A method for quickly identifying and early warning of scour-liquefaction coupling state of seabed
By deploying pore water pressure and resistivity monitoring units on the seabed, extracting pore pressure response and resistivity characteristics, and constructing judgment functions and exponents, rapid identification and early warning classification of seabed scour-liquefaction coupling state are achieved, solving the shortcomings of existing technologies in identification and early warning, and improving the accuracy of identification and management.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SANYA SCI & EDUCATION INNOVATION PARK WUHAN UNIV OF TECH
- Filing Date
- 2026-05-13
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies are insufficient to effectively identify and provide early warning of the coupling state between seabed scouring and liquefaction, lack the synergistic utilization of pore pressure response and resistivity evolution characteristics, struggle to distinguish between single anomalies and coupled anomalies, and lack unified identification and classification rules.
By deploying pore water pressure monitoring units and resistivity monitoring units on the seabed, the pore pressure response and resistivity evolution characteristics are extracted, and the judgment functions of the scour influence zone and liquefaction enhancement zone are constructed. The scour influence intensity, liquefaction development degree and coupling enhancement index are also constructed to achieve rapid identification and early warning classification of the seabed scour-liquefaction coupling state.
It improves the identification and risk assessment capabilities of seabed scour-liquefaction coupling states, provides more targeted early warning levels and state categories, and enhances the accuracy of seabed disaster risk management around offshore foundations and the basis for engineering response.
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Figure CN122192441A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of marine basic disaster monitoring technology, specifically involving a rapid identification and early warning classification method for seabed scour-liquefaction coupling state based on pore pressure response and resistivity evolution characteristics. Background Technology
[0002] Offshore wind turbine foundations, such as monopiles and jacket foundations, are constantly exposed to the combined effects of waves, currents, and cyclic loads in the marine environment. The seabed soil surrounding the foundations is prone to localized scouring, leading to a reduction in foundation embedment depth and weakened soil constraint near the foundation. Simultaneously, under the combined influence of repeated wave action and structural vibration, pore water pressure in the shallow seabed soil may continuously accumulate, potentially triggering liquefaction or dynamic softening. These two phenomena often occur simultaneously and in a coupled manner: on the one hand, seabed scouring alters the topography, stress boundaries, and soil force paths around the foundation, making localized soil more susceptible to pore pressure accumulation and liquefaction; on the other hand, liquefaction or softening reduces the seabed's scour resistance and shear strength, promoting further expansion of scour pits. Ultimately, this can lead to decreased foundation support stiffness, amplified dynamic response, and even tilting, excessive displacement, and service safety risks. Therefore, rapid identification and early warning classification of the seabed scour-liquefaction coupling state has become a crucial technical requirement for the safety monitoring of offshore wind turbine foundations.
[0003] Existing technologies offer numerous methods for monitoring and early warning of seabed scour, typically employing a comprehensive assessment based on information such as scour depth, scour range, foundation inclination, and structural frequency. For seabed liquefaction, existing technologies generally address it from the perspectives of pore water pressure response, wave load parameters, and soil deformation response. However, scour monitoring focuses on geometric changes in the seabed or the overall structural response, making it difficult to perceive the deterioration process of the dynamic properties of the soil near the foundation. It also fails to effectively characterize spatial continuity information such as the development of scour pits and the expansion of local exposed sections. Furthermore, liquefaction monitoring often revolves around pore pressure or numerical assessment, focusing on the identification of liquefaction itself, but it insufficiently reflects changes in the support conditions of the soil surrounding the foundation and the co-evolutionary relationship between the scour-affected zone and the liquefaction-sensitive zone.
[0004] To improve the reliability of early warnings, existing technologies have developed methods for joint monitoring of scour and structural condition. Existing schemes combine scour information with structural parameters such as frequency and tilt angle for safety warnings, attempting to improve accuracy through cross-verification of multi-source information. This type of method represents an improvement over single scour monitoring, as it can assist in risk identification from the perspective of changes in the overall dynamic response of the foundation. However, the fusion objects of these joint monitoring methods are primarily scour parameters and overall structural response parameters, focusing on safety warnings following changes in the foundation's structural condition. They have not yet established a further coupling identification mechanism between seabed scour and seabed liquefaction. In other words, existing monitoring methods do not consider seabed scour as a significant precursor to liquefaction risk, nor do they consider liquefaction as a significant trigger for scour expansion. Therefore, they lack specific identification indicators and graded early warning rules for the scour-liquefaction coupling state.
[0005] In summary, although existing monitoring methods can achieve seabed scour monitoring, seabed liquefaction determination, and joint early warning of scour and structural status, they are still mainly based on single disaster identification or single parameter monitoring. They lack a unified identification method for coupled states and also lack the synergistic utilization of pore pressure response and resistivity evolution characteristics, making it difficult to distinguish between single anomalies and coupled anomalies. Summary of the Invention
[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a rapid identification and early warning classification method for seabed scour-liquefaction coupling states based on pore pressure response and resistivity evolution characteristics. This method jointly extracts the pore water pressure response characteristics and resistivity spatiotemporal evolution characteristics of seabed soil during scour and liquefaction development processes, establishing rapid identification rules and early warning classification mechanisms for coupling states. This enables the differentiation and identification of single scour states, single liquefaction states, and scour-liquefaction coupling states, providing a basis for risk early warning and engineering treatment of seabed disasters around offshore foundations, and solving the problems existing in the aforementioned prior art.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: A rapid identification and early warning classification method for seabed scour-liquefaction coupling states includes the following steps: S1. Deploy pore water pressure monitoring units and resistivity monitoring units on the seabed around the offshore foundation to continuously collect pore pressure time history data and resistivity spatiotemporal data. S2. Preprocess the collected data to obtain the corrected pore pressure sequence and the corrected resistivity sequence; S3. Extract the normalized cumulative amplitude of pore pressure, pore pressure growth rate and pore pressure recovery hysteresis coefficient from the modified pore pressure sequence; extract the normalized resistivity offset, resistivity anomaly gradient, resistivity anomaly migration rate and resistivity recovery instability coefficient from the modified resistivity sequence. S4. Identify the scouring-affected zone based on the abnormal resistivity gradient and abnormal migration velocity, and identify the liquefaction-enhanced zone within the scouring-affected zone based on the cumulative pore pressure amplitude and pore pressure recovery hysteresis coefficient. The process of identifying the scour-affected zone includes: Define the scour impact zone The decision function is:
[0008] when The area continues to increase, and the boundary resistivity migrates at an abnormal rate. When the value exceeds the preset value, the scouring-affected area is determined to be in an expanding state;
[0009] The process of identifying liquefaction enhancement regions includes: Define the liquefaction enhancement zone The decision function is:
[0010] in, The threshold value for cumulative pore pressure. The threshold value for the pore pressure recovery hysteresis coefficient.
[0011] S5. Construct an index for the intensity of scouring impact, an index for the degree of liquefaction development, and an index for enhanced coupling. S6. Identify the state category based on the scouring impact intensity index, liquefaction development degree index, and coupling enhancement index, and output the corresponding warning level.
[0012] Furthermore, in S1, the pore water pressure monitoring unit and the resistivity monitoring unit are located in the same vertical direction.
[0013] Furthermore, in step S3, the process of extracting the normalized cumulative pore pressure amplitude, pore pressure growth rate, and pore pressure recovery hysteresis coefficient includes: Normalized cumulative pore pressure The calculation formula is as follows:
[0014] in, To correct the pore pressure sequence, Initial pore pressure, For the corresponding depth of effective overburden stress; Pore pressure growth rate The calculation formula is as follows:
[0015] Pore pressure recovery hysteresis coefficient after one load cycle or disturbance time window has ended The calculation formula is as follows:
[0016] in, This is the time required for the pore pressure to recover from its peak value to 90% of its initial state. This refers to the current representative wave cycle or a preset characteristic time window.
[0017] Furthermore, in step S3, the process of extracting the normalized resistivity offset, resistivity anomaly gradient, resistivity anomaly migration rate, and resistivity recovery instability coefficient includes: Normalized resistivity offset The calculation formula is as follows:
[0018] in, To correct the resistivity sequence, The initial resistivity; Resistivity Anomaly Gradient The calculation formula is as follows:
[0019] Let the location of the anomaly boundary be Then, within the surface control depth range, the resistivity anomaly gradient... The formula for calculating depth averaging is as follows:
[0020] in, This represents the resistivity anomaly gradient after depth averaging. To control the depth of the surface layer; Define the abnormal boundary location for:
[0021] in, The resistivity anomaly gradient threshold, For along A tiny spatial step in the direction; Then the resistivity anomaly migration rate The calculation formula is as follows:
[0022] Resistivity recovery instability coefficient The calculation formula is as follows:
[0023] in, This is a pre-defined shallow monitoring area.
[0024] Furthermore, in step S5, the process of constructing the scour influence intensity index includes: Define the intensity index of scour influence for:
[0025] in, To flush out the mean of the resistivity anomaly gradient within the affected region, For resistivity anomaly migration rate, The instability coefficient for the recovery of the region's average resistivity. These are the weighting coefficients for each component in the scour impact intensity index.
[0026] Furthermore, in S5, the process of constructing the liquefaction development level index includes: Define liquefaction development level indicators for:
[0027] in, This represents the cumulative average pore pressure within the liquefaction-enhanced zone. The average pore pressure growth rate, The average pore pressure recovery hysteresis coefficient is . These are the weighting coefficients for each component in the liquefaction development level index.
[0028] Furthermore, in S5, the process of constructing the coupling enhancement index includes: The synchronization enhancement coefficient is defined as:
[0029] in, This is the synchronization enhancement coefficient; The center translation parameter; For amplification parameters; The spatial overlap coefficient is defined as:
[0030] in, This is the spatial overlap coefficient; Then define the coupling enhancement index. for:
[0031] in, This is the coupling enhancement index.
[0032] Furthermore, in step S6, the process of identifying the state category includes: when At that time, the state category is determined to be scour-dominated state; when At that time, the state category was determined to be liquefaction-dominated; when At that time, the state category is identified as a coupled development state; when At that time, the state category is identified as a coupling-enhanced state; in, To flush out the significance threshold; The liquefaction significance threshold; A threshold is established for coupling; The coupling enhancement rate threshold; The process of outputting the corresponding warning level includes: Define the comprehensive risk index for:
[0033] in, These are the comprehensive risk indexes. Weighting coefficients; when At that time, the corresponding risk level is a Level 1 warning, and the disaster area is a minor anomaly. when At that time, the corresponding risk level output is a Level II warning, and the disaster scope is a significant development of a single disaster; when At that time, the corresponding risk level output is a Level 3 warning, and the disaster range is the coupled development of erosion and liquefaction; when At that time, the corresponding risk level output is a Level 4 warning, and the disaster range is a coupled and enhanced high-risk state.
[0034] Compared with the prior art, the beneficial effects of the present invention are: This invention, through a continuous technical chain of "scour impact zone identification → liquefaction enhancement zone identification → coupling enhancement index construction → state identification and early warning classification output," organically integrates the previously scattered scour, liquefaction, and media evolution information into a unified method. This not only improves the targeting of seabed scour-liquefaction coupling state identification but also enhances the ability to identify coupling development stages and risk escalation trends. In particular, by introducing pore pressure recovery hysteresis, resistivity anomaly boundary migration, the spatiotemporal overlap relationship between the scour impact zone and the liquefaction enhancement zone, and synchronous enhancement relationships, this invention solves the problems of existing technologies' inability to distinguish between single anomalies and coupled anomalies, and the difficulty in timely identifying coupling enhancement stages. This not only improves the depth of seabed disaster monitoring but also enhances the correspondence between early warning results and engineering response measures, enabling monitoring results to directly serve seabed risk management around offshore infrastructure. Furthermore, this invention can directly output more targeted early warning levels and state categories, providing a clear basis for subsequent measures such as localized scour prevention, key inspections, increased monitoring, or early warning escalation.
[0035] Specifically, this invention achieves a transformation from "single parameter limit alarm" to "state identification and hierarchical early warning driven by coupling mechanism". In existing seabed disaster monitoring, pore pressure is often used alone to judge liquefaction trend, and resistivity is often used alone to reflect changes in soil medium state. However, this invention places the two in a unified coupled identification framework, using pore pressure response to characterize the liquefaction development process, using resistivity evolution characteristics to characterize the scour impact zone expansion process, and using spatial overlap and synchronous enhancement mechanisms to characterize the coupling relationship between the two. This allows the early warning results to no longer be limited to judging whether it is abnormal, but to characterize whether it is a single disaster (which type of disaster it belongs to) or a coupled disaster, and whether the coupling is rapidly strengthening, which are more engineering-significant questions. Attached Figure Description
[0036] Figure 1 This is a schematic diagram of the overall process of the present invention; Figure 2 This is a top-view schematic diagram of the monitoring system layout in this invention; Figure 3 This is a side view schematic diagram of the monitoring system layout in this invention.
[0037] The attached figures are labeled as follows: 1. Resistivity monitoring unit; 2. Pore water pressure monitoring unit. Detailed Implementation
[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.
[0039] For easier understanding, please refer to Figure 1 This embodiment provides a rapid identification and early warning classification method for seabed scour-liquefaction coupling state based on pore pressure response and resistivity evolution characteristics, including the following steps: S1. Monitoring system deployment and raw data acquisition: In this embodiment, the monitoring points of the monitoring system are set up in the seabed around the marine foundation in a combination of circumferential partitioned differential arrangement and hierarchical coupled co-located monitoring unit arrangement, in order to obtain resistivity evolution information and pore water pressure response information corresponding to the seabed scour-affected area and liquefaction enhancement area.
[0040] For details, please refer to Figures 2 to 3 In this embodiment, a ring-shaped monitoring area is established around the seabed surrounding the offshore foundation. This monitoring area is divided circumferentially along the offshore foundation into a primary sensitive area, a secondary sensitive area, and a back-current area. The primary sensitive area is located on the upstream side of the foundation or in areas where the estimated risk of scour and liquefaction coupling is high. The secondary sensitive area is located in the transitional areas on either side of the primary sensitive area. The back-current area is located on the downstream side of the foundation or in areas where seabed disturbance is estimated to be weak. Within the primary, secondary, and back-current areas, several monitoring sections are arranged radially outward from the outer edge of the offshore foundation. The density of monitoring sections in the primary sensitive area is greater than that in the secondary and back-current areas, thus creating a differentiated arrangement that is denser in high-risk areas and moderately simplified in low-risk areas.
[0041] Along each monitoring section, monitoring points are arranged sequentially in the radial direction: near-base zone monitoring points, intermediate transition zone monitoring points, and far-field reference zone monitoring points. Each monitoring section is... This indicates that the monitoring points on the corresponding monitoring sections are... The monitoring points are arranged as follows: near-base zone monitoring points are located close to the outer edge of the foundation to prioritize monitoring changes in the surface medium state of the seabed in the vicinity of the foundation, the initial development of scour effects, and the response to shallow pore pressure anomalies; intermediate transition zone monitoring points are located outside the near-base zone monitoring points to identify the characteristics of scour influence zone boundary migration, anomaly zone expansion, and outward development of liquefaction enhancement zones; and far-field reference zone monitoring points are located at the outer end of the corresponding monitoring section to obtain the reference resistivity and reference pore pressure response of the relatively stable seabed area, serving as reference data under normal or uncoupled conditions.
[0042] Each monitoring point employs a layered coupled in-situ monitoring unit, meaning that each monitoring point has a pore water pressure monitoring unit 2 and a resistivity monitoring unit 1 located in the same vertical direction. During the monitoring process, pore pressure time history data and resistivity spatiotemporal data are continuously collected. Specifically, the layered coupled in-situ monitoring unit is inserted into the seabed soil, and resistivity acquisition units (resistivity monitoring unit 1) and pore water pressure acquisition units (pore water pressure monitoring unit 2) are set up layer by layer along the depth direction. The surface resistivity acquisition layer is set at or below the seabed surface to collect resistivity change information of the surface medium and identify the boundary of the scour influence zone and its migration process. The shallow pore water pressure acquisition layer is set below the surface resistivity acquisition layer to collect pore pressure accumulation, growth, and recovery hysteresis information of the shallow seabed soil under cyclic loading to identify liquefaction enhancement zones. Furthermore, a reference acquisition layer (not shown in the figure) is also included at a deeper depth to obtain background pore pressure or background resistivity information of more stable layers. The resistivity acquisition unit and the pore water pressure acquisition unit are arranged in layers along the same main body of the monitoring unit to ensure the spatial correspondence between the resistivity anomaly identification results and the pore pressure response results, thereby improving the accuracy of the overlapping identification of the scour-affected zone and the liquefaction enhancement zone.
[0043] Furthermore, at least three monitoring sections are set up in the main sensitive area, at least two monitoring sections are set up in the secondary sensitive area, and at least one monitoring section is set up in the control area. At least three monitoring points are set up on each monitoring section, corresponding to the near-base area, intermediate transition area, and far-field reference area, respectively; at least one resistivity acquisition layer and one pore water pressure acquisition layer are set up in each monitoring point, preferably multiple resistivity acquisition layers and multiple pore pressure acquisition layers, to improve the accuracy of abnormal boundary identification and liquefaction enhancement area identification (two layers are shown as an example in the figure).
[0044] S2. Monitoring data preprocessing: To eliminate the effects of sea state fluctuations, tidal changes, and instrument zero drift, the raw acquired data underwent baseline correction and short-time window smoothing to obtain the corrected pore pressure sequence. and corrected resistivity sequence ,in, For depth coordinates, The horizontal coordinates along the monitoring section, For time.
[0045] S3. Key Response Feature Extraction: S31. Extraction of pore pressure response evolution features: According to the modified pore pressure sequence Extracting the normalized cumulative pore pressure amplitude pore pressure growth rate and pore pressure recovery hysteresis coefficient The specific process is as follows: Normalized cumulative pore pressure The calculation formula is as follows:
[0046] in, Initial pore pressure, This represents the effective overburden stress at the corresponding depth.
[0047] Pore pressure growth rate The calculation formula is as follows:
[0048] Pore pressure recovery hysteresis coefficient after one load cycle or disturbance time window has ended The calculation formula is as follows:
[0049] in, This is the time required for the pore pressure to recover from its peak value to 90% of its initial state. The current representative wave cycle or preset characteristic time window; the pore pressure recovery hysteresis coefficient reflects the degree of decline in the soil's drainage recovery capacity.
[0050] S32, Resistivity Evolution Feature Extraction: Based on the modified resistivity sequence Extracting normalized resistivity offset resistivity anomaly gradient Resistivity anomaly migration rate and resistivity recovery instability coefficient The specific process is as follows: Normalized resistivity offset The calculation formula is as follows:
[0051] in, The initial resistivity.
[0052] Resistivity Anomaly Gradient The calculation formula is as follows:
[0053] Let the location of the anomaly boundary be Then within the surface control depth range For resistivity anomaly gradient The formula for calculating depth averaging is as follows:
[0054] in, This represents the resistivity anomaly gradient after depth averaging. To control the depth of the surface layer.
[0055] Define the abnormal boundary location for:
[0056] in, The resistivity anomaly gradient threshold, For along A tiny spatial step in the direction.
[0057] Then the resistivity anomaly migration rate The calculation formula is as follows:
[0058] Resistivity recovery instability coefficient The calculation formula is as follows:
[0059] in, The shallow monitoring area is preset; the resistivity recovery instability coefficient reflects the degree of drastic change in the overall resistivity of the area and whether the state of the seabed medium is still in a rapid change phase.
[0060] S4. Identification of the scouring-affected zone and the liquefaction-increased zone: S41. Identification of the scour-affected area: Based on resistivity anomaly gradient and resistivity anomaly migration rate Identify the scour impact zone (boundary of the seabed surface anomaly zone).
[0061] Define the scour impact zone The decision function is:
[0062] when The area continues to increase, and the boundary resistivity migrates at an abnormal rate. When the value exceeds the preset value, the scouring-affected area is determined to be in an expanding state.
[0063] S42, Identification of liquefaction enhancement zone: In the scour-affected area Within the range, the pore pressure response is further analyzed based on the cumulative amplitude of pore pressure and the pore pressure recovery hysteresis coefficient to identify the liquefaction enhancement zone.
[0064] Define the liquefaction enhancement zone The decision function is:
[0065] in, The threshold value for cumulative pore pressure. The threshold value for the pore pressure recovery hysteresis coefficient.
[0066] By identifying the scouring influence zone of the seabed surface through resistivity anomaly gradient and anomaly boundary migration characteristics, and then extracting the pore pressure cumulative amplitude and pore pressure recovery hysteresis characteristics within the scouring influence zone, the liquefaction enhancement zone can be identified. This allows the scouring identification and liquefaction identification to be no longer separated, and achieves a hierarchical identification process of first identifying the scouring range and then identifying the liquefaction development state within that range.
[0067] S5. Construction of Coupled Identification Indicators: S51, Constructing Scouring Influence Indicators : Define the intensity index of scour influence for:
[0068] in, To flush out the mean of the resistivity anomaly gradient within the affected region, For resistivity anomaly migration rate, The instability coefficient for the recovery of the region's average resistivity. These are the weighting coefficients of each component in the scour influence intensity index, representing the relative contribution of each component to the scour influence intensity.
[0069] S52, Constructing indicators for the development level of liquefaction : Define liquefaction development level indicators for:
[0070] in, This represents the cumulative average pore pressure within the liquefaction-enhanced zone. The average pore pressure growth rate, The average pore pressure recovery hysteresis coefficient is . These are the weighting coefficients of each component in the liquefaction development level index, representing the relative contribution of each component to the liquefaction development level.
[0071] S53, Constructing a Coupling Enhancement Index : Specifically, the coupling enhancement index It should at least include the spatiotemporal overlap and synchronous enhancement relationship between the scour-affected zone and the liquefaction-enhanced zone.
[0072] Only when both the intensity of scouring and the degree of liquefaction development increase simultaneously is it considered a coupled enhancement. and Let represent the average pore pressure growth rate and the resistivity anomaly boundary migration rate, respectively. Their product can express whether liquefaction and scouring evolve together within the same time window. Therefore, the threshold effect is expressed using a sigmoid function as follows: The synchronization enhancement coefficient is defined as:
[0073] in, The synchronization enhancement coefficient is used to characterize the degree of synergistic enhancement between liquefaction development and scouring effects within the same time window; The center translation parameter is used to characterize the product reference value when the synergistic enhancement of pore pressure response and resistivity anomaly migration reaches a significant state; The amplification parameter controls the steepness of the transition of the synchronization enhancement coefficient near the product reference value; the center translation parameter... and amplification parameters Both are determined by the sample distribution of coupling features under different states.
[0074] The spatial overlap coefficient is defined as:
[0075] in, The spatial overlap coefficient is defined as the liquefaction enhancement region. and the scour-affected area The ratio reflects the spatial proportion of the liquefaction enhancement zone relative to the scour-affected zone.
[0076] Then define the coupling enhancement index. for:
[0077] When scouring and liquefaction are enhanced simultaneously It will rise significantly; if it is only a single flush, then If the overlap between the liquefaction enhancement zone and the scouring influence zone is low, then the overall coupling index will not be artificially high, and vice versa; if the overlap is low, then... If the level is low, it is not appropriate to classify it as a coupled disaster.
[0078] S6. Status identification and early warning hierarchical output: S61, State Identification Output: according to The relative size relationships used to determine the current state are shown in Table 1 below: Table 1. Identification of Seabed Erosion / Liquefaction Status
[0079] In the above table, To flush out the significance threshold; The liquefaction significance threshold; A threshold is established for coupling; The above thresholds are the coupling enhancement rate thresholds; all of these thresholds were obtained by numerical simulation, model test, historical monitoring data or known working condition samples.
[0080] S62. Early warning classification output: Define the comprehensive risk index for:
[0081] in, These are the weighting coefficients of the comprehensive risk index, and represent the relative contribution of each component to the comprehensive risk assessment.
[0082] according to The size relationship is determined and the current risk level and disaster scope are output as shown in Table 2 below: Table 2. Early Warning Level Comparison Table
[0083] By constructing an identification system that includes scour impact intensity index, liquefaction development degree index, and coupling enhancement index, the coupling enhancement index simultaneously characterizes the spatiotemporal overlap and synchronous enhancement relationship between the scour impact area and the liquefaction enhancement area. This system can effectively distinguish between a single scour state, a single liquefaction state, and a scour-liquefaction coupled development state, avoiding misjudging local short-term scour anomalies as coupled disasters and also avoiding misjudging isolated liquefaction responses far from the scour impact area as coupled instability.
[0084] Although the present invention has been described using the above preferred embodiments, it is not intended to limit the scope of protection of the present invention. Any changes and modifications made by those skilled in the art to the above embodiments without departing from the spirit and scope of the present invention shall still fall within the scope of protection of the present invention.
Claims
1. A rapid identification and early warning classification method for seabed erosion-liquefaction coupling state, characterized in that, Includes the following steps: S1. Deploy pore water pressure monitoring units and resistivity monitoring units on the seabed around the offshore foundation to continuously collect pore pressure time history data and resistivity spatiotemporal data. S2. Preprocess the collected data to obtain the corrected pore pressure sequence and the corrected resistivity sequence; S3. Extract the normalized cumulative amplitude of pore pressure, pore pressure growth rate and pore pressure recovery hysteresis coefficient from the modified pore pressure sequence; extract the normalized resistivity offset, resistivity anomaly gradient, resistivity anomaly migration rate and resistivity recovery instability coefficient from the modified resistivity sequence. S4. Identify the scouring-affected zone based on the abnormal resistivity gradient and abnormal migration velocity, and identify the liquefaction-enhanced zone within the scouring-affected zone based on the cumulative pore pressure amplitude and pore pressure recovery hysteresis coefficient. The process of identifying the scour-affected zone includes: Define the scour impact zone The decision function is: , when The area continues to increase, and the boundary resistivity migrates at an abnormal rate. When the value exceeds the preset value, the scouring-affected area is determined to be in an expanding state; The process of identifying liquefaction enhancement regions includes: Define the liquefaction enhancement zone The decision function is: ， in, The threshold value for cumulative pore pressure. The threshold value for the pore pressure recovery hysteresis coefficient; S5. Construct an index for the intensity of scouring impact, an index for the degree of liquefaction development, and an index for enhanced coupling. S6. Identify the state category based on the scouring impact intensity index, liquefaction development degree index, and coupling enhancement index, and output the corresponding warning level.
2. The rapid identification and early warning classification method for seabed erosion-liquefaction coupling state according to claim 1, characterized in that, In S1, the pore water pressure monitoring unit and the resistivity monitoring unit are located in the same vertical direction.
3. The rapid identification and early warning classification method for seabed erosion-liquefaction coupling state according to claim 1, characterized in that, In step S3, the process of extracting the normalized cumulative pore pressure amplitude, pore pressure growth rate, and pore pressure recovery hysteresis coefficient includes: Normalized cumulative pore pressure The calculation formula is as follows: ， in, To correct the pore pressure sequence, Initial pore pressure, For the corresponding depth of effective overburden stress; Pore pressure growth rate The calculation formula is as follows: ， Pore pressure recovery hysteresis coefficient after one load cycle or disturbance time window has ended The calculation formula is as follows: , in, This is the time required for the pore pressure to recover from its peak value to 90% of its initial state. This refers to the current representative wave cycle or a preset characteristic time window.
4. The rapid identification and early warning classification method for seabed erosion-liquefaction coupling state according to claim 1, characterized in that, In step S3, the process of extracting the normalized resistivity offset, resistivity anomaly gradient, resistivity anomaly migration rate, and resistivity recovery instability coefficient includes: Normalized resistivity offset The calculation formula is as follows: ， in, To correct the resistivity sequence, The initial resistivity; Resistivity Anomaly Gradient The calculation formula is as follows: , Let the location of the anomaly boundary be Within the surface control depth range, the resistivity anomaly gradient... The formula for calculating depth averaging is as follows: , in, This represents the resistivity anomaly gradient after depth averaging. To control the depth of the surface layer; Define the abnormal boundary location for: ， in, The resistivity anomaly gradient threshold, For along A tiny spatial step in the direction; Then the resistivity anomaly migration rate The calculation formula is as follows: , Resistivity recovery instability coefficient The calculation formula is as follows: , in, This is a pre-defined shallow monitoring area.
5. The rapid identification and early warning classification method for seabed erosion-liquefaction coupling state according to claim 1, characterized in that, In step S5, the process of constructing the scour influence intensity index includes: Define the intensity index of scour influence for: , , in, To flush out the mean of the resistivity anomaly gradient within the affected region, For resistivity anomaly migration rate, The instability coefficient for the recovery of the region's average resistivity. These are the weighting coefficients for each component in the scour impact intensity index.
6. The rapid identification and early warning classification method for seabed erosion-liquefaction coupling state according to claim 5, characterized in that, In S5, the process of constructing the liquefaction development level index includes: Define liquefaction development level indicators for: ， in, This represents the cumulative average pore pressure within the liquefaction-enhanced zone. The average pore pressure growth rate, The average pore pressure recovery hysteresis coefficient is . These are the weighting coefficients for each component in the liquefaction development level index.
7. The rapid identification and early warning classification method for seabed erosion-liquefaction coupling state according to claim 6, characterized in that, In S5, the process of constructing the coupling enhancement index includes: The synchronization enhancement coefficient is defined as: , in, This is the synchronization enhancement coefficient; The center translation parameter; For amplification parameters; The spatial overlap coefficient is defined as: ， in, This is the spatial overlap coefficient; The coupling enhancement index is then defined as: , in, This is the coupling enhancement index.
8. The rapid identification and early warning classification method for seabed erosion-liquefaction coupling state according to claim 7, characterized in that, In step S6, the process of identifying the state category includes: when At that time, the state category is determined to be scour-dominated state; when At that time, the state category was determined to be liquefaction-dominated; when At that time, the state category is identified as a coupled development state; when At that time, the state category is identified as a coupling-enhanced state; in, To flush out the significance threshold; The liquefaction significance threshold; A threshold is established for coupling; The coupling enhancement rate threshold; The process of outputting the corresponding warning level includes: Define the comprehensive risk index for: , in, These are the comprehensive risk indexes. Weighting coefficients; when At that time, the corresponding risk level is a Level 1 warning, and the disaster area is a minor anomaly. when At that time, the corresponding risk level output is a Level II warning, and the disaster scope is a significant development of a single disaster; when At that time, the corresponding risk level output is a Level 3 warning, and the disaster range is the coupled development of erosion and liquefaction; when At that time, the corresponding risk level output is a Level 4 warning, and the disaster range is a coupled and enhanced high-risk state.