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Abstract Based on the unascertained measurement theory and the actual characteristics of the project，an unascertained measurement classifying model to predict the possibility and classification of rockburst is established. Firstly，the main factors of rockburst，such as the maximum tangential stress of the cavern wall sθ，uniaxial compressive strength sc，uniaxial tensile strength st，and the elastic energy index of rock Wet，are taken into account in the analysis. Three factors，the stress coefficient of rock sθ/sc，the brittleness coefficient of rock sc/st and the elastic energy index of rock Wet are taken into account from the aspects of the causes of rockburst and its characteristics in the analysis，according to the unascertained factors of classification prediction of rockburst. Then the unascertained measurement function is obtained based on the initial data for the analysis of the rockburst of eighteen rock projects around the world. The problems of uncertain factors in classification prediction of rockburst are solved by qualitative analysis. The index weights of all factors are calculated using entropy theory. Finally，the evaluation results of the prediction and classification of rockburst are obtained on the basis of the rule of incredible recognition. It indicates that the unascertained measurement assessment results agree well with the actual records，and are consistent with those of the fuzzy synthetic evaluation method，the attribute synthetic evalution method，the grey optimization model and the matter-elements method. Therefore，the feasibility of the proposed model is validated. Furthermore，a case of Qinling tunnel is analyzed by using the proposed method in order to study the effectiveness and feasibility of the model. The results show that the prediction results agree well with the practical records，which prove that the unascertained measurement model is effective and available，and can be applied to the prediction for the possibility and classification of rockburst in underground engineering.
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Received: 08 January 2009
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