Search Documents

By Jeffrey Peterson, John Beesley, Martino Scialpi, John Cassidy

The DC Clean Rivers Project is DC Water's ongoing program to capture and treat combined sewer overflows (CSOs) during rainfall before they reach the District waterways. The Anacostia River system was designed to reduce CSOs into the Anacostia River and includes the Blue Plains Tunnel, Anacostia River Tunnel, First Street Tunnel, and Northeast Boundary Tunnel. A portion of the Anacostia River system was commissioned in March 2018 and the final component, the Northeast Boundary Tunnel, was placed in operation on September 15, 2023. This paper provides a summary of the experience gained during construction of this +$2.9 billion project, an overview of the system performance since its activation in 2018, and a look-ahead to the next phase of the DC Clean Rivers program: the Potomac River Tunnel.

Jun 23, 2024

By Verya Nasri, Mehdi Bakhshi

The development of the Montreal metro extension Line 5 -Blue Line- toward the northeast are located between the existing Saint-Michel station and Anjou. It consists of 6-km long two-track tunnel, five new stations and six auxiliary structures. Most of the tunnel (5.5 km) will be excavated by a 9.6 m diameter shielded rock TBM and supported by a precast segmental lining system. TBM will be fitted for probing and preexcavation grouting to control water inflow into the tunnel during the excavation. This paper presents major design aspects of the TBM tunnel including alignment, geological condition, spaceproofing, precast segmental lining, and geotechnical instrumentation and monitoring.

Dec 1, 2022

By Gerd L. Klinkenborg

Throughout the history of the development of mechanical conveyor systems, it has always been an established condition that loads are received at one end of a single-belt conveyor and discharged at the other end, in a point-to-point, manner. In systems designed for the continuous transport of granular materials, vertical or horizontal changes in; direction have always necessitated two or mope single-belt conveyor units, with a corresponding number of motors, assemblies and attendant mechanical and human or electronic controls. Besides these high-cost factors, every change in the system's direction also calls for a transfer point that involves a drop-back of the material from one level to another with some loss of the material and, in many cases, unwanted additional granulation. Where changes in the location of the discharge point are wanted, the conventional single-belt conveyor must either be replaced by a shorter or longer unit or additional units purchased and installed, or existing units rearranged. This can take days or weeks, and involve special expenditures as well as loss of valuable production time.

Jan 1, 1962

By Daniel Saramak, Agnieszka Saramak

A big issue in crushing and grinding operations in raw materials handling is high energy consumption and low breakage effectiveness. According to the Legendre [7], only 10% of energy input is directly consumed on the feed material breakage, while the remaining portion is dissipated in the form of heat and noise [8]. In the industry of limestone powder production, the grinding operations constitute integral part of technological circuits, and the energy consumption in operations of industrial comminution consume as high as 2% of world energy [14]. High-pressure grinding is the technology with proved energy benefits both in ore processing circuits and in limestone grinding. The promising results concerned mostly the achieved energy savings and good results of material breakage were achieved and demonstrated in numerous investigations [1,3,12]. However, it appears that a proper selection of operational parameters of the press devise, determination the feed material characteristics and adjustment of process course san be of a key-significance in improving an effectiveness the HPGR operation. Operational parameters of devices and process course should be verified towards the characteristics of the feed material, which mainly applies to the particle size and shape of the feed material and its moisture, and also mineralization in case of ores [2,4,9]. There are various investigations concerning an impact of the operational pressing force on comminution results which mostly refer to the determination of energy consumption and crushing ratio [5,6,10,13]. Investigations on the moisture content are less common, however their results suggest that, in general, the HPGR feed with higher moisture shows the tendency to higher comminution intensity, while the energy consumption increases together with increasing of feed material moisture. Investigations on olivine sand feed [11] showed that crushing ratio decreases for higher moisture, especially when the material is crushed at higher pressing force. HPGR devices, however, shouldn’t be regarded as a unique and perfect solution for comminution of each type of material. But they indeed may bring technological and economic benefits, comparing to conventional crushing and grinding machines, resulting in more favourable breakage of material particles and lower consumption of energy per unit mass of processed feed material.

Feb 1, 2025

By G. Vogt

Water is one of the most important ressources of our planet. Unlike many other natural resources, water cannot be substituted by anything and must therefore be handled with the utmost care. Depending on the region and the possible shortage of water, the importance of water increases even further. Water consumption is not the only factor. In the construction industry, water pollution from auxiliary and operating materials and processes as well as other contaminants and their resulting load on wastewater play an important role. The sources for wastewater on tunneling construction sites are various: Washing water, seepage water accumulating in construction pits, tunnel water, water used in the slurry circuit in fluid-assisted tunneling methods or water from concrete work and stone cutting all these waters are contaminated with a range of pollutants like solids, hydrocarbons, heavy metals, etc. These contaminants can be removed or treated/reduced with the help of specifically designed wastewater treatment plants (WTPs). After the treatment the cleaned water can be either, in best case, reused on the construction site itself or discharged into water utilities like the available sewer or river pin respecting their discharge requirements. Due to dwindling water resources globally, the continuously rising discharge limits and the ever more important aspect of sustainability the use of WTPs on tunneling construction site will be indispensable. In this paper, it will be presented how these systems are designed and work, what advantages they offer environmentally as well as financially and what to look out for when planning and implementing such a system onto jobsite.

Jun 23, 2024

By John Kuyt, Zili Li, Michael Mooney, Michele Mangione

"INTRODUCTIONTwin bored tunnels are commonly used for a variety of road and tunnel projects throughout the world. A major component of these twin tunnel projects is the construction of connecting cross passages that provide emergency access between tunnels and space for tunnel service equipment. Cross passages can present significant geotechnical risk and technical challenges to a project – support systems must be considered for redistributing loads around the mainline tunnel openings and supporting new loading resulting from excavation activities. Additionally, cross passages pose risks to construction schedule and cost because of their sequencing at the end of construction, so mitigation of schedule overruns can be critical. By observing field instrumentation data records from completed projects, a betterunderstanding of the force development in each temporary structure can be achieved with indication of which structures are the most critical to support ground loads.This paper discusses the data obtained during the Brisbane Airport Link construction project, a road tunnel located in Brisbane, Australia. Strain gauge instrumentation data from the precast segmental lining and propped opening steel sets is presented with relation to the construction sequence and local geology. Interpretations and conclusions based on the observed trends are proposed, with several key mechanisms affecting the loading and unloading identified.Brisbane Airport Link Project OverviewThe Brisbane Airport Link project in Brisbane, Australia, connects central Brisbane to the airport located northeast of the downtown with over 7km of twin-bore road tunnels, two lanes each, with several caverns, interchanges, and access ramps constructed along the alignment to connect to other key routes in the city. The project was executed under a Public-Private Partnership (P3) scheme, funded and operated by the consortium BrisConnections. The main contractors were a joint venture of John Holland and Theiss, while the design was carried out by Arup and Parsons Brinckerhoff.Construction of the tunnels was conducted using a combination of 17 roadheaders and two 12.5m double-shield Herrenknecht TBMs [1]. The TBMs were used in EPB-type closed mode for the initial portion of their drive, starting at the northeast end of the alignment. Tunneling started in soft ground, weathered rock, and mixed face conditions initially, progressing to competent sedimentary rocks as the drive continued. Support was accomplished using a 12.1 m diameter steel fiber reinforced concrete (SFRC) segmental lining installed behind the TBMs in a 9 segments + 1 key arrangement. The innovative design of these segments is detailed in the paper by Harding and Francis [2]. Ancillary roads and underground interchange caverns were constructed by sequential excavation techniques using roadheaders, accounting for nearly half of the total underground excavations."

Jan 1, 2016

By Kyle Amoroso, Aaron K. McCain

Frozen soil shoring has been used for decades in the tunneling industry to provide temporary support of excavation for shafts and cross-passage excavations. However, horizontal penetrations through the frozen soil can prove to be challenging. The key to creating a stable portal through frozen ground is managing and mitigating groundwater flow into the excavation through the annular space surrounding the drill stem or casing. This paper will review different approaches that have been successfully used to penetrate frozen soil shoring on multiple projects.

Jun 13, 2023

By Fabrizio Fara

The Ship Canal Water Quality Project (SCWQP) includes a 2.7-mile long, 18'-10" internal diameter tunnel which is located inWest Seattle. Tunneling in urban areas and soft ground conditions (Till and Till-like soils in Seattle) is associated with the risk of settlements, especially in presence of groundwater above the alignment. The Designer foresaw the use of soil improvement (jet grouting) outside of the launch shaft to mitigate the risk of flowing ground and to provide a redundant sealing. The Contractor proposed and ultimately successfully executed a different approach by using a “Steel Bell System” or Pressurized Can as described in this paper.

Jun 13, 2023

By W. L. Dare

Land use planning is not a new concept in the United States but the emphasis has changed drastically since the early 1960's. Under the old interpretation we tried to expand our frontiers and develop our land, but as society has become more affluent and mobile the demand has grown to preserve those parts remaining undeveloped. There is something of a paradox inherent in this change of emphasis. While affluence has motivated our support to preserve the quality of the natural environment, industrial development is needed to support the affluence. Because we cannot accomplish all of each, sound planning and compromise will be necessary since it is unlikely that, the American people will want to surrender much of their life-style or their awakening environmental concern. Any industrial society, whether a goal reached or an aim yet ahead, is built largely on the use of mineral raw materials and energy, the physical base of nearly all activities and products. The standard of living which is important to us all is growing more dependent upon these minerals, metals, and energy fuels. Although reduction in consumption of raw materials may be acceptable to those at a certain economic level of a society, those who have not reached that level cannot be expected to accept a lowering of their present or anticipated standard of living.

Jan 1, 1974

By Trenton Cohen, Joseph McDivitt, Shimi Tzobery, Joseph Sinacori, Scott Zylstra

The 2-mile Beach Interceptor Sewer Tunnel was constructed in 1954 to then-current mining and construction standards. Due to its lifespan and deteriorating condition it is now being stabilized and rehabilitated using conventional excavation and ground support. At its southern end, below the prestigious Three Arch Bay community, the original tunnel alignment passes under a historic landslide where the tunnel was sand-backfilled and capped by bulkheads in 1957 due to severe and caving ground conditions. Video footage of the existing 21- inch clay pipe showed that the pipe is severely damaged, which could potentially cause a catastrophic pipeline failure and sewage spill into the Pacific Ocean. This paper summarizes the thorough investigation and design process, tunnel realignment construction and monitoring, and the notable cooperation between all parties to overcome the project risks.

Dec 1, 2022

By James H. Williams

More than 100,000 residents of Springfield and surrounding communities live on karst (sinkhole) terrain on the Springfield Plateau in southwestern Missouri. The city occupier much of the headwaters area of Wilson Creek basin, which is underlain by the Burlington Limestone (Mississippian), a cavernous, massively bedded formation averaging 150 feet in thickness. Sinkholes, some as deep as 75 feet, pock-mark the uplands. Stony red residual clay mantles the pinnacled limestone bedrock. Surface water lost to sinkholes and losing reaches of upstream areas resurges in springs and estevellas (reversible sinkholes) in the lower reaches of Wilson Creek. The Springfield Southwest Treatment Plant, an activated sludge process sewage treatment facility, situated about mid-basin at the confluence of Wilson Creek and a tributary, South Creek, serves the entire city. Effluent from the treatment plant together with industrial, street-wash and other waste from the-headwaters of the basin have degraded both surface and ground water quality in much of the Wilson Creek watershed. The area affected includes Wilson's Creek Battlefield National Park and recreational reaches of James River below the mouth of Wilson Creek.

Jan 1, 1970

By Robert G. Lundguist

REAM is a unique and promising method of rock breaking using high energy, inert projectiles to impart mechanical energy to the rock. This paper describes a demonstration of the application of this new technology to two specific problems in open pit mining: secondary breakage and the scaling of loose material from pit walls. Under previous government contracts, Physics International Company developed the projectile impact method for a large variety of commercial and military rock excavation tasks. A 4 meter (13 foot) diameter by 16.8 meters (55 foot) long tunnel was driven at the Hope Valley Mine in the Sierra Nevada mountains of California in 1972 and 1973. An average of 1100 kg (1 ¼ tons) of a 172 MN/m2 (25,000-psi) granodiorite formation was broken by each of 590 shots used to drive the tunnel.l Based on these results it is estimated that REAM can drive over 60 meters (200 feet) of tunnel per day at about 88 percent of the cost of drilling and blasting. In addition, repeated axial impact by high energy projectiles was used to drill a 0.4 meter (16 inch) diameter horizontal hole in the same granodiorite formation. Each shot advanced the hole an average of 0.2 meter (8 inches).

Jan 1, 1976

By H. C. Siebert

According to the "Survey of Energy Resources 1980" (1)*, which was prepared by the Federal Institute for Geosciences and Raw Materials in Hannover (FRG)for the World Energy Conference 1980 in Munich, the world coal deposits are assessed at 775 billion tce proven reserves 448 billion tce of them recoverable and 6 161 billion tce additional resources. If one ignores growth rates, the current world coal output of 2,8 billion tpy gives our recoverable reserves a static life expectancy of 175 years. With an average increase in world output of 3,2 % like between 1973 and 1980 this range would be further shortened to an alarming degree. Furthermore, the criteria used to distinguish between workable and unworkable resources give rise to the suspicion that deposit characteristics are not always taken into account to a sufficient degree. For example, little attention is paid to major ?Bonitaet" - factors such as dip and seam thickness. There have been wide-ranging scientific discussions on the lower limit for workable coal resources, but no such limits have been set at the other end of the scale. Otherwise it is well known that performance and costs are badly affected den in level and moderately inclined seams the seam thickness is more than 4 to 5 m, because special mining methods have to be used beyond this limit. These are associated with significantly higher costs than with the winning of seams of ?normal? thickness.

Jan 1, 1985

By Peter Johnson, David Barber, Lachlan Henderson

"The traditional approach to rail tunnel fire safety design is to follow NFPA 130, which assumes a major tunnel fire could occur and requires bi-directional emergency ventilation. There is no regard to the impact of ventilation on fire growth and smoke production. In Europe and other parts of the world, the need for tunnel ventilation systems to provide smoke management in the event of fire is being questioned. The European Commission’s Safety in Railway Tunnels TSI is based on a philosophy that improved running capability (preventing fires and other events stopping the train in the tunnel) and elevated fire performance of materials means the chances of a major fire in a tunnel is highly unlikely, with only small fires expected, and no tunnel ventilation required. This approach is reinforced by the International Tunneling Association which has recently published an Engineering Methodology for Performance Based Fire Safety Design on Underground Rail Systems, which includes a methodology that does not require assessment of tenability in tunnels, but requires a scenario based risk assessment to be undertaken to determine overall fire safety measures. Recent research by the University of Edinburgh has shown that forced airflow from a mechanical ventilation system may promote fire growth and increase smoke volumes much more than with natural ventilation. Whilst the concept of no mechanical ventilation (i.e. natural ventilation) is a new concept for some, for many rail tunnels it is worthy of serious further consideration. RAIL TUNNEL SMOKE MANAGEMENT AND STANDARDS Smoke management using mechanical bi-directional ventilation systems has been a central part of the fire safety design solution under NFPA 130 for rail tunnels since 1982. The current version of the standard, NFPA 130: 2014, states that mechanical ventilation should be fitted to rail tunnels of length greater than 305 meters and an engineering analysis should be undertaken for tunnels of length 61 to 305 meters to determine whether mechanical ventilation should be fitted. However, this approach is not necessarily reflected elsewhere in the world. In Europe in particular, mechanical ventilation systems for smoke control within rail tunnels have taken a much less central role within the standards framework."

Jan 1, 2016

By Nathan Bowersox, Zuzana Skovajsova, David M. Jurich, Brian Harris

When unwatered after more than 50 years of operation, the White Rock Tunnel of the Upper American River Project in the foothills of the Sierra Mountains exhibited failing rockbolts and ground falls. Repairs designed for the 5 mile-long, 24-foot horseshoe unlined hydropower tunnel included pattern rock bolts, shotcrete, and cleanout of the rock trap. The work, originally scheduled for two 3-month winter outages, was completed under challenging conditions in a single 4-month outage following a carefully sequenced work plan using robotic shotcrete and rockbolter machines. Flexibility, creative solutions, and collaboration by all parties were key to project success.

Jun 13, 2021

By Jerry Williams

GEORGE WEINMAN: At this time, our co-chair, Jamie Davis from Phelps Dodge, will come to the podium. JAMIE DAVIS: Our next speaker is Jerry Williams from Phelps Dodge, Morenci. Jerry is the maintenance planning supervisor and is in charge of preventative maintenance and maintenance scheduling. Jerry's group uses predictive tools to monitor and predict the equipment failure throughout the mine, from pumps to shovels to motors, you name it. The title of Jerry's talk is "If You're Not Using Predictive Tools, You're Behind the Curve." I’ll turn it over to Jerry.

Jan 1, 1998

By William H. Langer

I spent 41 years as a geologist with the US Geological Survey (USGS) conducting geologic studies and preparing peer reviewed maps and reports describing the results of those studies. Since retiring from the USGS in 2011, I have been a consultant specializing in aggregates and other industrial minerals. Consequently, I have had the opportunity and pleasure to apply the information contained in those kinds of geologic maps and reports to real-life situations. About half of my consulting is performing due diligence for mineral resource evaluations of one type or another where resource information has been provided by the property owner. Many of those jobs necessitate that I conduct desktop studies followed by field work. I then use my information to review and comment on the written reports of others; reports variably referred to as geologic reports, resource studies, reserve analyses, and so forth. While there are many well written reports addressing geologic resource issues, I was surprised to see that there are also a significant number of so-called geologic reports that only pay cursory attention to geology. Unfortunately, that lack of rigorous geologic investigation commonly leads to erroneous conclusions. This paper addresses three such reports covering concrete sand, metallurgical gravel, and proppants (frac sand). Although all three examples are located in the Gulf Coastal Plain Province, I do not reveal the exact location of any of the properties for purposes of confidentiality. Furthermore, I have generalized the site descriptions and illustrations. However, all the descriptions faithfully define the geologic situation.

Feb 1, 2024

By Silas Li, Michael Harris-Gifford, Jason Choi, William H. Hansmire

Twin-bore tunnels with a single track in each tunnel are currently the most common subway tunnel configuration. However, a large diameter single-bore tunnel with two tracks separated by a center wall could replace twin-bore tunnels and introduce potential benefits but require necessary modifications to the subway system. In particular, a nominal 40-foot-diameter single-bore tunnel can be considered in lieu of nominal 20-foot-diameter twin-bore tunnels. This paper discusses the benefits and modifications introduced by replacing twin-bore tunnels with a single-bore tunnel, with respect to various elements of the subway related to the tunnel, stations, track, and tunnel systems.

Dec 1, 2022

By Nicholas Tabor, Norbert Fuegenschuh, Richard Taylor, Jean-Marc Wehrli

The Plymouth Tunnel forms part of the 16-mile long route of the Purple Line Light Rail Project promoted by the Maryland Transit Administration. The tunnel is approximately 1,220 feet in length with a shallow vertical alignment located beneath a residential area. Challenging mixed ground conditions included surficial soils, decomposed Saprolite, and highly weathered to fresh rock requiring the use of the Sequential Excavation Method (SEM) for construction. This paper discusses innovative approaches implemented during construction as well as challenges faced during planning and installation of a spray-applied permanent concrete liner.

Jun 13, 2021

By Frederick McNeill, Mahmood Khwaja, Benjamin Lundsted, David Polcari, Michael S. Schultz, Timothy Clougherty

The City of Manchester, New Hampshire, is embarking on one of its largest public works projects in history to construct a 12,000 foot long, large-diameter, conveyance tunnel through downtown Manchester. This area has challenging geology with undulating bedrock (granite, schist, and gneiss) profile overlain by fluvial deposits. Understanding the subsurface conditions is key to mitigating project risks, establishing plan and profile for the tunnel, and selecting the most cost-sensitive and technically appropriate tunneling method. This paper presents the project team’s approach for conducting the ground investigation, developing preliminary subsurface profile, and the considerations for selecting the tunneling method.

Jun 13, 2023