The Study And Realization Of Three-Dimension Nonlinear FEA Method Of Earth-Rock Dam Due To ANSYS

Rock fill dam is an old type of dam, and it is the highest dam in the world of beenconstructed. It has the advantage of easy to construction, lower cost and the capability tofit for complex geologic setting, and these make it to the dominant type of dam. In theold days, engineers only study the seepage and stabilization of the dam, but nowadays,the stress and displacement compute becoming necessary with the height increasing ofdam. The most effective and accurate measure of study stress and displacement is finiteelement method(FEM), and ANSYS is a good FEM programmer, so this article makeANSYS in fact to compute rock fill dam through its' parameter design language.The most important and difficulty thing in FEM analysis of rock fill dam is thesimulation of constitutive relation, but there is no appropriate model in ANSYS, so thisarticle make use of ANSYS Parameter Design Language(APDL) to performDuncan-Chang E -B model in it. In course of programming, the "kill and active"function module is used to simulate the reclamation process of dam: Firstly, in order tochoose the function of elastic modulus, we must decide the condition of loading orunloading of every dam element through the prescriptive loading and unloadingfunction due to the result of the previous load step. Secondly, we should modify thestiffness matrix of every element by using of the new data of elastic modulus and bulkmodulus in this load step to simulate the constitutive relation of Duncan-Chang E ? Bmodel. Lastly, we compute the model in ANSYS through its' nonlinear equation solver.Before the final result is to be received, a post-treatment programmer has been designedto amend the displacement of dam to accord with engineer.Comparing the result of this programmer with experimentation, we can see thatthey are coincidence, and this programmer has high efficiency and precision. In addition,through a example of a 100 meter height rock fill dam, we can see that the maximumvertical displacement in condition of constructing period is 0.51 percent of dam heightand it located in the middle or third height of dam, and the condition of operating periodis as same as constructing, but its' maximum displacement is 0.53 percent of dam height.From the example, we arrive at a conclusion that the numerical value is appropriate andthe distributing trend of result is reasonable.In the last part of this article, we carry through a three dimension FEM analysis onGuanyinyan mixed dam by this programmer and get some useful result for project plan.