La Directiva 2017/164/UE reducirá drásticamente los niveles de NO y NO2 en minería subterránea y construcción de túneles, existe preocupación con respecto a la viabilidad de los niveles propuestos y ...se estableció un período de transición que finaliza en agosto de 2023, está prevista una reevaluación de su aplicabilidad antes del final de este período. El estudio se realizó en un túnel de autopista de 2 km, sección de excavación de 102 m², método de excavación NATM, el túnel seleccionado es representativo del sistema de construcción de túneles en España. Este documento tiene como objetivo analizar los niveles de gas NO y NO2 durante la construcción del túnel y comparar los resultados con el nivel propuesto en la Directiva 2017/164/UE y los niveles vigentes. El informe concluye que se deben hacer esfuerzos para alcanzar los niveles de la Directiva en 2023. Se dan recomendaciones para alcanzar el nivel propuesto.
As the modernisation of the cities, railway road construction and modernisation of existing lines are demanded during the past decades more than before. Demand of short travel time is one the reasons ...that we redesign of existed railway roads and modernisation process. Tunnel construction is one the ways that we can shorten travel time in the existing railway roads. In this study, we introduced one of the commonly used tunnel construction methods, New Austrian Tunnelling Method (NATM), and some of important points of that method regarding tunnel excavation and bearing capacity of excavation support system. Furthermore, we gave some information about some tunnels which shortens the travel time and some tunnel project examples which are constructed with this method. The main purpose of construction of all these tunnels are to shorten the travel time of the existing railway line due to increasing on population and urbanization.
Abstract With recent technological advancements, tunnel boring machines (TBM) have developed and exhibited high performance in large diameters and weak ground conditions. Tunnels are crucial ...structures that significantly influence the timelines of highway and railway projects. Therefore, the construction of tunnels with TBMs becomes a preferred option. In this study, a comparative analysis between TBM and the New Austrian Tunneling Method (NATM) for tunnel construction is performed in the construction of the T1 tunnel with a diameter of 13 m, which is the longest tunnel in the Eşme‐Salihli section of Ankara‐İzmir High‐Speed Railway Project (Türkiye). The selection of TBM type, measures taken in problematic sections, and application issues of TBM are discussed. The impact of correct description of geological and geotechnical conditions on both selection and performance of TBM is presented. An earth pressure balanced type TBM is chosen for the construction of the T1 tunnel. Because of the additional engineering measures taken before excavation in problematic areas, the tunnel was completed with great success within the initially planned timeframe. From this point of view, this study is an important case and may contribute to worldwide tunneling literature.
Highlights Due to the increasing need for transportation, new high‐speed rail investments are also increasing. Due to the standards of railways, it is necessary to construct a large number of tunnels. The geological‐geotechnical properties and construction processes of the T1 tunnel, which is the fastest construction among the tunnel boring machines tunnels with a diameter of 13 m and larger, are presented as an important case study.
The T8 tunnel was constructed within the scope of the Ankara - Sivas High-Speed Railway project. The tunnel route is formed completely by very weak and weak lithological units. The overburden ...decreases to 10 m, and the highest overburden thickness reaches up to 60 m. The tunnel is large with a 150 m
2
excavation area and 14 m diameter. During the excavations in the section with an overburden thickness of 12 m, the supports failed, and the tunnel was completely collapsed. The purposes of the present study are to discuss the causes of the failure and engineering measures and to compare NATM and ADECO-RS methods with three-dimensional (3D) numerical analyses. Considering the mechanism of failure, extra engineering measures were proposed and the T8 tunnel was completed successfully. For the purpose of the study, a series of 3D numerical analyses were performed, and the results are discussed. The results obtained from the 3D numerical analyses showed that the ADECO-RS method yielded higher performance than the NATM method, for very weak and weak ground conditions (Category C).
This study aims to develop a system that improves operational efficiency by centrally managing the information obtained at each stage of the design, construction, and maintenance of mountain tunnels. ...In this study, the items required for mountain tunnels are examined in reference to building information modeling (BIM) that has been developed in the field of architecture. The basic information includes topography, geology, and support design information at the planning stage; observation, measurement, and analysis results during construction; and information on concrete lining deformation at the post-completion maintenance stage. In addition, the BIM/construction information modeling and management (CIM) practical application system is developed and applied to the site by considering the prediction of geological conditions in front of the tunnel face and the prediction of fault fracture zones and water inflow to ensure that the construction is carried out safely and as planned. Moreover, drawing the BIM/CIM in 3D is expected to promote information sharing and speed up decision making between clients and contractors, consequently leading to construction deadline conformance, construction cost reduction, and ensuring a safe and secure construction.
The face stability of the NATM tunnels (the New Austrian Tunneling Method) in undrained clays with a linearly increasing strength is numerically and analytically investigated by defining two types of ...the safety factors F in this paper. Based on the kinematic approach of the limit analysis, a continuous velocity field for an open-face tunnel is proposed. Moreover, the calculated solutions are compared with the results obtained from the numerical simulation and other existing literatures to validate its effectivity and superiority. The stability charts for different influence factors are also provided. Finally, an improved velocity field is presented, which provides a closer result to the real situation of the face collapse.
The topic of Building Information Modelling (BIM) adoption by public organizations has become a central subject of research, and a significant amount of BIM documents, guidelines, and standards have ...been created to meet different organizational purposes. Compared to the building industry, the application of BIM tools for tunnel project management is lagging far behind. This paper proposes a methodology for integrating BIM tools for conventional tunnelling. A fundamental distinction is made between the tunnel internal architectural domain and the external structural domain. For the former, BIM methodology can be applied similarly to the building industry. For the latter, it is suggested that a BIM model be built according to the essential information generated during tunnelling excavation. The proposed methodology was put to test for an actual tunneling project. A routine was established where the supervisor on behalf of the owner was responsible for gathering and reporting essential data in tabular form. Via REVIT's Application Programming Interface (API), a code was developed so that a BIM model was built and updated automatic to data insertion. Ultimately, the final BIM model allows managing up-to-date qualitative and quantitative information visually. Thus, human understanding and interpretation are enhanced for future uses, such as maintenance, future renovations and project post-analysis.
In the present work, important aspects of time-dependent nonlinear 3D finite element (FE) models for deep tunnel advance by the New Austrian Tunneling Method (NATM), characterized by repeated ...sequences of excavation, securing, and idle periods, are discussed on the example of a 3D finite element model of a stretch of the Brenner Base Tunnel, which is currently constructed between Austria and Italy. Nonlinear material models are utilized for representing the surrounding rock mass and the shotcrete shell. Based on the finite element model, strategies for the efficient implementation into a parallel distributed memory numerical code are proposed. They are essential to achieve reasonable computation times for numerical simulations of tunneling based on large 3D FE models. In particular, the implementation of the construction procedure, parallel computing and communication specific details, and efficient linear solvers for the global equation system within the incremental-iterative Newton–Raphson scheme are addressed. Furthermore, possible extensions of the material models for rock mass and shotcrete, used in the 3D FE model, are presented. They concern (i) a gradient-enhanced model for transversely isotropic rock and rock mass, taking into account hardening and softening behavior and (ii) the extension of the shotcrete model to nonlinear creep and damage due to creep. The possible benefits of the model extensions in numerical simulations of tunneling by the NATM are discussed.
NATM (new Austrian tunneling method) tunnel construction is unable to proceed under instable states of working face, so the stability of working face has been regarded as a key scientific issue. In ...this paper, a horizontal slice method based on the limit equilibrium analysis theory is employed to establish a model for the tunnel face stability. This model can overcome the shortcomings of the intersections between the slices and the bolts. In particular, an equivalent pressure coefficient is proposed to analyze the reinforcement of tunnel face bolts. Furthermore, based on the model, the influence of soil parameters and reinforcing strength of tunnel face bolt on the limit support forces are investigated. Moreover, based on the limit analysis upper bound theorem, the tunnel face failure model is also established, and the factors such as the soil parameters, the length and support force for unsupported section, tunnel depth and reinforcing strength of tunnel face bolt, are studied in order to investigate the limit support forces for tunnel faces. It is found that the tunnel face bolts can effectively increase the shearing strength of the front core soil. However, the strength of surrounding rocks cannot be enhanced too much because such an enhancement is not economical and effective. Finally, based on the comparison analysis, it is demonstrated that the variation trends of support force with the above relevant factors are almost the same in the proposed stability models, indicating the promising and wide applications of the proposed method.
Display omitted
•Artificial Ground Freezing technique to excavate a tunnel below the ground water table.•Freezing and thawing effects measured as displacement at the ground surface.•3D numerical ...analyses to simulate the excavation of the tunnel (NATM).
The paper is dedicated to the case history of a 13m wide, 17m high and 40m long service tunnel at Toledo Station, previously constructed in a deep open shaft and belonging to the Line 1 of the Napoli underground network. The existing Line 1 has been recently extended with a new stretch consisting of five new stations connected by twin rail tunnels for a total length of about 5km. Toledo Station main shaft is located by a side of the line and it is connected to the pedestrian platforms by the above mentioned large size service tunnel. The station is situated in the historical center of the city of Napoli, under a deeply urbanized area. In Fig. 1 a longitudinal section of the main shaft of the station and of the large service tunnel with the above and surrounding buildings is sketched. The focus of this paper is on the settlement caused by the tunnel excavation and on the use of the Artificial Ground Freezing (AGF) technique to allow the safe excavation of the large crown of the service tunnel, located about one half in a silty sand layer and one half in yellow tuff, well below the groundwater table.
PDF
