Evaluation and early warning method for structural plane deterioration of dangerous rock in reservoir area under water level and vibration coupling

Abstract

The application discloses a reservoir area dangerous rock structure surface deterioration evaluation and early warning method based on water level vibration coupling, and belongs to the technical field of reservoir bank geological disaster prevention and control. Dangerous rock mass lithology, structure surface geometric characteristics, water level fluctuation, vibration disturbance and multi-source response monitoring parameters are collected, and water level fluctuation damage factors, vibration damage factors, structure surface control factors and multi-source response factors are calculated respectively. Four types of factors are weighted and fused to construct a comprehensive deterioration index. Finally, the stability grade is determined in combination with the dynamic correction of the grading early warning threshold, and the early warning result is output. The application integrates water level fluctuation and vibration coupling damage, structure surface geometric control effect and multi-source monitoring information into a unified evaluation system, can quantitatively characterize the structure surface deterioration evolution process, realizes dynamic threshold early warning, has the characteristics of comprehensive evaluation, strong adaptability and accurate early warning, and can provide reliable technical support for reservoir area dangerous rock stability evaluation, monitoring prevention and control and emergency disposal.

Description

Technical Field

[0001] This invention relates to the field of reservoir bank geological disaster prevention and control technology, specifically to a method for evaluating and warning of the deterioration of dangerous rock structure surfaces in reservoir areas based on water level vibration coupling. Background Technology

[0002] The stability of unstable rock formations in reservoir areas is jointly controlled by reservoir water level fluctuations, seismic disturbances, and the geometric conditions of structural surfaces, making it a core issue in reservoir bank geological disaster prevention and control. During long-term reservoir operation, the periodic rise and fall of water levels causes repeated soaking, softening, and shrinkage of the rock mass controlling the structural surfaces, leading to weakened particle cementation, the initiation and expansion of microcracks, and continuous deterioration of mechanical properties such as compressive strength and elastic modulus. Simultaneously, the vibrations from ship waves, traffic loads, micro-seismic events, and engineering blasting apply cyclic dynamic loads to the already deteriorated structural surfaces, further exacerbating damage accumulation and crack penetration, significantly increasing the risk of unstable rock formations and collapse. Such disasters are characterized by their suddenness and destructive power, directly threatening the safety of navigation channels in the reservoir area, coastal engineering facilities, and the lives and property of the people. Therefore, developing accurate and reliable methods for assessing structural surface deterioration and providing early warning of instability is of significant engineering value and theoretical importance for the long-term prevention and control of geological disasters in reservoir areas.

[0003] Current academic research has extensively explored the mechanisms of rock mass degradation under the influence of water level fluctuations and seismic activity, laying a theoretical foundation for the evaluation of unstable rock formations. The study "Research on Macro- and Micro-scale Composite Damage Model of Limestone under Coupling of Wet and Dry Loads" reveals the degradation patterns of limestone strength and wave velocity under the coupling of wet and dry cycles and dynamic loads through a split Hopkinson bar test, and constructs a composite damage constitutive model to simulate the coupled damage evolution process. The study "Stability Analysis of Red Mudstone Slopes in Reservoir Areas under Wet and Dry Cycles and Seismic Coupling" confirms that wet and dry cycle degradation is the physical basis for slope instability, with seismic loads as the direct driving force, and the coupling effect significantly reducing slope stability. The study "Evolution Mechanism of Triaxial Compression Damage in Jointed Sandstone under Wet and Dry Cycles" elucidates the deteriorating nature of wet and dry cycles, which reduces the rock's energy storage capacity and exacerbates energy dissipation. The study "Stability Analysis and Prevention Engineering Design of the Dangerous Rock Mass at Jianchuandong in the Wuxia Gorge of the Three Gorges Reservoir Area" verifies through field tests that the rise and fall of reservoir water causes a 20%–30% reduction in the strength of the dangerous rock base, making it prone to overturning or sliding failure. The above findings clarify the coupling degradation mechanism between water level rise and fall and vibration, but they mostly focus on the analysis of single mechanical parameters or energy indicators, and do not incorporate water level rise and fall paths, vibration accumulation, structural surface inclination and roughness, and multi-source monitoring response into a unified evaluation framework, making it difficult to achieve quantitative characterization and dynamic early warning of the degree of degradation.

[0004] Existing Chinese patents have explored numerous methods for monitoring and early warning of unstable rock formations, but none have resolved the core issues of characterizing the coupling of water level rise and fall with vibration damage on unstable rock structures in reservoirs and establishing dynamic threshold early warning systems. Patent CN113686274A proposes a method for measuring water depth in unstable rock fissures and providing early warning of collapse. It uses ultrasonic pulse flat-surface measurement to monitor fissure depth and relies on hydrological and deformation data for early warning, but it does not consider the coupling degradation caused by water level rise and fall cycles and vibration, thus failing to quantify the degree of structural strength degradation. Patent CN113010835A discloses a method and system for early warning of unstable rock collapse based on fracture mechanics. It calculates fissure opening displacement based on fracture mechanics, focusing only on the geometric expansion of fissures and failing to integrate water-rock degradation and dynamic load damage. Its early warning threshold is fixed and limited. Poor adaptability; Publication No. CN116448883A discloses a method, system, equipment, and terminal for monitoring and early warning of dangerous rock masses on steep cliffs and high positions. It monitors the expansion of cracks in dangerous rocks through acoustic emission, focusing on the identification of fracture signals. It does not establish a correlation mechanism between water level rise and fall, vibration, and structural surface deterioration, and lacks a comprehensive deterioration index and dynamic threshold system. Publication No. CN113326756A discloses a method for identifying potential landslide hazards on reservoir banks based on rock mass deterioration characteristics. It uses remote sensing and three-dimensional modeling technology, focusing on hazard identification rather than quantitative evaluation and real-time early warning of structural surface strength deterioration. These technologies either rely on a single monitoring indicator, have fixed thresholds, or fail to achieve coupled damage quantification, and cannot meet the needs of accurate evaluation and early warning of dangerous rock surface structures in reservoir areas.

[0005] Existing academic research has revealed the mechanism of coupled degradation but lacks engineering evaluation methods. Existing patented technologies have achieved local monitoring and early warning but have not solved the problems of damage chain coupling and dynamic threshold. They are all difficult to simultaneously cover the simulation of the real path of water level rise and fall in the reservoir area, the characterization of the control effect of inclined structural surfaces, the quantification of continuous coupled damage of water level rise and fall, vibration and compression, the evaluation of multi-source parameter fusion, and the need for dynamic threshold correction. Summary of the Invention

[0006] To address the aforementioned technical issues, this application discloses a method for evaluating and providing early warning of the deterioration of unstable rock structures in reservoir areas based on water level-vibration coupling, including the following:

[0007] S1. Collect basic parameters of the unstable rock structure in the target reservoir area. The basic parameters include lithological parameters of the unstable rock mass, geometric parameters of the structure, time series data of water level rise and fall in the reservoir area, physical parameters of vibration disturbance, and multi-source response monitoring data of the structure.

[0008] S2. Based on the reservoir water level rise and fall time series data, extract the dry-wet cycle number, soaking time, water loss time, and water level rise and fall amplitude characteristic parameters, and calculate the water level rise and fall damage factor.

[0009] S3. Based on the physical parameters of vibration disturbance, extract the characteristic parameters of vibration frequency, acceleration amplitude, and vibration duration, and calculate the vibration damage factor.

[0010] S4. Based on the geometric parameters of the structural surface, extract the characteristic parameters of the structural surface tilt angle, structural surface continuity rate, and structural surface roughness coefficient, and calculate the structural surface control factor.

[0011] S5: Based on the multi-source response monitoring data of the structural surface, extract wave velocity parameters, acoustic emission parameters, crack image parameters, displacement parameters, and energy dissipation parameters, and calculate the multi-source response factor;

[0012] S6. The water level rise and fall damage factor, vibration damage factor, structural surface control factor and multi-source response factor are weighted and fused to construct the comprehensive deterioration index of dangerous rock structure in the reservoir area.

[0013] S7. Compare the comprehensive deterioration index with the dynamically corrected warning threshold, classify the stability level of the dangerous rock structure according to the comparison results, and output the warning result of the corresponding level.

[0014] Preferably, the water level rise and fall damage factor in S2 The damage evolution is determined using an exponential damage evolution formula, which is as follows:

[0015]

[0016] in, , , , All parameters were determined through fitting during indoor coupling degradation experiments; The total number of wet and dry cycles experienced by the structural rock mass due to the periodic rise and fall of the reservoir water level; The duration of water immersion in the structural rock mass during a single water level rise or fall; This is the preset baseline soaking time; This represents the actual rise or fall of the water level during a single rise or fall process. This is the preset baseline water level rise and fall range.

[0017] Preferably, the vibration damage factor in S3 The damage accumulation formula is used to determine the extent of the damage, which is:

[0018]

[0019] in, , , , All parameters were determined through fitting of indoor vibration loading tests; This represents the actual amplitude of the vibrational acceleration acting on the rock mass at the structural surface. The preset reference vibration acceleration amplitude; This refers to the actual frequency of vibration acting on the rock mass at the structural surface; The preset reference vibration frequency; This refers to the actual duration of the vibration load acting on the rock mass of the structural surface. This is the preset reference vibration duration.

[0020] Preferably, the structural surface control factor in S4 It is determined by the linear weighted combination formula, which is:

[0021]

[0022] in, , , All of these are dimensionless weighting coefficients preset based on engineering geological conditions; The angle between the main structural plane controlling the unstable rock and the horizontal plane; It is the ratio of the length of the structural surface through to the total length of the structural surface, representing the degree of structural surface continuity; The actual surface roughness coefficient of the structure is obtained through on-site measurement or indoor testing; This is the preset reference roughness coefficient.

[0023] Preferably, the multi-source response factor in S5 It is composed of five categories of indicators, namely wave velocity damage variable, acoustic emission activity index, crack area ratio index, displacement mutation rate index, and dissipation energy ratio index, which are linearly weighted and summed to comprehensively reflect the changes in the physical and mechanical response of the structural surface during the deterioration process.

[0024] Preferably, the wave velocity damage variable The relative change of P-wave velocity is determined by the formula, which is:

[0025]

[0026] in, The current longitudinal wave velocity of the rock mass at the structural plane is obtained through detection during the deterioration process. The initial longitudinal wave velocity of the rock mass at the structural surface before it has experienced water level fluctuations and vibration damage. Used to characterize the degree of structural damage caused by wave velocity attenuation.

[0027] Preferably, the crack area ratio index The crack area ratio is determined using the following formula:

[0028]

[0029] in, The total area of ​​all cracks extracted from the surface of a rock sample or the on-site monitoring area of ​​a dangerous rock using image recognition technology; This refers to the total surface area of ​​the rock sample used for testing or the total area of ​​the on-site monitoring area for dangerous rocks. Used to characterize the extent of crack propagation on the surface of a structural plane.

[0030] Preferably, the comprehensive degradation index in S6 The formula is determined using a four-dimensional factor linear weighting formula, as follows:

[0031]

[0032] in, , , , All are normalized weighting coefficients preset based on the geological conditions and engineering requirements of the reservoir area, and satisfy the following conditions: , The value ranges from 0 to 1, with a larger value indicating a higher degree of structural deterioration.

[0033] Preferably, the dynamic early warning threshold in S7 includes a stable threshold. Mild degradation threshold moderate degradation threshold Severe degradation threshold Approaching the instability threshold The threshold is adjusted in real time based on the lithological parameters of the dangerous rock mass, the dip angle parameters of the structural surface, and the number of historical water level rise and fall cycles, to adapt to the deterioration characteristics of different reservoir areas and different dangerous rock structural surfaces.

[0034] Preferably, the stability level in S7 is based on the comprehensive degradation index. The relative relationship with the dynamic early warning threshold is as follows:

[0035] when At that time, the unstable rock structure was determined to be in a stable state;

[0036] when At that time, the unstable rock structure was determined to be in a state of slight deterioration;

[0037] when At that time, the unstable rock structure was determined to be in a state of moderate deterioration;

[0038] when At that time, the unstable rock structure was determined to be in a state of severe deterioration;

[0039] when At that time, the unstable rock structure was determined to be in a near-instability state.

[0040] Compared with the prior art, the technical solution of this application has the following technical effects:

[0041] This invention can fully construct the damage evolution chain of dangerous rock structures in reservoirs under the coupled action of water level rise and fall and vibration. It integrates water level rise and fall damage, vibration cumulative damage, geometric control effect of structural surfaces, and multi-source monitoring response into the evaluation system, realizing the quantitative characterization of the entire process of damage from generation to development, making the identification of structural surface deterioration state more complete and in line with actual engineering conditions.

[0042] This invention obtains a comprehensive degradation index by fusing multi-source physical monitoring information. It combines multiple indicators such as wave velocity change, acoustic emission characteristics, crack propagation, displacement response, and energy dissipation to effectively improve the comprehensiveness and reliability of the assessment of structural surface degradation, ensuring that the assessment results are not affected by fluctuations in a single indicator and stably reflect the true degradation level.

[0043] This invention can dynamically adjust the early warning threshold based on lithological conditions, structural surface geometric parameters, and historical water level rise and fall processes, making the early warning standard adaptable to dangerous rock masses in different reservoir areas, with different lithologies and structural surface conditions. This improves the applicability and versatility of the method in complex engineering environments and can be directly used for both on-site monitoring and indoor testing.

[0044] This invention uses a comprehensive deterioration index to accurately classify and output the stability level of unstable rock structures, providing a clear quantitative basis for daily inspection, monitoring, engineering protection, and emergency response of unstable rocks in reservoir areas. It enables real-time determination of the deterioration state of unstable rock structures and timely early warning of instability risks, ensuring the safety of reservoir projects and the environment.

[0045] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0046] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0048] Based on the description of the figures and their corresponding technical content in the document, the titles of the figures are as follows:

[0049] Figure 1 Flowchart of the overall evaluation method for the deterioration of dangerous rock structures in reservoir areas based on the damage chain of water level rise and fall vibration;

[0050] Figure 2 A schematic diagram of the damage chain evolution of dangerous rock structures in the reservoir area under the coupled effect of water level rise and fall vibration disturbance;

[0051] Figure 3 A schematic diagram of the standardized fusion processing flow of multi-source monitoring data on dangerous rock structures in the reservoir area;

[0052] Figure 4 A diagram showing the correlation between the comprehensive deterioration index of unstable rock structures in the reservoir area and the dynamic early warning of their stability levels.

[0053] Figure 5 A schematic diagram of the on-site layout and data transmission topology of the multi-source synchronous monitoring equipment for dangerous rocks on the reservoir bank. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0055] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0056] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0057] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0058] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0059] It should also 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.

[0060] Example 1 describes a method for evaluating and warning of the deterioration of dangerous rock structures in reservoirs based on water level vibration coupling, including the following steps:

[0061] S1. Collect basic parameters of the unstable rock structure in the target reservoir area. The basic parameters include lithological parameters of the unstable rock mass, geometric parameters of the structure, time series data of water level rise and fall in the reservoir area, physical parameters of vibration disturbance, and multi-source response monitoring data of the structure.

[0062] S2. Based on the reservoir water level rise and fall time series data, extract the dry-wet cycle number, soaking time, water loss time, and water level rise and fall amplitude characteristic parameters, and calculate the water level rise and fall damage factor.

[0063] S3. Based on the physical parameters of vibration disturbance, extract the characteristic parameters of vibration frequency, acceleration amplitude, and vibration duration, and calculate the vibration damage factor.

[0064] S4. Based on the geometric parameters of the structural surface, extract the characteristic parameters of the structural surface tilt angle, structural surface continuity rate, and structural surface roughness coefficient, and calculate the structural surface control factor.

[0065] S5. Based on the multi-source response monitoring data of the structural surface, extract wave velocity parameters, acoustic emission parameters, crack image parameters, displacement parameters, and energy dissipation parameters, and calculate the multi-source response factor.

[0066] S6. The water level rise and fall damage factor, vibration damage factor, structural surface control factor and multi-source response factor are weighted and fused to construct the comprehensive deterioration index of dangerous rock structure in the reservoir area.

[0067] S7. Compare the comprehensive deterioration index with the dynamically corrected warning threshold, classify the stability level of the dangerous rock structure according to the comparison results, and output the warning result of the corresponding level.

[0068] Furthermore, the basic parameters of the unstable rock structure in the target reservoir area were collected in all dimensions. The collected data covered lithological parameters of the unstable rock mass, geometric parameters of the main controlling structural surface, time-series data of the entire process of water level rise and fall in the reservoir area, physical parameters of external vibration disturbance, and monitoring data of multi-physics response generated by the structural surface during the deterioration process. These data together constitute the basic data source for all subsequent quantitative calculations, factor solutions, and evaluation analyses. As shown in Figure 1, the overall execution flow of this method starts with the collection of basic parameters, and then proceeds to four independent and continuous quantitative solution stages: calculation of water level rise and fall damage factors, calculation of vibration damage factors, calculation of structural surface control factors, and calculation of multi-source response factors. After completing the standardized calculation of the four types of core damage and control factors, the four types of factors are weighted and fused to obtain a comprehensive deterioration index that can uniquely characterize the overall deterioration degree of the structural surface. Finally, the comprehensive deterioration index is compared with the warning threshold after dynamic correction based on lithology, structural surface conditions, and historical water level cycles to complete the classification of structural surface stability levels and output the corresponding warning results and engineering treatment suggestions. The entire process forms a complete technical closed loop, which is completely consistent with the actual deterioration physical mechanism of dangerous rock structures in the reservoir area under the combined influence of water and rock action and dynamic loads, ensuring that the evaluation results are true and reliable and the early warning output is timely and effective.

[0069] After the basic parameters were collected, a water level rise and fall damage factor was calculated based on the actual operation process of water level rise and fall in the reservoir area. This factor is used to quantitatively characterize a series of water-rock interaction damage effects caused by the periodic rise and fall of water level, such as softening of structural rock mass due to immersion, shrinkage due to water loss, weakening of mineral particle cementation, and initiation and propagation of internal microcracks. The exponential nonlinear damage evolution formula was used for calculation, and the formula is as follows:

[0070]

[0071] In the formula, The value is the damage factor caused by water level rise and fall, and its value is stable between 0 and 1. The closer the value is to 1, the more severe the damage to the structural surface caused by water level. , , , The dimensionless calculation parameters obtained through indoor coupled degradation tests are as follows: For the widely distributed marl, sandstone, and argillaceous dolomite rocks in the reservoir area, the commonly used engineering values ​​are... , , , ; The total number of dry and wet cycles formed by the periodic rise and fall of water level in the reservoir area is 8 to 15 complete cycles per year in a typical area of ​​the Three Gorges Reservoir drawdown zone. This refers to the duration during which the rock mass of the structural plane is continuously soaked by reservoir water during a single water level rise or fall. The duration of high water levels in the reservoir area is typically 30 to 90 days. To ensure a uniform standard soaking time, a fixed value of 24 hours was set. The actual amplitude of a single water level rise or fall is 20 to 30 meters, representing the mainstream operating water level fluctuation in the Three Gorges Reservoir area. To ensure a uniform baseline, the water level fluctuation range is fixed at 1 meter. This formula accurately reflects the nonlinear cumulative effect of the number of wet-dry cycles, soaking duration, and water level fluctuation range on structural surface damage. As the number of cycles increases, the soaking time extends, and the water level fluctuation range gradually increases, the density and propagation length of microcracks within the structural surface continuously rise, and the water level fluctuation damage factor gradually approaches 1, indicating that the damage to the structural surface under the sole effect of water level fluctuation gradually reaches saturation.

[0072] After the water level rise and fall damage factor is calculated, the vibration damage factor is further solved based on the vibration disturbance physical parameters obtained from on-site monitoring. This factor is used to quantitatively describe the dynamic cumulative damage caused by vibration load on the structural surface that has already undergone initial softening damage, including effects such as accelerated microcrack propagation, crack penetration, reduced interlocking strength of structural surfaces, and attenuation of shear resistance. The exponential dynamic cumulative damage formula is also used for calculation, and the formula is as follows:

[0073]

[0074] In the formula, The value of is the vibration damage factor, which is stable between 0 and 1. The larger the value, the more significant the dynamic cumulative damage to the structural surface caused by vibration. , , , The dimensionless calculation parameters obtained by fitting through indoor vibration loading tests are commonly used in engineering. , , , ; The actual amplitude of the vibration acceleration acting on the rock mass of the structural plane is 0.05g to 0.3g, which is the vibration amplitude caused by ship waves in the reservoir area, traffic loads along the coast, engineering blasting, etc. To ensure a uniformly set benchmark vibration acceleration amplitude, a fixed value of 0.1g was adopted. The actual vibration frequency is 5Hz to 50Hz, which is typical for the reservoir area. To ensure a uniform reference vibration frequency, a fixed value of 10Hz was adopted. The duration of a single vibration load action is typically 10 to 600 seconds, and the duration of common disturbances in reservoir areas is generally between 10 and 600 seconds. To ensure a uniform baseline vibration duration, a fixed value of 10 seconds was used. This formula fully reflects the amplification effect of vibration acceleration amplitude, vibration frequency, and vibration duration on the dynamic damage of the structural surface. The higher the vibration intensity and the longer the duration, the faster the damage inside the structural surface expands and penetrates. This forms a strong coupling and superposition relationship with the initial damage caused by water level rise and fall, jointly promoting the continuous decay of the mechanical strength of the structural surface and the continuous increase in the risk of instability.

[0075] like Figure 2 As shown, in the water level rise and fall module, the unstable rock mass 1 is a blocky rock mass on the upper part of the reservoir bank slope, with an intact overall structure. A main control structural surface 4 is developed between the bottom and the lower bedrock, which is the core control surface for the stability of the unstable rock mass. The reservoir water level rise and fall 2 creates a periodic wet-dry cycle environment, with the water level fluctuating repeatedly between the high water level Hmax and the low water level Hmin, with a water level variation ΔH = Hmax - Hmin. When the water level rises, the main control structural surface 4 is submerged by the reservoir water. The cementing material of the rock mass softens and dissolves under the action of water and rock, increasing pore water pressure and generating initial micro-cracks inside the structural surface. When the water level falls, the structural surface is exposed and loses water, causing the rock mass to shrink and crack, further expanding the micro-cracks.

[0076] In the vibration disturbance module, vibration disturbance 3 (such as ship waves, traffic loads, and micro-vibrations) continuously acts on the unstable rock mass 1, and the vibration energy is transmitted through the rock mass medium to the main control structural surface 4, which has already suffered initial damage. Under cyclic dynamic loading, a stress concentration zone 5 is formed around the main control structural surface 4, and the initial micro-cracks are repeatedly squeezed and expanded, forming structural surface damage propagation 6 that extends along the structural surface. The vibration frequency, acceleration amplitude, and duration directly affect the damage propagation rate.

[0077] In the structural surface damage response module, the coupled damage from water level rise and fall and vibration continues to accumulate. Damage extension 6 extends along the main controlling structural surface 4, forming a continuous damage zone, and the overall mechanical strength of the structural surface decreases significantly. When the extent of damage extension 6 reaches more than 60% of the total length of the main controlling structural surface 4, the connection between the unstable rock mass 1 and the underlying bedrock is broken, stability drops sharply, the safety factor falls below 1.0, and it enters a near-instability state. Damage development at this stage is controlled by the geometric conditions of the structural surface itself; the dip angle, penetration rate, and roughness coefficient jointly determine the ease of damage penetration. Structural surfaces with high dip angles, high penetration rates, and low roughness deteriorate faster.

[0078] The entire damage chain follows a progressive pattern of pre-damage from water level rise and fall, expansion from vibration disturbance, and failure through structural surfaces. Water level rise and fall 2 provides the initial water-rock damage conditions, vibration disturbance 3 accelerates damage expansion, and the main control structural surface 4 controls the damage path and critical instability state. The coupling effect of the three ultimately leads to the instability of the unstable rock mass 1.

[0079] After calculating the two types of environmental damage factors, the structural surface control factor is further calculated. This factor is used to quantitatively characterize the dominant control effect of the geometric conditions of the main controlling structural surface on the degradation propagation path, development rate, failure mode, and critical instability conditions. The three core geometric parameters of the structural surface—tilt angle, continuity, and roughness coefficient—are incorporated into a unified calculation framework and solved using a linear weighted combination formula, which is as follows:

[0080]

[0081] In the formula, The structural surface control factor has a stable value range between 0 and 1. The larger the value, the more favorable the geometric conditions of the structural surface are for damage propagation and deterioration. , , To satisfy the normalization constraint that the sum of the three factors must be 1, based on the dimensionless weighting coefficients preset according to the on-site engineering geological conditions, the commonly used values ​​in engineering are: , , ; The dip angle is the angle between the main structural plane controlling the unstable rock mass and the horizontal plane. In the reservoir area, the common dip angle of the main structural plane controlling the unstable rock mass ranges from 30° to 75°. The maximum value of 1 is reached at an inclination angle of 45°, and the corresponding structural surface is most prone to shear slip and deterioration propagation. The structural surface penetration rate is the ratio of the penetration length of the structural surface to the total length, and its value ranges from 0 to 1. The value is 1 for a fully penetrated structural surface. The value is the actual roughness coefficient of the structural surface. For hard rock structural surfaces, the value is 6 to 12, and for soft rock structural surfaces, the value is 2 to 8. The baseline roughness coefficient is set to a fixed value of 10. This formula completely transforms the geometric characteristics of the structural surface into a quantitatively calculable control index. Structural surfaces with high inclination angles, high penetration rates, and low roughness have higher control factor values, resulting in faster deterioration rates and higher instability risks. This truly reflects the key constraint role of the structural surface's own conditions in the entire damage evolution process.

[0082] Subsequently, a multi-source response factor is calculated based on multi-source synchronous monitoring data. This factor integrates five types of physical response characteristics that occur throughout the entire process of structural surface deterioration: mechanical parameter decay, internal fracture signal, surface crack propagation, abrupt macroscopic deformation changes, and energy dissipation changes. It fuses multi-dimensional, multi-physics field monitoring information into a single quantitative index through a linear weighted summation method. The formula is:

[0083]

[0084] In the formula, It is a multi-source response factor, with a stable numerical range between 0 and 1; to These are dimensionless weighting coefficients that satisfy the normalization constraint that the sum of the five factors equals 1. Commonly used values ​​are... , , , , ; For wave velocity damage variable, As an indicator of acoustic emission activity, This is an index representing the crack area ratio. The displacement mutation rate is an indicator. This represents the proportion of dissipated energy. The wave velocity damage variable is calculated using the formula for the relative change of P-wave velocity:

[0085]

[0086] In the formula, The initial P-wave velocity is taken as 3000 m / s to 4500 m / s for intact, hard rock without any damage to the structural rock surface. The current longitudinal wave velocity represents the velocity after structural surface deterioration, which decreases continuously with increasing damage severity. The crack area ratio is calculated as the ratio of the total crack area to the total monitored surface area.

[0087]

[0088] In the formula, This represents the total area of ​​all cracks on the surface of the structural plane extracted using image recognition technology, expressed in square centimeters. The total area of ​​the rock sample test or the total area of ​​the field monitoring area is expressed in square centimeters.

[0089] like Figure 3The diagram shows the multi-source monitoring information fusion process, which fully illustrates the construction process and data processing logic of the multi-source response factor. The left side of the diagram represents the input layer, containing five core monitoring indicators: wave velocity damage variable, acoustic emission activity, crack area ratio, displacement mutation rate, and dissipated energy ratio. These correspond to overall damage within the structural surface, micro-fracture activity, surface crack scale, macroscopic slip deformation, and energy evolution characteristics, respectively. The middle section represents the processing layer, which sequentially includes four core steps: data normalization, dimensionless transformation, dynamic weight allocation, and linear weighted summation. By eliminating dimensional differences and numerical magnitude gaps between different physical quantities, the five indicators have a basis for direct comparison and synergistic fusion. An adaptive weight allocation method ensures that the contribution of each indicator matches the actual degree of degradation. The right side of the diagram represents the output layer, which outputs the fused multi-source response factor. This factor comprehensively, stably, and accurately reflects the degradation state of the structural surface, avoiding the bias, volatility, and misjudgment risks associated with single-indicator evaluation, and significantly improving the reliability and stability of the overall evaluation results.

[0090] After completing the calculations of all four core factors—water level rise and fall damage factor, vibration damage factor, structural surface control factor, and multi-source response factor—the four factors are weighted and fused to construct a comprehensive deterioration index. This index is the only quantitative indicator that can comprehensively reflect the overall deterioration degree of the unstable rock structure. It is calculated using a four-dimensional linear weighted model, and the formula is as follows:

[0091]

[0092] In the formula, The comprehensive degradation index has a stable value range of 0 to 1. , , , To normalize the dimensionless weighting coefficients and satisfy the constraint that the sum of the four factors is 1, the values ​​can be flexibly adjusted according to the geological conditions, lithological characteristics, and engineering requirements of the reservoir area. Commonly used values ​​in engineering are... , , , The comprehensive deterioration index integrates four core information categories—environmental water-rock interaction, dynamic disturbance damage, structural geometric control, and multi-physics response—into a unified evaluation standard. The index value is completely positively correlated with the degree of structural surface deterioration, and can intuitively, continuously, and stably reflect the entire process of structural surface changes from stable state, mild deterioration, moderate deterioration, severe deterioration to near instability.

[0093] Finally, the comprehensive deterioration index is compared with the dynamically adjusted warning threshold to complete the stability level classification of the unstable rock structure and output the corresponding warning results. As shown in Figure 4, the quantitative correspondence between the comprehensive deterioration index and the five stability levels is clearly displayed in the form of horizontal segmented strips. The horizontal axis of the comprehensive deterioration index ranges from 0 to 1, and is divided into five continuous intervals: stable, slightly deteriorated, moderately deteriorated, severely deteriorated, and near instability. The warning threshold system includes a stability threshold. Mild degradation threshold moderate degradation threshold Severe degradation threshold Approaching the instability threshold All thresholds can be dynamically adjusted based on the lithology of the unstable rock mass, the dip angle of its structural surfaces, and the number of historical water level rises and falls, to adapt to engineering scenarios with different reservoir areas, lithologies, and structural surface conditions. Combining extensive indoor experimental and field monitoring data, this method adopts standardized threshold values: , , , When the overall deterioration index When the structural surfaces show no obvious damage, it is determined to be in a stable state; when At that time, slight deterioration appeared on the structural surface, which was judged as a mild deterioration state; when At that time, the degree of structural surface deterioration significantly worsened, and it was judged to be in a moderate deterioration state; when At that time, the structural surface was severely damaged, and it was judged to be in a state of severe deterioration; when At this point, the structural surface cracks are highly penetrating and the strength is significantly reduced, indicating a near-instability state. Corresponding inspection, monitoring, protection, and emergency response recommendations can be directly generated for different levels, achieving a complete transformation from quantitative calculation to qualitative early warning and then to engineering decision-making.

[0094] This embodiment, through coupling the damage chain mechanism, standardized formula calculation, engineering measured data support, multi-source monitoring information fusion, and dynamic threshold classification, can accurately characterize the damage evolution law, quantitatively describe the strength decay process, stably identify the deterioration level, and provide real-time early warning of instability risk. It can provide comprehensive, reliable, and quantitative technical support for the long-term stability evaluation, daily monitoring and prevention, engineering reinforcement design, and emergency response of dangerous rocks in reservoir areas.

[0095] Example 2: This example uses a typical reservoir bank dangerous rock as the monitoring object. Through multi-device collaborative data collection, centralized data transmission, unified back-end calculation and hierarchical early warning output, it realizes the full-process quantitative evaluation and risk warning of the structural surface strength deterioration of the dangerous rock.

[0096] like Figure 5As shown, the monitoring object in this embodiment is unstable rock mass 1, located on the upper part of a steep reservoir bank slope. It has a blocky structure with a controlling structural plane 2 between its bottom and the underlying bedrock. Tensile cracks form at its rear edge, representing a typical unstable rock mass in the reservoir area. The stability of unstable rock mass 1 is entirely controlled by the controlling structural plane 2. Under the coupled effects of periodic rises and falls in reservoir water level and external vibrations, the mechanical strength of structural plane 2 continuously deteriorates, making it the core focus of this monitoring and evaluation system. Reservoir water level 3 represents the operating water level of the reservoir area. During a single rise or fall in water level, the rock mass at structural plane 2 undergoes repeated soaking softening and shrinkage due to water loss, providing a continuous environmental dynamic for the deterioration process.

[0097] To achieve synchronous acquisition of multi-source data, this embodiment deploys five types of core monitoring equipment. The installation location and data transmission method of each device are designed around the key deterioration links of the unstable rock mass 1 and the main control structural surface 2. The water level monitoring unit 4 is installed on the water level gauge of the stable bank slope of the reservoir. The bottom of the device is fixed to the bedrock, and the top sensor probe is located within the water level fluctuation range. It collects the height data of the reservoir water level 3 in real time through the built-in pressure sensor. The sampling frequency is set to 1 time / hour, and the measurement accuracy can reach ±1cm. This unit can completely record parameters such as the rate of water level rise, rate of water level fall, duration of high water level maintenance, duration of low water level maintenance, single rise and fall amplitude, and number of dry and wet cycles. The data is transmitted to the data acquisition terminal 9 in real time via wired connection, providing the basic input for the calculation of water level rise and fall damage factors.

[0098] The vibration monitoring unit 5 is installed on a stable rock platform atop the unstable rock mass 1. It employs a high-sensitivity triaxial accelerometer with a sampling frequency of 100Hz and a measurement range of ±2g, capable of capturing weak vibration signals such as ship waves, coastal traffic loads, and micro-tremors. The device wirelessly transmits parameters such as vibration acceleration amplitude, frequency, and duration to the data acquisition terminal 9 in real time, providing dynamic data support for calculating vibration damage factors.

[0099] The crack displacement gauge 6 is installed on both sides of the tension crack at the rear edge of the unstable rock mass 1, with both ends fixed to the stable rock mass on both sides of the crack. It adopts a high-precision wire-type displacement sensor with a measurement accuracy of ±0.01mm and a sampling frequency of 1 time / minute. This device can monitor the opening displacement change of the crack in real time, calculate the displacement mutation rate index, and transmit the data to the data acquisition terminal 9 via wired connection, providing data for the displacement index in the multi-source response factor.

[0100] The acoustic emission sensor 7 is closely attached to the surface of the unstable rock mass 1 at the exposed position of the main control structure surface 2. It is a waterproof piezoelectric sensor with a sampling frequency of 1MHz. It can capture the acoustic emission signal generated by the rupture of micro-cracks inside the structure surface, count the number and activity of acoustic emission events, and transmit the data to the data acquisition terminal 9 via wired means to provide data for the acoustic emission index in the multi-source response factor.

[0101] Image acquisition unit 8 is installed on the observation platform on the opposite bank. It uses a high-definition industrial camera with a resolution of 1920×1080 and a sampling frequency of 1 time / day. The lens is directly facing the unstable rock mass 1 and the main control structural surface 2. It can acquire images of the structural surface in real time, extract the total crack area through image recognition technology, calculate the crack area ratio index, and transmit the data wirelessly to the data acquisition terminal 9 to provide data for the crack index in the multi-source response factor.

[0102] The data acquisition terminal 9 serves as the core for on-site data aggregation. It connects to the water level monitoring unit 4, vibration monitoring unit 5, crack displacement gauge 6, acoustic emission sensor 7, and image acquisition unit 8 via signal lines. It can receive, store, and transmit all monitoring data, with a data storage capacity of 1TB. It supports wireless 4G / 5G transmission and transmits data in real-time to the comprehensive degradation index calculation module 10. The terminal has a built-in data preprocessing program that performs noise reduction, filtering, and standardization on the raw data to ensure data quality meets the requirements of subsequent calculations.

[0103] The comprehensive deterioration index calculation module 10 is the core of the background data processing. It receives multi-source data transmitted from the data acquisition terminal 9, and calculates the water level rise and fall damage factor, vibration damage factor, structural surface control factor, and multi-source response factor in sequence according to the preset process. Then, it calculates the comprehensive deterioration index through a four-dimensional linear weighted model. The module has a complete built-in calculation program and parameter configuration, which can dynamically adjust the weight coefficients according to the geological conditions of the reservoir area to ensure that the calculation results match the actual engineering environment.

[0104] The early warning output module 11 is connected to the comprehensive deterioration index calculation module 10. It has a built-in five-level early warning threshold, corresponding to five states: stable, slightly deteriorated, moderately deteriorated, severely deteriorated, and near instability. The threshold can be dynamically adjusted according to the lithology of the unstable rock mass, the dip angle of the structural surface, and the number of historical water level cycles. The module can automatically determine the stability level based on the calculation results of the comprehensive deterioration index and output the corresponding early warning information and handling suggestions. The early warning information can be simultaneously transmitted to the prevention and control personnel through audible and visual alarms, SMS push, platform pop-ups, etc., to realize real-time early warning and graded handling of unstable rock risks.

[0105] This embodiment, through the organic combination of equipment collaboration, data transmission, background calculation and early warning output, fully covers the entire process of deterioration of unstable rock structures under the coupled effects of water level rise and fall and vibration. It can accurately quantify the degree of damage and timely identify instability risks, providing a reliable on-site monitoring and early warning solution for the stability evaluation and engineering control of unstable rocks in reservoir areas.

[0106] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter changes made to these embodiments within the spirit and principles of the present invention, without departing from the principles and spirit of the present invention, through conventional substitutions or to achieve the same function, fall within the scope of protection of the present invention.

Claims

1. A method for evaluating and warning of the deterioration of unstable rock structures in reservoir areas based on water level vibration coupling, characterized in that, Including the following: S1. Collect basic parameters of the unstable rock structure in the target reservoir area. The basic parameters include lithological parameters of the unstable rock mass, geometric parameters of the structure, time series data of water level rise and fall in the reservoir area, physical parameters of vibration disturbance, and multi-source response monitoring data of the structure. S2. Based on the reservoir water level rise and fall time series data, extract the dry-wet cycle number, soaking time, water loss time, and water level rise and fall amplitude characteristic parameters, and calculate the water level rise and fall damage factor. S3. Based on the physical parameters of vibration disturbance, extract the characteristic parameters of vibration frequency, acceleration amplitude, and vibration duration, and calculate the vibration damage factor. S4. Based on the geometric parameters of the structural surface, extract the characteristic parameters of the structural surface tilt angle, structural surface continuity rate, and structural surface roughness coefficient, and calculate the structural surface control factor. S5. Based on the multi-source response monitoring data of the structural surface, extract wave velocity parameters, acoustic emission parameters, crack image parameters, displacement parameters, and energy dissipation parameters, and calculate the multi-source response factor. S6. The water level rise and fall damage factor, vibration damage factor, structural surface control factor and multi-source response factor are weighted and fused to construct the comprehensive deterioration index of dangerous rock structure in the reservoir area. S7. Compare the comprehensive deterioration index with the dynamically corrected warning threshold, classify the stability level of the dangerous rock structure according to the comparison results, and output the warning result of the corresponding level.

2. The method according to claim 1, characterized in that, The water level rise and fall damage factor in S2 The damage evolution is determined using an exponential damage evolution formula, which is as follows: in, , , , All were determined through fitting experiments using indoor coupling degradation tests; The total number of wet and dry cycles experienced by the structural rock mass due to the periodic rise and fall of the reservoir water level; The duration of water immersion in the structural rock mass during a single water level rise or fall; This is the preset baseline soaking time; This represents the actual rise or fall of the water level during a single rise or fall process. This is the preset baseline water level rise and fall range.

3. The method according to claim 2, characterized in that, Vibration damage factor in S3 The damage accumulation formula is used to determine the extent of the damage, which is: in, , , , All were determined by fitting data through indoor vibration loading tests; This represents the actual amplitude of the vibrational acceleration acting on the rock mass at the structural surface. The preset reference vibration acceleration amplitude; This refers to the actual frequency of vibration acting on the rock mass at the structural surface; The preset reference vibration frequency; This refers to the actual duration of the vibration load acting on the rock mass of the structural surface. This is the preset reference vibration duration.

4. The method according to claim 3, characterized in that, S4 structural surface control factor It is determined by the linear weighted combination formula, which is: in, , , All of these are weighting coefficients preset based on engineering geological conditions; The angle between the main structural plane controlling the unstable rock and the horizontal plane; It is the ratio of the length of the structural surface through to the total length of the structural surface, representing the degree of structural surface continuity; The actual surface roughness coefficient of the structure is obtained through on-site measurement or indoor testing; This is the preset reference roughness coefficient.

5. The method according to claim 4, characterized in that, The multi-source response factor in S5 It is composed of five categories of indicators, namely wave velocity damage variable, acoustic emission activity index, crack area ratio index, displacement mutation rate index, and dissipation energy ratio index, which are linearly weighted and summed to comprehensively reflect the changes in the physical and mechanical response of the structural surface during the deterioration process.

6. The method according to claim 5, characterized in that, The wave velocity damage variable The relative change of P-wave velocity is determined by the formula, which is: in, The current longitudinal wave velocity of the rock mass at the structural plane is obtained through detection during the deterioration process. The initial longitudinal wave velocity of the rock mass at the structural surface before it has experienced water level fluctuations and vibration damage. Used to characterize the degree of structural damage caused by wave velocity attenuation.

7. The method according to claim 5, characterized in that, The crack area ratio index The crack area ratio is determined using the following formula: in, The total area of ​​all cracks extracted from the surface of a rock sample or the on-site monitoring area of ​​a dangerous rock using image recognition technology; This refers to the total surface area of ​​the rock sample used for testing or the total area of ​​the on-site monitoring area for dangerous rocks. Used to characterize the extent of crack propagation on the surface of a structural plane.

8. The method according to claim 5, characterized in that, The comprehensive degradation index in S6 The formula is determined using a four-dimensional factor linear weighting formula, as follows: in, , , , All are normalized weighting coefficients preset based on the geological conditions and engineering requirements of the reservoir area, and satisfy the following conditions: , The value ranges from 0 to 1, with a larger value indicating a higher degree of structural deterioration.

9. The method according to claim 8, characterized in that, The dynamic early warning threshold in S7 includes a stability threshold. Mild degradation threshold moderate degradation threshold Severe degradation threshold Approaching the instability threshold The threshold is adjusted in real time based on the lithological parameters of the dangerous rock mass, the dip angle parameters of the structural surface, and the number of historical water level rise and fall cycles, to adapt to the deterioration characteristics of different reservoir areas and different dangerous rock structural surfaces.

10. The method according to claim 9, characterized in that, The stability level in S7 is based on the comprehensive degradation index. The relative relationship with the dynamic early warning threshold is as follows: when At that time, the unstable rock structure was determined to be in a stable state; when At that time, the unstable rock structure was determined to be in a state of slight deterioration; when At that time, the unstable rock structure was determined to be in a state of moderate deterioration; when At that time, the unstable rock structure was determined to be in a state of severe deterioration; when At that time, the unstable rock structure was determined to be in a near-instability state.

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