Method for testing the crushing effect of concrete based on fiber grating measurement

Abstract

The present application relates to the technical field of blasting damage test, in particular to a concrete crushing effect test method based on a fiber grating measurement method, comprising the following steps: step S1, a sensor layout step: embedding or surface mounting one or more fiber grating sensors in a concrete test piece; step S2, a load application step: pouring a static breaking agent into a blast hole arranged in the concrete test piece to apply a static breaking load; step S3, a data synchronous acquisition step: through a fiber sensing analyzer; the present application adopts a fiber grating sensor networking and performs high-frequency synchronous data acquisition, realizes transparent observation on the blasting damage process through intelligent analysis on feature points on a strain / displacement time history curve, and the complete dynamic sequence of energy quantization cracks from cracking, expansion to penetration, which completely breaks the process black box and provides whole-process data support for the research on the concrete crushing mechanism.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blasting damage test, in particular to a concrete crushing effect test method based on fiber grating measurement method. BACKGROUND

[0002] As a safe and environmentally friendly crushing method, static blasting technology is increasingly widely used in the demolition of rock and concrete structures in sensitive environments. The core of the crushing effect is the expansion pressure generated by the hydration reaction of static breaking agent, and the crack initiation and propagation behavior induced by the pressure in the medium. Therefore, accurate testing and analysis of the blasting effect is the key to optimizing blasting parameters and improving blasting efficiency.

[0003] Currently, the testing and research of this process mainly rely on two ways: one is the electrical measurement method based on resistance strain gauge, and the other is the macroscopic morphology observation method after blasting. Although the electrical measurement method can provide certain strain data, its signal is easily affected by electromagnetic interference, has poor long-term stability, and is difficult to work reliably in corrosive (such as underwater) environments. More importantly, the data obtained by traditional electrical measurement method is often discrete and local, and cannot capture the whole process information of crack dynamic expansion with high density and high precision. The macroscopic observation method is more lagging and rough, and can only provide the final result of whether the crack occurs or not, and cannot reveal the internal mechanism.

[0004] Due to the lack of accurate and quantitative description of the damage process, researchers have difficulty in establishing effective mathematical models to accurately predict the blasting effect. The constitutive model and parameters of the current static blasting numerical simulation used to guide construction are mostly dependent on empirical estimation or macroscopic back calculation, which leads to limited prediction accuracy and weak universality. SUMMARY

[0005] The present application aims to overcome the defects of the prior art and provides a concrete crushing effect test method based on fiber grating measurement method, comprising the following steps:

[0006] Step S1, sensor layout step: one or more fiber grating sensors are embedded inside or mounted on the surface of the concrete test piece;

[0007] Step S2, load application step: static breaking agent is poured into the blast hole provided in the concrete test piece to apply static breaking load;

[0008] Step S3, data synchronous acquisition step: the center wavelength change data of all the fiber grating sensors under the action of the load are synchronously acquired in real time by a fiber sensing analyzer;

[0009] Step S4, data intelligent analysis step: the center wavelength change is demodulated into strain or displacement data, and a strain or displacement time history curve is generated;

[0010] Step S5, a damage process tracing step: analyzing the characteristic points on the time-history curve, including the strain jump point, jump amplitude, time interval of jump and the falling phenomenon, thereby judging the crack initiation time, expansion sequence, expansion speed and internal pressure relief process;

[0011] In step S1, the layout positions of the fiber grating sensors include the middle perpendicular line of the blast hole connecting line, the midpoint of the connecting line between two blast holes, and the vicinity of the free surface of the concrete specimen, for monitoring the crack initiation, penetration and surface opening processes.

[0012] Preferably, in step S1, the fiber grating sensors include one or more of embedded fiber strain gauges, reusable fiber strain gauges and fiber grating displacement gauges.

[0013] Preferably, in step S1, the concrete specimen includes a steel reinforcement binding cage and a cubic concrete structure poured in the steel reinforcement binding cage, and four blast holes in a rectangular distribution extending downward from the top surface are arranged on the cubic concrete structure.

[0014] In step S1, the first fiber grating sensor is arranged at a position between two adjacent blast holes and between a blast hole and the free surface; and the second fiber grating sensor is an embedded fiber strain gauge arranged inside the concrete specimen.

[0015] Preferably, in step S1, the embedded fiber strain gauge is fixed on the steel reinforcement cage before pouring the concrete specimen; and the reusable fiber strain gauge and the fiber grating displacement gauge are fixed on the surface of the concrete specimen by epoxy resin glue or mechanical clamps.

[0016] Preferably, in step S3, the fiber sensing analyzer is a multi-channel analyzer supporting high-frequency synchronous data acquisition of 25Hz or above 100Hz for multiple sensors.

[0017] Preferably, in step S5, the first monitored strain jump time is determined as the crack initiation time, the time interval between multiple jumps is determined as the time difference of crack expansion in sequence, and the falling phenomenon after the jump is determined as the pressure relief process of high-pressure gas in the blast hole.

[0018] Preferably, before step S1, a digital twin model construction step is further included, and a static blasting numerical simulation model completely corresponding to the concrete specimen is established according to the geometric size, material properties, blast hole position and parameters, and the layout position of the fiber grating sensor.

[0019] Preferably, the data obtained by the method is used to construct or optimize the digital twin model of static blasting.

[0020] Preferably, the crack initiation time, propagation speed and pressure relief process data analyzed in step S5 are used to calibrate the rock constitutive model parameters and static breaking agent inflation pressure time curve parameters in the static blasting numerical simulation.

[0021] Preferably, the calibration process is an iterative closed loop, and the calibrated digital twin model is used to predict the blasting effect under new working conditions, and the prediction results are verified and fed back again through the method of steps S1 to S5, so as to realize continuous self-optimization of the model.

[0022] Compared with the prior art, the advantages of the present application are:

[0023] The present application adopts fiber grating sensor networking and high-frequency synchronous data acquisition, realizes transparent observation of the blasting damage process through intelligent analysis of the characteristic points on the strain / displacement time curve, and energy quantization of the complete dynamic sequence from crack initiation, propagation to penetration, which completely breaks the process black box and provides full-process data support for studying the concrete breaking mechanism.

[0024] The test system is built around the new generation of sensing technology, fiber grating, which has advantages such as anti-electromagnetic interference, corrosion resistance, and good long-term stability, and is especially suitable for complex or underwater environments, supports multi-channel high-frequency synchronous acquisition, ensures the capture of millisecond-level crack propagation process, and provides a solid data foundation for in-depth analysis.

[0025] The test data collected by the fiber grating sensor can be used to build or optimize the digital twin model of static blasting, provide accurate verification and calibration data for the model, and through an iterative feedback mechanism, realize accurate inversion of key parameters such as rock constitutive parameters and inflation pressure curve, significantly improve the prediction ability of numerical simulation, and promote the transformation of simulation model from experience-driven to data-driven.

[0026] By combining the use of embedded and reusable strain gauges and displacement meters, multi-dimensional synchronous monitoring of internal strain, surface strain and crack opening displacement of concrete is realized, and complete damage field information is constructed, providing a systematic solution for comprehensive evaluation of breaking effect. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures can be represented by a like numeral. For purposes of clarity, not every component can be called out in every drawing. There is now being described by way of example various embodiments of aspects of the application with reference to the attached drawings, in which:

[0028] Figure 1 is a schematic diagram of the sensor arrangement position inside the concrete specimen shown in the embodiments of the present application;

[0029] Figure 2 This is a physical image of the concrete specimen shown in the embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram showing the sensor arrangement on the top surface of the concrete specimen in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram showing the sensor arrangement on the side of the concrete specimen according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the top surface of the concrete specimen after it has been blown apart, as shown in an embodiment of the present invention.

[0033] Figure 6 This is the strain time history curve at measuring point b shown in the embodiment of the present invention;

[0034] Figure 7 This is the strain time history curve at measuring point d shown in the embodiment of the present invention;

[0035] Figure 8a This is the strain time history curve measured by the reusable fiber optic strain gauge No. ② shown in the embodiment of the present invention;

[0036] Figure 8b yes Figure 8a A magnified view of a portion of the image;

[0037] Figure 9 The displacement time history curve is obtained by setting a fiber optic grating displacement meter at position ③ in the embodiment of the present invention.

[0038] Figure 10 This is a schematic diagram of the side of a concrete specimen after it has been blown apart, as shown in an embodiment of the present invention.

[0039] Figure 11 The displacement time history curve is obtained by setting a fiber optic grating displacement meter at position ⑤ in the embodiment of the present invention. Detailed Implementation

[0040] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0041] Aspects of the present disclosure are described herein with reference to the drawings, in which are shown many illustrative embodiments. Embodiments of the present disclosure are not necessarily intended to include all aspects of the present disclosure. It should be understood that various concepts and embodiments introduced above and discussed in greater detail below can be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any particular manner of implementation. Additionally, some aspects of the present disclosure can be utilized to alone or in any appropriate combination with other aspects of the present disclosure.

[0042] In conjunction with Figures 1 to 4 The present disclosure proposes a method for testing the concrete breaking effect based on fiber grating measurement, comprising the following steps:

[0043] Step S1, sensor layout step: embedding or mounting one or more fiber grating sensors inside or on the surface of the concrete test piece;

[0044] Step S2, load application step: pouring static breaking agent into the blast hole provided in the concrete test piece to apply a static breaking load;

[0045] Step S3, data synchronous acquisition step: through the fiber sensing analyzer, the center wavelength change data of all fiber grating sensors under the action of the load is synchronously acquired in real time;

[0046] Step S4, data intelligent analysis step: demodulating the center wavelength change into strain or displacement data, and generating a strain or displacement time history curve;

[0047] Step S5, damage process tracing step: analyzing the characteristic points on the time history curve, including the strain jump point, jump amplitude, time interval and fall-back phenomenon, to determine the crack initiation time, propagation sequence, propagation speed and internal pressure relief process;

[0048] In step S1, the layout positions of the fiber grating sensors include the midline of the blast hole connecting line, the midpoint of the connecting line between the two blast holes, and the vicinity of the free surface of the concrete test piece, for monitoring the crack initiation, penetration and surface opening process.

[0049] The above method realizes accurate capture and in-depth analysis of dynamic information of the whole damage process, improves the test from result observation to process tracing level, and provides unprecedented data support for studying the damage mechanism. Especially, the processing of the monitoring data in steps S4 and S5 can determine the crack initiation time, propagation sequence, propagation speed and internal pressure relief process, so that the whole concrete breaking process is visually presented.

[0050] In an optional embodiment, in step S1, the fiber grating sensor comprises one or more of the following: a buried fiber strain gauge, a reusable fiber strain gauge, and a fiber grating displacement gauge.

[0051] It should be understood that different testing requirements require different sensing methods, internal strain, surface strain, and macro displacement are different observation quantities. Through multiple sensors, multi-dimensional and full-view measurement capabilities can be provided. The buried measurement can measure the internal true strain, the reusable fiber strain gauge is convenient for surface pasting, has low cost and can be reused, and the displacement gauge directly measures the crack width, and the combination of the three can construct complete damage field information.

[0052] Further, in step S1, the concrete test piece comprises a steel binding cage and a cubic concrete structure poured in the steel binding cage, and four blast holes in a rectangular distribution extending downward from the top surface are arranged on the cubic concrete structure.

[0053] The first fiber grating sensor is arranged between the adjacent two blast holes and between the blast hole and the free surface; the second fiber grating sensor is a buried fiber strain gauge arranged in the interior of the concrete test piece.

[0054] Specifically, in combination with the embodiments shown in Figure 1 and Figure 3 , the fiber grating sensor comprises a buried fiber strain gauge, a reusable fiber strain gauge, and a fiber grating displacement gauge, wherein, in Figure 1 , three buried fiber strain gauges are arranged in the interior of the concrete test piece, and are arranged at points b, c, and d shown in Figure 1 . In Figure 3 , the reusable fiber strain gauges are arranged at ① and ② on the upper surface of the concrete test piece, and the fiber grating displacement gauge is arranged at ③. As shown in Figure 11 , the reusable fiber strain gauges are arranged at ④ on the side surface of the concrete test piece, and the fiber grating displacement gauge is arranged at ⑤.

[0055] Further, in the above step S1, the buried fiber strain gauge is fixed on the steel framework before the concrete test piece is poured; the reusable fiber strain gauge and the fiber grating displacement gauge are fixed on the surface of the concrete test piece by epoxy resin glue or mechanical clamps.

[0056] The design of the above sensor arrangement position and method aims to construct a three-dimensional, multi-dimensional monitoring network to capture the whole process of crack initiation, expansion and surface opening. The sensors arranged in the key paths such as the perpendicular line of the blast hole connection and the midpoint of the two holes can effectively capture the initiation and expansion process of the main crack; the displacement meters arranged near the free surface are used to monitor the final opening behavior and surface failure mode of the crack; the internal embedded strain gauges reflect the real strain state of the concrete interior and reveal the initial damage location; the surface reusable strain gauges and displacement meters make up for the areas that cannot be covered by internal sensors, forming a three-dimensional monitoring system combining internal and external, and complementing strain and displacement.

[0057] The above layout strategy ensures the comprehensiveness of data in space and the diversity of physical quantities, providing a multi-source and reliable data basis for subsequent construction of high-precision digital twin models, inversion of material parameters and damage process.

[0058] Further, in step S3, the optical fiber sensing analyzer is a multi-channel analyzer that supports high-frequency synchronous data acquisition of 25Hz or more than 100Hz for multiple sensors.

[0059] It should be understood that crack propagation is a rapid dynamic process at the millisecond or even microsecond level, and low-frequency acquisition may lose key details.

[0060] Therefore, high-frequency synchronous data acquisition of 25Hz or more than 100Hz can ensure the capture of every moment of crack initiation and expansion, guarantee the timeliness and accuracy of the data, and lay the foundation for subsequent accurate analysis.

[0061] Further, in step S5, the first monitored strain jump moment is determined as the crack initiation moment, the time interval between multiple jumps is determined as the time difference of crack expansion, and the post-jump drop phenomenon is determined as the high-pressure gas pressure relief process in the blast hole.

[0062] In this way, abstract curve features can be corresponded to specific physical phenomena (such as initiation, expansion, and pressure relief), enabling the computer to automatically identify and understand the damage process, achieving automation and intelligentization of analysis, and improving research efficiency.

[0063] In the preferred embodiment, before step P1, a digital twin model construction step is further included, which establishes a static blasting numerical simulation model completely corresponding to the concrete specimen according to the geometric size, material properties, blast hole position and parameters, and the layout position of the fiber Bragg grating sensor.

[0064] The data obtained by the above method is used to construct or optimize the digital twin model of static blasting.

[0065] It should be understood that the ultimate purpose of the test is not only to understand one experiment, but also to improve the understanding of the general law and the prediction ability. The method provided in the application can provide verification and optimization data for the digital twin model, which forms a closed loop from virtual simulation to physical verification and feedback optimization of virtual simulation, so that the entire technical system has the ability to continuously evolve.

[0066] Further, the crack initiation time, expansion speed and pressure relief process data analyzed in step S5 are used to calibrate the rock constitutive model parameters and static breaking agent expansion pressure time curve parameters in the static blasting numerical simulation.

[0067] Specifically, the static blasting effect is as shown in Figure 5 During the experiment, the reusable optical fiber strain gauge No. 1 fell off the surface of the concrete test piece due to excessive strain of the concrete test piece, and the measured data exceeded the range, so it was discarded. One embedded strain gauge (position of measuring point c) did not measure data due to unknown reasons.

[0068] As shown in Figure 6 The strain time curve at measuring point b, the strain test direction of measuring point b only forms a crack, so there is only one strain jump on the measured strain time curve. The expansion stress generated by the static breaking agent due to the cracking of the reinforced concrete test piece is instantaneously unloaded, the stress is applied to the fiber Bragg grating strain gauge, causing the strain to intensify, which is reflected on the strain time curve as a strain jump. The crack formation time is 56min after starting data collection, Figure 7 No strain drop is observed.

[0069] As shown in Figure 7 This is the strain time curve measured by the fiber Bragg grating strain gauge at the position of measuring point d. The position of this strain gauge is at the center of the four blast holes, so the strain time curve starts to steadily rise 13min after starting collection, which is earlier than the measurement result of the b-point grating strain gauge. This is because the expansion pressure in the four blast holes acts together.

[0070] When 55min after starting collection, the strain time curve appears a jump, which is due to the instantaneous release of the expansion stress generated by the static breaking agent due to the cracking of the reinforced concrete test piece, the stress is applied to the fiber Bragg grating strain gauge, causing the strain to intensify, which is reflected on the strain time curve as a strain jump. 3min later, the strain time curve has another jump, which is because another crack is formed in the reinforced concrete test piece.

[0071] As shown in Figure 5It can be seen that the main cracks formed by reinforced concrete are two transverse cracks and two longitudinal cracks. The strain generated by the two longitudinal cracks cannot be measured because it is not consistent with the measurement direction of the embedded FBG strain gauge. The two transverse cracks are consistent with the measured strain-time curve, and the crack far from the measurement point d occurs first, and the crack close to the measurement point d occurs later. This is because the crack close to the measurement point has a larger crack width and is closer to the test point, resulting in a larger change in the strain measured by the strain gauge. The sudden change in the strain-time curve is more obvious, which is the second sudden change in the figure.

[0072] In addition, the strain in the figure has a falling phenomenon twice, which is due to the fact that when the crack is formed, the water vapor pressure formed by the excess water in the blast hole under the action of hydration reaction releases pressure in the crack, thereby causing the pressure of the measurement point to increase and the strain to increase. When the pressure is released, the pressure of the measurement point decreases, thereby causing the strain to fall.

[0073] In combination with Figure 8a and Figure 8b , which is the strain-time curve measured by the reusable FBG strain gauge No. 2. As can be seen from the figure, the strain-time curve starts to steadily rise 15 minutes after the start of collection, which is the result of the combined action of the expansion pressure generated by the static broken slurry in the four blast holes through hydration reaction. About 56 minutes after the start of collection, cracks are formed around the strain gauge, and then a new crack is formed in the reinforced concrete specimen every 3 minutes, accompanied by the formation of cracks, which causes the strain of the concrete specimen to jump, which is reflected in the strain-time curve as a sharp increase in the strain. In each sudden change process, the strain falls.

[0074] As Figure 9As shown, this is the displacement time history curve measured by a fiber optic grating displacement gauge at location ③. Within the measurement area of ​​the displacement gauge, the reinforced concrete specimen developed two distinct cracks under the expansion pressure, consistent with the displacement time history curve. The smaller crack on the left appeared first. Because this crack is smaller, the increase in displacement is also smaller, resulting in a smaller displacement jump in the displacement time history curve. About 200 seconds after the small crack appeared, the larger crack on the right formed. The larger crack has a larger crack width and causes a larger displacement change, making the displacement jump in the displacement time history curve more obvious. The displacement time history curve shows that the initial crack width of the small crack was about 15 mm, but the displacement decreased after the pressure was released, and the final crack width was 10 mm. The initial crack width of the large crack was 35 mm, but it eventually stabilized at 25 mm. The reason for the change in crack width, i.e., the phenomenon of a jump followed by a drop in the displacement time history curve, is that when the crack forms, the excess water in the borehole is released under the exothermic effect of the hydration reaction, resulting in increased pressure and thus increased displacement. After the pressure is released, the pressure decreases, and under the action of the steel bars in the concrete specimen, the cracks recover a certain displacement deformation, thereby causing a reduction in crack width.

[0075] like Figures 10 to 11 As shown, Figure 11 The displacement time history curve measured by the fiber optic grating displacement gauge shows that within the gauge's measurement area, the reinforced concrete specimen developed two distinct cracks, one large and one small, under expansion pressure. The crack on the left side is narrower, while the crack on the right side is wider. This is consistent with... Figure 5 The displacement time history curves correspond to this. The smaller crack on the left appears first; because it is smaller, the increase in displacement is also smaller, resulting in a smaller displacement jump in the displacement time history curve. About 5 minutes after the smaller crack appears, a larger crack forms on the right. The larger crack is wider and causes a larger displacement change, making the displacement jump in the displacement time history curve more pronounced. The displacement time history curves show that the width of the smaller crack is approximately 6 mm, and the width of the larger crack is approximately 9 mm. No displacement drop after the jump is observed in the displacement time history curves. The reason for this is that the cracks on the side of the concrete specimen are smaller than the cracks on the top. Excess water in the borehole, under the exothermic effect of the hydration reaction, releases water vapor pressure in the top crack, thus preventing a displacement drop in the displacement time history curve measured by the side-mounted fiber optic displacement gauge.

[0076] As analyzed above based on field observations and experimental data, the failure of reinforced concrete specimens is not instantaneous but rather involves a time-dependent process. The fracture process of reinforced concrete specimens mainly involves crack initiation, crack development, and the final stage of media splitting.

[0077] Further, the calibration process is an iterative closed loop, and the calibrated digital twin model is used to predict the blasting effect under new working conditions, and the prediction result is verified and fed back through the method of steps S1 to S5 again, so as to realize the continuous self-optimization of the model.

[0078] As described above, the digital twin model corresponding to the entity specimen is constructed before the experiment, the mapping relationship between virtual and reality can be established, and the real data collected subsequently can be directly used for model verification and calibration. The calibration process is designed as an iterative closed loop, the continuous self-optimization and generalization ability of the digital twin model can be realized, the constitutive model and the swelling pressure curve are gradually corrected through multiple experiment feedbacks, the prediction accuracy of the model under new working conditions is enhanced, the model has the ability to adapt to different concrete strength, blast hole arrangement, breaking agent type and other variables, and a benign cycle of data-driven simulation can be formed, and the static blasting technology is promoted from experience construction to intelligent design evolution.

[0079] Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Those skilled in the art without departing from the spirit and scope of the present application can make various modifications and decorations. Therefore, the protection scope of the present application shall be subject to the definition of the claims.

Claims

1. A method for testing the concrete fracture effect based on fiber optic grating measurement, characterized in that, Includes the following steps: Step S1, Sensor Deployment Steps: Embed one or more fiber optic grating sensors inside the concrete specimen or install them on its surface. Step S2, Load Application Step: Inject static fracturing agent into the boreholes set in the concrete specimen to apply static fracturing load; Step S3, Data Synchronization Acquisition Step: Using an optical fiber sensor analyzer, the center wavelength change data of all the fiber optic grating sensors under load is acquired in real time and synchronously. Step S4, Intelligent Data Analysis Step: Demodulate the change in center wavelength into strain or displacement data, and generate strain or displacement time history curves; Step S5, Failure Process Tracing Step: Analyze the characteristic points on the time history curve, including strain jump points, jump amplitude, jump time interval and fall phenomenon, and determine the crack initiation time, propagation sequence, propagation speed and internal decompression process based on this. In step S1, the fiber optic grating sensor is deployed at the following locations: on the vertical line connecting the boreholes, at the midpoint of the line connecting two boreholes, and near the free surface of the concrete specimen, for monitoring the initiation, penetration, and surface opening of cracks. In step S1, the concrete specimen includes a reinforcing cage and a cubic concrete structure cast in the reinforcing cage. The cubic concrete structure has four blast holes that extend downward from the top and are distributed in a rectangular pattern. The first fiber optic grating sensor is positioned between two adjacent boreholes and between the borehole and the free face; the second fiber optic grating sensor is an embedded fiber optic strain gauge, which is installed inside the concrete specimen. In step S5, the moment of strain jump detected for the first time is determined as the moment of crack initiation; the time interval between multiple jumps is determined as the time difference of crack propagation; and the fall-back phenomenon after the jump is determined as the process of high-pressure gas depressurization in the borehole. Before step S1, there is also a digital twin model construction step, which establishes a static blasting numerical simulation model that is completely corresponding to the geometric dimensions, material properties, borehole locations and parameters of the concrete specimen, as well as the placement of the fiber optic grating sensor. The data obtained by the method is used to construct or optimize a digital twin model of static blasting.

2. The method for testing the concrete fracture effect based on fiber optic grating measurement according to claim 1, characterized in that, In step S1, the fiber optic grating sensor includes one or more of the following: embedded fiber optic strain gauge, reusable fiber optic strain gauge, and fiber optic grating displacement gauge.

3. The method for testing the concrete fracture effect based on fiber optic grating measurement according to claim 2, characterized in that, In step S1, the embedded fiber optic strain gauge is tied and fixed to the reinforcing steel frame before the concrete specimen is poured; the reusable fiber optic strain gauge and fiber optic displacement gauge are fixed to the surface of the concrete specimen by epoxy resin adhesive or mechanical clamps.

4. The method for testing the concrete fracture effect based on fiber optic grating measurement according to claim 1, characterized in that, In step S3, the fiber optic sensor analyzer is a multi-channel analyzer that supports high-frequency synchronous data acquisition from multiple sensors at frequencies above 25Hz or 100Hz.

5. The method for testing the concrete fracture effect based on fiber optic grating measurement according to claim 1, characterized in that, The crack initiation time, propagation rate, and decompression process data obtained in step S5 are used to calibrate the rock constitutive model parameters and the static fracturing agent expansion pressure time history curve parameters in the static blasting numerical simulation.

6. The method for testing the concrete fracture effect based on fiber optic grating measurement according to claim 5, characterized in that, The calibration process is an iterative closed-loop process. The calibrated digital twin model is used to predict the blasting effect under new working conditions. The prediction results are verified and fed back again through the methods in steps S1 to S5, thereby realizing the continuous self-optimization of the model.

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