| It will seriously threaten the development of the national economy and people’s property and life safety,once the dam structure failures.In the design and safety evaluation analysis of dam structure,the effect of dam-reservoir-foundation dynamic interaction and crack-water interaction on the crack propagation,the thermal stress analysis and seepage stress analysis are the key factors needed to be considered.How to evaluate the stress level of dam structure accurately and efficiently is not only a hot issue but also a difficulty both in the academic and engineering circles.The depth of the research on these issues has effected on structure design optimization,safety evaluation in current condition and the decision of reinforce or reconstruction.Therefore,it has great value and significance for the further study on this topic.The scaled boundary polygon method(SBP)is a novel numerical method developed in recent.It not only maintains the characteristic of scaled boundary finite element method,which has semi-analytical displacement/stress solution in the polygon element and do not need a fundamental solution compared with boundary element method.Thus,it is suitable for analyzing problems containing infinite domain and stress singularity.Furthermore,it also has the characteristic of polygon elements in modeling complicated structures flexibly.It will have great advantages especially for the cases needed to be remeshed along with topology changement,such as crack propagation analysis.Based on the main advantages of this method,further research and program improvement are carried out in this paper.It is applied to static and dynamic analysis,seepage analysis,thermal stress analysis and crack propagation analysis of dam structures.The innovative achievements include:(1)The refined static and dynamic analysis model is constructed according to the characteristics of dam structures.To improve the traditional scaled boundary polygon method,it makes use of the isogeometric analysis technique,global-local two steps analysis method and the proposed directly analysis method for the cases with sectional loads on the side-faces.Compared with these improved strategies,it is found that if the strategies can be used skillfully,the accuracy and efficiency of analyzing stress field of dam structures will be improved conspicuously,especially for the region contains stress singularity.(2)The application of scaled boundary polygon method is extended.It is now applied to analyze seepage field,seepage stress field,temperature field and thermal stress field.For the unconfined seepage,an iterative strategy is proposed based on fixed polygon mesh and the reasonable seepage stress analysis procedure based on scaled boundary finite element method is addressed.For the thermal stress analysis,a two steps procedure based on global-local refined analysis is proposed.The numerical examples validate its effectiveness.(3)Based on the scaled boundary polygon method,a novel numerical model is proposed to simulate gravity dam crack propagation.The factors influencing on crack propagation,such as dam-reservoir-foundation interaction,crack-water interaction,contact of crack surface,length of initial crack,assumed crack propagation length and near-fault ground motions,are investigated.The radiation damping of infinite foundation,the water compressibility and the absorption of the reservoir sediments can be considered in the adopted dam-reservoir-foundation model.The roughness of crack surface and flow state of the in-crack water can be considered in the proposed crack-water interaction model.It can prevent mutual embedding of crack surfaces in dynamic analysis.Fully-automatic remeshing can be realized in crack propagation simulation.Through the research on the usual problems of hydraulic structures,the numerical model based on scaled boundary polygon method is well qualified for simulating complicated structures in practical engineering.It has good prospect and potential in application. |
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