Being in close proximity to Washington, D.C., Connelly and Associates Inc. often has the opportunity to work on the grounds of national monuments and other historic places. These sites present a significant challenge for drill crews, as they must maintain the drill site in immaculate condition during and after the project. In late October and early November of 2006, Connelly, one of the largest geotechnical drilling firms in the Washington, D.C., and Baltimore areas, was hired by Schnabel Engineering Inc. to install geotechnical instrumentation and monitoring wells in test boreholes at the Jefferson Memorial in Washington, D.C. The purpose of the investigation was to determine soil and ground water conditions related to upheaval and movement of the surficial sidewalks, pavement and seawall along the Tidal Basin.

Connelly supplied a truck-mounted CME 55 and a CME 550 all-terrain drilling rig to perform the drilling operation, utilizing hollow stem augers to advance the borings to bedrock. Diamond core drilling by NQ wireline techniques procured rock core samples, and provided a stable socket for the inclinometer pipes installed along the seawall. All auger cuttings were captured at the surface by specially designed catchment tubs and then transported by skid loader to a roll-off dumpster. Heavy-mil plastic covered the areas under and around the drilling machines to prevent unwanted spillage into the Tidal Basin. Two borings also were drilled under the memorial building, using a motorized cathead and tripod to obtain samples and install a well.

 

Site control was necessary throughout the project since the memorial remained open for visitors. The firm’s previous experience at other national places of interest, including the U.S. Capitol building and the White House, helped ensure successful completion of this project without incident and within project deadlines.