| The roof disaster of working face is a serious threat to coal mine safety and efficient production.The study of mine pressure and strata control is the basis for predicting stope roof pressure and preventing coal mine disasters.Therefore,the analysis of mine pressure data is of great significance for the prevention and control of roof disasters.Based on the working resistance data of support in 122108 working face of Caojiatan Coal Mine,the resistance increasing characteristics of support are studied in this paper.First of all,the method of image recognition of support pressure cloud image is used to evaluate the incoming pressure strength of working face in different periods,and the analysis method of integration of support working resistance and height is put forward to study the characteristics of mine pressure behavior of working face.Secondly,two pressure cycles were selected to analyze the distribution characteristics of end resistance and increased resistance of the stent before and after pressure.Finally,the characteristics of increasing resistance of support are studied by means of function fitting and homogenizing cycle,the interaction model between stope support and surrounding rock is constructed,and the reason of increasing resistance of support in 122108 working face is analyzed.The research results of this paper are mainly reflected in:(1)By using the method of image recognition of support pressure cloud image,the mine pressure performance intensity in different periods of working face is analyzed quantitatively.The analysis method of the integration of support working resistance and height is put forward,and the law of mine pressure behavior of working face is studied according to many parameters,such as pressure step distance,support cumulative shrinkage,support shrinkage speed and so on.(2)The distribution changes of support end resistance and resistance increase before and after incoming pressure are explored,and the characteristics of roof movement in the coming pressure cycle are revealed: in the inclined direction of the working face,there is an obvious time sequence in the roof movement in stage 1.In stage 2,the end resistance and resistance increase of the support in each area change little,and the roof subsidence is basically synchronous.(3)The method of function fitting and homogenization cycle is proposed to study the resistance increasing process of support.The changes of function types and fitting coefficient before and after pressure are analyzed,and a method for predicting the pressure of working face is put forward.It is obtained that the instantaneous resistance increase rate of support increases with the change of coal mining cycle during the pressure cycle,and the resistance increase rate increases significantly after pressure pressure.It is proposed that the homogenization cycle curve can predict the change of roof pressure after the safety valve is opened,and invert the macroscopic subsidence process of the roof.(4)The roof fracture mechanism of 122108 working face is clarified,and the causes of support resistance increase under two kinds of structures before and after roof fracture are explored.When the roof is not broken,the introduction of the generalized Kelvin model can well describe the slow movement of the roof and the slow increase of the resistance of the support during the non-compression period;there are two types of movement after the roof fracture,and the support is logarithmic in the given deformation stage.the physical meaning of the fitting coefficient C value of this type is clarified,and the resistance of the support increases exponentially or linearly at a given load stage. |
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