Test Research, Settlement Analysis And Stability Analysis Of Plain Concrete Pile Composite Foundation

Nowadays, Composite foundation is one of the most widely used soil improvement technologies. With higher and higher demand to soil improvement, composite foundation technology is developing continuously. Plain concrete pile composite foundation has been developed recently because of its high bearing capacity, little settlement, wide adaptation, good economical and social benefit. This dissertation has summarized the application, development and research of composite foundation and introduced the basic concept. At the same time, there are some analyses and discussions about the test research, finite element analysis and theory analysis.â‘ Test Research.By in-site test to plain concrete pile composite foundation, pile stress curve, soil stress curve and loading-settlement curve were got, then pile-soil stress ratio and load sharing ratio were also got. The test shows, when the bearing capacity of supporting course of piles' end is good, stress on the top of pile, soil stress between piles and the load sharing ratio will enhance with load's enhancing. The load-settlement curve deforms slowly and the total settlement is much smaller than the upper limit value which code has regulated. The test shows that Plain Concrete Pile Composite Foundation(PCPCF) has good characters of bearing capacity and settlement.â‘¡Finite Element Analysis.Using ANSYS6.1 finite element analysis software, the dissertation has made an comparative analysis to the bearing capacity and settlement of natural foundation, PCPCF and Composite Foundation of Rigid-flexible Composite Piles(CFRCP). The comparative analysis shows that, the two characters of PCPCF and CFRCP are different from those of natural foundation. The finite element analysis also shows both PCPCF and CFRCP can reinforce the natural foundation efficiently.â‘¢Theory Analysis.After analysising all kinds of settlement calculation method of PCPCF, the dissertation has come up with using composite deformation modulus to deduce the calculation formula of PCPCF. According to the results of finite element analysis, the dissertation has come up with practical calculating method of bearing capacity and settlement of CFRCP. After introducing failure model of PCPCF, the dissertation has deduced the circular arc method formula of PCPCF's total stability analysis. The analysis shows that PCPCF can improve the stability of natural foundation. At the same time, the dissertation has also perfected stability calculation method of composite foundation which has caverns.â‘£Examples Analysis.By two typical examples of PCPCF, the design method, construction method and loading test method were introduced and analysised in detail, which can be referenced to similar projects.