Abstract: The case history of foundation construction methods for the long-span Feiyan tied arch bridge for Hejiang-Changjiang highway project is presented in this paper. The key aspects during the caisson installations are also evaluatedin the paper. The following results are found: 1) For the striking drilling method, the appropriate stroke should be determined based on the stiffness of various soils. The stroke setting for the soft or loose soils should be 1.0 to 2.0 meters; 2.0 to 3.0 meters for medium soils and 3.0 to 5.0 meters for the dense or hard soils. However, the maximum stroke should not be higher than 6.0 meters. 2) The low stroke and fast striking method should be used for alternating of soft and hard soil stratigraphy, hard stone pieces can be dumped into the borehole to form a firm platform in the hole. 3) for the quality acceptance, the circulated slurry pumped from the borehole should be uniform and without debris; No solid particles with dimension 2 to 3 mm by using the hand touch; the specific gravity of the slurry should be between 1.03 and 1.10; sand content in the slurry should be less than 2%; the viscosity should be between 17 and 20 s; the thickness accumulated at the bottom of borehole should be less than 80 mm. At the same time, borehole cleanness examination and cleaning should be performed immediately before the concreting work. 4) due to the special hydrological conditions at the bridge site, the disposal of the drilling fluid should be arranged with the variation of the hydrological conditions dynamically: When the groundwater level is deep and the groundwater recharge to the borehole is not high, single borehole pump disposal can be used, however, when the groundwater recharge to the borehole is large, and the groundwater water level is shallow, multiple borehole pump disposal method can be used. If the caisson length is not large, drainage ditches can be used around the caisson locations.

Key words: Hejiang Yangtze River Highway Bridge, Feiyan Tied Arch Bridge, Pile Foundation, Construction Technology