Shallow buried weak-cementation top plate working face overlying strata zoning dividing method and application

Abstract

The invention discloses a shallow buried weak-cementation top plate working face overlying strata zoning dividing method and application. Firstly, the rock stratum fracture condition is objectively analyzed according to the relationship between the maximum tensile stress borne by all rock stratums and the ultimate stress and the relationship between the ultimate deflection and the separation layeramount; secondly, rock stratum layer positions where cracks are produced are objectively analyzed according to the maximum deflection generated when a rock stratum weak-cementation rock stratum at the upper portion of a fracture rock stratum produces cracks and the ultimate deflection and separation layer amount generated during fracturing, and how much zones the shallow buried weak-cementation top plate working face overlying strata is divided can be judged accordingly; the judgment process is based on real calculation data, no artificial factor is doped in the judgment method, development of a diversion fissure zone is highly accurately predicted, and a guiding effect on the field is truly achieved. By comparing the development height of a complete fracture zone of the working face overlying strata rock stratum or the highest range of an overlying strata crack damage zone with the position of a water-bearing stratum, whether a working face can achieve water retention exploitation ornot can be accurately evaluated, and a basis is provided for mine safety work.

Description

technical field [0001] The invention relates to a method for zoning the overlying rock in the mine stope, in particular to the method for zoning the overlying rock in the working face of the shallow buried weakly cemented roof, which can be used for the arrangement of gas drainage boreholes and the water-conducting zone of the overlying rock in the working face evaluation of. Background technique [0002] The mobile failure of overlying rock is usually divided into "three zones" in the vertical direction, namely the collapse zone, fault zone and bending zone. The height of the caving zone mainly depends on the mining height and the crushing property of the overlying rock, usually 3 to 5 times the mining height, while the fault zone depends on the amount of separated layers between the rock layers and the mechanical strength of the rock itself, and is generally 3 to 5 times the mining height. 10 to 15 times. Highly accurate division of the "three zones" of the roof has a gr...

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Problems solved by technology

However, these methods also have certain problems. The empirical method lacks a theoretical basis, and the similar simulation and numerical simulation methods often greatly simplify the actual situation on the spot, making it difficult to apply the results to the field.

The vertical borehole observation method comes from direct observation of the site, but it also has its own shortcomings

For example, it has the following disadvantages: First, due to cost control on site, there are few drill holes available to observe the roof stratification, and the actual height of the roof stratum often varies greatly due to differences in structure and lithology, which causes drilling problems. Second, the objects of borehole observation are mainly macroscopic cracks, so the vertical borehole observation method is often used more often in determining water-conducting fracture zones, but cannot be well applied to roof zoning. Further refinement and deformation feature determination on

Chinese Patent Publication No. CN108119142A discloses a "five-map-three-zone-two-partition" water-retaining coal mining method. The technologies disclosed in these two documents all need to be drilled in advance. The buried weakly cemented roof has low strength and poor integrity, and is prone to hole collapse, which is not conducive to drilling and extraction, affects monitoring data, and leads to inaccurate judgment of the height of the overburden caving zone and water-conducting fracture zone in the stope, which cannot be scientifically determined. Guidance on site

(2) The existing patent CN108733964 A discloses a method for predicting the development height of water-conducting fissure zones in the overlying strata of short-wall block coal mining. The invention determines the mining range and the physical and mechanical parameters of the coal strata through field investigations and laboratory experiments; Then, with the help of 3DEC numerical simulation software, the relationship between the main controlling factors and the development height of the water-conducting fracture zone was obtained; finally, MATLAB was used to conduct nonlinear regression analysis on the simulation results of the water-conducting fracture zone height, and finally the prediction short-wall block segment formula was established The model of the development height of the water-conducting fracture zone in the coal mining overlying rock, but the numerical simulation method is used in this invention to study the development height of the water-conducting fracture zone, because the result of the numerical model depends entirely on the modeling method, input parameters, model result verification, etc. In many aspects, the simulation results are highly subjective and difficult to reflect the real situation, resulting in inaccurate prediction of the development height of the water-conducting fissure zone, and cannot play a guiding role on the site

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