Research and application of early warning method of roadway deformation based on improved grey Verhulst model

In order to solve the problem of inaccurate early warning results of roadway deformation and instability caused by insufficient monitoring data, the improved grey Verhulst model is used to fit and predict the deformation of roadway surrounding rock, and the inflection point and extreme point of displacement change curve are used to determine the risk level threshold of cumulative displacement and displacement rate index; the fuzzy comprehensive evaluation method is used to construct the fuzzy membership function of the early warning index, the weight of the early warning index is determined by the analytic hierarchy process, and the final risk level of roadway surrounding rock deformation and instability disaster is determined by the maximum membership principle. Through the early warning of the deformation and failure of the filling roof in 2233 haulage roadway of Hengda Coal Mine and the No.1 layered vein crossing roadway of 1 018 m section III panel of Jinchuan No.2 mining area, the results show that the improved grey Verhulst model can effectively improve the accuracy of the early warning of roadway deformation and instability disaster under the condition of small sample monitoring data, which has important guiding significance for the early warning of roadway deformation and instability disaster.