Research On Slope Mechanical Parameters Based On Multi-attribute Decision Comprehensive Evaluation Method

As we all know,slope has the characteristics of uncertainty,heterogeneity and changing over time,which easily leads to landslide and other disasters.The mechanical parameters are important indicators for the analysis of slope stability.While the reasonable value of sliding surface mechanical parameters is one of the difficult topics in slope engineering.At present,the methods for determining the mechanical parameters of slope are more and more diversified,such as,in-situ direct shear test,back analysis and calculation,empirical formula calculation and artificial neural network model.With the development of science,many scholars have made some improvements to these methods,but they didn't consider that whether these methods were suitable for a specific slope project.Therefore,it has great practical significance to study how to choose the optimal method of parameters for different slopes.Considering from the analysis of the influencing factors of the methods for determining the sliding surface mechanical parameters and being based on the entropy weights obtained by the entropy method,set pair analysis(SPA)and TOPSIS comprehensive evaluation methods are established to choose the optimal parameters.And comparing the values of SPA method and TOPSIS method in the comprehensive evaluation of methods for parameters.It provides a necessary reference for the selection of reasonable parameter in practical slope engineering.The main contents of this paper are as follows:(1)According to the previous studies,this paper is based on the factors of the slope and methods,considering the influencing factors of methods and combing with the standards to determine the contents of each influence factors,therefore,this paper sets the evaluation criterion of the influencing factors of sliding surface's methods by literature research and standard study.By calculating the importance coefficient and variability coefficient,it is judged whether it is negligible in this project.In order to optimize evaluation criteria of the influencing factors of the methods of sliding surface mechanical parameters should be removed negligible factors;(2)According to the established evaluation index system and evaluation criteria of influencing factors,entropy method is used to calculate the objective entropy weight of each influencing factor index.In this paper,the SPA model and the TOPSIS model are established at the same time.The former is to calculate the identity,the degree of difference and the opposite degree of each method for determining the parameters and linked the three together by the contact degree expression to be linking the three dimensions together;In the case that the comparison result of the connection degree is not intuitive,the relative closeness of each method is compared and directly ranked according to the relative closeness degree to visually indicate the optimal method for determining parameters.The latter shows the optimal method by determining the distance from each merhod to the "ideal solution";(3)In this paper,SPA comprehensive evaluation method is applied to complete comprehensive evaluation of mechanical parameters C and ? of PingDeng County.The results show that indoor test is the method to determine optional parameters of this project.And the result of TOPSIS comprehensive evaluation shows that the inverse analysis method is the best method for determining parameter.At the same time,the results of C?? sensitivity analysis and error analysis show than the error between the indoor test determined by SPA method and the actual value of engineering is the smallest,and the results of SPA is more accurate and reasonable than TOPSIS;(4)Due to the large calculation of evaluation model,the Visual Basic language is used to realize the software development of SPA comprehensive evaluation method.The result of the optimal method for determining parameters can be directly obtained by inputting the relevant parameters of the concrete project.Through the above research,the SPA comprehensive evaluation model was established to select the optimal method for determining parameters.The feasibility of this method was verified through the engineering example.And the software development of the SPA comprehensive evaluation method was realized.It realizes the purpose of saving time,effort and money in parameters selection of the projects.