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Tunneling starts at Beacon Hill

Monday, July 11, 2005

TBM assembly at the West Portal near I-5 (Image courtesy of Sound Transit)

July 5, 2005 - Just arrived at the Port of Seattle, Sound Transit's new Mitsubishi tunnel boring machine (TBM) after transport from the factory located in Kobe, Japan.  The TBM will be used to construct the twenty foot diameter parallel running tunnels for Sound Transit's Link Light Rail through Seattle's Beacon Hill.  The tunnels will pass through the Beacon Hill Station complex located mid-way along the line as shown below.

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For additional information on this exciting project please visit Sound Transit's website.

While continued construction progresses over at the Beacon Hill Station site.  After completion of the slurry walls for the Main Shaft and the Ancillary Shaft, the Main Shaft was excavated to a depth of approximately 120 feet.

Installation of the necessary utilities, the breakout from the slurry wall was initiated by line drilling through the concrete. Subsequently, the concrete was chipped out and top heading excavation commenced for the first mined tunnel, (West longitudinal ventilation adit).

The top heading advanced three rounds, then the Main Shaft was excavated to the next level to facilitate bench and invert excavation.

So far the project is progressing well, shown below in an aerial view taken of the station project site looking NW towards downtown Seattle and Puget Sound.  More information on the challenging project will be posted as construction continues.

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Aerial View of the Beacon Hill Station site (Image courtesy of Sound Transit)

More information on the Seattle project will be posted as contruction expands underground.

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