Overlying strata dynamic position prediction method considering mining rock mass crushing and swelling performance

Abstract

The invention discloses an overlying strata dynamic position prediction method considering mining rock mass crushing and swelling performance, and the method comprises the steps: simplifying upper andlower rock groups of a separation layer under the maximum development height of a caving zone into a two-end clamped beam model for analysis and calculation by considering the difference of separation layer mechanical models of different strata caused by the rock mass crushed expansibility; For the separation layer above the maximum development height of the caving zone, the upper rock group of the separation layer is simplified into the two-end clamped beams, the lower rock group of the separation layer is simplified into the Venturi elastic foundation beams for analysis and calculation, andcompared with a traditional method, the mechanical model selected by the method is more reasonable. According to the method, the criterion of disappearing of the separation layers at different positions is given, and the method can be used for predicting the dynamic development position of the separation layer of the roof, so that the development position of the overburden separation layer corresponding to the working face footage can be predicted more accurately, and basic research and prevention work of rock stratum movement and related secondary disasters can be better served.

Description

technical field [0001] The invention relates to a method for predicting the development position of a detachment layer, in particular to a method for predicting the dynamic position of a detachment layer of overburden considering the crushing property of mined rock mass, and belongs to the technical field of underground safety production. Background technique [0002] After the coal seam is mined, a goaf will be formed, and the original stress of the overlying rock and soil layer in the goaf will be redistributed during the mining process of the coal seam, resulting in certain regular deformation and failure. According to the damage degree of the rock and soil mass after coal seam mining, the overlying rock and soil layer after mining can be divided into: bending subsidence zone, fracture zone and caving zone or collapse zone from top to bottom. The overlying rock and soil layer on the coal seam is unbalanced due to mining, and the layer caving begins to occur from the immed...

AI Technical Summary

Problems solved by technology

However, there are many deficiencies in this traditional theoretical method, such as: (1) The method defaults that the "composite beam" composed of rock formations will not be supported by the broken rock mass below when it migrates to the goaf, that is, it does not consider the rock mass. Differences in mechanical models of abscission in different layers caused by body disintegration

(2) The movement form of the roof overlying rock is the bending deformation failure in the unit of "rock group" composed of single or multi-layer rock layers, and the separation layer can only occur at the contact surface of adjacent "rock group"; this method will Each layer of overlying rock on the roof is used as a separate object for comparison of mechanical properties, which undoubtedly leads to more deviations in the prediction results

(3) With the mining of the coal seam, the roof abscission layer presents an evolution process of horizontal distribution and vertical dynamic jump. This method does not consider the influence of the working face footage on the stability of the absorptive layer of the roof overlying rock, and cannot predict the closure or disappearance of the absorptive layer. That is, it is impossible to predict the dynamic position change of the development of the roof overlying rock detachment layer

Therefore, this traditional prediction method cannot predict the dynamic development position of the abscission layer very accurately, that is, it cannot predict the development position of the abscission layer of the roof overlying rock corresponding to a certain footage of the working face

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