A Multi-Field Test Method for Dynamic Mechanical Response of Surrounding Rock-Ore Body Combination During Blasting

Abstract

This invention provides a multi-field testing method for the dynamic mechanical response of a rock-orebody composite under blasting, belonging to the field of rock mechanics performance testing technology. The method involves casting similar materials for the surrounding rock and orebody within a transparent constrained mold, and pre-embedding a three-level nested telescopic blast hole mold to prefabricate an adjustable-volume charge cavity inside the composite specimen. After demolding the composite specimen and spraying speckle patterns, it is reinserted into the constrained mold to form passive confining pressure. An acoustic velocimeter, vibration acceleration sensor, and image monitoring system are deployed. A blasting loading source is placed into the charge cavity and detonated, simultaneously acquiring vibration waveforms and surface sequence digital images. The changes in wave velocity before and after loading are compared to quantify internal damage. Combined with vibration parameters and surface displacement field data, the dynamic mechanical properties of the composite material are comprehensively evaluated, thus providing precise quantitative data on blasting charge quantity for geotechnical engineering blasting model tests. This invention achieves multi-field, synchronous, and accurate testing of the dynamic mechanical properties of model materials under blasting.

Description

Technical Field

[0001] This invention belongs to the field of rock mechanical property testing technology, and more specifically, it relates to a multi-field testing method for the dynamic mechanical response of blasting of a surrounding rock-ore body combination. Background Technology

[0002] In indoor similarity model testing of drill-and-blast mining in deep hard rock deposits, existing technologies have the following problems: First, existing technologies cannot prefabricate loading cavities with variable equivalent and variable tilt angles inside the test specimen, resulting in fixed energy levels and directions of action of the blasting loading source, making it impossible to conduct systematic comparative tests for different blasting conditions.

[0003] Second, existing testing methods can only obtain single physical quantities such as vibration acceleration or macroscopic cracks on the surface after the explosion. They lack the ability to simultaneously collect multi-physics information such as internal damage, vibration response and surface deformation field of the specimen during the explosion loading process, making it difficult to fully reveal the damage evolution law of the model material under explosion load.

[0004] Third, existing technologies lack the means to quantitatively compare the internal damage of specimens before and after explosive loading, and cannot quantitatively evaluate the invisible internal damage of specimens through indicators such as changes in wave velocity field. The test conclusions rely on apparent observations and are therefore unreliable. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-field testing method for the dynamic mechanical response of blasting in a rock-ore body combination, aiming to solve the technical problems of insufficient reliability of test results in existing blasting similar model tests, such as the inability to adjust the loading source, the limited test information, and the lack of internal damage quantification methods.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a multi-field testing method for the dynamic mechanical response of a surrounding rock-ore body combination during blasting, comprising the following steps: S100. Within the transparent constraint mold, similar materials for the surrounding rock and similar materials for the ore body are poured sequentially. During the pouring of the similar materials for the ore body, a three-level nested telescopic blast hole mold is pre-embedded. After the similar materials for the ore body harden, the mold is removed to form an adjustable charge chamber in the area of ​​the similar materials for the ore body. S200. Spray speckle coating onto the surface of the demolded composite specimen and place it back into the constraint mold. Use the rigid wall of the constraint mold to form a passive confining constraint on the composite specimen. Use an acoustic velocimeter to measure the wave velocity in sections on the surface of the composite specimen and record it as the initial wave velocity field. Fix a vibration acceleration sensor on the outer wall of the constraint mold and set up an image monitoring system to align with the observation surface of the composite specimen. S300. Place the explosive loading source of the set equivalent into the charging cavity and fill it. At the same time, start the vibration acceleration sensor and the image monitoring system, and then detonate the loading source. Collect the vibration waveform signal and the sequence of digital images of the surface of the composite specimen in real time during the entire explosive loading process. S400. After loading, the surface damage characteristics of the composite specimen are measured and recorded. The wave velocity field after loading is obtained again using the sonic velocimeter. By comparing the changes in wave velocity before and after loading, the internal damage distribution of the composite specimen is quantitatively analyzed. The vibration waveform signal is processed to obtain dynamic response parameters. The sequence of digital images is processed to obtain the full-field displacement and strain data of the composite specimen surface. The dynamic mechanical properties of the surrounding rock-ore body composite under a specific blasting load are comprehensively evaluated.

[0007] In one possible implementation, in step S100, a laying fixture is used to cast similar materials for the surrounding rock and similar materials for the ore body.

[0008] In one possible implementation, the laying fixture has a panel for blocking surrounding rock-like material or ore-like material, the angle between the panel and the horizontal plane being adjustable, thereby adjusting the laying angle of the surrounding rock-like material or ore-like material, the laying angle being the angle between the outer wall surface of the surrounding rock-like material or ore-like material and the horizontal plane.

[0009] In one possible implementation, the laying fixture is provided with scale lines for measuring the thickness of the surrounding rock or ore body during the pouring process.

[0010] In one possible implementation, in step S100, the three-stage nested telescopic borehole mold includes a main cartridge, an adjusting cartridge, and a buffer cartridge arranged sequentially along the axial direction with gradually decreasing inner diameters. The main cartridge and the adjusting cartridge are telescopically connected, and the adjusting cartridge and the buffer cartridge are telescopically connected. A main chamber is formed inside the main cartridge, an adjusting chamber is formed inside the adjusting cartridge, and a buffer chamber is formed inside the buffer cartridge. A reserved opening is provided on the side of the buffer cartridge, and the reserved opening passes through the buffer chamber. By axial telescopic movement, the volumes of the main chamber and the adjusting chamber are changed to prefabricate charging cavities corresponding to different loading equivalents inside the assembled specimen.

[0011] In one possible implementation, in step S200, the zonal wave velocity measurement method of the acoustic velocimeter is as follows: the sides around the composite specimen are divided into multiple grid areas, and wave velocity measurements are performed along the ore body direction and perpendicular to the ore body direction, respectively. The average wave velocity of each area is taken as the initial value of the basic wave velocity of that area.

[0012] In one possible implementation, in step S200, the vibration acceleration sensors are respectively arranged along the ore body direction and perpendicular to the ore body direction, and the vibration acceleration sensors have probes, which are fixed to the outer wall of the constraint mold by adhesive material.

[0013] In one possible implementation, step S400, the comprehensive evaluation also includes: comparing and iteratively correcting the multi-field data collected in steps S200 and S300 with the numerical simulation results established based on the same composite specimen size, material parameters and loading conditions, in order to verify the test results and construct a mapping relationship database between different explosive loading parameters and the dynamic mechanical response of the composite specimen material.

[0014] In one possible implementation, the constraint mold is a cubic structure with internal dimensions of 100mm × 100mm × 100mm.

[0015] In one possible implementation, step S400, the measurement and recording of the apparent damage characteristics of the composite specimen surface includes: combining the image data of the image monitoring system and the steel ruler measurement data, quantitatively measuring the crack length and blast area size of the composite specimen surface after blasting damage, and defining a size effect coefficient based on the actual simulated size of the composite specimen to quantify the fragmentation scale of the ore body after blasting.

[0016] The beneficial effects of the multi-field testing method for the dynamic mechanical response of blasting in a rock-orebody composite structure provided by this invention are as follows: Compared with the prior art, firstly, it achieves standardization and adjustability of the blasting loading source. By pre-embedding a three-level nested telescopic blast hole mold, an adjustable-volume charging cavity is prefabricated inside the composite specimen, transforming the traditional fixed-yield blasting source into a standard dynamic loading excitation with flexibly adjustable energy levels, enabling systematic comparative testing for different blasting conditions.

[0017] Second, it enables the synchronous acquisition of multi-physics field information. By simultaneously deploying acoustic velocimeters, vibration acceleration sensors, and image monitoring systems, it is possible to acquire data on internal damage, vibration response, and surface deformation fields of the specimen throughout the entire explosive loading process, thus fully revealing the damage evolution law of the model material under explosive load.

[0018] Third, it enables quantitative evaluation of internal damage. By comparing the changes in acoustic wave velocity of the specimens before and after explosive loading, the distribution and extent of invisible damage inside the composite specimen are quantitatively characterized by wave velocity attenuation. This overcomes the limitation of existing technologies that rely solely on visual observation and significantly improves the reliability of test results. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart of a multi-field testing method for the dynamic mechanical response of a rock-ore body blasting system provided in an embodiment of the present invention. Figure 2 A schematic diagram of the layout structure for the multi-field test method of dynamic mechanical response of blasting of surrounding rock-ore body combination provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the laying fixture and its application state for the multi-field testing method of dynamic mechanical response of blasting of surrounding rock-ore body combination provided in an embodiment of the present invention. Figure 4 A schematic diagram of the structure of a three-level nested telescopic blast hole mold for a multi-field test method of dynamic mechanical response of blasting of surrounding rock-ore body combination provided in an embodiment of the present invention; Figure 5 A flowchart of a multi-field test method for dynamic mechanical response of blasting of a surrounding rock-ore body combination, provided in another embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Constraint mold; 2. Laying fixture; 21. Slot; 22. Slot limiting shaft; 23. Panel; 24. Scale line; 3. Three-level nested telescopic blast hole mold; 31. Main cartridge case; 32. Adjusting cartridge case; 33. Buffer cartridge case; 34. Reserved opening; 4. Acoustic velocimeter; 5. Vibration acceleration sensor; 51. Vibration velocimeter; 6. Image monitoring system. Detailed Implementation

[0022] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0024] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0027] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0028] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0029] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0030] In indoor similar model tests of deep hard rock drilling and blasting mining, existing methods have shortcomings in terms of dynamic loading and response information acquisition: the energy level and direction of the loading source are fixed, making it difficult to conduct systematic comparative tests for different blasting conditions; during the test, only single physical quantities such as vibration or surface cracks can be acquired, and it is impossible to simultaneously collect information on internal damage, vibration response and surface deformation field of the specimen, and there is a lack of means to quantify and compare internal damage before and after blasting loading, making it difficult to guarantee the reliability of the test results.

[0031] Based on the above problems, it is necessary to design a multi-field test method for the dynamic mechanical response of the surrounding rock-ore body combination during blasting in order to solve these problems.

[0032] Please refer to the following: Figures 1 to 4 This invention provides a multi-field testing method for the dynamic mechanical response of a rock-ore body composite under blasting. The method involves conducting the entire test within a high-strength transparent constraint mold 1 with internal dimensions of 100mm × 100mm × 100mm. This constraint mold 1 is a cubic structure with an open top and is transparent. It serves both as the outer mold during casting and as a constraint container providing passive confining pressure to the composite specimen during testing. The transparent material also ensures that the image monitoring system 6 can fully visualize and record the deformation process of the internal specimen (the composite specimen, hereinafter referred to as the specimen).

[0033] The method of the present invention specifically includes the following steps: Step S100: Prepare a composite specimen containing a controllable loading source.

[0034] Apply a release lubricant to the inner wall of the constraint mold 1 and lay a layer of plastic film. The release lubricant can be petroleum jelly or release oil, applied evenly to the inner wall of the constraint mold 1. The thickness of the coating should be sufficient to completely cover the inner wall without causing significant liquid accumulation. The purpose of laying the plastic film is to further isolate the similar material from the inner wall of the constraint mold 1, facilitating subsequent demolding operations. The plastic film should be laid flat to avoid significant wrinkles that could affect the surface flatness of the assembled specimen.

[0035] In this step, a laying fixture 2 is used to assist in the pouring of similar materials for the surrounding rock and ore body. The laying fixture 2 includes two slots 21, a slot limiting shaft 22, and a panel 23. The panel 23 is rectangular, with its bottom connected to the slot limiting shaft 22. The two ends of the slot limiting shaft 22 are respectively limited within the two slots 21. The panel 23 is located between the two slots 21. The slot limiting shaft 22 can move within the slots 21, thereby adjusting the installation position of the panel 23 relative to the slots 21, and consequently, adjusting the thickness of the poured similar materials for the surrounding rock or ore body. The slot limiting shaft 22 can rotate circumferentially within the slots 21, thereby adjusting the angle between the panel 23 and the horizontal plane, and consequently, adjusting the angle between the sidewall of the similar materials for the surrounding rock or ore body and the horizontal plane during pouring. The slot 21 limiting groove can limit the position within the slot 21, and its angle after rotation can be limited, using existing technology. Panel 23 is used to block materials similar to surrounding rock or ore body to facilitate casting. Figure 3 The dotted area located on the left side of panel 23 represents materials similar to the surrounding rock or ore body.

[0036] The surface of the panel 23 of the laying clamp 2 should be smoothed to reduce the adhesion between it and similar materials, so as to avoid disturbing the already poured similar materials when the laying clamp 2 is removed later.

[0037] When casting similar materials to the surrounding rock, a layered casting and layer-by-layer vibration method can be adopted. The thickness of each layer should be controlled at 10-15mm. Vibrators or manual tapping of the outer wall of the mold should be used to compact the material and remove air bubbles. The initial setting criterion for the similar materials to the surrounding rock is: when lightly pressing the surface with a finger leaves no obvious indentation, preparations for casting similar materials to the ore body can begin.

[0038] First, adjust the panel 23 of the laying fixture 2 to a suitable position. The angle between the panel 23 and the horizontal plane can be adjusted, thereby adjusting the laying angle of the surrounding rock similar material or ore body similar material. This laying angle is the angle between the outer wall of the surrounding rock similar material or ore body similar material and the horizontal plane. In specific operation, first adjust the panel 23 to the target tilt angle, then attach a detachable tilt sensor to the panel 23. Perform a second fine adjustment based on the real-time reading of the sensor. After adjustment, lock the angle through the slot limiting shaft 22 and remove the sensor. In this way, any tilt angle within the range of 0° to 90° can be accurately simulated.

[0039] A rock-like material (such as gypsum mortar) is poured between the panel 23 and the inner wall of the constraint mold 1 and allowed to initially solidify. The laying fixture 2 is equipped with a scale line 24 for measuring the thickness of the poured rock-like material or ore-like material during the pouring process. Referring to this scale line 24, the position of the panel 23 is precisely adjusted to create a pouring space for the ore body of the target thickness. The ore-like material is then poured within this space. The minimum graduation value of the scale line 24 is 1 mm; by reading the corresponding scale position after the panel 23 is moved, millimeter-level precise control of the ore-like material thickness can be achieved.

[0040] During the casting of materials similar to the ore body, a three-stage nested telescopic blast hole mold 3 is pre-embedded. This three-stage nested telescopic blast hole mold 3 includes a main cartridge 31, an adjusting cartridge 32, and a buffer cartridge 33 arranged sequentially along the axial direction with gradually decreasing inner diameters. The main cartridge 31 and the adjusting cartridge 32 are telescopically connected, as are the adjusting cartridge 32 and the buffer cartridge 33. A main chamber is formed within the main cartridge 31, an adjusting chamber within the adjusting cartridge 32, and a buffer chamber within the buffer cartridge 33. A pre-reserved opening 34 is provided on the side of the buffer cartridge 33, penetrating the buffer chamber. By changing the volume of the main chamber and the adjusting chamber through axial telescopic movement, charging cavities corresponding to different loading equivalents can be prefabricated inside the composite specimen.

[0041] The telescopic adjustment of the three-stage nested telescopic borehole mold 3 should be completed before pre-embedding. Specifically, based on the required blasting equivalent for testing, the relative positions of the main cartridge 31 and the adjusting cartridge 32, and the adjusting cartridge 32 and the buffer cartridge 33, are axially stretched or compressed to achieve the target combined volume of the main chamber and the adjusting chamber. Sealing rings can be installed between each cartridge section to prevent similar material slurry from seeping into the chamber during casting. The thickness of the lubricant, such as petroleum jelly, applied to the outer wall of the mold should be uniform to facilitate subsequent removal without affecting the forming accuracy of the charging chamber.

[0042] Specifically, the exterior of the three-stage nested telescopic borehole mold 3 is coated with a lubricant such as Vaseline, and a cotton rope is tied to the pre-reserved opening 34 for easy removal later. The cotton rope should preferably be pure cotton thread with a diameter of 1mm to 2mm, and its length should extend at least 50mm beyond the top opening of the mold to facilitate clamping with pliers. One end of the cotton rope is tied to the pre-reserved opening 34 on the side of the buffer cartridge 33, and the other end hangs naturally outside the mold.

[0043] After the ore body-similar material is poured, the rotating panel 23 is detached from the ore body and the laying clamp 2 is removed. Finally, the remaining space of the constraint mold 1 is filled with the surrounding rock-similar material. After air drying and hardening, the mold is demolded, and the blast hole mold is steadily removed by clamping the cotton rope with pliers. At this point, a standard charging cavity corresponding to a specific equivalent charge is left inside the ore body of the composite specimen. Finally, black and white matte speckle paint is sprayed on the surface around the composite specimen to facilitate identification by the subsequent image monitoring system 6.

[0044] The process requirements for spraying speckle are as follows: First, spray a layer of white primer to evenly cover the surface of the specimen. After the primer dries, spray black speckle spots. The diameter of the speckle spots is controlled between 0.3 mm and 0.5 mm, and the distribution density is about 50% of the coverage area, forming a randomly distributed high-contrast speckle pattern to meet the speckle quality requirements of digital image correlation algorithms.

[0045] Step S200: Set up a multi-site test environment.

[0046] After demolding, the assembled specimen is placed back into the constraint mold 1, using the rigid walls of the constraint mold 1 to form a passive confining pressure constraint on the assembled specimen. It should be ensured that the gap between the outer wall of the assembled specimen and the inner wall of the mold is uniform, and that the four walls fit tightly together. If local gaps exist, thin shims can be inserted at the gaps for adjustment to ensure uniform transmission of the passive confining pressure.

[0047] The surface of the composite specimen was measured using a sonic velocimeter 4 (existing technology), and the measured wave velocity was recorded as the initial wave velocity field. The specific method for measuring the wave velocity in each zone was as follows: the sides of the composite specimen were divided into multiple grid regions. For example, each of the four sides of the composite specimen was divided into nine square regions (upper, middle, and lower). Wave velocity measurements were taken along the ore body strike and perpendicular to the ore body strike. The average wave velocity of each region was taken as the initial base wave velocity value for that region. The probe of the sonic velocimeter 4 needed to be well coupled to the specimen surface during measurement. A coupling agent (such as Vaseline or a special ultrasonic coupling agent) could be applied between the probe and the specimen surface to improve sound wave transmission efficiency and data stability. During measurement, at least three repeated measurements were performed on each square region, and the average value was taken as the wave velocity value for that region to reduce random errors.

[0048] A vibration acceleration sensor 5 (existing technology) is fixed to the outer wall of the constraint mold 1. The vibration acceleration sensor 5 is deployed along and perpendicular to the ore body strike. Its probe is fixed to the outer wall of the constraint mold 1 using an adhesive material, ensuring a firm fit between the probe and the surface of the constraint mold 1. The vibration acceleration sensor 5 should preferably be a piezoelectric accelerometer with a frequency response range of 0.5Hz to 10kHz and a sensitivity of not less than 100mV / g to meet the wideband acquisition requirements of blasting vibration signals. The adhesive material can be epoxy resin or cyanoacrylate quick-drying adhesive. Before bonding, the bonding area on the outer wall of the constraint mold 1 should be cleaned with alcohol to ensure the surface is free of oil and dust. After bonding, the curing time should be no less than 5 minutes to ensure a rigid connection between the probe and the mold surface, avoiding signal transmission loss. The vibration acceleration sensor 5 is electrically connected to a vibration velocimeter 51 (existing technology, capable of velocity measurement) via a wiring harness.

[0049] The purpose of measuring wave velocity along and perpendicular to the ore body strike is to detect the anisotropic characteristics of the composite specimen in different directions, providing more comprehensive benchmark data for subsequent damage analysis.

[0050] An image monitoring system 6 (which is existing technology) is set up and aligned with the observation surface of the assembled specimen. The image monitoring system 6 is a digital image correlation monitoring system, which includes two high-speed cameras, set up directly in front of the speckle observation surface of the specimen, and the focus and field of view are adjusted to clearly capture the speckle image of the specimen surface.

[0051] The setup parameters for Image Monitoring System 6 (Digital Image Correlation Monitoring System) are as follows: the optical axis angle between the two high-speed cameras should be set to 25° to 30°, the camera resolution should be no less than 5 megapixels, and the sampling frame rate should be no less than 100fps to ensure clear capture of the rapid deformation process during explosive loading. After setup, system calibration should be performed. A calibration board should be used to take multi-angle photos at the observation surface of the specimen to obtain the camera's internal and external parameters. The calibration accuracy should be better than 0.01 pixels.

[0052] Step S300: Perform dynamic loading and synchronous acquisition.

[0053] A blasting loading source of a predetermined amount is placed into the charge chamber and filled in, for example, a specific amount of black powder or other initiating material is placed into the charge chamber, and the upper part is filled with stemming material to simulate real blasting conditions.

[0054] The vibration acceleration sensor 5 and the image monitoring system 6 are simultaneously activated to enter the acquisition state. Then, the loading source is detonated, and vibration waveform signals and sequential digital images of the surface of the composite specimen are acquired in real time throughout the entire blasting loading process. During the blasting loading process, the vibration acceleration sensor 5 records vibration waveform data in real time, while the image monitoring system 6 continuously captures speckle deformation images of the surface of the composite specimen at a high frame rate.

[0055] The explosive loading source can be selected with different specifications of black powder or other initiating materials according to the test requirements. The charge amount can range from 0.1g to 5g to achieve loading excitation of different energy levels. When loading, a special tool should be used to gently push the initiating material into the bottom of the loading chamber to avoid spillage or improper accumulation. The stemming material can be modeling clay or clay, and the filling depth should be no less than one-third of the depth of the loading chamber to effectively simulate the borehole plugging effect in actual blasting.

[0056] When simultaneously activating the vibration acceleration sensor 5 and the image monitoring system 6, microsecond-level synchronization accuracy can be achieved using an external trigger signal or synchronization cable. The data acquisition system should be equipped with a pre-trigger function, meaning data acquisition should begin before detonation, with a pre-trigger time of no less than 0.5 seconds, to ensure complete recording of data from before to after the blasting loading process. Detonation can be performed remotely using an electric igniter to ensure operator safety. Ignition voltage and current should meet the reliable ignition parameter requirements of the detonating material.

[0057] Step S400: Multi-field information analysis and material performance evaluation.

[0058] After loading, the surface damage characteristics of the composite specimen were measured and recorded. Specifically, this included: combining image data from the image monitoring system 6 and steel ruler measurement data, quantitatively measuring the crack length and blast area size of the composite specimen after blasting damage, and defining a size effect coefficient based on the actual simulated size of the composite specimen to quantify the fragmentation scale of the ore body after blasting.

[0059] The size effect coefficient is defined as the ratio of the actual simulated size of the composite specimen to the size of the indoor standard specimen, used to extrapolate indoor test results to actual engineering scales.

[0060] The wave velocity field after loading is obtained again using the acoustic velocimeter 4. By comparing the changes in wave velocity before and after loading, the difference between the wave velocity field after loading and the initial wave velocity field obtained in step S200 is calculated. Based on the magnitude and distribution of wave velocity attenuation, the internal damage distribution of the composite specimen is quantitatively analyzed.

[0061] The formula for calculating the wave velocity attenuation rate can be expressed as: Wave velocity attenuation rate = (Initial wave velocity - Wave velocity after loading) / Initial wave velocity × 100%. When the wave velocity attenuation rate exceeds a preset threshold, significant damage is considered to have occurred in that area. The preset threshold can be determined by referring to empirical data from acoustic wave testing of similar materials, and is typically taken as 5% to 10%.

[0062] Process vibration waveform signals to obtain dynamic response parameters, such as importing vibration waveform data into analysis software to obtain dynamic response parameters such as peak particle vibration velocity.

[0063] Processing sequential digital images yields full-field displacement and strain data on the surface of the composite specimen. For example, sequential images from the image monitoring system 6 are imported into the processing software, and relevant algorithms are used to calculate the full-field displacement, strain field, and complete spatiotemporal evolution process of crack initiation and propagation on the specimen surface.

[0064] Based on the data from the above multiple tests, the dynamic mechanical properties of the surrounding rock-orebody combination under specific blasting loads were evaluated.

[0065] To further verify the reliability of the test results, please refer to [link / reference]. Figure 5Step S500, performed after step S400, further includes the comprehensive evaluation of: comparing and iteratively correcting the multi-field data collected in steps S200 and S300 with the numerical simulation results established based on the same composite specimen size, material parameters, and loading conditions, verifying the test results, and using the calibrated numerical model to extend the simulation analysis to more working conditions, and constructing a database of mapping relationships between different blasting loading parameters and the dynamic mechanical response of the composite specimen material, quantitatively determining the blasting charge amount, and thus providing a precise quantitative basis for the blasting charge amount for geotechnical engineering blasting model tests.

[0066] The numerical simulation modeling process includes: establishing a three-dimensional geometric model based on the actual dimensions of the composite specimen; modeling the ore body according to the inclination angle and thickness parameters adjusted by the fixture 2 in step S100; and modeling the blast holes according to the actual expanded and contracted dimensions of the three-level nested telescopic blast hole mold 3. A multi-scale mesh generation strategy is adopted, with a finer mesh used around the blast holes and at the ore body-surrounding rock interface. Material parameters are assigned according to the measured mechanical parameters of similar materials to the surrounding rock and ore body. The stress, strain, and damage field inside the specimen under blasting load are solved through iterative calculation, outputting crack propagation paths and damage contour maps, which are then compared and verified with the measured data obtained in step S400.

[0067] Error evaluation indicators for closed-loop comparisons may include: relative error of crack length not exceeding 15%, relative error of damaged area not exceeding 20%, and relative error of peak vibration particle velocity not exceeding 10%. When the error exceeds the above range, the constitutive parameters or boundary conditions of the numerical model should be adjusted until the accuracy requirements are met.

[0068] The mapping database is constructed as follows: using blasting loading equivalent, ore body dip angle, and ore body thickness as input variables, and damage range, crack length, and vibration peak value as output variables, multiple sets of data records are established to form a basis for selecting blasting parameters that can be queried and referenced in engineering projects.

[0069] By adjusting the three-level nested telescopic blast hole mold 3 to different lengths and placing it inside a similar material of the ore body, charging cavities of different volumes can be formed, thereby changing the loading equivalent. Alternatively, the angle and thickness of the laying fixture 2 can be adjusted (to change the geological structure). By repeating the test process of steps S100 to S400, a database of the dynamic mechanical properties of this type of model material under different blasting conditions can be systematically established.

[0070] Finally, by combining the three types of data—vibration response, surface deformation, and internal damage—a complete test report on the dynamic mechanical response and damage characteristics of the surrounding rock-ore body combination under this level of blasting load is generated.

[0071] The beneficial effects of the multi-field testing method for the dynamic mechanical response of blasting in a rock-orebody composite structure provided by this invention are as follows: Compared with the prior art, firstly, it achieves standardization and adjustability of the blasting loading source. By pre-embedding a three-level nested telescopic blast hole mold 3, an adjustable-volume charging cavity is prefabricated inside the composite specimen, transforming the traditional fixed-yield blasting source into a standard dynamic loading excitation with flexibly adjustable energy levels, enabling systematic comparative testing for different blasting conditions.

[0072] Second, it enables the synchronous acquisition of multi-physics field information. By simultaneously deploying the acoustic velocimeter 4, vibration acceleration sensor 5, and image monitoring system 6, it is possible to simultaneously acquire data on internal damage, vibration response, and surface deformation fields of the specimen throughout the entire explosive loading process, thus fully revealing the damage evolution law of the model material under explosive load.

[0073] Third, it enables quantitative evaluation of internal damage. By comparing the changes in acoustic wave velocity of the specimens before and after explosive loading, the distribution and extent of invisible damage inside the composite specimen are quantitatively characterized by wave velocity attenuation. This overcomes the limitation of existing technologies that rely solely on visual observation and significantly improves the reliability of test results.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-field testing method for the dynamic mechanical response of blasting in a rock-orebody composite, characterized in that, Includes the following steps: S100. Inside the transparent constrained mold, similar materials for surrounding rock and similar materials for ore body are poured in sequence. During the process of pouring ore-like material, a three-level nested telescopic blast hole mold is pre-embedded. After the ore-like material hardens, the mold is removed to form an adjustable charge cavity in the ore-like material area. S200. Spray speckle coating onto the surface of the demolded composite specimen and place it back into the constraint mold. Use the rigid wall of the constraint mold to form a passive confining constraint on the composite specimen. Use an acoustic velocimeter to measure the wave velocity in sections on the surface of the composite specimen and record it as the initial wave velocity field. Fix a vibration acceleration sensor on the outer wall of the constraint mold and set up an image monitoring system to align with the observation surface of the composite specimen. S300. Place the explosive loading source of the set equivalent into the charging cavity and fill it. At the same time, start the vibration acceleration sensor and the image monitoring system, and then detonate the loading source. Collect the vibration waveform signal and the sequence of digital images of the surface of the composite specimen in real time during the entire explosive loading process. S400. After loading, the surface damage characteristics of the composite specimen are measured and recorded. The wave velocity field after loading is obtained again using the sonic velocimeter. By comparing the changes in wave velocity before and after loading, the internal damage distribution of the composite specimen is quantitatively analyzed. The vibration waveform signal is processed to obtain dynamic response parameters. The sequence of digital images is processed to obtain the full-field displacement and strain data of the composite specimen surface. The dynamic mechanical properties of the surrounding rock-ore body composite under a specific blasting load are comprehensively evaluated.

2. The multi-field testing method for the dynamic mechanical response of blasting in a surrounding rock-ore body composite as described in claim 1, characterized in that, In step S100, a laying fixture is used to cast similar materials for the surrounding rock and similar materials for the ore body.

3. The multi-field testing method for the dynamic mechanical response of a surrounding rock-ore body composite during blasting, as described in claim 2, is characterized in that... The laying clamp has a panel for blocking surrounding rock similar materials or ore body similar materials. The angle between the panel and the horizontal plane is adjustable, thereby adjusting the laying angle of the surrounding rock similar materials or ore body similar materials. The laying angle is the angle between the outer wall surface of the surrounding rock similar materials or ore body similar materials and the horizontal plane.

4. The multi-field testing method for the dynamic mechanical response of blasting in a surrounding rock-ore body composite as described in claim 2, characterized in that, The laying fixture is equipped with scale lines, which are used to measure the thickness of the surrounding rock or ore body during the pouring process.

5. The multi-field testing method for the dynamic mechanical response of a surrounding rock-ore body composite during blasting as described in claim 1, characterized in that, In step S100, the three-stage nested telescopic borehole mold includes a main cartridge, an adjusting cartridge, and a buffer cartridge arranged sequentially along the axial direction with gradually decreasing inner diameters. The main cartridge and the adjusting cartridge are telescopically connected, and the adjusting cartridge and the buffer cartridge are telescopically connected. A main chamber is formed inside the main cartridge, an adjusting chamber is formed inside the adjusting cartridge, and a buffer chamber is formed inside the buffer cartridge. A reserved opening is provided on the side of the buffer cartridge, and the reserved opening passes through the buffer chamber. By axial telescopic movement, the volume of the main chamber and the adjusting chamber is changed to prefabricate charging cavities corresponding to different loading equivalents inside the assembled specimen.

6. The multi-field testing method for the dynamic mechanical response of a surrounding rock-ore body composite during blasting as described in claim 1, characterized in that, In step S200, the zonal wave velocity measurement method of the acoustic velocimeter is as follows: the side surface around the composite specimen is divided into multiple grid areas, and wave velocity measurements are performed along the ore body direction and perpendicular to the ore body direction, respectively. The average wave velocity of each area is taken as the initial value of the basic wave velocity of that area.

7. The multi-field testing method for the dynamic mechanical response of a surrounding rock-ore body composite during blasting as described in claim 1, characterized in that, In step S200, the vibration acceleration sensors are respectively arranged along the direction of the ore body and perpendicular to the direction of the ore body. The vibration acceleration sensors have probes, and the probes are fixed to the outer wall of the constraint mold by adhesive material.

8. The multi-field testing method for the dynamic mechanical response of a surrounding rock-ore body composite during blasting as described in claim 1, characterized in that, In step S400, the comprehensive evaluation also includes: comparing and iteratively correcting the multi-field data collected in steps S200 and S300 with the numerical simulation results established based on the same composite specimen size, material parameters and loading conditions in a closed loop, so as to verify the test results and construct a mapping relationship database between different explosive loading parameters and the dynamic mechanical response of the composite specimen material.

9. The multi-field test method for dynamic mechanical response of blasting of surrounding rock-ore body combination as described in claim 1, wherein the constraint mold is a cubic structure with internal dimensions of 100mm×100mm×100mm.

10. The multi-field testing method for the dynamic mechanical response of a surrounding rock-ore body composite during blasting as described in claim 1, characterized in that, In step S400, the measurement and recording of the apparent damage characteristics of the composite specimen surface includes: combining the image data of the image monitoring system and the steel ruler measurement data, quantitatively measuring the crack length and blast area size of the composite specimen surface after blasting damage, and defining a size effect coefficient based on the actual simulated size of the composite specimen to quantify the fragmentation scale of the ore body after blasting.

Images