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Stochastic Finite Element Method For The Coupled Process Of The Stress Field And The Seepage Field In The Rock

Posted on:2007-07-07Degree:DoctorType:Dissertation
Country:ChinaCandidate:X HeFull Text:PDF
GTID:1100360185487979Subject:Solid mechanics
Abstract/Summary:PDF Full Text Request
The theory of the coupled process of the seepage field and stress field in the rock is a subject concerning the seepage mechanics and the rock and soil mechanics. Based on the equivalence of the parameter of the stress field and the seepage field, the equivalent continuum is a practical and effective model widely adopted, which can be used to research the general distribution of such variance as the pore pressure, the displacements and the stress in the coupled field. The material parameter of the rock is of great variability which can be described with the theory of the random field. Based on the equivalent continuum model and the research of the spatial variation of the material parameter, stochastic finite element method is adopted to simulate the coupled field, and the results of the simulation can reflect the influence of the variance on the distribution of pore pressure, the displacement, the stress ant etc.The main contents of the dissertation includes: 1)the computational methods of the equivalent permeability tensor of the rock considering the intensity, the azimuth, the jaw opening of the fracture is given based on the equivalent continuum model. The method of the equivalence of the mechanical parameter is also given based on the deformation regularity of the normal and shear fracture of the single fracture. 2) Decoupled finite element equation is given and solved by the precise integration algorithm. The stress field and the seepage field are solve separately and the problem of the solution of ill-posed equation and the vibration of the solution process are avoided by the algorithm, which improves the computational speed as well as the precise of the solution. 3) Both the seepage parameter and the mechanical parameter are treated as random field, which is an excellent representation of the spatial variance of the parameter. The normal Krig interpolation algorithm and the extended Krig interpolation are used to the parameter estimation of the stable and instable random field respectively, which guarantees the validity and the unbias of the estimation. 4)Based on the equivalent continuum model and the random field description of the spatial variance of the parameters, the coupled field is simulated with stochastic finite element method, the simulated results represent the distribution characteristic of the field variables such as the pore pressure, the displacements and the stresses. The method presented not only voids the deficiency of the incapability to reflect the influence of spatial variance on the computational results of the certain method but also provides a efficient method to study the sensitivity of the pore pressure, the displacements to the random parameters.
Keywords/Search Tags:coupled process of seepage field and stress field, equivalent continuum model, equivalent permeability tensor, precise integration algorithm, random field, Kriging interpolation algorithm, stochastic finite element method, sensitivity analysis
PDF Full Text Request
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