Safety assessment method for ground wire falling into water during line removal construction of river-crossing line

Abstract

The invention relates to the technical field of power transmission line engineering safety, and discloses a river-crossing line clearing construction ground wire falling-into-water safety assessment method, which comprises the following steps: obtaining hydrodynamic data and riverbed landform data of a construction river section, and constructing an environmental mechanics characteristic field containing environmental mechanics parameters based on the data; in the environmental mechanical characteristic field, executing forward dynamic simulation of the ground wire falling into water to obtain the maximum tower top tension as a risk index; and executing accompanying state inversion and risk source sensitivity analysis by taking the tower top maximum tension as a target function so as to calculate the sensitivity of the target function to each environmental mechanical parameter in the environmental mechanical characteristic field. According to the method, the adjoint state inversion method is introduced and the environmental mechanics characteristic field is constructed, so that the traditional mass repeated simulation is replaced with extremely high calculation efficiency, and the accuracy of the evaluation result is remarkably improved through fine modeling of the vortex-induced effect and the anchoring risk.

Description

Technical Field

[0001] This invention relates to the field of power transmission line engineering safety technology, specifically a method for assessing the safety of conductors and ground wires falling into water during the dismantling of cross-river power transmission lines. Background Technology

[0002] Overhead transmission lines, especially those spanning long distances across rivers and canyons, need to be dismantled at the end of their lifespan. Conductor and ground wire removal is an extremely high-risk part of the entire project. During this process, if the conductor or ground wire breaks accidentally or detaches due to improper handling, it will fall into the water at high speed under the influence of gravity and residual tension. This dynamic process generates enormous impact loads, which are transmitted to the tower structures at both ends of the line, potentially posing a serious threat to the stability of the tower foundations and even triggering a chain reaction of structural damage.

[0003] To ensure construction safety, the engineering community typically conducts preliminary risk assessments of the conductor's descent into the water. However, existing assessment methods have significant limitations. On one hand, some methods rely on heavily simplified analytical models, which often neglect the complex hydrodynamic effects on the conductor as it moves through the water, such as fluid resistance and vortex-induced vibrations. Furthermore, these models fail to quantify the likelihood of the conductor snagging or anchoring to the complex and variable riverbed. This oversimplification leads to significant discrepancies between the assessment results and actual conditions, making it difficult to accurately predict the true peak impact force.

[0004] On the other hand, in pursuit of higher accuracy, some assessment methods have turned to complex numerical simulation techniques, such as combining the finite element method with computational fluid dynamics. While these methods can theoretically simulate physical processes more realistically, they face enormous computational cost challenges. The final impact force of the conductor after it falls into the water is influenced by a large number of uncertain environmental factors, such as water flow velocity, riverbed topography, and anchoring location. To comprehensively assess the risk, a massive amount of repeated simulation calculations of various combinations of these uncertain parameters are required, i.e., Monte Carlo analysis. The computational load of this method grows exponentially and is extremely time-consuming, making it almost infeasible within the tight time windows required by actual engineering projects, and unable to provide rapid and effective decision support for on-site construction. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for assessing the safety of conductors and ground wires falling into water during the dismantling of cross-river lines. This method solves the problem in existing technologies where the contradiction between computational efficiency and model accuracy makes it difficult to quickly and accurately identify and quantify the location of key risk sources when assessing the risk of conductors and ground wires falling into water.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines, comprising the following steps:

[0007] Obtain hydrodynamic data and riverbed topography data of the construction section, and construct an environmental mechanical characteristic field containing environmental mechanical parameters based on the data;

[0008] In the aforementioned environmental mechanical characteristic field, a forward dynamic simulation of the conductor falling into the water is performed to obtain the maximum tension at the top of the tower as a risk indicator;

[0009] Using the aforementioned maximum tension at the top of the tower as the objective function, an adjoint state inversion and risk source sensitivity analysis are performed to calculate the sensitivity of the objective function to environmental mechanical parameters at various points in the environmental mechanical characteristic field.

[0010] A comprehensive assessment is conducted based on the aforementioned sensitivity to identify key risk sources that significantly affect the maximum tension at the top of the tower.

[0011] Preferably, the construction of the environmental mechanical characteristic field includes:

[0012] Construct a basic fluid velocity potential field;

[0013] Construct a vortex-induced energy injection rate field;

[0014] Construct a stochastic anchored potential well field.

[0015] Preferably, the construction of the vortex-induced effect energy injection rate field includes:

[0016] Calculate the Reynolds number and Strouhal number at any position within the field based on the aforementioned basic fluid velocity potential field;

[0017] The vortex-induced energy injection rate field is calculated using a pre-calibrated mapping function from Reynolds number and Strouhal number to energy injection rate.

[0018] Preferably, the random anchoring potential field consists of two components: anchoring probability and maximum static friction force. The anchoring probability is determined based on the local geometric characteristics of the riverbed, and the maximum static friction force is determined based on the geological properties of the riverbed.

[0019] Preferably, in the forward dynamics simulation, the hydrodynamic force on the conductor is calculated using the Morison equation, and the effective drag coefficient in the Morison equation is corrected by an increment related to the accumulated vortex-induced energy, which is obtained by integrating the energy injection rate field of the vortex-induced effect along the conductor's trajectory.

[0020] Preferably, the accompanying state inversion and risk source sensitivity analysis includes:

[0021] Based on the control equations of the aforementioned forward dynamics simulation, construct its corresponding adjoint equation set;

[0022] Solve the adjoint equations by inverse integration from the end of the simulation to obtain the time series of the adjoint state vector.

[0023] Preferably, the method further includes:

[0024] Based on the solved adjoint state vector, a three-dimensional risk source sensitivity map is generated to quantify the contribution of risk sources.

[0025] Preferably, the comprehensive evaluation includes:

[0026] The three-dimensional risk source sensitivity map is superimposed with the random anchored potential well field for analysis to identify the key risk sources.

[0027] Preferably, the method further includes:

[0028] Using the sensitivity as gradient information, the controllable construction parameters in the construction plan are iteratively adjusted through optimization algorithms to minimize the maximum tension at the top of the tower.

[0029] A safety assessment system for conductors falling into water during the dismantling of cross-river power lines includes:

[0030] The environmental mechanics feature field construction module is used to acquire hydrodynamic data and riverbed topography data of the construction section, and construct an environmental mechanics feature field containing environmental mechanics parameters based on the data.

[0031] The dynamics simulation engine module is used to perform forward dynamics simulation of the conductor falling into the water process in the environmental mechanical characteristic field to obtain the maximum tension at the top of the tower as a risk indicator.

[0032] The accompanying state inversion and sensitivity analysis module is used to perform accompanying state inversion and risk source sensitivity analysis with the aforementioned maximum tension at the top of the tower as the objective function, so as to calculate the sensitivity of the objective function to the environmental mechanical parameters at various points in the environmental mechanical characteristic field.

[0033] The optimization and decision support module is used to perform a comprehensive evaluation based on the sensitivity to identify key risk sources that have a significant impact on the maximum tension at the top of the tower.

[0034] This invention provides a method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines. It has the following beneficial effects:

[0035] 1. This invention, by introducing adjoint state inversion and sensitivity analysis methods, requires only one forward dynamic simulation and one adjoint state inversion to obtain the sensitivity of the maximum tension at the tower top, serving as a risk indicator, to all environmental mechanical parameters across the entire field. Compared to traditional Monte Carlo methods or parameter scanning methods that require thousands of repeated calculations to obtain similar information, this invention achieves an order-of-magnitude improvement in computational efficiency, thereby making comprehensive risk assessment of large-scale, highly complex underwater environments engineering-feasible.

[0036] 2. This invention constructs an environmental mechanical characteristic field, particularly the eddy-induced energy injection rate field and the stochastic anchoring potential well field, to structurally quantify complex fluid-structure interaction effects and uncertain riverbed entrapment risks. Furthermore, in the dynamic simulation, the accumulated eddy-induced energy is used to dynamically correct the water resistance coefficient in the Morison equation, enabling the simulation model to more realistically reflect the force process of the conductor in complex water flow, significantly improving the accuracy and reliability of the assessment results.

[0037] 3. This invention can generate an intuitive three-dimensional risk source sensitivity map, which directly quantifies and visualizes the impact of environmental parameter changes at any location in the riverbed and water body on the final tower top tension. Through this map, engineers can quickly and accurately identify the geographical locations of key risk sources that pose the greatest threat to construction safety, providing a direct and clear basis for developing targeted contingency plans or adjusting construction routes, thus changing the previous reliance on experience or blind trial-and-error. Attached Figure Description

[0038] Figure 1 This is a diagram illustrating the method steps of the present invention;

[0039] Figure 2 This is a system architecture diagram of the present invention. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see the appendix Figure 1 This invention provides a method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines, comprising the following steps:

[0042] Acquire hydrodynamic data and riverbed topography data of the construction section, and construct an environmental mechanical characteristic field containing environmental mechanical parameters based on the data;

[0043] In the environmental mechanical characteristic field, a forward dynamic simulation of the conductor falling into the water is performed to obtain the maximum tension at the top of the tower as a risk indicator;

[0044] Using the aforementioned maximum tension at the top of the tower as the objective function, we perform adjoint state inversion and risk source sensitivity analysis to calculate the sensitivity of the objective function to environmental mechanical parameters at various points in the environmental mechanical characteristic field.

[0045] A comprehensive assessment based on sensitivity is conducted to identify key risk sources that have a significant impact on the maximum tension at the top of the tower.

[0046] Based on the solved adjoint state vector, a three-dimensional risk source sensitivity map is generated to quantify the contribution of risk sources.

[0047] By using sensitivity as gradient information, the controllable construction parameters in the construction plan are iteratively adjusted through optimization algorithms to minimize the maximum tension at the top of the tower.

[0048] In the process of preparing environmental data and constructing environmental mechanical characteristic fields, this step aims to transform the on-site physical environment into structured data that can be efficiently computed by computers.

[0049] Environmental data was acquired and preprocessed. A gridded survey of the construction section was conducted using a shipborne acoustic Doppler current profiler (ADCP), collecting a series of discrete data points containing three-dimensional coordinates and corresponding velocity vectors. Simultaneously, a high-resolution digital elevation model (DEM) of the riverbed was acquired using a multibeam echo sounder. Combined with side-scan sonar images, key geomorphic features on the riverbed, such as rocks, gullies, and large sediments, were identified and labeled, recording their location, geometric dimensions, and material properties. Coordinate system registration, noise filtering, and outlier removal were performed on the collected raw data to form a standardized input dataset.

[0050] To construct the basic fluid velocity potential field, preprocessed discrete velocity data points are used as input, and a spatial interpolation algorithm is employed to generate a continuous three-dimensional velocity field covering the entire simulation region. The specific implementation of this spatial interpolation algorithm includes, but is not limited to, Kriging interpolation or inverse distance weighted interpolation. The generated continuous velocity field is stored in the form of three-dimensional grid data, and each grid node stores the velocity vector of that point.

[0051] A vortex-induced energy injection rate field is constructed. This field is used to macroscopically characterize the energy gained by the conductor / ground wire due to vortex-induced vibration in the flow field, for any position within the field. First, calculate the local Reynolds number at that point. and Strouhal :

[0052] ;

[0053] ;

[0054] in, This is the water flow velocity vector at that point. The diameter of the ground wire, The kinematic viscosity of water, The natural vibration frequency of the conductor in water is then determined by a pre-calibrated mapping function. Calculate the energy injection rate The mapping function The specific implementation can be a look-up table built based on a large amount of computational fluid dynamics (CFD) simulation or tank experiment data, or a fitted polynomial function.

[0055] A stochastic anchoring potential well field is constructed to quantify the risk of the conductor getting caught when it comes into contact with the riverbed. For any location on the riverbed ( Define a risk tuple Among them, anchoring probability It is a function of local geometric features such as slope, curvature, and roughness index calculated based on a riverbed digital elevation model. The sharper and more complex the terrain, the higher this probability value, representing the maximum static friction or locking force. The value is set based on the geological properties of the location, such as rocks and sediment, and reflects the maximum constraint capacity that the point can provide.

[0056] In performing forward dynamics simulation and risk indicator acquisition, this step simulates the physical behavior of conductors and ground wires under specific construction schemes.

[0057] Initialize the dynamic model by abstracting and discretizing the conductor and ground wire as a component. A flexible multibody system composed of multiple mass points, which are connected by nonlinear spring-damping units. The physical properties of the conductor, such as mass per unit length, elastic modulus, and diameter, and the initial state, such as failure tower number, initial tension, and initial release velocity, are input according to the construction plan.

[0058] Iteratively solving the dynamic equations using numerical integration methods within a time step Within, for each particle in the system The state is updated, and this process is repeated cyclically until the simulation ends. Within one cycle, the state of the mass is updated. Calculate the resultant force acting on it, which includes: internal tension and damping force. ;gravity Hydrodynamics ; and contact with the riverbed and anchoring force. .

[0059] Hydrodynamics The calculation is particularly crucial, as it employs the Morison equation and considers the drag-inducing effect of vortex-induced vibration:

[0060] ;

[0061] in, The density of water, Let the area of ​​the conductor be the projected area perpendicular to the water flow. The relative velocity between the water flow and the particle. It is dynamically changing, and its value is determined by the foundation resistance coefficient. and the accumulated vortex energy Related increments Composition. Accumulated energy The integral is updated along the trajectory of the particle at each time step.

[0062] When the vertical coordinate of particle i is lower than the riverbed elevation at its horizontal position, the anchoring judgment logic is triggered. The system generates a random number and compares it with the anchoring probability obtained from the random anchoring potential well field. A comparison is made to determine whether an anchoring event has occurred. If it has, a locking force, in the opposite direction to the tendency of motion and not exceeding the maximum locking force, is applied to the particle. anchoring force .

[0063] The system updates the state and records the results. Using the calculated resultant force, the position and velocity of the particles are updated through a numerical integration scheme, such as the Verlet integral method or the fourth-order Runge-Kutta method. The simulation terminates when the preset maximum duration is reached or the total kinetic energy of the system falls below the stability threshold. Throughout the simulation, the system continuously records the motion trajectories of all particles and the tension time history at the connection point at the top of the tower. And extract the maximum value from it as the core risk indicator. .

[0064] In performing adjoint state inversion and risk source sensitivity analysis, this step aims to efficiently trace the root physical causes of high risk.

[0065] Construct the adjoint system and express the entire set of ordinary differential equations for forward dynamics simulation in state-space form. ,in This is the system state vector containing the positions and velocities of all particles. Given the system parameter set, the maximum tension is obtained by performing forward dynamic simulation and risk indicator acquisition step by step. For the objective function, construct its corresponding adjoint equation system: .

[0066] Solve the adjoint equation and use the state trajectory q(t) recorded by forward simulation, starting from the simulation end time. Initially, the adjoint equations are solved by inverse integration to obtain the adjoint state vector. The solution over the entire time domain.

[0067] Calculate the sensitivity and generate a spectrum. Using the obtained adjoint vector, apply the integral formula... Calculate the objective function For any parameter The sensitivity of the parameters is as follows. Here, parameter pk specifically refers to a physical quantity at a specific spatial location in the environmental mechanical characteristic field, such as the anchoring force of a riverbed grid cell or the flow velocity of a fluid grid cell. After calculating the sensitivity of the corresponding parameters of all grid cells in the simulation area, these sensitivity values ​​are mapped back to three-dimensional space to generate a visualized risk source sensitivity map. .

[0068] In the process of conducting a comprehensive assessment and optimizing the construction plan, this step aims to identify the sources of risk and propose improvement measures.

[0069] Identify key risk sources, calculate the sensitivity of each step, and generate a risk source sensitivity map from the generated map. Constructing a stochastic anchored potential well field using the steps described above. Areas exhibiting both high sensitivity values ​​and high anchoring probability or high locking force in space through overlay or correlation analysis are identified as key risk sources posing the greatest threat to this construction plan.

[0070] The construction plan is iteratively optimized by defining adjustable parameters such as initial tension and key control points of the tension curves of the two traction machines as optimization variables. The gradient of the objective function for these optimization variables is calculated using the adjoint method. This data is then fed into a gradient-based optimization algorithm. The specific implementation of this algorithm includes, but is not limited to, gradient descent, conjugate gradient, or L-BFGS. The algorithm iteratively updates... To minimize the objective function .

[0071] The system outputs optimization results and an evaluation report. Once the optimization algorithm converges, the system outputs a set of optimal construction parameter combinations that minimize the maximum tension at the top of the tower. At the same time, a comprehensive evaluation report is generated, which includes a comparison of risk indicators before and after optimization, an analysis of the location and attributes of key risk sources, and the final recommended construction scheme. As another implementation method, this method also supports users to input multiple different construction schemes. The system performs a fast forward simulation on each scheme and lists the risk indicators for users to make horizontal comparison and selection decisions.

[0072] Please see the appendix Figure 2 The present invention also provides a safety assessment system for conductors falling into water during the dismantling of cross-river power lines, comprising:

[0073] The environmental mechanics feature field construction module is used to acquire hydrodynamic data and riverbed topography data of the construction section, and construct an environmental mechanics feature field containing environmental mechanics parameters based on the data.

[0074] The dynamics simulation engine module is used to perform forward dynamics simulation of the conductor falling into the water process in an environmental mechanical characteristic field, so as to obtain the maximum tension at the top of the tower as a risk indicator.

[0075] The accompanying state inversion and sensitivity analysis module is used to perform accompanying state inversion and risk source sensitivity analysis with the aforementioned maximum tension at the top of the tower as the objective function, so as to calculate the sensitivity of the objective function to environmental mechanical parameters at various points in the environmental mechanical characteristic field.

[0076] The optimization and decision support module is used to perform comprehensive assessments based on sensitivity to identify key risk sources that have a significant impact on the maximum tension at the top of the tower.

[0077] The data acquisition and preprocessing module is used to acquire the raw physical data required for building the simulation environment from external measurement equipment and perform standardization processing. This module receives and parses a set of discrete three-dimensional velocity data points measured by equipment such as an acoustic Doppler velocity profiler, where each data point contains geographic coordinates. and the corresponding water flow velocity vector .

[0078] This module is also used to receive and parse riverbed elevation datasets measured by equipment such as multibeam echo sounders. Based on the geometric features and location information of obstacles identified from the side-scan sonar images, structured terrain feature data is formed.

[0079] The data acquisition and preprocessing module performs operations such as noise reduction, outlier removal, and coordinate system registration on the received raw data to ensure data consistency and accuracy, providing standardized data input for subsequent modules.

[0080] The Environmental Mechanical Feature Field (EMCF) construction module transforms preprocessed discrete environmental data into a continuous, multi-layered three-dimensional data field. This module performs a pre-computation process designed to separate the static mechanical properties of the environment from subsequent dynamic simulations.

[0081] This module generates a continuous basic fluid velocity potential field by spatially interpolating discrete flow velocity data. ,in It is a spatial location vector.

[0082] This module, based on the fundamental fluid velocity potential field, further calculates and generates the vortex-induced energy injection rate field. For any point r within the field, its calculation follows the formula:

[0083] ;

[0084] ;

[0085] ;

[0086] in, Let Reynolds number be 1. For Strouhal's number, This is the water flow velocity vector at that point. The diameter of the ground wire, The kinematic viscosity of water, This is the natural vibration frequency of the conductor in water. It is a deterministic mapping function from Reynolds number and Strouhal number to energy injection rate, pre-calibrated through experiments or refined simulations.

[0087] This module also generates a two-dimensional stochastic anchored potential well field based on terrain and geomorphological data. The field consists of two components: the anchoring probability and the maximum static friction force.

[0088] ;

[0089] in, The conductor's position in the riverbed The probability of getting stuck. This represents the maximum restraining force that can be provided when a snag occurs at that point. The values ​​of these two components are quantified based on geometric and geological properties such as riverbed slope, curvature, and obstacle type.

[0090] The dynamics simulation engine module is used to simulate the complete dynamic process of a conductor falling into water from the moment of failure, given initial and boundary conditions. This module first discretizes the continuous conductor model into a flexible multibody system composed of particles and spring-damped elements. The state of each particle is determined by its position vector. and velocity vector describe.

[0091] During the simulation, this module solves the motion equations of each particle using numerical integration. At each time step, it interpolates the EMCF generated by the environmental mechanics feature field construction module to obtain environmental parameters such as flow velocity, energy injection rate, and anchoring risk at the location of each particle, and calculates external loads such as hydrodynamics and anchoring force accordingly, and then updates the motion state of the particle.

[0092] The accompanying state inversion and sensitivity analysis module is used to efficiently calculate the sensitivity of the final risk index to various influencing factors during the simulation process after completing a forward dynamic simulation. This module uses the maximum tension J at the top of the tower output from the forward simulation as the objective function.

[0093] This module constructs and solves its corresponding linearized adjoint equations based on the governing equations of forward dynamics. The solution process begins at the end of the simulation. Integrate in reverse to the initial time step The accompanying state vector is obtained. The time series.

[0094] Using the obtained adjoint state vector, this module calculates the gradient of the objective function J with respect to any physical parameter (such as anchoring force or hydrodynamic force at a specific location) along the simulation path. The calculation result is then used to generate a three-dimensional risk source sensitivity map. This map visually indicates the spatial regions that contribute the most to the final risk.

[0095] The optimization and decision support module is used to optimize the construction plan based on the sensitivity analysis results. This module receives user-defined controllable construction parameters, such as the initial release tension of the conductor and ground wire, and the tension control curves of the traction machines on both sides, denoted as a parameter vector. .

[0096] This module utilizes the gradient of the objective function with respect to construction parameters calculated by the adjoint state inversion and sensitivity analysis module. The parameter vector is iteratively adjusted using optimization algorithms such as gradient descent. The aim is to find the optimal construction scheme that minimizes the maximum tension J at the top of the tower.

[0097] The visualization and interactive interface module provides a human-computer interaction interface and graphically displays data, processes, and results. This module is responsible for rendering and displaying the two-dimensional and three-dimensional data fields generated by the environmental mechanical feature field construction module.

[0098] This module also dynamically and in three dimensions displays the conductor-to-water drop process calculated by the dynamics simulation engine module. After the simulation, this module will display the risk source sensitivity map generated by the adjoint state inversion and sensitivity analysis module. The data is overlaid with the riverbed topography to generate a comprehensive assessment report that includes key risk indicators and optimization recommendations.

[0099] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines, characterized in that... Includes the following steps: Obtain hydrodynamic data and riverbed topography data of the construction section, and construct an environmental mechanical characteristic field containing environmental mechanical parameters based on the data; In the aforementioned environmental mechanical characteristic field, a forward dynamic simulation of the conductor falling into the water is performed to obtain the maximum tension at the top of the tower as a risk indicator; Using the aforementioned maximum tension at the top of the tower as the objective function, an adjoint state inversion and risk source sensitivity analysis are performed to calculate the sensitivity of the objective function to environmental mechanical parameters at various points in the environmental mechanical characteristic field. A comprehensive assessment is conducted based on the aforementioned sensitivity to identify key risk sources that significantly affect the maximum tension at the top of the tower.

2. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 1, characterized in that, The constructed environmental mechanical characteristic field includes: Construct a basic fluid velocity potential field; Construct a vortex-induced energy injection rate field; Construct a stochastic anchored potential well field.

3. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 2, characterized in that, The construction of the vortex-induced effect energy injection rate field includes: Calculate the Reynolds number and Strouhal number at any position within the field based on the aforementioned basic fluid velocity potential field; The vortex-induced energy injection rate field is calculated using a pre-calibrated mapping function from Reynolds number and Strouhal number to energy injection rate.

4. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 2, characterized in that, The random anchoring potential well field consists of two components: the anchoring probability and the maximum static friction force. The anchoring probability is determined based on the local geometric characteristics of the riverbed, and the maximum static friction force is determined based on the geological properties of the riverbed.

5. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 1, characterized in that, In the forward dynamics simulation, the hydrodynamic force on the conductor is calculated using the Morison equation, and the effective drag coefficient in the Morison equation is corrected by an increment related to the accumulated vortex-induced energy. The accumulated vortex-induced energy is obtained by integrating the energy injection rate field of the vortex-induced effect along the conductor's trajectory.

6. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 1, characterized in that, The accompanying state inversion and risk source sensitivity analysis include: Based on the control equations of the aforementioned forward dynamics simulation, construct its corresponding adjoint equation set; Solve the adjoint equations by inverse integration from the end of the simulation to obtain the time series of the adjoint state vector.

7. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 1, characterized in that, The method further includes: Based on the solved adjoint state vector, a three-dimensional risk source sensitivity map is generated to quantify the contribution of risk sources.

8. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 7, characterized in that, The comprehensive assessment includes: The three-dimensional risk source sensitivity map is superimposed with the random anchored potential well field for analysis to identify the key risk sources.

9. The method for assessing the safety of conductors falling into water during the dismantling of cross-river power lines according to claim 1, characterized in that, The method further includes: Using the sensitivity as gradient information, the controllable construction parameters in the construction plan are iteratively adjusted through optimization algorithms to minimize the maximum tension at the top of the tower.

10. A safety assessment system for conductor and ground wire falling into water during the dismantling of a cross-river power line, used in accordance with any one of claims 1-9, characterized in that, include: The environmental mechanics feature field construction module is used to acquire hydrodynamic data and riverbed topography data of the construction section, and construct an environmental mechanics feature field containing environmental mechanics parameters based on the data. The dynamics simulation engine module is used to perform forward dynamics simulation of the conductor falling into the water process in the environmental mechanical characteristic field to obtain the maximum tension at the top of the tower as a risk indicator. The accompanying state inversion and sensitivity analysis module is used to perform accompanying state inversion and risk source sensitivity analysis with the aforementioned maximum tension at the top of the tower as the objective function, so as to calculate the sensitivity of the objective function to the environmental mechanical parameters at various points in the environmental mechanical characteristic field. The optimization and decision support module is used to perform a comprehensive evaluation based on the sensitivity to identify key risk sources that have a significant impact on the maximum tension at the top of the tower.

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