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By Verya Nasri, Jaeseoung Lee, Ashish Bhargava, Shashank Gupta

This paper presents the unique design and construction challenges for the Technoparc Station, located in downtown Montreal as a part of Réseau Express Métropolitain (REM), a light rail rapid transit system. The station is located 15 m below the street with rock-bearing secant pile wall as the primary structural system working as both the retaining and gravity structure. The paper highlights the challenges related to the support of excavation structure, invert slab resisting high hydrostatic forces, waterproofing tightness etc. It also focuses on the importance of Building Information Modeling (BIM) in underground tunneling projects for effective coordination, clash-free, optimized design and costs.

Jun 13, 2021

By Brian Young, Ben Pantony

Interferometric Synthetic Aperture Radar (InSAR) has played an integral role in many large scale tunneling projects globally. Until recently, it has been regarded as a complementary monitoring tool. On the Los Angeles Metro Purple Line Phase 1, InSAR was proposed as a primary means to replace weekly and bi-weekly surface monitoring requirements on surrounding critical infrastructure. This paper will summarize the statistical analysis approach engaged in order to compare and contrast a year of historical InSAR data to known geodetic survey data, in order to utilize InSAR as an operational monitoring tool on this project.

Jun 13, 2021

By Timothy O’Rourke, Karrie Buxton, Chris Lynagh, Daniel Dobbels, Frederick Vincent

The Doan Valley Storage Tunnel Project in Cleveland Ohio was constructed to control Combined Sewer Overflows (CSOs). It is a complex system of three tunnels ranging from 8.5 to 18 feet in diameter with a total length of about 2.3 miles that was put into operation in mid-2021. The project lies within and below the cultural, educational, and medical hub of Cleveland, which presented unique design and construction challenges. This paper provides a case history of the design and construction, with particular attention given to lessons learned in devising a large tunnel system that can carry both dry and wet weather flows constructed in rock with limited cover, within a flood plain area and vibrant urban center

Dec 1, 2022

By John Murray, Daniel Ebin, Robert Gould, Yiming Sun, Lizan Gilbert

The Atlanta Plane Train Tunnel West Extension is being constructed at Hartsfield-Jackson Atlanta International Airport using the Sequential Excavation Method (SEM). The tunnel has shallow ground cover and mixed-face conditions and passes underneath the SkyTrain and MARTA stations and airport terminal buildings. It includes a twin tube Bifurcation with a span of over 45 feet and ground cover of 12 feet. A flat roof is being constructed at the Bifurcation to maximize rock cover and minimize surface settlements. This paper focuses on design and construction challenges for the Bifurcation and tunneling beneath the world’s busiest airport, while minimizing impacts to operations.

Dec 1, 2022

By Pafos Busch, Martin Fischer, Johannes Jaeger

The Spitzenberg Tunnel is a 600 m (1,970 ft) long twin tube motorway tunnel on Germany’s Autobahn A44 between Kassel and Eisenach. Since flexibility was considered to be very important in the continuously changing geological conditions, NATM was chosen as the construction method. When passing an old quarry with only 1,80 m (6 ft) of overburden, the excavation works became extraordinarily challenging. This paper not only describes the special methods, like double sidewall drifts and pipe umbrellas applied in this zone but also highlights the cooperation between the parties involved, which in combination made the project a joint success.

Jun 13, 2021

By David Maust, Rob Albinger, Mike Walling, Michael Rispin

The safeguarding of health and life is the number one priority for underground infrastructure projects. While culture and approach are critically important, the industry has also seen the development of innovative tools and technologies that assist in making the underground environment and working places more safe and secure, both on an everyday basis and in the event of an unexpected occurrence.

Dec 1, 2022

By Samer Sadek, Phoebe Cheng, Changmo Kwon, Myat Ohn

BART Facilities Standards (BFS) Structural Criteria is a living document that governs planning, design, and construction of all BART projects. Since its development, the document undergoes incremental changes and updates to reflect policy changes, changes in local, State, or national design codes and guidelines, advancements in engineering and technology, or based on the performance of past built infrastructure. In 2020, the BFS-Structural Criteria underwent a comprehensive update and was released with BFS version 3.2. This paper summarizes the updates to the Tunnels and Underground Structures Section of the Structural Criteria, and provides insights to the basis and logic of the requirements.

Dec 1, 2022

By Chris D. Breeds

Northwest Boring, Inc. (NWB) deployed a skinned up AVN 2000AB Microtunnel Boring Machine (MTBM) to install 7.5-foot long, 118-inch outer diameter reinforced concrete pipe (RCP) sections along an alignment between the Fremont (FRS) jacking shaft and the 3rd Avenue (3RS) receiving shaft for the Ship Canal Water Quality SCWQ Project. The alignment includes: a 67-foot long straight section, a 367-foot long curved section excavated along a 650-foot radius curve, followed by a 182-foot long straight section. This paper describes the project including planning and design, manufacturing, equipment installation in the 90-foot-deep FRS jacking shaft, egress through the secants and microtunnel operations required to complete the shaft and install the required casing pipes.

Dec 1, 2022

By Ross Goodman, Jesse Salai

The Ohio River Tunnel Project encountered multiple unexpected geotechnical challenges such as crown and invert instability due to the overstress condition affecting the strata above, below, and in the tunnel alignment during and after TBM excavation along with the potential for methane inflow. This paper showcases how the orientation of a tunnel alignment has a significant impact on how in-situ geological stress can impact the excavation of a tunnel from the contractor’s point of view and how geological features influence gas inflow to the alignment over time.

Jun 13, 2021

By Nathaniel White, Todd Kilduff, Justin Laviolette, Dan Laviolette, Randy Zeigler, Sean Sundermann

The Mitchell Point tunnel is a part of several ongoing efforts to connect the 12-mile-long Historic Columbia River trail between Mitchell Point Outlook to Mitchell Point Drive. The tunnel lies inside the Mitchell Spur entablature basalt geologic feature, extending 647 linear feet utilizing a typical horseshoe section with a height of 14.5 feet. The Oregon Department of Transportation (ODOT) required proper vibration control to minimize potential impacts to Interstate 84 and Union Pacific rail immediately below the tunnel excavations and sensitive, rare plants. The method of designing the vibration monitoring program and the results of its implementation show the iterative process of using monitoring to improve blast design as excavation proceeds, such as reducing air overpressure and COVID-related supply chain-constraints.

Dec 1, 2022

By Devan Naik, Matthew Stokes, Andy Nigro

This paper describes the surgical removal of a 24 ft dia. Slurry Shield TBM entombed beneath one of the country’s busiest commuter rail interlockings, the Harold Interlocking in Queens, NY, and the construction of the interface to a cut/cover tunnel which extended the mined tunnel section. A sophisticated SOE was built around the TBM to support active track loads within 8ft. of the excavation. Once the TBM head and guts were removed, a full round CIP lining was installed connecting the existing precast tunnel liner to the C/C tunnel under construction. All this construction was done on a narrow island of land without road access nestled between 7 mainline LIRR/Amtrak rail lines.

Jun 13, 2021

By Taner Aydogmus

The A$29 billion Chevron-operated Wheatstone Project is one of Australia’s largest resource projects. Located at Ashburton North, 12 kilometers west of Onslow in Western Australia, the project will consist of two Liquefied Natural Gas (LNG) trains with a combined capacity of 8.9 million tons per annum and a domestic gas plant. The LNG Plant will serve the offshore gas fields, which are situated some 250 km off the coast of Onslow in Western Australia. Once operational and on-stream, the Wheatstone Project will contribute to Australia becoming the world’s second largest exporter of LNG. For crossing the environmentally sensitive shore area, a micro-tunnel with an internal diameter of 2 m and approx. 1,242 m in length has been constructed by means of the pipe-jacking method. The micro-tunnel will accommodate a 1.1 m diameter pipeline (trunkline) to deliver gas from the offshore fields LNG Plant. The Wheatstone shore crossing design involves a number of unique challenges owing to its coastal location, where the alignment crosses through a shore area and terminates in a marine environment. This paper provides an overview of the Wheatstone Shore Crossing Project, presents the key features, and discusses the main aspects of the micro-tunneling design.

Jun 13, 2021

By Yiming Sun, John Stolz, Jakob Walter, Drew Mason

The Courthouse Commons SEM Tunnel was excavated within 6 feet of cover beneath two buildings in downtown San Diego utilizing high-precision geotechnical instrumentation. The excavated dimensions are approximately 25 feet in diameter and 328 feet in length connecting two in-service detentionlevel security buildings. Presupport includes large-diameter grouted canopy pipes and smaller pipe spiles. Initial support consists of fiber-reinforced shotcrete with lattice girders. This paper presents observed ground and structure behavior and lessons learned. During construction an unanticipated brick structure was encountered, and methods were developed to improve adhesion of shotcrete to sandy soil and to reduce rebound

Dec 1, 2022

By Mike Wongkaew, Brandon Kluzniak, Per Vilhelmsson

Rail access to Ontario International Airport (ONT) has long been a goal of San Bernardino County Transportation Authority (SBCTA) to increase public transit options to ONT and provide incoming ONT passengers improved access to San Bernardino County and the greater Southern California region. This paper describes the planning for the Design-Build-Operate-Maintain (DBOM) delivery of an emerging technology tunnel connection between the Rancho Cucamonga Metrolink station and ONT. The paper discusses key technical considerations, challenges, and opportunities; conceptual configuration development; and construction planning and establishment of the footprint for the underground connection.

Dec 1, 2022

By Todd Kilduff, Paul Wilkinson

Microtunneling is rarely a straight forward “business as usual” endeavor. More often than not, these projects take twists and turns that require on the fly, out of the box solutions to get the project completed. This paper is a case history of a 63-inch diameter, Permalok, microtunneling project, extending nearly 700 linear feet under a hill forming the left-hand abutment to an earth embankment tailings dam. The job had three major and unexpected challenges that required unorthodox solutions. Challenge #1— Face Configuration: The Santiago Formation, a cemented sand formation with widely varying strengths, presented a challenge to configuring the face with regards to the number and length of pics and cutters. Subtle differences in type and size of the tooling had a big impact on the performance of the machine. Challenge #2—Eccentric Loading: Issues at the launch shaft with the Permalok pipe adaptors caused eccentric loading on the casing pipe. This issue resulted in overstressing and breaking of several pipe joints that ultimately led to seizure of the tunnel. Challenge #3—Back-tunnel Excavation and MTBM Recovery: There were many detailed considerations into excavating a recovery tunnel to retrieve the MTBM, especially being under a high hazard earth embankment dam.

Jun 13, 2021

By Greg Bold, Mahmood Khwaja, Yuannian (Jerry) Wan, Michael S. Schultz, William Simcoe

Beaver Creek Clean River Project will satisfy the consent decree requirements by capturing and treating combined sewage overflows. The project consists of, approximately, 2,700 feet of 30-inch trenchless pipe installation, a new screening/disinfecting facility, an expansion of an existing diversion structure, and a 72-inch internal diameter, 530-foot long mined tunnel. The tunnel portions are being progressed as early release packages. This paper presents the geotechnical exploration program and the subsurface conditions encountered; interpretation of the geotechnical conditions; and, approach to developing stand-alone packages for the tunnels to mitigate construction and schedule risks and continue to advance the project.

Jun 13, 2021

By Ray Brainard, Adriana Ventimiglia, Amanda Kerr

Preliminary design is underway for a new Southern Nevada Water Authority (SNWA) project that will ensure one of America’s most reliable water systems by providing continued, reliable water service to existing and future customers. The Horizon Lateral is a $1.6 billion water transmission pipeline that includes 7–10 miles of 108-inch finished diameter rock and soft-ground tunnels. The tunnels will traverse volcanic rock in or around the McCullough Mountain Range and the surrounding alluvial basin. The tunneling community will find relevance in hearing about this critical infrastructure project from a leading wholesale water utility owner with a proven track record for on-time, collaborative projects.

Dec 1, 2022

By Karin Bäppler

Lyon with half a million inhabitants is the third largest city in France. Urban agglomerations such as Greater Lyon demand intelligent underground solutions for the freedom of mobility of its inhabitants. The city and metropolitan area of Lyon provide an example of a city strategy adapted to the changing needs due to demographic and living standard trends. The Lyon Metro Line B with a length of 2.4 km is one of the strategic projects with regard to city planning and future mobility. The paper will highlight on this special area of application in singular diverse geology with sophisticated mechanized tunnelling technology.

Jun 13, 2021

By P. Schmäh

Nowadays, small diameter tunnels are increasingly considered in pipeline projects as an alternative for sensitive crossings or when soil conditions limit the use of conventional pipeline installation methods like HDD. Safety concerns play a key role, especially for inner-city installations. Pipe jacked microtunnels and small segment lining tunnels can serve as casing tunnels if access is required during construction for the change of cutting tools in challenging ground conditions or for maintenance of the pipeline in operation. Small diameter tunneling solutions offer a high degree of flexibility for alignment design in terms of geology, length and radius.

Jun 13, 2021

By Gunjan R. Bhattarai, Kumar Bhattarai

Recently, there has been an enormous increase of interest in artificial intelligence (AI), machine learning (ML), and their applications by researchers, government agencies, and the underground construction industry. Ultimately, these tools have the potential to automate the design and construction processes and boost productivity, safety, quality, and operational stability. This paper presents ongoing research and applications of artificial neural networks (ANNs), robotics, and 3D technologies in ground characterization, tunnel ground support prediction, risk projection and reduction, and productivity enhancement in TBM operations. The paper further investigates potential uses of AI, robotics, and 3D technologies in the underground construction industry

Dec 1, 2022