Method and system for monitoring and analyzing static rock breaking process of shallow water reef

Abstract

The invention relates to the technical field of underwater blasting, in particular to a monitoring analysis method and system for the static rock breaking process of shallow water reefs, and the method comprises the steps: obtaining a strain time travel curve and a displacement time travel curve monitored by a fiber grating sensor; analyzing the strain time history curve and the displacement time history curve so as to judge the aging process of crack generation, expansion and medium splitting in the reef or concrete medium in the hydration reaction process; the fiber bragg grating sensing technology is introduced into the field of underwater static rock breaking, the invisible internal damage process is converted into quantifiable and interpretable data through real-time monitoring and data intelligent analysis, transparency of the construction process is achieved, and a decisive basis is provided for accurately judging the construction end point and optimizing technological parameters; and the whole process is free of explosive shock waves, obvious vibration and flying stones, and is particularly suitable for underwater construction in blasting sensitive areas.

Description

Technical Field

[0001] This invention relates to the field of underwater blasting technology, and more specifically to a method and system for static rock breaking with large apertures in shallow water reefs. Background Technology

[0002] Underwater blasting technology is widely used in waterway dredging, port construction, and the demolition of underwater structures. Currently, the main underwater rock-breaking methods include explosive blasting and static fracturing techniques. While explosive blasting is highly efficient, it generates strong shock waves, ground vibrations, and noise in the underwater environment, posing a serious safety threat to nearby sensitive facilities. Furthermore, its use, transportation, and storage are strictly regulated, and the approval process is complex.

[0003] Static fracturing technology, as a non-explosive method, utilizes the expansion pressure generated by the hydration reaction of the fracturing agent to break the medium, theoretically possessing safety advantages such as no vibration, no flying debris, and no shock waves. However, current research and applications of static fracturing technology are mostly concentrated in terrestrial environments and small-aperture conditions.

[0004] Conventional plugging devices are difficult to use effectively underwater, leading to water intrusion or slurry loss. Changing the key water-cement ratio can significantly reduce expansion pressure and even cause reaction failure. Furthermore, as the orifice diameter increases, the large amount of water vapor generated by the hydration reaction of the fracturing agent makes blowout more likely, causing slurry to eject from the orifice, resulting in premature pressure release and fracturing failure. It is precisely because the blowout problem is difficult to solve that the application of large-diameter static fracturing technology in underwater engineering has long been considered a technically forbidden area.

[0005] Furthermore, existing technologies for monitoring and evaluating the rock-breaking process are severely lagging behind, whether for traditional blasting or static fracturing. Currently, the common practice is to rely on post-experimental observation (such as underwater exploration by divers or sonar scanning) to determine whether the rock has broken. This method cannot reflect the dynamic process of crack generation, propagation, and penetration in real time. The lack of effective process monitoring means that the construction process is in a black box, making it impossible to accurately determine the breaking endpoint, hindering refined management and quality control, and failing to provide real-time data support for optimizing process parameters. Summary of the Invention

[0006] To address the technical problems existing in shallow-water reef blasting, the first aspect of this invention proposes a technical solution: a method for monitoring and analyzing the static rock-breaking process of shallow-water reefs, comprising: Acquire strain time history curves and displacement time history curves monitored by fiber Bragg grating sensors; The strain time history curves and displacement time history curves were analyzed to determine the aging process of crack initiation, propagation, and media splitting in the reef or concrete medium during the hydration reaction. The analysis includes: Crack initiation identification: When the first steep jump appears on the strain time history curve or displacement time history curve, it is determined that the first macroscopic crack in the medium has been generated. Identifying crack propagation: When the curve shows one or more consecutive jumps after the first jump, it is determined that a new crack has been generated or an existing crack has further propagated; if the curve falls back after the jump, it is determined that a water vapor decompression process has occurred within the crack. Identifying media splitting: When the curve reaches a stable high-level platform after the last jump and no longer undergoes drastic changes, it is determined that the medium has been completely split and the breaking process is basically over. The criteria for determining the sudden jump are: within a set unit time, the rate of change of the strain time history curve or displacement time history curve exceeds a preset threshold.

[0007] Preferably, the fiber optic grating sensor includes an embedded strain gauge and a displacement gauge, wherein the displacement gauge measures displacement deformation by means of a telescopic probe or a pull wire.

[0008] Preferably, the static rock-breaking process includes drilling blast holes in the reef or concrete medium in shallow water, wherein the diameter of the blast holes is greater than 50 mm.

[0009] Preferably, the diameter of the borehole is 100~114mm.

[0010] Preferably, the diameter of the borehole is 114 mm; the diameter is determined and selected using the following experimental method: S1A. Select the first group of boreholes, with diameters of 40mm, 100mm and 114mm respectively; S1B. In each borehole of diameter, static fracturing agent is filled under the same conditions of filling density of 1.91 g / cm³ and water-cement ratio of 0.3. S1C: Use a pressure sensor with a range of not less than 150MPa to measure the expansion pressure time history curve, and use a thermocouple with a temperature range of not less than 250℃ to measure the reaction temperature time history curve. S1D. Obtain the final stable pressure value from the expansion pressure time history curve, and obtain the highest reaction temperature value from the reaction temperature time history curve. S1E, the screening criteria are: the minimum pore size with a final stable pressure of not less than 80 MPa and a maximum reaction temperature of not less than 150 °C; according to experimental data, the pore size that meets this standard is 114 mm.

[0011] Preferably, the spacing between adjacent blast holes is 30~40cm.

[0012] Preferably, the spacing between adjacent boreholes is set to 35cm; the spacing is optimized using the following numerical simulation method: S1a. Establish a plane strain model of rock medium containing two boreholes. The model parameters are set as follows: tensile strength of medium 8MPa, elastic modulus 100GPa, Poisson's ratio 0.3, borehole diameter 114mm. S1b. Apply a uniformly distributed pressure of 100 MPa to the inner wall of the borehole to simulate the expansion load of the static fracturing agent. S1c. Using the extended finite element method, the working conditions with hole spacing of 30cm, 35cm and 40cm were simulated respectively, and the stress distribution and crack propagation path of the model were calculated. S1d, the criterion is: the maximum hole spacing between two boreholes that can generate at least one through crack under the 100MPa load; according to the simulation results, the hole spacing that meets this criterion is 35cm.

[0013] Preferably, the static rock breaking process includes utilizing the existing initial cracks and free surfaces in the reef medium during hole placement, causing the cracks to propagate in the direction of the initial cracks and free surfaces.

[0014] Preferably, the static rock breaking process includes filling the borehole with slurry through a sealing and plugging device. The sealing and plugging device includes an inner plate, an outer plate, a silicone sealing sleeve disposed between the inner plate and the outer plate, and a steel bar passing through the inner plate, the outer plate, and the silicone sealing sleeve along the axial direction of the inner plate and the outer plate. The inner plate and the outer plate are fixed to the steel bar, so that the silicone sealing sleeve has a fixed length and is used to accommodate the slurry. The radial expansion pressure generated by the hydration reaction of the slurry causes the silicone sealing sleeve to expand outward and press against the inner wall of the borehole.

[0015] The second aspect of this invention proposes a technical solution: a monitoring and analysis system for the static rock-breaking process of shallow-water reefs, characterized in that the system, used to implement the above-mentioned method, comprises: Data acquisition module: includes a fiber optic grating sensor group arranged on the reef or concrete medium. The sensor group includes at least a fiber optic strain gauge for monitoring strain and a fiber optic displacement gauge for monitoring displacement, for acquiring strain time history data and displacement time history data during the static rock breaking process. Signal demodulator: connected to the fiber optic grating sensor group, used to convert the acquired optical signals into electrical signals and output strain time history curves and displacement time history curves; Data analysis module: Communicatively connected to the signal demodulator, configured to execute the following analysis procedures: Identify the first steep jump on the strain time history curve or displacement time history curve, and generate a judgment signal for the first macroscopic crack. The system identifies one or more consecutive jumps that occur after the initial jump and generates a judgment signal indicating the generation of a new crack or the propagation of an existing crack; if a curve drop is detected after a jump, a judgment signal indicating that water vapor decompression has occurred within the crack is generated. The identification curve reaches a stable high platform after the final jump, and generates a judgment signal that the medium has been completely split and the breaking process has basically ended. The criteria for determining the sudden jump are: within a set unit time, the rate of change of the strain time history curve or displacement time history curve exceeds a preset threshold.

[0016] Compared with the prior art, the advantages of the present invention are as follows: Process visibility and controllability: This application introduces fiber optic grating sensing technology into the field of underwater static rock breaking. Through real-time monitoring and intelligent data analysis, the invisible internal destruction process is transformed into quantifiable and interpretable data, realizing the transparency of the construction process and providing a decisive basis for accurately judging the construction endpoint and optimizing process parameters. High safety: The entire process is free of explosive shock waves, significant vibrations, and flying rocks, making it particularly suitable for underwater construction in blasting-sensitive areas, resulting in significant social and environmental benefits; Excellent crushing effect: By adopting an optimized large-diameter hole and a special sealing device, high expansion pressure is achieved, and the hole layout is optimized by numerical simulation, which reduces the number of holes and lowers costs while ensuring the effect. High reliability: The balance bar type sealing and plugging device effectively solves the two core problems of underwater sealing and blowhole, ensuring the successful application of large-diameter static crushing technology in underwater environments. Attached Figure Description

[0017] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the sealing and plugging device in an embodiment of the present invention being installed in a reef or concrete medium; Figure 2 This is a schematic diagram of the sealing and plugging device shown in the embodiment of the present invention; Figure 3 This is a schematic diagram of the grouting holes on the outer and inner surfaces of the sealing and plugging device shown in the embodiment of the present invention; Figure 4a This is the pressure time history curve for a borehole diameter of 40mm in this embodiment of the invention; Figure 4b This is the pressure time history curve for a borehole diameter of 100mm in this embodiment of the invention; Figure 4c This is the pressure time history curve for a borehole diameter of 114 mm in this embodiment of the invention; Figure 5a This is the temperature time history curve for a borehole diameter of 40mm in this embodiment of the invention; Figure 5b This is the temperature time history curve for a borehole diameter of 100mm in this embodiment of the invention; Figure 5c This is the temperature time history curve for a borehole diameter of 114 mm in this embodiment of the invention; Figure 6a This is a schematic diagram of crack propagation obtained from the numerical simulation of the stress cloud map when the borehole spacing is 30cm in an embodiment of the present invention; Figure 6b This is a schematic diagram of crack propagation obtained from the numerical simulation of the stress cloud map when the borehole spacing is 35cm in an embodiment of the present invention; Figure 6c This is a schematic diagram of crack propagation obtained from the numerical simulation of the stress cloud map when the borehole spacing is 40cm in an embodiment of the present invention; Figure 6d This is a schematic diagram of the crack propagation length versus time for different hole spacings in an embodiment of the present invention; Figure 7 This is the strain-time history curve detected by a fiber optic grating sensor placed on the surface of a concrete specimen in an embodiment of the present invention. Detailed Implementation

[0018] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0019] The proposed scheme for static rock breaking and monitoring analysis of shallow reefs with large apertures includes three parts: a static rock breaking method for shallow reefs with large apertures, a static rock breaking and monitoring analysis method for shallow reefs with large apertures, and a static rock breaking and monitoring analysis system for shallow reefs with large apertures. The static rock breaking method for shallow reefs with large apertures is the basis for implementing the static rock breaking and monitoring analysis method.

[0020] Combination Figure 1 and Figure 2 As shown, the shallow water reef large-aperture static rock breaking method includes: Step S1: Drill blast holes in the reefs or concrete in the shallow water area. The diameter of the blast holes should be greater than 50 mm. Step S2: Mix the static crushing agent with water at a predetermined water-cement ratio to form a slurry; Step S3: Fill the borehole with slurry through the sealing and plugging device. The sealing and plugging device can fit tightly against the inner wall of the borehole when the slurry hydration reaction generates expansion pressure, thereby achieving underwater sealing and preventing blowout. Step S4: The static fracturing agent undergoes a hydration reaction in the sealed borehole, generating an expansion pressure of no less than 30 MPa, causing cracks to form in the reef or concrete medium and propagate until it breaks.

[0021] It should be understood that the blast holes are set on the free side of the reef. 20a represents the rock on the original free side, 20b represents the rock that was crushed after static rock breaking, 21 represents the stress direction, and 22 represents the crack generated during static blasting. Static rock breaking of shallow water reefs is achieved in this way.

[0022] In an optional embodiment, in step S1, the diameter of the borehole is 100~138mm.

[0023] In step S1, the diameter of the borehole is 114 mm; the diameter is determined and screened using the following experimental method: S1A. Select the first group of boreholes, with diameters of 40mm, 100mm and 114mm respectively; S1B. In each borehole of diameter, static fracturing agent is filled under the same conditions of filling density of 1.91 g / cm³ and water-cement ratio of 0.3. S1C: Use a pressure sensor with a range of not less than 150MPa to measure the expansion pressure time history curve, and use a thermocouple with a temperature range of not less than 250℃ to measure the reaction temperature time history curve. S1D: Obtain the final stable pressure value from the expansion pressure time history curve, and obtain the highest reaction temperature value from the reaction temperature time history curve; S1E, the screening criteria are: the minimum pore size with a final stable pressure of not less than 80 MPa and a maximum reaction temperature of not less than 150 °C; according to experimental data, the pore size that meets this standard is 114 mm.

[0024] In existing technologies, increasing the orifice diameter usually exacerbates the risk of nozzle leakage and leads to technical failure. However, this invention overcomes this bottleneck by using a dedicated sealing and plugging device, thereby enabling in-depth research on the impact of orifice diameter on mechanical properties.

[0025] Specifically, excluding nozzle interference, and controlling other variables (filling density 1.91 g / cm³, water-cement ratio 0.3), the effects of different pore sizes (40 mm, 100 mm, 114 mm) on the two key performance indicators of final expansion pressure and maximum reaction temperature were quantitatively studied. Figures 4a to 4c as well as Figures 5a to 5cAs shown, through the analysis of pressure and temperature data, within a certain range, increasing the aperture does not reduce performance. On the contrary, due to the larger reaction system and more significant heat accumulation, a sudden increase in expansion pressure and reaction temperature occurs. By setting clear performance thresholds (pressure ≥80MPa, temperature ≥150℃), the optimal aperture of 114mm, which can meet the requirements of high-strength crushing and has the highest construction efficiency, was objectively selected from a series of apertures.

[0026] This quantitative method ensures the repeatability and optimization of the technical solution, avoiding the blind selection of parameters.

[0027] in, Figure 4a There are almost no stress mutations in it. Figure 4b The time for the sudden change in pressure is less than 5000 seconds, while Figure 4c The time for the sudden change in pressure is 60 minutes, or about 3600 seconds. Figure 4a The maximum pressure is 30 MPa. Figure 4b The maximum pressure is 170 MPa. Figure 4c The maximum pressure is 200 MPa. It can be seen that the larger the pore size, the greater the expansion pressure generated by the static fracturing agent after hydration reaction. Moreover, the larger the pore size, the faster the reaction rate, and the shorter the time it takes for the expansion pressure acting on the pore wall to reach a stable value.

[0028] Combination Figures 5a to 5c The temperature-time history curves for three different apertures show that the maximum reaction temperature increases continuously with the increase of aperture. This means that the larger the aperture, the more vigorous the hydration reaction of the static fracturing agent, which is consistent with the performance of the pressure-time history curves.

[0029] Furthermore, in step S1, the spacing between adjacent blast holes is 30~40cm.

[0030] Specifically, in step S1, the hole spacing between adjacent boreholes is set to 35cm; the hole spacing is optimized using the following numerical simulation method: S1a. Establish a plane strain model of rock medium containing two boreholes. The model parameters are set as follows: tensile strength of medium 8MPa, elastic modulus 100GPa, Poisson's ratio 0.3, borehole diameter 114mm. S1b. Apply a uniformly distributed pressure of 100 MPa to the inner wall of the borehole to simulate the expansion load of the static fracturing agent. S1c. Using the extended finite element method, the working conditions with hole spacing of 30cm, 35cm and 40cm were simulated respectively, and the stress distribution and crack propagation path of the model were calculated. S1d, the criterion is: the maximum hole spacing that can produce at least one through crack between two boreholes under a load of 100MPa; according to the simulation results, the hole spacing that meets this criterion is 35cm.

[0031] Thus, through numerical simulation based on fracture mechanics, the above hole spacing parameter was determined to be 35cm.

[0032] Specifically, the optimization process includes four steps: model building, load application, simulation analysis, and result determination.

[0033] Model establishment: Based on the theory of elasticity, a two-dimensional numerical model containing two boreholes was established, and parameters consistent with the actual mechanical properties of the reef (tensile strength 8MPa, elastic modulus 100GPa, etc.) were set.

[0034] Load application: The complex expansion process of the static fracturing agent is simplified to a uniformly distributed static load of 100MPa applied to the borehole wall, which is consistent with its quasi-static action characteristics.

[0035] Simulation Analysis: An advanced extended finite element method (EPM) is employed, which can efficiently simulate the initiation and propagation of discontinuous cracks. Crack propagation is simulated under three hole spacings: 30cm, 35cm, and 40cm. Figures 6a to 6c As shown.

[0036] Result determination: such as Figures 6a to 6c As shown, the simulation results indicate that although a hole spacing of 30cm can form two cracks, the number of holes is too large; a hole spacing of 40cm cannot form a through crack, resulting in failure to break; and a hole spacing of 35cm is the maximum hole spacing that can form at least one through crack.

[0037] Furthermore, such as Figure 6d As shown, the crack propagation length curve further verifies the effectiveness of the 35cm hole spacing.

[0038] Thus, through numerical simulation analysis based on fracture mechanics, the blasting effect can be predicted before construction, greatly reducing the risk and cost of failure in field tests.

[0039] Furthermore, in step S1, when creating holes, the existing initial cracks and free surfaces in the rock medium are utilized to propagate the cracks in the direction of the initial cracks and free surfaces. In this way, the natural defects of the rock medium can be utilized.

[0040] It should be understood that the initial crack and the free surface are the weakest links in the medium, with the lowest tensile strength. Under the action of expansion pressure, the crack will preferentially propagate towards these areas, guiding the cracks rather than forcibly breaking them. This can significantly reduce the required expansion pressure and improve the controllability of crack propagation direction and breaking efficiency.

[0041] Preferably, in step S2, the predetermined water-cement ratio is 0.3.

[0042] It should be understood that the water-cement ratio is a key factor affecting the expansion pressure and the fluidity of the slurry.

[0043] If the water-cement ratio is too low, the slurry will be dry and the filling will not be dense; if it is too high, the expansion pressure will decrease significantly. Through the inventor's previous experiments, a water-cement ratio of 0.3 is the key parameter to achieve the best balance between high expansion pressure and good workability, ensuring that the slurry can fill smoothly to the bottom of the hole while generating enough expansion force to break the reef.

[0044] Furthermore, in combination Figure 2 As shown, in step S3, the underwater sealing and plugging device includes an inner plate 2, an outer plate 3, a silicone sealing sleeve 4 disposed between the inner plate 2 and the outer plate 3, and a steel bar 1 that passes through the inner plate 2, the outer plate 3, and the silicone sealing sleeve 4 along the axial direction of the inner plate 2 and the outer plate 3. The inner plate 2 and the outer plate 3 are fixed to the steel bar 1.

[0045] Specifically, the underwater sealing and plugging device has two ends, each of which includes an inner plate 2, an outer plate 3, and a silicone sealing sleeve 4. A steel bar 1 connects the two ends, and the inner plate 2 and outer plate 3 of the two ends are fixed to the surface of the steel bar 1 by a steel pin 8 and a nut 7, so that the two ends have a fixed axial distance from each other.

[0046] Furthermore, a non-woven bag 5 is provided between the silicone sealing sleeve 4 and the inner plate 2, and the inside of the non-woven bag 5 is used to contain the slurry.

[0047] Specifically, in combination Figure 2 and Figure 3 As shown, grouting holes are provided at the ends of the underwater sealing and plugging device, namely the end face of the outer plate 3, the end face of the silicone sealing sleeve 4, and the end face of the inner plate 2. The outer plate 3 and the inner plate 2 can rotate relative to each other. When the openings of the outer plate 3, the silicone sealing sleeve 4, and the inner plate 2 are aligned, grout can be injected into the inside of the nonwoven bag 5 through the opening. After the grout is filled, the outer plate 3 is rotated so that the first grouting hole 10a of the outer plate 3 and the second grouting hole 10b of the inner plate 2 are staggered, so that the grout will no longer leak or depressurize at this grouting hole.

[0048] in, Figure 3 The arrow in the image indicates that the outer disk 3 rotates in the direction of the arrow, so that the first grouting hole 10a of the outer disk 3 and the second grouting hole 10b of the inner disk 2 change from an aligned state to an interleaved state.

[0049] It should be understood that static fracturing relies on the enormous radial expansion pressure generated by the hydration reaction of the fracturing agent to crack rock or concrete. Theoretically, the larger the aperture and the more fracturing agent loaded, the greater the total expansion force and the higher the fracturing efficiency. However, while the expansion force compresses the target medium in all directions, it also seeks release at both ends of the borehole (especially the orifice). Under traditional simple plugging methods, this axial pressure can easily lead to blowout, i.e., the plugging material is instantly ejected, causing blasting failure and safety accidents. Therefore, to ensure safety, engineering practice often forces the adoption of a strategy of reducing the borehole diameter. Although reducing the aperture decreases the total expansion force and temporarily relieves the sealing pressure, the cost is a significant reduction in the pressure acting on the target medium, greatly diminishing the fracturing effect. Often, more and denser boreholes are needed to complete the task, which is time-consuming and labor-intensive.

[0050] The device shown in this application is characterized by: First, the device rigidly connects all internal components—the inner discs 2 and outer discs 3 at both ends, and the silicone sealing sleeves 4—into a single frame via a through-through steel bar 1 and nuts 7 locking at both ends. This frame forms a closed force-bearing ring in the axial direction. When the fracturing agent reacts and generates an upward thrust, this force is transmitted through the top component to the steel bar 1, and then directly to the bottom component via the steel bar 1, transforming into a downward constraint force. In this way, the axial force generated inside the device is canceled and balanced within its own frame, eliminating the force that would push the entire device out of the hole, allowing the device to remain stably in the hole and firmly lock the energy inside.

[0051] Secondly, the breaking agent sealed within the silicone sealing sleeve 4 and the non-woven bag 5, unable to counteract its radial expansion force, can only squeeze the soft silicone sleeve outward. Under high pressure, the silicone sleeve undergoes elastic deformation, continuously bulging outward, thus actively and more tightly adhering to the inner wall of the borehole. The greater the pressure, the tighter the adhesion; the tighter the adhesion, the more exponentially the frictional force increases.

[0052] Third, when the grouting holes on the outer disk 3, inner disk 2 and silicone sealing sleeve 4 are aligned at a specific position, grout can be injected. After the injection is completed, the outer disk 3 can be rotated to offset the grouting holes and achieve mechanical one-way valve locking. This is conducive to making the device convenient and efficient during filling and absolutely sealed during operation.

[0053] As described above, the device shown in this application can be applied to large-diameter static blasting without reducing the borehole diameter or the expansion pressure acting on the target medium. Tests have shown that the device can play a very good role in plugging and sealing holes for large-diameter static blasting technology. Currently, it can achieve a borehole diameter of 114mm, which greatly increases the expansion pressure acting on the target medium, reduces the number of holes per unit area, and achieves a better blasting effect.

[0054] As described above, in step S4, the monitoring and analysis method for the static rock-breaking process of shallow-water reefs includes: The strain time history curves and displacement time history curves are monitored by fiber optic grating sensors, and the aging history of crack generation, propagation and media splitting in the reef or concrete medium during the hydration reaction is analyzed and determined. The fiber optic grating sensors can be arranged on the surface of the reef or concrete medium sample.

[0055] Combination Figure 7 As shown, the analysis methods include: S41. Identifying crack initiation: When the first steep jump appears on the strain time history curve or displacement time history curve, it is determined that the first macroscopic crack in the medium has been generated. S42. Identify crack propagation: When the curve shows one or more consecutive jumps after the first jump, it is determined that a new crack has been generated or the original crack has further propagated; if the curve falls back after the jump, it is determined that a water vapor decompression process has occurred in the crack. S43. Identifying media splitting: When the curve reaches a stable high-level platform after the final jump and no longer undergoes drastic changes, it is determined that the medium has been completely split and the breaking process is basically over.

[0056] The criteria for determining a sudden jump are: within a set unit time period, the rate of change of the strain time history curve or displacement time history curve exceeds a preset threshold.

[0057] In an optional embodiment, during the initial stage of the static fracturing agent hydration reaction (e.g., the first 10 minutes), the system collects strain / displacement data and calculates its average background noise level and standard deviation. The trigger threshold for the jump is set to K times the background noise amplitude (e.g., K = 5~10), or an absolute rate of change threshold is set (e.g., a strain rate of change greater than 100 microstrains / second, or a displacement rate of change greater than 0.1 mm / second).

[0058] Specifically, the instantaneous slope (first derivative) of the curve within a sliding time window (e.g., a 2-second window) is calculated in real time. When the absolute value of the instantaneous slope continuously exceeds the above-mentioned set threshold for a preset duration (e.g., lasting more than 1 second), it is determined that a jump has occurred near that time point. The time and magnitude of the jump are recorded and associated with subsequent curve fallback, plateau and other features for the purpose of executing the crack state determination process.

[0059] As mentioned above, this application transforms the invisible internal failure process into quantifiable and interpretable data by analyzing the characteristics of sudden jumps, falls, and plateaus on the strain / displacement time history curve. The sudden jumps correspond to crack generation, proving the staged nature of the process. The falls reveal the microscopic mechanism of water vapor depressurization, deepening the understanding of the process principle. The plateau marks the completion of crushing and can be used to accurately determine the end point of construction.

[0060] In an optional embodiment, the fiber Bragg grating sensor includes an embedded strain gauge and a displacement gauge, the displacement gauge measuring displacement deformation by means of a telescopic probe or a pull wire.

[0061] Furthermore, a monitoring and analysis system for the static rock-breaking process of shallow reefs is provided to implement the above method. The system includes a data acquisition module, a signal demodulator, and a data analysis module.

[0062] Specifically, the data acquisition module includes a fiber optic grating sensor group arranged on the reef or concrete medium. The sensor group includes at least a fiber optic strain gauge for monitoring strain and a fiber optic displacement gauge for monitoring displacement, for acquiring strain time history data and displacement time history data during the static rock breaking process.

[0063] Optionally, the data acquisition module includes arranging fiber Bragg grating sensor arrays on (or pre-embedded within) the surface of the reef or concrete medium that needs to be broken. In this embodiment, fiber Bragg grating strain gauges are attached to the central area of ​​the borehole connection line and near the possible free surface, and fiber Bragg grating displacement gauges are set at key locations. These displacement gauges contact the medium surface via telescopic probes.

[0064] The signal demodulator is connected to the fiber optic grating sensor group and is used to convert the acquired optical signals into electrical signals and output strain time history curves and displacement time history curves.

[0065] The signals from the fiber optic cables of the fiber Bragg grating sensor are collected and connected to a signal demodulator (such as the SM125 fiber Bragg grating demodulator) on shore or on the work vessel. This demodulator converts the optical wavelength signals into digital electrical signals, namely strain time history curves and displacement time history curves, in real time at a sampling frequency of 1Hz, and transmits the data stream to the data analysis module in real time via an Ethernet interface.

[0066] The data analysis module is communicatively connected to the signal demodulator and is configured to execute the following analysis procedure according to the monitoring and analysis method for the static rock-breaking process of shallow reefs described above: Identify the first steep jump on the strain time history curve or displacement time history curve, and generate a judgment signal for the first macroscopic crack. The system identifies one or more consecutive jumps that occur after the initial jump and generates a judgment signal indicating the generation of a new crack or the propagation of an existing crack; if a curve drop is detected after a jump, a judgment signal indicating that water vapor decompression has occurred within the crack is generated. The identification curve reaches a stable high platform after the final jump, and generates a judgment signal that the medium has been completely split and the breaking process has basically ended. The criteria for determining a sudden jump are: within a set unit time period, the rate of change of the strain time history curve or displacement time history curve exceeds a preset threshold.

[0067] Specifically, the data analysis module can be an industrial computer equipped with dedicated analysis software. This software incorporates an analysis algorithm based on a monitoring and analysis method for the static rock-breaking process of shallow-water reefs.

[0068] Real-time analysis process: The software receives and displays strain and displacement curves in real time. Operators can set thresholds, or the software can intelligently identify curve characteristics. When the software detects the first steep jump on the curve (such as...) Figure 7 At time t1, an alert immediately pops up on the operation interface and logs are recorded: the first macroscopic crack has been detected.

[0069] Subsequently, after time t1, the curve exhibited several consecutive jumps ( Figure 7 At times t2 and t3, the software determined that the crack was rapidly propagating, and observed the curve falling back after the sudden jump ( Figure 7 After t2), the water vapor depressurization that occurs within the crack is recorded synchronously.

[0070] When the curve passes the final jump ( Figure 7 After time t4, the medium enters a stable high-level platform and there are no more violent fluctuations within a certain time window (such as 10 minutes). The software determines that the medium has been completely split, the crushing process ends, and a construction completion signal is issued.

[0071] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for monitoring and analyzing the static rock-breaking process of shallow-water reefs, characterized in that, include: Obtain the strain time history curves and displacement time history curves monitored by the fiber Bragg grating sensor. The strain time history curves and displacement time history curves were analyzed to determine the aging process of crack initiation, propagation, and media splitting in the reef or concrete medium during the hydration reaction. The analysis includes: Crack initiation identification: When the first steep jump appears on the strain time history curve or displacement time history curve, it is determined that the first macroscopic crack in the medium has been generated. Identifying crack propagation: When the curve shows one or more consecutive jumps after the first jump, it is determined that a new crack has been generated or an existing crack has further propagated; if the curve falls back after the jump, it is determined that a water vapor decompression process has occurred within the crack. Identifying media splitting: When the curve reaches a stable high-level platform after the last jump and no longer undergoes drastic changes, it is determined that the medium has been completely split and the breaking process is basically over. The criteria for determining the sudden jump are: within a set unit time, the rate of change of the strain time history curve or displacement time history curve exceeds a preset threshold.

2. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 1, characterized in that, The fiber optic grating sensor includes an embedded strain gauge and a displacement gauge, wherein the displacement gauge measures displacement deformation by means of a telescopic probe or a pull wire.

3. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 1, characterized in that, The static rock-breaking process includes drilling blast holes in the reef or concrete medium in shallow water, the diameter of which is greater than 50 mm.

4. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 3, characterized in that, The diameter of the borehole is 100~114mm.

5. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 3, characterized in that, The diameter of the borehole is 114 mm; the diameter was determined and screened using the following experimental method: S1A. Select the first group of boreholes, with diameters of 40mm, 100mm and 114mm respectively; S1B. In each borehole of diameter, static fracturing agent is filled under the same conditions of filling density of 1.91 g / cm³ and water-cement ratio of 0.

3. S1C: Use a pressure sensor with a range of not less than 150MPa to measure the expansion pressure time history curve, and use a thermocouple with a temperature range of not less than 250℃ to measure the reaction temperature time history curve. S1D. Obtain the final stable pressure value from the expansion pressure time history curve, and obtain the highest reaction temperature value from the reaction temperature time history curve. S1E, the screening criteria are: the minimum pore size with a final stable pressure of not less than 80 MPa and a maximum reaction temperature of not less than 150 °C; according to experimental data, the pore size that meets this standard is 114 mm.

6. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 3, characterized in that, The distance between adjacent blast holes is 30~40cm.

7. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 6, characterized in that, The spacing between adjacent boreholes is set to 35cm; this spacing is optimized using the following numerical simulation method: S1a. Establish a plane strain model of rock medium containing two boreholes. The model parameters are set as follows: tensile strength of medium 8MPa, elastic modulus 100GPa, Poisson's ratio 0.3, borehole diameter 114mm. S1b. Apply a uniformly distributed pressure of 100 MPa to the inner wall of the borehole to simulate the expansion load of the static fracturing agent. S1c. Using the extended finite element method, the working conditions with hole spacing of 30cm, 35cm and 40cm were simulated respectively, and the stress distribution and crack propagation path of the model were calculated. S1d, the criterion is: the maximum hole spacing between two boreholes that can generate at least one through crack under the 100MPa load; according to the simulation results, the hole spacing that meets this criterion is 35cm.

8. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 1, characterized in that, The static rock breaking process involves utilizing the existing initial cracks and free surfaces in the reef medium during hole placement, causing the cracks to propagate in the direction of the initial cracks and free surfaces.

9. The monitoring and analysis method for the static rock-breaking process of shallow-water reefs according to claim 1, characterized in that, The static rock breaking process includes filling the blast hole with slurry through a sealing and plugging device. The sealing and plugging device includes an inner plate (2), an outer plate (3), a silicone sealing sleeve (4) set between the inner plate (2) and the outer plate (3), and a steel bar (1) passing through the inner plate (2), the outer plate (3), and the silicone sealing sleeve (4) along the axial direction of the inner plate (2) and the outer plate (3). The inner plate (2) and the outer plate (3) are fixed to the steel bar (1). A nonwoven bag (5) is placed between the silicone sealing sleeve (4) and the inner plate (2), and the inside of the nonwoven bag (5) is used to hold the slurry. The end face of the outer disc (3), the end face of the silicone sealing sleeve (4) and the end face of the inner disc (2) are all provided with grouting holes. The outer disc (3) and the inner disc (2) can rotate relative to each other. When the outer disc (3) and the inner disc (2) rotate to align with the grouting holes, grout can be injected into the non-woven bag (5). When the outer disc (3) and the inner disc (2) rotate to intersect the grouting holes, the grout is sealed inside the non-woven bag (5). The radial expansion pressure generated by the hydration reaction of the slurry causes the silicone sealing sleeve (4) to expand outward and press against the inner wall of the borehole.

10. A monitoring and analysis system for the static rock-breaking process of shallow-water reefs, characterized in that, The system for implementing the method of claim 1 includes: Data acquisition module: includes a fiber optic grating sensor group arranged on the reef or concrete medium. The sensor group includes at least a fiber optic strain gauge for monitoring strain and a fiber optic displacement gauge for monitoring displacement, for acquiring strain time history data and displacement time history data during the static rock breaking process. Signal demodulator: connected to the fiber optic grating sensor group, used to convert the acquired optical signals into electrical signals and output strain time history curves and displacement time history curves; Data analysis module: Communicatively connected to the signal demodulator, configured to execute the following analysis procedures: Identify the first steep jump on the strain time history curve or displacement time history curve, and generate a judgment signal for the first macroscopic crack. The system identifies one or more consecutive jumps that occur after the initial jump and generates a judgment signal indicating the generation of a new crack or the propagation of an existing crack; if a curve drop is detected after a jump, a judgment signal indicating that water vapor decompression has occurred within the crack is generated. The identification curve reaches a stable high platform after the final jump, and generates a judgment signal that the medium has been completely split and the breaking process has basically ended. The criteria for determining the sudden jump are: within a set unit time, the rate of change of the strain time history curve or displacement time history curve exceeds a preset threshold.

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