A method for testing the strength of coal body reinforced by jet grouting

Abstract

The invention discloses a method for testing the strength of a coal body reinforced by rotary jet grouting. The main steps are: making a coal matrix with a through hole in the middle, filling the through hole with a coal slurry mixture, keeping the pressure for a period of time, and then forming Then place the sample vertically in two direct shear boxes arranged up and down, and apply the indenter to the top surface of the sample, adjust the vertical stress to the set value, and slowly move the lower shear box with displacement control. Cut the box, collect the shear force in real time, stop the test after the sample is completely sheared, record the displacement, peak shear force, and residual shear force parameters; finally, calculate the peak value and residual cohesion of the coal body through data fitting and internal friction angle. By setting up a control experiment, the strength change of the coal body after jet grouting reinforcement is evaluated. The invention uses the real coal body as the matrix, can quantitatively calculate the strength between the structural surfaces of the coal body after grouting, and the test results are closer to the field conditions.

Description

technical field [0001] The invention relates to a method for testing the strength of a reinforced coal body, in particular to a method for testing the strength of a coal body reinforced by jet grouting, and belongs to the field of mining engineering. Background technique [0002] Due to the influence of geological structure, deep coal seams are often broken, loose and difficult to form. When the roadway is excavated in this type of stratum, it is very easy to cause roof collapse, large deformation of the two sides and other phenomena that are not conducive to production. At present, in order to prevent the deformation of the coal seam roadway, most mines adopt the combined support methods of frame shed and wall followed by grouting, anchor net cable joint support or anchor cable injection, but practice shows that these methods are often difficult to control the loose and broken enclosure. Rock deformation, frequent accidents. [0003] In recent years, the proposed method o...

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Problems solved by technology

However, this method is still in the qualitative application of engineering, and lacks quantitative evaluation. There is currently a lack of quantitative method research on the strength improvement of the coal body after rotary grouting reinforcement, the specific increase, and the mechanism of rotary grouting reinforcement.

[0004] Considering that the traditional combined control method is difficult to control the loose coal roadway, the pre-grouting with rotary grouting can form a good load-bearing structure and achieve good results. However, at this stage, there is a lack of quantitative evaluation of the coal body after rotary grouting reinforcement. strength properties

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