Questions become more sophisticated. Insights emerge from unexpected connections.

“When everyone can really understand what’s going on in the subsurface, that leads to better decision making,” McLarin observes. This shared understanding transforms not just what teams decide but how they make decisions—with more inputs, broader perspectives, and deeper consideration of interdependencies.

Integrated Tunnel Design: Connecting Subsurface Data to Engineering Reality

The implementation of digital twins isn’t simply about adopting new software tools. It requires developing a new “grammar” for how different disciplines communicate and collaborate. This grammar consists of several key elements:

Continuous Data Integration

Rather than periodic data transfers between disciplines, digital twins require continuous integration of new information. Borehole logs, geophysical surveys, tunnel convergence measurements, and other data sources flow into a common environment where they immediately influence the collective understanding.[PM1]  This continuity is enhanced through solutions like Bentley’s OpenGround geotechnical extension, which seamlessly integrates subsurface data with civil design applications like OpenRoads, OpenRail, OpenBridge, and OpenTunnel. The extension allows geotechnical data to be directly imported and visualized in plan, 3D, profile, and cross-section views, eliminating data silos and ensuring that the latest subsurface information is immediately available to all stakeholders.

This continuity eliminates the “stale data” problem that has affected traditional workflows, where decisions might be made based on outdated information simply because the latest findings haven’t been processed and shared.

Visual Thinking at Scale

Humans are inherently visual thinkers, yet much of subsurface engineering has historically relied on numerical tables, charts, and written reports. Digital twins harness our visual cognition to understand complex three-dimensional relationships and patterns that might be missed in tabular data. When project leaders and stakeholders can literally see how geological formations interact with tunnel alignments or how settlement zones might affect existing structures, they grasp implications more quickly and make more informed decisions.

Dynamic Scenarios Rather Than Static Designs

Traditional design processes produce a series of increasingly refined static designs—conceptual, preliminary, detailed. Modern digital approaches enable a more dynamic approach, where teams can rapidly evaluate multiple scenarios and understand their implications across disciplines. This shift from “design documentation” to “design exploration” represents a fundamental change in engineering methodology. It’s not about documenting a single solution more efficiently, it’s about exploring a wider solution space more effectively.

From Handoffs to Continuous Collaboration

Perhaps most importantly, collaborative digital approaches transform the relationship between project phases and disciplines. Rather than sequential handoffs where responsibility transfers from one team to another, they enable continuous collaboration where insights flow in multiple directions.

Geologists inform geotechnical engineers about formation characteristics. Construction specialists provide feedback on excavation techniques that influence structural designs. Operators contribute insights about maintenance requirements that shape initial designs.

Current Challenges and Frontier Opportunities

Despite their transformative potential, these collaborative approaches face several significant challenges that must be addressed before they can become standard practice:

The Data Management Burden

The 2023 Geoprofessionals Data Management report revealed that geotechnical professionals spend approximately 20% of their time—one full day each week—simply managing data. This administrative burden reduces the time available for actual engineering analysis and interpretation.

Streamlining data workflows remains a critical priority. The ultimate goal must be systems that handle routine data processing automatically, freeing engineers to focus on exceptions, anomalies, and insights that require human judgment.

The Uncertainty Communication Challenge

While geotechnical engineers may have developed sophisticated methods for quantifying and managing uncertainty, communicating this uncertainty to other stakeholders remains difficult. Digital twins need visualization techniques that can effectively represent confidence levels, alternative interpretations, and ranges of possible outcomes. This isn’t simply a technical challenge—it’s a matter of developing a common framework for dealing with uncertainty that works across disciplines and stakeholder groups. The International Association of Engineering Geologists‘ guidelines [PM2] [PM3] [PM4] for geological engineering models represent an important step forward, providing a rigorous framework developing and applying geological engineering models critical relationship between conceptual, observational and analytical models.

The Interoperability Imperative

Despite significant progress, file compatibility and data translation issues remain obstacles for many organizations. These technical barriers reinforce organizational silos and limit the potential for true collaboration. Integration that allows the insights of one group to be used by another without breaking chain of custody or compromising traceability and data lineage is essential to success.

Progress requires not just technical solutions, but also industry alignment around common standards and protocols, plus open BIM standards have yet to be fully extended to tunneling.[PM5] 

The Future of Underground Innovation

The upcoming World Tunnel Congress in May will bring together the global tunneling community to explore innovations reshaping the industry. Bentley and Seequent will showcase their latest advances through several technical presentations and a dedicated booth where visitors can experience these connected workflows firsthand. This gathering represents an ideal opportunity to see how the gap between geological modeling and infrastructure engineering is being bridged through purpose-built solutions that address complex underground challenges.

Looking ahead, several emerging trends promise to further accelerate the evolution of digital collaboration in tunnel engineering:

AI-enhanced Interpretation

Machine learning algorithms are increasingly capable of identifying patterns in geotechnical data that might be missed by human analysts. These algorithms don’t replace engineering judgment, they also amplify it by filtering noise, highlighting anomalies, and suggesting correlations that warrant closer investigation.

Sensor Fusion and Real-time Monitoring

Advances in sensor technology and data transmission are enabling more comprehensive monitoring during both construction and operation. These systems provide continuous feedback that refines our understanding of ground behavior and structural performance.

Extended Reality for Enhanced Visualization

Virtual and augmented reality technologies are creating new ways to interact with subsurface data. These immersive visualization tools make complex spatial relationships more intuitive and accessible to diverse stakeholders.

Beyond Technology: The Human Dimension

While technological capabilities continue to advance, the most significant challenges, and opportunities, in implementing multidiscipline digital approaches are human rather than technical. Organizations that recognize this reality will be best positioned to realize the full potential of these transformative technologies.

Successful implementation requires attention to several key human dimensions:

Skill Development across Disciplines

Engineers, geologists, and construction specialists need opportunities to develop skills that span traditional disciplinary boundaries. These “T-shaped professionals” combine depth in their primary discipline with breadth across adjacent fields.

Collaborative Leadership

Project leaders must create environments where multidisciplinary teams can collaborate effectively. This requires not just technological infrastructure, but also cultural norms that encourage questioning, knowledge sharing, and collective problem-solving.

Client Education and Engagement

Project owners and operators need to understand the value proposition of digital twins—not as technological novelties, but as business tools that reduce risk, enhance predictability, and create lifecycle value.

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Conclusion: A New Underground Reality

The subsurface world has always been characterized by uncertainty and complexity. What’s changing isn’t the ground beneath our feet, but rather our ability to understand it, visualize it, and work with it more effectively.

Digital twins represent more than a technological advance; they embody a fundamental shift in how we approach underground infrastructure. By exposing uncertainty, enhancing collaboration, and supporting lifecycle management, they make tunnels safer, more sustainable, and more efficient.

In an era of increasing infrastructure demands and resource constraints, these connected digital workflows aren’t just nice to have. They’re essential to building the resilient underground networks that will serve communities for generations to come.

The ground may not yield its secrets easily, but with advanced collaborative approaches, we’re asking better questions—and getting better answers—than ever before.

Guest Post by Bentley Systems

Author: Oana Crisan, Senior Product Marketing Manager, Bentley Systems

Author: Oana Crisan is a senior product marketing manager focused on civil design engineering solutions and applications at Bentley Systems. She is responsible for the development of go-to market strategies, creating consistent messaging and content, and enabling sales to achieve new business growth. She holds a BA in business information systems from Dublin Business School, Ireland, and a BA in international relations and European studies from Petru Maior University, Târgu Mureș, Romania.

She can be reached at oana.crisan@bentley.com.