CONSTRUCTION OF THE BIG WALNUT AUGMENTATION/RICKENBACKER INTERCEPTOR TUNNEL (BWARI, PART 1) -COLUMBUS, OHIO

摘要

The upper portion of the shaft was drilled to a diameter of 4.06 meters (5 feet 4 inches), leaving a gap of approximately 200 mm (8 inches) around the CMP casing, which was filled later with grout. After reaching the desired depth, the CMP casing was installed and grouted in place. As per the contract specifications, dewatering was not permitted in most of the sites. Thus, dry drilling was limited to few feet below the existing ground water table which in turn dictated the length of the upper casing. The top casing was also extended above ground surface to a level above the 100-year flood elevation to secure the shaft from potential flooding. This also acted as a protective ledge around the shaft for safety during construction.