'Automated Reconstruction, Execution and Update of Digital Twins for Tunnel Structures' is the title of a guest lecture that Prof. Jelena Ninić will give at 2:30 PM on 27 November 2026.

Guests are welcome to attend her lecture.

Abstract:
Tunnels are critical infrastructure assets whose safe operation depends on regular inspection, yet current practice still relies largely on periodic manual patrols in which inspectors visually identify cracks, seepage, spalling and deformations and record them by hand. This process is time-consuming, labour-intensive and strongly dependent on individual experience. Digital Twins (DTs) offer a route to transform it, but their value depends on how efficiently raw field data can be turned into semantically rich, analysable models, and how reliably those models can be kept up to date over the life of the asset.

We propose a framework for the automated reconstruction, execution and periodic update of Digital Twins for tunnel structures, progressing across maturity levels from descriptive and reflective towards predictive twins. Starting from mobile or terrestrial laser scanning point clouds and images, SAM4TUN, built on the Segment Anything Model, performs training-free instance segmentation of tunnel lining components, from which geometric parameters are extracted and a BIM-based digital model is reconstructed automatically. Surface damage is then detected using zero- and few-shot large vision models. A SAM-based panoptic segmentation approach with multi-inference post-processing handles ultra-high-resolution panoramic tunnel images, while DOWSER, a DINO-based one-shot network, recognises water seepage from a single annotated image and around two minutes of development effort with 95% accuracy compared to a fully supervised models. The detected damage is mapped onto the digital model and passed to DEM or IGA analysis to simulate damage propagation in the lining, linking observed condition to structural performance.

The talk will also report on an ongoing project with Network Rail on automating defect detection in operational railway tunnels, including results on real inspection datasets and a web-based interface for integration with existing GIS-based asset management workflows. Together, these developments point towards remote, consistent and data-driven tunnel inspection, in which the digital twin is refreshed with every new survey and supports evidence-based maintenance decisions.

On Friday, 27 November 2026, at 9:00 AM Yaman Zendaki will give his PhD defense, titled 'Simulation-Supported Decision Making in Mechanized Tunneling: From TBM Steering to Urban Tunnel Alignment Design'.

Abstract:
Urban tunnels are increasingly built with tunnel boring machines (TBMs) that pass close beneath existing buildings, and the resulting ground movements can damage these structures. Two decisions largely determine this risk: the tunnel alignment in the design stage and the operation of the machine during construction. Detailed three-dimensional simulations can predict the consequences of these decisions, but a single simulation takes many hours. In the design stage, this limits the analysis to a few selected alignments. During construction, simulation results are not available within the short time in which the machine must be adjusted to unexpected ground conditions.

This dissertation develops a framework that makes high-fidelity tunneling simulations usable for decisions in both stages. It builds on a finite cell model of the mechanized tunneling process, in which soil layers, tunnel alignments and buildings share one structured mesh, so new geometries require no remeshing. The model is generated automatically from project data, including borehole records, building footprints and construction process data, and validated with monitoring data from a tunnel project in The Hague, the Netherlands.
Surrogate models based on proper orthogonal decomposition and radial basis functions (POD-RBF) then replace the full simulation, predicting settlements, lining forces and building damage within seconds instead of hours.

These components are combined into two applications. In the design stage, an interactive tool evaluates thousands of tunnel alignments along a 1.4 km urban corridor with more than 2,500 buildings. It uses domain decomposition and multi-objective optimization to balance construction cost, curve radius and building safety. In the construction stage, the SMART assistant supports the selection of TBM operational parameters when unexpected ground conditions are encountered, predicting around two million result values per scenario in a few seconds.

The results show that detailed numerical simulation can move beyond isolated pre-construction studies and directly support interactive decisions throughout a tunnel project.

A new open access paper entitled 'Adaptive mesh reorientation for concrete fracture analysis using cohesive zone models with interface elements' written by Koussay Daadouch, Vladislav Gudžulić, Günther Meschke is now available online.
It was published in the journal 'Computer Methods in Applied Mechanics and Engineering' by Elsevier.

Abstract:
Cohesive zone models with interface elements are widely used for simulating crack initiation and propagation, but their practical reliability is often limited by mesh bias: cracks can only propagate along predefined elements’ boundaries, so predicted crack paths and global response may be strongly controlled by mesh orientation. In badly oriented automatically generated meshes, this can make physically admissible crack trajectories inaccessible and lead to inaccurate fracture patterns and artificial stiffness.
This work introduces a novel adaptive mesh reorientation method to overcome this limitation while preserving the core strengths of interface-element formulations: discrete crack representation, natural crack initiation, branching, coalescence, and closure. No crack tracking and no predefined crack initiation locations are required. After each load step, mesh nodes are relocated so that intact interface elements progressively align with locally preferred fracture directions derived from the current stress state. The update is posed as an auxiliary constrained discrete variational problem for the mesh displacements and solved in a staggered step after mechanical equilibrium.
The approach is applicable in two and three dimensions. Its performance is demonstrated on established concrete fracture benchmarks, including heterogeneous mesoscale cases. The method can be integrated into finite element frameworks that allow for custom element or solver operations. Nine benchmarks have been considered, including complex geometries, material heterogeneity, and large-scale structural fracture simulations. The results consistently show improved crack-path prediction, reduced mesh sensitivity, and capture of crack initiation in the interior of the domain.

'Simulation-based machine learning for real-time reliability analysis of different tunnel shapes under quasi-static loading' is the title of a paper written by Ba Trung Cao, Van Vi Pham, Ngoc Anh Do, Hoang Giang Bui, Chi Thanh Nguyen, Tai Tien Nguyen, Manh Tan Do and Daniel Dias. It was published in the European Journal of Environmental and Civil Engineering, Volume 30, Issue 1, by Taylor & Francis.

Abstract:
Circular and rectangular tunnels are commonly studied under seismic loading, while sub-rectangular tunnels have recently been adopted in practice. This study uses the Finite Difference Method (FDM) to analyse six tunnel shapes under seismic conditions by quasi-static analysis displacement-based methods, considering both soil and tunnel parameters. The resulting data on internal force distribution in the linings form a valuable dataset for machine learning applications. An ensemble machine learning (ML) framework, Extreme Gradient Boosting (XGBoost), is proposed as an efficient alternative to the computationally demanding FDM for tunnel design optimisation. XGBoost achieves rapid predictions with strong agreement to FDM results. Feature importance analysis identifies key design variables affecting performance. Additionally, full-field predictions of internal forces in six tunnel shapes demonstrate the model’s high efficiency. Considering uncertainties in seismic and soil characteristics, a reliability-based framework using Monte Carlo Simulation estimates tunnel lining reliability. Finally, a user-friendly application has been developed to predict internal force extremes and distributions and perform real-time reliability analysis, offering a practical tool for preliminary tunnel design under seismic loading.

The first 50 people can get a free online copy via this link:

'A coupled finite element formulation for chemo-mechano-thermodynamical contact and its application to bonding and debonding' is an open access article by Prof. Sauer. The paper has been published in Computer Methods in Applied Mechanics and Engineering (Elsevier).

Abstract:
This work presents a finite element formulation for coupled chemo-mechano-thermodynamical large deformation contact. The formulation is based on the contact theory of Sauer et al. (2022) that contains six coupled (but separate) fields: the deformation and temperature of the two contacting bodies, as well as an interfacial bonding field and interfacial temperature. The latter is governed by the chemical and mechanical energy dissipation at the interface. Here the focus is placed on the evolution of bonding and debonding, and how it is coupled to the mechanical and thermal contact state. Several elementary models are proposed for this based on a quadratic contact potential. The resulting contact formulation becomes very general and versatile, which is illustrated by several challenging examples. They include pressure- and gap-dependent bonding, exothermic bonding reactions, thermal hardening and thermal expansion, as well as simultaneous bonding and debonding. They are based on a monolithic finite element implementation using classical and isogeometric shape functions together with implicit time integration. Its full linearization, required for the Newton–Raphson solution method, is also provided for the six-field problem, as well as for several of its simplifications. If bonding sites are material points, the bonding variable can be condensed-out locally.

Read the full article here: