Rock penetration damage simulation method and system based on discrete element method

Abstract

The present invention discloses a rock penetration damage simulation method and system based on discrete element method, the method comprising: constructing a rock damage and crushing model; based on the discrete element method and the rock damage and crushing model, inputting parameters and conditions, and calculating particle force information; calculating particle velocity and displacement according to the particle force information to obtain calculation results; outputting the calculation results and drawing a damage cloud map. The system comprises: a constitutive model construction module, a first calculation module, a second calculation module and a result output module. By using the present invention, it is possible to effectively simulate phenomena such as crack generation and strength changes in rock penetration tests, and ensure production safety during the construction process. The present invention can be widely used in the field of geotechnical engineering.

Description

Technical Field

[0001] The invention relates to the field of geotechnical engineering, and in particular to a rock penetration damage simulation method and system based on discrete elements. Background Art

[0002] There is a complex interaction mechanism between tunnel excavation construction and the strata. When the construction process encounters unfavorable geological bodies such as karst, faults, and broken zones, it is possible to induce serious disasters such as water inrush, mud inrush, and landslides under construction disturbance, causing serious loss of life and property to the tunnel construction. Therefore, it is crucial to do a good job of advanced geological forecasting during tunnel construction for the smooth progress of tunnel construction. Advanced drilling is a direct and effective method in advanced geological forecasting. The drilling rig is used to drill holes on the tunnel face, and the drilling rig parameters and rock samples obtained during the drilling process are analyzed to infer the location and severity of the unfavorable geological body in front of the tunnel. Timely construction warnings can be carried out, and effective prevention and control measures can be taken to ensure the safety of construction.

[0003] Predicting the surrounding rock information in front of the tunnel face and giving early warning of geological disasters are the main tasks of advance forecasting. Digital advance drilling relies on establishing a quantitative relationship between drilling parameters and surrounding rock characteristics. Existing studies mainly use empirical judgment methods based on linear regression to establish a qualitative relationship between drilling parameters and surrounding rock characteristics. This method makes it difficult to distinguish the different degrees of rock damage during tunneling and penetration, and lacks a detailed description of the rock damage mechanism. Summary of the invention

[0004] In view of this, in order to solve the technical problem that the existing damage simulation method relies on the empirical judgment of linear regression and is difficult to accurately simulate the rock failure during tunnel excavation and penetration, the present invention proposes a rock penetration damage simulation method based on discrete elements, which includes the following steps:

[0005] A rock damage and crushing model is constructed to describe the mechanical state of rock particles when they are locally damaged.

[0006] Based on the discrete element method and the rock damage and crushing model, the parameters and conditions are input, and if the time step is not reached, the particle force information is calculated; if the time step is reached, the calculation results are directly output and the damage cloud map is drawn;

[0007] After all particles are traversed, the particle velocity and displacement are calculated according to the particle force information to obtain the calculation results;

[0008] The calculation results are output and a damage cloud diagram is drawn.

[0009] In some embodiments, based on the discrete element method and the rock damage and crushing model, the parameters and conditions are input, and if the time step is not reached, the step of calculating the particle force information specifically includes:

[0010] Initializing the parameters of the rock damage and crushing model, inputting material parameters, and determining the model size;

[0011] Determine discrete particle coordinates;

[0012] Number the discrete particles respectively and input the corresponding data information;

[0013] Imposing initial boundary conditions and determining the time step;

[0014] The particle force information is calculated according to the calculation rules of the rock damage and crushing model.

[0015] In some embodiments, in the rock damage and crushing model, there are an initial stage, a critical stage and a high strain stage, wherein:

[0016] In said initial stage, the rock material exhibits linear elastic behavior;

[0017] When the relative displacement continues to increase and exceeds a certain critical value, microscopic damage begins to occur inside the rock, such as the expansion of microcracks, and enters the critical stage. The normal force growth rate in this stage is usually higher than that in the initial stage, which is manifested as a steeper curve slope.

[0018] After entering the high strain region, the rock material may experience a certain amount of stress release or recompression. The slope of this stage is usually smaller than that of the previous two stages, indicating that the normal force growth of the material gradually slows down.

[0019] In some embodiments, it also includes:

[0020] Based on the rock damage and crushing model simulation experiment and comparison with the results obtained from actual experiments, the reliability of the rock damage and crushing model is verified.

[0021] The present invention also proposes a rock penetration damage simulation system based on discrete elements, the system comprising:

[0022] Constitutive model building module, used to build rock damage and crushing models;

[0023] The first calculation module calculates the particle force information based on the discrete element method and the rock damage and crushing model by inputting parameters and conditions;

[0024] A second calculation module is used to calculate the particle velocity and displacement according to the particle force information to obtain a calculation result;

[0025] The result output module is used to output the calculation results and draw a damage cloud map.

[0026] Based on the above scheme, the present invention provides a rock penetration damage simulation method and system based on discrete elements. A rock damage and crushing model is constructed according to the local damage state of rock during the rock penetration process, and it is applied to discrete element software to form a method for describing the integrity and strength characteristics of rock. Based on this method, a reference can be provided for predicting the degree of fracture of the surrounding rock of the face using the advance drilling downhole data, and unfavorable geological bodies can be predicted in time to ensure production safety during the construction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic flow chart of a rock penetration damage simulation method based on discrete elements of the present invention;

[0028] Figure 2 is a relationship diagram between the normal force and the relative normal displacement increment of the rock damage and crushing model of the present invention;

[0029] Figure 3 is a relationship diagram of normal force-relative displacement of the rock damage and crushing model of the present invention when the damage degree increases;

[0030] Figure 4 It is a schematic diagram of the definition of damage value;

[0031] Figure 5 This is a model diagram of rock penetration test;

[0032] Figure 6 It is a schematic diagram of the variation of penetration force and penetration pressure with penetration depth in the simulated penetration test;

[0033] Figure 7 This is a cloud diagram of the damage degree of the simulated penetration test;

[0034] Figure 8 This is a diagram of the bonding state of the simulated penetration test. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] It should be noted that, for the convenience of description, only the parts related to the relevant invention are shown in the drawings. In the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0037] It should be understood that the "system", "device", "unit" and / or "module" used in this application is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the word can be replaced by other expressions.

[0038] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

[0039] In the description of the embodiments of the present application, "plurality" means two or more than two. The following terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0040] In addition, flow charts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, the various steps may be processed in reverse order or simultaneously. At the same time, other operations may also be added to these processes, or a certain step or several steps of operations may be removed from these processes.

[0041] Reference Figure 1 , which is a flow chart of an optional example of a rock penetration damage simulation method based on discrete elements proposed in the present invention. The method can be applied to computer equipment. The simulation method proposed in this embodiment may include but is not limited to the following steps:

[0042] Step S1, constructing a rock damage and crushing model (new constitutive model);

[0043] Step S2, based on the discrete element method and the rock damage and crushing model, input parameters and conditions to calculate particle force information;

[0044] Step S3, calculating the particle velocity and displacement according to the particle force information to obtain a calculation result;

[0045] Step S4, outputting the calculation results and drawing a damage cloud map;

[0046] Step S5: verify the rock damage and crushing model in combination with the indoor penetration test scheme.

[0047] In some feasible embodiments, the step S1 specifically includes:

[0048] A rock damage and crushing model is constructed to describe the mechanical state of rock particles when they are locally damaged. When constructing the model, the deformation and damage stages are divided and the dynamic damage value of rock particles is introduced. This can reduce the bond strength between particles according to the degree of damage at the current moment, thereby reflecting the integrity of the rock sample. At the same time, it can more comprehensively describe the mechanical behavior of rock materials in penetration tests, especially the complex process of gradual damage and recompression.

[0049] First, in the initial stage with small strain, rock materials usually exhibit linear elastic behavior. Figure 2 As shown in , for the normal tension, the inter-particle force at this stage is proportional to the relative displacement increment between particles, and the slope (stiffness) is large, which reflects the initial elastic modulus of the rock material. is the cross-sectional area, , the normal contact stiffness coefficient in the initial stage , is the normal force at the previous time step, is the relative normal displacement increment. The normal bonding force between particles at this stage is calculated according to the following formula:

[0050]

[0051] in, represents the normal force at the current time step in the initial stage, Represents a parallel bond. The mechanical properties of this model after bond failure are similar to those of the parallel bond model. Therefore, the parallel bond form is also used in the definition. Therefore, this horizontal line is used to represent the force and other parameters on the parallel bond when the bond has not yet broken.

[0052] When the relative displacement continues to increase and exceeds a certain critical value, microscopic damage begins to occur inside the rock, such as the expansion of microcracks. This process is the critical stage. The normal force growth rate at this stage is usually faster than the initial stage, which is manifested as a steeper curve slope. The normal force changes at this stage are as follows:

[0053]

[0054] in, represents the normal force at the current time step in the critical phase, represents the normal contact stiffness coefficient in the critical stage, is the first relative normal displacement threshold, is the normal force offset in the critical stage, which is used to ensure the continuity of the curve.

[0055] After entering the high strain area, the rock material may experience a certain amount of stress release or recompression, which is the high strain stage. The slope of this stage is usually smaller than that of the previous two stages, indicating that the normal force growth of the material gradually slows down.

[0056]

[0057] in, represents the normal force at the current time step in the high strain phase, represents the normal contact stiffness coefficient in the high strain stage, represents the second relative normal displacement threshold, Represents the normal force offset during the high strain stage, also used to ensure the continuity of the curve.

[0058] For the tangential force, it is also calculated according to the initial stage, critical stage and high strain stage, and the formula is as follows:

[0059]

[0060] in, represents the tangential force at the current time step in the critical stage, represents the tangential contact stiffness coefficient in the initial stage, represents the cross-sectional area, Represents the relative tangential displacement increment; represents the tangential force at the current time step in the critical stage, represents the tangential contact stiffness coefficient in the critical stage, represents the first relative tangential displacement threshold, represents the tangential force offset in the critical stage; represents the tangential force at the current time step in the high strain stage, represents the tangential contact stiffness coefficient in the high strain stage, represents the second relative tangential displacement threshold, represents the tangential force offset in the high strain stage.

[0061] The new constitutive model describes the mechanical state between particles at the particle level. The relative displacement threshold mentioned needs to be calibrated according to the actual situation in order to fit the actual data curve.

[0062] In some feasible embodiments, the step S2 specifically includes:

[0063] The force and displacement state between discrete particles are calculated using the basic principle of the discrete element method. The discrete element method is based on the force-displacement law and Newton's second equation. First, the contact force generated by the contact part of the particles is updated through the force-displacement law, and then the position information of the particles is updated through Newton's second equation to readjust the contact relationship between the particles. All particles need to be traversed in the calculation of each time step until the model reaches equilibrium or is destroyed.

[0064] For the contact between particles, there is a relationship:

[0065]

[0066] in, Indicates i For the normal force between particles, Indicates i The increment of the tangential force between particles is and are the normal contact stiffness coefficient and the tangential contact stiffness coefficient, respectively. For the i For the contact normal vector between particles, is the relative displacement in the contact normal direction, is the relative tangential displacement of contact.

[0067] When the particles have not reached equilibrium, their average acceleration and rotational acceleration are as follows:

[0068]

[0069]

[0070] in, express The average acceleration at time, express The rotational acceleration at the moment, and are the unbalanced force and unbalanced moment in the horizontal direction, is the angular momentum.

[0071] By integrating the above formula in the form of forward difference, we can calculate The velocity and rotation speed of the particle in the horizontal direction at :

[0072]

[0073] in, Indicates that the particles are in the horizontal direction The speed of time, Indicates that the particles are in the horizontal direction The rotation speed at the moment.

[0074] The discrete element calculation software is used for simulation. The discrete element calculation software uses the C++ language in Visual Studio as the development platform, and the graphical interface design is implemented using the C++-based OpenGL library. The software calculation simulation will be implemented through multiple modules, including modeling, contact determination, constitutive model application, force displacement calculation, wall loading and history monitoring. Each module is interconnected and can also be edited independently, which is convenient for adapting to different model conditions and solving various problems.

[0075] The Hoek–Brown failure criterion is used to determine the failure state between particles. If the particles reach the Hoek–Brown failure criterion, it is considered as a bond fracture.

[0076] like Figure 3 In the discrete element method, a damage value is set for each particle. The value is determined by the bonding state of the current particle and the surrounding particles, and the value is between 0 and 1. This value is a dimensionless quantity used to describe the degree of damage of the material under a certain state. Indicates that the material is in a non-damaged state. Indicates that the material is completely destroyed. Damage value The calculation method of is defined as:

[0077]

[0078] in, is the number of bonds generated by the particle in the initial state of the model, is the number of bonds remaining in the particle at the current time step. The larger the damage value, the greater the degree of damage around the particle. The force and damage of the particle bond are affected by this. When the damage value of the particle is relatively large, the corresponding bond force will be reduced, and the peak strength at the time of damage will also be reduced. The bond state and bond fracture state between particles refer to Figure 4 .

[0079] In the rock damage and crushing model, the force on the damaged particles is calculated according to the different degrees of particle damage, such as Figure 3 As shown in the figure, taking the normal force as an example, the normal force generated by the damaged particles will be lower than that of the undamaged particles to a certain extent. In damage mechanics, it is assumed that the mechanical behavior of the material can be described by an effective undamaged material, and the stress of the effective material is called "effective stress". The relationship between the effective stress and the actual stress is usually described by the damage variable. In the calculation of the normal force between particles, the inter-particle bonding force will be multiplied by an attenuation factor, which is determined by the damage value. Define the original normal force as ,Right now Figure 2 The normal force calculated in , the original tangential force is defined as , assuming the damage value is , then the normal force and tangential force generated by the damaged particle will be calculated by the following formula:

[0080]

[0081] in, represents the corrected normal force, represents the corrected tangential force.

[0082] Dynamically calculates the particle's damage value and force at each time step, and adjusts the uncorrected normal force based on the damage value With the uncorrected tangential force , use the corrected forces for stress calculations.

[0083] That is, the normal force and tangential force of the current time step in each stage are first calculated by the relative displacement increment, and then adjusted by the damage value.

[0084] If the damage values ​​of the two particles corresponding to the bonding are inconsistent, the average value of the two is taken to balance the damage effects of the two particles, that is:

[0085]

[0086] in, and They are the damage values ​​of two different particles respectively, which can reasonably reflect the average damage effect of the interaction between the two particles, making the model more physically meaningful and reasonable.

[0087] When the particle damage value changes, its stress-strain relationship curve will show a mutation. During the penetration test, if a large-scale bond failure occurs in a certain area, the average particle damage value in this area will increase sharply, causing the stress of the sample to drop.

[0088] In some feasible embodiments, the step S2 specifically includes the following steps:

[0089] S2.1. Initialize the rock damage and crushing model, input material parameters, and determine the model size;

[0090] Specifically, taking the plane problem as an example, it is necessary to determine the length, width, elastic modulus, density, damping coefficient, etc. of the model;

[0091] S2.2, determine the coordinates of discrete particles;

[0092] S2.3. Number the discrete particles respectively and input the corresponding data information;

[0093] S2.4, apply initial boundary conditions and determine the time step;

[0094] The bottom of the sample is the fixed boundary, and the rest are free boundaries. If the time step is too short, the instantaneous displacement of the particles will be too large, and if the time step is too long, the calculation efficiency will be too low. Therefore, a suitable time step value needs to be selected.

[0095] S2.5. If the time step is not reached, the particle force information is calculated according to the calculation rules of the rock damage and crushing model; if the time step is reached, the calculation results are directly output and a damage cloud map is drawn.

[0096] In some feasible embodiments, the step S3 specifically includes:

[0097] After calculating the particle force according to the calculation rule of the rock damage and crushing model, it is determined whether the program has traversed all discrete particles. If not, the particle force is calculated again according to the calculation rule of the rock damage and crushing model. If all discrete particles have been traversed, the particle velocity and displacement are calculated.

[0098] In some feasible embodiments, the step S5 specifically includes:

[0099] Based on this constitutive model, the reliability of the constitutive model is verified by simulating rock penetration tests and comparing the results with those obtained from actual tests. Figure 5 As shown in Figure 1, the particle model used in the discrete element simulation is constructed according to the model of the actual rock penetration test. According to the distribution of rock cracks, the geological strength index GSI is 100. The specific value is based on the GSI value method proposed by HOEK et al. When there are no more than two obvious through cracks on the rock surface, the value is GSI=100.

[0100] The test used a wedge-shaped tool shape. Tool tilt angle , cone width , the loading rate is set to 0.5 mm / min, and the test is started until the sample is completely penetrated. The measurement data during the penetration process is obtained by the electronic universal material testing machine.

[0101] The penetration depth is taken as the tool displacement measured by the electronic universal material testing machine, and the penetration pressure is the ratio of the penetration force to the projected area of ​​the rock penetrated by the tool, which is obtained by the following formula:

[0102]

[0103] in, For penetration, is the penetration depth, is the tool inclination angle. The relationship between penetration pressure and penetration depth is calculated using this formula. The test data are as follows: Figure 6As shown in the figure. At the initial penetration, the penetration force shows a linear trend with the increase of penetration depth. Afterwards, the penetration force drops sharply to a certain extent, indicating that the rock sample is locally brittle during the penetration process, resulting in the collapse of small rock blocks. At this time, the penetration probe enters the rock mass to form a crushing zone. From the comparison of rock samples with different integrity, it is known that this sudden drop process is more obvious in slightly intact rocks. Subsequently, the penetration force decreases at a rate of increase with the penetration depth until the penetration force further increases to a peak value.

[0104] The maximum penetration pressure obtained from the test can be used to indicate the maximum pressure required for the rock to resist external forces without deformation, and the moment when the maximum pressure occurs is accompanied by a sharp increase in the number of acoustic emissions. This pressure can be used to indicate the rock's fracture initiation pressure. For relatively intact rocks, the maximum penetration pressure is usually relatively large.

[0105] Combined with the indoor penetration test scheme, the rock sample model and probe model were constructed in the discrete element software. The probe was simulated by the wall element, and the loading behavior of the probe on the rock sample was realized according to the mechanical relationship between the wall and the particles.

[0106] Build A rectangular particle model is used to simulate the cross-sectional model of the rock sample under two-dimensional conditions. , , The rock strength parameters are determined to define the failure law and damage law of the constitutive model between particles. The parameters are calibrated by trial and error method to determine other relevant parameters of the constitutive model and obtain a particle model whose mechanical state is as close to the actual rock sample as possible.

[0107] A loading rate of 0.5 mm / min is applied to the probe model, and the force applied to the probe is dynamically monitored during the penetration process, which is the penetration force in the simulation test. The displacement of the penetration probe is also monitored to obtain the penetration depth.

[0108] The test data obtained are as follows Figure 6 As shown. Comparing the discrete element simulation results with the indoor penetration test results, it can be seen that the simulation result curve first increases linearly, and then presents a bimodal shape similar to the actual test results, which indicates that the change in particle damage caused by the change in the inter-particle bonding state during the penetration process leads to a change in the degree of sample damage. This constitutive model explains the effect of damage on the inter-particle bonding strength from the particle level, and also shows the effect of particle damage on the overall rock sample strength, which is similar to the actual test results. Comparing the simulation test results under different rock integrity, it can be seen that the simulation test also obtained a similar rule: the smaller the degree of rock fragmentation, the more difficult it is to cause macroscopic brittle failure.

[0109] Further observation of the penetration pressure curve shows that when the probe penetrates into the rock mass and causes certain damage, the penetration pressure also fluctuates. The maximum penetration pressure can be used to indicate the maximum pressure required for the rock to resist external forces without deformation, and the crack expansion rate also increases sharply when the maximum penetration pressure occurs. Therefore, the maximum penetration pressure can be used to indicate the cracking pressure of the rock mass.

[0110] The damage cloud diagram and bonding state cloud diagram of the sample during the simulation process are shown in Figure 7 and Figure 8 The particle damage value affects the cohesion of the particles. As shown in the figure, the parts with greater damage are concentrated at the penetration probe, which is also the concentration point of cracks. The particles in this area will be affected by the surrounding cohesion fracture, and the inter-particle force generated will be reduced, resulting in the generation of cracks and further fragmentation of the rock sample.

[0111] A rock penetration damage simulation system based on discrete element, comprising:

[0112] Constitutive model building module, used to build rock damage and crushing models;

[0113] The first calculation module calculates the particle force information based on the discrete element method and the rock damage and crushing model by inputting parameters and conditions;

[0114] A second calculation module is used to calculate the particle velocity and displacement according to the particle force information to obtain a calculation result;

[0115] The result output module is used to output the calculation results and draw a damage cloud map.

[0116] The contents of the above method embodiments are all applicable to the present system embodiments. The functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0117] A rock penetration damage simulation device based on discrete element method:

[0118] at least one processor;

[0119] at least one memory for storing at least one program;

[0120] When the at least one program is executed by the at least one processor, the at least one processor implements the rock penetration damage simulation method based on discrete elements as described above.

[0121] The contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0122] A storage medium stores instructions executable by a processor, wherein the instructions executable by the processor are used to implement a rock penetration damage simulation method based on discrete elements as described above when executed by the processor.

[0123] The contents of the above method embodiments are all applicable to the present storage medium embodiments. The functions specifically implemented by the present storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0124] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A rock penetration damage simulation method based on discrete element, characterized in that: The following steps are involved: Construct rock damage and crushing model; Based on the discrete element method and the rock damage and crushing model, the parameters and conditions are input to calculate the particle force information; Calculate the particle velocity and displacement according to the particle force information to obtain a calculation result; Outputting the calculation results and drawing a damage cloud map; The step of inputting parameters and conditions based on the discrete element method and the rock damage and crushing model to calculate the particle force information specifically includes: Initializing the rock damage and crushing model; Input material parameters; Determine particle coordinates; Number the particles separately and enter the corresponding data information; Imposing initial boundary conditions and determining the time step; Calculating particle force information according to the calculation rules of the rock damage and crushing model; In the rock damage and crushing model, there are initial stage, critical stage and high strain stage, among which: In the initial stage, the rock material exhibits linear elastic behavior; In the critical stage, the normal force increases faster than in the initial stage; In the high strain stage, the normal force growth rate is lower than that in the initial stage; In the rock damage and crushing model, the change of normal force in the parallel bond is expressed as follows: During the initial phase: Among them, F n1 represents the normal force at the current time step in the initial stage, F n represents the normal force at the previous time step, k n,1 represents the normal contact stiffness coefficient in the initial stage, A represents the cross-sectional area, Δδ n is the relative normal displacement increment, represents parallel bonds; During the critical phase: Among them, F n2 represents the normal force at the current time step in the critical stage, k n,2 represents the normal contact stiffness coefficient in the critical stage, δ n,TH1 represents the first relative normal displacement threshold, F n,OF2 represents the normal force offset in the critical stage; During the high strain phase: Among them, F n3 represents the normal force at the current time step in the high strain stage, k n,3 represents the normal contact stiffness coefficient in the high strain stage, δ n,TH2 represents the second relative normal displacement threshold, F n,OF3 represents the normal force offset in the high strain stage; In the rock damage and crushing model, the change of the tangential force in the parallel bond is expressed as follows: During the initial phase: Among them, F s1 represents the tangential force at the current time step in the initial stage, k s,1 represents the tangential contact stiffness coefficient in the initial stage, Δδ s Represents the relative tangential displacement increment; During the critical phase: Among them, F s2 represents the tangential force at the current time step in the critical stage, k s,2 represents the tangential contact stiffness coefficient in the critical stage, δ s,TH1 represents the first relative tangential displacement threshold, F s,OF2 represents the tangential force offset in the critical stage; During the high strain phase: Among them, F s3 represents the tangential force at the current time step in the high strain stage, k s,3 represents the tangential contact stiffness coefficient in the high strain stage, δ s,TH2 represents the second relative tangential displacement threshold, F s,OF3 represents the tangential force offset in the high strain stage.

2. The rock penetration damage simulation method based on discrete element according to claim 1 is characterized in that: The step of calculating the particle force information according to the calculation rule of the rock damage and crushing model also includes: The force on the particles is corrected according to the damage value, and the formula is as follows: Among them, F n modified represents the corrected normal force, F s modified represents the corrected tangential force, F n,pre represents the uncorrected normal force, F s,pre represents the uncorrected tangential force and D represents the damage value.

3. The rock penetration damage simulation method based on discrete element according to claim 1 is characterized in that: Also includes: Combined with the indoor penetration test scheme, the rock damage and crushing model is verified.

4. A rock penetration damage simulation system based on discrete element, characterized in that: The method for simulating rock penetration damage based on discrete elements as claimed in claim 1 comprises: Constitutive model building module, used to build rock damage and crushing models; The first calculation module calculates the particle force information based on the discrete element method and the rock damage and crushing model by inputting parameters and conditions; A second calculation module is used to calculate the particle velocity and displacement according to the particle force information to obtain a calculation result; The result output module is used to output the calculation results and draw a damage cloud map.

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