Strength test method for jet grouting reinforcement coal body

Abstract

The invention discloses a strength test method for jet grouting reinforcement coal body. The strength test method comprises the main steps of firstly, fabricating a coal matrix with a through hole ina middle part, filling a coal slurry mixed liquid in the through hole, and forming a sample after pressure maintenance for a certain time; secondly, vertically placing the sample in two straight cutting boxes arranged in a upward-downward way, applying a press head onto a top surface of the sample, adjusting vertical stress to a setting value, slowly moving a shearing box arranged below by displacement control, acquiring a shearing force in real time, stopping testing after the sample is completely cut, and recording parameters, a peak shearing force, a residual shearing force and the like; and finally, calculating a peak of the coal body, residual cohesion and an internal friction angle by data fitting. By setting contrast experiment, the strength change of the reinforced coal body afterjet grouting is evaluated; and a true coal body is used as a matrix, the strength between structural surfaces after coal body grouting can be quantitatively calculated, and a test result is more approximate to a site condition.

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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