•Predictive models for tunnel convergence were proposed based on ANN and MARS.•The models were developed using field data from Daguan tunnels, China.•The proposed models exhibit excellent prediction ...capability.•ANN shows lightly higher accuracy but MARS is more interpretable.
Determining the tunnel convergence is an indispensable task in tunneling, especially when adopting the New Austrian Tunneling Method. The interpretation of the monitoring allows adjusting the construction methods in order to achieve more effective tunneling conditions and to avoid problems like rock collapse, trapping and jamming of boring machine, delay of the project or even geological disasters. In this research, a model capable of predicting the diameter convergence of a high-speed railway tunnel in weak rock was established based on two approaches: Multivariate Adaptive Regression Spline (MARS) and Artificial Neural Network (ANN). A tunnel construction project located in Hunan province (China) was used as case study. The input parameters included the class index of the surrounding rock mass, angle of internal friction, cohesion, Young’s modulus, rock density, tunnel overburden, distance between the monitoring station and the tunnel heading face and the elapsed monitoring time. The performance of the models was evaluated by comparing the predicted convergence to the measured data using several performance indices. Overall, the results showed high accuracy of the model predictability of tunnel convergence with MARS showing a light lesser accuracy. However, MARS was more flexible and computationally efficient. It is concluded that MARS can constitute a reliable alternative to ANN in modeling nonlinear geo-engineering problem such as the tunnel convergence.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The documentation of the tunneling process is a crucial task of every tunnel construction project. It provides evidence of the work performed and thus, serves as a basis for invoicing and for several ...further analyses. Therefore, continuous digitalisation of this documentation is essential. For this purpose, we provide a digital Tunneling Information Management System (TIMS), which is a prototypically implemented software tool for replacing the still common paper‐based documentation process of tunneling projects using the New Austrian Tunneling Method (NATM). The data model presented here defines the data structures managed by this tool. Based on this, the software architecture and the implementation of TIMS is shown.
Das Tunneling Information Management System – Ein Werkzeug zur Dokumentation von Tunnelbauprozessen in NÖT Projekten
Die Dokumentation des Tunnelbaus ist eine wichtige Aufgabe bei jedem Tunnelbauprojekt. Diese dient dem Nachweis der geleisteten Arbeit und damit als Grundlage für die Rechnungslegung und für verschiedene weitere Auswertungen. Eine durchgängige Digitalisierung dieser Dokumentation ist daher unerlässlich. Zu diesem Zweck stellen wir ein digitales Tunneling Information Management System (TIMS) zur Verfügung. Dabei handelt es sich um ein prototypisch implementiertes Softwaretool, um den immer noch üblichen papierbasierten Dokumentationsprozess von Tunnnelbauprojekten mit Neuer Österreichischen Tunnelbaumethode (NÖT) zu ersetzen. Das vorgestellte Datenmodell definiert die von diesem Tool verwalteten Datenstrukturen. Darauf aufbauend wird die Softwarearchitektur und die Implementierung von TIMS vorgestellt.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Autogenous shrinkage is the term for the bulk deformation of a closed, isothermal, cement-based material system not subjected to external forces Jensen OM, Freiesleben Hansen P. Autogenous ...deformation and RH-change in perspective. Cement and Concrete Research 2001;31:1859–65. It is associated with the internal volume reduction of the cement/water mixture in the course of the hydration process. The question arising from engineering practice is the magnitude of the autogenous deformations, increasing the compliance of concrete support structures and inducing tensile stresses which may lead to cracking of early-age concrete. In this paper, a multiscale model for cement-based materials focusing on the prediction of autogenous-shrinkage deformations is presented. In addition to the formulation of the underlying multiscale framework, including the identification of observation scales and the development of appropriate upscaling schemes, shrinkage experiments on cement pastes were conducted and used for the validation of the developed multiscale model. Finally, the multiscale model is used to determine the early-age elastic and shrinkage properties of shotcrete. These properties are employed in the context of hybrid analyses of shotcrete tunnel linings, providing access to the level of loading of the tunnel support structure during NATM tunneling.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The investment in tunneling shows an worldwide expansion trend. Reduction of risks, as part of the financial strategy of the stakeholders, has been the focus of several research studies. This paper ...aims to describe the construction risk prevention, in terms of occupational accidents and diseases, of the 2nd phase of the Marão Tunnel (Portugal) - the longest roadway tunnel in the Iberian Peninsula excavated with Sequential Method -with the particularity of the works being interrupted, leaving the tunnel only with primary lining for three years. The methodology is based in: 1) identification, by literature review, of most typical preventive measures and assessement of their applicability in the case study; 2) description of new preventive approaches. The paper will start with a history of work accidents, followed by the case study and, finally, it will delve into the preventive measures applied, as well as the new approaches, such as over-runs, falling blocks and risks associated with the suspension of works. Measures identified in literature were implemented and their validity was assessed. New approaches provided an safer and quickest way to work. This study is relevant to future tunnelling sites, since it is a good example of risk management using new approaches.
Recent studies have increasingly investigated construction methods for tunnel excavation because of growing underground space development. Although the New Austrian tunneling method (NATM)—a ...representative tunnel excavation method—can be applied to various ground conditions, as well as having good constructability and economic feasibility, it suffers from problems such as vibration and noise. By contrast, excavation using a tunnel boring machine (TBM)—a representative mechanized construction method—affords advantages such as stable excavation, minimized ground and environmental damage, noise, and vibration. However, it cannot be applied easily to various ground conditions, and it suffers from problems such as high construction costs and delays owing to equipment defects. Therefore, the simultaneous pilot tunnel excavation using the TBM—which affords advantages such as constructability, economic feasibility, and minimized noise and vibration—and rear enlargement blasting using NATM was investigated in this study. A protection shield was installed to minimize accidents occurring from equipment defects (a disadvantage of TBM) and analyze the decrease in the effect of NATM blasting, which depends on the use of the protection shield and the separation distance through 3D numerical analysis.
Mass movements are very common problems in the eastern Black Sea region of Turkey due to its climate conditions, geological, and geomorphological characteristics. High slope angle, weathering, dense ...rainfalls, and anthropogenic impacts are generally reported as the most important triggering factors in the region. Following the portal slope excavations in the entrance section of Cankurtaran tunnel, located in the region, where the highly weathered andesitic tuff crops out, a circular toe failure occurred. The main target of the present study is to investigate the causes and occurrence mechanism of this failure and to determine the feasible remedial measures against it using finite element method（FEM） in four stages. These stages are slope stability analyses for pre-and postexcavation cases, and remediation design assessments for slope and tunnel. The results of the FEM-SSR analyses indicated that the insufficient initial support design and weathering of the andesitic tuffs are the main factors that caused the portal failure. After installing a rock retaining wall with jet grout columns and reinforced slope benching applications, the factor of safety increased from 0.83 to 2.80. In addition toslope stability evaluation, the Rock Mass Rating（RMR）, Rock Mass Quality（Q） and New Austrian Tunneling Method（NATM） systems were also utilized as empirical methods to characterize the tunnel ground and to determine the tunnel support design. The performance of the suggested empirical support design, induced stress distributions and deformations were analyzed by means of numerical modelling. Finally, it was concluded that the recommended stabilization technique was essential for the dynamic long-term stability and prevents the effects of failure. Additionally, the FEM method gives useful and reasonably reliable results in evaluating the stability of cut slopes and tunnels excavated both in continuous and discontinuous rock masses.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
AbstractBased on an advanced micromechanics-based nonlinear creep model for shotcrete and thin shell kinematics, measured displacement data are first converted into in-plane stress fields throughout ...a shotcrete tunnel shell driven according to the New Austrian Tunneling Method (NATM). Subsequently, the partial differential equations for the local force equilibrium in the cylindrical coordinate directions are solved for out-of-plane shell stresses, inclusive of the tractions at the ground-shell interface. Results obtained for an NATM-tunnel driven through clayey ground at moderate depth show that the maximum shear tractions at the ground-shell interface may even exceed the maximum normal tractions (ground pressure). At the same time, even a young top heading tunnel shell may act as an arching thrust. The authors regard this method as a further step in the continously refined of interpretation of displacement measurements stemming from tunnel monitoring systems for the NATM, on a well-defined mechanical basis. This results in two structural models for top heading excavation stages, which might have the potential to support NATM predesign activities in the future.
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DOBA, FGGLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Estimation of tunnel diameter convergence is a very important issue for tunneling construction, especially when the new Austrian tunneling method (NATM) is adopted. For this purpose, a systematic ...convergence measurement is usually implemented to adjust the design during the whole construction, and consequently deadly hazards can be prevented. In this study, a new fuzzy model capable of predicting the diameter convergences of a high-speed railway tunnel was developed on the basis of adaptive neuro-fuzzy inference system (ANFIS) approach. The proposed model used more than 1 000 datasets collected from two different tunnels, i.e. Daguan tunnel No. 2 and Yaojia tunnel No. 1, which are part of a tunnel located in Hunan Province, China. Six Takagi-Sugeno fuzzy inference systems were constructed by using subtractive clustering method. The data obtained from Daguan tunnel No. 2 were used for model training, while the data from Yaojia tunnel No. 1 were employed to evaluate the performance of the model. The input parameters include surrounding rock masses (SRM) rating index, ground engineering conditions (GEC) rating index, tunnel overburden (H), rock density (ρ), distance between monitoring station and working face (D), and elapsed time (T). The model’s performance was assessed by the variance account for (VAF), root mean square error (RMSE), mean absolute percentage error (MAPE) as well as the coefficient of determination (R2) between measured and predicted data as recommended by many researchers. The results showed excellent prediction accuracy and it was suggested that the proposed model can be used to estimate the tunnel convergence and convergence velocity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Optimization of jet-grouted support in NATM tunnelling Pichler, Christian; Lackner, Roman; Martak, Lothar ...
International journal for numerical and analytical methods in geomechanics,
June ‐ July 2004, Volume:
28, Issue:
7-8
Journal Article, Conference Proceeding
Earth anchors inclusive solid bars (bolt, rebar) and stranded wire cables, have been extensively exercised in a wide range of geotechnical engineering. Shotcrete is also prevalent for the purpose to ...restrain rock exposures from excessive deforming and loosening. The relationships of meso-structure property are at the heart of the FEM towards the performance of reinforced hydraulic structures. Based on experimental studies, this chapter presents comprehensive studies inclusive explicit (distinct) approach and implicit (equivalent) approach of reinforcement components and joints. Either of them exhibits intrinsic advantages and disadvantages. The former uses special elements to individually discretize joints and reinforcement components to extract detailed behaviors of reinforced structures, whereas the latter elaborates an equivalent constitutive relation neglecting the exact positions of joints and reinforcement components to provide the overall structural response. One of the major advancements achieved in this chapter is that the localized shear deformation at the intersection points of bolts/shotcrete layers with joints is taken into account, which enables to describe the behaviors of bolt/shotcrete at the joint in much more detail even with implicit approach. The other important advancement is the consideration of the interface between equivalent bolt-grout material and host rock, which makes it possible to simulate the pull-out mechanism of bolt with explicit approach. In addition to a number of validation examples interspersed within the context, this chapter is closed with three engineering application cases (underground cavern, cut slope, dam foundation).
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FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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