The Research On The Theories And Methods Of The Concrete Arch Dams Stability

The arch dam stability is the key issue in arch dam design and analysis.This paper is based on ANSYS,a big FEM simulation software.Based on ANSYS,an equivalent stress calculation program is designed,and a visual post-processing techniques for ANSYS results are discussed.The emphasis is put on the abutment stability of the arch dam and the dam body upper-sliding stability.The main contents are as follows:1. The basic theories and methods and their actualize techniques in ANSYS are introduced,which are used for elastic-plastic and nonlinear calculation for rock engineering and hydrostructure engineering FEM analysis.To simulate the arch dam body concrete and the abutment rock,faults and the big fractures,the elements types and the material types in ANSYS are introduced and discussed.2. The stress concentration will present when there are abrupt change of materials or geometry in FEM analysis,so the results can't be used into design directly.To resolve this problem,the equivalent stress theories and their actualize techniques are discussed.An equivalent stress calculation program is programmed,which is programmed using APDL language of ANSYS,then through the analysis of an example,it is proved to be a correct and efficient way.3. The archdam body upper-sliding stability problem is payed more and more attention in recent archdam stability analysis.In this paper,it is researched too.The upper-sliding calculation theories are discussed,and an assurance factor based on these theories is get.Through an example,it is proved to be on the safe side.A FEM analysis model based on ANSYS is present,and it is discussed through an example,too.Through FEM method and the rigid body ultimate equilibrium method,two assurance factor are get.The two results are compared and analyzed.4. The joint develop techniques based on ANSYS and AutoCAD are discussed.The visual ways and techniques of the automatic reduction for archdam results are discussed too.To present these,programs are programmed,which are based on APDL language of ANSYS and VBA language of AutoCAD.Having done these,the visual and intuitive drawing,such as the archdam deforming drawing and the contour and archring deforming drawing are drawed.5. The 3-D nonlinear FEM analysis model of Tianhuaban RCC cupola archdam is built. The equivalent stresses are calculated using self-designed program,and the archdam stress deforming drawings and the arch ring deforming drawing are drawed through the self-designed post processing programs.The automatic reduction of ANSYS calculation results are presented.Using overload method,the integral upper-sliding stability and partial upper-sliding stability of Tianhuaban arch dam are discussed.It proves that the results is appropriate,and it can be helpful for structure design.