Being in close proximity to Washington, D.C., Connelly and Associates Inc. often has the opportunity to work on the grounds of our national monuments and precious places. These sites present a significant challenge for the drilling 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 was hired by Schnabel Engineering Inc. to install geotechnical instrumentation and monitoring wells in test boreholes at the Jefferson Memorial. 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 installed three 100-foot inclinometers behind north seawall along the Tidal Basin, and inclinometers and vibrating wire piezometers were installed to measure movement in the wall. In addition, two tripod borings were completed to depths of 40 feet inside the Memorial to determine the soil profile.

A truck-mounted CME 55 and a CME 550 all-terrain drilling rig were employed 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 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. Connelly’s previous experience at other national places of interest, including the U.S. Capitol building, the White House and the Washington Monument, helped to ensure the successful completion of this project without incident and within project deadlines.

The skilled drill crews on this project: drillers Danny Bender and Wesley Wolfe, helpers Daniel Pao, Wes Smith, Travis Beachley and Marcelino Larios, and drilling supervisors Steve DeLosh and Tom Connelly. Owner Walter Connelly was on hand from start to finish of this high-profile project.