The Sensitivity Analysis Study Of Gently Inclined Coal Seam Of Surface Subsidence Prediction Model

In recent years, with the rapidly development of the coal industry and the increase of the intensity of the coal mining, the problem of surface subsidence increasingly is promient, because the surface subsidence may produce a series of security problems, such as houses collapsed, the mountain landslide and so on. Studying the sensitivity of the surface subsidence prediction model to reveal the sensitivity change rules of affecting the model predicting has very important theoretical and practical significance for increasing the accuracy, objectivity and scientific nature of the surface subsidence prediction assessment and guaranteeing the validity of the surface damage scope and degree.This study analyse the mining area of subsidence damage scope and degree through local sensitivity analysis and global sensitivity analysis methods, using sensitivity analysis principle based on the model of the gently inclined coal seam of surface subsidence prediction through the probability integral method. The former pays attention to the impact of individual factors or dependent variable in the model, ignoring the influence of the interaction between model parameters or multiple dependent variables on the result of the model output; The latter mainly focus on the influence of the tiny changes of the multiple parameters sensitivity on the model results and the influence of the interaction between the parameters on the model results. The subsidence damage divided into mild, moderate and severe degree of three levels is predicted with the parameters of the comprehensive evaluation coefficient, the coal seam dip Angle, the depth of coal seam mining and the horizontal displacement coefficient in the model for dependent variables to proceed the sensitivity analysis.Based on characteristic data in diggings, this research takes Xingyu coal mine in Pingding shanxi province as an example for the purpose of calculating on parameter required in subsidence prediction model. The Research has found that the surface subsidence prediction model can be ideal method to predict the damage degree of horizontal coal seam or approximate horizontal coal seam, but this method is not applicable for the surface of steep damage prediction because of the larger error; the influence of parametric sensitivity on the model of the maximum tilt value, the maximum horizontal deformation value and the maximum curvature value is larger then the maximum subsidence value and the maximum horizontal displacement; In local sensitivity analysis of the surface damage, the sensitivity of different parameters on the damage degree is different, the influence of the comprehensive evaluation coefficient sensitivity on the surface mild damage is maximum, the influence of the coal mining depth and the coal seam dip angle sensitivity on the moderate damage is maximum, and the influence of the coal thickness sensitivity on the severe damage is maximum; In global sensitivity analysis of the surface damage, based on the parameter set consisting of the multiple parameters the influence of the sensitivity on surface subsidence damage are different, specifically manifested in the influence on the mild and severe damage is maximum and on a total area of damage and moderate damage is stable. This research is expected to provide certain theoretical reference for studying the steep coal seam with subsidence prediction model, and to provide advice for the safe relocation of the coal industry, village relocation within the mining area and the water conservancy facilities layout etc, eliminating the potential safety hazard.