Bertha's scheduled maintenance stop
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Bertha Demo Period Done, Resumes Mining

The Bertha tunnel boring machine has resumed chewing away beneath Seattle after a ‘suspension for cause’ order from WSDOT shut it down in January following two safety incidents. The BTM began tunneling with some conditions […]


Malcolm Drilling's clamshell bucket taking a scoop out while excavating the access pit
Project Related

Update on Access Pit for Repairing Bertha TBM

There hasn’t been much to report recently for the Alaskan Way Viaduct Tunnel Project in Seattle. As you probably know, Bertha has not advanced since about December of 2013 after drilling through an abandoned steel […]


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Articles

Bertha – The World’s Largest Tunnel Boring Machine

clip_image002Perhaps you’ve heard of Bertha, the World’s Largest Tunnel Boring Machine or TBM? She’s currently working her way underneath Downtown Seattle, excavating the Alaska Way Bored Tunnel to replace the aging Alaska Way Viaduct. This $2 Billion megaproject is an incredible feat of engineering on so many levels. I was in Seattle in September for the Association of Engineering Geologists annual meeting, and was fortunate enough to attend a field trip to see the launch pit and Bertha before she began her tunnel drive. It was an unforgettable experience for this engineer! In this article I give an overview of the project and Bertha herself, discuss some of the geotechnical features, and share my photos and video. Check it out!

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Roadheader
Available Resources

Roadheaders in North America

Drill and Blast and Tunnel Boring Machine are two common types of tunnel construction methods. But roadheaders have been around for many years, getting their start in the coal mining industry. So where do they […]


Robbins TBM or Tunnel Boring Machine being used in Zhengzhou, China for Line 1 of their Metro.
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Robbins EPBs Undercut Downtown Zhengzhou

The City of Zhengzhou is set to become a major rail crossroads for China, located at the intersections of China’s major North-South and East-West lines. Currently tunneling with tunnel boring machine (TBM) is taking place […]