Coal-rock burst tendency evaluation method based on energy dissipation and transformation mechanism

Abstract

The present disclosure proposes a coal rock impact tendency evaluation method based on the energy dissipation and transformation mechanism, comprising: performing a triaxial compression test on a first coal rock sample to obtain a peak stress, performing a triaxial cyclic loading and unloading test on a second coal rock sample according to the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve, solving the coal rock energy balance differential equation based on the conservation relationship of external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve, and determining the target parameters in the coal rock energy balance differential equation that affect the degree of coal rock damage, determining an evaluation index based on the target parameters, calculating the index value of the evaluation index based on the experimental data of the triaxial cyclic loading and unloading test, and determining the coal rock impact tendency evaluation result corresponding to the index value based on pre-set evaluation rules, thereby achieving the effect of accurately evaluating the coal rock impact.

Description

Technical Field

[0001] The present disclosure relates to the field of geological early warning technology, and in particular to a method for evaluating coal rock impact tendency based on energy dissipation and conversion mechanism. Background Art

[0002] Rock burst is a common coal-rock dynamic hazard in underground coal mines. It typically manifests as the sudden and violent release of a large amount of elastic energy accumulated within the open rock mass, destroying the rock mass while throwing a large amount of rock debris into the mining space, accompanied by explosions and shock waves. With increasing mining depth and the increasingly complex coal mine production environment, the threat of rock burst is increasing, becoming a major problem that plagues safe and efficient coal mine production. Therefore, there is an urgent need to develop an efficient and accurate method for evaluating coal-rock burst propensity, which is of great significance for early warning of rock burst hazards in underground coal mines.

[0003] In related technologies, energy-based evaluation indices for coal rock impact propensity include the elastic energy index (WET), the impact energy index (KE), the modified impact energy index (WCP'), the impact energy velocity index (WST), the effective elastic energy release rate index (KET), the residual elastic energy index (CEF), the peak strain energy storage index (WETp), and so on. However, these indices are all based on the energy density relationships at various analysis angles as reflected by the uniaxial stress-strain curve. In other words, they are based solely on analysis of coal rock experimental results and lack a systematic study of the relationship between internal energy dissipation and conversion in coal rock. Therefore, while there are many existing coal rock impact propensity evaluation indices, they lack sufficient theoretical basis. It is necessary to propose a coal rock impact propensity evaluation method that can fully reflect the energy characteristics of coal rock. Summary of the Invention

[0004] This application proposes a method and device for evaluating coal rock impact tendency based on energy dissipation and conversion mechanism, aiming to solve one of the technical problems in related technologies at least to a certain extent.

[0005] The first embodiment of the present application proposes a method for evaluating the impact tendency of coal rock based on the energy dissipation and transformation mechanism, including: performing a triaxial compression test on a first coal rock sample to obtain a peak stress; performing a triaxial cyclic loading and unloading test on a second coal rock sample according to the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve; solving the coal rock energy balance differential equation based on the conservation relationship of external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve; determining the target parameters that affect the degree of coal rock damage in the coal rock energy balance differential equation, and determining an evaluation index based on the target parameters; calculating the index value of the evaluation index based on the experimental data of the triaxial cyclic loading and unloading test; and determining the coal rock impact tendency evaluation result corresponding to the index value based on a pre-set evaluation rule.

[0006] The second embodiment of the present application proposes a coal rock impact tendency evaluation device based on the energy dissipation and transformation mechanism, including: a first experimental module, used to perform a triaxial compression test on a first coal rock sample to obtain a peak stress; a second experimental module, used to perform a triaxial cyclic loading and unloading test on a second coal rock sample according to the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve; a solution module, used to solve the coal rock energy balance differential equation based on the conservation relationship of external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve; a determination module, used to determine the target parameters affecting the degree of coal rock damage in the coal rock energy balance differential equation, and determine the evaluation index according to the target parameters; a calculation module, used to calculate the index value of the evaluation index based on the experimental data of the triaxial cyclic loading and unloading experiment; and an evaluation module, used to determine the coal rock impact tendency evaluation result corresponding to the index value based on a pre-set evaluation rule.

[0007] The third aspect embodiment of the present application proposes an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the coal rock impact tendency evaluation method based on energy dissipation and conversion mechanism of the embodiment of the present application.

[0008] The fourth aspect of the present application proposes a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable the computer to execute the coal rock impact tendency evaluation method based on energy dissipation and conversion mechanism disclosed in the embodiment of the present application.

[0009] In this embodiment, a triaxial compression test is performed on the first coal rock sample to obtain the peak stress, and a triaxial cyclic loading and unloading test is performed on the second coal rock sample based on the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve. Based on the conservation relationship of external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve, the coal rock energy balance differential equation is solved, and the target parameters affecting the degree of coal rock damage in the coal rock energy balance differential equation are determined. The evaluation index is determined based on the target parameters, and the index value of the evaluation index is calculated based on the experimental data of the triaxial cyclic loading and unloading test. Based on the pre-set evaluation rules, the coal rock impact tendency evaluation result corresponding to the index value is determined. Energy constraints can be imposed on the entire stress-strain process of the coal rock and the entire process of coal rock damage and destruction, the differential equation of the internal energy relationship of the coal rock is derived, and the target parameters in the differential equation are proposed as the dynamic destruction criterion of the coal rock, thereby achieving the effect of accurately evaluating the coal rock impact.

[0010] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0012] Figure 1 This is a flow chart of a method for evaluating coal rock impact tendency based on energy dissipation and conversion mechanism proposed in one embodiment of the present disclosure;

[0013] Figure 2 is a schematic diagram of a triaxial cyclic loading and unloading stress-strain curve proposed in an embodiment of the present disclosure;

[0014] Figure 3 is a schematic diagram of a first fitting curve proposed in an embodiment of the present disclosure;

[0015] Figure 4 is a schematic diagram of a second fitting curve proposed in an embodiment of the present disclosure;

[0016] Figure 5 is a schematic diagram of a coal rock impact tendency evaluation device based on energy dissipation proposed in another embodiment of the present disclosure;

[0017] Figure 6 A block diagram of an exemplary computer device suitable for implementing embodiments of the present application is shown. DETAILED DESCRIPTION

[0018] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present disclosure and are not to be construed as limiting the present disclosure. On the contrary, the embodiments of the present disclosure include all variations, modifications, and equivalents that fall within the spirit and scope of the appended claims.

[0019] Among them, it should be noted that the executor of the coal-rock impact tendency evaluation method based on energy dissipation and conversion mechanism of this embodiment can be a coal-rock impact tendency evaluation device based on energy dissipation, which can be implemented by software and / or hardware. The device can be configured in an electronic device, and the electronic device may include but is not limited to a terminal, a server, etc.

[0020] Figure 1 This is a flow chart of a method for evaluating coal rock impact tendency based on energy dissipation and conversion mechanism according to an embodiment of the present disclosure. Figure 1 As shown, the method includes:

[0021] S101: Perform a triaxial compression test on the first coal rock sample to obtain peak stress.

[0022] The coal rock samples used in the experiment in this embodiment can be referred to as the first coal rock sample and the second coal rock sample (also referred to as coal rock specimens). Specifically, in practical applications, according to the standard "Standard Test Methods for Engineering Rocks" (GB / T 50266-2013), rock cores collected at the engineering site can be processed into standard cylindrical specimens with a size of φ50×100 mm to prepare two groups of coal rock samples, a and b, corresponding to the first coal rock sample and the second coal rock sample of this embodiment, respectively.

[0023] In this embodiment, the confining pressure value can be set according to the surrounding rock stress conditions at the engineering site, and the experimental system can be controlled to perform a conventional triaxial compression test on the first coal rock sample (group a coal rock sample) to obtain the peak stress of the coal rock.

[0024] S102: performing a triaxial cyclic loading and unloading test on the second coal rock sample according to the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve.

[0025] Furthermore, a triaxial cyclic loading and unloading test is performed on the second coal rock sample according to the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve.

[0026] In some embodiments, during the operation of conducting triaxial cyclic loading and unloading experiments on the second coal rock sample (group B coal rock sample), based on the peak stress obtained from the group A test, loading and unloading can be performed about 9 times before the stress peak, and the load level can be gradually increased from 0.1 times the peak strength to 0.9 times the peak strength. In the post-peak softening stage, loading and unloading can be performed as much as possible to ensure that at least 10 loading and unloading cycles are performed throughout the process to obtain the triaxial cyclic loading and unloading stress-strain curve.

[0027] S103: Solve the energy balance differential equation of coal rock based on the conservation relationship between external force work, elastic energy increment, and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve.

[0028] Figure 2 is a schematic diagram of the triaxial cyclic loading and unloading stress-strain curve proposed in the embodiment of the present disclosure, such as Figure 2 As shown in the figure, during the loading process, the experimental system inputs energy to the second coal rock sample through external force work, and the integral area OAC of the loading curve is the energy density of the energy input by the external force work; during the unloading process, the elastic energy accumulated inside the coal rock is released, so the integral area ABC of the unloading curve represents the energy density of the elastic energy; and the integral area OAB between the loading curve and the unloading curve represents the dissipated energy density.

[0029] The embodiment of the present disclosure can solve the energy balance differential equation of coal rock based on the conservation relationship of external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve.

[0030] In some embodiments, the differential equations of the work done by the external force, the elastic energy increment, and the damage dissipation energy can be determined. The differential equation of the work done by the external force can be expressed as δw, the differential equation of the elastic energy increment can be expressed as de, and the differential equation of the damage dissipation energy can be expressed as δa.

[0031] Furthermore, based on the law of conservation of energy and differential equations, the energy balance differential equation of coal rock is solved. That is, under conventional triaxial loading conditions, the energy balance differential equation of coal rock is established and solved according to the law of conservation of energy. The initial energy balance differential equation can be expressed as:

[0032] δw=de+δa (1)

[0033] Where w represents the work done by the external force on the system (i.e., the work done by the external force), e represents the elastic energy of the system, a represents the damage dissipation energy, and δ and d represent the differential signs of the process quantity and state quantity, respectively.

[0034] In the operation of determining the differential expressions of the external force work, elastic energy increment, and damage dissipation energy, this embodiment first determines the coal rock damage expression:

[0035]

[0036] Among them, D represents the amount of coal rock damage, which is dimensionless; E represents the damaged elastic modulus of coal rock, that is, the elastic modulus of the coal rock material after damage, and the unit is MPa; E0 represents the initial elastic modulus of coal rock, that is, the elastic modulus of coal rock in the non-destructive state, which can be determined according to the type of coal rock, and the unit is MPa.

[0037] Furthermore, under conventional triaxial cyclic loading and unloading, assuming that the circumferential expansion of coal rock material is affected by the combined effects of confining pressure and damage, the relationship between the circumferential strain and axial strain of coal rock can be expressed as:

[0038] ε2=ε3=(μ-Kσ3D)ε1 (3)

[0039] Among them, ε2 and ε3 represent the circumferential strains of two axes, ε1 represents the axial strain of one axis, and the circumferential strains of the two axes in the conventional triaxial loading and unloading test of this embodiment are the same; μ represents the Poisson's ratio of coal rock; K represents the material parameter of coal rock, the unit is MPa-1, which can be determined according to the type of coal rock, and is 0.2 in this embodiment; σ3 represents the confining pressure, the unit is MPa, which is equal to the directional stress of the third axis.

[0040] Furthermore, assuming that the nonlinear characteristics of coal rock are related to the three-dimensional stress state, the expression of the damage elastic modulus of coal rock is derived as follows:

[0041] E=E0[1-exp(-0.02σ M )] (4)

[0042] Among them, σ M represents the mean stress, σ1, σ2, and σ3 represent the stresses in the three directions of the triaxial line.

[0043] Furthermore, under conventional triaxial loading, the coal rock stress expression is determined based on the coal rock damage expression (Equation 2) and the coal rock damage elastic modulus expression (Equation 4):

[0044]

[0045] Among them, ε 1e represents the axial elastic strain.

[0046] Furthermore, according to the coal rock damage expression (2), the coal rock damage elastic modulus expression (4), the relationship between the circumferential strain and the axial strain (3), and the coal rock stress expression (5), the differential expressions of the external force work, the elastic energy increment, and the damage dissipation energy are determined respectively, namely: δw, de, and δa.

[0047] Among them, the differential formula δw of the work done by the external force can be expressed as:

[0048] δw=σ1dε1-σ2dε2-σ3dε3=E0[1-exp(-0.02σ M )](1-D)ε 1e dε1-2σ3(μ-Kσ3D)dε1 (6)

[0049] The differential formula of elastic energy increment de can be expressed as:

[0050]

[0051] The differential formula of damage dissipation energy δa is expressed as:

[0052] δa=YdD (8)

[0053] Where Y represents the damage energy consumption rate. The physical meaning of the damage energy consumption rate Y is the energy consumed when the damage variable increases by one unit value. The unit is MJ·m -3 .

[0054] Furthermore, (6), (7), and (7) are substituted into formula (1) to solve the final coal-rock energy balance differential equation, which can be expressed as:

[0055]

[0056] Among them, in the differential formula de of the elastic energy increment in formula (7), the first term on the right side of the equal sign indicates that the elastic energy increases with the increase of axial elastic strain; the second term on the right side of the equal sign indicates that as the coal rock damage increases, the elastic energy gradually decreases and is released to the outside; the part before the damage increment in the second term on the right side of the equal sign can be expressed as:

[0057]

[0058] Among them, T e It represents the elastic energy released per unit damage, that is, the elastic energy released from the unit damage generated inside the coal rock.

[0059] Substituting (10) into (9), another expression of the coal-rock energy balance differential equation can be obtained:

[0060]

[0061] S104: Determine target parameters that affect the degree of coal rock damage in the coal rock energy balance differential equation, and determine evaluation indicators based on the target parameters, wherein the target parameters include damage energy consumption rate and elastic energy released per unit damage.

[0062] Among them, the parameters that affect the degree of coal rock damage in the coal rock energy balance differential equation can be called target parameters, and the target parameters can be one parameter or multiple parameters, without limitation.

[0063] Some embodiments, as shown in formula (11), can express the differential form of the internal energy relationship of coal rock under peak stress. When the axial stress reaches the peak stress, the coal rock is about to be destroyed, and the coal rock destruction form at this time is determined by Y and T e That is, the target parameters affecting the degree of coal rock damage in this embodiment may include the damage energy consumption rate Y and the unit damage release elastic energy T e .

[0064] From formula (11), we can see that when YT e >0, the energy dissipated by unit damage is greater than or equal to the elastic energy released by unit damage, and the coal rock failure is static evolution; when YT e When <0, the energy dissipated by unit damage is less than the elastic energy released by unit damage, which is equivalent to the elastic energy accumulated inside the coal rock cannot be completely consumed by damage. The excess elastic energy will be converted into kinetic energy to destroy the coal rock. At this time, the coal rock destruction evolves dynamically.

[0065] Therefore, the evaluation index of this embodiment can be expressed as:

[0066] P=YTe (12)

[0067] Wherein, P represents the evaluation index. When P>=0, the coal-rock state is static destruction; when P<0, the coal-rock state is dynamic destruction.

[0068] S105: Calculating the index value of the evaluation index according to the experimental data of the triaxial cyclic loading and unloading test.

[0069] Specifically, the actual value of the damage energy consumption rate Y and the elastic energy released per unit damage T can be calculated based on the experimental data. e The actual value of is substituted into formula (12) to calculate the index value of the evaluation index P.

[0070] In some embodiments, in the process of calculating the value of the damage energy consumption rate Y, this embodiment can use the coal rock damage expression (Formula 2) to calculate the coal rock damage amount D at each unloading point based on experimental data, and combine Figure 2 Calculate the energy density of dissipated energy corresponding to each unloading point, that is, damage dissipated energy a, where the coal rock damage amount D and damage dissipated energy a satisfy a linear relationship; further, as Figure 3 As shown, in this embodiment, the coal rock damage amount D and the damage dissipation energy a at each unloading point can be plotted as a scatter plot, and linear fitting can be performed to obtain a first fitting curve; further, according to formula (8) or Figure 3 In this embodiment, the slope of the first fitting curve can be used as the value of the damage energy consumption rate Y.

[0071] In other embodiments, the elastic energy T released by unit damage inside the coal rock is e It can be calculated based on experimental data. Among them, the variable T e There is only one unknown in the equation, namely the axial elastic strain ε when the stress reaches its peak value. 1e , ε 1e It can be obtained according to the linear evolution law of elastic strain. The linear evolution law of elastic strain can be expressed as follows: before the stress peak in the process of uniaxial or triaxial loading of coal rock, the axial elastic strain and the hoop elastic strain increase linearly with the axial strain and the hoop strain respectively.

[0072] Among them, in the process of calculating the value of the elastic energy released per unit damage, this embodiment can first obtain the axial strain corresponding to each unloading point when the unloading curve decreases to 0 based on experimental data and cyclic loading and unloading stress-strain curve, thereby obtaining the axial elastic strain corresponding to the unloading point.

[0073] Furthermore, if Figure 4 As shown, the axial elastic strain and axial strain of each unloading point are linearly fitted to obtain the second fitting curve. The linear relationship between the axial elastic strain and the axial strain can be expressed as:

[0074] ε 1e =Hε1 (13)

[0075] Where H is the linear coefficient, which is obtained by data fitting and is dimensionless.

[0076] Furthermore, based on the second fitting curve (i.e., Equation 13), the axial elastic strain value corresponding to the axial strain value at the peak stress is calculated. In other words, the axial strain at the peak stress moment is substituted into Equation (13) to obtain the axial elastic strain at the peak moment. Furthermore, the axial elastic strain is substituted into Equation (10) to calculate the elastic energy released per unit damage T e The numerical value of .

[0077] S106: Based on pre-set evaluation rules, determine the coal rock impact tendency evaluation result corresponding to the index value.

[0078] The evaluation rules may be as shown in Table 1, for example:

[0079] Table 1

[0080]

[0081] After calculating the value of the coal rock dynamic failure evaluation index P, this embodiment can compare the value of the evaluation index P with the evaluation rules. When P>=0, the coal rock has no impact tendency; when -2<=P<0, the coal rock has a weak impact tendency; and when P<-2, the coal rock has a strong impact tendency. Thus, the impact tendency of the coal rock can be evaluated.

[0082] Based on the law of conservation of energy, the present invention establishes and solves the energy balance differential equation of coal rock, imposes energy constraints on the entire stress-strain process of coal rock and the entire process of coal rock damage and destruction, and derives the differential form of the internal energy relationship of coal rock under peak stress. The damage energy consumption rate is obtained by fitting experimental data, and the axial elastic strain corresponding to the stress peak is obtained according to the linear evolution law of elastic strain, thereby proposing a dynamic failure criterion for coal rock and realizing the evaluation of coal rock impact tendency. It solves the problem that it is difficult to unload coal rock when it reaches peak strength and thus it is impossible to measure the axial elastic strain. The impact tendency of coal rock is determined by calculating the mathematical relationship between the energy dissipated by unit damage generated in the coal rock and the elastic energy released by unit damage. It fully reflects the energy characteristics of coal rock and provides a new evaluation method for determining the impact tendency of coal rock.

[0083] In this embodiment, a triaxial compression test is performed on a first coal rock sample to obtain a peak stress, and a triaxial cyclic loading and unloading test is performed on a second coal rock sample based on the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve. Based on the conservation relationship of external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve, the coal rock energy balance differential equation is solved, and the target parameters affecting the degree of coal rock damage in the coal rock energy balance differential equation are determined. The evaluation index is determined based on the target parameters, and the index value of the evaluation index is calculated based on the experimental data of the triaxial cyclic loading and unloading test. Based on pre-set evaluation rules, the coal rock impact tendency evaluation result corresponding to the index value is determined. Energy constraints can be imposed on the entire stress-strain process of the coal rock and the entire process of coal rock damage and destruction, the differential equation of the internal energy relationship of the coal rock is derived, and the target parameters in the differential equation are proposed as the dynamic failure criterion of the coal rock, thereby achieving the effect of accurately evaluating the coal rock impact.

[0084] Figure 5 is a schematic diagram of a coal rock impact tendency evaluation device based on energy dissipation and conversion mechanism according to another embodiment of the present disclosure, such as Figure 5 As shown, the coal-rock impact tendency evaluation device 50 based on energy dissipation includes:

[0085] The first experimental module 501 is used to perform a triaxial compression test on a first coal rock sample to obtain a peak stress;

[0086] The second experimental module 502 is used to perform a triaxial cyclic loading and unloading experiment on the second coal rock sample according to the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve;

[0087] A solution module 503 is used to solve the coal rock energy balance differential equation based on the conservation relationship of external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve;

[0088] Determination module 504, for determining target parameters affecting the degree of coal-rock damage in the coal-rock energy balance differential equation, and determining evaluation indicators based on the target parameters;

[0089] A calculation module 505 is used to calculate the index value of the evaluation index based on the experimental data of the triaxial cyclic loading and unloading experiment; and

[0090] The evaluation module 506 is used to determine the coal rock burst tendency evaluation result corresponding to the indicator value based on a pre-set evaluation rule.

[0091] In some embodiments, the solution module 503 is specifically configured to:

[0092] Determine the differential equations for the work done by the external force, the elastic energy increment, and the damage dissipation energy; and

[0093] Based on the law of conservation of energy and differential formula, the coal rock energy balance differential equation is solved, where the coal rock energy balance differential equation is expressed as:

[0094]

[0095] Where, E0 represents the initial elastic modulus of coal rock; represents the average stress of the three directions σ1, σ2, and σ3, where σ3 is equal to the confining pressure; ε 1e represents axial elastic strain; k represents coal rock material parameters; D represents coal rock damage; ε1 represents axial strain; μ represents coal rock Poisson's ratio; Y represents damage energy consumption rate; Indicates the elastic energy released per unit damage.

[0096] In some embodiments, the differential equation δw for the work done by the external force is expressed as:

[0097] δw=σ1dε1-σ2dε2-σ3dε3=E0[1-exp(-0.02σ M )](1-D)ε 1e dε1-2σ3(μ-Kσ3D)dε1

[0098] Wherein, ε2 and ε3 represent hoop strain, and ε2=ε3=(μ-Kσ3D)ε1.

[0099] In some embodiments, the differential formula de of the elastic energy increment is expressed as:

[0100]

[0101] In some embodiments, the differential formula δa of the damage dissipation energy is expressed as: δa=YdD.

[0102] In some embodiments, the solution module 503 is specifically configured to:

[0103] Determine the coal rock damage expression Where D represents the amount of coal rock damage, and E represents the elastic modulus of coal rock damage;

[0104] Determine the elastic modulus of coal rock damage E=E0[1-exp(-0.02σ M )];

[0105] Determine the relationship between the circumferential strain and axial strain of coal rock during triaxial cyclic loading and unloading tests ε2=ε3=(μ-Kσ3D)ε1;

[0106] According to the coal rock damage expression and the coal rock damage elastic modulus expression, the coal rock stress expression is determined

[0107]

[0108] According to the coal rock damage expression, coal rock damage elastic modulus expression, the relationship between circumferential strain and axial strain, and coal rock stress expression, the differential expressions of external force work, elastic energy increment, and damage dissipation energy are determined respectively.

[0109] In some embodiments, the evaluation index is expressed as: P = YT e , where P represents the evaluation index.

[0110] In some embodiments, the calculation module 505 is specifically used to: calculate the values ​​of the damage energy consumption rate and the elastic energy released per unit damage according to the experimental data; and calculate the index value of the evaluation index according to the numerical values.

[0111] In some embodiments, the calculation module 505 is specifically used to: linearly fit the coal rock damage amount and damage dissipation energy at each unloading point according to experimental data to obtain a first fitting curve; and use the slope of the first fitting curve as the value of the damage energy dissipation rate.

[0112] In some embodiments, the calculation module 505 is specifically configured to: perform a linear fit on the axial elastic strain and the axial strain at each unloading point based on the experimental data to obtain a second fitting curve;

[0113] Calculating the axial elastic strain value corresponding to the axial strain value at the peak stress based on the second fitting curve; and

[0114] According to the axial elastic strain value, the value of elastic energy released per unit damage is determined.

[0115] In this embodiment, a triaxial compression test is performed on a first coal rock sample to obtain a peak stress, and a triaxial cyclic loading and unloading test is performed on a second coal rock sample based on the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve. Based on the conservation relationship of external force work, elastic energy increment, and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve, the coal rock energy balance differential equation is solved, and target parameters affecting the degree of coal rock damage in the coal rock energy balance differential equation are determined. Evaluation indicators are determined based on the target parameters, wherein the target parameters include damage energy dissipation rate and elastic energy released per unit damage. The index value of the evaluation index is calculated based on the experimental data of the triaxial cyclic loading and unloading test, and the coal rock impact tendency evaluation result corresponding to the index value is determined based on a pre-set evaluation rule. Energy constraints can be imposed on the entire stress-strain process of the coal rock and the entire process of coal rock damage and destruction, and the differential equation of the internal energy relationship of the coal rock is derived. The damage energy dissipation rate and elastic energy released per unit damage in the differential equation are proposed as dynamic failure criteria for the coal rock, thereby achieving the effect of accurately evaluating the coal rock impact.

[0116] According to an embodiment of the present disclosure, the present disclosure also provides an electronic device, a readable storage medium, and a computer program product.

[0117] In order to implement the above embodiments, the present application also proposes a computer program product. When the instruction processor in the computer program product is executed, it executes the coal rock impact tendency evaluation method based on energy dissipation and conversion mechanism proposed in the above embodiments of the present application.

[0118] Figure 6 A block diagram of an exemplary computer device suitable for implementing embodiments of the present application is shown. Figure 6 The computer device 12 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0119] like Figure 6 As shown, computer device 12 is implemented as a general-purpose computing device. Components of computer device 12 may include, but are not limited to, one or more processors or processing units 16, system memory 28, and a bus 18 that connects various system components (including system memory 28 and processing unit 16).

[0120] Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus architectures. Examples of such architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MAC) bus, the Enhanced ISA bus, the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnection (PCI) bus.

[0121] The computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0122] The memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 34 may be configured to read and write non-removable, non-volatile magnetic media ( Figure 6 Not shown, often called a "hard drive").

[0123] although Figure 6 Not shown, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a Compact Disc Read Only Memory (hereinafter referred to as: CD-ROM), a Digital Video Disc Read Only Memory (hereinafter referred to as: DVD-ROM), or other optical media) may be provided. In these cases, each drive can be connected to the bus 18 via one or more data medium interfaces. The memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the various embodiments of the present application.

[0124] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in memory 28. Such program modules 42 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data, each of which, or some combination thereof, may include an implementation of a network environment. Program modules 42 generally implement the functions and / or methods of the embodiments described herein.

[0125] The computer device 12 can also communicate with one or more external devices 14 (e.g., a keyboard, pointing device, display 24, etc.), one or more devices that enable a user to interact with the computer device 12, and / or any device that enables the computer device 12 to communicate with one or more other computing devices (e.g., a network card, a modem, etc.). This communication can occur via an input / output (I / O) interface 22. Furthermore, the computer device 12 can communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network such as the Internet) via a network adapter 20. As shown, the network adapter 20 communicates with the other modules of the computer device 12 via a bus 18. It should be understood that, although not shown, other hardware and / or software modules can be used in conjunction with the computer device 12, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0126] The processing unit 16 executes various functional applications and data processing by running programs stored in the system memory 28, such as implementing the coal rock impact tendency evaluation method based on energy dissipation and conversion mechanism mentioned in the above embodiment.

[0127] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0128] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

[0129] It should be noted that, in the description of this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0130] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0131] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0132] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0133] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0134] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0135] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0136] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for evaluating coal rock impact tendency based on energy dissipation and conversion mechanism, characterized in that: The method comprises: A triaxial compression test is performed on the first coal rock sample to obtain the peak stress; performing a triaxial cyclic loading and unloading test on the second coal rock sample according to the peak stress to obtain a triaxial cyclic loading and unloading stress-strain curve; Based on the conservation relationship between the external force work, elastic energy increment and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve, the energy balance differential equation of coal rock is solved; Determine the target parameters that affect the degree of coal rock damage in the coal rock energy balance differential equation, and determine the evaluation index based on the target parameters, the target parameters include the damage energy consumption rate Y and the unit damage release elastic energy T e ; Calculating the index value of the evaluation index based on the experimental data of the triaxial cyclic loading and unloading test; and Based on a pre-set evaluation rule, determining a coal rock burst tendency evaluation result corresponding to the index value; The method solves the coal rock energy balance differential equation based on the conservation relationship of external force work, elastic energy increment, and damage dissipation energy represented by the triaxial cyclic loading and unloading stress-strain curve, including: Determining the differential formulas of the external force work, elastic energy increment, and damage dissipation energy respectively; and Based on the law of conservation of energy and the differential formula, the coal-rock energy balance differential equation is solved, wherein the coal-rock energy balance differential equation is expressed as: Where, E0 represents the initial elastic modulus of coal rock; represents the average stress of the three directions σ1, σ2, and σ3, where σ3 is equal to the confining pressure; ε 1e represents axial elastic strain; K represents coal rock material parameters; D represents coal rock damage; ε1 represents axial strain; μ represents coal rock Poisson's ratio; Y represents damage energy consumption rate; Indicates the elastic energy released per unit damage.

2. The method according to claim 1, wherein The differential formula δw of the work done by the external force is expressed as: δw=σ1dε1-σ2dε2-σ3dε3=E0[1-exp(-0.02σ M )](1-D)e 1e dε1-2σ3(μ-Kσ3D)dε1 Where w represents the work done by the external force, ε2 and ε3 represent the hoop strain, and ε2 = ε3 = (μ - Kσ3D)ε1.

3. The method according to claim 1, wherein The differential formula de of the elastic energy increment is expressed as: Here, e represents elastic energy.

4. The method according to claim 1, wherein The differential formula δa of the damage dissipation energy is expressed as: δa=YdD, where a represents the damage dissipation energy.

5. The method according to claim 1, wherein The differential formulas for respectively determining the external force work, elastic energy increment, and damage dissipation energy include: Determine the coal rock damage expression Where D represents the amount of coal rock damage, and E represents the elastic modulus of coal rock damage; Determine the coal rock damage elastic modulus expression E=E0[1-exp(-0.02σ M )]; Determine the relationship between the circumferential strain and axial strain of coal rock during triaxial cyclic loading and unloading tests ε2=ε3=(μ-Kσ3D)ε1; According to the coal rock damage expression and the coal rock damage elastic modulus expression, the coal rock stress expression is determined. According to the coal rock damage expression, coal rock damage elastic modulus expression, circumferential strain and axial strain relationship expression, and coal rock stress expression, the differential expressions of the external force work, elastic energy increment, and damage dissipation energy are determined respectively.

6. The method according to claim 1, wherein in, The target parameters include the damage energy consumption rate Y and the unit damage release elastic energy T e ; The evaluation index is expressed as: P = YT e .

7. The method according to claim 6, wherein The calculating of the index value of the evaluation index based on the experimental data of the triaxial cyclic loading and unloading test includes: According to the experimental data, the damage energy consumption rate Y and the unit damage release elastic energy T are calculated respectively. e the value of ; and Calculate the index value of the evaluation index based on the numerical value.

8. The method according to claim 7, wherein Calculating the values ​​of the damage energy consumption rate and the elastic energy released per unit damage based on the experimental data includes: According to the experimental data, linearly fitting the coal rock damage amount and damage dissipation energy at each unloading point to obtain a first fitting curve; and The slope of the first fitting curve is used as the value of the damage energy consumption rate.

9. The method according to claim 7, wherein Calculating the values ​​of the damage energy consumption rate and the elastic energy released per unit damage based on the experimental data includes: According to the experimental data, the axial elastic strain and the axial strain at each unloading point are linearly fitted to obtain a second fitting curve; Calculating the axial elastic strain value corresponding to the axial strain value at the peak stress based on the second fitting curve; and The value of the elastic energy released per unit damage is determined according to the axial elastic strain value.

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