Abstract: New bored grouting PHC nodular pile is a new kind of composite pile. And it has a lot of advantages, such as higher bearing capacity, more technologies, and higher security. For the sake of getting to know the compressive mechanical characters of new bored grouting PHC nodular pile, ABAQUS is used to simulate the vertical compressive load test. Comparing the simulated result with the field test result, the reliability of ABAQUS numerical model is acceptable. And it is found that: the radius of nodular stress influence is 2-3 times pile diameter; there is no friction at about 1.6-1.8 times pile diameter distance around of the nodule; ultimate bearing capacity of the nodules increases linearly from top to bottom except the first and the last ones. It is also shown that nodular space, sickness of soil-cement and the elastic moduli of soils of pile side and pile tip influence ultimate bearing capacity of the composite pile; and the elastic modulus of soil-cement can be ignored. Existing formulas of ultimate bearing capacity can’t work for mechanical characters of the new composite pile well. So, by combining theoretical analysis and compressive mechanism, a new formula of ultimate bearing capacity considering nodular influence coefficient is proposed; and its validity is verified by field tests.

Key words: new bored grouting PHC nodular pile, ABAQUS simulation, simplified model, ultimate bearing capacity, nodular influence coefficient, nodular space