Abstract: According to the analysis of coal floor water inrush,four main influencing factors,such as geologic structure,floor mining-induced failure depth coal seam dip angle,hydraulic pressure and aquiclude thick,were regarded as judgment indexes to establish the forecast model of water inrush from coal floor by unascertained measure theory.Based on 14 groups of water inrush data in coal face as training sample,the sample average was set as cluster center,and the weight of judgment indexes was determined by information entropy theory.Through calculating the multi-index comprehensive measurement of sample,the classification of sample was judged by the principle of minimum unascertained measure distance,which was used to forecast the floor water inrush.The forecast model of water inrush was used to make forecast on the other four prediction samples,and the forecast values are the same as the measured values.The results show that the forecast method of water inrush from coal floor based on unascertained measure theory has a good practicability and validity.

Key words: Unascertained measure theory, Floor water inrush, Single index measurement