The Properties Of Self-expanded Diving Casing Cast-in-site Pile

With the rapid development of theory and technology of pile foundation,the application and technology of pile construction is becoming more and more diverse and complicated,the design of pile pattern and technology of pile construction gets rid of the stale and brings forth the fresh. Various new types of pile pattern have emerged in recent years. Self-expanded diving casing cast-in-site pile is one of them.In this paper,the recent development of single pile and self-expanded pile is introduced;the design of pile pattern and technology of self-expanded pile construction is summarized;base on field test results of self-expanded pile,the load transmission characteristic and load transfer mechanic of self-expanded pile are studied.Base on the finite element method,the major factors that affect the work behavior of self-expanded pile are studied,these major factors include the modulus of compressibility of pile side soil,bearing stratum soil and substratum soil;the ratio of length and radius of pile;the ratio of expanded body's radius and pile's radius;the depth into bearing stratum of pile end;load value and so on. The characteristic of stress and deformation of foundation soil bellow the pile end is analyzed. It is also compared with the common cast-in-site pile.Finally,two cases of plate loading test are analyzed. The theoretical calculations are compared with measured results. It is showed that the results by the finite element program are close to the measured results.