Monday, June 20
1:35pm – 2:00pm
Tunnel Options for the Mokelumne Aqueducts Resiliency Project
Speakers: Stephen Klein, Ken Johnson
The East Bay Municipal Utility District (EBMUD) supplies water to over 1.4 million residents of the East Bay through an aqueduct system extending from the Sierra Nevada Mountains to the San Francisco Bay Area. The water is delivered to the East Bay through the Mokelumne Aqueducts, which are comprised of three 82-mile long steel pipelines. Approximately, 10 miles of the aqueducts crossing the Sacramento-San Joaquin River Delta (Delta) consist of pile-supported elevated pipelines and this portion of the aqueducts is recognized to be vulnerable to seismic and flooding hazards. Previous studies evaluated alternatives for mitigating these hazards and increasing the reliability of the aqueducts for the next 100 years. The highest ranked alternatives involve construction of a 16.5-mile tunnel across the Delta and re-routing the existing aqueducts through this tunnel. This paper will discuss the tunnel options being considered for the Mokelumne Aqueducts in the Delta.
3:15pm – 3:40pm
Application of Large Diameter Single-Bore Tunnel for Subway Systems
Speakers: Jason Choi, Silas Li, Michael Harris-Gifford, William Hansmire
Twin-bore tunnels including a single track in each tunnel are currently the most common subway tunnel configuration. However, a large diameter single-bore tunnel including two tracks separated by a center wall could replace twin-bore tunnels and introduces potential benefits but necessary modifications to the subway system. In particular, a nominal 40 feet diameter single-bore tunnel can be considered in lieu of nominal 20 feet 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 subway system related to tunnel, station, tracks, and tunnel systems
Tuesday, June 21
10:40am – 11:05am
Updating the GBR Gold Book
Speakers: Amanda Elioff
Managing commercial risks associated with subsurface construction may be the greatest challenge the underground industry faces. The Geotechnical Baseline Report (GBR) was developed in the U.S. in an effort to stem increasing litigation in the industry. A GBR guideline document by the American Society of Civil Engineers was published in 1997 (Yellow Book) and updated in 2007 (Gold Book). This paper will overview the core objectives of a GBR, review its role within the Contract, and address key events and lessons learned over the last 15 years that have prompted a second update expected to be published in 2022.
Technology: Design Innovations - Salon G
Chair: Everett Litton
2:00pm – 2:25pm
Predicting Utilization Rate of Hard Rock Slurry TBMs by Discrete Event Simulation Model
Speakers: Anuradha Khetwal
The estimation of TBM utilization rate can be problematic due to the uncertainty involved in the tunneling system reaction to various geology along the tunnel. Moreover, the impact of operational and management issues on TBM performance is unsettled. This includes the occurrence and duration of downtimes and the uniqueness of projects relative to the geology, machine type, backup system, site setup, crew experience, and operational restrictions imposed on the project by localities. The CSM2020 is a model based on discrete event simulation that predicts machine utilization for single or double shield TBM. This model was developed by the Earth Mechanics Institute (EMI) team, using the database of tunneling activities which was compiled based on field observation and measurements in pertinent projects. In the current study, CSM2020 was modified to simulate the workflow of slurry TBMs. The operating principle of slurry shield TBMs is different than open-mode TBMs. The model was verified by comparing results with a recently completed project in the United States. As a result, the model offers reliable utilization rate estimation in different types of TBM by implementing appropriate workflow.
Wednesday, June 22
Technology: Digital Technology - Salon G
Chair: Tolga Togan
UCA Leaders - WSP is committed to the advancement of the tunneling industry. Come meet some of our UCA Leaders and get to know how they contribute!
Down for That Initiative – “Down For That” is an initiative that informs students about the underground industry through resources and opportunities to get involved. The website (undergroundcareers.org) is a one-stop resource for students, professors, and industry professionals to gain knowledge and share information on the underground construction tunneling industry.
Committee Members: Luis Avila, Everett Litton
UCA Working Groups
Working Group 2 – Research – The objective of this group is to investigate and assemble knowledge on emerging state-of-the-art or state of-the-practices in tunneling.
Committee Chair: William Hansmire
Committee Member: Luis Avila
Working Group 3 – Contract Practices in Underground Construction – The objective of this group is to develop contractual pronouncements addressing the most serious issues in underground construction and the appropriate responses contractually.
Committee Member: Everett Litton
Working Group 20 – Urban Problems – Underground Solutions – The objective of this group is to discover typical challenges of urban city environments and its planning and arrive at solutions by deploying sustainable approach to the underground space utilization.
Committee Member: Amanda Elioff
Civil Underground Curriculum Workshop & Outreach Program – This program aims to ‘teach the professors’ of junior level civil engineering students, specifically those who teach the introduction to structures, introduction to geotechnical engineering, and introduction to construction courses required of all Civil Engineering students. Specifically, we want these professors to weave underground concepts into those required courses. The goal of the program is to reach junior level civil engineering students who otherwise would not hear anything about underground engineering, and therefore would not consider pursuing a career in underground engineering.
Committee Member: Luis Avila
UCA Young Member Executive Committee – The UCA Young Members Executive Committee is a standing committee of the Underground Construction Association of the Society for Mining, Metallurgy, and Exploration (UCA of SME). The UCAYM Executive Committee strives to enhance the visibility of the Tunneling and Underground Construction industries with talented young minds throughout the United States. Additionally, the UCAYM Executive Committee is committed to providing resources to develop the professional careers of its members already within the industry.
Treasurer: Anuradha Khetwal
Past Chair: Luis Avila