Measurement methods and systems for explosion pressure and crack propagation process around deep hole blasting boreholes.

Abstract

This invention provides a method and system for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole, relating to the field of blasting test and analysis technology. Specific steps include: using the mechanical parameters of the sample, borehole parameters, and explosive parameters as input parameters, performing a finite element simulation of the blasting process in the area surrounding the borehole to obtain the pressure values ​​at each coordinate point at each time point within the borehole area; combining the stress reduction coefficient related to distance to obtain the internal equivalent stress correction value, thereby determining the crack initiation coordinate point; for any crack initiation coordinate point, extracting its associated coordinate point within its associated time window, and inverting the crack propagation process in the area surrounding the borehole. This invention determines the crack initiation coordinate point through the internal equivalent stress correction value, extracts its associated coordinate point within its associated time window, and connects the crack initiation coordinate point and the associated point to ensure that the inverted crack propagation process in the area surrounding the borehole closely matches the actual blasting conditions.

Description

Technical Field

[0001] This invention relates to the field of blasting test and analysis technology, specifically to a method and system for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole. Background Technology

[0002] Blasting is widely used in mining, water conservancy projects, and transportation construction. The distribution of explosion pressure and crack propagation process around the blast hole directly determines the blasting effect, construction safety, and project economy. Therefore, accurate measurement of explosion pressure and crack propagation process around the blast hole is of great significance for optimizing blasting parameters, reducing construction risks, and improving project efficiency. Currently, the industry mostly uses simulation combined with experimental analysis to measure explosion pressure and crack propagation process around the blast hole.

[0003] In the prior art, CN120930413A discloses a method, device, storage medium, and electronic device for monitoring the operating status of a motor. It focuses on the field of motor control and realizes the monitoring of the operating status and fault protection of the motor by acquiring motor status information, analyzing fault identifiers, and calculating limit values.

[0004] CN117388095A discloses a method and system for measuring the explosion pressure and crack propagation process around a blast hole, comprising the following steps: performing blasting simulation on a blasting physics model and acquiring the simulation data; analyzing the explosion stress distribution and crack propagation law around the blast hole in the blasting physics model based on the simulation data; obtaining the explosion pressure around the blast hole by combining the explosion stress distribution and the simulation data; and obtaining the crack propagation process around the blast hole by combining the crack propagation law and the simulation data. This method simulates and analyzes the explosion stress distribution and crack propagation law around the blast hole in a blasting physics model to obtain the explosion pressure and crack propagation process around the blast hole. Based on this, the experimental scheme of the blasting physics model is adjusted and the simulation is further refined to continuously improve the reliability of the simulation results.

[0005] However, the existing technology still has the following shortcomings: it does not accurately bind the discrete data of explosion pressure to each spatial coordinate point in the sample, and cannot clearly define the distribution characteristics of explosion pressure at different spatial locations, thus failing to establish a spatial-mechanical relationship between explosion pressure and crack propagation; at the same time, it does not consider the attenuation law of explosion stress along the radial distance of the borehole during blasting, which causes deviations in stress calculation, thereby affecting the determination of crack initiation coordinate points and associated coordinate points, and reducing the accuracy of crack propagation process inversion.

[0006] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole, comprising the following steps:

[0010] S1. Select specimens in the area around the borehole for mechanical loading tests. Calculate the mechanical parameters of the specimens based on the load and deformation parameters collected during the test. At the same time, collect the borehole parameters before blasting and the explosive parameters inside the borehole.

[0011] S2. Using the mechanical parameters of the sample, the borehole parameters, and the explosive parameters inside the borehole as input parameters, a finite element simulation of the blasting process in the area surrounding the borehole is performed. Starting from the blasting moment, the pressure values ​​of each coordinate point in the area surrounding the borehole at each moment within a preset time period are obtained.

[0012] S3. Based on the mechanical parameters of the sample and the internal stress state of each coordinate point in the area around the blast hole during blasting, construct a pressure-stress conversion model, input the pressure value, obtain the internal equivalent stress value of each coordinate point at each moment within a preset time period, determine the area to which each coordinate point belongs based on the distance between each coordinate point and the blast hole, and assign the corresponding stress reduction coefficient. Based on the stress reduction coefficient, obtain the corrected value of the internal equivalent stress of each coordinate point at each moment.

[0013] S4. Compare the internal equivalent stress correction value of each coordinate point at each time with the preset stress threshold to obtain the crack initiation time of each coordinate point, and regard this coordinate point as the crack initiation coordinate point at this time.

[0014] S5. For any crack initiation coordinate point, extract its associated coordinate points within its associated time window, and connect the crack initiation coordinate points and associated coordinate points extracted at all times within a preset time period to obtain the crack propagation process in the area surrounding the borehole.

[0015] Furthermore, the load and deformation parameters include axial load, displacement, and strain; the mechanical parameters include compressive strength, tensile strength, and elastic modulus; the borehole parameters include borehole diameter and depth; and the explosive parameters include explosive detonation pressure, detonation velocity, and charge amount.

[0016] Furthermore, based on the mechanical parameters of the specimen and the internal stress state of each coordinate point in the area surrounding the blast hole during blasting, a pressure-stress conversion model is constructed, with the specific logic as follows:

[0017] If the internal stress state of a coordinate point at a certain moment is under tension, the tensile strength of the coordinate point at this moment is calculated by the ratio of the elastic modulus to the tensile stress proportionality coefficient. The tensile stress proportionality coefficient is then used as the adaptive proportionality coefficient of the coordinate point at this moment.

[0018] If the internal stress state of a coordinate point at a certain moment is under compression, the compressive strength of the coordinate point at this moment is calculated by the ratio of the elastic modulus to the compressive stress proportionality coefficient. The compressive stress proportionality coefficient is then used as the adaptive proportionality coefficient of the coordinate point at this moment.

[0019] The expression for the pressure-stress conversion model is: the internal equivalent stress value is equal to the product of the adaptive scaling factor and the pressure value;

[0020] If the adaptive scaling factor is the tensile stress scaling factor, then the internal equivalent stress value is the internal tensile stress value.

[0021] If the adaptive scaling factor is the compressive stress scaling factor, then the internal equivalent stress value is the internal compressive stress value.

[0022] Furthermore, based on the distance between each coordinate point and the borehole, the region to which that coordinate point belongs is determined, and the corresponding stress reduction coefficient is assigned. The specific logic is as follows:

[0023] Based on the distance between each coordinate point and the borehole, the area around the borehole is divided into the near-core area, the stress attenuation transition area, and the far-field diffusion area.

[0024] If the distance between a coordinate point and the borehole Greater than or equal to 0 and less than 3 times the borehole diameter The coordinate point belongs to the near-core area of ​​the borehole, and the stress reduction factor assigned to this coordinate point is 1.0;

[0025] If the distance between a coordinate point and the borehole Greater than or equal to 3 times the borehole diameter And less than 10 times the borehole diameter The coordinate point belongs to the stress attenuation transition zone, and the stress reduction factor assigned to the coordinate point is 0.8;

[0026] If the distance between a coordinate point and the borehole ≥10 times the borehole diameter The coordinate point belongs to the far-field diffusion region, and the stress reduction factor assigned to this coordinate point is 0.6;

[0027] Based on the distance between each coordinate point and the borehole, the corresponding area is determined, and then the stress reduction coefficient corresponding to that coordinate point is obtained.

[0028] Furthermore, the internal equivalent stress correction value at each coordinate point at each time is obtained based on the stress reduction factor. The specific logic is as follows:

[0029] For the distance between each coordinate point and the borehole, extract the corresponding stress reduction factor;

[0030] Multiply the internal equivalent stress value of each coordinate point at each time point by the corresponding stress reduction factor to obtain the corrected internal equivalent stress value of each coordinate point at each time point.

[0031] Furthermore, the internal equivalent stress correction value of each coordinate point at each time moment is compared with the preset stress threshold to obtain the crack initiation time of each coordinate point. The specific logic is as follows:

[0032] For any coordinate point, the moment when its internal equivalent stress correction value first rises from less than the stress threshold to equal to or greater than the stress threshold is extracted. This moment is defined as the crack initiation moment of this coordinate point, that is, this coordinate point is regarded as the crack initiation coordinate point at this moment.

[0033] Furthermore, for any crack initiation coordinate point, its associated coordinate points are extracted within its associated time window. The specific logic is as follows:

[0034] Starting from the moment of detonation, for any moment within a preset time period, a related time window is determined for that moment, and the related time window is located before that moment.

[0035] For any crack initiation coordinate point extracted at this moment, the distance between it and each crack initiation coordinate point in the associated time window is calculated one by one. Crack initiation coordinate points in the associated time window whose distance from this crack initiation coordinate point is less than a preset threshold are extracted and used as associated coordinate points of this crack initiation coordinate point.

[0036] If there are no associated coordinate points, then the coordinate point where the crack initiation occurs will not be used as the extension point.

[0037] If there is only one associated coordinate point, then the coordinate point where the crack initiation occurs shall be taken as the extension point of the associated coordinate point.

[0038] If there is more than one associated coordinate point, the associated coordinate point with the smallest distance from the crack initiation coordinate point is selected as the preferred coordinate point, and the crack initiation coordinate point is used as the extension point of the preferred coordinate point.

[0039] If there is more than one preferred coordinate point, the priority of each preferred coordinate point is extracted one by one, and a preferred coordinate point with a priority no lower than that of the crack initiation coordinate point is selected as the preceding coordinate point.

[0040] If there is only one preceding coordinate point, take the crack initiation coordinate point as the extension point of the preceding coordinate point.

[0041] If there is more than one preceding coordinate point, for any preceding coordinate point, based on the correspondence of the extension points, determine the crack curve segment where the preceding coordinate point is located, calculate the average curvature of each crack curve segment, connect each crack curve segment with the crack initiation coordinate point to obtain each complete crack curve, and calculate the average curvature of each complete crack curve.

[0042] Assign priority values ​​to the coordinate points in the area surrounding the borehole, as follows:

[0043] If a coordinate point is located near the core area of ​​the borehole, its priority is assigned a value of 3;

[0044] When a coordinate point is located in the stress attenuation transition zone, its priority is assigned a value of 2;

[0045] If a coordinate point is located in the far-field diffusion region, its priority is assigned to 1;

[0046] Calculate the absolute change in average curvature between each crack curve segment and the complete crack curve, calculate the difference in priority between each preceding coordinate point and the crack initiation coordinate point, and weight the difference in normalized average curvature and priority to obtain the comprehensive evaluation coefficient of each complete crack curve.

[0047] The preceding coordinate point corresponding to the minimum comprehensive evaluation coefficient is taken as the target coordinate point, and the crack initiation coordinate point is taken as the extension point of the target coordinate point.

[0048] To achieve the above objectives, the present invention also provides the following technical solution:

[0049] A measurement system for the explosion pressure and crack propagation process around a deep-hole blasting borehole, the system being used to perform any of the above-described methods for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole, comprising:

[0050] The data acquisition module is used to select samples for mechanical loading tests. Based on the load and deformation parameters collected during the test, the mechanical parameters of the samples are calculated. At the same time, the deep hole parameters before blasting and the explosive parameters in the deep hole are collected.

[0051] The data simulation module is used to perform finite element simulation of the blasting process of the sample using the mechanical parameters, deep hole parameters and explosive parameters of the sample as input parameters. Starting from the blasting time, it obtains the pressure values ​​of each coordinate point in the area around the blast hole at each time within a preset time period.

[0052] The data correction module is used to construct a pressure-stress conversion model based on the mechanical parameters of the sample and the internal stress state of each coordinate point in the area around the blast hole during blasting. By inputting the pressure value, the internal equivalent stress value of each coordinate point at each moment within a preset time period is obtained. Based on the distance between each coordinate point and the blast hole, the corresponding stress reduction coefficient is determined. Based on the stress reduction coefficient, the internal equivalent stress correction value of each coordinate point at each moment is obtained.

[0053] The comparison module is used to compare the internal equivalent stress correction value of each coordinate point at each time with the preset stress threshold to obtain the crack initiation time of each coordinate point, and at that time, this coordinate point is regarded as the crack initiation coordinate point.

[0054] The process inversion module is used to extract the associated coordinates of any crack initiation coordinate point within its associated time window, and to sequentially connect the crack initiation coordinates and associated coordinates extracted at all times within a preset time period to obtain the crack propagation process in the area surrounding the borehole.

[0055] Compared with the prior art, the beneficial effects of the present invention are:

[0056] This invention uses the mechanical parameters of the sample, the borehole parameters, and the explosive parameters inside the borehole as input parameters to perform finite element simulation of the blasting process in the area surrounding the borehole. Starting from the blasting moment, it obtains the pressure values ​​of each coordinate point in the area surrounding the borehole at each moment within a preset time period, thus realizing the binding of the explosion pressure value with each coordinate point. This establishes a spatial-mechanical correlation between the explosion pressure value and crack propagation, effectively solving the technical problems of mismatch between explosion pressure value and spatial location and inability to clearly define the explosion pressure distribution characteristics at different spatial locations in the prior art. It provides pressure data and correlation basis for the inversion of the crack propagation process.

[0057] Meanwhile, based on the mechanical parameters of the sample and the internal stress state of each coordinate point in the area surrounding the borehole during blasting, this invention constructs a pressure-stress conversion model to obtain the internal equivalent stress value of each coordinate point at each moment within a preset time period. The corresponding stress reduction coefficient is determined according to the distance between each coordinate point and the borehole, and the internal equivalent stress value is specifically corrected to obtain the corrected internal equivalent stress value. This aligns with the objective law of the radial attenuation of explosive stress along the borehole during borehole blasting. The obtained corrected internal equivalent stress value also provides a basis for determining the crack initiation coordinate point. For any crack initiation coordinate point, its associated coordinate point is extracted within its associated time window. The crack initiation coordinate points and associated coordinate points extracted at all moments within the preset time period are sequentially connected to ensure that the crack propagation process in the area surrounding the borehole obtained from the inversion closely matches the actual working conditions of borehole blasting. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the overall method flow of the present invention;

[0059] Figure 2 This is a schematic diagram of the region division and stress reduction factor of the present invention;

[0060] Figure 3 This is a schematic diagram of crack propagation node tracing in this invention;

[0061] Figure 4 This is a block diagram of the module combination of the present invention. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0063] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0064] Example:

[0065] Please see Figures 1-3 The present invention provides a technical solution:

[0066] A method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole, comprising the following steps:

[0067] S1. Select specimens in the area around the borehole for mechanical loading tests. Calculate the mechanical parameters of the specimens based on the load and deformation parameters collected during the test. At the same time, collect the borehole parameters before blasting and the explosive parameters inside the borehole.

[0068] Among them, the sample refers to the rock specimen selected and processed from the rock mass surrounding the borehole.

[0069] Based on the above embodiments, the load and deformation parameters include axial load, displacement, and strain; the mechanical parameters include compressive strength, tensile strength, and elastic modulus; the borehole parameters include borehole diameter and depth; and the explosive parameters include explosive detonation pressure, detonation velocity, and charge amount.

[0070] Among them, axial load refers to the force applied along the axis of the specimen in the mechanical loading test. It is the core loading force that drives the specimen to deform and obtain mechanical properties, and is used to calculate the stress on the specimen.

[0071] Displacement refers to the absolute change in axial position of a specimen under axial load in a mechanical loading test. It reflects the degree of deformation of the specimen after being subjected to force and is the basic data for calculating strain and deriving mechanical parameters.

[0072] Strain refers to the amount of deformation per unit length of a specimen after it is subjected to force. It is calculated from the collected displacement data and directly reflects the deformation state of the specimen. It is the key to plotting stress-strain curves and determining mechanical parameters.

[0073] The diameter of the borehole refers to its internal diameter, which directly determines the borehole's geometry and affects the transmission range of blasting pressure and the accuracy of finite element simulation.

[0074] The borehole depth refers to the vertical depth of the borehole from the opening to the bottom. Together with the diameter, it constitutes the borehole geometry model and provides boundary conditions for finite element simulation.

[0075] The explosive pressure refers to the instantaneous pressure generated when an explosive detonates inside a borehole. It is a key parameter representing blasting energy and directly determines the intensity of the force generated by the blast.

[0076] The detonation velocity of an explosive refers to the speed at which the detonation wave propagates when the explosive explodes inside the borehole. It reflects the intensity of the explosion and the rate of energy release, and is a key basis for calculating blasting energy and constructing stress conversion models.

[0077] The charge amount of explosives refers to the total mass of explosives actually loaded into the borehole. It directly determines the total energy generated by the blast and is a key parameter for blast energy input in finite element simulation, affecting the pressure and stress distribution around the borehole.

[0078] Among them, the acquisition of axial load, displacement and strain: During the mechanical loading test, the load sensor built into the mechanical testing machine is used to collect axial load data, and the displacement sensor is used simultaneously to collect the axial displacement data of the specimen; by attaching strain gauges to the surface of the specimen and combining them with a strain acquisition instrument, the strain data of the specimen during the loading process is collected in real time. All data are recorded and stored synchronously to ensure the consistency of the data sequence.

[0079] Collection of borehole diameter and depth: Before blasting, the inner diameter of the borehole is directly measured using a borehole gauge. The average value of multiple measurements is taken as the borehole diameter. The depth of the borehole is measured by inserting a measuring rope into the bottom of the borehole using a depth gauge. The measurement is repeated 3-5 times. After removing outliers, the average value is taken as the borehole depth.

[0080] Data collection of explosive detonation pressure, detonation velocity, and charge quantity: Detonation pressure and detonation velocity are directly obtained from the factory standard parameters of this type of explosive. The charge quantity is accurately measured by electronic scale, and the total mass of explosive actually loaded into the borehole is recorded.

[0081] Based on the above embodiments, the mechanical parameters of the specimen are calculated according to the load and deformation parameters collected during the experiment. The specific logic is as follows:

[0082] First, an axial load is applied to the specimen and then gradually increased. Displacement and strain data are collected under each load level. Then, the stress is calculated using the load and the area of ​​the specimen subjected to force, and the strain is obtained using the collected strain data. Finally, the stress is plotted. The stress-strain curve has stress on the vertical axis and strain on the horizontal axis. The highest stress value that appears on the curve is the peak stress. When the test is a compressive load, the peak stress is the maximum compressive stress that the specimen can withstand, i.e., the compressive strength. When the test is a tensile load, the peak stress is the maximum tensile stress that the specimen can withstand, i.e., the tensile strength. Finally, the elastic modulus is calculated based on the slope of the elastic segment of the curve.

[0083] The elastic segment of the stress-strain curve refers to the line segment in which stress and strain are linearly proportional in the initial stage of loading. The core definition of the elastic modulus is the "ratio of stress to strain". The slope of this linear segment is equal to the absolute change in stress / the absolute change in strain. Since stress and strain are proportional in the elastic segment, the values ​​of "stress / strain" and "absolute change in stress / absolute change in strain" are equal. Therefore, the slope of this linear segment is the elastic modulus of the specimen, reflecting the specimen's ability to resist elastic deformation.

[0084] S2. Using the mechanical parameters of the sample, the borehole parameters, and the explosive parameters inside the borehole as input parameters, a finite element simulation of the blasting process in the area surrounding the borehole is performed. Starting from the blasting time, the pressure values ​​of each coordinate point in the area surrounding the borehole at each time within a preset time period are obtained.

[0085] The area surrounding the borehole is a three-dimensional cylindrical region defined by the borehole's central axis, with a radial range of 0 to 15 times the borehole diameter and an axial range of 0.8 to 1.2 times the borehole depth. These numerical ranges are determined by considering the rapid radial decay of the blasting pressure and the actual impact range of the borehole layout and blasting action at the engineering site.

[0086] Among them, the finite element simulation is carried out using a pre-constructed finite element model that matches the actual blasting scenario. Through mesh generation, boundary loading, and time-series solution, the spatiotemporal distribution of the blasting pressure field is simulated.

[0087] Based on the above embodiments, the construction logic of the above finite element model is as follows:

[0088] Using the mechanical parameters of the specimen, the borehole parameters, and the explosive parameters inside the borehole as input parameters, a three-dimensional mechanical model consistent with the actual borehole blasting scenario is constructed. The model coverage area (including the borehole area and the area affected by cracks around the borehole) is clearly defined, and the mechanical parameters of the specimen, including compressive strength, tensile strength, and elastic modulus, are accurately entered to ensure that the characteristics of the model specimen and the geometry of the borehole are completely matched with the actual situation on site, laying the foundation for subsequent blasting simulation.

[0089] Blasting loads are applied according to the blasting construction process to simulate the instantaneous impact and pressure transmission process generated by the explosion of explosives; boundary conditions are set for the model: horizontal displacement constraints are applied in the horizontal direction to simulate the constraint effect of the surrounding rock mass; fixed constraints are applied at the bottom vertically to simulate the support effect of the deep rock mass; at the same time, the contact relationship between the explosive and the borehole wall, and between the borehole wall and the rock mass are defined to simulate the interaction and force transmission characteristics.

[0090] Using the aforementioned mechanical parameters, borehole parameters, and explosive parameters as inputs, and combining them with the blasting energy transfer mechanism, modules related to explosion pressure diffusion, rock stress and strain calculation, and blasting disturbance analysis are embedded in the model. A quantitative correlation is established between explosive parameters, rock mechanical parameters, and pressure distribution around the borehole, thereby simulating the blasting impact and rock pressure response, and finally completing the finite element model construction.

[0091] Based on the above, it should be noted that:

[0092] The explosion pressure diffusion module, rock mass stress and strain calculation module, and blasting disturbance analysis module all adopt existing mature numerical simulation modules in this field. They are embedded into the above finite element model through parameter adaptation and combination to realize the simulation calculation of explosion pressure transmission, rock mass stress solution, and blasting disturbance effect. This method only makes adaptive calls and parameter settings to the above modules and does not involve any improvement to the module program itself.

[0093] The explosion pressure diffusion module simulates the dynamic propagation and diffusion process of the explosion pressure in the borehole and the surrounding rock mass after the explosion. This module combines the collected explosive parameters and borehole parameters to calculate the change law of explosion pressure with time and spatial location in real time, and restores the real process of pressure gradually spreading and attenuating from the center of the borehole to the surrounding rock mass.

[0094] The rock mass stress-strain calculation module is based on the pressure data output by the explosion pressure dynamic diffusion module, combined with the mechanical parameters of the sample, to calculate the stress and strain values ​​at various coordinate points of the rock mass around the borehole at different times.

[0095] The blasting disturbance analysis module simulates the disturbance effect of the instantaneous impact load generated by an explosive explosion on the surrounding rock mass. This module combines the blasting energy transfer mechanism to recreate the instantaneous effect of the explosion impact on the rock mass, considers the changes in the stress characteristics of the rock mass under impact load, and corrects the stress and strain calculation results.

[0096] Based on the above embodiments, the preset time period refers to the time range set in advance, starting from the moment of blasting, for fully capturing the dynamic changes of the explosion pressure around the blast hole. Its core purpose is to cover the entire process of pressure generation, diffusion, decay to stabilization after the explosion of the explosive, ensuring that pressure data at each coordinate point at different times can be fully collected.

[0097] The actual working conditions of similar blasting projects were investigated on-site, and the duration of pressure from generation and diffusion to complete decay and stabilization after the explosion of explosives in similar projects was collected as a preset time period.

[0098] Based on the above embodiments, taking the blasting moment as the starting point, the pressure values ​​of each coordinate point in the area surrounding the blast hole are obtained at each moment within a preset time period. The specific logic is as follows:

[0099] The blasting simulation start time after the finite element model is completed is taken as the blasting time to ensure that this time is consistent with the actual time node of the borehole blasting, thus laying an accurate time reference for the subsequent time series acquisition of pressure values.

[0100] After starting the finite element simulation, relying on the explosion pressure diffusion module embedded in the finite element model, the pressure changes of all coordinate points in the area around the borehole are captured in real time, and the pressure value of each coordinate point at each moment in the preset time period is accurately recorded according to the preset time interval.

[0101] The time interval is set based on the explosive pressure diffusion rate, the dynamic characteristics of crack initiation and propagation, and the simulation accuracy requirements, and its value ranges from 10. -6 seconds ~ 10 - ³ seconds;

[0102] The system simultaneously organizes and stores the pressure values ​​collected at each time point and coordinate point, clearly defining the coordinate location and time information corresponding to each pressure value, and forming a "coordinate-time-pressure value" correspondence.

[0103] Based on the above, it should be noted that:

[0104] By performing finite element simulation of the blasting process in the area surrounding the blast hole, starting from the blasting moment, the pressure values ​​of each coordinate point in the area surrounding the blast hole at each moment within a preset time period are obtained, thus realizing the binding of the explosion pressure data with each coordinate point, and thereby establishing the spatial-mechanical relationship between explosion pressure and crack propagation.

[0105] By precisely binding the explosion pressure data with each coordinate point, the explosion pressure distribution characteristics at different spatial locations are clearly presented, realizing a one-to-one correspondence between the explosion pressure data and spatial location, ensuring that the pressure data can accurately reflect the stress state of different areas around the borehole; by establishing a spatial-mechanical correlation between explosion pressure and crack propagation, the pressure data can directly provide support for the inversion of the crack propagation process.

[0106] S3. Based on the mechanical parameters of the sample and the internal stress state of each coordinate point in the area around the blast hole during blasting, construct a pressure-stress conversion model, input the pressure value, obtain the internal equivalent stress value of each coordinate point at each moment within a preset time period, determine the area to which each coordinate point belongs based on the distance between each coordinate point and the blast hole, and assign the corresponding stress reduction coefficient. Based on the stress reduction coefficient, obtain the corrected value of the internal equivalent stress of each coordinate point at each moment.

[0107] Based on the above embodiments, a pressure-stress conversion model is constructed according to the mechanical parameters of the sample and the internal stress state of each coordinate point in the area around the blast hole during blasting. The specific logic is as follows:

[0108] If the internal stress state of a coordinate point at a certain moment is under tension, the tensile strength of the coordinate point at this moment is calculated by the ratio of the elastic modulus to the tensile stress proportionality coefficient. The tensile stress proportionality coefficient is then used as the adaptive proportionality coefficient of the coordinate point at this moment.

[0109] If the internal stress state of a coordinate point at a certain moment is under compression, the compressive strength of the coordinate point at this moment is calculated by the ratio of the elastic modulus to the compressive stress proportionality coefficient. The compressive stress proportionality coefficient is then used as the adaptive proportionality coefficient of the coordinate point at this moment.

[0110] Based on the above, it should be noted that:

[0111] Tensile strength is the maximum tensile force that a specimen can withstand, while elastic modulus is the ability of a specimen to resist deformation when under tension. The ratio of the two is the matching relationship between "the maximum tensile force that the specimen can withstand" and "its ability to resist tensile deformation". This ratio can accurately convert the explosive pressure into the tensile stress value inside the specimen.

[0112] Similarly, compressive strength is the maximum pressure limit that a specimen can withstand, and elastic modulus is the ability of a specimen to resist deformation when under pressure. The ratio of the two is the matching relationship between "the maximum pressure value that a specimen can withstand" and "its ability to resist compressive deformation", which is used to convert the explosive pressure into the compressive stress value inside the specimen.

[0113] The expression for the pressure-stress conversion model is as follows:

[0114] The internal equivalent stress value is equal to the product of the adaptive proportional coefficient and the pressure value;

[0115] If the adaptive scaling factor is the tensile stress scaling factor, then the internal equivalent stress value is the internal tensile stress value.

[0116] If the adaptive scaling factor is the compressive stress scaling factor, then the internal equivalent stress value is the internal compressive stress value.

[0117] Based on the above, it should be noted that:

[0118] The adaptive scaling factor is either the tensile stress scaling factor or the compressive stress scaling factor. This factor acts as a "transformation bridge." The explosion pressure is an externally applied force, which cannot be directly used to calculate the internal stress. By multiplying the adaptive scaling factor by the externally applied pressure value, the actual internal stress at each coordinate point can be obtained.

[0119] Based on the above embodiments, the region to which each coordinate point belongs is determined according to the distance between each coordinate point and the borehole, and a corresponding stress reduction factor is assigned, as follows:

[0120] like Figure 2 As shown, based on the distance between each coordinate point and the borehole, the area around the borehole is divided into the near-core area, the stress attenuation transition area, and the far-field diffusion area.

[0121] If the distance between a coordinate point and the borehole Greater than or equal to 0 and less than 3 times the borehole diameter The coordinate point belongs to the near-core area of ​​the borehole, and the stress reduction factor assigned to this coordinate point is 1.0;

[0122] If the distance between a coordinate point and the borehole Greater than or equal to 3 times the borehole diameter And less than 10 times the borehole diameter The coordinate point belongs to the stress attenuation transition zone, and the stress reduction factor assigned to the coordinate point is 0.8;

[0123] If the distance between a coordinate point and the borehole ≥10 times the borehole diameter The coordinate point belongs to the far-field diffusion region, and the stress reduction factor assigned to this coordinate point is 0.6;

[0124] Based on the distance between each coordinate point and the borehole, the corresponding area is determined, and then the stress reduction coefficient corresponding to that coordinate point is obtained.

[0125] Based on the above, it should be noted that:

[0126] Based on the propagation law of blast wave in borehole blasting, indoor rock dynamics tests, and field engineering measurement experience, 3 times the borehole diameter This is the characteristic critical distance for the direct action of ultra-high pressure detonation waves. Within the range of 0 to 3 times the borehole diameter, the rock mass is subjected to ultra-high pressure loads from the explosion, with extremely high stress levels and no significant attenuation, exhibiting a strong direct impact. Beyond 3 times the borehole diameter... Subsequently, the explosive stress dissipates rapidly due to the plastic deformation of the rock mass and the initiation and expansion of internal microcracks, gradually entering a stage of gradual stress attenuation. This boundary can serve as a key proximity control point characterizing the near-core area.

[0127] 10 times the borehole diameter It is a global boundary threshold determined based on the nonlinear attenuation characteristics of explosive stress in rock mass and the statistical laws of rock mass damage and failure engineering. At 3 times the borehole diameter... ~10 times the borehole diameter Within the range, the explosive stress dissipates rapidly and gradually tends to stabilize; when the distance is greater than 10 times the borehole diameter... Subsequently, the strong impact stress significantly decreased and could no longer dominate the macroscopic damage effect of the rock mass. The rock mass response entered the far-field stress diffusion stage. Therefore, a borehole diameter of 10 times... This can serve as the critical point defining the stress attenuation transition zone and the far-field diffusion zone. The near-core region of the borehole is the main control area for the direct coupling effect of the detonation wave. In this region, the stress wave propagation path is short, and the rock mass does not have enough time to dissipate the explosion energy through plastic deformation and fracture development. Dynamic experiments and field monitoring show that a distance of 3 times the borehole diameter from the borehole wall... Within this range, the peak stress is close to the ultimate detonation pressure, and the stress attenuation effect is negligible. To accurately reproduce the true high-stress state of the core area and ensure the accuracy of the criteria for rock mass crack initiation and propagation, the stress reduction factor for this area is set to 1.0, meaning that all original stresses are retained without stress reduction correction.

[0128] Within the stress attenuation transition zone, the powerful shock wave from the explosion transforms into a propagating stress wave. The explosion energy is significantly lost through rock mass plastic rheology, the initiation and propagation of new fractures, and wave field scattering. Extensive blasting test data indicates that the distance from the borehole diameter to the rock mass is affected by the stress at which the energy is significantly reduced. Increase to 10 times the borehole diameter During the process, the stress attenuation of the rock mass during the explosion was approximately 20%. To objectively characterize the absorption and dissipation effect of the rock mass on the explosion energy, engineering and numerical calculations generally adopt an 80% original stress retention ratio, with a corresponding stress reduction factor of 0.8.

[0129] In the far-field diffusion zone, when the propagation distance exceeds 10 times the borehole diameter... Subsequently, the strong impact load from the explosion completely attenuated into a low-frequency elastic stress wave, and the damaging effect of residual stress on the rock mass was essentially eliminated. To avoid redundancy of large-scale low-stress invalid data and to prevent mechanical distortion caused by excessive reduction of far-field stress, a stable and universally applicable normalized reduction parameter needs to be selected. Combining multiple sets of field blasting tests and stress inversion fitting results, a stress reduction factor of 0.6 can suppress the problem of abnormally high far-field stress while effectively preserving the basic trend of stress evolution across the entire domain, thus meeting the requirements for characterizing the far-field rock mass mechanical response.

[0130] By dividing the stress field around the borehole into gradient zones based on radial multiples and matching stress reduction coefficients decreasing progressively to 1.0, 0.8, and 0.6, the layered quantitative correction and precise characterization of explosive stress from the near-core region, stress attenuation region to far-field diffusion region were achieved.

[0131] Based on the above embodiments, the internal equivalent stress correction value of each coordinate point at each time is obtained according to the stress reduction factor. The specific logic is as follows:

[0132] For the distance between each coordinate point and the borehole, extract the corresponding stress reduction factor;

[0133] Multiply the internal equivalent stress value of each coordinate point at each time point by the corresponding stress reduction factor to obtain the corrected internal equivalent stress value of each coordinate point at each time point.

[0134] Based on the above, it should be noted that:

[0135] Based on the mechanical parameters of the specimen and the internal stress state during borehole blasting, a pressure-stress conversion model is constructed to obtain the internal equivalent stress value of each coordinate point at each moment within a preset time period. Then, based on the distance between each coordinate point and the borehole, the corresponding stress reduction coefficient is determined, and the internal equivalent stress value is specifically corrected to obtain the corrected internal equivalent stress value. This accurately matches the objective law of the radial attenuation of explosive stress along the borehole during borehole blasting. During borehole blasting, the stress generated by the explosive explosion will be transmitted radially to the surrounding rock mass with the borehole as the center. The closer to the borehole, the more concentrated and stronger the stress is. The farther away from the borehole, the more the stress will gradually decrease due to the damping effect of the rock mass. This is the core characteristic of the stress distribution during borehole blasting.

[0136] By correcting the stress reduction factor based on distance correlation, the traditional conversion model is able to overcome the limitation of ignoring the radial stress attenuation characteristics, and the corrected internal equivalent stress value can truly reflect the actual stress state of the rock mass at different locations.

[0137] Meanwhile, the obtained internal equivalent stress correction value serves as the core basic data. On the one hand, it provides accurate stress basis for determining the crack initiation time. By comparing it with the preset stress threshold, the timing of crack initiation at each coordinate point can be accurately identified. On the other hand, it provides data support for crack location determination and crack propagation process inversion.

[0138] S4. Compare the internal equivalent stress correction value of each coordinate point at each time with the preset stress threshold to obtain the crack initiation time of each coordinate point, and regard this coordinate point as the crack initiation coordinate point at this time.

[0139] Based on the above embodiments, the internal equivalent stress correction value of each coordinate point at each time moment is compared with the preset stress threshold to obtain the crack initiation time of each coordinate point. The specific logic is as follows:

[0140] For any coordinate point, the moment when its internal equivalent stress correction value first rises from less than the stress threshold to equal to or greater than the stress threshold is extracted. This moment is defined as the crack initiation moment of this coordinate point, that is, this coordinate point is regarded as the crack initiation coordinate point at this moment.

[0141] Among them, the stress threshold is the maximum stress that the area around the borehole can withstand when the crack just begins to appear.

[0142] The specific expression for the stress threshold and the basis for its setting are as follows:

[0143] The stress threshold is the product of the tensile strength of the specimen and the correction factor. The above expression is used to set the stress threshold for the following reasons:

[0144] During the blasting process, rock mass cracking is mainly controlled by tensile stress. The tensile strength of the sample reflects the maximum tensile stress that the rock mass can withstand. Based on this, the conditions for rock mass crack initiation can be accurately determined.

[0145] Since tensile strength is a strength index measured under static loading conditions, while blasting is a dynamic impact load, the actual crack resistance of rock mass under impact is lower than its static performance. Therefore, a correction factor is introduced to correct the static tensile strength so that the stress threshold is more in line with the dynamic working conditions of blasting.

[0146] The correction factor is selected based on the actual blasting conditions: the larger the charge and the higher the explosion pressure, the closer the correction factor is to 0.9; the borehole diameter... The larger the value, the closer the correction factor is to 0.7, so as to ensure that the stress threshold can truly reflect the crack resistance of the rock mass under impact load.

[0147] S5. For any crack initiation coordinate point, extract its associated coordinate points within its associated time window, and connect the crack initiation coordinate points and associated coordinate points extracted at all times within a preset time period to obtain the crack propagation process in the area surrounding the borehole.

[0148] Based on the above embodiments, for any crack initiation coordinate point, its associated coordinate points are extracted within its associated time window. The specific logic is as follows:

[0149] like Figure 3 As shown, starting from the moment of detonation, for any moment within a preset time period, the associated time window for that moment is determined, and the associated time window is located before that moment.

[0150] The length of the associated time window is set based on the propagation velocity of the blast stress wave, the crack initiation response rate, and the simulation time accuracy, and its value ranges from 1×10⁻⁶. -4 s~5×10 - ³s;

[0151] If the moment is the moment of explosion, the coordinate point of crack initiation at that moment is not the extension point;

[0152] If the time interval between the blasting moment and that moment is less than the length of the associated time window, then the time interval between the blasting moment and that moment is taken as the associated time window for that moment.

[0153] For all other moments, a fixed-length time interval is taken forward from the current moment as the endpoint to form the associated time window;

[0154] For any crack initiation coordinate point extracted at this moment, the distance between it and each crack initiation coordinate point in the associated time window is calculated one by one. Crack initiation coordinate points in the associated time window whose distance from this crack initiation coordinate point is less than a preset threshold are extracted and used as associated coordinate points of this crack initiation coordinate point.

[0155] If there are no associated coordinate points, then the coordinate point where the crack initiation occurs will not be used as the extension point.

[0156] If there is only one associated coordinate point, then the coordinate point where the crack initiation occurs shall be taken as the extension point of the associated coordinate point.

[0157] Among them: the first extension point Coordinates of the first crack initiation point The extension point; the second extension point As the first extension point The subsequent extension point; the third extension point For the second extension point The subsequent extension point; the fourth extension point Coordinates of the second crack initiation point The extension point;

[0158] If there is more than one associated coordinate point, the associated coordinate point with the smallest distance from the crack initiation coordinate point is selected as the preferred coordinate point, and the crack initiation coordinate point is used as the extension point of the preferred coordinate point.

[0159] If there is more than one preferred coordinate point, including the first preferred coordinate point Second preferred coordinate point Then, the priority of each preferred coordinate point is extracted one by one, and a preferred coordinate point with a priority no lower than that of the crack initiation coordinate point is selected as the preceding coordinate point.

[0160] If there is only one preceding coordinate point, take the crack initiation coordinate point as the extension point of the preceding coordinate point.

[0161] If there is more than one preceding coordinate point, for any preceding coordinate point, based on the correspondence of the extension points, determine the crack curve segment where the preceding coordinate point is located, calculate the average curvature of each crack curve segment, connect each crack curve segment with the crack initiation coordinate point to obtain each complete crack curve, and calculate the average curvature of each complete crack curve.

[0162] Assign priority values ​​to the coordinate points in the area surrounding the borehole, as follows:

[0163] When a coordinate point is located in the core area of ​​the borehole, this area is closest to the borehole, has the strongest explosive load, the largest stress amplitude, and is the core area where cracks preferentially initiate and dominate propagation. It has the strongest control over the overall direction of the crack, so its priority is assigned to 3.

[0164] When a coordinate point is located in the stress attenuation transition zone, the stress level in this area is significantly lower than that in the core area. The crack propagation is less directly affected by the explosive load and is more manifested as secondary propagation induced by stress wave reflection and superposition. Its ability to control the direction of the main crack is weaker than that in the core area. Therefore, its priority is assigned to 2.

[0165] When a coordinate point is located in the far-field diffusion region, this region is farthest from the borehole, the stress has been greatly attenuated, the control effect of the explosive load on crack propagation is the weakest, the cracks are mostly tailing and extending, and have the least impact on the overall crack morphology, then its priority is assigned to 1.

[0166] Calculate the absolute change in average curvature between each crack curve segment and the complete crack curve, and calculate the difference in priority between each preceding coordinate point and the crack initiation coordinate point.

[0167] Based on the above, it should be noted that:

[0168] The preset threshold is determined comprehensively based on the crack propagation characteristics of deep-hole blasting rock mass, the diameter of the blast hole, and the degree of rock mass fragmentation. Specifically, the preset distance threshold is based on the diameter of the blast hole, and the value is 0.1 to 0.5 times the diameter of the blast hole.

[0169] The preset threshold is used to determine whether each crack initiation coordinate point within the associated time window belongs to the associated coordinate points of the extracted crack initiation coordinate points:

[0170] If the distance between the coordinate point of crack initiation and the coordinate point of crack initiation within the associated time window is less than a preset threshold, then the two are considered to be close in spatial position, and the coordinate point of crack initiation can be used as the associated coordinate point of this crack initiation.

[0171] If the distance between the coordinate point of crack initiation and the coordinate point of crack initiation within the associated time window is not less than a preset threshold, then the two are considered to be spatially distant, and the coordinate point of crack initiation cannot be used as the associated coordinate point of this crack initiation.

[0172] For any preceding coordinate point, based on the correspondence of the extended points, determine the superior node of that preceding coordinate point, specifically as follows:

[0173] For any crack initiation coordinate point, if it is an extension point of another crack initiation coordinate point, then it is regarded as a subordinate node of the other crack initiation coordinate point, that is, the other crack initiation coordinate point is regarded as its superior node. For any preceding coordinate point, the superior node of the preceding coordinate point is extracted, and this relationship is used to trace upwards level by level to obtain its superior nodes in a loop until the number of superior nodes reaches the preset number threshold, or no new superior nodes exist.

[0174] The preset number threshold is the maximum number of subordinate nodes, with a value range of 3 to 8 layers, and a preferred value of 5 layers.

[0175] Specifically, for any crack curve segment or complete crack curve, the coordinate points arranged sequentially on the curve are traversed, and for each set of three consecutive coordinate points, the curvature of the corresponding local curve segment is calculated; all local curvatures are summed and divided by the number of local curve segments to obtain the average curvature of the crack curve.

[0176] Based on the above embodiments, the difference between the absolute change in normalized average curvature and the priority is weighted and calculated to obtain the comprehensive evaluation coefficient of each crack integrity curve, according to the following formula:

[0177]

[0178] in, The comprehensive evaluation coefficient is used to combine two index parameters: the absolute change in normalized average curvature and the difference in priority, to comprehensively evaluate the crack completion curve formed by connecting each preceding coordinate point with the crack initiation coordinate point, and to judge the smoothness of the crack completion curve and the spatial correlation between the preceding coordinate point and the crack initiation coordinate point.

[0179] In the formula, This represents the absolute change in the mean curvature. This represents the difference in priority.

[0180] Based on the above, it should be noted that:

[0181] The absolute change in average curvature is the absolute value of the difference between the average curvature of the complete crack curve and the average curvature of the crack curve segment. It reflects the change in the degree of crack bending after a new point is reached. The smaller the value, the smoother and more continuous the crack curve is.

[0182] The difference in priority is the difference between the priority of the crack initiation coordinate point and the priority of the preceding coordinate point. It reflects the difference in spatial importance between the two points in the blasting stress field. The smaller the value, the stronger the spatial correlation between the two points and the more consistent the expansion logic.

[0183] Therefore, the comprehensive evaluation coefficient is positively correlated with the difference between the absolute change in the average curvature and the priority. The smaller the comprehensive evaluation coefficient, the higher the smoothness of the crack curve, the stronger the spatial correlation, and the more reasonable the corresponding crack propagation path.

[0184] The absolute change in average curvature characterizes the geometric shape of the curve, while the priority difference characterizes the spatial correlation of the blasting stress field. The two are independent of each other and have no obvious coupling relationship. Using linear weighting can objectively reflect the combined influence of the two indicators on the rationality of crack propagation.

[0185] In the formula, The weighting coefficient is the absolute change in the mean curvature. The weighting coefficients for the differences in priority;

[0186] The priority is determined by the stress field region of the borehole, which directly reflects the dominant control of the explosive load on crack initiation and propagation. It is the core physical indicator reflecting the rationality of crack propagation, and therefore it is given higher weight.

[0187] The absolute change in average curvature only characterizes the geometric smoothness of the crack curve. It is a morphological constraint auxiliary indicator and does not directly reflect the inherent law of blast stress driving. Its influence on the rationality of crack propagation path is lower than its priority, so its weight is relatively small.

[0188] Therefore, in On this basis, let ;

[0189] As one implementation method, The value range is an open interval between 0 and 0.5. The value range is an open interval of 0.5-1.0. The specific value is set by technical personnel according to the actual situation and is not restricted here.

[0190] Based on the above formula, the comprehensive evaluation coefficient of all crack completion curves is calculated. The preceding coordinate point corresponding to the minimum comprehensive evaluation coefficient is taken as the target coordinate point, and the crack initiation coordinate point is taken as the extension point of the target coordinate point.

[0191] Please see Figure 4 The present invention also provides a technical solution:

[0192] The data acquisition module is used to select samples in the area around the blast hole for mechanical loading tests. Based on the load and deformation parameters collected during the test, the mechanical parameters of the samples are calculated. At the same time, the blast hole parameters before blasting and the explosive parameters inside the blast hole are collected.

[0193] The data simulation module is used to perform finite element simulation of the blasting process in the area around the blast hole using the mechanical parameters of the sample, the parameters of the borehole, and the parameters of the explosive in the borehole as input parameters. Starting from the blasting time, it obtains the pressure values ​​of each coordinate point in the area around the borehole at each time within a preset time period.

[0194] The data correction module is used to construct a pressure-stress conversion model based on the mechanical parameters of the sample and the internal stress state of each coordinate point in the area around the blast hole during blasting. By inputting the pressure value, the internal equivalent stress value of each coordinate point at each moment within a preset time period is obtained. Based on the distance between each coordinate point and the blast hole, the region to which each coordinate point belongs is determined, and the corresponding stress reduction coefficient is assigned. Based on the stress reduction coefficient, the internal equivalent stress correction value of each coordinate point at each moment is obtained.

[0195] The comparison module is used to compare the internal equivalent stress correction value of each coordinate point at each time with the preset stress threshold to obtain the crack initiation time of each coordinate point, and at that time, this coordinate point is regarded as the crack initiation coordinate point.

[0196] The process inversion module is used to extract the associated coordinates of any crack initiation coordinate point within its associated time window, and to sequentially connect the crack initiation coordinates and associated coordinates extracted at all times within a preset time period to obtain the crack propagation process in the area surrounding the borehole.

[0197] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0198] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by software, electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0199] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0200] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole, characterized in that, The specific steps include: S1. Select specimens in the area around the borehole for mechanical loading tests. Calculate the mechanical parameters of the specimens based on the load and deformation parameters collected during the test. At the same time, collect the borehole parameters before blasting and the explosive parameters inside the borehole. S2. Using the mechanical parameters of the sample, the borehole parameters, and the explosive parameters inside the borehole as input parameters, a finite element simulation of the blasting process in the area surrounding the borehole is performed. Starting from the blasting time, the pressure values ​​of each coordinate point in the area surrounding the borehole at each time within a preset time period are obtained. S3. Based on the mechanical parameters of the sample and the internal stress state of each coordinate point in the area around the blast hole during blasting, construct a pressure-stress conversion model, input the pressure value, obtain the internal equivalent stress value of each coordinate point at each moment within a preset time period, determine the area to which each coordinate point belongs based on the distance between each coordinate point and the blast hole, and assign the corresponding stress reduction coefficient. Based on the stress reduction coefficient, obtain the corrected value of the internal equivalent stress of each coordinate point at each moment. S4. Compare the internal equivalent stress correction value of each coordinate point at each time with the preset stress threshold to obtain the crack initiation time of each coordinate point, and regard this coordinate point as the crack initiation coordinate point at this time. S5. For any crack initiation coordinate point, extract its associated coordinate points within its associated time window, and connect the crack initiation coordinate points and associated coordinate points extracted at all times within a preset time period to obtain the crack propagation process in the area surrounding the borehole.

2. The method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole according to claim 1, characterized in that, The load and deformation parameters include axial load, displacement, and strain; the mechanical parameters include compressive strength, tensile strength, and elastic modulus; the borehole parameters include borehole diameter and depth; and the explosive parameters include detonation pressure, detonation velocity, and charge amount of the explosive in the borehole.

3. The method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole according to claim 2, characterized in that, Based on the mechanical parameters of the specimen and the internal stress state of each coordinate point in the area around the blast hole during blasting, a pressure-stress conversion model is constructed, with the specific logic as follows: If the internal stress state of a coordinate point at a certain moment is under tension, the tensile strength of the coordinate point at this moment is calculated by the ratio of the elastic modulus to the tensile stress proportionality coefficient. The tensile stress proportionality coefficient is then used as the adaptive proportionality coefficient of the coordinate point at this moment. If the internal stress state of a coordinate point at a certain moment is under compression, the compressive strength of the coordinate point at this moment is calculated by the ratio of the elastic modulus to the compressive stress proportionality coefficient. The compressive stress proportionality coefficient is then used as the adaptive proportionality coefficient of the coordinate point at this moment. The expression for the pressure-stress conversion model is: the internal equivalent stress value is equal to the product of the adaptive scaling factor and the pressure value; If the adaptive scaling factor is the tensile stress scaling factor, then the internal equivalent stress value is the internal tensile stress value. If the adaptive scaling factor is the compressive stress scaling factor, then the internal equivalent stress value is the internal compressive stress value.

4. The method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole according to claim 1, characterized in that, Based on the distance between each coordinate point and the borehole, the region to which that coordinate point belongs is determined, and the corresponding stress reduction factor is assigned. The specific logic is as follows: Based on the distance between each coordinate point and the borehole, the area around the borehole is divided into the near-core area, the stress attenuation transition area, and the far-field diffusion area. If the distance between a coordinate point and the borehole Greater than or equal to 0 and less than 3 times the borehole diameter The coordinate point belongs to the near-core area of ​​the borehole, and the stress reduction factor assigned to this coordinate point is 1.0; If the distance between a coordinate point and the borehole Greater than or equal to 3 times the borehole diameter And less than 10 times the borehole diameter The coordinate point belongs to the stress attenuation transition zone, and the stress reduction factor assigned to the coordinate point is 0.8; If the distance between a coordinate point and the borehole ≥10 times the borehole diameter The coordinate point belongs to the far-field diffusion region, and the stress reduction factor assigned to this coordinate point is 0.6; Based on the distance between each coordinate point and the borehole, the corresponding area is determined, and then the stress reduction coefficient corresponding to that coordinate point is obtained.

5. The method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole according to claim 4, characterized in that, The internal equivalent stress correction value at each coordinate point at each time is obtained based on the stress reduction factor. The specific logic is as follows: For the distance between each coordinate point and the borehole, extract the corresponding stress reduction factor; Multiply the internal equivalent stress value of each coordinate point at each time point by the corresponding stress reduction factor to obtain the corrected internal equivalent stress value of each coordinate point at each time point.

6. The method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole according to claim 5, characterized in that, The crack initiation time at each coordinate point is obtained by comparing the internal equivalent stress correction value at each time point with the preset stress threshold. The specific logic is as follows: For any coordinate point, the moment when its internal equivalent stress correction value first rises from less than the stress threshold to equal to or greater than the stress threshold is extracted. This moment is defined as the crack initiation moment of this coordinate point, that is, this coordinate point is regarded as the crack initiation coordinate point at this moment.

7. The method for measuring the explosion pressure and crack propagation process around a deep-hole blasting borehole according to claim 6, characterized in that, For any crack initiation coordinate point, extract its associated coordinate points within its associated time window. The specific logic is as follows: Starting from the moment of detonation, for any moment within a preset time period, the associated time window for that moment is determined; For any crack initiation coordinate point extracted at this moment, the distance between it and each crack initiation coordinate point in the associated time window is calculated one by one. Crack initiation coordinate points in the associated time window whose distance from this crack initiation coordinate point is less than a preset threshold are extracted and used as associated coordinate points of this crack initiation coordinate point. If there are no associated coordinate points, then the coordinate point where the crack initiation occurs will not be used as the extension point. If there is only one associated coordinate point, then the coordinate point where the crack initiation occurs shall be taken as the extension point of the associated coordinate point. If there is more than one associated coordinate point, the associated coordinate point with the smallest distance from the crack initiation coordinate point is selected as the preferred coordinate point, and the crack initiation coordinate point is used as the extension point of the preferred coordinate point. If there is more than one preferred coordinate point, the priority of each preferred coordinate point is extracted one by one, and a preferred coordinate point with a priority no lower than that of the crack initiation coordinate point is selected as the preceding coordinate point. If there is only one preceding coordinate point, take the crack initiation coordinate point as the extension point of the preceding coordinate point. If there is more than one preceding coordinate point, for any preceding coordinate point, based on the correspondence of the extension points, determine the crack curve segment where the preceding coordinate point is located, calculate the average curvature of each crack curve segment, connect each crack curve segment with the crack initiation coordinate point to obtain each complete crack curve, and calculate the average curvature of each complete crack curve. Assign priority values ​​to the coordinate points in the area surrounding the borehole, as follows: If a coordinate point is located near the core area of ​​the borehole, its priority is assigned a value of 3; When a coordinate point is located in the stress attenuation transition zone, its priority is assigned a value of 2; If a coordinate point is located in the far-field diffusion region, its priority is assigned to 1; Calculate the absolute change in average curvature between each crack curve segment and the complete crack curve, calculate the difference in priority between each preceding coordinate point and the crack initiation coordinate point, and weight the difference in normalized average curvature and priority to obtain the comprehensive evaluation coefficient of each complete crack curve. The preceding coordinate point corresponding to the minimum comprehensive evaluation coefficient is taken as the target coordinate point, and the crack initiation coordinate point is taken as the extension point of the target coordinate point.

8. A measurement system for the explosion pressure and crack propagation process around a deep-hole blasting borehole, the system being used to perform the measurement method for the explosion pressure and crack propagation process around a deep-hole blasting borehole as described in any one of claims 1-7, characterized in that, include: The data acquisition module is used to select samples in the area around the blast hole for mechanical loading tests. Based on the load and deformation parameters collected during the test, the mechanical parameters of the samples are calculated. At the same time, the blast hole parameters before blasting and the explosive parameters inside the blast hole are collected. The data simulation module is used to perform finite element simulation of the blasting process in the area around the blast hole using the mechanical parameters of the sample, the parameters of the borehole, and the parameters of the explosive in the borehole as input parameters. Starting from the blasting time, it obtains the pressure values ​​of each coordinate point in the area around the borehole at each time within a preset time period. The data correction module is used to construct a pressure-stress conversion model based on the mechanical parameters of the sample and the internal stress state of each coordinate point in the area around the blast hole during blasting. By inputting the pressure value, the internal equivalent stress value of each coordinate point at each moment within a preset time period is obtained. Based on the distance between each coordinate point and the blast hole, the region to which each coordinate point belongs is determined, and the corresponding stress reduction coefficient is assigned. Based on the stress reduction coefficient, the internal equivalent stress correction value of each coordinate point at each moment is obtained. The comparison module is used to compare the internal equivalent stress correction value of each coordinate point at each time with the preset stress threshold to obtain the crack initiation time of each coordinate point, and at that time, this coordinate point is regarded as the crack initiation coordinate point. The process inversion module is used to extract the associated coordinates of any crack initiation coordinate point within its associated time window, and to sequentially connect the crack initiation coordinates and associated coordinates extracted at all times within a preset time period to obtain the crack propagation process in the area surrounding the borehole.

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