摘要
The paper summarized the research actuality and application fields both in China and abroad. The design structure,specification and key techniques of QHZ- 2000 casing rotator are elaborated. The paper analyzes the structure principle and the application characteristics of casing string,hammer grab and drilling tools for underground obstacles removal;and also summarizes the construction process,mechanism and applicable scope of full casing cast-in-place pile,underground obstacles removal and pile extraction in full casing. This study fills the gap of independent research and development of casing rotator in China; it is environmental,universal and safe piling equipment and a new foundation drilling method with no mud used in urban construction and foundation works.