Cumberland Gap Tunnel Pavement Problem--Kentucky Highway Investigative Task No. 50

In efforts to gain a better understanding of where the voids beneath the pavement in the Cumberland Gap Tunnel originate, the Kentucky Transportation Center proposes that additional ground penetrating radar (GPR) work be preformed on the wall structure in both tunnels in the following areas: stations 119+50 to 124+50; 126+00 to 130+00; 137+00 to 140+50. The GPR field collection process will include collecting data with both a 900 and 400 MHz. ground coupled antenna. Although it is uncertain at this time, it is presumed that one antenna will perform better than the other for this application. Scanning the wall structure will be preformed approximately seven to nine feet above the road structure using KTC's vehicle (figure I). This survey will involve scanning in a horizontal direction from beginning to ending station numbers as noted above. If so desired, scanning can be performed on the ceiling in the same manner. However, equipment to access the ceiling will need to be provided on-site by others. Once the GPR data has been collected, it will be reduced and placed in graphic format. In the event that the GPR data is unable to be interpreted, therefore making data reduction unnecessary, the Cumberland Gap Tunnel Authority will be relieved from the data reduction fees quoted in this proposal. This proposal also includes services previously performed by the Kentucky Transportation Center but not covered under any previous contracts.