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By J. C. May, G. M. Elliott, J. J. Brady

Increased clearance was required in two railroad tunnels that were built about the time of the Civil War. Clearance infringements, whether they be excavation tights or caused by ice accumulation, reduce tunnel serviceability. Achieving increased clearance often means disturbing the ground and old ground support structures. Access and transportation needs dictate how and when the work can be carried out, and strongly influence the design approach and the methods used by the contractor to execute the work. This paper explores the pertinent considerations of the owner, the designer, the field inspection team, and the contractor in bringing this project to a successful conclusion.

Jan 1, 1997

By J. W. Mahar, E. J. Cording, F. L. Gau

INTRODUCTION The Washington, D.C. rapid transit system (METRO) when completed will consist of 98 miles of double track rail. Fifteen miles will be tunneled in rock and 12 large underground rock chambers will be constructed at station locations. The University of Illinois is under contract to Metro to provide observations and instrumentation services in the initial phase of construction. The work is coordinated through DeLeuw, Cather & Co., the General Engineering Consultant to Metro. The program is designed to monitor construction conditions as well as to provide information useful for the design of future rock tunnels and rock chambers in the Metro system. This paper presents the results of observations in the rock tunnels constructed to date. Most of the observations are in a 5000-ft-long, 30-ft-wide, double track tunnel in downtown Washington, D.C. Observations were also made in single track tunnels, shafts, enlargement areas, and pilot tunnels, and are being made in a large rock chamber 700 ft long, 76 ft wide, and constructed at shallow depth in a schistose gneiss. One of the major objectives of the observational program was to determine the orientation and character of joints and shear zones and to evaluate their effect on support requirements for various tunnel orientations and configurations. The consistency of geologic features throughout the Washington area has made the results of the initial study applicable to evaluation of support requirements on future tunnel contracts. The first section of this paper summarizes the geologic conditions in the tunnel and their effect on overbreak and rock movement.

Jan 1, 1997

By A. J. Stewart, R. L. Shufflebotham, D. W. Ferguson, T. L. Page

The Inter-Island Tunnel is a 7.7 kilometer (25,160 foot) long by 3.5 meter (11.5 feet) diameter concrete lined tunnel through the Cambridge formation below Boston Harbor. Constructed as part of the Boston Harbor Project, this tunnel will bring untreated wastewater from the MWRA’s South System headworks facility at Nut Island in Quincy, MA to the new Deer Island treatment plant. A myriad of problems delayed the construction of the tunnel. These problems included salt water inflows of over 22,000 liters (5,812 gallons) per minute, a major fire in the access shaft, weak rock and soil collapsing on the tunnel boring machine, and hand mining operations.

Jan 1, 1997

By Thomas P. Kwiatkowski, Len Cobb, Christopher D. Orlandi, Judith H. Jones

The Inland System supplies raw water to the industrial and domestic users in the City of Birmingham, Alabama. The Inland System, which is nearly 60 years old, consists of an approximately 57.9m (190 feet) high earthen dam across the Blackburn Fork of the Black Warrior River, a 39.6m (130 feet) high reinforced concrete intake structure, a 1524mm (60inch) diameter Dresser coupled steel transmission pipeline, and various distribution lines extending into Birmingham. The Inland System was owned, operated and maintained by the Industrial Water Board (IWB) of the City of Birmingham, an agency of the city government, from 1958 until 1994. In 1994, the City of Birmingham consolidated all water and distribution functions under the Birmingham Water Works Board (BWWB). In 1988, the IWB determined that the Inland System had reached a point where its reliability could not be assured without an in-depth evaluation and renovation. The IWB engaged Christy/Cobb, Inc. (CCI) of Birmingham as its consultant for the renovation work. CCI evaluated the Inland System and submitted a report to the IWB in April, 1992. The report contained several recommendations for capital improvements to the system including increasing the emergency spillway capacity, reconstructing the fuse plug, relocating public access to the lake away from the dam area, constructing a new intake structure, and constructing a tunnel through the dam abutment to deliver the water from the proposed intake structure to the existing 1524mm (60 inch) diameter supply line. The new intake structure and tunnel would provide for a future maximum demand flow rate as well as provide bypass and level control capabilities. CCI was authorized in 1992 to proceed with the engineering design for the renovation of the Inland System with emphasis on the spillway and intake structure. PROJECT DESCRIPTION The major component of the renovation of the Inland System was the new intake structure and tunnel through the dam abutment. CCI engaged Jenny Engineering Corporation (JEC) of Springfield, New Jersey as a consultant for the tunnel design. JEC was responsible for the design of the tunnel, the connecting shaft between the intake structure and tunnel, and the steel pipe final lining, while CCI was responsible for the intake structure and the connection to the existing supply pipeline as well as overall project management. CCI and JEC evaluated the project site in order to select the location for the new intake structure and set the alignment for the tunnel. A factor in the evaluation process was that the level of the lake could not be lowered to construct the new intake structure since the supply of water from the Inland System had to maintained. Therefore, a location was required which was

Jan 1, 1997

By Lewis L. Oriard

Near the village of Villarino de los Aires, in the province of Salamanca, Spain, was an existing underground hydroelectric power plant. A major enlargement was undertaken to increase the electrical generating capacity, under a contract awarded to a joint venture of Dragados y Construcciones, S. A. (Spain), Entrecanales y Tavora, S. A. (Spain), and S. A. Conrad Zschokke (Switzerland). The enlargement required the excavation of a large and complex underground system of tunnels, shafts and chambers adjacent to existing facilities and interconnected with these facilities. The existing machine hall and transformer chamber were both extended, requiring the blasting of the existing end walls. The drilling, blasting and excavating of the underground system had to be done without damage to existing underground chambers and tunnels, or any of the existing structures, equipment or instrumentation facilities, often within just a few feet of the blasting. This required careful control of vibrations, airblast overpressures and dust.

Jan 1, 1997

By Harry Sutcliffe, George B. Wallace, Madan M. Singh

INTRODUCTION Several recent estimates have predicted that the extent of underground tunneling in the future will far surpass past records. It is also emphasized that the expected increase depends largely on the cost of tunneling and hence every effort should be made to reduce this price. The largest items of expense in some tunneling programs are not related to the technical problems encountered but rather the human factors involved in contracting and executing the project. In order to examine the mutual interactions between the groups involved in tunnel programs, the Engineering Foundation sponsored a conference on "Owner-Engineer-Contractor Relations in Tunneling", July 12-16, 1971 at Deerfield, Massachusetts. The meeting was cosponsored by the Associated General Contractors of America and the Construction Division of the American Society of Civil Engineers. The seminar was attended by representatives of contractors, owners, and engineers who drafted and approved a set of recommendations based on the ideas generated during the discussions. It was also suggested that the resulting document be given as wide publicity as possible amongst the underground construction community. The First Annual Rapid Excavation and Tunneling Conference provides an excellent forum for this presentation.

Jan 1, 1997

By Brock H. Morrison

One of the major criterion of any mechanised tunnelling operation is to minimize downtime of the tunnelling machine by employing the most efficient muck handling system space and economic factors permit. A tunnelling machine which remains idle during a large percentage of the available shift working time is a luxury no contractor can afford. There are several possible reasons for non-productivity of a tunnelling machine ... the inability of the muck handling system to keep pace with the tunnelling machine on a continuous basis is one major cause. In large diameter tunnels, where several trains or more than one muck hauling unit can operate simultaneously, downtime of the tunnelling machine may be kept to an acceptable level. On small to medium diameter tunnels, 8 feet to 14 feet in diameter, the muck removal support system is normally restricted in capacity, resulting in an excessive tunnelling machine downtime as the tunnel extends from the shaft. There is a need for an efficient, continuous and economical muck removal system for small to medium size tunnels being driven by a hard rock machine. This paper is intended to provide an insite into pneumatic conveying, and explain the Radmark System; its development and utilisation in the tunnelling and mining fields. STATE OF THE ART Pneumatic conveying is the transportation of bulk materials

Jan 1, 1997

By Pierre Mousset-Jones, Felipe Calizaya

This paper summarizes the current research trends in the ventilation design for the construction of very long tunnels, and presents the results of leakage flow measurements in three auxiliary ventilation systems. The study includes an estimation of an important design parameter, namely, the leakage path resistance, and a discussion of its effects on the overall efficiency of a ventilation system. A sample problem is used to illustrate the calculations.

Jan 1, 1997

By Joseph Fernandez, Luminita Calin

INTRODUCTION The Tunnel and Reservoir Plan (TARP), commonly known as the Deep Tunnel Project, is the daring and unique concept developed by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) as a two-phase solution to the problem of waterway pollution and basement flooding due to sewer system backups created by the combined sewer over-flows (CSOs). Phase I, primarily for pollution control, includes the tunnels, shafts, connecting sewers and structures. These Phase I facilities intercept, during wet weather events, the CSOs within the MWRDGC TARP service area. The tunnels and shafts provide temporary storage of the CSOs for subsequent treatment at Water Reclamation Plants (WRP) before discharging into waterways. Ultimately, upon completion of Phase II, the tunnels, located from 45 m(150 ft) to 100 m (330 ft) below ground, will convey the CSOs to reservoirs for storage until WRP capacity is available. Phase II, which includes the reservoirs, pumping facilities, additional tunnels and shafts, has been planned to serve a dual purpose. The reservoirs provide storage of excess flows during wet weather events, those beyond the WRP capacity. Following the wet weather events, the stored flows can be conveyed, at controlled rates, to the WRPs for full treatment. These excess flows previously would have resulted in both overflows into the waterways and eventually backups in the local sewer systems. The storage capacity of the reservoirs also will promote the full utilization of the conveyance capacity of the tunnels and shafts, which in turn results in optimizing the conveyance capacity of the existing sewer systems. Therefore pollution control is further enhanced by allowing for capture of a greater volume of CSOs and greatly minimizing backups in the local sewer systems. The TARP project consists of four systems: O’Hare, Mainstream, Des Plaines, and Calumet, covering a total area of 971 km2 (375 mi2) and serving the City of Chicago and 51neighboring communities as shown in Figure1. With only two contracts left before completion of the Phase I tunnels, the 12.7km (7.9mi) Torrence Avenue leg, to be awarded in 1997, and the 12.4km (7.7mi) Little Calumet leg unfunded as of yet, both part of the Calumet System, the pollution control phase of the project is now 86% complete (Table 1).

Jan 1, 1997

By J. J. K. Daemen, C. Fairhurst

Two aspects of tunnel support design are considered, and for both particular attention is paid to the influence of rock failure around the tunnel on the loads developed on the supports. 1) In general it has not been possible to extend analytical methods for the study of rock failure around tunnels to three dimensions. As a consequence it was not possible to calculate either the influence of the face or the actual sequence of support loading as the face advanced. The finite element method made this extension possible. A simplified analysis of the influence of the face and of the sequence of support installation has been made. The influence of the original stress field and of the rock behaviour on the length of tunnel which can be left unsupported (related to the stand-up time) is shown. The degree to which a 2-dimensional analysis can be used to approximate the final support load is shown to be dependent upon the post-failure behaviour of the rock. 2) Tunnel support design requires a knowledge of the forces and of the -rock displacements which cause stressing and deformation of the support system. A 2-dimensional model incorporating a detailed representation of several support systems, of the rock behaviour in the broken zone and of the interaction between rock and support is given. The model allows the calculation of the stress distribution in the support. The significance of the relative stiffness of support and rock on the stresses developed in the support is shown.

Jan 1, 1997

By David J. Leeds

Increased interest in the utilization of the underground environment for water conveyance tunnels, vehicular tunnels, room and pillar type storage chambers, and military installations has focused attention on the possible effects of seismic activity on the stability of these types of structures. Earthquake experience has generally been related to the seismic stability on the surface of the earth. To establish aseismic design criteria, we attempt to predict the seismic exposure of a given site, both in terms of the spectrum of motion to which the structure must react favorably, and the recurrence rate of that motion. Experience gained from studying the effects of the Plowshare underground nuclear tests on existing tunnels and mines, coupled with the experience of the behavior of tunnels and mines in earthquake regions, provides us with an insight to predict the possible effects of earthquakes on underground openings and to establish design criteria. The type of damage ranges from minor fracturing and movements along pre-existing joints or faults through deformation of openings to collapse. The methods used to establish the seismic design criteria for an underground opening require modification of surface criteria to account for the difference in both amplitude and spectra underground. An aseismic evaluation should be performed on all important projects in areas exposed to possible earthquake motion. To perform this evaluation, information is required pertaining to the geometry and properties of structure and ground. Dynamic as well as static properties are required. A prediction of performance can be derived by exposing a model of the site, expressed in terms of its properties and geometry, to a design earthquake.

Jan 1, 1997

By Håkan Schunnesson, Kirsten Holme

"When mining high grade, narrow ore bodies, the mining method often implies a very detailed knowledge of the ore contacts to avoid unacceptable ore loss and waste rock dilution. During the past decade, the use of microprocessor based drill monitoring equipment has become an accepted technique, even for percussive drilling. On the basis of the recorded drill performance, such as penetration rate, torque pressure, thrust etc., a fast evaluation of the lithological sequence of the ore zone can be made. In order to evaluate the potential of percussive drill monitoring to pro-vide detailed information of the geometry of the ore body, the technique was tested in the Viscaria copper mine in Sweden during 1996.To provide understandable information to the mine geologist, great emphasis was placed on the separation between the drilling response generated by variations in rock conditions from variations caused by the operator and the drill system. Due to the complicated geology in Viscaria, the drilling response presented to the geologists was separated in two independent signals, one representing the hardness of the rock and one representing the in homogeneity(fracturing) of the rock. With those signals a good separation between different rock types in the ore horizon was achieved.The experience from the Viscaria copper mine is that drill monitoring not only can be used to locate contacts between rock types, but also to characterize rock conditions and, often, also to specify the exact rock type present. Because it is possible to get the drill monitoring information very quickly it is a valuable complement to diamond drilling for increasing the specific knowledge of the geology and the ore body."

Jan 1, 1997

By J. Esson, R. A. D. Pattrick, M. K. Nimfopoulos, D. A. Polya, K. M. Michailidis

"Abstract-Economic Mn-oxide ore deposits of commercial grade occur in the Rhodope massif near Kato Nevrokopi in the Drama region, Northern Greece. The Mn-oxide mineralization has developed by weathering of continental hypogene rhodochrosite-sulphide veins. The vein mineralization is confined by tectonic shear zones between marble and metapelites, extending laterally into the marble as tabular, pod or lenticular oreshoots (up to 50 m ?? 20 m ?? 5-10 m). Supergene oxidation of the hypogene mineralization led to the formation of in-situ residual Mn-oxide ore deposits, and secondary infills of Mn-oxide ore in embryonic and well developed karst cavities.Whole rock geochemical profiles across mineralized zones confirm the role of thrusts and faults as solution passageways and stress the importance of these structures in the development of hydrothermal and supergene mineralization at Kato Nevrokopi. Three zones are recognized in the insitu supergene veins: (A) a stable zone of oxidation, where immobile elements form (or substitute in) stable oxide mineral phases, and mobile elements are leached; (B) a transitional (active) zone in which element behavior is strongly influenced by seasonal fluctuations of the groundwater table and variations in pH-Eh conditions; and (C) a zone of permanent flooding, where variations in pH-Eh conditions are minimal. Zone (B) is considered as the source zone for the karst cavity mineralization. During weathering, meteoric waters, which were CO2-rich (PCO2 ~10-3.8 to 10-1.4) and oxygenated (fO2 ~10-17 for malachite), percolated downward within the veins, causing breakdown and dissolution of sulfides and marble, and oxidation of rhodochrosite to Mn-oxides. Karst cavity formation was favored by the high permeability along thrust zones. Dissolved Mn2+ was transported into karst cavities in reduced meteoric waters at the beginning of weathering (pH~4-5), and as Mn(HCO3)2 in slightly alkaline groundwaters during advanced weathering (pH~6-8). Mn4+-oxide precipitation took place by fO2 increase in ground waters, or pH increase by continuous hydrolysis and carbonate dissolution. In the well developed karst setting, some mobility of elements occurred during and after karst ore formation in the order Na>K>Mg>Sr>Mn>As>Zn>Ba>Al>Fe>Cu>Cd>Pb."

Jan 1, 1997

By Pieter Barendsen

INTRODUCTION One of the main problems in tunneling without the use of explosives lies in the development of tools which, at an economically acceptable level, are capable of continuous breakage of the rock, resulting in a fragmentation suitable for a smooth, uninterrupted transportation of the muck away from the tunnel face. Tools employed on tunneling machines have, so far, always been of the mechanical kind which break up the rock by a crushing and shearing action. Other methods of rock breaking are possible but, even if some of them have reached the laboratory testing stage, nearly all of them are still too "exotic" to be of any practical use in the immediate future. One must admit, however, that some highly interesting results are beginning to be reported from the USA on the use of high pressure water jets for the destruction of rock through erosion, a field pioneered in Europe(USSR and Great Britain). Mechanical breakage of the rock is effected by inducing stresses exceeding its compressive/shear strength, by loading it with a wedge of cone shaped tool, until cracks are formed and chips loosened. In order to allow the tools to act upon the rock face continuously, they are commonly shaped as rotating bodies, "roller bits" or "disc cutters", spinning freely and mounted on a revolving boring head of tunnel diameter. The thrust of the tools against the face is generally exerted in a direction which is parallel to the tunnel axis.

Jan 1, 1997

By R. L. Schmidt, Williamson. T. N.

INTRODUCTION This paper describes one of several research projects funded by the Advanced Research Projects Agency to extend the technology of rapid underground excavation. This study and field research effort are to investigate alternative means to determine rock and geological conditions in advance of a tunnel boring machine (TBM). Approximately 1 year of a planned 3-year program has resulted in the definition of three candidate drill systems. Hardware has been assembled to field test these candidates and testing has begun. The 3-year objective is to develop a single optimum prototype drill and test it in an active TBM operation. ACKNOWLEDGMENT This research was supported by the Advanced Research Projects Agency (ARPA) of the Department of Defense and was monitored by the Bureau of Mines under Contract No. H0210037. The authors and sponsoring agencies are indebted to the quarry operators in California, Virginia, and West Virginia who offered assistance including access to their properties.

Jan 1, 1997

By Taira Emoto, Hikozou Imaoka, Sohta Takatsu, Takeshi Suzuki, Yoshihito Minami

An Oval Section TBM (tunnel boring machine) enables excavation of tunnel with elliptical cross section by inclining the cutterhead. It is developed to utilize the proven conventional TBM technology with minimum modifications. Various types of tunnels which are preferred to have non-circular cross section can be economically excavated, reducing both overbreak and the amount of muck produced. On the other hand, an inclined cutterhead may create a number of new problems, such as in excavation efficiency and steering that are unknown in excavation works using a circular TBM. This paper reports on verification tests carried out to examine the extent of such problems using experimental models of the machine in an attempt to confirm the feasibility of the Oval Section TBM.

Jan 1, 1997

By Yasutaka Izumi, Tuneyoshi Funasaki, Keizou Miki, Makoto Kanai

INTRODUCTION The Tokyo metropolitan region, inclusive of the three neighboring prefectures (Kanagawa, Chiba and Saitama), has the highest concentration of population and industry in Japan; with an area of 13,500 km2 or only 3.6 percent of the national land, but a population of 31.8 million or 26 percent of the national total, and a Gross Regional Product (GRP) of146 trillion yen (US$1.33 trillion) or 36 percent of the overall GDP of Japan as of 1990. Tokyo Bay, embraced by the metropolitan region as shown in Figure 1 (a), (b), is open to the Pacific Ocean as a marine gateway and is ringed by large cities and coastal industrial zones together with port facilities, all constituting a concentration of prime importance for socio-economic activities. The Trans-Tokyo Bay Highway (TTB highway), which crosses Tokyo Bay and provides a direct transportation link between the west and east sides of the bay, has long been a sort of “dream-come-true” project in Japan. As shown in Figure 2, linked to the Tokyo Bay Shore Highway, Metropolitan Inter-city Expressway, Tokyo Outer Ring Road, Tateyama Express-way, and others, it will play an important role as an integral part of the regional highway network to help promote spatial redistribution and multi polarization of urban functions, thus strengthening cooperation between cities and restructuring the metropolitan region. The TTB Highway is a project of 15.1 km in length designed as a toll highway to cross the bay by tunnel and bridge, and will require ten years to complete at a total cost of more than 1,438 billion yen (US$13.077 billion). Following more than 20 years of feasibility and environmental assessment studies, construction of this giant offshore highway project commenced in May 1989 as the first large-scale highway project with private-sector participation under the prevailing Road Law in Japan, and is now steadily proceeding toward the goal of completion in fiscal1997. This report outlines the entire TTB Highway project, including the waterproofing measures against high water pressure and the rapid construction method applied in the construction of shield tunnel sections.

Jan 1, 1997

By Thomas Sisley, Jozef Zurawski, Richard Switalski

Hilltop Interceptor Contract G is one of the segments of the wastewater control system in the greater Cleveland area. The tunnel is a relief interceptor constructed by the Northeast Ohio Regional Sewer District to minimize combined sewer overflows in the Easterly Service Area. The design study identified the need for a 3.35 m (132 in) diameter, 3.35 km (11,000 ft)in-line storage conveyance tunnel to be constructed at depths of 30 to 70 m (100 to 230 ft).Six structures for access, future flow drop, work shafts and overflow control were required to complete the system. The interceptor reduced the design peak flow from 12.5 m3/s(285 mgd) to 6.1 m3/s (140 mgd) by detaining in line 22,800 m3 (six million gallons) of wastewater.

Jan 1, 1997

By Fredrick J. McGarry, Fred Moavenzadeh

In order to reduce the resistance of hard rocks to excavation by the available cutters, and in order to reduce the wear of the cutters and thus to increase the efficiency of the conventional tunneling machines and to improve their rate of advance in hard rocks, surface active agents have been studied in the controlled laboratory environments and have been experimented with in the field of actual tunneling operations. The laboratory study utilized a notched beam test to measure the effectiveness of 30 different surface active agents on the amount of surface energy required to cause stable fracture in the rock specimens. In addition to the type of rocks, geometry of the specimens, type of surface active agents, the effects of environmental factors such as temperature and degree of saturations were studied. The principle mechanism responsible for weakening of rocks in the presence of surface active agents was believed to be that of stress activated corrosion. The application of surfactants in the laboratory resulted in a reduction of up to 50% in rock strength, while limited experiments in the field have shown a 10 to 20% increase in the rate of advance. Substantial efforts both in the laboratory and in the field are needed to fully understand the mechanism involved and to utilize the effectiveness of surfactants as weakening agents for hard rocks.

Jan 1, 1997

By Joseph Irons, David Westfall

Three rock tunnel sewer systems are underway in the Chicago Area. (Figure 1) The three are designed to act independently and to be later connected to the future tunnels of the master plan. The tunnel excavation for each of the systems has been completed. One is in the Northwest area within the City being built by the City, known as the Lawrence Ave. System. Another is in the Southwest suburbs, known as the LaGrange-Brookfield Sewer or Southwest 13A, being built by the Sanitary District, the third is in the South suburbs called the Crawford Avenue sewer or Calumet 18-E, Ext. A- being built as a joint venture between the City and the District. The three are similar in that they have the same purpose, the same component parts and their tunnels were constructed in the nigaran limestone using a mechanical mining machine. The purpose of each of the systems is two-fold. First to provide flood relief for existing inadequate sewer systems, and second to reduce the pollution load to the waterways caused by combined sewer overflows. The existing systems in the areas to be relieved are combined sewers built many years ago. The main outlet for the Village of LaGrange, for example, was built in 1908, is badly in need of repair and lacks the capacity to handle the flood flow from the heavily urbanized area it now serves. The dry weather flow from the area is taken off by intercepting sewers. However during

Jan 1, 1997