Abstract: Some of the construction sites in Hangzhou have limestone deposits, karst is generally developed. The embedment depth of the karstic bedrock is generally large, and it is difficult to completely characterize the degree of development rock cavities and their connectivity. In large construction projects, the karst site is a vital part of the pile foundation safe installations. However, the experience of pile installations in karst formations is relatively rare in Hangzhou area. As a result, it is important to summarize the lessons learned in the pile installations in karst. This paper presents a project case history. The subsurface geotechnical investigation and karst rock cavity treatment during the construction are also introduced.

Key words: Karst Rock Cavities and Pinnacles, CastinPlace Reinforced Concrete Piles, Construction Techniques