Interval confined-unconfined water inflow forecasting formula

For the issues that the uncertainty exists in calculating the mine inflow, this study starts from the perspective of interval uncertainty. Based on the non-probabilistic set method, the interval analytic expression of confined-unconfined water inflow is deduced for different conditions by using empirical formula to calculate the influence radius and according to the observed data to give the influence radius. The interval response of water inflow under the interval uncertainty of parameters is quantitatively depicted, and the shift of calculating formula from the deterministic type to the type of interval uncertainty is realized. By comparing the upper and lower limits of the real interval values which are obtained by MC with the upper and lower limits of the interval value which are calculated with the deduced formula, the allowed change rate of the corresponding variables is given respectively when the absolute value of relative error of the results is controlled within 5% and 10% which are calculated with the two interval water inflow formula. The results show that the allowed change rate of the variable is 0.18 (0.08) and 0.28 (0.12), respectively, when the relative error of the maximum (minimum) water inflow which are calculated with the first formula is 5% and 10%, and the allowed change rate of the variables is 0.08 (0.05) and 0.12 (0.08), respectively, within the same condition which are calculated by the second formula. Under the identical error requirements, when the allowed change rates of the maximum values calculated with the two formula are higher than that of the minimum values, it is beneficial to calculate the upper limit of the mine inflow. This paper provided a new way for the uncertainty research on the mine inflow calculation.