The Reliability Analysis Of Arch Dam Based On The Improved Response Surface Method

Arch dam is famous for its reasonable structure and beautiful shape. It is a very superior dam type with the advantages of economic, security, overload ability, good seismic performance and playing the strength of the material very fully and so on. However, the arch dam, which is influenced by many factors from the boundary and external environment, has complex environmental conditions. Once the arch dam is crashed, the consequence is extremely serious. Therefore, the security analysis of the arch dam has been paid high attention and widespread concern from all sectors of the society.Reliability analysis as an important method of arch dam safety evaluation has been widespread concern. Reliability analysis is a kind of the probabilistic and statistical analysis based on a variety of data information. It uses probability method to consider the uncertainty of the influencing factors quantitatively in the structural design. It is based on the theory of probability and statistics to measure whether the structure is safe and reliable. Arch dam is a high-order hyperstatic space shell structure. It involves many variables which have uncertain values in the structural design of arch dam. Consequently, reliability theory can better simulate the actual working state of the arch dam.Because the arch dam which involves many random variables has a complicated structure and its limit state function is highly nonlinear implicit function of random variables, it is very difficult to calculate its reliability accurately.This paper introduces a improved response surface method on the basis of the summarization for the structure’s reliability analysis methods and the latest research progress. Take the stone masonry arch dam of FoWan reservoir for example, the three-dimensional finite element static analysis of this arch dam is done with the help of the AN SYS software. The reliability analysis of this dam body is also done on the basis of its finite element static analysis. The main research work is as follows:(1) Introduce the main calculation methods of the arch dam stress analysis, elaborate the basic principles and steps of the finite element method and emphatically introduce the finite element equivalent stress calculation method and its implementation process in the ANS YS software;(2) This paper establishes the three-dimensional finite element model of this dam by using parametric design language APDL of the ANSYS software and does the static analysis of this arch dam under the design condition. Besides, The stress concentration phenomenon, which is caused by the finite element calculation, can been eliminated by equivalent treatment for the near foundation stress.(3) Introduce the common calculation methods of the structural reliability analysis. According to the arch dam’s characteristics and the example, combined with the improved response surface method and the checking point method to write the program in C＋＋language, the reliability analysis of this dam body is also done based on the stress analysis of this arch dam by using the ANSYS software.(4) Analyze the influence of the variability of random variables on the dam body reliability, point out the main influence factors of the dam body reliability and provide a reference for the arch dam’s design, construction and safe operation.