This presentation explores the current trends in tunneling procurement and delivery being used across the Americas. This includes a comparison between conventional and alternative delivery methods as they have been applied to tunnel projects in transportation and water/wastewater. The paper will illustrate methods such as design-build, progressive/modified design build, construction management at risk and public-private partnerships and how alternative delivery methods have been successfully used and challenges faced as they are applied to a wide range of tunnel projects across the USA.
A formal risk management process is widely implemented in our industry and this process is acknowledged as being a benefit to projects. However, risk management has descended to the level of a box-checking exercise for some projects. This session will present a framework of the basic needs and tools for project risk management. it will go on to provide tips for re-energizing and engaging the project team to get the maximum benefits from these processes, both for the project and for all project participants.
Dr. Brierley will discuss a nine-step process that is required in order to produce good designs and good contract documents for tunneling projects. In general, tunneling projects are radically different as compared to all other types of civil engineering projects because 100% of a tunnel comes into contact with the ground and because 75% of the risks associated with a tunneling project are related to construction procedures rather than the finished facility. As a result of the above, an enormous amount of thought must be given both to how the ground is “described” and to how the ground will “react” to proposed construction procedures, and, finally, to how the ground is “indicated” in the contract document via the Geotechnical Data and Baseline Reports. It is also important to note that the contract document must paint a “consistent” picture of construction procedures among the geotechnical documents and the plans and specifications.
Factors that make tunneling difficult are generally related to instability, which inhibits timely placement or maintenance of adequate support at or behind the tunnel face; heavy loading from the ground which creates problems of design as well as installation of a suitable support system; natural and man-made obstacles or constraints; and physical conditions which make the work place untenable unless they can be modified. In many cases special approaches or arrangements must be made to safely and efficiently excavate and stabilize the tunnel as it passes through this “Difficult Ground”. In this lecture, emphasis will be placed on creating and maintaining stable tunnel excavation in ground in TBM and SEM construction. Examples projects such as Chinatown Station in San Francisco, Istanbul Strait Crossing, and Alaskan Way tunnel will be used to illustrate the challenges.
After a brief introduction of what Construction Management is, and the forms it takes, Roger will discuss the role of Construction Managers on tunneling contracts. He will give a number of examples of how CMs can add value , provide expertise to the Owner and minimize contractual disputes at all stages of a project, while encouraging innovation and actively managing risk.
NATM Design and Construction” introduces the tunnel design principles for the application of the Sequential Excavation Method (SEM). The presentation addresses the main aspects of SEM tunneling including: Ground Classification, Definition of SEM Excavation and Support Classes, Ground Support Elements, Structural Design, Instrumentation and Monitoring, Contractual Aspects, and Risk Management. Selected case histories are provided to demonstrate the range of applications ranging from shallow soft ground tunneling in urban settings to tunneling in rock.
This presentation gives the practical aspects of designing and construction and underground lake tap. Multiple examples will be presented.
Overview of tunnel lining design principles. Review empirical, analytical and numerical modeling techniques for load determination. Describe design considerations including excavation methodology, groundwater conditions, and settlement criteria in terms of impacts to overlying structures (streets and utilities). Present initial support and final lining systems as well as pre-support techniques for soft ground and hard rock tunnels. Some case studies will be shared.
Design evolution of the segmental liner for SR 99 Tunnel in Seattle, USA, one of the world’s largest bored tunnels. The 57.5-foot diameter, 9,300-foot-long-tunnel under Seattle reached depths of 215 feet in an active seismic region. The presentation focuses on the evolution of the SR 99 tunnel single-pass liner from conceptual through final designs, and describes several influencing factors on lining design including alignment, traffic flow, fire life safety, seismic safety, constructability, and the impact of interior structures as well as other geo-structural challenges.
A unique perspective of state-of-the-art practices for design, construction, operation, and maintenance of deep tunnels for water, wastewater, combined sewer conveyance and with a goal to achieve the most efficient, resilient, and future-ready systems. This presentation touches upon innovations in the planning, hydraulic modeling, deep tunnels and lining systems, large reservoirs, diversion and drop structures, operational and maintenance strategies and associated hydraulic and mechanical control systems such as pump stations, gates, valves and instrumentation and monitoring components with examples of systems both in design and operations.
This presentation will introduce the state-of-the-art practices in today’s tunnel instrumentation and settlement monitoring, covering both classical geotechnical instruments as well as newer technologies such as AMTS and satellite radar interferometry through case studies. New advancements in sensor design, wireless communication and data presentation will also be discussed.
Whether for utilities or traffic, tunnels require communication solutions. These solutions can be implemented during the tunnel construction stage and during the operational stage.
Leaky Feeder, Wi-Fi, LTE, Wireless Portable Solutions or Mine phones are the most common communication systems for tunnel projects. Understanding the pros and cons thereof is essential to know which one is more convenient for your tunnel project. Solutions for tunnels classified as Class 1, Division 1 and Class 1, Division 2 will also be discussed.
The most common owners’ requirements regarding tunnel communications will be given. Being familiar with modern technologies will help contractors to include accurate quotes in their biddings and to meet all the project requirements.
Communication systems may include personnel and vehicle tracking, tunnel access control, environmental monitoring, emergency alert systems, access to the internet, smartphones, TBM data, etc.
Recommendations for underground voice communication systems and data networks will be provided.
The presentation will introduce and explain the Deep Soil Mixing technique. Case histories will be used to illustrate potential applications, overcome challenges, and mitigate risks on tunnel projects.
The SR99 bored tunnel will replace the double-deck Alaskan Way Viaduct in Seattle, WA. Bertha, at 57.3-ft in diameter, was the world’s largest EPB-TBM at time of launch in 2013. An access shaft was installed in front of the TBM to recover the cutter head. Access shaft design and construction overcame difficulties including buried structures, archaeological concerns, limited site access, complex geology, adverse groundwater conditions, and proximity to the adjacent viaduct that remained in service. The project required installation of deep secant piles up to 10-ft diameter, multi-stage dewatering, structural and hydraulic grouting, structural and geotechnical modeling, and real-time instrumentation.
John will be presenting an overview of the recently completed $260 million planning process for the nearly 80 miles of large-diameter tunnels that will be constructed for the California WaterFix. The presentation will include detailed information on the current plans to begin design and initial construction of all the WaterFix facilities, including the river intakes, tunnels and pumping plants. I will discuss the organization of the implementing organization that has been formed to manage the implementation of this $17 billion program.
The Ohio Canal Interceptor Tunnel is a combined sewer overflow project being performed by the joint venture of Kenny/Obayashi V for the city of Akron, Ohio. The tunnel is being bored using a 9.2 Meter diameter Robbins Crossover EPB TBM designed to mine through three distinct geological zones. The focus will be on the TBM design for mixed ground geology, the logistics of the TBM delivery and assembly, and discuss some of the challenges encountered while mining through varying ground conditions.
Through the Regional Connector case history (as well as a couple of other projects examples), the speaker will discuss some planning aspects, production enhancements and challenges of tunneling projects. Real case examples will highlight how safety, logistics, schedule, cost and risk can lead to engineering of unconventional construction methodologies and sequences of work.
The 21.6ft diameter Single Shield Hard Rock TBM for Delaware Aqueduct Bypass Tunnel Project was assembled in a 900ft deep, 30ft diameter shaft. The total weight of the TBM and trailing gear is approximately 1,000tons with the heaviest TBM component lowered down the shaft exceeding 100tons. A custom designed shaft hoist was built to accommodate the TBM assembly and the tunnel excavation and the presentation will cover details about the hoist, the preparations made for the TBM assembly and launch of the TBM, as well as reporting on tunneling progress to date.