Studies On Modeling Of Dam-foundation System And The Analysis Based On SBFEM

The purpose of this paper is based on Scale Boundary Finite Element Method(SBFEM),which only needs to solve the domain surface decomposition and radial analysis characteristics,and BIM technology has high-efficiency and high-precision characteristics in 3D geometric modeling,proposes for arch dam-foundation-slippery block system geometry modeling,grid dispersion,calculation and analysis of the solution strategy to improve the degree of automation of model generation,reduce the model of discrete workload,the use of scale boundary finite element can performs overall stress and stability analysis of arch dam-foundation-slider body system model,and can improve computational efficiency with guaranteed accuracy.Therefore,this method has the following advantages: The geometric model of arch dams and river valleys can be accurately established with BIM technology;Since only the SBFEM solution on sub-domain surface is discretized,the grid discrete workload is small;through the scale finite element analysis,the three-dimensional problem is reduced to two-dimensional processing,which reduces the amount of calculations.At the same time,the impact of the contact between the slider body and the dam foundation on the stability of the arch dam abutment can be considered.The main contents and results of this article are as follows:(1)The establishment of the geometrical model of surfaces of canyon and arch damThe points of the topography of the canyon can be obtained from the CAD file and the surface of canyon can be formed by these points by making use of the Revit software.According to the shape of arch dam,the surface of arch dam can be established in Dynamo software.The arch dam model was imported into Revit,and the arch dam and foundation position were adjusted to form a whole geometric model for the dam-foundation system which is closely resembled the real arch dam-foundation.Then the geometric model was imported into ANSYS and provide the necessary informaton of area in order to utilize the powerful mesh function in FEM software ANSYS(2)Established the discrete grid model for SBFEM analysis and static analysis submodule suitable with SBFEMUsing the geometric information of arch dams and canyon that have been imported into ANSYS software to form the overall geometric model of the arch dam-foundation system.Then,the overall model is cut to form a number of scale boundary finite element solution sub-domains,and the boundary surface of the sub-domain is discretized by 2D elements to form a subdomain superelement that can be used for scale boundary finite element analysis.On the existing SBFEM basic program,preprocessing,assembly of the different subdomain stiffness matrices,body load and water pressure load and contacts soft subroutines are coded.(3)The static structural and stability analyses are performed simultaneously by SBFEM for the dam-foundation-sliding block systemFor the static load case,the overal dam-foundation-sliding block system are analyzed by SBFEM.By taking into consideration of the contact between sliding-block and rocks,the stability of the sliding block and its effects on the response of dam structure can be obtained.For dam-foundation system without sliding block,as compared to FEM,the distribution and values of the displacements in dam body agree well with each other.For the dam-foundation-sliding block system,the safety factor of sliding block by rigid limit equilibrium method is less than the tolerance one.The contact status obtained by SBFEM for the sliding surface are all in sliding state and show that the sliding block will sliding loaded by self-weight and water pressure.So,it is demonstrated preliminarily that the method proposed in the frame work that the structural and stability analysis perform simultaneously to assess the stability of dam abutment and sliding block is feasible.