Application of the Grey Model in One-Dimensional Long-Term Creep Analysis of Coral Mud From the South China Sea

Abstract

Coral mud is widely distributed in the South China Sea. Studying deformation laws of coral mud is important to the infrastructure development in the South China Sea. In this article, a one-dimensional oedometer test of coral mud under near-natural conditions is performed. The exponential fitting model, Burgers model and ODGM model are used to analyse the time-strain relationship of coral mud under different vertical pressures. The self-fitting accuracy and prediction accuracy of the three models under different vertical pressures are compared. Then, the number of data points used in the model was reduced, and the associated change in accuracy and model stability of the three models were analysed. The study found that the ODGM model has high self-fitting, high prediction accuracy, and a high model stability when the number of data points is reduced, which describe the long-term nonlinear deformation of coral mud more accurately.

One-Dimensional Strain Research of Coral Mud Based on a Modified Burgers Model Considering Stress History

“…The water content, loading path, and duration of the three groups of tests are shown in Table 2. As the strain speed of the coral mud in a one-dimensional oedometer test generally decreased sharply 10 min after loading [16], the load duration of each load level for T1, T2, and T3 was 8 days, 1 day, and 10.5 min, respectively, to study the impact of different loading durations on the long-term nonlinear deformation of coral mud at 3200 kPa. In addition, T2 was also subjected to repeated unloading-reloading tests, to study the impact of stress history on the coral mud deformation.…”

“…Feng et al [15] produced the EVP model, considering unloading expansion in the long-term time-dependent behavior of Hong Kong marine deposits (HKMD), under the loading stage and unloading stage in a multistage loading oedometer test. In addition, with the development of computer technology, some scholars have also used the grey theory method to predict the long-term one-dimensional deformation of sediment, such as Weng et al [16]. Due to the complex deformation characteristics of sediment, it is difficult to make an analogy with the deformation of other well-known materials.…”