Application of extension theory based on entropy weight to rock quality evaluation

The evaluation of rock mass quality of dam foundation is a complicated decision-making problem,often appearing to be the contradiction between influencing factors and the coexistence of qualitative knowledge and quantitative information. It is necessary to find a new meta-synthesis method which can solve the inconsistent problem of qualitative and quantitative information. Extension theory is used generally to solve such problems. It integrates research objects, evaluation indexes and its value range into a matter element system to research things’ extension nature. Through the application of extension theory, the thought of multiple indexes optimal fusion and matter-element transform, the matter element system of rock quality evaluation of dam foundation is established and the relational degree of the comprehensive evaluation index can be calculated, of which the weight coefficients are determined by using entropy weight method. Then the extension theory based on entropy weight is established. The essay applies the model to evaluate rock mass quality of dam foundation of some hydropower station. The result is highly agreement with the geological report of this hydropower station and precisely reflects the practical engineering.