A two-dimensional simulation method and system for dynamic evolution of goaf stiffness

Abstract

The present invention discloses a two-dimensional simulation method and system for the dynamic evolution of the goaf stiffness. The method includes: determining the working face length parameter, setting the goaf filling interval distance based on the working face length parameter, and deriving the stress change rules of different goafs according to the goaf filling interval distance; determining the stress change characteristics of the pressurized area, decompression area, and stable pressure area of different goafs according to the stress change rules; constructing a goaf model based on the stress change characteristics of the pressurized area, decompression area, and stable pressure area of different goafs, and simulating the dynamic parameters of the abutment pressure growth rate of the goaf through the goaf model and the mechanical properties of the caved gangue. By determining the pressure action characteristics of each area of the goaf, the change relationship between the abutment pressure growth rate and the stiffness of the goaf is simulated, and then the influence of the stiffness on the force borne by the overlying strata is simulated, thereby providing reference conditions for the length setting of the goaf and improving the convenience.

Description

Technical Field

[0001] The present invention relates to the technical field of data simulation, and particularly to a two-dimensional simulation method and system for the dynamic evolution of the goaf stiffness. Background Art

[0002] At present, there is a stiffness relationship between the support and the surrounding rock in the stope system in both the vertical direction and the advancing direction of the working face, which is of great significance to the stability of the coal wall and the surrounding rock. As the working face advances, the distribution of the abutment pressure before and after the coal mining face is a dynamic evolution process. Among them, the gob gangue plays a supporting role in the overlying strata of the stope, and to a certain extent, it can relieve the load borne by the solid coal and the hydraulic support in the working face. From the perspective of the advancing direction of the working face, the weight of the overlying strata is jointly borne by the support system composed of "coal wall - support - gob". In fact, the weight of the overlying strata is mainly borne by the solid coal in the working face. If the supporting effect of the gob on the overlying strata is ignored, it will lead to an excessive load borne by the coal body and the hydraulic support, and a high abutment pressure in front of the working face.

[0003] As the working face continuously advances, the caved gangue in the gob repeats the cycle process of "accumulation - compaction - bearing pressure". Its deformation compaction and bearing characteristics are a complex rock mechanics problem. The caved gangue in the gob can relieve the pressure on the coal wall and the hydraulic support in the working face to a certain extent, and has an important impact on the stress distribution and evolution law of the stope surrounding rock and the coal wall in the working face. Therefore, the supporting effect of the gob stiffness on the overlying strata cannot be ignored. When conducting numerical simulation research on the stability of the coal wall, the influence of the gob stiffness must be considered. Summary of the Invention

[0004] Aiming at the problems shown above, the present invention provides a two-dimensional simulation method for the dynamic evolution of the goaf stiffness to simulate the influence of the goaf material stiffness on the bearing force of the overlying strata, thereby providing reference conditions for setting the length of the goaf to solve the problem that the supporting effect of the goaf height on the overlying strata is not considered in the background art, resulting in poor stability of the goaf and reduced practicability and reliability.

[0005] A two-dimensional simulation method for the dynamic evolution of the goaf stiffness includes the following steps:

[0006] Determine the working face length parameter, set the gob filling interval distance based on the working face length parameter, and deduce the stress change law of different goafs according to the gob filling interval distance;

[0007] Determine the stress change characteristics of the pressure increasing area, pressure decreasing area and pressure stabilizing area of different goafs according to the stress change law;

[0008] Construct a goaf model based on the stress change characteristics of the pressure-increasing area, pressure-reducing area, and pressure-stabilizing area in different goafs, and simulate the dynamic parameters of the abutment pressure growth rate in the goaf through the goaf model and the mechanical properties of the caved gangue;

[0009] Evolve the dynamic parameters of the abutment pressure growth rate in the goaf into stiffness dynamic parameters.

[0010] Preferably, to determine the working face length parameter, set the goaf filling interval distance based on the working face length parameter, and deduce the stress change law of different goafs according to the goaf filling interval distance, including:

[0011] Determine the design parameters of the working face, determine the working face length parameter according to the design parameters, and determine the advancing distance based on the working face length;

[0012] Determine the buffer effect of the goaf according to the advancing distance and the theoretical stress load of the working face, and determine the set area of a single goaf according to the buffer effect;

[0013] Set the goaf filling interval distance based on the set area of a single goaf and the working face length parameter;

[0014] Determine the sampling point coordinates of each sampling area according to the goaf filling interval distance and the preset sampling point distribution law, set stress sensors at the sampling point coordinates to detect the stress change situation of each goaf, and deduce the stress change law according to the stress change situation.

[0015] Preferably, to determine the stress change characteristics of the pressure-increasing area, pressure-reducing area, and pressure-stabilizing area in different goafs according to the stress change law, including:

[0016] Construct stress change curves of different goafs according to the stress change law, and determine the change trend of the stress coefficient peak according to the stress change curves;

[0017] Divide the stress change curve into a pressure-increasing curve, a pressure-reducing curve, and a pressure-stabilizing curve according to the change trend of the stress coefficient peak;

[0018] Obtain the corresponding spatio-temporal domain parameters of the pressure-increasing curve, the pressure-reducing curve, and the pressure-stabilizing curve respectively, and determine the pressure-increasing area, the pressure-reducing area, and the pressure-stabilizing area of different goafs according to the spatio-temporal domain corresponding parameters;

[0019] Determine the stress transition attribute according to the stress change parameters of the pressure-increasing area, pressure-reducing area, and pressure-stabilizing area of different goafs respectively, and determine the stress change characteristics of the pressure-increasing area, pressure-reducing area, and pressure-stabilizing area of different goafs according to the stress transition attribute.

[0020] Preferably, a goaf model is constructed based on the stress change characteristics of the pressure increasing area, pressure decreasing area, and pressure stabilizing area in different goafs, and the dynamic parameters of the abutment pressure growth rate in the goaf are simulated through the goaf model and the mechanical properties of the caved gangue, including:

[0021] Construct a goaf model based on the stress change characteristics of the pressure increasing area, pressure decreasing area, and pressure stabilizing area in different goafs and the overlying strata covering density volume parameters;

[0022] Determine the variation function of the stiffness of the caved gangue with respect to distance according to the mechanical properties of the caved gangue, and determine the respective stiffness variation intervals in the pressure increasing area, pressure decreasing area, and pressure stabilizing area of the goaf according to the variation function;

[0023] Simulate the variation curve of the abutment pressure growth rate under the pressure of the overlying strata through the goaf model according to the stiffness variation interval;

[0024] Determine the dynamic parameters of the abutment pressure growth rate in the goaf according to the variation curve of the abutment pressure growth rate and the theoretical value of the abutment pressure.

[0025] Preferably, evolving the dynamic parameters of the abutment pressure growth rate in the goaf into stiffness dynamic parameters includes:

[0026] Determine the conversion definition between the abutment pressure growth rate parameter and the stiffness parameter, and determine the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter according to the conversion definition;

[0027] Establish a mathematical model for the change of the abutment pressure in the goaf, and determine the law of the change of the abutment pressure in the goaf with time through the mathematical model;

[0028] Perform numerical simulation according to the law of the change of the abutment pressure in the goaf with time through the mathematical model based on the dynamic parameters of the abutment pressure growth rate in the goaf;

[0029] Obtain the simulated dynamic numerical value of the abutment pressure growth according to the simulation result, convert the simulated dynamic numerical value of the abutment pressure growth into the simulated dynamic numerical value of the stiffness according to the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter, and determine the stiffness dynamic parameter according to the simulated dynamic numerical value of the stiffness.

[0030] A two-dimensional simulation system for the dynamic evolution of the goaf stiffness, the system includes:

[0031] A derivation module, used to determine the working face length parameter, set the goaf filling interval distance based on the working face length parameter, and derive the stress change law of different goafs according to the goaf filling interval distance;

[0032] A determination module, used to determine the stress change characteristics of the pressure increasing area, pressure decreasing area, and pressure stabilizing area of different goafs according to the stress change law;

[0033] A simulation module, configured to construct a goaf model based on the stress change characteristics of the pressurized area, depressurized area, and pressure-stabilized area of different goafs, and simulate the dynamic parameters of the abutment pressure growth rate in the goaf through the goaf model and the mechanical properties of the caved gangue;

[0034] An evolution module, configured to evolve the dynamic parameters of the abutment pressure growth rate in the goaf into stiffness dynamic parameters.

[0035] Preferably, the derivation module includes:

[0036] A first determination sub-module, configured to determine the design parameters of the working face, determine the working face length parameter according to the design parameters, and generate a determined advancing distance based on the working face length;

[0037] A second determination sub-module, configured to determine the buffering effect of the goaf according to the advancing distance and the theoretical stress load of the working face, and determine the set area of a single goaf according to the buffering effect;

[0038] A setting sub-module, configured to set the goaf filling interval distance based on the set area of a single goaf and the working face length parameter;

[0039] A derivation sub-module, configured to determine the sampling point coordinates of each sampling area according to the goaf filling interval distance and the preset sampling point distribution rule, set stress sensors at the sampling point coordinates to detect the stress change situation of each goaf, and derive the stress change rule according to the stress change situation.

[0040] Preferably, the determination module includes:

[0041] A third determination sub-module, configured to construct a stress change curve graph of different goafs according to the stress change rule, and determine the peak change trend of the stress coefficient according to the stress change curve graph;

[0042] A division sub-module, configured to divide the stress change curve into a pressurization curve, a depressurization curve, and a pressure-stabilization curve according to the peak change trend of the stress coefficient;

[0043] A fourth determination sub-module, configured to respectively obtain the spatio-temporal domain corresponding parameters of the pressurization curve, the depressurization curve, and the pressure-stabilization curve, and determine the pressurized area, depressurized area, and pressure-stabilized area of different goafs according to the spatio-temporal domain corresponding parameters;

[0044] A fifth determination sub-module, configured to determine the stress transition attribute according to the stress change parameters of the pressurized area, depressurized area, and pressure-stabilized area of different goafs respectively, and determine the stress change characteristics of the pressurized area, depressurized area, and pressure-stabilized area of different goafs according to the stress transition attribute.

[0045] Preferably, the simulation module includes:

[0046] A construction sub-module, configured to construct a goaf model based on the stress change characteristics of the pressure-increasing area, pressure-reducing area, and pressure-stabilizing area of different goafs and the overburden layer covering density volume parameters;

[0047] A sixth determination sub-module, configured to determine the variation function of the caving gangue stiffness with respect to distance according to the mechanical properties of the caving gangue, and determine the respective stiffness variation intervals within the pressure-increasing area, pressure-reducing area, and pressure-stabilizing area of the goaf according to the variation function;

[0048] A simulation sub-module, configured to simulate the variation curve of the abutment pressure growth rate under the pressure of the overburden layer through the goaf model according to the stiffness variation interval;

[0049] A seventh determination sub-module, configured to determine the dynamic parameters of the abutment pressure growth rate in the goaf according to the variation curve of the abutment pressure growth rate and the theoretical value of the abutment pressure.

[0050] Preferably, the evolution module includes:

[0051] An eighth determination sub-module, configured to determine the conversion definition between the abutment pressure growth rate parameter and the stiffness parameter, and determine the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter according to the conversion definition;

[0052] A ninth determination sub-module, configured to establish a mathematical model for the change of the abutment pressure in the goaf, and determine the law of the change of the abutment pressure in the goaf with time through the mathematical model;

[0053] A numerical simulation sub-module, configured to perform numerical simulation according to the dynamic parameters of the abutment pressure growth rate in the goaf through the mathematical model according to the law of the change of the abutment pressure in the goaf with time;

[0054] A conversion sub-module, configured to obtain the simulated dynamic value of the abutment pressure growth according to the simulation result, convert the simulated dynamic value of the abutment pressure growth into the simulated dynamic value of the stiffness according to the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter, and determine the dynamic stiffness parameter according to the simulated dynamic value of the stiffness.

[0055] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the written specification, claims, and drawings.

[0056] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0057] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention.

[0058] Figure 1 It is a flowchart of a two-dimensional simulation method for the dynamic evolution of the goaf stiffness provided by the present invention;

[0059] Figure 2 It is another flowchart of a two-dimensional simulation method for the dynamic evolution of the goaf stiffness provided by the present invention;

[0060] Figure 3 It is a schematic structural diagram of a two-dimensional simulation system for the dynamic evolution of the goaf stiffness provided by the present invention;

[0061] Figure 4 It is a schematic structural diagram of a derivation module in a two-dimensional simulation system for the dynamic evolution of the goaf stiffness provided by the present invention. Detailed implementation manners

[0062] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0063] Currently, there is a stiffness relationship between the support and the surrounding rock in the stope system in both the vertical direction and the advancing direction of the working face, which is of great significance for the stability of the coal wall and the surrounding rock. As the working face advances, the distribution of the abutment pressure before and after the coal mining face is a dynamic evolution process. Among them, the gangue in the goaf has a supporting effect on the overlying strata of the stope, and to a certain extent, it can relieve the loads borne by the solid coal in the working face and the hydraulic support. From the perspective of the advancing direction of the working face, the weight of the overlying strata is jointly borne by the support system composed of "coal wall in the working face - support - goaf". In fact, the weight of the overlying strata is mainly borne by the solid coal in the working face. If the supporting effect of the goaf on the overlying strata is ignored, it will lead to an excessive load borne by the coal body and the hydraulic support, and a high abutment pressure in front of the working face.

[0064] As the working face continuously advances, the caved gangue in the goaf repeats the cycle of "accumulation - compaction - pressure bearing". Its deformation compaction and bearing characteristics are complex rock mechanics problems. The caved gangue in the goaf can relieve the pressure on the coal wall and hydraulic supports of the working face to a certain extent, and has an important impact on the stress distribution and evolution law of the surrounding rock of the stope and the coal wall of the working face. Therefore, the stiffness of the goaf cannot be ignored in its bearing effect on the overlying strata. When conducting numerical simulation studies on the stability of the coal wall, the influence of the goaf stiffness must be considered. To solve the above problems, this embodiment discloses a two-dimensional simulation method for the dynamic evolution of the goaf stiffness.

[0065] A two-dimensional simulation method for the dynamic evolution of the goaf stiffness, as Figure 1 shown, includes the following steps:

[0066] Step S101: Determine the working face length parameter, set the goaf filling interval distance based on the working face length parameter, and deduce the stress change law of different goafs according to the goaf filling interval distance;

[0067] Step S102: Determine the stress change characteristics of the pressure increase area, pressure reduction area, and pressure stabilization area of different goafs according to the stress change law;

[0068] Step S103: Build a goaf model based on the stress change characteristics of the pressure increase area, pressure reduction area, and pressure stabilization area of different goafs, and simulate the dynamic parameters of the bearing pressure growth rate of the goaf through the goaf model and the mechanical properties of the caved gangue;

[0069] Step S104: Evolve the dynamic parameters of the bearing pressure growth rate of the goaf into stiffness dynamic parameters.

[0070] The working principle of the above technical solution is: Determine the working face length parameter, set the goaf filling interval distance based on the working face length parameter, and deduce the stress change law of different goafs according to the goaf filling interval distance; Determine the stress change characteristics of the pressure increase area, pressure reduction area, and pressure stabilization area of different goafs according to the stress change law; Build a goaf model based on the stress change characteristics of the pressure increase area, pressure reduction area, and pressure stabilization area of different goafs, and simulate the dynamic parameters of the bearing pressure growth rate of the goaf through the goaf model and the mechanical properties of the caved gangue.

[0071] The beneficial effects of the above technical solution are: By determining the pressure action characteristics of each area of the goaf, the change relationship between the bearing pressure growth rate and the stiffness of the goaf is simulated, and then the influence of the stiffness on the bearing force of the overlying strata is simulated, providing a reference condition for the length setting of the goaf, improving convenience, and solving the problem in the background technology that the bearing effect of the goaf height on the overlying strata is not considered, resulting in poor stability of the goaf, and reducing the practicality and reliability.

[0072] In one embodiment, as Figure 2 shown, determining the working face length parameter, setting the gob filling interval distance based on the working face length parameter, and deriving the stress change law of different gob areas according to the gob filling interval distance, including:

[0073] Step S201: Determine the design parameters of the working face, determine the working face length parameter according to the design parameters, and generate the advancing distance based on the determined working face length;

[0074] Step S202: Determine the buffering effect of the gob area according to the advancing distance and the theoretical stress load of the working face, and determine the setting area of a single gob area according to the buffering effect;

[0075] Step S203: Set the gob filling interval distance based on the setting area of a single gob area and the working face length parameter;

[0076] Step S204: Determine the sampling point coordinates of each sampling area according to the gob filling interval distance and the preset sampling point distribution law, set stress sensors at the sampling point coordinates to detect the stress change of each gob area, and derive the stress change law according to the stress change situation.

[0077] The beneficial effects of the above technical solution are as follows: By determining the setting area of the gob area according to the buffering effect and then determining the gob filling interval distance, the buffering effect of the gob area can be ensured while maximizing the advancing effect of the working face, improving the practicability and reliability. Further, by determining the sampling point coordinates for data sampling and stress law derivation, the reliability and high quality of the collected data can be ensured, laying a foundation for subsequent work and further improving the practicability.

[0078] In one embodiment, determining the stress change characteristics of the pressurized area, depressurized area, and stable pressure area of different gob areas according to the stress change law, including:

[0079] Construct a stress change curve graph of different gob areas according to the stress change law, and determine the change trend of the stress coefficient peak value according to the stress change curve graph;

[0080] Divide the stress change curve into a pressurized curve, a depressurized curve, and a stable pressure curve according to the change trend of the stress coefficient peak value;

[0081] Respectively obtain the corresponding parameters of the time-space domain of the pressurized curve, depressurized curve, and stable pressure curve, and determine the pressurized area, depressurized area, and stable pressure area of different gob areas according to the corresponding parameters of the time-space domain;

[0082] Determine the stress transition attribute according to the stress change parameters of the pressurized area, depressurized area, and stable pressure area in different gob areas, and determine the stress change characteristics of the pressurized area, depressurized area, and stable pressure area in different gob areas according to the stress transition attribute.

[0083] The beneficial effects of the above technical solution are as follows: By determining the pressurized area, depressurized area, and stable pressure area in different gob areas according to the spatio-temporal domain correspondence effect, and then determining the pressure qualitative situation of the area, the pressure qualitative attributes of each area in different gob areas can be intuitively determined, and then the stress transition attribute can be quickly determined to determine the stress change characteristics, improving the practicability and stability.

[0084] In one embodiment, a gob area model is constructed based on the stress change characteristics of the pressurized area, depressurized area, and stable pressure area in different gob areas, and the dynamic parameters of the abutment pressure growth rate in the gob area are simulated through the gob area model and the mechanical properties of the caved gangue, including:

[0085] Construct a gob area model based on the stress change characteristics of the pressurized area, depressurized area, and stable pressure area in different gob areas and the overlying rock layer covering density volume parameters;

[0086] Determine the variation function of the caved gangue stiffness with respect to distance according to the mechanical properties of the caved gangue, and determine the respective stiffness transition intervals in the pressurized area, depressurized area, and stable pressure area in the gob area according to the variation function;

[0087] Simulate the variation curve of the abutment pressure growth rate under the pressure of the overlying rock layer through the gob area model according to the stiffness transition interval;

[0088] Determine the dynamic parameters of the abutment pressure growth rate in the gob area according to the variation curve of the abutment pressure growth rate and the theoretical value of the abutment pressure.

[0089] The beneficial effects of the above technical solution are as follows: By determining the respective stiffness transition intervals in the pressurized area, depressurized area, and stable pressure area in the gob area according to the variation function of the caved gangue stiffness with respect to distance, the stiffness change range can be accurately located based on the distance-stiffness change characteristics of the caved gangue, and then the stiffness transition interval can be calculated through the function, improving the data accuracy and objectivity.

[0090] In one embodiment, evolving the dynamic parameters of the abutment pressure growth rate in the gob area into stiffness dynamic parameters includes:

[0091] Determine the conversion definition between the abutment pressure growth rate parameter and the stiffness parameter, and determine the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter according to the conversion definition;

[0092] Establish a mathematical model of the abutment pressure change in the gob area, and determine the law of the abutment pressure change with time in the gob area through the mathematical model.

[0093] According to the law of the abutment pressure in the goaf changing with time, numerical simulation is carried out through a mathematical model based on the dynamic parameters of the abutment pressure growth rate in the goaf;

[0094] Obtain the simulated dynamic numerical value of the abutment pressure growth according to the simulation results, convert the simulated dynamic numerical value of the abutment pressure growth into the simulated dynamic numerical value of the stiffness according to the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter, and determine the dynamic stiffness parameter according to the simulated dynamic numerical value of the stiffness.

[0095] The beneficial effects of the above technical solution are as follows: It is possible to intuitively perform accurate numerical conversion through numerical simulation according to the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter, ensuring the reliability, objectivity and reference value of the data, laying a foundation for the subsequent work and improving the practicability.

[0096] In one embodiment, the mechanical properties of the caved gangue (goaf stiffness) behind the working face are usually set to a constant value in the final stage; however, in actual field situations, the mechanical properties of the caved gangue used in the goaf are a function of time and distance. Specifically, since the caved gangue will gradually be compacted by the bending and subsiding roof as time and the advancing distance increase. Therefore, when performing numerical simulation, the physical and mechanical properties of the caved gangue should change dynamically as the working face advances, that is, the farther away from the working face, the greater the stiffness of the caving, until after the working face advances a certain distance, the caved gangue at the far end reaches the ultimate strength, while the caved gangue near the working face always maintains a lower strength.

[0097] Under different advancing distances, the distribution characteristics of the abutment pressure in front of and behind the working face. When the goaf is not processed in the model, as the working face advances, the abutment pressure behind the working face is 0, the abutment pressure in front of the working face continuously increases, and the influence range of the abutment pressure continuously expands; when the goaf is processed, a complete pressure relief area and a pressure stabilization area appear behind the working face, and the abutment pressure in front of the working face does not always increase. In the case of not processing the goaf, the abutment pressure increase coefficient of the working face increases monotonically as the working face advances. After the model excavation is completed, the abutment pressure concentration coefficient reaches about 18; while after processing the goaf, the abutment pressure increase coefficient increases first and then stabilizes as the working face advances. After the model excavation is completed, the abutment pressure concentration coefficient reaches about 3. Therefore, in the stope system stiffness in the advancing direction of the working face, the goaf stiffness has a greater impact on the support of the overlying strata and can relieve the abutment pressure in front of the coal wall of the working face. In order to reasonably simulate the complete pressure increase area, pressure relief area and pressure stabilization area abutment pressure distribution law in front of and behind the working face, the influence of the goaf stiffness must be considered in the numerical model, otherwise it will cause too high abutment pressure in front of the working face and too large coal wall failure range, which is inconsistent with the actual field situation.

[0098] According to the dynamic evolution characteristics of the pressure relief area and the stable pressure area in the goaf during the advancement of the working face, a goaf model was constructed. The peak values of the stress concentration coefficient in front of the working face of the goaf 1 and 2 models both showed a changing pattern of first increasing and then stabilizing. When the cutting roadway of the working face was opened, the abutment pressure coefficients of the goaf 1 and 2 models were both about 1.4. As the working face advanced, a goaf was formed behind the working face. Since the stiffness of goaf 1 was relatively small, the growth rate of the abutment pressure in front of the working face of the goaf 1 model was relatively fast, while the growth of the abutment pressure in goaf 2 was slower. When the working face advanced about 80 m, the peak values of the abutment pressure concentration coefficients of the goaf 1 and 2 models both tended to be stable. At this time, it was considered that the model reached a stable state. The stress concentration coefficient of goaf 1 was stable at about 2.86, and the stress concentration coefficient of goaf 2 was stable at about 2.60.

[0099] When the abutment pressure in front of the working face reached stability, 150 m of the working face advancement was arbitrarily selected as the research object, and the distribution laws of the abutment pressure in front of and behind the working face were made. Compared with other numerical models that only simulated and studied the abutment pressure in front of the working face, this model correctly simulated the distribution characteristics of the abutment pressure in the goaf, that is, there were obvious pressure relief areas and stable pressure areas in the abutment pressure in the goaf. Since the material stiffness of goaf 1 was small and the bearing capacity was weak, in the pressure relief area of the goaf, the abutment pressure of the goaf 1 model was significantly less than that of goaf 2; in the stable pressure area, the abutment pressures of the goaf 1 and 2 models were basically equal. The abutment pressure in front of the working face could also be divided into the limit equilibrium area and the elastic area. Among them, the peak value of the abutment pressure concentration coefficient of the goaf 1 model was 2.87, and the distance from the working face was 8.42 m. The peak value of the abutment pressure concentration coefficient of the goaf 2 model was 2.60, and the distance from the working face was 7.57 m. Therefore, when the goaf had a large stiffness (especially the early stiffness of the goaf), it could bear more weight of the overlying strata, relieve the load borne by the solid coal in the working face, reduce the abutment pressure in front of the working face, shorten the distance from the peak value of the abutment pressure to the working face, and reduce the influence range of the abutment pressure.

[0100] In one embodiment, this embodiment also discloses a two-dimensional simulation system for the dynamic evolution of the goaf stiffness, as Figure 3 shown. This system includes:

[0101] A derivation module 301, which is used to determine the working face length parameter, set the goaf filling interval distance based on the working face length parameter, and derive the stress change laws of different goafs according to the goaf filling interval distance;

[0102] A determination module 302, which is used to determine the stress change characteristics of the pressure increase area, pressure relief area, and stable pressure area of different goafs according to the stress change laws;

[0103] The simulation module 303 is used to construct a goaf model based on the stress change characteristics of the pressurized area, depressurized area, and stable pressure area of different goafs, and simulate the dynamic parameters of the abutment pressure growth rate in the goaf through the goaf model and the mechanical properties of the caved gangue;

[0104] The evolution module 304 is used to evolve the dynamic parameters of the abutment pressure growth rate in the goaf into stiffness dynamic parameters.

[0105] The working principle and beneficial effects of the above technical solution have been described in the method embodiment and will not be elaborated here.

[0106] In one embodiment, as Figure 4 shown, the derivation module 301 includes:

[0107] The first determination sub-module 3011 is used to determine the design parameters of the working face, determine the working face length parameter according to the design parameters, and generate a determined advance distance based on the working face length;

[0108] The second determination sub-module 3012 is used to determine the buffering effect of the goaf according to the advance distance and the theoretical stress load of the working face, and determine the setting area of a single goaf according to the buffering effect;

[0109] The setting sub-module 3013 is used to set the goaf filling interval distance based on the setting area of a single goaf and the working face length parameter;

[0110] The derivation sub-module 3014 is used to determine the sampling point coordinates of each sampling area according to the goaf filling interval distance and the preset sampling point distribution law, set stress sensors at the sampling point coordinates to detect the stress change situation of each goaf, and derive the stress change law according to the stress change situation.

[0111] In one embodiment, the determination module includes:

[0112] The third determination sub-module is used to construct a stress change curve graph of different goafs according to the stress change law, and determine the peak change trend of the stress coefficient according to the stress change curve graph;

[0113] The division sub-module is used to divide the stress change curve into a pressurized curve, a depressurized curve, and a stable pressure curve according to the peak change trend of the stress coefficient;

[0114] The fourth determination sub-module is used to respectively obtain the spatio-temporal domain corresponding parameters of the pressurized curve, the depressurized curve, and the stable pressure curve, and determine the pressurized area, depressurized area, and stable pressure area of different goafs according to the spatio-temporal domain corresponding parameters;

[0115] A fifth determination sub-module, configured to determine a stress transition attribute according to the stress change parameters of the pressure-increasing area, pressure-decreasing area, and pressure-stabilizing area of different goafs, and determine the stress change characteristics of the pressure-increasing area, pressure-decreasing area, and pressure-stabilizing area of different goafs according to the stress transition attribute.

[0116] In one embodiment, the simulation module includes:

[0117] A construction sub-module, configured to construct a goaf model based on the stress change characteristics of the pressure-increasing area, pressure-decreasing area, and pressure-stabilizing area of different goafs and the overlying strata covering density volume parameters;

[0118] A sixth determination sub-module, configured to determine the variation function of the caving gangue stiffness with respect to distance according to the mechanical properties of the caving gangue, and determine the respective stiffness transition intervals in the pressure-increasing area, pressure-decreasing area, and pressure-stabilizing area of the goaf according to the variation function;

[0119] A simulation sub-module, configured to simulate the variation curve of the abutment pressure growth rate under the pressure of the overlying strata through the goaf model according to the stiffness transition interval;

[0120] A seventh determination sub-module, configured to determine the dynamic parameters of the abutment pressure growth rate of the goaf according to the variation curve of the abutment pressure growth rate and the theoretical value of the abutment pressure.

[0121] In one embodiment, the evolution module includes:

[0122] An eighth determination sub-module, configured to determine the conversion definition between the abutment pressure growth rate parameter and the stiffness parameter, and determine the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter according to the conversion definition;

[0123] A ninth determination sub-module, configured to establish a mathematical model for the change of the abutment pressure in the goaf, and determine the law of the change of the abutment pressure in the goaf with time through the mathematical model;

[0124] A numerical simulation sub-module, configured to perform numerical simulation according to the law of the change of the abutment pressure in the goaf with time through the mathematical model according to the dynamic parameters of the abutment pressure growth rate of the goaf;

[0125] A conversion sub-module, configured to obtain the simulated dynamic numerical value of the abutment pressure growth according to the simulation result, convert the simulated dynamic numerical value of the abutment pressure growth into the simulated dynamic numerical value of the stiffness according to the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter, and determine the dynamic stiffness parameter according to the simulated dynamic numerical value of the stiffness.

[0126] Those skilled in the art should understand that the first and second in the present invention refer to different application stages.

[0127] Other embodiments of the present disclosure will be readily apparent to those skilled in the art in view of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the following claims.

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

Claims

1. A two-dimensional simulation method for the dynamic evolution of the stiffness of a goaf, characterized in that, Including the following steps: Determine the working face length parameter, set the gob filling interval distance based on the working face length parameter, and deduce the stress change law of different gob areas according to the gob filling interval distance; Determine the stress change characteristics of the pressure increasing area, pressure decreasing area and pressure stabilizing area of different gob areas according to the stress change law; Construct a gob area model based on the stress change characteristics of the pressure increasing area, pressure decreasing area and pressure stabilizing area of different gob areas, and simulate the dynamic parameters of the abutment pressure growth rate in the gob area through the gob area model and the mechanical properties of the caved gangue; Evolve the dynamic parameters of the abutment pressure growth rate in the gob area into stiffness dynamic parameters; The constructing a gob area model based on the stress change characteristics of the pressure increasing area, pressure decreasing area and pressure stabilizing area of different gob areas, and simulating the dynamic parameters of the abutment pressure growth rate in the gob area through the gob area model and the mechanical properties of the caved gangue includes: Construct a gob area model based on the stress change characteristics of the pressure increasing area, pressure decreasing area and pressure stabilizing area of different gob areas and the overlying strata covering density volume parameter; Determine the variation function of the caved gangue stiffness with distance according to the mechanical properties of the caved gangue, and determine the respective stiffness variation intervals in the pressure increasing area, pressure decreasing area and pressure stabilizing area of the gob area according to the variation function; Simulate the variation curve of the abutment pressure growth rate under the pressure of the overlying strata through the gob area model according to the stiffness variation interval; Determine the dynamic parameters of the abutment pressure growth rate in the gob area according to the variation curve of the abutment pressure growth rate and the theoretical value of the abutment pressure; The evolving the dynamic parameters of the abutment pressure growth rate in the gob area into stiffness dynamic parameters includes: Determine the conversion definition between the abutment pressure growth rate parameter and the stiffness parameter, and determine the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter according to the conversion definition; Establish a mathematical model of the abutment pressure change in the gob area, and determine the law of the abutment pressure change with time in the gob area through the mathematical model; Conduct numerical simulation according to the dynamic parameters of the abutment pressure growth rate in the gob area through the mathematical model according to the law of the abutment pressure change with time in the gob area; Obtain the dynamic numerical value of the abutment pressure growth simulation according to the simulation result, convert the dynamic numerical value of the abutment pressure growth simulation into the dynamic numerical value of the stiffness simulation according to the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter, and determine the stiffness dynamic parameter according to the dynamic numerical value of the stiffness simulation; 2. The two-dimensional simulation method for dynamic evolution of goaf stiffness according to claim 1, wherein The determining the working face length parameter, setting the gob filling interval distance based on the working face length parameter, and deducing the stress change law of different gob areas includes: Determine the design parameters of the working face, determine the working face length parameter according to the design parameters, and determine the advancing distance based on the working face length; Determine the buffering effect of the gob area according to the advancing distance and the theoretical stress load of the working face, and determine the set area of a single gob area according to the buffering effect; Set the gob filling interval distance based on the set area of a single gob area and the working face length parameter; Determine the sampling point coordinates of each sampling area according to the gob filling interval distance and the preset sampling point distribution law, set stress sensors at the sampling point coordinates to detect the stress change situation of each gob, and deduce the stress change law according to the stress change situation.

3. The two-dimensional simulation method for dynamic evolution of goaf stiffness according to claim 1, characterized in that, The determination of the stress change characteristics of the pressurized area, depressurized area, and stable pressure area of different gobs according to the stress change law includes: Construct stress change curve graphs of different gobs according to the stress change law, and determine the change trend of the peak stress coefficient according to the stress change curve graphs; Divide the stress change curve into a pressurizing curve, a depressurizing curve, and a stable pressure curve according to the change trend of the peak stress coefficient; Obtain the corresponding spatio-temporal domain parameters of the pressurizing curve, depressurizing curve, and stable pressure curve respectively, and determine the pressurized area, depressurized area, and stable pressure area of different gobs according to the spatio-temporal domain corresponding parameters; Determine the stress transition attribute according to the stress change parameters of the pressurized area, depressurized area, and stable pressure area of different gobs, and determine the stress change characteristics of the pressurized area, depressurized area, and stable pressure area of different gobs according to the stress transition attribute.

4. A two-dimensional simulation system for the dynamic evolution of the stiffness of a gob area, characterized in that, The system includes: A derivation module for determining the working face length parameter, setting the gob filling interval distance based on the working face length parameter, and deducing the stress change law of different gobs according to the gob filling interval distance; A determination module for determining the stress change characteristics of the pressurized area, depressurized area, and stable pressure area of different gobs according to the stress change law; A simulation module for constructing a gob model based on the stress change characteristics of the pressurized area, depressurized area, and stable pressure area of different gobs, and simulating the dynamic parameters of the abutment pressure growth rate in the gob through the gob model and the mechanical properties of the caved gangue; An evolution module for evolving the dynamic parameters of the abutment pressure growth rate in the gob into stiffness dynamic parameters; The simulation module includes: A construction sub-module for constructing a gob model based on the stress change characteristics of the pressurized area, depressurized area, and stable pressure area of different gobs and the overlying strata covering density volume parameter; A sixth determination sub-module for determining the variation function of the caved gangue stiffness with distance according to the mechanical properties of the caved gangue, and determining the respective stiffness transition intervals in the pressurized area, depressurized area, and stable pressure area of the gob according to the variation function; A simulation sub-module for simulating the change curve of the abutment pressure growth rate under the pressure of the overlying strata through the gob model according to the stiffness transition interval; A seventh determination sub-module for determining the dynamic parameters of the abutment pressure growth rate in the gob according to the abutment pressure growth rate change curve and the theoretical value of the abutment pressure; The evolution module includes: An eighth determination sub-module for determining the conversion definition between the abutment pressure growth rate parameter and the stiffness parameter, and determining the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter according to the conversion definition; A ninth determination sub-module for establishing a mathematical model of the abutment pressure change in the gob, and determining the law of the abutment pressure change with time in the gob through the mathematical model; A numerical simulation sub-module for performing numerical simulation according to the law of the abutment pressure change with time in the gob through the mathematical model based on the dynamic parameters of the abutment pressure growth rate in the gob. A conversion sub-module for obtaining the simulated dynamic value of abutment pressure growth according to the simulation result, converting the simulated dynamic value of abutment pressure growth into the simulated dynamic value of stiffness according to the numerical conversion rule between the abutment pressure growth rate parameter and the stiffness parameter, and determining the dynamic stiffness parameter according to the simulated dynamic value of stiffness.

5. The goaf stiffness dynamic evolution two-dimensional simulation system according to claim 4, characterized in that The derivation module includes: A first determination sub-module for determining the design parameters of the working face, determining the working face length parameter according to the design parameters, and generating a determined advancing distance based on the working face length; A second determination sub-module for determining the buffering effect of the goaf according to the advancing distance and the theoretical stress load of the working face, and determining the set area of a single goaf according to the buffering effect; A setting sub-module for setting the goaf filling interval distance based on the set area of a single goaf and the working face length parameter; A derivation sub-module for determining the sampling point coordinates of each sampling area according to the goaf filling interval distance and the preset sampling point distribution rule, setting stress sensors at the sampling point coordinates to detect the stress change situation of each goaf, and deriving the stress change rule according to the stress change situation.

6. The goaf stiffness dynamic evolution two-dimensional simulation system according to claim 4, wherein The determination module includes: A third determination sub-module for constructing the stress change curve graph of different goafs according to the stress change rule, and determining the change trend of the stress coefficient peak according to the stress change curve graph; A dividing sub-module for dividing the stress change curve into a pressure increasing curve, a pressure decreasing curve and a pressure stabilizing curve according to the change trend of the stress coefficient peak; A fourth determination sub-module for respectively obtaining the spatio-temporal domain corresponding parameters of the pressure increasing curve, the pressure decreasing curve and the pressure stabilizing curve, and determining the pressure increasing area, the pressure decreasing area and the pressure stabilizing area of different goafs according to the spatio-temporal domain corresponding parameters; A fifth determination sub-module for determining the stress transition attribute according to the stress change parameters of the pressure increasing area, the pressure decreasing area and the pressure stabilizing area of different goafs, and determining the stress change characteristics of the pressure increasing area, the pressure decreasing area and the pressure stabilizing area of different goafs according to the stress transition attribute.

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