Abstract: This paper presents a case history of the highway bridge project in Enshi, Hubei Province. The bridge foundation type selected the percussive bored and cast-in-place concrete piles based on the characteristics of the rugged and complicated geological conditions in mountainous areas. Due to the complexity of the geological conditions at the project site, different percussive installation methods with small, medium and large strokes drilling should be utilized in the construction in accordance with various subsurface conditions. At the same time, the drilling waste should be discharged immediately to maintain the required density and viscosity of the drilling slurry. The bored pile shaft quality inspection was also performed by the ultrasonic method on the shafts that meeting the curing age. The test results show that: the integrities of bored pile shaft structures were sound with a Class I grade. The results also suggested that the application of the percussive installation method can effectively ensure the quality of the bored pile foundation for highway bridges in the mountain area. 

Key words: bridge engineering, percussive bored and cast-in-place concrete piles, installation methods