design of rock bolts for tunnels usage

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  • IMPROVING ROCK BOLT DESIGN IN TUNNELS USING

    2015-11-23 · 1 IMPROVING ROCK BOLT DESIGN IN TUNNELS USING 2 TOPOLOGY OPTIMISATION Tin Nguyen1, Kazem Ghabraie2, Thanh Tran-Cong3, Behzad Fatahi4 3 4 ABSTRACT 5 Finding an optimum reinforcement layout for underground excavation can result in a 6 safer and more economical design, and therefore is highly desirable. Some works in the

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  • DESIGN OF ROCKBOLT AND SHOTCRETE FOR TUNNELS

    2009-12-31 · In this paper, the use of rockbolts and shotcrete for tunnels excavated through jointed rock is modelled using the distinct element method. The geometry and mechanical properties of joints have a considerable effect on the stresses and deformations developed in the rockbolts and shotcrete. The effect of various parameters pertaining to joints including joint spacing and orientation, friction angle, cohesion and dilation angle of the joints on the design of fully grouted rockbolts …

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  • Recent Trends on Rock Bolting in Tunnel Construction

    2014-10-11 · F. Self-drilling bolts The principal objective in the design of a roof support system is to help the rock mass create a self-supporting structure. The usage of rock bolts can be combined with wire mesh, shotcrete and concrete lining to cope with different situations encountered during …

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  • An empirical method for design of grouted bolts in

    2009-8-14 · The RMR system of Bieniawski, 1973, Bieniawski, 1989 has been acknowledged to be applicable to fully grouted rock bolts in all type of rock masses. The design tables and recommendations proposed by Bieniawski are intended for tunnels in the order of 10 m width, excavated by the drill and blast method at depths of less than 1000 m and reinforced by 20 mm diameter grouted bolts.

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  • (PDF) Recent Trends on Rock Bolting in Tunnel

    The procedure presented in this paper has been developed for the design of grouted rock bolts in rock tunnels during preliminary design stage. The proposed approach provides a step-by-step...

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  • An empirical method for design of grouted bolts in

    2019-8-14 · The procedure presented in this paper has been developed for the design of grouted rock bolts in rock tunnels during preliminary design stage. The proposed approach provides a step-by-step procedure to set up a series of practical guidelines for optimum pattern of rock bolting …

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  • An empirical method for design of grouted bolts in

    2020-10-13 · CHAPTER 5. ROCK BOLTING DESIGN FOR UNSTABLE ROCK WEDGES 5.1 Introductio 10n 4 5.2 Assumption 10s 5 5.3 Locatin 10g a wedge 6 5.3.1 Coordinat 10e system 7 5.3.2 Some definition 10s 9 5.3.3 Coordinate point on any plane Ils of a l 5.3.4 Equation strike line of a discontinuitsy o planf e on the projection level 112

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  • 1994 Design of rock bolting systems for underground ...

    1.4.2. Rock bolts Rock bolts are used as primary support materials just like shotcrete. The main anchorage method for rock bolts is a full-faced anchorage. For cases in which a rock bolt hole cannot stand alone, a self-boring type of rock bolt may be employed. When rock bolts are anchored to the ground, the friction is increasing. The

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  • Design and construction ofmountain tunnels in Japan

    2 天前 · Since about 1960, rock bolts have had major success in providing the sole support for large tunnels and rock chambers with spans up to 100 feet. Bolts are commonly sized from 0.75 to 1.5 inches and function to create a compression across rock fissures , both to prevent the joints opening and to create resistance to sliding along the joints.

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  • IMPROVING ROCK BOLT DESIGN IN TUNNELS USING

    2015-11-23 · 1 IMPROVING ROCK BOLT DESIGN IN TUNNELS USING 2 TOPOLOGY OPTIMISATION Tin Nguyen1, Kazem Ghabraie2, Thanh Tran-Cong3, Behzad Fatahi4 3 4 ABSTRACT 5 Finding an optimum reinforcement layout for underground excavation can result in a 6 safer and more economical design, and therefore is highly desirable. Some works in the 7 literature have applied topology …

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  • DESIGN OF ROCKBOLT AND SHOTCRETE FOR TUNNELS

    2009-12-31 · DESIGN OF ROCKBOLT AND SHOTCRETE FOR TUNNELS IN JOINTED ROCK Massoud Palassi, Department of Civil Engineering, University of Tehran, Iran ... l'usage de rockbolts et shotcrete pour les tunnels creusé par le rocher de jointed est modelé l'utilisation ... the bolts are generally left ungrouted. For more permanent applications, the space ...

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  • Practical Method for the Design of Pretensioned Fully ...

    Practical Method for the Design of Pretensioned Fully Grouted Rockbolts in Tunnels ... the pretensioned fully grouted bolt is calculated by the assumption of a rigid connection between the bolt and the rock mass. A compressive force is then applied to the bolt head on the tunnel surface to consider the shear relative displacement between the ...

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  • An empirical method for design of grouted bolts in

    The procedure presented in this paper has been developed for the design of grouted rock bolts in rock tunnels during preliminary design stage. The proposed approach provides a step-by-step procedure to set up a series of practical guidelines for optimum pattern of rock bolting in a variety of rock mass qualities. For this purpose, a new formula for the estimation of the rock load (support ...

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  • Practical Rock Engineering Chapter 14 Rockbolts and Cables

    2018-9-21 · installation. For short term applications the bolts are generally left ungrouted. For more permanent applications or in rock in which corrosive groundwater is present, the space between the bolt and the rock can be filled with cement or resin grout. Dowels or anchor bars generally consist of deformed steel bars which are grouted into the rock.

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  • ANALYTICAL DESIGN OF ROCK-BOLT SYSTEMS

    2010-3-23 · grouted bolts as well as swellex bolts will mainly be analyzed in the thesis. In the following, four constitutive models developed for the design of rock-bolt system based on analytical methods will be discussed. In is of great importance to utterly acquaint with those models involving the rock-bolts, rock mass interaction. 3.

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  • IS 15026 (2002): Tunneling Methods in Rock Masses ...

    2018-4-7 · The design of underground excavations is, to a large extent, the design of underground support system. These can range from no support in the case of a temporary excavation in good rock to the use of fully grouted and tensioned bolts or cables with mesh; and sprayed concrete of Steel Fibre Reinforced Shotcrete (SFRS) or steel

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  • Rock Anchoring and Bolt Systems

    2020-2-29 · anchors and tensioning procedures for rock bolts are detailed in this publication. Failure to follow approved practices, may result in failure. 3. The applied safety factor for a product will depend on the degree of hazard or risk involved in the product application. This safety factor is governed by national codes, local codes

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  • Determining Rock Bolt or Anchor Tension Using a Torque

    2016-7-19 · Rock bolts are used for support in a variety of engineering applications. This test provides a quantitative measure of the performance of a rock bolt or its anchor. 4.2 Tension.-At least 5 percent of the installed rock bolts or their anchors should be tested to verify if the rock bolts or their anchors have the specified tension. 5.

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  • Guideline for Design of Road Tunnel

    2018-3-27 · tunnels is a cavity which is located below the ground surface and is used in some way and made into a prescribed geometry and has a size of two square meters or more. 1.2 Construction Method of T unnels In Japan, there are three kinds of general-purpose specifications for building tunnels. These are rock tunnel, shield tunnel, cut and cover tunnel.

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  • An Empirical Method for Design of Grouted Bolts In

    An Empirical Method for Design of Grouted Bolts In Rock Tunnels Based on the Geological Strength Index (GSI) Reza Osgoui. Related Papers. GSI TUNNEL BOLT. By Yuri García. Engineering geological and geotechnical investigations along the head race tunnel in Teesta Stage-III hydroelectric project, India.

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  • DESIGN OF TUNNELS IN VARIOUS ROCK CONDITIONS

    2015-4-2 · 15 Design of tunnels in various rock conditions Austrian Tunnelling stSeminar Ankara, March 31st & April 1 , 2015 Uncertainties Determination of „real“ rock mass parameters is usually very difficult. Methods like Hoek-Brown rely on simplifications and estimations.

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  • Rock Support Interaction analysis for tunnels in weak rock ...

    2018-9-21 · This Rock-Support Interaction or Convergence-Confinement analysis is limited to circular tunnels in an in-situ stress field in which all three principal stresses are equal and where the rock mass exhibits elastic-perfectly plastic shear failure. It should not be used for the detailed design of tunnels in more complex rock masses and in-situ

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  • Rock Anchoring and Bolt Systems

    2020-2-29 · anchors and tensioning procedures for rock bolts are detailed in this publication. Failure to follow approved practices, may result in failure. 3. The applied safety factor for a product will depend on the degree of hazard or risk involved in the product application. This safety factor is governed by national codes, local codes

    Get Price
  • The effect of pretensioning in the rockbolts on the ...

    2021-3-25 · the strength between rock layers increases and the rock mass becomes stabil. For stressed rock masses, increasing the minimum stress or confinement degree can stabilize the rock mass. In tunnels generaly the minimum main stress is perpendicular to the tunnel wall. So if the under tension rock bolts …

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  • DESIGN OF SPRAYED CONCRETE FOR UNDERGROUND

    2013-5-30 · and rock bolts was introduced in 1956 by the Austrian engineer L. von Rabcewicz during the construction of highway tunnels near Caracas). These approaches, which aim at making the best use of the ability of the ground to “support itself”, assume that the primary role of the support system is to pro-vide ground confinement immediately after

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  • LIMITATIONS OF ROCK MASS CLASSIFICATION SYSTEMS

    2011-7-4 · portion of the international rock mechanics fraternity, particularly those involved in support design for rock tunnels. Here appeared to be systematic, if not truly scientific, procedures for designing primary support. Over the past 30 years the two classificationsystems have been proposed as being design tools for a wide range of structures.

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  • The Design and Construction of Tunnels and Shafts in

    2018-3-4 · Often times tunnels and shafts have to be placed in rock, which can then create the need for additional design, planning and construction criteria than tunnels through soil. After reading this course the student will know the basic information regarding tunnels and shafts in rock.

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  • Determining Rock Bolt or Anchor Tension Using a Torque

    2016-7-19 · Rock bolts are used for support in a variety of engineering applications. This test provides a quantitative measure of the performance of a rock bolt or its anchor. 4.2 Tension.-At least 5 percent of the installed rock bolts or their anchors should be tested to verify if the rock bolts or their anchors have the specified tension. 5.

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  • Reliability-Based Robust Geotechnical Design of Rock

    2015-3-17 · Abstract. In this paper, a robust geotechnical design (RGD) methodology is applied to design of rock bolts for slope stabilization. In rock engineering practice, the variation of shear strength characteristics of rock discontinuities is often quite difficult to ascertain. The RGD methodology is utilized to achieve a certain level of design ...

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  • Rock reinforcement design for unstable tunnels originally ...

    2010-4-6 · Today, rock bolting is used in almost all types of underground constructions. Knowledge of the rock mass behavior and support effects of rock bolts are vital for the design and construction of underground structures in rock. Malatya- Narli No: 7 railroad tunnel, situated at the central part of turkey, is a rail-road one that was

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  • Draft Specification of Various Items of Tunnels

    2018-2-27 · etc.) of rock bolts to be used may vary according to design and site requirements. The diameter of rock bolts depend on the mass of the rock to be supported by each rock bolt and the force of resisting shear in the bedrock. EN 1997-1 – Geotechnical Design …

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  • The Design and Construction of Tunnels and Shafts in

    2018-3-4 · Often times tunnels and shafts have to be placed in rock, which can then create the need for additional design, planning and construction criteria than tunnels through soil. After reading this course the student will know the basic information regarding tunnels and shafts in rock.

    Get Price
  • Critical Assessment of RMR based Tunnel Design

    2021-6-14 · Original guidelines for support of rock tunnels based on the RMR system (Bieniawski 1989) DESIGN OF SUPPORT SYSTEMS FOR UNDERGROUND EXCAVATIONS Design Load Rock load on a support system is a function of rock mass condition and initial stress state. Where the rock mass ... The capacities of the rock bolts and the shotcrete

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  • Rock Support Interaction analysis for tunnels in weak

    2018-9-21 · This Rock-Support Interaction or Convergence-Confinement analysis is limited to circular tunnels in an in-situ stress field in which all three principal stresses are equal and where the rock mass exhibits elastic-perfectly plastic shear failure. It should not be used for the detailed design of tunnels in more complex rock masses and in-situ

    Get Price
  • DESIGN CONSIDERATIONS FOR UNDERGROUND

    design considerations for underground structures in rock. ... two types of linings were developed for the permanent support of rock tunnels: (1) for areas with rock quality (rq) 60 percent and over, rock bolts and shotcrete are used, and (2) for areas with rq below 60 percent, rock bolts and shotcrete or steel sets combined with cast-in-place ...

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  • CHAPTER 9 PRELIMINARY DESIGN OF TUNNEL

    2015-4-14 · Convergence of tunnels is negligible. CⅠ Rock is partly weathered or altered. Discontinuous planes are generally relatively stable 20 to 70 The strength is higher than the expected load and the loosening is expected to be local. Convergence of tunnels is usually within the elastic range. CⅡ Rock is partly weathered or

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  • TUNNELS, SHAFT AND DEVELOPMENT HEADINGS BLAST

    2018-4-25 · _____Tunnels, Shaft, and Development Headings Blast Design REVEY Associates, Inc. 2005 Page 3 ROCK CHARACTERISTICS Rock conditions have great influence on blast design and results. Designers can not choose rock conditions, but they can study and define the characteristics of existing rock.

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  • LIMITATIONS OF ROCK MASS CLASSIFICATION SYSTEMS

    2011-7-4 · portion of the international rock mechanics fraternity, particularly those involved in support design for rock tunnels. Here appeared to be systematic, if not truly scientific, procedures for designing primary support. Over the past 30 years the two classificationsystems have been proposed as being design tools for a wide range of structures.

    Get Price
  • Design of rock bolting systems for underground

    Stability of underground structures is critical in underground mining. Every effort must be made to preserve stability for the safety of mining operations. There are a number of techniques available for reinforcing unstable rock masses, of which rock bolting is the most widely used. Due to the complexity of geological conditions and the variety of mining methods employed, reinforcement methods ...

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  • Critical Assessment of RMR based Tunnel Design

    2021-6-14 · Original guidelines for support of rock tunnels based on the RMR system (Bieniawski 1989) DESIGN OF SUPPORT SYSTEMS FOR UNDERGROUND EXCAVATIONS Design Load Rock load on a support system is a function of rock mass condition and initial stress state. Where the rock mass ... The capacities of the rock bolts and the shotcrete

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  • Analytical model for the design of grouted rock bolts ...

    A dimensionless parameter is introduced as a design tool which relates the tunnel convergence to the bolt spacing for a given bolt length. This publication contains the derivation of the analytical model and an illustration of the effect of bolts on the stress and displacement field near an opening.

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  • CHAPTER 11 DESIGN AND SUPPORT OF TUNNELS:

    6. Various bolt mediums are available including wood dowels, wire cables and steel. 3. Shotcrete 1. Commonly used in conjunction 1 . Application of shotcrete is with rock bolts and mesh as a dependent upon skill of the nozzle temporary support system in operator. rock tunnels where a concrete 2.

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  • DESIGN CONSIDERATIONS FOR UNDERGROUND

    design considerations for underground structures in rock. ... two types of linings were developed for the permanent support of rock tunnels: (1) for areas with rock quality (rq) 60 percent and over, rock bolts and shotcrete are used, and (2) for areas with rq below 60 percent, rock bolts and shotcrete or steel sets combined with cast-in-place ...

    Get Price
  • Design and Construction of Road Tunnels: Part 1 Planning

    2017-5-17 · Road tunnels are often lined with concrete and internal finish surfaces. Some rock tunnels are unlined except at the portals and in certain areas where the rock is less competent. In this case, rock reinforcement is often needed. Rock reinforcement for initial support includes the use of rock bolts …

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  • Analytical Solution for Bolted Tunnels in Expansive

    Ground reinforcement using bolts is effective for underground excavations. The ground response of expansive loess tunnels with bolt reinforcement remains poorly understood. Therefore, this paper proposes an analytical solution for bolted rock in expansive ground using the convergence-confinement method.

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  • Tunnel Support Design - Tunneling Short Course

    2018-10-2 · Tunnel Support Design Summary Summary • Project-specific ground characterization • Compatible excavation methodology –Hard rock tunnel: rock mass discontinuities, strength and abrasion –Soft-ground tunnel: continuous face and periphery support GW control monitoring • Contingency –Risk Mitigation measures: pre-support ground treatment temporary invert support

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  • HISTORY OF ROCK BOLTING – Mining Science and

    Rock bolting is one of the most efficient supporting devices ever developed. The earliest case of using bolts as a rock reinforcement method was in a slate quarry in North Wales in 1872 (Schach et al., 1979).In 1918 a coal mine in Germany introduced bolts as a means of ground reinforcement (Lang et al.1979).Mechanical rockbolts were applied in a metal mine in the United States in 1927 (Bolstad ...

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  • Design of Tunnel Support Systems

    Rock Tunnels Three main types of primary support systems are presently used in rock tunnels in the United States. They are rock bolts, steel sets, and shotcrete. Shotcrete is a pneumatically applied large-aggregate concrete. The need for a secondary lining in a tunnel supported by shotcrete depends on the purpose of the tunnel. Table 1 gives pres­

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  • TBM & Rock Bolts in Tunnel - Rockbolt|Sinorock

    2017-1-9 · TBM & Rock Bolts in Tunnel. The 6.7km long, 9.9m diameter twin Bolaños rail tunnels have been completely bored on the Madrid-Galicia High-Speed Line for client in Spain. A Herrenknecht S-511 single shield TBM has been used to construct the two tunnels through ground conditions consisting of shales, quartzite, phyllite and sandstones.

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  • Design and Construction of Road Tunnels: Part 1 Planning

    2017-5-17 · Road tunnels are often lined with concrete and internal finish surfaces. Some rock tunnels are unlined except at the portals and in certain areas where the rock is less competent. In this case, rock reinforcement is often needed. Rock reinforcement for initial support includes the use of rock bolts …

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  • TUNNEL DESIGN BY ROCK MASS CLASSIFICATIONS

    2011-5-15 · 1. The design of tunnels in rock currently utilizes three main approaches: analytical, observational, and empirical. In view of the very complex nature of rock masses and the difficulties encountered with their characterization, the analytical approach is the least used in the present engineering practice. The reason for it does not lie in the ...

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  • CHAPTER 11 DESIGN AND SUPPORT OF TUNNELS:

    6. Various bolt mediums are available including wood dowels, wire cables and steel. 3. Shotcrete 1. Commonly used in conjunction 1 . Application of shotcrete is with rock bolts and mesh as a dependent upon skill of the nozzle temporary support system in operator. rock tunnels where a concrete 2.

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  • Tunnel Support Design - Tunneling Short Course

    2018-10-2 · Tunnel Support Design Summary Summary • Project-specific ground characterization • Compatible excavation methodology –Hard rock tunnel: rock mass discontinuities, strength and abrasion –Soft-ground tunnel: continuous face and periphery support GW control monitoring • Contingency –Risk Mitigation measures: pre-support ground treatment temporary invert support

    Get Price
  • Analytical Solution for Bolted Tunnels in Expansive

    Ground reinforcement using bolts is effective for underground excavations. The ground response of expansive loess tunnels with bolt reinforcement remains poorly understood. Therefore, this paper proposes an analytical solution for bolted rock in expansive ground using the convergence-confinement method.

    Get Price
  • Design and Construction of Road Tunnels: Part 2 ...

    2017-5-17 · systems for cut-and-cover road tunnels, design and construction issues for rock and soft ground tunneling, and the special approaches that must be made when passing through difficult ground. Grading: Students must achieve a minimum score of 70% on the online quiz to pass this course. The quiz may be taken as many times as

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  • Recent Advances in Rock Engineering (RARE 2016)

    (1) where E[g(d, θ)] is the mean and σ[g(d, θ)] is the standard deviation of the output at a given design set d.Higher is the value of SNR, more robust the design would be. III. PDESCRIPTION OF THE ROCK SLOPE T A sample rock slope of height 82m 'Fig. 1' is to be reinforced by end anchored rock bolts.

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  • Sensing and monitoring in tunnels testing and

    2020-3-3 · The design standards or guidelines implemented for each project are therefore selected and applied by the tunnel owner or by the related authority. However, the project-specific rock or soil conditions, the several possible types of tunnel by use, and the excavation and support methods not necessarily do, thus increasing the variation in the ...

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