Study On Construction And Bearing Behaviors Of Ram-compaction Pre-stressed Pipe Piles With Composite Bearing Base

The ram-compaction pre-stressed pipe pile with composite bearing base as a new carrier pile, has been applied in engineering in recent years. It is the use of pre-stressed concrete pipe pile for the body, with technical features of the pipe pile and the carrier pile, and it is easy to ensure the quality of pile, improve the capacity and reduce the settlement. It can support the dense soil in the depth through the thick soft soil in the shallow, and the length of pile can reach more than 20m. It broadens the scope of applications of common carrier piles.Currently, such piles in the engineering application are still relatively less and lack relevant skills and experience of design and construction, and also lack systematic study of bearing behavior. Firstly, the article describes the force mechanism of the ram-compaction pre-stressed pipe pile with composite bearing base, especially the spherical expansion of cavity of expanded head; and then introduces design theory methods and theory of composite pile foundation from the vertical bearing capacity and settlement. The article proposes a number of construction problems that may arise with a actual project in Tianjin, such as quality control of the pile, soil-squeezing effect, and reducing and isolating vibration technology, etc. It also gives the appropriate solution for construction of a reference.Finally, the article adopts ABAQUS software for the finite element analysis of such piles, with the ram-compaction pre-stressed pipe pile with composite bearing base and common PHC pipe pile compared, and concludes much corresponding law of working properties. It can better explain working properties of the pile and guide the construction and design of pile.