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Date of Publication:2022-10-10

Journal:农业工程学报

Issue:8

Page Number:176-182

ISSN No.:1002-6819

Abstract:Landslides occur frequently and lose greatly, especially in China, and always have the characteristics of large scale, complex mechanism as well as serious destruction. It is important to assess landslide stability for understanding the evolution process of the landslide. In this paper, the recognition method of variable fuzzy pattern was applied to evaluate landslide stability. The method was based on the theory of variable fuzzy set, relative membership degree function and multi-level and multi-index evaluation unit system on landslide stability which included both the qualitative and quantitative factors. In order to overcome the limitations of the fuzzy comprehensive evaluation method which had a maximum membership degree, the relative membership degree function and the grade eigenvalue were used in the recognition method of variable fuzzy pattern. For the complexity and fuzziness of landslide system, the multi-level and multi-index evaluation unit system was set up by selecting 4 levels and 17 factors. In the purpose of confirming the fuzzy weights, the comprehensive evaluation of the three-level weights was adopted and the method of dualistic factor contrast combined with fuzzy mood operator was also used. The recognition method of variable fuzzy pattern was adopted to appraise the stability of Danba Landslide, Laojinshan Landslide and Yankou Landslide, and the results of the evaluation were consistent with the investigation. Depending on the different evaluation results of the Danba Landslide in 4 periods, the impact of the stability of Danba Landslide was semi-quantitatively evaluated. The stability declined at first and later improved from 1980s to 2007, and was in the most unstable state from March 2004 to March 2005. By comparing the stabilities of Danba Landslide during 1999-2004 and from March 2004 to March 2005 with that during 1980s-1998, the stabilities declined by 6.4% and 10.1%, respectively. And the stability of the landslide in period d (from March 2005 to 2007) improved by 4.7%compared with period c (from March 2004 to March 2005), and decreased by 5.2%compared with period a (from 1980s to 1998). In order to compare present method with fuzzy comprehensive evaluation method, two cases of Danba Landslide were studied in period a (from 1980s to 1998) and d (from March 2005 to 2007). The results evaluated by variable fuzzy evaluation method and fuzzy comprehensive evaluation method were both in Level three. The stability eigenvalues of Danba Landslide in period a and d were evaluated by variable fuzzy evaluation method, and the two eigenvalues were 3.27 and 3.44, respectively. Stability of Danba Landslide in period d was worse than in period a, although they belonged to the same grade. In this study, the average eigenvalue which could make the error smaller was obtained. Actually, the eigenvalue was obtained by a series of different parameters. Therefore, the recognition method of variable fuzzy pattern is more feasible and reliable, and it is much stricter in the superior grade. Just as any other traditional evaluations, the recognition method of variable fuzzy pattern has a difficult problem that the qualitative factors cannot be completely quantified. But the qualitative indices can be converted into semi-quantitative indices by the recognition method of variable fuzzy pattern. Besides, the reliability of evaluation results can be guaranteed because of reasonable selection of evaluation indices and the accuracy of specific numerical indicators. The recognition method of variable fuzzy pattern is a promising evaluation approach in Landslide stability assessment, and it can provide scientific basis for landslide disaster prevention and control.

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