EA conducted a comprehensive seabed characterization effort in vicinity of the Thimble Shoal Tunnel element of the Chesapeake Bay Bridge Tunnel complex in the Lower Chesapeake Bay in support of Jacobs Engineering Group and the Chesapeake Bay Bridge Tunnel District. The work was performed over a 12-week period with the purpose of collecting deep cross-sections of the seabed as a means of characterizing the geotechnical and geochemical properties of the sediment column to be removed as part the construction of a new parallel tunnel along the 17‑mile Chesapeake Bay Bridge Tunnel connecting the Hampton Roads, Virginia area to the eastern shore of Virginia.
Six geotechnical borings to a depth of -255 ft below mean lower low water were obtained, as well as numerous shallower borings (-120 ft; mean lower low water) via sonic drilling in order to obtain samples of material that would be encountered during the construction of the Parallel Thimble Shoal Tunnel. The field program also required extensive coordination with the regional regulatory agencies (U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, and State of Virginia), maritime stakeholders, and channels users at the outset of the project to avoid impacts to commercial and military vessel traffic.
