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.
One wall of the excavation was located within 33 feet of a WMATA metro tunnel. The tunnel alignment is shown in blue.
GEO also monitored the WMATA tunnel near the site. Above, you can see the reflections from prisms mounted on the tracks, springlines, and crown of the tunnel.
This plan view shows a 350 foot span of the tunnel along with XYZ displacements calculated from measurements from each prism.