基于 P 波斜入射海相软土区螺旋桩动力响应分析

In earthquake-prone areas, more and more buildings are using helical piles as foundations, they have good aseismic ability. By establishing a 3-D finite element (FE) model and using viscoelastic artificial boundaries, seismic actions are equivalent to forces acting on boundary nodes. Here, considering effects of dynamic-static boundary conversion, the helical pile-soil body 3-D FE model with viscoelastic boundaries was established. Effects of different types of seismic waves, seismic intensity, incidence angle and number of spiral blades on axial force, bending moment and dynamic p-y curve of helical piles located underground in marine soft soil site were explored. The results showed that compared to bending moment, incident angle has a larger impact on axial force and dynamic p-y curve; seismic intensity has a larger impact on bending moment, while seismic wave frequency and number of spiral blades have a smaller impact on bending moment; under different PGAs of 0. 05^, 0. \0g and 0. 30g, the difference between the maximum and minimum bending moments of helical pile increases from 144. 1 Nm to 891 Nm with variation of incident angle; the study results can not only obtain interaction relation of underground helical pile-soil body in soft soil site, but also provide a basis for aseismic design of helical piles.