Non-uniform load loading test device and method based on elastic-plastic partition of bearing coal pillar

Abstract

The invention provides a non-uniform load loading test device and method based on elastic-plastic partition of a bearing coal pillar, and belongs to the technical field of non-uniform load loading tests. The technical problem to be solved is to provide the non-uniform load loading test device and method based on the elastic-plastic partition of the bearing coal pillar. According to the technical scheme, all rigid pressing strips are arranged according to an elastic-plastic stress partition form of a coal sample, and the arranged rigid pressing strips are fixed by rigid pressing strip clamp front and rear side clamping plates and rigid pressing strip clamp left and right side clamping plates through bolts; the sensing end of each rigid pressing strip is in contact with the coal sample; the detection end of each rigid pressing strip is in contact with the normal hydraulic transmission shaft and the lateral hydraulic transmission shaft; rigid batten clamp fixing shafts are mounted on the outer sides of the rigid batten clamp left and right side clamping plates; the device is applied to the non-uniform load loading test.

Description

Technical Field

[0001] The invention provides a non-uniform load loading test device and method based on elastic-plastic partitioning of a bearing coal pillar, belonging to the technical field of non-uniform load loading test. Background Art

[0002] During coal mining, the overlying coal rock mass in the goaf will form an arching effect, which will cause changes in the force on the coal pillar, causing the coal pillar to bear different stresses in different areas. During the mining process of the working face, the vertical stress distribution characteristics of the coal pillar will change, forming a plastic failure zone (stress reduction zone), an elastic zone (stress increase zone) and an original rock stress zone in the coal pillar. This change in stress distribution is the direct cause of the elastic-plastic zoning of the coal pillar; the maximum plastic zone width of the coal pillar will increase with the increase of the working face depth and the goaf width. Under different goaf widths and working face depths, the stress distribution and plastic zone distribution laws of the coal pillar will also be different, which will affect the elastic-plastic zoning of the coal pillar.

[0003] When a coal pillar with elastic-plastic partitioning is subjected to non-uniform load conditions, its stability will be significantly affected, resulting in uneven distribution of internal stress and deformation, thereby reducing the bearing capacity of the coal pillar and changing its failure mode. At the same time, it affects the distribution law of the deviatoric stress of the bottom plate, causing changes in the creep characteristics and energy evolution law of the coal pillar. In addition, non-uniform loads will also affect the instability mechanism of the coal pillar-roof system. It is necessary to study the stability and mechanical behavior of the coal pillar under such load conditions through mechanical test models and parameter analysis to ensure safety and efficiency in the coal mining process.

[0004] The deformation of the tunnel surrounding rock is a comprehensive reflection of the mine pressure. The elastic-plastic zoning and fracture range of the surrounding rock are determined by the surrounding rock stress and its own strength, which can be used as an important basis for evaluating the stability of the tunnel and determining the difficulty of support. Therefore, a non-uniform load loading test based on the elastic-plastic zoning of the bearing coal pillar is carried out. By studying the law of tunnel deformation and instability, it is of great significance to improve the stability of the tunnel, the recovery rate of coal resources and the improvement of support technology. However, the current test device has a complex structure and high test cost. The demonstration results of the test method have limitations. When the gradient stress level increases or the non-uniform load is complex, the test equipment is difficult to implement and needs to be improved. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the present invention aims to solve the technical problem of providing a non-uniform load loading test device and method based on elastic-plastic partitioning of a bearing coal pillar.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a non-uniform load loading test device and method based on the elastic-plastic partition of the bearing coal pillar, including a plurality of rigid pressure strips, each rigid pressure strip is arranged according to the elastic-plastic stress partition form of the coal sample, and the arranged rigid pressure strips are fixed by the front and rear side clamps of the rigid pressure strip clamp and the left and right side clamps of the rigid pressure strip clamp through bolts;

[0007] The sensing end of each rigid pressure strip is in contact with the coal sample;

[0008] The detection end of each rigid pressure strip is in contact with the normal hydraulic transmission shaft and the lateral hydraulic transmission shaft;

[0009] The outer sides of the left and right clamping plates of the rigid pressure strip clamp are provided with a rigid pressure strip clamp fixing shaft;

[0010] The coal sample is fixed by a coal sample side clamp and a coal sample rear baffle. The outer side of the coal sample side clamp is in contact with the hydraulic transmission shaft pressure plate. The outer side of the hydraulic transmission shaft pressure plate is equipped with a lateral hydraulic transmission shaft. The outer side of the coal sample rear baffle is equipped with a rear baffle fixing shaft.

[0011] The method for conducting a test using a non-uniformly distributed load loading test device based on elastic-plastic partitioning of a bearing coal pillar includes the following test steps:

[0012] Step 1: Determine the elastoplastic stress partition form of the coal sample and the stress distribution form of the applied load;

[0013] Step 2: adjusting the height of each rigid layering strip according to the elastoplastic stress partitioning form of the coal sample, selecting rigid layering strips with different stiffness according to the stress distribution form, and arranging and setting each rigid layering strip according to the sequence of stiffness distribution;

[0014] Step 3: Select rigid layering strips with different rigidity coefficients according to the rigidity distribution, and arrange the rigid layering strips in the sequence of the rigidity distribution;

[0015] Step 4: Determine the axial deformation size of the same specification coal samples in the elastic deformation stage, plastic deformation stage, and crack development stage through preliminary experiments, and adjust the height and arrangement position of each rigid layering strip according to the deformation size of each stage, and control the loading equipment to divide the coal samples according to the elastic-plastic stress after pressurization;

[0016] Step 5: Use the sorted rigid beading strips to bear the normal load, and determine the normal load value applied by the normal hydraulic transmission shaft at the detection end of each rigid beading strip;

[0017] Step 6: Use the coal sample clamp to fix the coal sample, apply lateral load to the left and right sides of the coal sample, and when the predetermined pressure level is reached, fix or remove the rear baffle, observe the crack development and coal dust outflow during the coal sample destruction process from the front end of the coal sample, and simulate the pressure and destruction of the real tunnel bearing coal pillar;

[0018] Step 7: After arranging the rigid pressure strips of different heights and rigidities, fix them by using a rigid pressure strip clamp, and place the fixed rigid pressure strips on the upper side of the coal sample through the rigid pressure strip clamp fixing axis;

[0019] Step 8: Control the loading equipment to perform the axial loading test and record the test data.

[0020] The specific method for adjusting the height of each rigid layering strip in step 2 is:

[0021] Calculate the height arrangement sequence of rigid layering strips:

[0022] Define the length of the long side of the rigid layering section as y, and the length of the wide side as x;

[0023] The definition of mechanical test is that the fracture partition width of the coal sample specimen is amm, the plastic partition width is bmm, the elastic partition width is cmm, and the number of rigid pressure strips arranged in each partition is n1, n2, and n3 respectively;

[0024] The parameters for obtaining the corresponding coal sample deformation are: the deformation from the initial state to the end of the elastic deformation stage is dmm, the deformation in the plastic deformation stage is emm, and the deformation in the pre-peak failure stage is fmm;

[0025] The calculation formulas for the number of rigid layering strips arranged in each partition are:

[0026]

[0027] The calculation formulas for the height difference of the rigid layering strips in each partition are:

[0028]

[0029] The height of the first rigid layering strip arranged in the elastic partition is defined as z1, and the heights of subsequent rigid layering strips are defined as z1+h1, z1+2h1, ..., z1+d by analogy;

[0030] Then the height of the first rigid layering strip arranged in the plastic zone is z1+d+h2, and the heights of subsequent rigid layering strips are z1+d+2h2, z1+d+3h2, ..., z1+d+e;

[0031] Then the height of the first rigid layering strip arranged in the elastic partition is z1+d+e+h3, and the heights of subsequent rigid layering strips are z1+d+e+2h3, z1+d+e+3h3, …, z1+d+e+f.

[0032] The specific method for selecting rigid layering strips with different stiffness coefficients in step 3 is:

[0033] Calculate the stiffness of the rigid layer:

[0034] Determine the distribution form of the load on the coal sample and treat the distribution form as a discrete load. The expression is:

[0035] σ=F(x);

[0036] The loads of each discrete point are σ1, σ2, σ3, …, σn in sequence;

[0037] Then, the stiffness distribution sequence of the rigid layering strips for loading is determined according to the distribution form of the load, where the relationship between the rigid layering strips and the load borne is:

[0038]

[0039] where k1, k2, k3, ..., k n are the stiffness coefficients of each rigid layering strip, and satisfy:

[0040] σ1:σ2:σ3:…:σ n =k1:k2:k3:…:k n .

[0041] The specific method for determining the normal load value applied to the normal hydraulic transmission shaft in step 5 is: the calculation formula of the normal load value is:

[0042]

[0043] The normal input load value of the testing machine is obtained by calculation and the specimen is preloaded.

[0044] The beneficial effects of the present invention compared with the prior art are as follows: the non-uniform load loading test scheme provided by the present invention realizes the elastic-plastic partitioning of coal samples by arranging rigid pressure strips of different heights in sequence, and the rigid pressure strips of different stiffness are subjected to different forces under the same deformation, thereby realizing the non-uniform load application. The provided test device has the advantages of simple structure, convenient operation, and easy processing, and effectively solves the problem of the destruction of the elastic-plastic partitioned coal pillar under the action of non-uniform load, so that the load loading test effect is more in line with the actual situation on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present invention will be further described below in conjunction with the accompanying drawings:

[0046] Figure 1 The relationship diagram between the tunnel surrounding rock partition and the total stress-strain curve adopted by the present invention;

[0047] Figure 2 It is a schematic diagram of stress partitioning under three typical coal pillar loads of the present invention;

[0048] Figure 3 The schematic diagram of the rigid layering arrangement for realizing elastic-plastic partitioning under three typical coal pillar loads of the present invention;

[0049] Figure 4 The front view and side view of the front and rear side clamps of the rigid pressure strip clamp of the present invention;

[0050] Figure 5 It is a front view and a top view of the left and right side clamps of the rigid pressure strip clamp of the present invention;

[0051] Figure 6 The front view and top view of the assembled rigid beading fixture of the present invention (without the rigid beading);

[0052] Figure 7 The front view and top view of the assembled rigid beading fixture of the present invention (when the rigid beading has been placed);

[0053] Figure 8 It is a schematic diagram of the coal sample fixture of the present invention in a loading state;

[0054] Fig. 9 It is a structural schematic diagram of the coal sample specimen loading test device of the present invention;

[0055] Fig.10 It is a statistical diagram of the discretization of the load distribution of the coal sample of the present invention;

[0056] In the figure: 1 is a rigid pressure strip, 2 is the front and rear side clamps of the rigid pressure strip clamp, 3 is a bolt mouth, 4 is the left and right side clamps of the rigid pressure strip clamp, 5 is a bolt, 6 is a coal sample, 7 is a coal sample side clamp, 8 is a coal sample rear baffle, 9 is a rear baffle fixing shaft, 10 is a lateral hydraulic transmission shaft, 11 is a hydraulic transmission shaft pressure plate, 12 is a rigid pressure strip clamp fixing shaft, and 13 is a normal hydraulic transmission shaft. DETAILED DESCRIPTION

[0057] like Figures 1 to 10 As shown, the present invention provides a non-uniform load loading test device based on the elastic-plastic partition of the bearing coal pillar, comprising a plurality of rigid pressure strips 1, each rigid pressure strip 1 is arranged according to the elastic-plastic stress partition form of the coal sample 6, and the arranged rigid pressure strips 1 are fixed by the front and rear side clamps 2 of the rigid pressure strip clamp and the left and right side clamps 4 of the rigid pressure strip clamp through bolts 5;

[0058] The sensing end of each rigid layering strip 1 is in contact with the coal sample 6;

[0059] The detection end of each rigid pressure strip 1 is in contact with the normal hydraulic transmission shaft 13 and the lateral hydraulic transmission shaft 10;

[0060] A rigid beading clamp fixing shaft 12 is installed on the outer sides of the left and right side clamps 4 of the rigid beading clamp;

[0061] The coal sample 6 is fixed by a coal sample side clamp 7 and a coal sample rear baffle 8. The outer side of the coal sample side clamp 7 is in contact with a hydraulic transmission shaft pressure plate 11. A lateral hydraulic transmission shaft 10 is installed on the outer side of the hydraulic transmission shaft pressure plate 11. The outer side of the coal sample rear baffle 8 is installed with a rear baffle fixing shaft 9.

[0062] Based on the test device, the present invention also provides a non-uniform load loading test method based on elastic-plastic partitioning of the bearing coal pillar, which specifically includes the following test steps:

[0063] Step 1: Refer to the corresponding relationship between the surrounding rock partition of the tunnel and the total stress-strain curve of the rock (see Figure 1 ), according to the mechanical properties of the surrounding rock, the tunnel surrounding rock is divided into four states: loose zone, fracture zone, plastic zone and elastic zone, thereby determining the elastic-plastic stress zoning form of the test coal sample and the stress distribution form of the applied load (see Figure 2 );

[0064] Step 2: Adjust the height of each rigid layering strip according to the elastoplastic stress partitioning form of the test coal sample, select rigid layering strips with different stiffness according to the stress distribution form, and sort the rigid layering strips according to the stiffness distribution sequence (see Figure 3 );

[0065] Step 3: Select rigid strips with different stiffness coefficients according to the stiffness distribution, and sort the rigid strips according to the stiffness distribution sequence (see Figure 3 );

[0066] Step 4: Determine the axial deformation of the same specification test coal sample when it enters the elastic deformation stage, plastic deformation stage and crack development stage through preliminary experiments. According to the deformation size of each stage, adjust the height and arrangement position of the rigid layering strips, so as to achieve the elastic-plastic stress zoning of the coal and rock samples after the loading equipment is pressurized;

[0067] Step 5: Determine the normal load value applied by the loading device on the upper end of all rigid beadings based on the normal load borne by each rigid beading after sorting. Rigid beadings of different stiffness are subjected to different forces under the same deformation, so the normal load applied by the loading device is converted into a normal non-uniform load on the specimen through each rigid beading;

[0068] Step 6: Fix the test coal sample with the coal sample fixture. The left and right sides can be loaded laterally to reach the predetermined horizontal pressure. The rear baffle can be fixed or removed according to the experimental requirements. There is no baffle restriction on the front side (the side of the bearing coal pillar facing the air), so the crack development and coal dust outflow during the coal sample destruction process can be observed, simulating the pressure and destruction of the bearing coal pillar in the real tunnel (see Figure 8 );

[0069] Step 7: Arrange the rigid beading strips of different heights and stiffnesses and fix them with the rigid beading strip clamp, and fix the rigid beading strip clamp to the upper end of the test coal sample based on the fixed axis (see Figures 4 to 7 );

[0070] Step 8: Perform an axial loading test (see Fig. 9 ).

[0071] The calculation process involved in the above test steps is as follows:

[0072] Take the stress partition mechanical test under the first type of typical coal pillar load as an example (see Figure 2 , Figure 3 ).

[0073] (1) Calculation of the height arrangement sequence of rigid layering strips:

[0074] Assume that the length of the long side of the rigid layering section is y, and the length of the wide side is x. Assume that the mechanical test uses a coal sample specimen of 300mm×100mm×100mm (length×width×height), the width of the fracture partition is amm, the width of the plastic partition is bmm, the width of the elastic partition is cmm, the original rock stress partition is not considered, and the number of rigid layerings arranged in each partition is n1, n2, and n3 respectively. The corresponding coal sample deformation parameters obtained from the preliminary experiment are as follows: the deformation from the initial state to the end of the elastic deformation stage is dmm, the deformation in the plastic deformation stage is emm, and the deformation in the pre-peak failure stage is fmm. The calculation formula for the number of rigid layerings arranged in each partition is as follows:

[0075]

[0076] The height differences of the rigid layering strips in each partition are:

[0077]

[0078] Assume that the height of the first rigid layering strip in the elastic partition arrangement is z1, and the subsequent ones are z1+h1, z1+2h1, …, z1+d;

[0079] Then the height of the first rigid layering strip in the plastic zoning arrangement is z1+d+h2, and the subsequent ones are z1+d+2h2, z1+d+3h2, ..., z1+d+e;

[0080] The height of the first rigid layering strip in the elastic partition arrangement is z1+d+e+h3, and the subsequent ones are z1+d+e+2h3, z1+d+e+3h3, …, z1+d+e+f.

[0081] (2) Calculation of rigid layering stiffness:

[0082] Determine the load distribution form of the test coal sample and approximate it as a discrete load (see Fig.10 ), the expression is: σ=F(x) (x is a positive integer), and the loads of each discrete point are σ1, σ2, σ3, …, σn.

[0083] The stiffness distribution sequence of the rigid layering strips used for loading is determined according to the distribution form of the load. The relationship between the rigid layering strips and the load they bear is:

[0084]

[0085] where k1, k2, k3, ..., k n are the stiffness coefficients of each rigid layering strip, and satisfy:

[0086] σ1:σ2:σ3:…:σ n =k1:k2:k3:…:k n .

[0087] The above calculations can be used to determine the arrangement sequence of the rigid layering strips, including the high and low arrangement of the rigid layering strips and the arrangement of the stiffness coefficients.

[0088] (3) Determine the normal preload of the testing machine. The calculation formula is:

[0089]

[0090] In this way, the normal input load of the testing machine can be determined and the specimen preloading can be achieved.

[0091] In order to prevent the rigid beading from yielding during the loading process, the present invention selects the rigid beading, the compressive strength of the rigid beading shall not be less than twice the load required to be borne; the roughness of the rigid beading shall not be greater than Ra0.40, and the dimensional error shall not be greater than 0.5%; at the same time, the surface of the rigid beading used needs to be polished to ensure that the contact surfaces are relatively smooth; lubricating oil needs to be applied between the rigid beadings and between the rigid beadings and the rigid beading fixtures to reduce the error effect of friction on the experiment.

[0092] The present invention can further improve the practicability and accuracy of the test: by simulating the elastic-plastic zoning behavior of the actual bearing coal pillar under non-uniformly distributed loads, the test method can provide test data that is closer to the actual mining conditions, thereby improving the practicability and accuracy of indoor tests; the test can deepen the understanding of the coal pillar failure mechanism: the test method can help researchers to more deeply understand the failure mechanism of the bearing coal pillar under different load conditions, especially the mechanical behavior during the formation and development of the elastic-plastic zoning; and according to the test results, the design parameters and support measures of the bearing coal pillar can be optimized, the stability and bearing capacity of the coal pillar can be improved, and the safety accidents in coal mining can be reduced; by conducting experimental research indoors, the setting and mining process of the bearing coal pillar can be optimized, the resource recovery rate can be improved, and the waste of resources can be reduced. In addition, the stability and damage risk of the bearing coal pillar can be predicted before actual application, avoiding economic losses caused by coal pillar damage in actual mining, which is helpful to develop a more effective coal pillar stability assessment method, provide a scientific basis for mine safety, and reduce the incidence of mine accidents.

[0093] 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 by 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 non-uniform load loading test device and method based on elastic-plastic partitioning of a bearing coal pillar, characterized in that: It comprises a plurality of rigid pressure strips (1), each rigid pressure strip (1) is arranged according to the elastic-plastic stress partitioning form of the coal sample (6), and the arranged rigid pressure strips (1) are fixed by front and rear side clamps (2) of the rigid pressure strip clamp and left and right side clamps (4) of the rigid pressure strip clamp via bolts (5); The sensing end of each rigid pressure strip (1) is in contact with the coal sample (6); The detection end of each rigid pressure strip (1) is in contact with the normal hydraulic transmission shaft (13) and the lateral hydraulic transmission shaft (10); A rigid beading clamp fixing shaft (12) is installed on the outer sides of the left and right side clamps (4) of the rigid beading clamp; The coal sample (6) is fixed by a coal sample side clamp (7) and a coal sample rear baffle (8); the outer side of the coal sample side clamp (7) is in contact with a hydraulic transmission shaft pressure plate (11); a lateral hydraulic transmission shaft (10) is installed on the outer side of the hydraulic transmission shaft pressure plate (11); and a rear baffle fixing shaft (9) is installed on the outer side of the coal sample rear baffle (8).

2. The method for conducting a test using the non-uniformly distributed load loading test device based on elastic-plastic partitioning of a bearing coal pillar according to claim 1, characterized in that: The test steps include the following: Step 1: determine the elastoplastic stress partition form of the coal sample (6) and the stress distribution form of the applied load; Step 2: adjusting the height of each rigid layering strip (1) according to the elastoplastic stress partitioning form of the coal sample (6), selecting rigid layering strips (1) of different stiffness according to the stress distribution form, and arranging each rigid layering strip (1) according to the sequence of stiffness distribution; Step 3: Selecting rigid layering strips (1) with different rigidity coefficients according to the rigidity distribution, and arranging the rigid layering strips (1) according to the sequence of the rigidity distribution; Step 4: Determine the axial deformation size of the coal sample (6) of the same specification when it enters the elastic deformation stage, the plastic deformation stage, and the crack development stage through preliminary experiments, and adjust the height and arrangement position of each rigid layering strip (1) according to the deformation size of each stage, and control the loading device to divide the coal sample (6) into zones according to the elastic-plastic stress after pressurization; Step 5: Use the sorted rigid pressure strips (1) to bear the normal load, and determine the normal load value applied by the normal hydraulic transmission shaft (13) at the detection end of each rigid pressure strip (1); Step 6: Use a coal sample clamp to fix the coal sample (6), apply lateral loads to the left and right sides of the coal sample (6), and when a predetermined pressure level is reached, fix or remove the rear baffle, observe the crack development and coal dust outflow during the coal sample destruction process from the front end of the coal sample (6), and simulate the pressure and destruction of the real tunnel bearing coal pillar; Step 7: After arranging the rigid pressure strips (1) of different heights and rigidities, fix them by means of a rigid pressure strip clamp, and place the fixed rigid pressure strips (1) on the upper side of the coal sample (6) through the rigid pressure strip clamp fixing shaft (12); Step 8: Control the loading equipment to perform the axial loading test and record the test data.

3. The method for conducting a test using the non-uniformly distributed load loading test device based on elastic-plastic partitioning of a bearing coal pillar according to claim 2, characterized in that: The specific method for adjusting the height of each rigid layering strip in step 2 is: Calculate the height arrangement sequence of rigid layering strips: Define the length of the long side of the rigid layering section as y, and the length of the wide side as x; Definition: The fracture partition width of the coal sample used in the mechanical test is a mm, the plastic partition width is b mm, the elastic partition width is c mm, and the number of rigid pressure strips (1) arranged in each partition is n1, n2, and n3 respectively; The parameters for obtaining the corresponding coal sample deformation are: the deformation from the initial state to the end of the elastic deformation stage is d mm, the deformation in the plastic deformation stage is e mm, and the deformation in the pre-peak failure stage is f mm; The calculation formulas for the number of rigid layering strips (1) arranged in each partition are: The calculation formulas for the height difference of the rigid layering strips (1) in each partition are: The height of the first rigid layering strip (1) arranged in the elastic partition is defined as z1, and the heights of subsequent rigid layering strips (1) are defined as z1+h1, z1+2h1, ..., z1+d by analogy; Then the height of the first rigid layering strip (1) arranged in the plastic partition is z1+d+h2, and the heights of the subsequent rigid layering strips (1) are z1+d+2h2, z1+d+3h2, ..., z1+d+e by analogy; Then the height of the first rigid layering strip (1) arranged in the elastic partition is z1+d+e+h3, and the heights of subsequent rigid layering strips (1) are z1+d+e+2h3, z1+d+e+3h3, ..., z1+d+e+f.

4. The method for conducting a test using the non-uniformly distributed load loading test device based on elastic-plastic partitioning of a bearing coal pillar according to claim 3, characterized in that: The specific method for selecting rigid layering strips with different stiffness coefficients in step 3 is: Calculate the stiffness of the rigid layer: Determine the distribution form of the load on the coal sample (6) and treat the distribution form as a discrete load. The expression is: σ=F(x); The loads of each discrete point are σ1, σ2, σ3, …, σn in sequence; Then, the stiffness distribution sequence of the loading rigid layering strip (1) is determined according to the distribution form of the load, wherein the relationship between the rigid layering strip (1) and the load borne is: where k1, k2, k3, ..., k n are the stiffness coefficients of each rigid layering strip (1) and satisfy:

5. The method for conducting a test using the non-uniformly distributed load loading test device based on elastic-plastic partitioning of a bearing coal pillar according to claim 4, characterized in that: The specific method for determining the normal load value applied to the normal hydraulic transmission shaft in step 5 is: the calculation formula of the normal load value is: The normal input load value of the testing machine is obtained by calculation and the specimen is preloaded.

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