Concrete Face Rockfill Dam Fuzzy Finite Element Stress And Deformation Analysis

It is well known that the modern concrete face rockfill dams (CFRD) have somany advantages such as small amount of dam body, short construction period andlow project cost that recent years witness a gteat development of CFRD in China.However, the construction of CFRD is guided more by experiences than theories,therefore, much efforts is needed in the theory study of CFRD in which one of thedifficulties is, in the computing and analyzing of CFRD, the existence of a plenty ofuncertainty factors. those factors cannot be taken into account in traditional FEM,while the fuzzy finite element method (FFEM) can make up this defect. Moreover, theexpert's experiences can be considered in FFEM, which will be very useful to theconstruction of water dam that require much practices.In this paper, the variational method in mechanics of elasticity is extended so thatthe fuzzy variants can be considered, from which the fuzzy equilibrium equations areestablished. And then the solving of fuzzy equilibrium equations is transformed intoan optimizing problem. In this way, the FFEM can deal with not only linear problemsalso non-linear ones and many kinds of fuzzy factors can be considered without theneed of complex mathematical analysis. Based on the theories and methods above, a2-D FFEM program, which can simuIate the construction and impoundment of CFRD,is developed, and examples show that the program is reasonable and reliable.Furthermore, the program can be used widely for no limit to the type of subordjnatefunctions. Also, a program for the mesh auto formation and display is developed as apreprocessing system of FFEM program. Taking Tianshengqiao I CFRD as anexample, parameters sensitivity of rockfill material and fuzzy displacement of CFRDare mainly computed and analyzed, and the computing results contain muchinformation through which the displacement's scale of any nod and its subordination(possibility) are obtained. This can help the engineering decision-making. It can beshow from engineering computing that the sensitivity of mechanical parameters aredifferent between horizontal displacements and vertical ones, and that the bodysubarea of CFRD can produce strong effects on parameters' sensitivity Also, as far asfuzzy displacements is considered, the fuzziness of mechanical parameters can exertan extreme effects on displacements (especially horizontal direction in upstream),horizontal and vertical, so that it should not be ignored.