Calculation method of stope floor damage depth under the action of confined water pressure

Abstract

The invention discloses a method for calculating the damage depth of the stope floor under the action of the confined water pressure, which comprises the following steps: 1) selecting the calculation range of the model; 2) defining the action ranges and loads of the supporting pressure and the water pressure of the floor distribution form; 3) Define the material properties of the floor rock mass within the calculation range; 4) Set the floor stress component to be the superposition of the additional stress caused by the mine pressure and water pressure and the original rock stress; 5) According to the elastic half-space theory Fu Laman solution and Mindlin’s solution deduced the additional stress components of the floor under the action of support pressure and water pressure; 6) According to the results of the stress solution, the mohr-coulomb criterion with tensile yield was selected to calculate the depth of floor failure, and the shear and Depth and extent of tensile failure. Compared with the existing analytical solution method, the present invention considers the effect of the bottom plate's confined water pressure, which is more in line with the actual situation.

Description

technical field [0001] The invention relates to the field of coal mining, in particular to a calculation method capable of considering the damage depth of stope floor under the action of confined water pressure. Background technique [0002] Floor water inrush in coal mining above confined water is one of the major disasters in my country's coal mining. How to avoid floor water inrush has always been a technical problem in the safe mining of coal mines in my country. [0003] When the coal seam is mined, under the combined action of the mine pressure and the underlying confined water, when the waterproof floor reaches or exceeds the extreme value of the rock mass strength of the floor, the rock mass within a certain range of the floor of the working face will be damaged. If the zone communicates with the underlying confined aquifer of the coal seam, the floor water inrush will be formed. Therefore, the accurate calculation of the failure depth of the stope floor is an impor...

AI Technical Summary

Problems solved by technology

[0005] Most of the analytical solutions for the failure depth of the coal mining floor above confined water only consider the effect of the support pressure of the working face, and do not consider the stress redistribution and failure mechanism of the floor under the influence of the confined water pressure.

As we all know, in the compression section under the support pressure and the expansion section of the gob pressure relief, the bottom plate will inevitably increase its compression deformation and expansion under the action of water pressure, so that the shear damage and tensile force of the bottom plate will increase. The extension damage range becomes larger

Therefore, compared with the failure of the floor without considering the water pressure, the solution of the stress distribution and failure depth is also more complicated

Moreover, the above research results only considered the shear failure of the bottom plate, and did not consider the form of tensile failure, which is obviously unreasonable.

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