【摘要】：Despite significant advancements in in situ test techniques, construction practices, understanding of rock joint and rock mass behaviours, and numerical analysis methods, the design of bored concrete cast-insitu piles in rock is still largely based on the assessment of bearing capacity. However, for many of the rock conditions encountered, the bearing capacity of piles is a nebulous concept and a figment of the designer's imagination. Even if it can be reasonably quantified, it has little, if any, significance to the performance of a pile in rock. The load carrying capacity of even low strength rock(in most situations) is far in excess of the strength of the structure(for example, a building column) transmitting the load.Unsatisfactory performance of a pile in rock is usually a displacement issue and is a function of rock mass stiffness rather than rock mass strength. In addition, poor pile performance is much more likely to result from poor construction practices than excessive displacement of the rock mass. Exceptions occur for footings that are undermined, or where unfavourable structure in the rock allows movement towards a free surface to occur. Standards, codes of practices, reference books and other sources of design information should focus foundation design in rock on displacement rather than strength performance.Ground investigations should measure rock mass stiffness and defect properties, as well as intact rock strength. This paper summarises the fundamental concepts relating to performance of piles in rock and provides a basis for displacement focused design of piles in rock. It also presents comments relating to how piles are modelled in widely used commercial finite element software for soil-structure interaction analysis, within the context of the back-analysis of a pile load test, and proposes recommendations for pile analysis and design.