Evaluation of the large deformation grade cloud model of surrounding rock based on combination weighting method

Abstract

On the basis of the analytic hierarchy process (AHP) and entropy weight method, combined with the statistical results of large deformation under the complex geological conditions of Galigongshan tunnel, the grade cloud model evaluation method of the large deformation of surrounding rock is proposed. Its influencing factors are considered to select the strength stress ratio, maximum principal stress, elastic modulus, and uniaxial compressive strength as evaluation indexes. The weight of each index in the evaluation of large deformation is determined through AHP and the entropy weight method. Meanwhile, the combined weights of each influencing factor index are obtained by the optimal combination weighting method of maximizing the sum of squares of total deviation. Aiming at the uncertainty and randomness of the large deformation evaluation of tunnel surrounding rock, the numerical characteristics of a normal cloud model are used to calculate the determination of the evaluation index, and the evaluation results of the large deformation grade of surrounding rock are obtained. In this study, this method is applied to the large deformation evaluation of the surrounding rock of Galigongshan tunnel engineering. Compared with the results of the fuzzy hierarchical comprehensive evaluation method, the model evaluation method established here is more feasible. It combines subjective and objective weights to obtain a reasonable weight in the practical engineering application of significance, as large deformation provides a reliable reference for the prediction and prevention of disasters.