ZHU Wen-bo, DAI Guo-liang, WANG Bo-chen, et al. Study on cyclic characteristics and equivalent cyclic creep model
of the soft clay at the bottom of suction caisson foundation[J]. 2022, 43(2): 466-478.
DOI:
ZHU Wen-bo, DAI Guo-liang, WANG Bo-chen, et al. Study on cyclic characteristics and equivalent cyclic creep model
of the soft clay at the bottom of suction caisson foundation[J]. 2022, 43(2): 466-478.DOI: 10.16285/j.rsm.2021.1072.
Study on cyclic characteristics and equivalent cyclic creep model
of the soft clay at the bottom of suction caisson foundation
As the anchoring foundation of the tension leg platform (TLP)
suction caisson foundation is not only subjected to the vertical pullout load but also subjected to the cyclic load. However
there are few studies on the mechanism of the cyclic characteristics of soft clay under unloading condition. In this study
the cyclic triaxial tests under axial unloading were carried out to obtain the cyclic cumulative deformation and strain softening characteristics of soft clay. The results show that the degree of strain accumulation and softening coefficient were low under the condition of low static deviator stress and dynamic deviator stress. With the increase of dynamic deviator stress
the cumulative cyclic deformation gradually increased and rapidly developed in the early stage and tended to be stable in the late stage. Meanwhile
the softening of soil gradually increased. The cyclic cumulative deformation of soil increased with the increase of dynamic deviator stress
and the cyclic cumulative strain curve showed attenuation-stability creeping characteristics. Based on the tests
a formula for softening coefficient related to static deviator stress and dynamic deviator stress was introduced to describe the test results of soft clay under different stress levels. Considering the influence of static deviator stress
dynamic deviator stress and softening coefficient
an equivalent cyclic creep model of soft clay was established. On this basis
a three-dimensional equivalent cyclic creep model was built
and a finite element subroutine was developed. The finite element method for cyclic uplift capacity of caisson was established to analyze the cyclic cumulative deformation of soil. It was verified by comparing with the test results.