To consider the creep properties of rock and soil using finite-element simulation, current geotechnical finite-element software contains partial creep calculation modules. provided model parameters for numerical analyses of landslide deformation based on the results of slip-zone soil rheological tests.
used the Mohr–Coulomb and anisotropic models to simulate and explain the causes of slope change and creep behaviours. Furthermore, the meaning of model parameters used was not explained. However, the mechanical mechanism of creep was not considered. Other long-term deformation predictions for landslide bodies have been studied, in which predictions of landslides were based on mathematical models. Rutter and Green conducted creep monitoring on the Mam Tor landslide and established a nonlinear empirical model of pore-water pressure and creep. Several other authors noted significant creep effects in landslide deformation and proposed indicators of reactive creep properties using predictive models. paid much attention to the time effect of landslide deformation, believing that the instability of landslides was closely related to the viscoelastic properties of rock masses. Instead, the rheological model should be applied to landslide deformation and long-term stability prediction. When using a general finite element analysis, it is impractical to consider only the elastoplastic constitutive model to simulate the landslide problem. Even when the reservoir and groundwater levels were stable, its deformation continued to increase. For example, the deformation of the Bazimen and Shuping landslides in the China Three Gorges reservoir area showed obvious rheological properties, such as the stepwise Global Positioning System displacement of the surface with a decrease of the reservoir water level. The understanding of the influence of water-level changes on the deformation of reservoir landslides has developed and changed over time. The stability coefficient of the landslide calculated by the strength reduction method, considering the rheological properties, is smaller than the coefficient calculated without considering rheological properties. It can be found that the landslide displacement calculation is significantly smaller when the rheological properties are not considered. A numerical simulation of rheological properties is conducted on a landslide and compared with conventional viscoelastic constitutive results. A strength reduction method that considers rheological properties is proposed. This paper uses FLAC3D, a finite-element software platform, for secondary development and to verify the accuracy of the model and program. In this paper, the three-dimensional state equation of the extended Burgers model is derived based on the creep test results of slip-surface soil and the Mohr–Coulomb elastoplastic model. Soil creep properties are not considered, often rendering inaccurate results. The results show that the numerical simulation curve is in good agreement with the stress-strain curve of the experiments, which shows that the modified Duncan-Chang model has good feasibility and applicability to Guiyang red clay.Landslide deformations have predictable rheological properties, but, when using finite element analysis, only the elastoplastic constitutive equation of soil is considered. (3) VC++ programming language is used to modify Duncan-Chang E-B model in the software of FLAC 3D. Correspondingly, the initial tangent elastic modulus is modified into a three-stage function, and the Duncan-Chang model of Guiyang red clay is obtained and the parameters such as shear strength, failure ratio, tangent Poisson’s ratio and tangent volume modulus are calculated. The curve is composed of three segments which represent the deformation law of the clay samples in compression-shearing process. (2) Based on Duncan-Chang model, the incremental elastic curve is fitted. (1) According to the results of triaxial consolidated drained tests with different moisture content, the damage forms, stress-strain curve, the relationships between pore water pressure and displacement changing with the time are analyzed in detail. Based on Duncan-Chang model, the constitutive model of red clay and its mechanical parameters are studied by laboratory tests and numerical simulation. A large area of China Southwest is covered by red clay, which is a kind of Karst regional special clay with high moisture content, high ductility, large void ratio, low density, poor compaction.
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