Study on stability classification of underground engineering surrounding rock based on concept lattice-TOPSIS

In order to classify surrounding rock stability of underground engineering efficiently and correctly, a model for classification of surrounding rock stability of underground engineering based on concept lattice and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) was proposed. The surrounding rock of Jinzhou LPG cavern in China was selected as an engineering case for modeling. Considering the general factors affecting the stability of the underground surrounding rock and combined with the actual situation of the project, five indexes, namely, rock quality designation (RQD), saturated uniaxial compressive strength (R-c), integrality coefficient (K-v), longitudinal wave velocity (V-pm), and fractal dimension (D), were selected as the indexes of the stability classification of surrounding rock. Firstly, five indexes were reduced by using the concept lattice theory. By analyzing the two groups of reduction, RQD, R-c, and V-pm were selected as the final classification indexes. Then, the stability of surrounding rock was classified by TOPSIS, and the classification results were consistent with the measured results. Finally, the established model was applied to the stability classification of several other surrounding rocks in Jinzhou LPG cavern. The results show that the classification results using TOPSIS based on concept lattice agreed well with those of fuzzy recognition direct method, fuzzy recognition indirect method, multistage fuzzy clustering method, and rock mass basic quality index (BQ) which based on five classification indexes. The constructed model reduces indexes required by classification of surrounding rock stability and improves efficiency.