Study On Back Analysis,Stability Of Foundation And Safety Monitoring For Concrete Masonry Gravity Dam

Dam safety is very important because the consequence of its failure is catastrophic. As time passing on, all working conditions (such as structure, foundation, environment) of built dams change constantly, and the safe state of dams varies too. Through analysis and back-analysis of dam prototype observation data, we can evaluate its operation situation, gain mechanical parameters of dam and foundation, calculate and analyse strengh and stabilization of dam, generate monitoring index of dam safety, moniter the safe operation of the dam. Back-analysis of mechanical parameter based on concrete dam has been studied very much, but that based on masonry dam has been done very little. In this thesis, some contents on Changzhao Masonry dam are discussded, the main contents are as follow:Firstly, the principal theories and methods to analyze monitory data are illustrated in this thesis, the statistical model, determistic model and hybrid model are introduced in detail. At the meantime, the stepwise regression method and feature are also discussed in this zrticle. All these theories and methods provide support in theory on back analysis of mechanical pharameters and the statistical model of monitor data.Secondly, basic theories and methods of nonlinear FEM analysis and optimization conversion are introduced, with attention being focused on the constitutive relations of elastic and plastic problem and yield criteria, contact nonlinear analysis, complex optimization method and so on.Thirdly, back calculation of mechanical parameters on nonlinear constitutive equation is given in this paper, combined with the Changzhao project. Parameters of constitutive relation of the dam and the founation are obtained by means of complex optimiged conversionmethod with least square solution.Fourthly, on the condition of Changzhao dam having weak surfaces, stability against sliding is studies with ANSYS, a commercial FEM software. Chiefly with limit equilibrium method of rigid body and FEM(including overload method and shear strengh reducing method), stability of Chaozhao dam are calculated, and safety situation of dam and foundation is estimed.Finally, the theory and method of deformation monitoring index are presented. Hybrid model is built, comined with the prototype observation data. Eventually, deformation monitoring index of the dam monolith No. 4 is drafted, that makes managemengt and analysis system of Changzhao dam observation data perfect enough.