(Leica Geosystems, Norcross, GA) -- Geo-Instruments has implemented one of the industry’s first automated laser scanning systems using Leica Geosystems technology for near-real-time geotechnical monitoring. The system is used to support construction of the Puget Sound Regional Transit Authority’s (Sound Transit) University Link (U-Link) light rail extension in Seattle.

The U-Link light rail extension will connect the three largest urban centers in Washington state. Beginning in 2011, the tunnel-boring machines will excavate a 3.5-mile, twin-bored tunnel from downtown Seattle to the University of Washington. Key to the project’s success is the ability to tunnel under Interstate 5, a major artery near downtown Seattle, without affecting the aging infrastructure, deep foundations, and existing utility lines.

Prior to excavation, Geo-Instruments installed a laser scanner-based fixed monitoring system to track fractional movements of the walls and highway surrounding the intersection during pit excavations and tunnel-boring machine passage.

 …