Creep constitutive model of coral sand

Abstract

As the primary foundation material for island and reef structures, the long-term creep characteristics of coral sand can significantly impact the settlement and deformation of buildings. In this study, uniaxial creep experiments were conducted on coral sand from the South China Sea, and the creep characteristics of coral sand under different stress levels were analyzed. Five traditional component models were initially used to describe the creep behavior of coral sand, but significant errors were found when comparing the model's results to the experimental data. Therefore, the model was improved by introducing a time function and connecting an elastic body, a nonlinear H-M body, and a Kelvin body in series, to establish a nonlinear creep model that accurately describes the different creep stages of coral sand. Combined with a homotopy method to improve the inversion calculation, the required calculation parameters were obtained, and the accuracy of the model was verified through uniaxial and triaxial creep tests under different stress levels. The results showed that the experimental curve and the model results had a high degree of fit, with an average error of less than 1.5%, and can reflect the various stages of creep of coral sand well. Based on this, by comparing with field monitoring data, the combined average error of the two monitoring points is less than 5%. Therefore, this creep model has good engineering applicability.