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1. The following recommendations should apply to all mines, tunnels and underground quarries, but to opencast quarries only in so far as persons can be exposed to dust injurious to health. General In the present state of knowledge, all duets liberated in mining, tunneling and quarrying operations should be considered potentially injurious to health if breathed in sufficient quantity; dusts containing free silica should be considered specially injurious to health, the injurious particles being below 7 microns in diameter.

Jan 1, 1954

By Sammie D. Guy

This paper discusses the subject of "Improving Contracting Methods" from the owners point of view, particularly the public. An overview is given of the work of the U.S. National Committee on Tunneling Technology and some apparent results of the implementation of these recommendations or lack thereof. Selected recommendations that are not being implemented are discussed as to the the desirability and the possible impact of their implementation. Impediments to acceptance of the recommendations are identified and solutions proposed. The difference in the flexibility, attitudes and approaches of owners, public, quasi-public and private, toward improving contracting methods are discussed. Particular emphasis is given to the fact that the onus to improve is on the owner because they usually develop the contractual language or at least have the final decision on its content and are or should be an equal party to the contract during its administration.

Jan 1, 1983

By Drupad B. Desai, James G. Gallanes

A key component of the Inland Feeder Project is the Riverside Badlands Tunnel, a7.9-mile stretch subjected to high internal and external hydraulic pressures passing beneath highly eroded hills in a semi rural environment. The tunnel presented significant design and management challenges to the project team. This paper describes the formula for project success used to manage the design of this complex pressure tunnel, from team member selection to the completion of all contract documents, on schedule and below budget. The project team dealt with sensitive regional and local community issues and won the trust of the community. The team included participation by senior management and recognized experts from inception to finish. The team worked diligently to build quality into design and adopted a claims avoidance approach to management and preparation of documents.

Jan 1, 1997

By Shelley M. Burg, Dennis K. Poulton, Robert B. Gordon

This project includes the excavation and concrete lining of approximately 18 900 m (62 000 ft) of 5.5 m (18 ft) finished diameter subway tunnel for the Los Angeles MTA. The project required that four soft ground headings be excavated from a single shaft located near the mid point of the tunnels. The tunnels were classified "gassy" during the excavation phase. Because of the contract schedule requirements and the limited urban work site available, many logistical problems had to be overcome during the project while excavation was accomplished at a record setting pace. Some unique project features include the muck handling system and an access shaft using a high strength tieback support system. In order to accomplish the work, an extensive effort to plan and construct the main work site was required.

Jan 1, 1995

This paper discusses the recently com- pleted TBM-driven pressure tunnel at the Sand Bar Hydroelectric Power Project. The Sand Bar Project is a diversion scheme situated on the middle fork of the Stanislaus River in the Western Sierra Nevada, California, U.S.A. As part of the project, a 5.6 km long and 3.71 m diameter unlined pressure tunnel was bored by a Jarva TBM at the average rate of .37.5 m/ day. This report deals with construction aspects of the tunnel, including TBM performance, lining design, and remedial support measures. Correlations between TBM performance, geologic conditions, and rock properities are made, and the Contractor's mode of operations are discussed. Advance rate prediction, and the impact of these excellent advance rates attainable in hard rock using the new machines are discussed.

Jan 1, 1987

By Weining L

In-situ experiments were performed in a tunnel built in loess soil with the displace- ment components of the tunnel lining and the acceleration components of the tracks measured during the passing of trains. The measured parameters were then studied by the spectral method. As a result, the dynamic forces of trains was simulated numerically and a deter- ministic dynamic nonlinear analysis was carried out by means of finite element method. The results obtained by two different approaches were in fair coincidence. Results of the study indicate, that the low and medium frequency components of the dynamic train loading would be crucial for the dynamic responses of the tunnel lining and surrounding mass, and their effects would increase with the speed of passing trains within a certain range.

Jan 1, 1987

This paper describes the programing and specification requirements which affected the choice of excavation methods on the Melbourne Underground Rail Loop (M.U.R.L.). The various methods that were chosen are briefly described, and the three most used are compared in more detail. Excavation rates, cycle times and other statistics are compared for full face tunnel boring, full face drill and blast, and heading and bench using a road header excava- ting machine. The length of tunnel excavated is sufficient to enable meaningful statistics to be presented and the significant specifi- cation and geological factors are described to weight the statistics where necessary for purposes of comparison. Average tender prices are given for excavation and primary support to indicate the reimbursement sought by contractors to carry out this type of tunnelling.

Jan 1, 1981

By William Connell

NFPA 502, Standard for Road Tunnels, Bridges and Other Limited Access Highways establishes minimum fire protection and fire life safety requirements for road tunnels, bridges and other roadways where access by emergency responders is physically limited. The 2008 edition of NFPA 502 represents the Technical Committee?s consensus of current best practice for fire protection and life safety requirements for road tunnels, bridges and similarly limited access highways. Research of national and international test programs, design guidelines and regulating standards was per-formed and considered in an effort to establish a singular, comprehensive document representing a recognized base threshold of fire safety in these type facilities. This paper provides an overview of the more significant revisions including the application of fixed fire suppression systems, guidance on tenable environment, protection of structure and dangerous goods transport.

Jan 1, 2008

By Carl R. Peterson

This report describes the development and testing of a prototype tunneling machine. Principal efforts were aimed at testing of the fragmentation subsystem of a continuous drill and blast hard rock excavation machine suitable for use in underground mining and tunneling applications. The concept utilizes a unique self -shielding spiral blasting pattern that permits efficient performance with relatively small single shots, while at the same time directing major blast fragments at right angles to the tunnel axis. A major accomplishement was the development of a remote controlled, loading and initiation system in which explosive slurry and a detonator are Simultaneously placed (pumped) into the blasthole via a loading hose. The special electric long-delay detonator is inductively ignited upon emplacement, and the machine remains at the face during the blast.

Jan 1, 1976

By Jeroen van Eldert, Daniel Johansson, Henrik Ittner, Håkan Schunnesson

"Numerous aspects of underground construction, from structural stability to construction costs, depended on the tunnel quality, including blast damage and the Excavation Damage Zone. Accurately quantifying the extent and severity of damaged rock is a problem. Recent technical developments in the field of Measurement While Drilling (MWD), including software for on-board logging and on-site analysis, have shown potential for rock-mass characterization. Ground Penetrating Radar (GPR) and P-wave velocity measurement have also improved and show similar potential. This paper explores the use of MWD, GPR and P-wave velocity measurements and uses them in techniques for excavation damage characterization and prediction. The paper is based on data collected from a small underground waste-collection site in central Stockholm, Sweden. The data is correlated against rock-mass characteristics and their responses are evaluated. Results indicate potential for excavation damage characterization for all tested techniques, which could minimize blasting damage and improve the over-all tunnel quality. 1 INTRODUCTION During underground excavation the rock mass is influenced in many ways. The Excavation Damage Zone (EDZ) is a result of these influences. The EDZ can be defined by an irreversible change in rock mass properties, for example increased permeability. EDZ is influenced by the excavation method, the rock mass properties and the in-situ stresses in the area of the tunneling. Since the 1990s research has been done on the EDZ by Emsley et al. (1997), Christiansson et al. (2005), Olsson et al. (2009), Ouchterlony et al. (2009), Ittner et al. (2014), and Siren et al. (2015). Based on past literature the EDZ have in this paper been separated in the following subzones: 1. Failure Zone or over-break is the area outside the planned tunnel profile, including the Look-Out and hole deviation. This zone consists of fracture networks (both natural and blasting-induced), that caused rock fall-outs. The extent of the over-break can be determined by volumetric scanning and photogrammetry and the half cast factor can be used as a damage indicator. 2. The Damaged Zone is split into three parts and but the quantity and depth of damage is difficult to measure. Although it can be visualized by sawing of rock slices in the tunnel wall (Olsson et al. 2009), diamond coring (DC) or P-wave velocity reduction (Jern 2001): a. Inner Damage Zone (Crush Zone): It is located directly around the drill hole, and is caused by the shock-wave energy of the detonation. The micro fractures in the Crush Zone produce a white-wash (rock dust) in the half cast. b. Transition Zone: This zone consists of micro fractures that connect and form macro fractures, both radially and parallel to the tunnel wall. The macro fractures are caused by the gas expansion during the detonation of the explosive; it increases the pressure in the (micro) fractures and creates the macro fractures. Seismic reflection, rock slicing and core drilling can be used for the examination. c. Progressing Zone: In this zone the existing radial fractures propagate due to the increase gas pressure inside these macro fractures. Examination methods are seismic reflection, rock slicing and core drilling. In addition, the Peak Particle Velocity (vibrations) could be used to estimate the depth (Tesarik et al. 2011)."

Jan 1, 2016

By Kuda R. Mutama, Allen E. Hall

A wind tunnel investigation into the fundamental characteristics of jet fan performance is described. The effects of varying fan positioning in a square tunnel cross section are reported for two fan outlet diameters and velocities. Tests were conducted, also for a jet fan placed in a flow developed by an external fan operating in the same direction as the jet fan. The position of the jet fan relative to the tunnel walls was found to affect its performance. Performance parameters were determined and used to formulate theoretical equations based on momentum and energy considerations. The results identified a range of flow ratios which can be used to design an effective jet fan ventilation system and provide a basis for the selection of jet fans for practical mining applications

Jan 1, 1997

By Richard Louis Viner, William D. Leech, Walter A. Mergelsberg

With the construction management team established and a full funding agreement secured the Washington Metropolitan Area Transit Authority (WMATA) now has the manpower and the financial resources to continue Metrorail construction into the 1990's. This paper describes WMATA's new role as construction manager after the transition from Bechtel Associates and gaining the full funding agreement with the Urban Mass Transit Administration (UMTA) and regional governments to complete 84.7 Metrorail miles (136km). The authors review the most recent station and line tunneling projects. WMATA's contractors have employed the state of the art soft ground and hard rock tunneling equipment and methods - an earth pressure balance TBM, a closed face TBM, and the New Austrian Tunneling Method (NATM). In final, the paper previews future underground work to be let under the funding agreement.

Jan 1, 1987

By A. P. Sasmito

It is well known that underground miners are exposed to one of the most dangerous working environments on earth. As mine delve deeper, the geological factor, mine position and climate condition as well as heat generation from mining machine give rise to the mine operating temperature. This, in turn, has an adverse effect on the environment and thus leads to higher operating costs. Careful estimation and design of air flow rate, spray system, cooling load and additional ventilation auxiliary equipment are of importance to ensure safety, comfort and productivity whilst maintaining low operating cost. A computational fluid dynamics simulation approach is employed to examine underground mine ventilation in a 36 m cul-de-sac of tunnel of coal mine. The model predictions in the turbulent range were validated by comparison with published data. Different turbulence models were tested to select one that yields adequate accuracy and is computationally efficient. Effects of the following parameters are evaluated: tunnel geometry, air flow rate and inlet air temperature. The objective of the simulation is to arrive at an optimal strategy for ventilation and thermal comfort at low cost.

Aug 1, 2013

By W. Schubert, N. Radoncic

"The term “squeezing” is frequently used, although it is ill defined. Definitions like “large and long lasting displacements” raise the questions about the threshold values for the magnitude and duration of displacements. Large displacements during tunnelling frequently are observed in fault zones with high overburden. Whether this causes problems very much depends on the design approach used. On the one hand, the magnitude of expected displacements has to be predicted prior to excavation to provide for enough allowance for the displacements without violating the clearance profile. On the other hand, the support characteristics must be compatible with the expected imposed strains. As the magnitude of the displacements and thus the strains in the support depend on the support capacity and its characteristic (yielding potential), only well engineered systems will be successful.Experience in Alpine tunnels over the last decades has shown that closed shotcrete linings can sustain a strain of approximately 0.8% to 1% without failure. Any strain above this value inevitably leads to failure of the lining, and thus a loss of resistance, causing additional displacements. Based on a large number of simulations, a criterion for a critical overburden depth up to which closed linings can be used has been developed. Traditionally open gaps in the shotcrete linings have been used to allow for larger strains. To enhance the efficiency of the linings, yielding elements have been developed, which are integrated in the shotcrete lining, allowing large strains and controlled development of support resistance (Figure 2). When designing such yielding support systems, the development of the displacements, as well as the rheological behaviour of the supports must be considered. As the development of displacements to a large extent depends on the face advance, also the advance rate has to be considered, to be able to compare the time-dependent strength of the lining to the stresses developing as a result of the imposed strains. Another issue is the compatibility of the rock bolts with the large strains. With standard grouted bolts, there is a potential that the “fresh” grout is sheared due to the initially large strain rates. Special rib designs of the bolts allow for a higher strain tolerance.For successful tunnelling through fault zones quality monitoring and up-to-date data evaluation is of crucial importance. With advanced evaluation tools, changes in the ground conditions ahead of the face can be reliably predicted. With the help of empirical relations, the development of the displacements for different advance rates and supports can be predicted, allowing for the determination of the required overexcavation.The paper presents a review of the development of ductile elements, methods of analysis, and monitoring data interpretation."

Jan 1, 2015

By Z. T. Bieniawski

Geomechanics signifies the science and engineering of soil and rock materials and of rock masses. It is a field of professional practice and research that draws heavily on the elements of soil and rock mechanics. Geomechanics contributes to a number of disciplines: mining engineering, civil engineering, geological engineering, petroleum and natural gas engineering, and engineering geology (including the elements of geohydrology and geophysics). These disciplines are involved in the design and construction of such projects as mines, tunnels, foundations for structures, excavated rock slopes, dams, shafts, boreholes, oil reservoir wells, underground storage facilities for oil and gas, and hazardous waste repositories. Geomechanics allows us to improve both our environment and our quality of life. In the context of this Handbook, the scope of geomechanics is discussed mainly from the point of view of applications to mining engineering. However, the coverage of the subject mate¬rial is so comprehensive that it is relevant to other disciplines as well. Section 10 covers the field of geomechanics in a structured fashion, beginning with the fundamental principles and leading into practical applications in mining engineering. Throughout the treatment of the subject, knowledge of geologic conditions is assumed since this is discussed in other sections of the Handbook. An important feature of this section is a series of practical examples illustrating the various aspects of geomechanics. Since geomechanics is concerned with both soil and rock mechanics, Chapter 10.1 introduces the fundamentals of soil

Jan 1, 2008

By C. Zhou, R. Jacksha

This paper reports measurement results for radio frequency (RF) propagation around 90° corners in tunnels and underground mines, for vertically, horizontally and longitudinally polarized signals. Measurements of signal power attenuation from a main entry into a crosscut were performed at four frequencies — 455, 915, 2450 and 5800 MHz — that are common to underground radio communication systems. From the measurement data, signal power loss was determined as a function of signal coupling from the main entry into the crosscut. The resultant power loss data show there are many factors that contribute to power attenuation from a main entry into a crosscut, including frequency, antenna polarization and crosssectional entry dimensions.

Jan 1, 2016

By D. Symonds, A. J. Richins, M. G. Nelson

Mining activities at Kennecott and Park City are similar in that both districts began operation in the last half of the 18th century, and both operated on a large scale for many years. However, they are different for two important reasons. First, the mines in the Park City district were always underground. The city of Park City was above many of those mine workings. It remained in place after mining activity stopped, and as the town became an up-scale ski resort, property values increased and the tailings dumps became desirable building sites. In contrast, Kennecott eventually became an open pit mine, and the growing pit effectively consumed many of the small towns that had grown up around the underground workings. Even towns on the periphery of the open pit were razed to allow for the disposal of mine overburden. Second, almost all mining activity stopped in Park City in the early 1970s, just as the first rigorous environmental legislation in the United States was enacted. (The Ontario mine operated sporadically until 1982.) Many mine structures, waste dumps, tailings ponds and piles, and tunnels were simply abandoned as the mining companies ceased business or were bought out. Kennecott, on the other hand, has been in continuous operation for more than 120 years, so a closure plan hasn’t been finalized. Nonetheless, environmental and social problems have arisen, and the company has had to address them.

Mar 2, 2022

By S Kost, R Nievergelt, F Cortes

In recent years, the use of steel fibre-reinforced concrete (SFRC) for segmental tunnel linings has become increasingly popular due to numerous advantages including durability, resistance to spalling, reduced cracking at corners and edges and significant cost-saving potential. One of the key parameters for measuring the performance of SFRC is the residual (post crack) flexural strength. A problem often faced in design and quality control of SFRC is the high variability of results obtained by standard beam test methods, with reported coefficients of variability (CoV) in the order of 25 per cent. The high test variability results in a relatively low permissible design strength relative to the average flexural strength of the material and commonly leads to non-conformances with respect to residual flexural strength during production testing.This paper presents the implementation of an alternative testing method using large round determinate panels (RDPs) for quality control testing of the SFRC used in the segmental lining of the City East Cable Tunnel (CECT) in Sydney. The alternative RDP test method was found to correlate well with standard beam tests and significantly reduce the variability of test results, minimising the risk of outlying residual flexural strength results, with zero non-compliant test results reported during the production period.This successful implementation of an alternative test for post-crack flexural strength with lower variability in results constitutes a relevant precedent to demonstrate the feasibility of this approach which contributes to the development of more cost-effective concrete mixes and minimises the risk for non-compliant results and the contractual disputes that commonly arise from these.CITATION:Cortes, F, Nievergelt, R and Kost, S, 2014. Development of a segmental lining specification for steel fibre reinforced concrete flexural strength testing using round panel tests, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 461–468 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Robert Essler, Paul Marsden, Paul Pandrea

"1. THE VICTORIA STATION TRANSPORT HUB Victoria Underground station is part of the Victoria transport hub, which comprises one of London’s main train termini and a major bus station. At the Underground station, the District Line running in the older shallow brick tunnels dating back to 1868 cross the Victoria Line running in the lower tunnels, which were opened in 1969. After Waterloo, Oxford Circus and King’s Cross/St. Pancras Tube stations, Victoria is the most frequented station on the London Underground network and is used by over 80 million passengers per year. Capacity at Victoria Tube station has been inadequate for many years with passenger numbers steadily rising. Overcrowding is a constant challenge and the station has to be closed regularly during morning and evening peaks until sufficient trains pass through to clear the platforms. For this reason an extension has been debated since the 1990s. After intensive preliminary investigations and feasibility studies covering many variants, which included a large-scale jet grouting test to determine the applicability of this technology as a protective measure for the tunnelling works, the project was officially started with the Victoria Station Transport and Works Act Order (Secretary of State, 2009) effective on the 18th of September 2009. Following a competitive tender process a joint venture of Taylor Woodrow and BAM Nuttall were awarded the contract by London Underground, with their design being carried out by Mott MacDonald Ltd. Ensuring the busy station remained open to the public was a key requirement of the Victoria Station Upgrade. Jet grouting works, which were executed from ground surface, were also carried out while the station was fully operational 2. OVERVIEW The Victoria Station Upgrade aims to increase the capacity of the Underground station significantly and one of its major design objectives is to optimise the transfer between the Underground lines. In order to achieve this, the following new structures are currently under construction: •,A new North Ticket Hall •,Extension of the existing South Ticket Hall •,Nine new escalators •,Connecting tunnels between the North and the South Ticket Hall •,8 new lifts providing step free access to all platforms •,An improved connection between the rail/bus terminus and the Underground station As the elevation and geometry of the existing structures cannot be changed, the new structures need to be adapted to the existing structures (see Figure 1)."

Jan 1, 2016

By Daniel F. Meyer, William C. Paschen

INTRODUCTION The problems involved with moving millions of tons of rock are being addressed by nationally recognized tunnel contractors who have converged in Chicago over the past 5 years. This wealth of expertise has been needed to meet the risk and challenge of constructing the world's largest network of underground tunnels which in turn has required a dramatic advance in the art and science of tunneling. These pioneers, through innovation, adaptation, and hard work, have eliminated the one major concern of The Metropolitan Sanitary District of Greater Chicago - how to move 8 million tons of rock. The Metropolitan Sanitary District of Greater Chicago (MSDGC) serves 122 municipalities covering 866 square miles in Cook County, Illinois. Of these cities, towns, and villages, 53 have combined sewer systems. On an average of once every four days, these systems overflow about 4 million gallons of combined sewage and rainwater into the area's rivers and canals. The overflows occur at approximately 640 outfall locations of which 10% are owned by the MSDGC, with the remainder of the points belonging to various other municipal bodies. All those who own these "point" sources of pollution are in violation of Illinois State and Federal regulations. To enable its member municipalities to come into compliance with State and Federal law, the MSDGC is implementing its Tunnel And Reservoir Plan (TARP). TARP is a regional solution to the problem of combined sewer overflow in the metropolitan Chicago area. TARP will greatly reduce the pollution of area waterways by intercepting the combined sewage and rainwater carried in the existing sys-

Jan 1, 1981