Finite Element Analysis On Creep Effect Of Reinforced Embankment Deformation Characteristics

Geotextile due to its high tensile strength, high deformation modulus, light weight, corrosion resistance and good permeability characteristics has been widely used in road, hydraulic, geotechnical engineering. Geotextile as one of the reinforced composite soil shows a greater creep property whose stress-strain relationship could be expressed by power-law creep model when working under load. The geotechnical material not only represents obvious rheological properties but also produces plastic deformation with certain stress condition under time-related loads. The constitutive relation of these geotechnical materials could be described by viscoelastic-viscoplastic model or viscoelastic-plastic model. The model consideres both rheological properties of material and plastic yield characteristics of material. What’s more, the plastic parameters could be determined by conventional test. Therefore the article applies FEM method to analysis the deformation characteristics of reinforced embankment. The rheological property of geomaterial is expressed by viscoelastic-Drucker-Prager plasticity model and the creep property of geotextiles is represented by power-law creep model.The main contents include:(1) For the viscoelastic models combined by elements with rheological property cannot be coupled with plastic models by commercial finite element softwares which only calculate viscoelastic models. The article uses integral constitutive relation of incremental superposition algorithm to make viscoelastic model linearized at every time step coupled with plastic yielding Drucker-Prager model;And this method obtains a closed form analytical solution under considering the linear isotropic harden. The strict viscous elastic-plastic model numerical calculation method and the materials consistent tangent matrix are given by this algorithm. The project is finished through the UMAT material subprogram provided in ABAQUS software.(2) The frictional resistance between geotextile and soil can limit soil deformation. The frictional resistance-shear displacement relationship between soil and geotextile presents non-linear characteristics based on the former experimental researchs. This constitutive relation can be described by Goodman contact element with finite element method. And the user-defined frictional subroutines FRIC used in the ABAQUS software can achieve that project.(3) In the process of finite element analysis, two kinds of models were compared and analyzed: not considering the creep effect of geotextile and soil; considering both the rheology of soil and the creep properties of reinforcement, and analyzing the pavement deformation characteristics under longterm load. Finally, the deformation characteristic of highfilled embankment in partial underground minedout area is analyzed.Calculation results show that the situation that considering the rheological property of geomaterials and creep property of geotextiles working under a long-term load can appropriately explain the deformation characteristics of reinforced embankment. The high fill embankments of laying geotextiles can significantly improve the stability of the embankment, observably reduce the displacement of embankment produced by load, effectively improve the ability to resist deformation of embankment.