Effect of soil stiffness on bearing characteristics of large-diameter and super-long steel pipe pile based on FLAC3D

In recent years, more and more large-diameter and super-long steel pipe piles are widely used in bridge and port engineering. But so far, people know very little about their bearing characteristics and there is no suitable calculation method of their bearing capacity in the design specifications. En engineering design, computational theory of ordinary piles is referenced. We all know that carrying capacity of large-diameter and super-long steel pipe piles is very closely related to the surrounding soil stiffness, but we do not know how they influence each other. In the paper, the effect of soil stiffness on vertical bearing and settlement features are studied for large-diameter and super-long steel pipe pile based on the three-dimensional continuum medium fast lagrangian method (FLAC3D). The result shows that the settlement of pile top will be reduced and side friction resistance of large-diameter and super-long steel pipe pile can be increased effectively if the stiffness of soil around the piles become stronger under the unchanged load. But when the stiffness of soil exceeds a certain intensity, the rate of pile top settlement reducing decreases gradually. In other words, when the soil stiffness increases to a certain extent, continue to increase the stiffness of soil around piles can not effectively reduce the settlement of pile top. It is obvious that the stiffness of soil around pile has a direct impact on the pile settlement characteristics and bearing characteristics. The conclusion is of significance for the reasonable design of large-diameter and super-long steel pipe pile foundation in engineering applications.