Numerical simulation method for studying gob-side entry driving surrounding rock stress

Abstract

The invention belongs to the field of coal mine safety mining, and particularly relates to a numerical simulation method for studying gob-side entry driving surrounding rock stress. Comprising the following steps: S1, selecting physical parameters of a plurality of rock stratums in a roadway, and constructing a model; s2, selecting a part of on-site working surfaces to carry out an excavation simulation experiment, and analyzing the distribution change condition of stress in a rock stratum; s3, comparing the correctness of the model according to a mechanical measurement result and a field monitoring result; and S4, using a simulation method to carry out an excavation simulation experiment on the whole field work station, and analyzing the change condition of the stress in the rock stratum.

Description

Technical Field

[0001] The invention belongs to the field of safe mining of coal mines, and in particular is a numerical simulation method for studying surrounding rock stress in gob-side tunneling. Background Art

[0002] Gob-side tunneling is a support technology in coal mining, which retains the coal pillars in the coal layer to form an empty tunnel. As the demand for coal gradually increases, the development of gob-side tunneling plays a key role in the utilization of coal resources, so its safety and stability will directly affect the production efficiency of the mine and the safety of workers.

[0003] In underground mining projects, a large number of vertical shafts, inclined shafts and tunnels need to be excavated to enter the ore body, and then larger cavities are formed in the rock mass during the mining process. This process breaks the initial stress balance of the original rock mass, causing the stress of the surrounding rock mass to be redistributed and reach a new equilibrium state. However, after mining activities, the rock mass stress will be redistributed unevenly, and high stress will appear in some areas around the mining space. This situation will cause serious deformation of the tunnels and working faces in use, and the cross-section will shrink significantly, thus affecting subsequent mining work.

[0004] Based on this, how to provide a device that can detect the stress condition of tunnel rocks is a problem that technical personnel in this field need to solve. Summary of the invention

[0005] The technical problem to be solved by the present invention is to simulate the stress conditions of tunnel rocks. However, the existing technology fails to fully consider the differences in physical and mechanical properties of different rock strata and cannot truly reflect the mechanical response of layered surrounding rock tunnel excavation. A numerical simulation method for studying the stress of surrounding rock in gob-side tunneling is provided.

[0006] The present invention adopts the following technical scheme: a numerical simulation method for studying surrounding rock stress of goaf-side tunneling, comprising: S1: Select the physical parameters of several rock layers in the tunnel and construct the model; S2: Select some on-site working surfaces to conduct excavation simulation experiments and analyze the distribution and changes of stress in the rock formation; S3: Compare the correctness of the model based on the mechanical measurement results and field monitoring results; S4: Use simulation methods to conduct excavation simulation experiments on the entire on-site work and analyze the changes in stress in the rock formation.

[0007] In some embodiments, in step S1, the rock formation comprises: Coal seams, the physical parameters of coal seams include density, bulk modulus, shear modulus, cohesion, internal friction angle and tensile strength; Mudstone. The physical parameters of mudstone include density, bulk modulus, shear modulus, cohesion, internal friction angle, and tensile strength; Siltstone. The physical parameters of siltstone include density, bulk modulus, shear modulus, cohesion, internal friction angle, and tensile strength; Medium sandstone. The physical parameters of medium sandstone include density, bulk modulus, shear modulus, cohesion, internal friction angle and tensile strength.

[0008] Compared with the prior art, the present invention has the following beneficial effects: The present invention analyzes the data of the model according to the Mohr-Coulomb yield criterion, studies the changes of the minimum and maximum stresses of the coal seam during the mining process, and when the coal seam will deform. According to the physical component parameters in the working face coal mine, the model is constructed, a certain coal seam is selected for simulation experiments and field implementation, the field changes and model changes under the same conditions are obtained, and the correctness and feasibility of the model are analyzed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 For coal mine working face; Figure 2 This is a schematic diagram of the FLAC3D model; Figure 3 It is a flow chart of the numerical simulation method in the embodiment of the invention. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0011] like Figure 3 As shown, a numerical simulation method for studying surrounding rock stress of gob-side tunneling is characterized by comprising: S1: Select the physical parameters of several rock layers in the tunnel and construct the model.

[0012] In step S1, the rock formation includes: Coal seams, the physical parameters of coal seams include density, bulk modulus, shear modulus, cohesion, internal friction angle and tensile strength; Mudstone. The physical parameters of mudstone include density, bulk modulus, shear modulus, cohesion, internal friction angle, and tensile strength; Siltstone. The physical parameters of siltstone include density, bulk modulus, shear modulus, cohesion, internal friction angle, and tensile strength; Medium sandstone. The physical parameters of medium sandstone include density, bulk modulus, shear modulus, cohesion, internal friction angle and tensile strength.

[0013] The present invention selects the working face of Baoli Fengyu Coal Mine as the background to establish the model. Figure 1 shown.

[0014] The mechanical parameters of the coal and rock formations in the model are calculated based on previous experience, as shown in Table 2-1. The model calculation uses the Mohr-Coulomb yield criterion: Where: , are the maximum and minimum principal stresses, c and are the cohesive force and internal friction angle of the rock, respectively. When fs < 0, the material will fail in shear. The materials used in the model are shown in Table 1.

[0015] Table 1 Mechanical parameters of coal and rock formations in the model Combined with the 32 上 03 working surface and 32 上 05 Coal seam geology and mining conditions at the working face, application of FLAC 3D Numerical computing software, for modeling, such as Figure 2 shown.

[0016] The model includes: coal mine working face. 1 Simulation layout is working face mining → 2 Excavation of transport drift → 3 Mining of working face, analysis of the damage characteristics of surrounding rock at each stage → 4 Combination of on-site implementation and simulation experiment to analyze the feasibility of the model.

[0017] S2: Select part of the on-site working surface to conduct excavation simulation experiments and analyze the distribution changes of stress in the rock strata.

[0018] S3: Compare the accuracy of the model based on the mechanical measurement results and field monitoring results.

[0019] S4: Use simulation methods to conduct excavation simulation experiments on the entire on-site work and analyze the changes in stress in the rock formation.

[0020] First, a coal seam in the coal mine working face is selected for excavation. According to the Mohr-Coulomb yield criterion, the present invention performs data analysis on the model to study the changes in the minimum and maximum stresses of the coal seam during the mining process, and when the coal seam will deform. According to the physical component parameters in the coal mine at the working face, the model is constructed, and a coal seam is selected for simulation experiments and field implementation to obtain the changes in the field and the model under the same conditions, and analyze the correctness and feasibility of the model.

[0021] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A numerical simulation method for studying surrounding rock stress in gob-side tunneling, characterized in that: include: S1: Select the physical parameters of several rock layers in the tunnel and construct the model; S2: Select some on-site working surfaces to conduct excavation simulation experiments and analyze the distribution and changes of stress in the rock formation; S3: Compare the correctness of the model based on the mechanical measurement results and field monitoring results; S4: Use simulation methods to conduct excavation simulation experiments on the entire on-site work and analyze the changes in stress in the rock formation.

2. The numerical simulation method for studying surrounding rock stress of goaf-side tunneling according to claim 1 is characterized in that: In step S1, the rock formation includes: Coal seams, the physical parameters of coal seams include density, bulk modulus, shear modulus, cohesion, internal friction angle and tensile strength; Mudstone. The physical parameters of mudstone include density, bulk modulus, shear modulus, cohesion, internal friction angle, and tensile strength; Siltstone. The physical parameters of siltstone include density, bulk modulus, shear modulus, cohesion, internal friction angle, and tensile strength; Medium sandstone. The physical parameters of medium sandstone include density, bulk modulus, shear modulus, cohesion, internal friction angle and tensile strength.

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