Austrian Tunneling Method Research Articles

Zayıf zeminlerde açılan büyük çaplı çift tüp tünellerde tünellerin birbirine olan etkisinin 3 boyutlu sayısal analizler ile incelenmesine bir örnek, Bolu Tüneli destek sistemlerinin değerlendirilmesi

Bolu Tüneli Ankara İstanbul Otoyolu üzerinde yer almaktadır. Bolu Tüneli proje çalışmalarına 1993 yılında başlanmış olup 2007 yılında trafiğe açılmıştır. 3 şeritli çift tünel olarak inşa edilmiştir. Tünel uzunlukları sağ tünel 2788 m sol tünel ise 2954 m’dir. Bolu Tüneli inşası sırasında 2 kez sel ve 2 kez depreme maruz kalmış ve tünelin Ankara girişinde yeralan Elmalık kesiminde 12 Kasım 1999 Düzce Depremi sonrası göçük yaşanmıştır. Bu göçük sonrasında tünel güzergahı değiştirilmiştir. Bolu Tüneli jeolojik olarak Kuzey Anadolu Fay Hattı ana kolu ile Düzce Fayı arasındaki tektonik bloktan geçmektedir. Tünelin İstanbul tarafı (Asarsuyu girişi) metakristalin temel kayaları içerisinde yer almakta iken Ankara tarafı (Elmalık girişi) sedimanter kayaçlar içerisinde bulınmaktadır. Tünel bu iki birimi Bakacak fayı ile kesilmektedir. Tünelde kazı aşamasında en büyük sorunların meydana geldiği Elmalık girişinde Elmalık fayı bulunmakta olup, tünelin bu bölümlerinde 1.2 m’ye varan deformasyonlar ile karşılaşılmıştır. Ayrıca Elmalık sağ tünelde fay geçişi sırasında 1996 yılında göçük meydana gelmiş, 12 Kasım 1999 Düzce Depreminde ise Elmalık sol tünel tamamen kapanarak göçük oluşmuştur. Yeni Avusturya Tünelcilik Yöntemi ile projelendirilen Bolu Tünellerinde yaşanan sorunlar ve geliştirilen destek sistemleri tünelcilik açısından çok değerli bilgiler içermektedir. Bu çalışma kapsamında Bolu Tünel destek sistemleri Flac3d programı ile 3 boyutlu olarak incelenmiş, iki tünelin birbirine olan etkisi, üst yarı, alt yarı ve invert kazılarında meydana gelen değişimler ortaya konmuştur.

Оперативный геодезический контроль деформаций призабойной зоны при инновационных технологиях проходки туннелей

Purpose: To consider the issue on performance of operational control of deformations of tunnel bottomhole zone with the use of ground-based laser scanning technology when tunneling with New Austrian tunneling method which is the most progressive one and feasible in economics terms for underground building construction by mining. The essence of this method is in that as a support for tunnel bottom-hole zone, a self-supporting shell made of sprayed concrete without traditional fastening method usage is applied that allows to save time for tunneling significantly, especially of those tunnels which have complex geometry and non-standard dimensions. At the same, the conceptual basis for this method is the necessity to identify operatively bottomhole zone soil mass deformations that’s justified by the need to provide job realization safety. Methods: As a major method for to determine tunnel bottomhole zone geospatial position it is proposed to consider ground-based laser scanning technology. Scanning result processing was implemented in specialized software package Leica Cyclone 3DR. Results: Existing experience of geodetic check of deformations in tunneling by New Austrian method is considered. Processing results for data on ground laser scanning of a tunnel separate fragment are presented, a tunnel mathematical three-dimensional model is obtained and assessment of deviations of tunnel actual surface from obtained theoretical one is fulfilled. Practical significance: The obtained threedimensional model can be further used for geodetic monitoring of deformations. Theoretical bases for estimation required accuracy for deformation characteristics definition are substantiated which are based on the transition from construction tolerances to average quadratic errors of deformation characteristics definition and then to average quadratic errors of coordinates for laser scanning points. The enlarged stages of scanning are defined with view of tunneling technology of New Austrian method.

Life cycle assessment of tunnel structures: Assessment of the New Austrian Tunnelling Method using a case study

One important measure to combat progressing climate change is compliance with and under no circumstances to exceed the decreasing greenhouse gas budget. Every economic sector must strive to make its ecological contribution to achieve this objective. The construction sector is largely responsible for these negative environmental burdens. Although tunnels are considered to have extensive energy and material consumptions the literature has failed to present their environmental impacts. Aimed at this knowledge gap, the objective of this study is to present the life cycle assessment (LCA) of a tunnel construction project situated in Bulgaria. The study analyzes the impacts of the New Austrian Tunnelling Method (NATM) using the case study “Modernization of Railway Section Elin Pelin-Kostenets – Lot 3”. Moreover, by applying dominance and sensitivity analyses, the environmental drivers and optimization potential for reducing greenhouse gas emissions are identified. The results show that steel, shotcrete, and concrete, contribute the most to the global warming potential indicator and are responsible for 85% of this. Furthermore, the life cycle stages for the production of materials and components have a share close to 85 % of the total global warming potential. These findings may help future tunnelling construction projects to improve the environmental performance and thus to combat the alarming development of climate change.

Compensation excavation method control for large deformation disaster of mountain soft rock tunnel

In recent years, the mine tunneling method and the new Austrian tunneling method have been considered the main theories of tunneling approaches in China. It is difficult for the traditional technique to overcome the large deformation problems imposed by complex geological conditions of mountain soft rock tunneling. Hence, the compensation excavation method has been proposed to solve this issue under the consideration that all damage in tunneling originates from the excavation. It uses supportive strategies to counteract the excavation effects successfully. This paper provides an overview of the fundamental ideas of the compensation excavation method, methodologies, and field applications. The scientific validity and feasibility of the compensation excavation method were investigated through the practical engineering study of the Muzhailing and Changning tunnels.

Excavation compensation method and key technology for surrounding rock control

The change in the stress state of the underground rock caused by excavation is the root cause of the deformation instability. Compensating for the stress change is one of the keys to effectively control the instantaneous deformation of rockbursts and the slow deformation of soft rocks in deep underground engineering. At present, the Platts pressure arch theory and the New Austrian Tunneling Method are commonly used in ground control, but their applicability to high-stress deep rock masses is limited. The strength and elongation of the traditional support materials are insufficient, the prestress is low, and it is difficult to effectively control the large deformation of deep rock masses. In this work, the excavation effect and support compensation effect of the rock are analyzed from the mechanics perspective, and an excavation compensation method suitable for controlling large deformation of deep rocks is proposed. The excavation effect verification experiments are carried out to examine the large deformation failure characteristics. Based on the excavation compensation method, a high prestress excavation compensation control technology is developed by using a new Negative Poisson's ratio (NPR) material. This technology is successfully applied to deep buried hard rocks and soft rocks to realize the effective control of the large deformation, which proves the applicability of the excavation compensation method and technology.

Effects of forepoling, nailing and micropiling on the behaviour of a two-storey tunnel

This study investigates the effects of three improvement methods, the umbrella arch method (UAM), soil nailing and micropiling, on the performance of a new Austrian tunnelling method tunnel in Tehran, Iran. This tunnel passes under Modares freeway, a major artery in Tehran and is part of the Arash project. The construction of a tunnel with a large, approximately square cross-section on a disturbed soil stratum and the existence of adjacent embedded canals (qanat) have made the Modares tunnel one of the most challenging parts of this project. This uncommon square shape was chosen due to limitations caused by adjacent facilities. All combinations of three supporting systems (forepoling UAM, soil nailing and micropiling) were investigated using the numerical method. The influence of these methods on surface settlement and the adequacy of the initial tunnel lining are discussed. In short, forepoling was the most effective with a 24% decrease in settlement compared to the initial model. Combining the forepoling and nailing systems decreased the settlement by 37.5% and was the most effective synchronic system. The best results were for the model incorporating all supporting systems, which was a decrease in the settlement by 47.5%.

Data-driven analytical mechanics of aging viscoelastic shotcrete tunnel shells

Based on the principle of virtual power, equilibrium conditions are established for the forces within a cross section of a tunnel top heading driven according the New Austrian Tunneling Method (NATM). External forces, namely impost actions and ground pressure distributions following a third-order polynomial, are analytically linked with internal forces, such as axial forces and bending moments, arising as integrals over the shell thickness, of circumferential normal stresses. The latter are related, via an aging viscoelastic shotcrete material model, to circumferential normal strains, as well as to radial and circumferential displacement components. This allows for analytical transformation of displacement measurement data collected at the crown and the footings of the shell segment, into ground pressure and impost action evolutions, together with all the associated force and stress quantities. For the Sieberg tunnel, driven in Miocene clay marl, our data-driven analytical mechanics model evidences virtually uniform ground pressure distributions, leading to a first rapidly increasing, and then mildly decreasing utilization degree of the shotcrete shell.

Three-Dimensional Probabilistic Analysis of the Surface Settlement Based on Spatial Variability of Soil Properties: Case Study Zarbalizadeh NATM Tunnel

The design and construction of a tunnel in urban areas need special considerations. Usually, the excessive settlement caused by tunnelling during the construction process damages the adjacent infrastructures and utilities, especially if the tunnel is excavated by the new Austrian tunnelling method (NATM). Thus, it is important to make accurate predictions and effective control on tunnelling-induced settlement. In this study, the soil’s Young’s modulus was modelled using a three-dimensional random field and coupled with a finite difference method (FDM) analysis to reveal the scale of fluctuations (SOF) effects on the maximum surface settlement (Smax). The Fourier series method is employed to generate the field of Young’s modulus for soil, and sensitivity studies are further performed via Monte-Carlo simulations (MCS). The results demonstrate that the mean value of Smax increased from 28 to 31 mm and its coefficient of variation (COV) increased from 0.02 to 0.35, with an increasing horizontal SOF but both stabilize at higher values of SOF. Furthermore, the probability of failure increases as the COV increases for each allowable limit greater than the verification FDM of Smax. It is observed that ignoring the spatial variability of the soil properties leads to an underestimate of excessive surface settlement risk.

Evaluation of a Preliminary Support Design of Railway Tunnel Adit in Inner Lesser Himalaya India: An Empirical Analysis

This article addresses the excavation method and support design for the adit tunnel in the Rudraprayag District, Lesser Himalayas of India, using Rock Mass Rating (RMR), Tunneling Quality Index (Q), and New Austrian Tunneling Method (NATM). Based on ONORM B 2203 correlations with RMR and Q systems, the New Austrian Tunneling Method rock structure classes were developed. Because the geology was constantly changing, NATM concepts were applied. The RMR-based rock mass estimates were overestimated, but the qualitative investigation was correct. The NATM method is more appropriate for a Garhwal Himalayan rock with varying rock mass uncertainty. The present adit research reveals several outstanding questions about rock mass quality, tunnel behavior during construction, and use. The analysis results might be used to build new tunnels in comparable terrain in other parts of the world.

Prerequisites for BIM‐based invoicing in NATM projects

AbstractThe successful management of big tunnelling projects requires the complete documentation of technical and financial data as well as their ongoing evaluation. The current study reviews the possibilities for digital documentation of tunnel construction with the subsequent integration of this data with an invoicing software. It suggests an implementation model, a building information modeling (BIM) project element list and a digital on‐site data recording tool for a workflow in New Austrian Tunnelling Method (NATM) projects. This digital resource enables central data management that improves and speeds up automated invoicing processes.

The Tunneling Information Management System – A tool for documenting the tunneling process in NATM projects

AbstractThe 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.

The application of reinforcement learning to NATM tunnel design

The New Austrian Tunnelling Method (NATM) tunnel design is performed by testing support classes against the geological profile. We propose to replace this manual process with reinforcement learning, a generic framework within the realm of artificial intelligence that solves control tasks. Previous studies have demonstrated this possibility, albeit with methodological simplifications. We coupled the Finite Difference Method with a Python script, used the output of the first to train the machine learning model implemented in the latter and improved the choice of the support classes. Through benchmark tests, we demonstrated that our method was capable of choosing the optimal support classes for various geological sets and showed the relation between its performance and the number of training episodes.

Investigation of the support constraint effect and failure instability law of tunnels constructed using the New Austrian tunneling method

The application of a reasonable numerical calculation method is the key to accurately analyzing tunnel rock-support interactions. In this paper, we address the support constraint effect of tunnels and analyze the influence of related factors based on the confinement convergence method. Rupturable support models are developed using FLAC3D to intuitively show the numerical calculation results of tunnels. The results imply that the virtual supporting force generated by the support constraint effect should be considered in two-dimensional rock tunnel model calculations, and that the supporting force of the support should be increased by 2–3% of the maximum supporting force. Boundary effects should be considered in the three-dimensional tunnel model calculations, in which the influence range of the model boundary effect is nearly 1.5 times the tunnel span. A comparison of the field monitoring data and numerical calculations of the Baoshan tunnel project shows that the numerical results that consider the support constraint effect are in better agreement with the actual project situation. The rupturable support models can also reflect the stress and failure evolution law of supports, and provide support for the accurate evaluation of tunnel engineering stability.

Analysis of Stability and Required Offset with Vibration Velocity Considering Conditions of Bedrock and Explosive Charges Using the TBM and NATM Extension Blasting Method

The development of underground spaces in urban centers has attracted significant research attention. Typical excavation methods for underground spaces in urban areas include the New Austrian tunneling method (NATM) and the tunnel boring machine (TBM). The NATM is superior in terms of ease of construction and economic efficiency; however, vibration and noise are often cited as major complaints. In addition to their high initial cost, TBMs require intricate analyses of ground conditions during excavation. To overcome the disadvantages of both methods and reduce construction time, a TBM and NATM parallel excavation method has recently been investigated. In this study, the effects of blasting vibrations on the TBM, TBM backup device, and surrounding ground were examined during an NATM application for rear expansion blasting after pilot tunnel excavation using a TBM. Different rock types and powder factors were simulated, and differences in the vibration velocity according to their variations were predicted using 3D numerical analysis.

The comparative analysis of the stress-strain state of the support of the escalator tunnel constructed in weak soils by the NATM

The construction of underground objects of the subway is always associated with building of structures connecting the surface. For subways, such structures are escalator tunnels. During the construction of the Dnipro Metro, these underground structures are built using a new technology that forms a multilayered support. This technology is the New Austrian tunneling method. A special feature of its application under the conditions of the Dnipro city is the existence of weak rocks in the upper part of the escalator tunnel. To ensure their stability, various special operational techniques are used that impact the rock massif. The basic techniques include artificial freezing, which was the dominant strengthening technology, and chemical strengthening (cementation), which is more consistent with the New Austrian tunneling method. To elucidate the effectiveness of the two strengthening techniques, a finite-element model of the Dnipro Metro escalator tunnel has been built. The numerical calculation of two variants for the strengthening of weak soils yielded results for a comparative analysis of the stress-strain state. The result of the comparative analysis is the conclusion of greater cementation efficiency when strengthening weak soils of the massif in which the escalator tunnel is constructed using New Austrian tunneling method.

Kil Zeminlerde İnşa Edilen Tünellerdeki Deformasyonlara Aşırı Konsolidasyon Oranının Etkisi

With the globalization of the world, it has become necessary to create new routes for transportation due to the decrease in usage areas for construction and accelerated living conditions. For these reasons, some of the road and railway routes selected for transportation are passed through tunnels. In addition, with the increase in population in metropolitan cities, necessitated transportation by rail systems so tunnel constructions became a necessity here. However, these tunnels made on clay soils can cause major problems. Due to these problems, routes change, construction projects cannot be completed, and even during tunnel construction, tunneling devices become stuck in the tunnel and become unusable. In this study, the deformations of tunnels made in clay soils with different over consolidation ratios were investigated by using Plaxis2D program, which analyzes with the finite element method. The tunnel model was created using the New Austrian Tunneling Method (NATM) and the deformations in the clay soil were determined under static and dynamic loading conditions.

Investigation of Twin Tunnel Deformation with Umbrella Grouting Protection & NATM Tunneling using 3D Finite Element: Case Study Cisumdawu Tunnel

Cisumdawu Tunnel is a twin tunnel 472 m long located in Sumedang. Twin tunnel construction can cause additional ground settlement and tunnel deformation. The tunnel construction method used is the New Austrian Tunneling Method (NATM) and umbrella grouting protection system. The principle of NATM is to maximize surrounding soil capacity to support its weight and balance the stresses around the tunnel. Investigation of tunnel deformation is important to know tunnel structure behavior and avoid possible failure. This research aims to know tunnel deformation and the effect of twin tunnel construction on the deformation and ground settlement. The data used such as tunnel geometry, monitoring data, pressuremeter test, and the drilling test. The 3D analysis will be performed for a single tunnel and twin tunnel using Midas GTS-NX, and monitoring data will be used for verification analysis. The 3D FEM help to model the soil condition and construction stage according to the actual condition. The analysis results show the maximum tunnel deformation that occurs from the beginning of the tunnel construction is 12.64cm. If the deformation starts to be calculated following the monitoring reading time, after the excavation at the monitoring point, the maximum deformation of the analysis results is 3.3&4.4cm, where the monitoring shows maximum deformation of 3.3&4.3cm. Through the results, it can be said that the analysis using 3D FEM with pressuremeter test parameter represents actual conditions. Twin tunnel construction side-by-side increases ground settlement and lateral tunnel deformation significantly. Hence, it shows that tunnel analysis using 3D FEM recommends for future investigation of tunnel deformation.

New Railway Tunnels and their Construction Method as Well as their Impact to Train Operation

Abstract 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.

Effects of different processes of tunneling on displacements soil using 3D Finite Element Method

Abstract The excavation process of tunnels induces stresses and deformation in the surrounding soil. The method of excavation is one of the major problems related to the safety of the operators and the ground stability during the construction of underground works. So, it is necessary to choose an ideal method to minimize the displacements and stresses induced by tunneling. The main aim of this study is to simulate numerically the effect of different processes of tunneling on ground displacements, the settlements at surface soil and the internal efforts induced in the lining tunnel; in order to select the best process of excavation, which gives us a less effects on displacements generated by tunneling, thus, ensuring the stability and the solidity of the underground constructions. In addition, this study allows us to control and to predict the diverse movements generated by tunneling (displacements, settlements, efforts internes) exclusively for the shallow tunnel nearby to the underground constructions in the urban site. This modeling will be done by employing five different processes for tunnel excavation using the NATM (New Austrian Tunneling Method) method. The first process, the modeling of the excavation tunnel, is done almost in the same way as in reality; the partial face excavation, with seven slices, made by the excavation. The second process, by partial face excavation, is divided into eleven slices, next, we used the partial face excavation by nine slices, and then in thirteen slices. Finally, the dig is made by full-face excavation. The paper contributes to the prediction of the response of the soil environment to tunnel excavation using the NATM method and to minimize the diverse movements generated by tunneling. The appropriately chosen methodology confirms that displacements and subsidence are strongly influenced by the tunneling method. The three-dimensional Finite Elements Method using Plaxis3D program has been applied in the numerical simulation. The study resulted in the recommendation of a process that minimizes the effect of excavation on subsidence and ground displacement for a particular Setiha tunnel.

Engineering Geological Investigation of the Kırık Tunnel Route

Engineering structures are of great importance in the comfort and safe travel of people who prefer the highway in the existing transportation networks. Highway tunnels are one of the most important engineering structures that easily overcome transportation problems. This study investigates the geological and geotechnical structures of the Kırık tunnel on the Erzurum-Rize highway route, makes the rock mass classification required for tunnel excavation according to the New Austrian Tunneling Method and determines the tunnel support systems. Geological mapping, drillings, geological- geotechnical investigation based on in-situ and laboratory tests were carried out in order to reveal the physical and mechanical properties of the geological formations on the tunnel and to determine the basic data required by the project. It is divided into 4 classes on the basis of NATM Rock Classification along the tunnel axis. Rock support types related to rock classes defined as B1, B2, B3 and C2.