Combined rebound apparatus, point load's dangerous rock mass comprehensive monitoring and early warning method and system

Abstract

This invention relates to the field of unstable rock mass stability monitoring and early warning technology, specifically to a comprehensive monitoring and early warning method and system for unstable rock masses combining rebound hammers and point loads. The system includes a multi-source data fusion diagnostic module that integrates the natural frequency change trend generated by the natural frequency analysis and early warning module, as well as the point load intensity index and rebound value obtained from on-site verification by the point load testing unit and rebound value testing unit, to perform collaborative analysis and diagnosis. Through diagnostic logic rules within a pre-established multi-parameter collaborative diagnostic model, the damage mode of the unstable rock mass is judged and classified. This invention, by introducing point load intensity and rebound value as key verification indicators and performing collaborative analysis with the natural frequency change trend, can effectively distinguish the root causes of the natural frequency decline. This multi-parameter collaborative diagnostic method overcomes the limitation of single-frequency monitoring methods, which can only judge stability changes but cannot identify the root causes of changes.

Description

Technical Field

[0001] This invention relates to the field of unstable rock mass stability monitoring and early warning technology, specifically to a comprehensive monitoring and early warning method and system for unstable rock masses that combines rebound hammers and point loads. Background Technology

[0002] Unstable rock masses are common geological hazards on both natural and artificial steep slopes, and their stability directly affects the safety of people's lives and property and major engineering projects. Long-term, effective monitoring of unstable rock masses and timely implementation of targeted engineering remediation measures are key and challenging aspects of geotechnical engineering disaster prevention and control.

[0003] Currently, monitoring methods based on dynamic characteristics have shown great potential in monitoring unstable rock masses, especially the natural frequency monitoring method. The principle of this method is that the natural frequency of an unstable rock mass, as a whole structure, is closely related to its stiffness, mass, and boundary conditions. When damage occurs inside or at the boundaries of the unstable rock mass, its overall stiffness decreases, leading to a drop in its natural frequency. Therefore, by continuously monitoring the changing trend of the natural frequency of the unstable rock mass, it is possible to provide early warning of its stability deterioration to a certain extent.

[0004] However, the single natural frequency monitoring method has an inherent limitation: while it can detect a decrease in the overall stiffness of the unstable rock mass, it cannot effectively distinguish the root cause of this decrease. A sustained decrease in the natural frequency of an unstable rock mass can stem from multiple complex mechanisms, such as: damage to the structural plane connecting the unstable rock mass and the parent rock, including opening, expansion, or shear slip, leading to reduced connection stiffness; deterioration of the internal strength of the rock material itself; weathering of the surface rock causing a decrease in hardness; or a combination of these damages ultimately leading to "overall deterioration" of the unstable rock mass. The remediation approaches and engineering measures for these different failure modes are completely different. If the specific damage type cannot be accurately identified during the monitoring phase, taking action based solely on a single frequency decrease can easily result in a lack of targeted remediation solutions, potentially leading to wasted resources or even missing the optimal treatment window. Therefore, there is an urgent need in this field for a comprehensive monitoring and diagnostic method that can clearly distinguish between these multiple damage modes. Summary of the Invention

[0005] The purpose of this invention is to provide a comprehensive monitoring and early warning method and system for unstable rock masses that combines rebound hammers and point loads, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a comprehensive monitoring and early warning method for unstable rock masses combining rebound hammer and point load, comprising the following steps: Acquire real-time monitoring data of the unstable rock mass, including the current natural frequency obtained through long-term monitoring and analysis using vibration sensors; In response to a significant decrease in the current inherent frequency compared to the corresponding initial reference value, the on-site verification process is triggered to obtain the point load intensity index and rebound value of the unstable rock mass during the same verification period; In this invention, when using a rebound hammer to test selected locations within a dangerous rock mass, the instrument axis is kept perpendicular to the rock surface. After applying pressure at a uniform speed, an impact is performed, and the rebound value is read and recorded. Similarly, multiple effective tests are required, and outliers are removed before calculating the average value. The purpose of this step is to directly obtain the current mechanical strength indicators of the rock material in the dangerous rock mass, providing crucial data support for subsequent diagnosis. Simultaneously, a portable point load tester is used to test in a representative area near the rebound hammer test points, on a flat rock surface. Pressure is applied to cause the rock sample to fracture, and the load value at failure and the distance between loading points are accurately recorded. The point load strength index is calculated according to specifications. To ensure data reliability, multiple tests are conducted in the same area, and the average value is taken as the characterization value for this verification. The current natural frequency variation trend, the point load intensity index, and the rebound value are input into a pre-established multi-parameter collaborative diagnostic model; The multi-parameter collaborative diagnostic model outputs damage pattern recognition results for unstable rock masses based on the following logical rules: If only the natural frequency decreases, while the point load strength index and rebound value remain stable, the damage mode is identified as structural surface damage; that is, the strength of the rock material itself has not decreased, but the weak structural surfaces between or inside the unstable rock mass and the bedrock have been damaged such as loosening or opening, resulting in a decrease in overall stiffness. If the natural frequency and rebound value decrease synchronously, while the point load strength index remains stable, the damage mode is identified as surface weathering and deterioration, indicating that the damage is mainly concentrated on the surface of the rock mass. If the natural frequency and the point load strength index decrease synchronously, while the rebound value remains stable, the damage mode is identified as internal material degradation; this indicates that the damage originates from the strength reduction of the rock material inside the unstable rock mass. If the natural frequency, point load strength index, and rebound value all decrease simultaneously, the damage mode is identified as comprehensive deterioration, indicating that the rock material has undergone strength attenuation and weathering from the inside out.

[0007] Furthermore, the specific criterion for determining whether the current natural frequency has significantly decreased compared to the corresponding initial reference value is as follows: The dynamic stability coefficient is calculated based on the current natural frequency and the initial reference natural frequency. The calculation formulas are as follows: Where K(t) represents the current dynamic stability coefficient of the unstable rock mass; f(t) represents the current natural frequency of the unstable rock mass; and f0 represents the initial reference value of the natural frequency of the unstable rock mass. When the cumulative decrease of K(t) exceeds the preset value (5%) and the trend of K(t) shows a negative slope in statistics, it is determined that the current intrinsic frequency has decreased significantly compared with its initial baseline value.

[0008] Furthermore, in the on-site verification process, the point load strength index of the unstable rock mass during the same verification period is obtained by a point load tester, and the rebound value of the unstable rock mass during the same verification period is obtained by a rebound hammer. The criteria for judging whether the point load intensity index is in a stable or declining state are as follows: compare the measured value of the point load intensity index obtained from the on-site verification with the historical benchmark value of the point load intensity index obtained during the stabilization period of the unstable rock mass. If the decline exceeds the first threshold (10%), the point load intensity index is judged to be in a declining state; otherwise, the point load intensity index is judged to be in a stable state. The criteria for judging whether the rebound value is stable or declining are as follows: compare the actual rebound value obtained from the on-site verification with the historical benchmark value of the rebound value obtained during the stable period of the unstable rock mass. If the decline exceeds the second threshold (10%), the rebound value is judged to be declining; otherwise, the rebound value is judged to be stable.

[0009] Furthermore, during the process of obtaining the point load strength index and rebound value of the dangerous rock mass in the same verification period within the on-site verification process, the location of the dangerous rock mass for verification testing by the point load tester and rebound tester must meet the following constraints: it is located outside the influence zone of the rear edge crack of the dangerous rock mass, the rock mass is intact without obvious open cracks, and the rock surface is relatively flat to facilitate safe operation.

[0010] Furthermore, the method also includes generating a comprehensive monitoring and diagnostic report containing the damage patterns of the unstable rock mass and targeted treatment suggestions based on the damage pattern identification results of the unstable rock mass. Targeted treatment recommendations for unstable rock mass damage patterns include: For structural surface damage, it is recommended to use prestressed anchor bolts (cables) for anchoring and / or grouting reinforcement of the structural surface; For internal material deterioration, it is recommended to use full-length bonded anchor bolts (cables) for deep anchoring to block factors that lead to internal deterioration; For surface weathering and deterioration, it is recommended to use wire mesh spraying for surface protection; For overall degradation, it is recommended to adopt a comprehensive treatment approach that combines anchoring and surface protection.

[0011] A comprehensive monitoring and early warning system for unstable rock masses, combining rebound hammers and point loads, includes: The multi-parameter automatic monitoring data acquisition module is used to deploy sensing and data acquisition equipment on the unstable rock mass. Specifically, it includes vibration sensors installed on or inside the unstable rock mass to collect vibration signals of the unstable rock mass under environmental excitation in real time. The natural frequency analysis and early warning module is used to receive and process the data uploaded by the multi-parameter automatic monitoring data acquisition module. By performing spectrum analysis on the obtained vibration signal, it calculates the natural frequency of the unstable rock mass. By performing trend analysis on the natural frequency, it identifies whether the natural frequency has decreased significantly compared to the corresponding initial reference value, and generates and issues an early warning signal when the natural frequency decreases significantly compared to the corresponding initial reference value. The on-site verification test module includes a point load test unit and a rebound value test unit for on-site verification. After receiving the warning signal from the natural frequency analysis and early warning module, it performs on-site tests of the point load strength index and surface rebound value at the preset safe location of the unstable rock mass and transmits the data back. The multi-source data fusion diagnostic module is used to integrate the natural frequency change trend generated by the natural frequency analysis and early warning module, as well as the point load strength index and rebound value obtained by the point load test unit and rebound value test unit on site, and perform collaborative analysis and diagnosis; and judge and classify the damage mode of the unstable rock mass through the diagnostic logic rules in the pre-established multi-parameter collaborative diagnostic model. The comprehensive report generation and feedback module is used to generate a comprehensive monitoring and diagnostic report containing the damage pattern of the dangerous rock mass and targeted treatment suggestions based on the diagnostic conclusions output by the multi-source data fusion diagnostic module, and to feed the comprehensive monitoring and diagnostic report back to the engineering design and monitoring management department to facilitate the formulation of engineering treatment plans and subsequent monitoring plans.

[0012] Furthermore, the point load testing unit is used to perform on-site testing of the point load strength index at preset safe locations of the unstable rock mass during the verification process, and to transmit the data back. The rebound value testing unit is used to perform on-site testing of the surface rebound value at a preset safe location of the dangerous rock mass during the verification process, and to transmit the data back.

[0013] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a comprehensive monitoring and early warning method for unstable rock masses that combines rebound hammers and point loads.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) This invention introduces point load strength and rebound value as key verification indicators and performs synergistic analysis with the natural frequency change trend. It can effectively distinguish the root causes of the natural frequency decline (structural surface damage, internal material deterioration, surface weathering and deterioration or overall deterioration). This multi-parameter synergistic diagnosis method overcomes the limitation of the single frequency monitoring method, which can only judge stability changes but cannot identify the root cause of the changes. It enhances the accuracy and credibility of the stability evaluation of dangerous rock masses to a certain extent. (2) Based on the accurate determination of different damage modes, the present invention can directly output targeted treatment solutions, avoiding the waste of resources caused by blind reinforcement or the safety hazards caused by insufficient treatment. (3) The diagnostic conclusions of the present invention can be fed back into the dynamic optimization of the monitoring scheme, and the focus of subsequent monitoring can be adjusted according to different damage modes, forming a precise control system for the entire life cycle of dangerous rock mass, which significantly improves the level of engineering safety assurance. (4) This invention reduces the risk of false alarms or omissions of a single parameter by cross-verifying multiple parameters, thereby enhancing the reliability of the stability evaluation results of dangerous rock masses. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the process of the integrated monitoring and early warning method for dangerous rock masses combining rebound hammer and point load according to the present invention; Figure 2 This is a schematic diagram illustrating the application scenario of the comprehensive monitoring and early warning method for unstable rock masses that combines rebound hammer and point load according to the present invention. Figure 3 This is a schematic diagram of the structure of the integrated monitoring and early warning system for unstable rock masses that combines a rebound hammer and point load according to the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figure 1 This embodiment provides detailed implementation steps for a comprehensive monitoring and early warning method for unstable rock masses using rebound hammers and point loads, as follows: High-precision micro-core pile vibration sensors were securely installed at the top of the selected potentially unstable rock mass and at the bottom of the stable bedrock. All sensors were connected to an integrated data acquisition system with automatic gain control and remote transmission capabilities. The system was set to a sampling frequency of 100 Hz to ensure complete capture of vibration signals generated by environmental excitations.

[0018] After monitoring is initiated, an initial steady-state observation period of no less than seven days will be conducted. During this period, the system will continuously collect vibration data and calculate the natural frequency of the unstable rock mass daily. The initial reference natural frequency f0 must be determined by satisfying the condition that the coefficient of variation of all daily frequency values ​​during this steady-state period is less than 5%, and the robust average value of the frequency during this period will be taken as the absolute benchmark for subsequent stability evaluation.

[0019] After the system enters the long-term automated monitoring phase, it executes the natural frequency calculation process daily at set times. First, the system retrieves the latest continuously collected ten-minute vibration data and uses the Welch-corrected periodogram method to estimate the power spectral density to suppress random noise. Specifically, the data is divided into multiple segments with a 50% overlap, and a Hanning window function is applied to each segment. Then, a fast Fourier transform is performed on each segment to obtain a periodogram. Finally, the periodograms of all segments are averaged to obtain the power spectrum of the bedrock input signal and the unstable rock mass response signal. The natural frequency of the unstable rock mass is identified by calculating the transfer function amplitude spectrum between the two signals. The frequency corresponding to the highest peak value on the transfer function amplitude spectrum curve is determined as the current natural frequency of the unstable rock mass on that day, denoted as f(t). All historical f(t) data are stored chronologically to construct a complete natural frequency time series.

[0020] To quantify stability changes, the system automatically calculates the dynamic stability coefficient based on the current natural frequency and the initial reference natural frequency. The calculation formulas involved are as follows: Where K(t) represents the current dynamic stability coefficient of the unstable rock mass; f(t) represents the current natural frequency of the unstable rock mass; and f0 represents the initial reference value of the natural frequency of the unstable rock mass. The criterion for stability deterioration is a sustained and significant downward trend in K(t). The system uses a moving average method to smooth the K(t) time series, with a moving average window length of seven days. For the smoothed series, a least squares method is used to fit a linear trend. If the slope of the fitted line is negative, and its absolute value is greater than 0.001 per day, while the statistical test p-value for this trend is less than 0.05, and the cumulative decrease in K(t) exceeds 5%, then the system determines that the stability of the unstable rock mass has significantly deteriorated and triggers an early warning signal.

[0021] Once the monitoring system determines that the stability of the unstable rock mass has significantly deteriorated based on the inherent frequency time-series data and triggers an early warning, the on-site verification test in this step is initiated. Upon arrival at the site, the primary task of the technicians is to determine the "safe location" for testing based on the area indicated by the early warning information and the on-site geological survey. This location must meet the following conditions: it must be outside the influence zone of the unstable rock mass's rear edge fissures, the rock mass must be intact without obvious open cracks, and the rock surface must be relatively flat to facilitate safe operation.

[0022] Rebound Value Test: A rebound value test is conducted at a designated safe location to quickly assess the hardness of the unstable rock mass surface. Using a rebound hammer calibrated on a standard steel anvil, 16 test points are evenly distributed within a predefined 200cm × 200cm test area using an orthogonal grid method. During operation, the instrument axis is kept perpendicular to the rock surface, and pressure is applied at a uniform speed to deliver the impact. The rebound value at each test point is recorded. After 16 impacts, the three highest and three lowest values ​​are removed from the measured values, and the arithmetic mean of the remaining 10 rebound values ​​is calculated as the rebound value R for the test area.

[0023] Point load strength test: Point load strength index test was conducted near the rebound value test point to evaluate the internal strength of the rock mass. A calibrated portable point load tester was used, and a 50 mm diameter core sample was drilled using a handheld core drill. After the core was trimmed to a length approximately equal to its diameter, it was placed between the ball and cone ends of the tester and loaded at a uniform rate of 0.5-1.0 MPa / s until the specimen broke. The peak failure load P was recorded, and the spacing between loading points D was accurately measured. The uncorrected point load strength index Is = P / D² was then calculated. To ensure data reliability, at least three valid specimens were prepared at the same location for testing. Specimens with a deviation of more than 20% from the average value of Is were removed. The average value of Is from the valid specimens was taken as the point load strength index characterization value for that location, denoted as Is(50), in MPa.

[0024] All on-site test data, including the point load strength index Is(50), rebound value R, and environmental photos of the test points, were verified by on-site technicians via mobile terminals and then uploaded to the monitoring system data center.

[0025] Before performing the fusion analysis, the three types of parameters (f, Is, R) need to be preprocessed, and a unified evaluation benchmark needs to be established. The natural frequency is based on the initial monitoring value during the stable period; the rebound value R and the point load intensity index Is(50) need to be compared with the corresponding historical benchmark values ​​obtained in the safe area when the unstable rock mass is in a stable state (the historical benchmark value of the rebound value is denoted as R0, and the historical benchmark value of the point load intensity index is denoted as Is0). The key evaluation index is whether the verification value has changed beyond the normal fluctuation range relative to its benchmark value. In this embodiment, if the decrease in the verification value of any parameter relative to its historical benchmark value exceeds 10%, it is considered a significant abnormal signal.

[0026] The diagnostic system inputs the current natural frequency variation trend, the point load intensity index, and the rebound value into a pre-established multi-parameter collaborative diagnostic model; The multi-parameter collaborative diagnostic model outputs damage pattern recognition results for unstable rock masses based on the following logical rules: Mode 1: The natural frequency f(t) or dynamic stability coefficient K(t) shows a sustained and significant decrease. The rebound value R and point load strength index Is(50) obtained from the on-site verification remain stable, with no significant change compared to their historical benchmark values ​​R0 and Is0, indicating that the dangerous rock mass has suffered "structural surface damage". The point load strength directly reflects the internal strength of the rock material, and its stability indicates that the rock itself has not deteriorated. The rebound value characterizes the hardness of the rock mass surface, and its stability indicates that shallow weathering is not obvious. The decrease in natural frequency is directly related to the decrease in the overall stiffness of the dangerous rock mass. Combining the three, it can be seen that the root cause of the decrease in stiffness is not a material strength problem, but rather that the weak structural surfaces between or inside the dangerous rock mass and the parent rock have relaxed, opened, or undergone initial shear deformation, leading to a decrease in the structural connection stiffness.

[0027] Mode 2: The natural frequency f(t) and rebound value R decreased significantly, but the point load strength index Is(50) remained stable, indicating that the unstable rock mass underwent "surface weathering and deterioration". The stable point load strength indicates that the strength of the rock material inside the unstable rock mass did not decrease significantly. The decrease in rebound value clearly indicates that the hardness of the rock surface decreased due to weathering. The decrease in natural frequency can be attributed to the reduced contribution of surface rock stiffness degradation to the overall stiffness of the unstable rock mass. This indicates that the damage mainly originated from the surface weathering of the rock mass, while the internal materials and main structural surfaces remained relatively intact during the monitoring period.

[0028] Mode 3: The natural frequency f(t) decreases significantly, and the point load strength index Is(50) also decreases, but the rebound value R remains stable, showing no significant change compared to its historical baseline value R0, indicating that the unstable rock mass has undergone "internal material deterioration". The decrease in point load strength directly indicates that the strength of the internal materials of the unstable rock mass has decreased. The stable rebound value indicates that the weathering of the rock mass surface is not yet obvious, and the damage is mainly concentrated in the interior. This suggests that the root cause of the damage may lie in the water-rock interaction, chemical corrosion, or the development of micro-fractures within the unstable rock mass.

[0029] Mode 4: Simultaneously, the natural frequency f(t) shows a significant decrease, and the point load strength index Is(50) and rebound value R also show a synchronous downward trend, indicating that the unstable rock mass has undergone "comprehensive deterioration." The decrease in point load strength indicates a reduction in the intrinsic strength of the rock material. The decrease in rebound value indicates a reduction in the surface hardness of the rock mass. This suggests that the unstable rock mass has experienced comprehensive strength degradation and weathering from the inside to the surface, possibly due to water-rock interaction, freeze-thaw cycles, or chemical weathering.

[0030] The diagnostic process of this invention, which transforms from a single-parameter early warning mode to a multi-parameter collaborative discrimination mode, greatly enhances the accuracy and reliability of unstable rock mass stability assessment.

[0031] The diagnostic report is automatically generated by the system and must comprehensively and clearly describe the current condition of the unstable rock mass and the risks it faces. The initial section of the report should clearly indicate the relevant information about the unstable rock mass and the exact monitoring and diagnostic time. The core section details the monitoring and diagnostic results, including the trend of natural frequency changes, changes in the stability of the unstable rock mass, the point load intensity index and rebound value data obtained from verification, and the damage mode diagnostic conclusions after multi-source data fusion analysis. The report concludes with key monitoring data and on-site verification photographs.

[0032] Based on different damage patterns of unstable rock masses, the system outputs targeted remediation design solutions: Structural surface damage: The core of the treatment is to restore the connection between the unstable rock mass and the parent rock structural surface. Prestressed anchor bolts (cables) are used first for active anchoring, while pressure grouting is carried out to reinforce the damaged structural surface. Internal deterioration: The core of the treatment lies in implementing deep reinforcement and blocking the source of deterioration. The priority is to use full-length bonded anchor bolts (cables) for deep anchoring, so that they pass through the deteriorated area and are anchored to stable rock layers. It is also necessary to investigate and drain environmental factors such as groundwater that cause internal deterioration. Surface deterioration: The core of the treatment is to carry out timely surface protection and immediately take effective measures such as netting and spraying to isolate the weathering forces and prevent the damage from developing into deeper layers; Comprehensive deterioration: A comprehensive treatment plan is required. In addition to using anchoring measures to ensure overall stability, surface protection measures such as wire mesh spraying should be integrated to prevent further weathering and debris from falling off.

[0033] The conclusions drawn from this diagnosis should be fed back into the dynamic optimization process of the monitoring plan. For unstable rock masses with structural surface damage, subsequent monitoring should include enhanced monitoring of the opening and closing degree of key structural surfaces. For unstable rock masses with internal material deterioration, subsequent monitoring should include denser sampling points for load intensity during verification testing to monitor the range and extent of internal strength changes. For unstable rock masses with surface weathering and deterioration, the frequency and testing area of ​​rebound tests should be appropriately increased to assess the effectiveness of surface protection measures and the weathering trend. For unstable rock masses with complete deterioration, the monitoring frequency of the inherent frequency should be appropriately increased. Through a closed-loop monitoring system of monitoring-diagnosis-treatment-assessment, a precise control system for the entire life cycle of unstable rock masses can be formed to ensure project safety.

[0034] like Figure 2 The schematic diagram illustrating the application scenario of the integrated monitoring and early warning method for unstable rock masses combining rebound hammer and point load is shown in this embodiment two, which uses a high-risk limestone slope along a highway as an example. Obvious tensile fractures are visible at the top of the slope, and local collapses have occurred historically. To ensure highway traffic safety, the method of this invention is used to monitor this unstable rock mass.

[0035] High-precision micro-core pile vibration sensors were installed at the top and bottom of the stable bedrock of the potentially unstable rock mass, which is different from the parent rock of the unstable rock mass, to establish an automated data acquisition and remote transmission system. After seven days of continuous observation, it was determined that the unstable rock mass was in a relatively stable state, with an initial reference natural frequency f0 = 15.2 Hz.

[0036] After long-term automated monitoring and trend identification, the natural frequency continuously decreased from 15.2Hz to 14.3Hz. The data analysis module identified a sustained and significant downward trend, and the trend statistical test p-value was less than 0.05. The system automatically triggered an early warning signal.

[0037] Technicians first selected a verification test point in a safe location outside the affected area of ​​the fracture at the rear edge of the unstable rock mass to conduct rebound hammer tests. Within this 200cm×200cm test area, 16 test points were evenly arranged using an orthogonal grid method. After removing the three maximum and three minimum values, the average effective rebound value was calculated to be R=50, which remained stable compared to the historical baseline value R0=50.

[0038] Then, point load strength tests were conducted near the rebound value test points. Three 50mm diameter rock core samples were drilled using a handheld core drill and tested with a portable point load tester. The point load strength index Is(50) = 2.48MPa was calculated. Compared with the historical benchmark value Is(50) = 2.50MPa during the stability period of the slope, there was no significant change.

[0039] The system fused and analyzed the above data: the input data showed a significant decrease in natural frequency (natural frequency change value was -0.9Hz), stable point load strength index (Is(50)=Is0), and stable rebound value (R=R0). This data pattern fully conforms to the characteristics of "structural surface damage", that is, the strength and surface hardness of the rock material itself have not decreased, but the overall stiffness has decreased significantly. The diagnostic conclusion is that the root cause of the stability deterioration of the dangerous rock mass is the damage to the weak structural surface between the dangerous rock mass and the bedrock, rather than the deterioration of the rock material itself.

[0040] The system generated a "Comprehensive Monitoring and Diagnostic Report on the Dangerous Rock Mass," clearly indicating that the stability of the dangerous rock mass was deteriorating, the damage mode was structural surface damage, and the treatment recommendations focused on restoring and strengthening structural connections. It recommended the use of prestressed anchor bolts (cables) for active anchoring and pressure grouting reinforcement of the damaged structural surfaces. The report was also sent to the design unit.

[0041] The engineering design unit adopted the diagnostic conclusions and formulated a reinforcement scheme based on "full-length bonded prestressed anchor cables + structural surface pressure grouting". At the same time, the subsequent monitoring scheme was optimized. In addition to the original vibration monitoring, special monitoring of the opening and closing degree of the identified key structural surfaces was added, realizing closed-loop management of the entire process from accurate diagnosis to effective treatment of the dangerous rock mass.

[0042] like Figure 3 As shown, this embodiment three provides a comprehensive monitoring and early warning system for unstable rock masses that combines a rebound hammer and point load, including: The multi-parameter automatic monitoring data acquisition module is used to deploy sensing and data acquisition equipment on the unstable rock mass. Specifically, it includes vibration sensors installed on or inside the unstable rock mass to collect vibration signals of the unstable rock mass under environmental excitation in real time. The natural frequency analysis and early warning module is used to receive and process the data uploaded by the multi-parameter automatic monitoring data acquisition module. By performing spectrum analysis on the obtained vibration signal, it calculates the natural frequency of the unstable rock mass. By performing trend analysis on the natural frequency, it identifies whether the natural frequency has decreased significantly compared to the corresponding initial reference value, and generates and issues an early warning signal when the natural frequency decreases significantly compared to the corresponding initial reference value. The on-site verification test module includes a point load test unit and a rebound value test unit for on-site verification. The point load testing unit is used to perform on-site testing of the point load strength index at preset safe locations of unstable rock masses during the verification process, and to transmit the data back. The rebound value testing unit is used to perform on-site testing of the surface rebound value at a preset safe location of the dangerous rock mass during the verification process, and to transmit the data back. The on-site verification test module is used to perform on-site tests of point load strength index and surface rebound value at preset safe locations of dangerous rock masses after the point load test unit and rebound value test unit receive the warning signal from the natural frequency analysis and early warning module, and then transmit the data back. The multi-source data fusion diagnostic module is used to integrate the natural frequency change trend generated by the natural frequency analysis and early warning module, as well as the point load strength index and rebound value obtained by the point load test unit and rebound value test unit on site, and perform collaborative analysis and diagnosis; and judge and classify the damage mode of the unstable rock mass through the diagnostic logic rules in the pre-established multi-parameter collaborative diagnostic model. The comprehensive report generation and feedback module is used to generate a comprehensive monitoring and diagnostic report containing the damage pattern of the dangerous rock mass and targeted treatment suggestions based on the diagnostic conclusions output by the multi-source data fusion diagnostic module, and to feed the comprehensive monitoring and diagnostic report back to the engineering design and monitoring management department to facilitate the formulation of engineering treatment plans and subsequent monitoring plans.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0044] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A comprehensive monitoring and early warning method for unstable rock masses combining rebound hammers and point loads, characterized in that, Includes the following steps: Acquire real-time monitoring data of the unstable rock mass, including the current natural frequency obtained through long-term monitoring and analysis using vibration sensors; In response to a significant decrease in the current inherent frequency compared to the corresponding initial reference value, the on-site verification process is triggered to obtain the point load intensity index and rebound value of the unstable rock mass during the same verification period; The current natural frequency variation trend, the point load intensity index, and the rebound value are input into a pre-established multi-parameter collaborative diagnostic model; The multi-parameter collaborative diagnostic model outputs damage pattern recognition results for unstable rock masses based on the following logical rules: If only the natural frequency decreases, while the point load strength index and rebound value remain stable, the damage mode is identified as structural surface damage. If the natural frequency and rebound value decrease synchronously, while the point load strength index remains stable, the damage mode is identified as surface weathering and deterioration. If the natural frequency and the point load strength index decrease synchronously, while the rebound value remains stable, the damage mode is identified as internal material degradation. If the natural frequency, point load strength index, and rebound value all decrease simultaneously, the damage mode is identified as overall degradation.

2. The comprehensive monitoring and early warning method for unstable rock masses combining rebound hammer and point load as described in claim 1, characterized in that, The specific criteria for determining whether the current natural frequency has significantly decreased compared to the corresponding initial reference value are as follows: The dynamic stability coefficient is calculated based on the current natural frequency and the initial reference natural frequency. The calculation formulas are as follows: Where K(t) represents the current dynamic stability coefficient of the unstable rock mass; f(t) represents the current natural frequency of the unstable rock mass; and f0 represents the initial reference value of the natural frequency of the unstable rock mass. When the cumulative decrease of K(t) exceeds the preset value and the trend of K(t) shows a negative slope in statistics, it is determined that the current natural frequency has decreased significantly compared with its initial baseline value.

3. The comprehensive monitoring and early warning method for unstable rock masses combining rebound hammer and point load as described in claim 1, characterized in that, In the on-site verification process, the point load strength index of the unstable rock mass during the same verification period is obtained by a point load tester, and the rebound value of the unstable rock mass during the same verification period is obtained by a rebound hammer. The criteria for judging whether the point load intensity index is in a stable or declining state are as follows: compare the measured value of the point load intensity index obtained from the on-site verification with the historical benchmark value of the point load intensity index obtained during the stabilization period of the unstable rock mass. If the decline exceeds the first threshold, the point load intensity index is judged to be in a declining state; otherwise, the point load intensity index is judged to be in a stable state. The criteria for judging whether the rebound value is in a stable or declining state are as follows: compare the measured rebound value obtained from the on-site verification with the historical benchmark value of the rebound value obtained during the stable period of the unstable rock mass. If the decline exceeds the second threshold, the rebound value is judged to be in a declining state; otherwise, the rebound value is judged to be in a stable state.

4. The comprehensive monitoring and early warning method for unstable rock masses combining rebound hammer and point load as described in claim 3, characterized in that, During the on-site verification process, when obtaining the point load strength index and rebound value of the unstable rock mass in the same verification period, the location of the unstable rock mass for verification testing using a point load tester and a rebound tester must meet the following constraints: it must be located outside the influence zone of the rear edge crack of the unstable rock mass, the rock mass must be intact without obvious open cracks, and the rock surface must be relatively flat to facilitate safe operation.

5. The comprehensive monitoring and early warning method for unstable rock masses combining rebound hammer and point load as described in claim 1, characterized in that, The method also includes generating a comprehensive monitoring and diagnostic report containing the damage pattern of the unstable rock mass and targeted treatment suggestions based on the damage pattern identification results of the unstable rock mass. Targeted treatment recommendations for unstable rock mass damage patterns include: For structural surface damage, it is recommended to use prestressed anchor bolts (cables) for anchoring and / or grouting reinforcement of the structural surface; For internal material deterioration, it is recommended to use full-length bonded anchor bolts (cables) for deep anchoring; For surface weathering and deterioration, it is recommended to use wire mesh spraying for surface protection; For overall degradation, it is recommended to adopt a comprehensive treatment approach that combines anchoring and surface protection.

6. A comprehensive monitoring and early warning system for unstable rock masses combining rebound hammers and point loads, employing the comprehensive monitoring and early warning method for unstable rock masses combining rebound hammers and point loads as described in any one of claims 1 to 5, characterized in that... include: The multi-parameter automatic monitoring data acquisition module is used to deploy sensing and data acquisition equipment on the unstable rock mass. Specifically, it includes vibration sensors installed on or inside the unstable rock mass to collect vibration signals of the unstable rock mass under environmental excitation in real time. The natural frequency analysis and early warning module is used to receive and process the data uploaded by the multi-parameter automatic monitoring data acquisition module. By performing spectrum analysis on the obtained vibration signal, it calculates the natural frequency of the unstable rock mass. By performing trend analysis on the natural frequency, it identifies whether the natural frequency has decreased significantly compared to the corresponding initial reference value, and generates and issues an early warning signal when the natural frequency decreases significantly compared to the corresponding initial reference value. The on-site verification test module includes a point load test unit and a rebound value test unit for on-site verification. After receiving the warning signal from the natural frequency analysis and early warning module, it performs on-site tests of the point load strength index and surface rebound value at the preset safe location of the unstable rock mass and transmits the data back. The multi-source data fusion diagnostic module is used to integrate the natural frequency change trend generated by the natural frequency analysis and early warning module, as well as the point load strength index and rebound value obtained by the point load test unit and rebound value test unit on site, and perform collaborative analysis and diagnosis; and judge and classify the damage mode of the unstable rock mass through the diagnostic logic rules in the pre-established multi-parameter collaborative diagnostic model. The comprehensive report generation and feedback module is used to generate a comprehensive monitoring and diagnostic report containing the damage pattern of the dangerous rock mass and targeted treatment suggestions based on the diagnostic conclusions output by the multi-source data fusion diagnostic module, and to feed the comprehensive monitoring and diagnostic report back to the engineering design and monitoring management department to facilitate the formulation of engineering treatment plans and subsequent monitoring plans.

7. The integrated monitoring and early warning system for unstable rock masses combining a rebound hammer and point load as described in claim 6, characterized in that, The point load testing unit is used to perform on-site testing of the point load strength index at preset safe locations of unstable rock masses during the verification process, and to transmit the data back. The rebound value testing unit is used to perform on-site testing of the surface rebound value at a preset safe location of the dangerous rock mass during the verification process, and to transmit the data back.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the integrated monitoring and early warning method for unstable rock masses combining rebound hammers and point loads as described in any one of claims 1 to 5.

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