tunnels
Waterfront Tunnel Alexandria
Waterfront Tunnel – Alexandria Virginia The Herrenknecht TBM used by AlexRenew, Alexandria Virginia’s water treatment service. The TBM was named for Hazel Johnson, one of America’s leading pioneers for environmental justice. Hazel next to the launch shaft. After launching, Hazel proceeded to excavate the 2-mile long Waterfront Tunnel at an average depth of 100 feet.…
Read MoreNATJ Round Table
NATJ Tunnel Monitoring Round Table 2022 Click for PDF Monitoring and Instrumentation are experiencing wider usage and acceptance in tunneling,while also rapidly changing to integrate with the latest technology. In this year’s annual monitoring round table, NATJ spoke with experts Loic Galisson, VP USA and Canada for the Sixesense Grout; Angus Maxwell, Director and CEO…
Read MoreMicrotunneling at LAX
Microtunneling at LAX Project The LAMP project at LAX in California is a multi-billion dollar program for modernizing access to and from the airport. One part of the project involved installation of 9,700 feet of 48-inch diameter earthquake-resistant pipe within the City of LA street rights of way. Cut and cover was used for most…
Read MoreTunnels & Structures
Tunnel Construction & Surface Points GEO monitored an existing train tunnel as work proceeded on a new sewer tunnel. The AMTS in the photo was monitoring surface points, while another AMTS was monitoring within the tunnel. Other instrumentation included shape arrays, piezometers, extensometers, and automated vibration monitors.
Read MoreTunnelling & Settlement
Tunneling & Settlement Monitoring The Bellevue tunnel was aligned with a major thoroughfare. To monitor possible settlements, GEO-Instruments installed borehole extensometers above the tunnel centerline and arrays of road prisms across the road. Photo shows installation of a road prism. Borehole extensometers were terminated flush with the surface using a LidLink antenna. Measurements were transmitted…
Read MoreMetro Tunnel
DC Metro Tunnel GEO’s deployed an automated monitoring system in a WMATA tunnel. The system included strain gages, convergence gauges, tiltmeters, vibration monitors, and AMTS. The AMTS and prisms are clearly visible in the photo on the right. Also visible is one of the eight vibration monitors and wall-mounted geophones.
Read MoreTunnel & Piezometers
Piezometers along Tunnel Alignment Piezometers were installed in the roadway above the Bellevue tunnel alignment. The instruments were collocated with observation wells and inclinometers at 10 locations. All were automated with wireless dataloggers that were capable of transmitting data through the inspection plates. Piezometer readings were transmitted hourly and displayed on a dedicated project website.…
Read MoreM-Street Excavation
M-Street Excavation & Tunnel GEO monitored a 32-foot deep excavation and a WMATA metro tunnel adjacent to the excavation in Washington DC. The SOE consisted of drilled soldier piles braced with whalers and rakers. GEO’s technician can be seen on the wall. Monitoring prisms, a few visible in this photo, were mounted at the top…
Read MoreBellevue Tunnel Portal
Bellevue Tunnel Portal The East Link extension adds 14 miles and 10 stations to Sound Transit’s light rail system, carrying commuters between Bellevue and Seattle. This is a conceptual drawing of the south portal site, where the light rail enters the Bellevue Downtown Tunnel. This was the actual south portal site, cleared, graded, and ready…
Read MoreRosslyn Metro Station
Rosslyn Metro Station Project Overview Construction of twin residential and commercial towers adjacent to the Rosslyn metro station involved demolition of an entire block of existing buildings, blasting and excavation for deep foundations, and finally the construction of the towers. The station, ventilation shafts at each end of the station, a long escalator, and three…
Read More