Research on Vertical Bearing Behavior and Deformed Mechanism of Supper-long hole Bored Pile in Xi’an
|Keywords||Bored Static load test Bearing performance Deformation mechanism Load transfer function Statistical analysis Finite element numerical simulation|
With the rapid development of urban construction in Xi'an and ultra-high-rise buildings continue to emerge, long bored pile foundation treatment has increasingly shown its unique charm and prospects, but also on pile foundation design theory put forward higher requirements. Due to the complexity of the mechanism of interaction between pile and soil, the current study is not very perfect and theory lags behind practice. In this paper, a review under vertical loads single pile is calculated based on the theory, Xi'an four landmarks long pile static load test, analysis of loess foundation Bored load transfer law, the Q - s long pile curve showed a slow variant. Sliding Micrometer measured stress results analysis to calculate the variation characteristics of the super-long pile body compression deformation, axial force distribution characteristics the play pile side resistance and tip resistance characteristics and its influencing factors; single estimate Pile simplified method formula combined factor ξ verification and correction; pile side resistance of the lateral resistance of the soil at different depths level of play is not synchronized; loads to the top of the pile, the pile body with axial force pile depth increases, decreasing the ultimate load of the pile tip resistance proportion of not more than 15%, the proportion is very small, long piles in loess foundation for the performance characteristics of friction piles. Measured and calculated pile side resistance, tip resistance and pile-soil displacement obtained a long pile transfer function model, the transfer function of the pile side resistance hyperbolic, tip resistance transfer function for the bilinear hardening. On the basis of the above analysis, the study by the statistics of the of Xi'an 14 venues pile test data analysis, the pile side soil Soil Indicator: water content, the severe liquidity index, void ratio and compression factor and limit The correlation between the side of the resistance, and the use of liquid index and porosity than two physical indicators and the pile side resistance multiple regression to establish a pile side resistance quantitative analysis by the model, the correlation coefficient is higher. In addition, based on the stratigraphic architecture of the prototype pile given boundary constraints, finite element numerical model. By determining the appropriate parameters to simulate the transfer characteristics and pile-soil interaction between axial force, and were compared with the actual data.