A hybrid finite element and surrogate modelling approach for simulation and monitoring supported TBM steering

The paper proposes a novel computational method for real-time simulation and monitoring-based predictions during the construction of machine-driven tunnels to support decisions concerning the steering of tunnel boring machines (TBMs). The proposed technique combines the capacity of a process-oriented 3D simulation model for mechanized tunnelling to accurately describe the complex geological and mechanical interactions of the tunnelling process with the computational efficiency of surrogate (or meta) models based on artificial neural networks. The process-oriented 3D simulation model with updated model parameters based on acquired monitoring data during the advancement process is used in combination with surrogate models to determine optimal tunnel machine-related parameters such that tunnelling-induced settlements are kept below a tolerated level within the forthcoming process steps. The performance of the proposed strategy is applied to the Wehrhahn-line metro project in Düsseldorf, Germany and compared with a recently developed approach for real-time steering of TBMs, in which only surrogate models are used

Automating Virtualization of Machinery for enabling efficient Virtual Engineering Methods

Virtual engineering as a new working method in product development should make it much easier to validate the development progress and facilitate team communication. Work steps are brought forward and start with the virtual components instead of real ones. To validate mechanical and electrical CAD as well as programming, automated virtualization systems should create the virtual twin of the machine at the push of a button. For this purpose, generic intelligence is added to enable complex interactive virtual models that can be used for training, monitoring and many other applications. Advanced applications are for example training and support applications, especially in combination with augmented reality and remote collaboration. We propose a system that combines virtual reality, virtual engineering and artificial intelligence methods for the product development process. Geometry analysis algorithms are used to process mechanical CAD data and thus, for example, to automatically parameterize kinematic simulations. In combination with electrical CAD data and the simulations of electric circuits as well as the original machine program allow simulating the behavior of the machine and the user interaction with it. This article will describe the virtualization method in detail and present various use-cases in special machine construction. It will also propose a novel method to use causal discovery in complex machine simulations

A simulation-based software to support the real-time operational parameters selection of tunnel boring machines

With the fact that the main operational parameters of the construction process in mechanized tunneling are currently selected based on monitoring data and engineering experience without exploiting the advantages of computer methods, the focus of this work is to develop a simulation-based real-time assistant system to support the selection of operational parameters. The choice of an appropriate set of these parameters (i.e., the face support pressure, the grouting pressure, and the advance speed) during the operation of tunnel boring machines (TBM) is determined by evaluating different tunneling-induced soil-structure interactions such as the surface settlement, the associated risks on existing structures and the tunnel lining behavior. To evaluate soil-structure behavior, an advanced process-oriented numerical simulation model based on the finite cell method is utilized. To enable the real-time prediction capability of the simulation model for a practical application during the advancement of TBMs, surrogate models based on the Proper Orthogonal Decomposition and Radial Basis Functions (POD-RBF) are adopted. The proposed approach is demonstrated through several synthetic numerical examples inspired by the data of real tunnel projects. The developed methods are integrated into a user-friendly application called SMART to serve as a support platform for tunnel engineers at construction sites. Corresponding to each user adjustment of the input parameters, i.e., each TBM driving scenario, approximately two million outputs of soil-structure interactions are quickly predicted and visualized in seconds, which can provide the site engineers with a rough estimation of the impacts of the chosen scenario on structural responses of the tunnel and above ground structures

Feasibility Study of a Continuous Borer-Bolter in an Underground Potash Mine

Potash mining in Saskatchewan is most commonly done using one of two underground dry mining techniques: A variation of room and pillar mining, and stress relief mining. The potash ore that is mined has a large areal extent, is located at great depths, and is typically flat lying. However, some pockets in the ore body vary from the general geology, and are called anomalous. These areas can result in reduced stability from what would normally be found in the typical geological conditions. Potash mines install rock bolts in anomalous ground conditions to counter this. This is currently done using two different machines and results in a lot of down time for the mining operation. It has been theorized that by combining the two machines into one, time can be saved from the current process and result in increased stability of the mine back. This study pertains to the feasibility of attaching a bolting system to the back of a continuous boring machine for excavating anomalous ground conditions in underground potash mines. Three parts of this are examined: an estimate of the time saved by changing bolting methods, the change in mine roof stability due to the different bolting method, and the feasibility of crafting a machine that can fit in the confined space required. Bolting procedures are examined using individual task rates and projected for the proposed bolting methods. The change in stability that results from changing the bolting procedure is analyzed using finite element analysis. Finally, a concept machine is devised to show the ability to put such a bolting machine in the confined spaced available, and therefore showing the possibility of implementation. The geometric constraints, determined by a theoretical system, were used to create several feasible processes for installing bolts from the boring machine. This resulted in four potential variations in the process with regards to both the potential saved time and the stability of the tunnel. It was found that the potential for time savings were very large, with up to 72% of the current bolt process time being saved in some situations. It was found that the largest part of the mining process in poor ground conditions is spent on the installation of bolts, and therefore the most time was saved by methods capable of bolt installation while the boring machine was in motion. Based on modelled stress metrics in areas requiring support, the current support measures appear more effective than the proposed bolting procedure. The analyzed stress metrics were still improved when compared to an unbolted ground scenario; Similar values of simulated curvature and displacement were found in the tunnel back at lower disseminated clay heights when partially bolted than were observed when the simulation was unbolted. This study shows the borer mounted bolter can be considered an advantageous mining method for efficiency purposes in poor ground conditions and could potentially be suitable in some geological conditions, but likely should not be used in all anomalous ground scenarios

MODELISATION 3D DU CREUSEMENT DE TUNNEL PAR TUNNELIER A FRONT PRESSURISE VALIDATION SUR LE METRO DE SHANGHAI SHIELD TUNNELLING VALIDATION OF A COMPLETE 3D NUMERICAL SIMULATION ON THE YANGTZE RIVER TUNNEL, SHANGHAI

La réalisation de tunnels à faible profondeur en site urbain nécessite une évaluation préalable des effets du creusement sur les ouvrages existants. Dans le cas du creusement par tunnelier à front pressurisé, le phasage des travaux est un problème d’interaction sol/structure hautement tridimensionnel et les différentes opérations réalisées par le tunnelier rendent très complexe une modélisation numérique complète du problème et donc l’évaluation des mouvements induits. Une procédure de simulation tridimensionnelle, utilisant le code en différences finies Flac-3D (Fast Lagrangian Analysis of Continua en 3 Dimensions), prenant en compte de manière explicite les principales sources de mouvements dans le massif encaissant est proposée. Elle est illustrée dans le cas particulier du métro de Shanghai, creusé à l’aide du plus grand bouclier jamais utilisé et pour lequel des données expérimentales existent, les sols rencontrés étant saturés et caractérisés par une faible résistance. La confrontation des résultats de simulation numérique avec les mesures in-situ montre que la procédure de simulation 3D proposée est pertinente, en particulier dans la représentation adoptée pour les différentes opérations réalisées par le tunnelier (excavation, soutènement du front de taille, avancement, pose du revêtement, injection du vide annulaire, …).The excavation of shallow tunnels in urban areas requires a previous evaluation of their effects on the existing constructions. In the case of shield tunnel boring machines, the different achieved operations are very complex to represent in a complete numerical simulation. Therefore the assessment of the tunneling-induced soil movements is difficult. In the case of shield tunnel boring machines, the different achieved operations is a highly three-dimensional problem of soil/structure interaction and are very complex to represent in a complete numerical simulation. Therefore the assessment of the tunnelling-induced soil movements is difficult. A three-dimensional simulation procedure, using finite differences code Flac-3D (Fast Lagrangian Analysis of Continua in 3 Dimensions), taking into account in an explicit manner the main sources of movements in the soil mass is proposed. It is illustrated in the particular case of the Yangtze River Tunnel of Shanghai for which experimental data are available and where the crossed soils are saturated and characterised by weak shear strength. The comparison of the numerical simulation results with the in-situ measurements shows that the 3D procedure of simulation proposed is relevant, in particular in the adopted representation for the different operations achieved by the tunnel boring machine (excavation, confining pressure, advancement, installation of the tunnel lining, grouting of the annular void, …)

3D numerical analysis of tunnelling effects on a multi-storey building: the case of Line 9 EPB tunnelling in Barcelona

Juntament amb el desenvolupament de les infraestructures en zones urbanes, la necessitat de construcció de túnels augmenta. Aquestes excavacions subterrànies provoquen moviments en el terreny que poden estar associats amb danys en estructures pròximes al traçat. Tot i la importància del fenomen d'interacció sòl-estructura, les deformacions dels edificis porticats no s'han estudiat exhaustivament i hi ha enfocaments de disseny limitats per avaluar possibles riscos. Aquesta dissertació presenta un model tridimensional d'elements finits de la interacció túnel-sòl-edifici per al cas Llave de Oro, documentat durant la construcció de la Línia 9 del Metro de Barcelona. A causa d’importants moviments produïts en el terreny per la construcció del túnel, diversos elements dels edificis monitoritzats van resultar danyats; amb fissures situades principalment a les zones adjacents a la junta de dilatació entre dos blocs del mateix edifici. En el model numèric es realitza la simulació de l'excavació del túnel, modelitzant l'edifici mitjançant una estructura de pòrtic semirígid amb juntes de dilatació. Els resultats numèrics s'avaluen tenint en compte els moviments observats in situ. L'estudi confirma la importància de la modelització de juntes de dilatació i el seu potencial per a produir esquerdes localitzades en edificis relativament rígids.Junto con el desarrollo de las infraestructuras en zonas urbanas, la necesidad de construcción de túneles aumenta. Estas excavaciones subterráneas provocan movimientos en el terreno que pueden estar asociados con daños en estructuras próximas al trazado. A pesar de la importancia del fenómeno de interacción suelo-estructura, las deformaciones de los edificios porticados no se han estudiado exhaustivamente y existen enfoques de diseño limitados para evaluar posibles riesgos. Esta disertación presenta un modelo tridimensional de elementos finitos de la interacción túnel-suelo-edificio para el caso Llave de Oro, documentado durante la construcción de la Línea 9 del Metro de Barcelona. Debido a importantes movimientos del terreno causados por la construcción del túnel, varios elementos de los edificios monitoreados resultaron dañados; con fisuras ubicadas principalmente en las zonas adyacentes a la junta de dilatación entre dos bloques del mismo edificio. En el modelo numérico se realiza la simulación de la excavación del túnel, modelizando el edificio mediante una estructura de pórtico semirrígido con juntas de dilatación. Los resultados numéricos se evalúan teniendo en cuenta los movimientos observados in situ. El estudio confirma la importancia de la modelización de juntas de dilatación y su potencial para causar grietas localizadas en edificios relativamente rígidos.Because of the currently growing infrastructure system in urban areas, an increasing number of underground tunnels are needed. Generally, underground excavations, such as tunnelling, cause surface soil movements and can be associated with structural damage. Despite the importance of the soil-structure interaction, the deformations of framed buildings have not been extensively studied and there are limited design approaches for their risk assessment. This dissertation presents a three-dimensional finite element model of a tunnel-soil-building interaction, giving insights into the building deformation mechanism for the Llave de Oro case history, documented during the construction of the Metro Line 9 Barcelona. Due to significant ground movements caused by tunnelling, several elements of the monitored buildings were damaged; with cracks mostly located in the areas adjacent to the expansion joint between two blocks of the same building. In the numerical model, the tunnel excavation is simulated, and the multi-storey building is modelled with a semi-rigid frame structure. The effect of expansion joints is evaluated through a parametric study. Results obtained from the numerical model are reviewed in consideration of available monitoring measurements, confirming the importance of modelling expansion joints and their potential for leading to localised cracking within relatively stiff buildings

Structural Analysis of Tunnel using FEA

Tunnels are typically built for transportation, such as roads, railways, or canals, but they can also be used for other purposes, such as mining, sewerage, or water supply. Tunnels allow us to travel safely and efficiently through difficult terrain, and they provide us with access to essential resources such as water and energy. The objective of current research is to evaluate the structural characteristics of tunnel structure under geo-mechanical loading conditions. The structural analysis of tunnel is conducted using techniques of FEA. The CAD modelling and FEA simulation of tunnel is conducted using ANSYS simulation package. The shear stress, normal stress and deformation data are generated. From the generated data, the critical regions are identified and the lateral zone of tunnel is one of them. This region is likely to induce damage in the form of crack

From Exploratory Tunnel to Base Tunnel: Hard Rock TBM Performance Prediction by Means of a Stochastic Approach

AbstractTunnel boring machine (TBM) performance prediction is often a critical issue in the early stage of a tunnelling project, mainly due to the unpredictable nature of some important factors affecting the machine performance. In this regard, deterministic approaches are normally employed, providing results in terms of average values expected for the TBM performance. Stochastic approaches would offer improvement over deterministic methods, taking into account the parameter variability; however, their use is limited, since the level of information required is often not available. In this study, the data provided by the excavation of the Maddalena exploratory tunnel were used to predict the net and overall TBM performance for a 2.96 km section of the Mont Cenis base tunnel by using a stochastic approach. The preliminary design of the TBM cutterhead was carried out. A prediction model based on field penetration index, machine operating level and utilization factor was adopted. The variability of the parameters involved was analysed. A procedure to take into account the correlation between the input variables was described. The probability of occurrence of the outcomes was evaluated, and the total excavation time expected for the tunnel section analysed was calculated

From Exploratory Tunnel to Base Tunnel: Hard Rock {TBM} Performance Prediction by Means of a Stochastic Approach

Tunnel boring machine (TBM) performance prediction is often a critical issue in the early stage of a tunnelling project, mainly due to the unpredictable nature of some important factors affecting the machine performance. In this regard, deterministic approaches are normally employed, providing results in terms of average values expected for the TBM performance. Stochastic approaches would offer improvement over deterministic methods, taking into account the parameter variability; however, their use is limited, since the level of information required is often not available. In this study, the data provided by the excavation of the Maddalena exploratory tunnel were used to predict the net and overall TBM performance for a 2.96 km section of the Mont Cenis base tunnel by using a stochastic approach. The preliminary design of the TBM cutterhead was carried out. A prediction model based on field penetration index, machine operating level and utilization factor was adopted. The variability of the parameters involved was analysed. A procedure to take into account the correlation between the input variables was described. The probability of occurrence of the outcomes was evaluated, and the total excavation time expected for the tunnel section analysed was calculated