Reliability Analysis Of Anti Sliding Stability Of Gravity Dam Foundation Based On Fuzzy Mathematics

Anti sliding stability of gravity dam is very important in the design of gravity dam project, we usually adopted safety coefficient method and partial coefficient method to evaluate its stability,But in practical engineering, there are not only randomness but also fuzziness.Due to the limitations of traditional methods can not fully reflect the actual situation of the project, this paper based on the fuzzy mathematics theory to analyze the stability of the dam foundation stability is analyzed.The main results are as follows:(1)Combined with an engineering example,the sensitivity analysis of the friction coefficient and the cohesive force to the stability of the dam foundation is carried out.The value of friction coefficient should be in the middle, then take the suggested values of lower cohesion and apply it to the calculation of.On the basis of summarizing the previous scholars' research.Reliability analysis of three random variables with the best sensitivity is proposed,which is used as a constant process to simplify the calculation process.(2)Based on the improved stochastic reliability theory,several different reliability analysis methods were used to calculate the stability of dam foundation under different distribution of random variables.Several commonly used reliability calculation results are not very large,what can be a good reflection of the actual project, and in the range of target reliability.The case shows that the numerical example satisfies the requirements of anti sliding stability of dam foundation.With the decrease of correlation coefficient, the reliability of random variables is increasing, and the correlation between random variables has a great influence on the reliability of the structure,We should deal with the related problems in the practical project, so as to achieve a win-win economic and security.(3)The emphasis of this paper is based on the fuzzy mathematics theory to establish three kinds of fuzzy risk calculation models of dam foundation stability:horizontal section method,improved fuzzy reliability method and improved fuzzy reliability method two.Level cut product result of income tax law for a range, which indicates that the fuzzy reliability than traditional random reliability that either mutant forms can conform to the project actual situation.On this basis, in order to better analyze the fuzzy reliability of the dam foundation,two improved fuzzy reliability method is proposed to analyze and calculate.We use the smaller membership function failure criterion, the fuzzy random variables by level cut product processing, according to the actual choice of the most appropriate value(generally take the middle value) as fuzzy reliability value.The results obtained by the improved method are smaller than the upper and lower values of the results obtained by using the horizontal section method.Because the membership function of the failure criterion is considered, the accuracy is higher, and the improved method is more reasonable.By means of mathematicalmethod, the fuzzy random variables are quantified and the failure criterion is treated by partial small membership function.The method is simple, practical, stable fuzzy reliability can better meet the actual engineering of gravity dam is calculated by this method, in order to solve the problem of fuzzy reliability provides another way.But the result of this method is a reliable value rather than a fuzzy range.By contrast, the value falls within the scope of the horizontal intercept method and the improved fuzzy reliability method, and the difference between them is small, and it can be used as a means of evaluation.In general, this paper analyzes the randomness and fuzziness of the stability against sliding of gravity dam foundation.A comprehensive evaluation is made on stability and reliability of gravity dam foundation and it can provide guidance for engineering practice.