A network of flood control measures for two communities in the coal mining region of southeastern Kentucky has involved the construction of several hundred meters of high flood wall and the relocation of several bridges. A thick cover of weak alluvial soils at the sites made H-piles an economically viable means of foundation support for these structures. All piles were fitted with driving points and driven to refusal in sandstone, siltstone, and shale of Pennsylvanian Age. The refusal criteria used for all H-piles was five blows, with the selected hammer, per 6.35 millimeters of penetration. Altogether, 3,850 piles, which varied from 4.9 to 19.7 meters in length, were driven at the two major projects described in this paper. The first project is located at Pineville, Kentucky and the second project is at Harlan, Kentucky. Some of the geotechnical considerations and problems related to the pile foundations that were constructed at these sites are presented. Preconstruction foundation exploration data, design values, and assumptions are compared with the actual performance during construction. The sub-surface exploration consisted of standard penetration test, Shelby tube, and cone penetrometer borings through the overburden and wire-line coring in the rock. Laboratory test data for the rock is briefly discussed. The design axial load capacities, which were computed using 6 different dynamic design formula, are compared with the actual capacity measured by two field load tests on the Pineville project. The relative conservatism of these formula versus the measured capacity is examined. Particular focus is placed on the pile blow count data and actual refusal depths versus the top of rock elevation predicted from the foundation exploration. Variations in hammer energies, pile sections, driving points, and foundation conditions are described. A histogram of the penetration into rock for the first contract follows a Gausian curve. This was used to predict the distribution of penetration into rock for the second contract. The validity of this approach to predicting penetration into similar foundation conditions is discussed.
The 2,095 square kilometer Upper Cumberland River Basin in southeastern Kentucky has a long history of destructive flooding. The record flood in 1977 led to construction of projects to alleviate this problem. Two of these projects, the Pineville Floodwall and the Harlan Floodwall involved the used of H-piles driven to refusal in weathered shale as support for T-walls, closure structures, bridge abutments, pump stations, and gate wells. Both projects were built immediately adjacent to the Cumberland river channel and were tied in to high ground on either end. The Harlan project is located in Harlan County at approximately river kilometer 1,113. Construction was performed under one contract that began in August 1992 and was completed in January, 1996. In most geologic settings driving an end bearing pile into rock is reasonably straight forward. Provided, the pile tip is protected from damage, the refusal criteria is reasonable, and appropriate equipment, in good working order is used, a pile can be emplaced that will sustain its design load.
