Indoor Model Test Study And Analysis On Pile Bearing Characteristics Under Different Pile Toe's Conditions

So far, more and more scholars have been attracted by the phenomenon, that character of soil under the pile toe has influence on the development of pile shaft resistance within a certain scope near pile toe. However, there are very few research and test data about this. Based on the existing theory of pile bearing characteristics, by indoor model test of pile bearing characteristics under different pile toe's condintions, combining with the numerical method, single(group) pile's load transmission mechanism caused by the vertical load function, while there is same soil at pile side and different soil under pile toe (bearing stratum), is discussed in this article. Including:1. the relationship between load and settlement of sigle(group) pile;2. the axial force transmission characteristics of single (group) pile;3. the developing characteristics of pile shaft resistance, and the relationship between shaft resistance and tip resistance in the state of the ultimate bearing capacity;4. the change characteristics of earth pressure around group pile, along the depth;5. Regard the FEM software PLAXIS as tools, the single model under different toe's conditions is set up, and then the transmission mechanism of loads is analysed.Based on the model test result and the FEM result, the note under table 6.2.4-1 in Shanghai 《Code for design of building foundation》 (DGJ08-11-1999) has been considered to be reasonable. However, different views about the interpretation of its article have been raised, and the generation mechanism of enhancing effect of the soil under the pile toe responsed on the pile shaft resistance, has been discussed.Finally, the direction for further research is briefly discussed.