Stability analysis method and device for highway assembly type box culvert

Abstract

The invention provides a stability analysis method and device for a highway assembly type box culvert, and relates to the technical field of box culvert stability analysis. Firstly, the service life, geometric parameters and material characteristics of the box culvert are collected, sampling points are determined, environmental data are collected so as to analyze the influence of the environment on the material characteristics, time-dependent correction factors are introduced, and the corrected material characteristics are obtained. Then, establishing a finite element model, inputting different loads, obtaining stress and displacement data of the sampling points, evaluating the stability of the sampling points, and marking points with poor stability; generating a stability index of the sampling point at the current moment by combining the stability of the sampling point and the environmental data, and marking the sampling point with poor stability; comprehensively analyzing the stability index of each sampling point to obtain the stability index of the box culvert, and comparing the stability index of the box culvert with a preset threshold to determine the stable state of the box culvert. The implementation of the method can effectively improve the safety monitoring capability of the highway box culvert.

Description

Technical Field

[0001] The present invention relates to the technical field of culvert stability analysis, and particularly to a method and device for analyzing the stability of highway prefabricated culverts. Background Art

[0002] As an important part of modern transportation infrastructure, highway prefabricated culverts are widely used in urban and rural road construction, mainly for various functions such as drainage, traffic passage, and underground pipeline laying. Their design and construction technologies have evolved through multiple stages, gradually forming a more reasonable, economical, and environmentally friendly solution. The advantage of highway prefabricated culverts lies in their efficient construction method. Compared with traditional cast-in-place concrete structures, prefabricated culverts are composed of precast components and can be standardized produced in factories, reducing on-site construction time and labor costs. This method not only improves construction efficiency but also reduces the impact on the on-site environment, meeting the requirements of sustainable development. With the increase in traffic flow and the change of environmental conditions, as an important transportation infrastructure, the safety and stability of highway culverts have attracted increasing attention.

[0003] Traditional culvert monitoring methods often rely on regular inspections and empirical judgments, making it difficult to reflect their actual usage status in real time and posing a risk of overlooking potential hidden dangers. In addition, the influence of environmental factors such as temperature, humidity, and soil conditions on material properties has not been fully considered, resulting in the inability to accurately evaluate the long-term stability of culverts in actual use. These problems urgently require a systematic and dynamic analysis method to improve the safety monitoring and evaluation capabilities of culverts.

[0004] The above information disclosed in the background art section is only used to enhance the understanding of the background of the present disclosure, and thus it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and device for analyzing the stability of highway prefabricated culverts to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: A method for analyzing the stability of a highway prefabricated culvert, the specific steps including: Step 1: Collect the service life, geometric parameters, and material properties of the culvert, determine the sampling points of the culvert, collect the environmental data at the sampling points to analyze the influence of the environmental data on the material properties of the culvert, and introduce a time-dependent correction factor according to the service life of the culvert to obtain the corrected material properties of the culvert; Step 2: Based on the geometric parameters of the culvert and the corrected material properties, establish a finite element model of the culvert, conduct a simulated load test on the finite element model, input the simulated load into the finite element model, and obtain the maximum simulated load; Step 3: Obtain the actual loads of the culvert at the first N moments, input the actual loads of the culvert at the first N moments into the finite element model, obtain the stress and displacement at the sampling points of the culvert, analyze the stability of each sampling point of the culvert at the first N moments, and mark the sampling points with poor stability; Step 4: Combine the stability of each sampling point of the culvert at the first N moments with the environmental data and soil compactness at the sampling points of the culvert at the current moment to generate the stability index of the culvert at the current moment, and determine whether the culvert is stable at the current moment by analyzing the stability index of the culvert.

[0007] Further, establishing the finite element model of the culvert specifically includes: The geometric parameters of the culvert include the length, width, and height of the culvert, and the material properties include elastic modulus, compressive strength, and density. Set the middle position at the top of the culvert, the corners, and the middle position of the joints as the sampling points of the culvert. The environmental data includes environmental temperature and environmental humidity. Arrange temperature sensors and humidity sensors at the sampling points to collect temperature and humidity data at the sampling points, analyze the influence of the temperature and humidity data at each sampling point on the elastic modulus in the material properties of the culvert, and obtain the elastic model after being affected by the temperature and humidity data. The calculation formula is: ; Where is the elastic modulus of the i-th sampling point after being affected by the temperature and humidity data, is the initial elastic modulus, is the environmental temperature of the i-th sampling point, is the environmental humidity of the i-th sampling point, are the temperature and humidity reference values respectively, and a and b are the corresponding weight coefficients; According to the service life of the culvert, obtain the time-dependent correction factor. The calculation formula is: ; Where is the time-dependent correction factor, is the empirical coefficient in the elastic modulus, is the service life, is the reference time; Introduce the time-dependent correction factor to correct the elastic modulus after being affected by the environmental data. The calculation formula is: ; Where is the elastic modulus of the i-th sampling point after being corrected by environmental data and service life; Introduce a time-dependent correction factor to correct the initial compressive strength of the culvert. The calculation formula is: ; where, is the compressive strength of the culvert after being corrected by the time-dependent correction factor, is the initial compressive strength, is the empirical coefficient in the compressive strength.

[0008] Furthermore, obtaining the stress and displacement data of the finite element model under various loads specifically includes: Using finite element analysis software, establish a geometric model of the three-dimensional culvert, input the length, width and height of the culvert, input the compressive strength and density of the culvert, and input the elastic modulus of each sampling point of the culvert. Select the eight-node brick element to mesh the finite element model of the culvert. Set the displacements of the nodes at the bottom of the culvert in the X direction, Y direction and Z direction to 0. Select the elastic soil model, take the surface where the bottom of the culvert contacts the soil as the contact surface, apply a displacement constraint of 0 to the side surface of the finite element model of the culvert, and set the vertical displacement to allow up and down movement. When the model is applied with a vertical displacement, apply the corresponding soil reaction force at the same time; Then apply a simulated load to the top contact surface of the finite element model of the culvert. Select the static analysis solver. When applying the load, gradually increase the applied load from small to large, and repeat the finite element analysis until the maximum stress of the model reaches the compressive strength of the culvert after being corrected by the time-dependent correction factor. At this time, it is regarded as having reached the maximum simulated load that the culvert can bear. Stop applying the load and record the maximum simulated load that the culvert can bear.

[0009] Furthermore, analyzing the stress and displacement at the sampling points of the culvert specifically includes: Record the vehicle type and vehicle number passing through the culvert at each moment, calculate the actual load of the culvert at each moment, input the actual load of the culvert at the previous N moments into the finite element model, output the stress and displacement data of the sampling points of the culvert through the finite element model, analyze the safety factor of the culvert at each moment, and calculate the stress safety factor formula as: ; where, is the stress safety factor of the i-th sampling point at time t, is the compressive strength of the culvert after being corrected by the time-dependent correction factor, is the stress of the i-th sampling point at time t output by the finite element model; The formula for calculating the displacement safety factor is: ; Among them, is the displacement safety factor of the i-th sampling point at time t, is the displacement of the i-th sampling point at time t output by the finite element model, is the maximum allowable displacement set by the design specification.

[0010] Furthermore, specifically marking the sampling points with poor stability includes: Comprehensively analyzing the comprehensive safety factor of the i-th sampling point at time t according to the stress safety factor and the displacement safety factor, and the calculation formula is: ; Among them, is the comprehensive safety factor of the i-th sampling point at time t, are the weight coefficients of the corresponding items respectively, , and ; Calculate the mean and standard deviation of the comprehensive safety factor of each sampling point in the first N moments of the culvert. Based on the mean and standard deviation of the comprehensive safety factor of each sampling point, obtain the volatility of each sampling point within the first N moments, and the calculation formula is: ; Among them, is the volatility of the i-th sampling point, is the standard deviation of the comprehensive safety factor of the i-th sampling point, is the mean of the comprehensive safety factor of the i-th sampling point; Calculate the mean value of the volatility of all sampling points of the culvert, compare the volatility of each sampling point with the mean value of the volatility. If the number of sampling points with volatility higher than the mean value of the volatility is less than half of the total number of sampling points, no marking is performed on the sampling points. If the number of sampling points with volatility higher than the mean value of the volatility is higher than or equal to half of the total number of sampling points, the sampling points with volatility higher than the mean value of the volatility are marked as having poor stability.

[0011] Furthermore, based on the soil density, temperature and humidity data, generate an environmental impact index, and the calculation formula is: ; Among them, is the environmental impact index of the i-th sampling point, is the environmental temperature of the i-th sampling point, is the humidity calculation function of the i-th sampling point, is the soil density of the i-th sampling point, , , are the weight coefficients of the corresponding items respectively, , and ; The humidity calculation function is specifically as follows: ; Among them, is the ambient humidity at the i-th sampling point, is the maximum value within the appropriate humidity range, is the minimum value within the appropriate humidity range.

[0012] Furthermore, generating the stability index of the culvert at the current moment specifically includes: Generating the stability index of each sampling point of the culvert according to the comprehensive safety factor and environmental impact index of each sampling point of the culvert. The calculation formula is: ; Among them, is the stability index of the i-th sampling point at the current moment, is the comprehensive safety factor of the i-th sampling point at the current moment, is the control factor of the environmental impact index, is the threshold parameter of the environmental impact index, ; If there is no sampling point in the culvert marked as having poor stability, calculate the mean value of the stability indices of all sampling points in the culvert as the stability index of the culvert. If there is a sampling point in the culvert marked as having poor stability, the calculation formula for the stability index of the culvert is: ; Among them, SI is the stability index of the culvert at the current moment, n is the total number of sampling points not marked as having poor stability, is the stability index of the sampling point not marked as having poor stability at the current moment, x is the index of the sampling point not marked as having poor stability, and , m is the total number of sampling points marked as having poor stability, is the stability index of the sampling point marked as having poor stability at the current moment, y is the index of the sampling point marked as having poor stability, and , are the weight coefficients of the corresponding items respectively, ; Judge the load borne by the culvert at the current moment. If the load borne by the culvert at the current moment has reached the maximum simulated load that the culvert can bear, directly mark that the stability of the culvert at the current moment is poor. If the culvert at the current moment has not reached the maximum simulated load that the culvert can bear, then judge the stability index of the culvert, compare the stability index of the culvert with the preset stability threshold. If the stability index of the culvert is higher than the preset stability threshold, it indicates that the culvert is in a good stability state at the current moment. If the stability index of the culvert is lower than the preset stability threshold, it indicates that the culvert is in a poor stability state at the current moment.

[0013] The present invention further provides a stability analysis device for a highway prefabricated culvert. The stability analysis device for a highway prefabricated culvert is used to implement the above-mentioned stability analysis method for a highway prefabricated culvert, and includes: A data acquisition and correction module, which is used to collect the service life, geometric parameters and material properties of the culvert, determine the sampling points of the culvert, collect the environmental data at the sampling points, analyze the influence of the environmental data on the material properties of the culvert, and introduce a time-dependent correction factor according to the service life of the culvert to obtain the corrected material properties of the culvert; A finite element model establishment module, which is used to establish a finite element model of the culvert based on the geometric parameters and corrected material properties of the culvert, conduct a simulated load test on the finite element model, input the simulated load into the finite element model, and obtain the maximum simulated load; An actual load analysis module, which is used to obtain the actual loads of the culvert at the previous N moments, input the actual loads of the culvert at the previous N moments into the finite element model, obtain the stress and displacement at the sampling points of the culvert, analyze the stability of each sampling point of the culvert at the previous N moments, and mark the sampling points with poor stability; A stability evaluation module, which is used to generate the stability index of the culvert at the current moment by combining the stability of each sampling point of the culvert at the previous N moments and the environmental data and soil compactness at the sampling points of the culvert at the current moment, and determine whether the culvert is stable at the current moment by analyzing the stability index of the culvert.

[0014] In the above technical solution, the technical effects and advantages provided by the present invention are: By comprehensively considering the geometric parameters, material properties and environmental impacts of the culvert, the present invention significantly improves the safety assessment and monitoring capabilities of the culvert structure. Using the finite element model for dynamic stress and displacement analysis can capture the performance of the culvert under different working conditions in real time, identify potential risk points, and thus achieve active early warning and maintenance. This method not only provides a scientific basis for traffic management, but also can extend the service life of the culvert and avoid safety accidents caused by structural instability.

[0015] In addition, this method introduces a time-dependent correction factor to analyze the influence of the service life of the culvert on material properties. By real-time monitoring of environmental changes, the accuracy and reliability of the analysis results are ensured. Compared with traditional static evaluation methods, the generation method of the dynamic stability index enables engineers to timely evaluate the health status of the culvert, thereby more effectively formulating maintenance and reinforcement plans. This comprehensive and systematic analysis method fully reflects the development trend of intelligence and dataization in modern engineering management, providing a strong guarantee for the safe operation of highway traffic infrastructure. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the overall method flow of the present invention; Figure 2 It is a schematic diagram of the device structure of the present invention. Detailed Embodiment

[0017] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments.

[0018] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meaning understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative position relationships, and when the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0019] Embodiment: Please refer to Figure 1 , the present invention provides a technical solution: A method for analyzing the stability of a highway prefabricated culvert, the specific steps include: Step 1: Collect the service life, geometric parameters and material properties of the culvert, determine the sampling points of the culvert, collect the environmental data at the sampling points to analyze the influence of the environmental data on the material properties of the culvert, and introduce a time-dependent correction factor according to the service life of the culvert to obtain the corrected material properties of the culvert; In this embodiment, specifically establishing the finite element model of the culvert includes: The geometric parameters of the box culvert include the length, width, and height of the box culvert, and the material properties include the elastic modulus, compressive strength, and density. The middle position at the top of the box culvert, the corners, and the middle position of the joints are set as the sampling points of the box culvert. The environmental data includes the environmental temperature and environmental humidity; The corners of the box culvert are often areas of stress concentration. Due to the geometric changes of the structure and the action of forces, relatively large local stresses may occur at the corner positions. The joint is the place where two or more parts are connected, and stress concentration usually occurs due to material properties, construction techniques, or external loads. Therefore, setting sampling points at the joints can monitor the integrity and strength of the joints to ensure that no cracks or other damages occur; the middle position at the top of the box culvert is usually an area where the forces are evenly distributed, which can reflect the performance of the overall structure. Sampling at these positions can effectively monitor the deformation and fatigue of the material.

[0020] Temperature sensors and humidity sensors are arranged at the sampling points to collect the temperature and humidity data at the sampling points, analyze the influence of the temperature and humidity data of each sampling point on the elastic modulus in the material properties of the box culvert, and obtain the elastic model after being affected by the temperature and humidity data. The calculation formula is: ; Among them, is the elastic modulus of the i-th sampling point after being affected by the temperature and humidity data, is the initial elastic modulus, is the environmental temperature of the i-th sampling point, is the environmental humidity of the i-th sampling point, are the temperature and humidity reference values respectively. The temperature reference value can be set to 25 °C, and the humidity reference value can be set to 60%. a and b are the corresponding weight coefficients respectively, b < a, and the weight coefficients can be obtained by fitting according to the actual data. The specific method can adopt the least squares method.

[0021] The temperature reference value is usually set as the normal temperature, which represents the state of the material under standard environmental conditions. Selecting this temperature as the reference helps to make comparisons in practical applications and is convenient for evaluating the changes in material properties under different environmental temperatures, especially under climate change or extreme temperature conditions, to evaluate its influence on the elastic modulus of the box culvert material. The humidity reference value is usually considered as a relatively comfortable environmental humidity and is also the standard humidity for testing many building materials under experimental conditions. Selecting 60% humidity as the reference can help analyze the influence of moisture on material properties. In environments with higher or lower humidity, the change in the moisture content of the material will affect its mechanical properties and durability. Therefore, using this reference value can provide a recognized starting point for evaluating the influence of humidity on the elastic modulus.

[0022] Temperature and humidity are important environmental factors that affect the mechanical properties of building materials. The elastic modulus of a material reflects its ability to resist deformation. Under different temperature and humidity conditions, the internal structure and molecular motion state of the material will change, thus affecting its mechanical properties. For example, an increase in temperature usually intensifies the molecular activity of the material, which may lead to a decrease in the elastic modulus; while an increase in humidity may cause the material to absorb water and expand, further affecting its mechanical properties. By correcting the elastic modulus, the behavior of the material in the actual use environment can be more accurately reflected, thereby improving the accuracy and reliability of the model.

[0023] The elastic model affected by temperature and humidity is used as the dependent variable, which reflects the elastic characteristics of the material under specific environmental conditions, namely temperature T and humidity H. The elastic modulus is an important parameter that describes the ability of a material to resist elastic deformation and determines the degree of deformation of the material under external force. By obtaining the elastic modulus affected by temperature and humidity, the performance of culvert materials under different environmental conditions can be more accurately predicted, providing a scientific basis for structural design and safety assessment. This correction makes the model more practical and better able to adapt to actual working conditions.

[0024] When the environmental temperature T is higher than the reference temperature, is positive, and the elastic modulus (T,H) will decrease with the increase in temperature, which shows that an increase in temperature usually reduces the elastic modulus of the material; for humidity H, if H is higher than the reference humidity, then is positive, and the elastic modulus (T,H) may also decrease, otherwise it will increase.

[0025] Temperature usually has a significant impact on the mechanical properties of materials. As the temperature increases, the molecular motion of the material increases, often leading to a decrease in the elastic modulus. In many engineering materials, the impact of temperature change on performance is relatively strong. Therefore, it is reasonable to set the weight coefficient a to be relatively large and a > 1 to ensure that the corrected elastic modulus does not exceed the initial value. The impact of humidity on materials is usually relatively small. Although an increase in humidity may cause some materials to absorb water and expand or soften, generally its impact degree is less than that of temperature change. Therefore, it is in line with the actual situation to set the weight coefficient b to be relatively small and b < a.

[0026] According to the service life of the culvert, obtain the time-dependent correction factor, and the calculation formula is: ; where, is the time-dependent correction factor, is the empirical coefficient in the elastic modulus, which can be obtained by fitting with actual data, is the service life, is the reference time; f represents the degree of attenuation or change in the material properties of the box culvert over its service life. It is an adjustment factor used to correct the mechanical properties of the material (such as elastic modulus, compressive strength, etc.) in order to more accurately reflect the performance changes caused by the passage of time. By introducing the time-dependent correction factor f, the structural performance and safety of the box culvert during long-term use can be more accurately evaluated. The calculation of this correction factor can help engineers consider the impact of material aging and service environment on performance during the design and maintenance processes, improving the safety and reliability of the structure.

[0027] The independent variable l is directly related to the dependent variable f. Specifically, the larger the service life l, the longer the time the material has experienced under the environmental action, and the greater the possibility of performance attenuation. The reference time is a benchmark used to judge the state of the material. Compared with this benchmark, the change in the service life will directly affect the correction factor. Here, the reference time can be set to 1 year. The logarithmic function in the formula indicates that when l increases, the value of increases, resulting in the value of increasing, thus reducing f. This shows that as the service life increases, the time-dependent correction factor f will decrease, reflecting the trend of material performance decay over time. In the formula, is positively correlated with l. When l increases and exceeds , is positive, so is also positive. Since f is obtained by subtracting a positive value from 1, the relationship between f and l is inversely correlated. When the service life l increases, the correction factor f decreases, meaning that the performance of the material decreases. This inverse correlation reasonably reflects the negative impact of time on material performance in practical applications. The value of the empirical coefficient can be between [0.1, 1], and it can be increased accordingly with the increase in the service life of the box culvert and the deterioration of the environmental conditions, increasing the value.

[0028] The elastic modulus after correcting the environmental data impact by introducing the time-dependent correction factor is calculated by the formula: ; where, is the elastic modulus of the i-th sampling point after correcting for environmental data and service life.

[0029] represents the actual elastic modulus of the box culvert at a specific temperature T, humidity H, and service life l, which reflects the mechanical property changes of the material under long-term use and environmental influences. By introducing a time-dependent correction factor f, this formula can more accurately calculate the elastic modulus of the box culvert under actual use conditions. There is a direct relationship between these independent variables T, H, l and the dependent variable and T and H can affect the physical properties of the material, while the service life affects the aging process of the material. The elastic modulus is a measure of the material's ability to resist elastic deformation, and all these factors will have a significant impact on the elastic modulus.

[0030] In the formula, although is the basic value of the elastic modulus, but after introducing the correction factor , 's calculation result will be affected by f. The value of f decreases as l increases. When f increases, increases, and when f decreases, decreases, showing a positive correlation. And the influence of the environmental impact on the material properties of the box culvert itself decreases, that is, increases, then also increases, and the two also show a positive correlation.

[0031] Introduce a time-dependent correction factor to correct the initial compressive strength of the box culvert. The calculation formula is: ; where, is the compressive strength of the box culvert after being corrected by the time-dependent correction factor, is the initial compressive strength, is the empirical coefficient in the compressive strength, which can be obtained by fitting with actual data.

[0032] C represents the actual compressive strength of the box culvert considering the influence of time factors at the service life l. It reflects the possible strength changes of the material during long-term use. The box culvert is usually composed of materials such as concrete and steel. These materials may experience aging, fatigue, and chemical reactions (such as the hydration reaction of cement, alkali-aggregate reaction, etc.) during long-term use, resulting in a decrease in strength. During use, the loads borne by the box culvert (such as traffic loads, soil loads, etc.) will have a long-term impact on its structure. Over time, the accumulated loads may cause changes in the microstructure of the material, thereby affecting the compressive strength. During use, cracks, settlements, or deformations may occur, and these structural defects will also affect the compressive strength of the box culvert, further affecting its bearing capacity and stability.

[0033] Step 2: Based on the geometric parameters of the box culvert and the corrected material properties, establish a finite element model of the box culvert, conduct a simulated load test on the finite element model, input the simulated load into the finite element model, and obtain the maximum simulated load; In this embodiment, obtaining the stress and displacement data of the finite element model under various loads specifically includes: Using finite element analysis software such as ANSYS, Abaqus, COMSOL Multiphysics, etc., establish a geometric model of the three-dimensional box culvert, input the length, width, and height of the box culvert. For example, create a box culvert with a length of 10 meters, a width of 4 meters, and a height of 3 meters, input the compressive strength and density of the box culvert, and input the elastic modulus of each sampling point of the box culvert. Select the eight-node brick element to mesh the finite element model of the box culvert. Set the displacements of the nodes at the bottom of the box culvert in the X, Y, and Z directions to 0. Select the elastic soil model, take the surface in contact with the soil at the bottom of the box culvert as the contact surface, define the friction coefficient as 0.3, apply a displacement constraint of 0 to the side surface of the finite element model of the box culvert, and set the vertical displacement to allow up and down movement. When the model is applied with a vertical displacement, apply the corresponding soil reaction force at the same time; Then apply a simulated load to the top contact surface of the finite element model of the box culvert. Select the static analysis solver. When applying the load, gradually increase the applied load from small to large, and repeat the finite element analysis until the maximum stress of the model reaches the compressive strength of the box culvert after being corrected by the time-dependent correction factor. At this time, it is considered that the maximum simulated load that the box culvert can bear has been reached. Stop applying the load and record the maximum simulated load that the box culvert can bear.

[0034] By using finite element analysis software, an accurate three-dimensional geometric model of the box culvert can be created to ensure that the model can truly reflect the geometric shape and size of the actual structure (such as length, width, and height). This method can handle complex boundary conditions and material nonlinearities, provide a detailed analysis of the response of the box culvert under different loads, and ensure that the constructed model is representative and reliable in actual engineering. Setting the nodes at the bottom of the box culvert to be fixed in three directions can effectively simulate the supporting effect of the soil and avoid unreasonable displacements of the model during calculation. Selecting the elastic soil model and defining the friction coefficient can more realistically reflect the interaction between the soil and the box culvert and enhance the realism of the analysis. Selecting the static analysis method is reasonable for the common traffic load application method and can truly reflect the stress and deformation state of the box culvert under normal use. The initial elastic modulus, compressive strength, and density data of the box culvert can all be obtained from the concrete type in the production report of the box culvert, and then the elastic modulus, compressive strength, and density data corresponding to the concrete type can be obtained by consulting relevant literature, engineering reports, and material property databases.

[0035] Step 3: Obtain the actual loads of the culvert at the previous N moments, input the actual loads of the culvert at the previous N moments into the finite element model, obtain the stress and displacement at the sampling points of the culvert, analyze the stability of each sampling point of the culvert at the previous N moments, and mark the sampling points with poor stability; In this embodiment, analyzing the stress and displacement at the sampling points of the culvert specifically includes: Record the vehicle types and the number of vehicles passing through the culvert at each moment, calculate the actual load of the culvert at each moment, input the actual loads of the culvert at the previous N moments into the finite element model, output the stress and displacement data of the sampling points of the culvert through the finite element model, analyze the safety factor of the culvert at each moment, and the formula for calculating the stress safety factor is: ; Wherein, is the stress safety factor of the i-th sampling point at time t, is the compressive strength of the culvert after being corrected by the time-dependent correction factor, is the stress of the i-th sampling point at time t output by the finite element model, t is the index of the previous N moments, and ; The actual load can obtain the number of different types of vehicles passing through through the traffic flow data released by relevant departments or research institutions, and then refer to relevant design standards to obtain the average load of each vehicle type (for example, the average weight of a car may be 1.5 tons, a truck is 10 tons, and a bus is 8 tons). Based on the traffic flow statistics data, the calculation can be carried out: , and the actual load data can be obtained through this formula.

[0036] The stress safety factor reflects the ratio between the actual bearing capacity of the sampling point and the actual stress it bears. It represents the safety margin of the material under the current load. The larger the value, the safer the material and the greater the load it can bear; on the contrary, the smaller the value, the closer the material is to the failure state. By calculating the stress safety factor, the safety condition of the culvert can be effectively identified, especially the sampling points that are unstable or may be damaged. C is the compressive strength of the corrected culvert, is the stress calculated by the finite element model. When the compressive strength remains unchanged, the larger the stress value of the sampling point, the lower the stress safety factor of the sampling point, indicating that the load borne by the material is approaching its ultimate bearing capacity. On the contrary, if the stress of the sampling point becomes smaller, the corresponding stress safety factor will increase, and the two show an inverse correlation.

[0037] The formula for calculating the displacement safety factor is: ; Wherein, is the displacement safety factor of the i-th sampling point at time t, is the displacement of the i-th sampling point at time t output by the finite element model, is the maximum allowable displacement set by the design specification.

[0038] The displacement safety factor reflects the ratio between the maximum allowable displacement set by the design specification for this sampling point and the displacement calculated under actual working conditions. It represents the relative relationship between the displacement of the structure under actual loads and the allowable displacement. The maximum allowable displacement can refer to the set value based on the design specification in the installation working plan of this culvert. By calculating the displacement safety factor, the deformation degree of the structure under stress can be effectively evaluated to ensure that the displacement of the structure during normal use does not exceed the design allowable displacement range. This has an important impact on the durability and safety of the structure, helping engineers to timely discover potential problems and carry out necessary maintenance and reinforcement.

[0039] The maximum allowable displacement is a fixed value. As the displacement of the sampling point increases, the displacement safety factor of this sampling point will decrease, indicating that the safety of the structure decreases and may approach or exceed the maximum allowable displacement; conversely, as the displacement of the sampling point decreases or does not exist, the displacement safety factor of this sampling point will increase, indicating that the safety margin of the structure under the current load increases, and the two show an inverse correlation.

[0040] In this embodiment, specifically marking the sampling points with poor stability includes: Comprehensively analyzing the comprehensive safety factor of the i-th sampling point at time t according to the stress safety factor and the displacement safety factor. The calculation formula is: ; where, is the comprehensive safety factor of the i-th sampling point at time t, are the weight coefficients of the corresponding items respectively, and ; The comprehensive safety factor is a comprehensive evaluation of the safety status of this sampling point at the current time, combining the influences of the stress safety factor and the displacement safety factor. Through the method of weighted average, the safety of the structure in terms of both stress and displacement is integrated. This formula can provide a comprehensive evaluation index for different factors, enabling engineers to comprehensively understand the safety of the culvert.

[0041] The stress safety factor and the displacement safety factor respectively reflect the safety of the material in terms of bearing capacity and deformation ability. When the stress safety factor increases, the comprehensive safety factor will increase accordingly, indicating that the structure is safer in terms of bearing capacity. When the displacement safety factor increases, the comprehensive safety factor will also increase, indicating that the structure is safer in terms of deformation. Conversely, if the stress safety factor and the displacement safety factor decrease, both will lead to a decrease in the comprehensive safety factor.

[0042] In many engineering applications, the load-bearing capacity of materials (represented by the stress safety factor) is often considered more important than displacement (represented by the displacement safety factor). The reason is that material failure is usually caused by overloading, at which time the stress of the material may reach its limit, while excessive displacement may lead to a reduction in the service performance of the structure, but does not necessarily cause immediate failure. Therefore, the safety of the load-bearing capacity is usually given a higher priority in the overall structural safety.

[0043] Calculate the mean and standard deviation of the comprehensive safety factor for each sampling point in the first N moments of the culvert box. Based on the mean and standard deviation of the comprehensive safety factor for each sampling point, obtain the volatility of each sampling point within the first N moments. The calculation formula is: ; where, is the volatility of the i-th sampling point, is the standard deviation of the comprehensive safety factor of the i-th sampling point, is the mean of the comprehensive safety factor of the i-th sampling point; Volatility is usually used to measure the degree of fluctuation of a data set, indicating the dispersion of data points relative to their mean. In the fields of engineering and finance, volatility is often used as an indicator to measure risk and uncertainty. In this formula, volatility is defined by the ratio of the standard deviation to the mean, which can effectively reflect the fluctuation characteristics of the safety factor of each sampling point within the first N moments. Here, the first N moments refer to the previous time period of the current moment.

[0044] Calculate the mean volatility of all sampling points of the culvert box, and compare the volatility of each sampling point with the mean volatility. If the number of sampling points with volatility higher than the mean volatility is less than half of the total number of sampling points, the sampling points are not marked. If the number of sampling points with volatility higher than the mean volatility is greater than or equal to half of the total number of sampling points, the sampling points with volatility higher than the mean volatility are marked as having poor stability. The standard deviation is an important indicator of the degree of dispersion of a data set, reflecting the variation range of the comprehensive safety factor over N time instants. The larger the standard deviation, the more obvious the fluctuation of the comprehensive safety factor of the sampling point at different time points, which may indicate greater uncertainty or potential risks of the structure. The mean is the central value of the data set, representing the average level of the comprehensive safety factor. In this formula, through the ratio of the standard deviation to the mean, the volatility not only reflects the degree of dispersion of the comprehensive safety factor of the sampling point, but also takes into account its relative level. This means that even if the standard deviation of a sampling point is large, if its mean is also high, the volatility may still be low, indicating that the overall safety of this point is still high. Therefore, using the ratio of the standard deviation to the mean can more comprehensively evaluate the fluctuation characteristics of the sampling point. And since volatility is the ratio of the standard deviation to the mean, it is a dimensionless value, facilitating comparison between different sampling points, and volatility can provide relative change information.

[0045] Step 4: Combine the stability of each sampling point of the culvert box at the previous N time instants with the environmental data and soil compactness at the sampling point of the culvert box at the current time instant to generate the stability index of the culvert box at the current time instant, and determine whether the culvert box is stable at the current time instant by analyzing the stability index of the culvert box; In this embodiment, based on the soil compactness, temperature, and humidity data, an environmental impact index is generated, and the calculation formula is: ; Wherein, is the environmental impact index of the i-th sampling point, is the environmental temperature of the i-th sampling point, is the humidity calculation function of the i-th sampling point, is the soil compactness of the i-th sampling point, , , are the weight coefficients of the corresponding items respectively, , and ; The humidity calculation function is specifically: ; Wherein, is the environmental humidity of the i-th sampling point, is the maximum value within the appropriate humidity range, is the minimum value within the appropriate humidity range.

[0046] The compactness, temperature, and humidity of the soil change over time, and these changes directly affect the structural safety of the culvert. For example, an increase in soil humidity may lead to a decrease in the bearing capacity of the soil, thereby affecting the stability of the culvert. Combining real-time environmental data with the internal state of the culvert can also more comprehensively evaluate potential risk factors, thus better assisting in judging the stability of the culvert. The compactness of the soil at the location of the culvert can be measured on-site by the sand replacement method or the core cutter method, or the compactness of the soil can be directly obtained by placing a nuclear density instrument at the sampling point.

[0047] The environmental impact index represents the comprehensive impact degree of environmental factors (temperature, humidity, soil compactness) on the stability of the culvert. It quantifies the possible impact of the environment on the sampling point by comparing the deviation between the current environmental conditions and the reference value. This index can help engineers evaluate the stability of the culvert under different environmental conditions and provide early warning signals. Of course, it is specifically applied to the subsequent comprehensive consideration of the stability of the culvert. When the temperature deviates from the reference value, the environmental impact index will increase, indicating that the impact of the environment on the culvert has increased. This impact may lead to a decrease in the bearing capacity of the culvert or structural deformation, increasing the risk of instability. The change in temperature causes thermal stress inside the structure. If the temperature changes too quickly or by too large an amplitude, it may lead to cracks or other structural damages, thereby affecting the stability of the culvert. Humidity directly affects the physical properties of the soil, such as pore water pressure and the effective stress of the soil. When the humidity increases, the soil may become more saturated, resulting in a decrease in the bearing capacity, thereby affecting the stability of the culvert. A high-humidity environment also accelerates the corrosion of materials (especially steel), reducing their strength and durability. When the humidity is low, there may be a lack of water, and the soil may undergo shrinkage and form cracks, which will also affect the supporting capacity of the culvert. Therefore, within an appropriate range of humidity data, the culvert is more stable. The compactness of the soil is an important factor determining its bearing capacity. Dense soil can provide higher support force. Conversely, loose soil will reduce the stability of the culvert and have a negative impact on the bearing capacity of the load-bearing structure. Insufficient soil compactness may lead to settlement or uneven deformation, which will directly affect the overall stability and service performance of the culvert. When the temperature deviates from the reference value, the humidity exceeds the appropriate range, and the soil compactness is smaller, the environmental impact index will increase, indicating that the impact of the environment on the culvert has increased. This impact may lead to a decrease in the bearing capacity of the culvert or structural deformation, increasing the risk of instability. Therefore, considering these three indicators comprehensively helps to comprehensively evaluate the impact of the environment on the stability of the culvert.

[0048] The environmental impact index is positively correlated with the differences between the temperature and the reference value respectively. As the value of the temperature independent variable gets closer to the reference value, it indicates that the environment where the culvert is located is more conducive to the stability of the culvert. Therefore, the smaller the difference, the smaller the environmental impact index, which indirectly reflects that the stability of the culvert is better. On the contrary, the larger the difference between the temperature independent variable and the reference value, the larger the environmental impact index, which indirectly reflects that the stability of the culvert is poorer. When the humidity is within the appropriate range, its value is set to 0, and as the humidity deviates more from the appropriate range, its value becomes larger, and the environmental impact index also becomes larger. In addition, appropriate humidity can keep the soil in proper plasticity and cohesion, thus enhancing stability. Higher soil compaction means closer arrangement between soil particles, which can provide higher bearing capacity. This is very important for supporting structures (such as culverts), and can reduce the risk of settlement and deformation. Higher soil compaction means closer arrangement between soil particles, which can provide higher bearing capacity. This is very important for supporting structures (such as culverts), and can reduce the risk of settlement and deformation. Therefore, usually, the higher the soil compaction, the more stable the culvert, and the two also show a positive correlation.

[0049] Soil compaction is one of the most crucial factors affecting the stability of culverts. The soil bearing capacity, settlement resistance and overall stability largely depend on the degree of soil compaction. Insufficient compaction may lead to structural settlement or displacement, so it is reasonable to assign a higher weight in the environmental impact index. Temperature has a significant impact on material properties and structural stress states. Although temperature changes will cause some internal stresses, its direct impact on the stability of culverts is usually less than that of soil compaction. For example, temperature changes may cause materials to expand or contract, but its impact is usually secondary compared with the changes brought by soil compaction, so it is appropriate to assign a medium weight. Humidity mainly affects the moisture state of the soil and the corrosiveness of materials. Although humidity may cause structural problems in some cases (such as the decrease in bearing capacity after soil saturation), its impact on the overall stability is generally considered to be the smallest. Therefore, it is reasonable to assign it the lowest weight.

[0050] In this embodiment, generating the stability index of the culvert at the current moment specifically includes: Generating the stability index of each sampling point of the culvert according to the comprehensive safety factor and the environmental impact index of each sampling point of the culvert. The calculation formula is: ; Wherein, is the stability index of the i-th sampling point at the current moment, is the comprehensive safety factor of the i-th sampling point at the current moment, is the control factor of the environmental impact index, is the threshold parameter of the environmental impact index, ; The denominator in the formula takes the form of an exponential function and has good mathematical properties. As the environmental impact index increases, the value of the denominator will grow rapidly, resulting in a decrease. This design logic is reasonable: the greater the environmental impact, the lower the stability index of the culvert, reflecting the negative impact of environmental conditions on the structural stability. The parameter is the control factor of the environmental impact index. Its positive value means that the growth of environmental impact will affect the stability index exponentially, and this non-linear relationship can more sensitively reflect the risks brought by environmental changes. If increases, it indicates that the impact of environmental factors plays a more important role in the stability index, enhancing the flexibility and adaptability of the formula. The parameter as the threshold parameter of the environmental impact index helps to set a critical point and affect the effect of the environmental impact index. When is less than , the value of the denominator is relatively small, and the relationship between and is relatively strong; while when exceeds , the environmental impact quickly enters the non-linear region, inhibiting the growth of the stability index and emphasizing the significant impact that environmental conditions beyond the threshold may have on stability. Due to the characteristics of the exponential function, when there are minor changes in environmental impact factors, the impact of the exponent will be amplified rapidly, enabling the safety index to promptly reflect the trend of decreasing stability and providing early warning of potential hazards.

[0051] is a comprehensive index used to evaluate the overall stability of the culvert under specific environmental conditions. It combines the comprehensive safety factor of this sampling point and environmental impact factors, quantifying the safety level of the culvert. The higher the stability index, the better the stability and safety of the culvert at this sampling point. On the contrary, a lower stability index may indicate potential risks or unsafe factors. Therefore, aims to provide engineers with a clear and quantitative safety assessment tool for taking corresponding measures during monitoring and maintenance. By using this stability index, dynamic monitoring of the culvert structure can be achieved in practical applications, quickly identifying risk points and taking corresponding preventive measures, thereby improving the safety and reliability of the structure. The independent variables are the comprehensive safety factor and the environmental impact index. The comprehensive safety factor reflects the safety of the culvert structure itself in terms of design, material strength, and other static factors, and the environmental impact index comprehensively considers the influence of factors such as temperature, humidity, and soil compaction on the stability of the culvert. An increase in will directly increase , while an increase in value and decrease its numerical value. In other words, a good structural design (high ) can improve the stability index, but if the environmental impact is significant (high ), it may offset or weaken this effect. There is a positive correlation between the comprehensive safety index and the stability index , that is, when increases, also increases, indicating an improvement in the basic safety of the structure. There is an inverse correlation between the environmental impact index and the stability index . As the environmental impact index increases, the value of the denominator will increase, resulting in a decrease in . This reflects that the deterioration of environmental conditions has a negative impact on the stability of the culvert.

[0052] If there is no sampling point in the culvert marked as having poor stability, calculate the mean of the stability indices of all sampling points in the culvert as the stability index of the culvert. If there are sampling points in the culvert marked as having poor stability, the formula for calculating the stability index of the culvert is: ; where SI is the stability index of the culvert at the current moment, n is the total number of sampling points not marked as having poor stability, is the stability index of the sampling point not marked as having poor stability at the current moment, x is the index of the sampling point not marked as having poor stability, and , m is the total number of sampling points marked as having poor stability, is the stability index of the sampling point marked as having poor stability at the current moment, y is the index of the sampling point marked as having poor stability, and , are the weight coefficients of the corresponding terms respectively, ; Judge the load borne by the culvert at the current moment. If the load borne by the culvert at the current moment has reached the maximum simulated load that the culvert can bear, directly mark the stability of the culvert at the current moment as poor. If the culvert at the current moment has not reached the maximum simulated load that the culvert can bear, judge the stability index of the culvert, compare the stability index of the culvert with the preset stability threshold. If the stability index of the culvert is higher than the preset stability threshold, it indicates that the culvert is in a good stability state at the current moment. If the stability index of the culvert is lower than the preset stability threshold, it indicates that the culvert is in a poor stability state at the current moment.

[0053] This method combines the analysis of the volatility and stability index of sampling points, enabling a more comprehensive assessment of the overall stability of the culvert. By comparing the volatilities, it is possible to identify which sampling points have stability problems, thus allowing for targeted attention. By classifying the sampling points into two categories: "marked as poor stability" and "not marked as poor stability", it can be used to determine how many sampling points in the culvert are in an unstable state at that time. If it exceeds half of the total number of sampling points, it is marked. Here, different weight relationships are used for the analysis of the stability index of the sampling points marked as poor stability and those not marked as poor stability. By paying more attention to the sampling points marked as poor stability, the overall stability of the culvert can be evaluated more comprehensively and accurately.

[0054] The stability index SI of the culvert is a comprehensive index used to evaluate the overall safety and stability of the culvert under specific conditions. It comprehensively considers the stability indices of the sampling points not marked as poor stability and those marked as poor stability, and performs a weighted average according to their weights. The value of the stability index can directly reflect the safety state of the culvert. When SI is higher than the preset stability threshold, the culvert is in a good stable state; otherwise, it indicates the existence of structural risks and further monitoring or maintenance is required.

[0055] The stability index of the sampling points not marked as poor stability represents the safety of these sampling points under the current environment and conditions; the stability index of the sampling points marked as poor stability indicates that the safety of these sampling points is generally poor and potential hazards may exist. There is a direct positive correlation with SI. The stability of the sampling points not marked as poor stability directly affects the overall stability index. There is also a direct positive correlation with SI. However, when allocating weights, based on a higher weight, it indicates more attention is paid to the stability of these sampling points that have been analyzed to potentially have poor stability. The stability indices of both types of sampling points and the stability index of the culvert are positively correlated. The overall stability index of the culvert depends on the stability indices of each sampling point. The larger the stability index of each sampling point, the larger the stability index of the culvert; conversely, the smaller the stability index of the culvert.

[0056] Please refer to Figure 2 This invention also provides a stability analysis device for a highway prefabricated culvert. The stability analysis device for a highway prefabricated culvert is used to implement the above-mentioned stability analysis method for a highway prefabricated culvert, and includes: A data acquisition and correction module, which is used to collect the service life, geometric parameters and material properties of the culvert, determine the sampling points of the culvert, collect the environmental data at the sampling points, analyze the influence of the environmental data on the material properties of the culvert, introduce a time-dependent correction factor according to the service life of the culvert, and obtain the corrected material properties of the culvert; A finite element model establishment module, which is used to establish a finite element model of the culvert based on the geometric parameters and the corrected material properties of the culvert, conduct a simulated load test on the finite element model, input the simulated load into the finite element model, and obtain the maximum simulated load; An actual load analysis module, which is used to obtain the actual loads of the culvert at the first N moments, input the actual loads of the culvert at the first N moments into the finite element model, obtain the stress and displacement at the sampling points of the culvert, analyze the stability of each sampling point of the culvert at the first N moments, and mark the sampling points with poor stability; A stability evaluation module, which is used to generate a stability index of the culvert at the current moment by combining the stability of each sampling point of the culvert at the first N moments and the environmental data and soil compactness at the sampling points of the culvert at the current moment, and determine whether the culvert is stable at the current moment by analyzing the stability index of the culvert.

[0057] The above formulas are all dimensionless and take their numerical values for calculation. The formulas are obtained by collecting a large amount of data for software simulation to get a formula that is closest to the actual situation. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0058] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, or by the combination of computer software and electronic hardware. Whether these functions are executed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0059] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units. They may be located in one place, or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0060] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in this application, and all of them should be covered by the protection scope of this application.

Claims

1. A method for analyzing the stability of a highway assembled box culvert, characterized in that: The specific steps include: Step 1: Collect the service life, geometric parameters and material properties of the box culvert, determine the sampling points of the box culvert, collect environmental data at the sampling points to analyze the impact of environmental data on the material properties of the box culvert, introduce a time-dependent correction factor based on the service life of the box culvert, and obtain the corrected material properties of the box culvert; Step 2: Based on the geometric parameters of the box culvert and the corrected material properties, a finite element model of the box culvert is established, a simulated load test is performed on the finite element model, and the simulated load is input into the finite element model to obtain the maximum simulated load; Step 3: Obtain the actual load of the box culvert at the first N moments, input the actual load of the box culvert at the first N moments into the finite element model, obtain the stress and displacement at the sampling points of the box culvert, analyze the stability of each sampling point of the box culvert at the first N moments, and mark the sampling points with poor stability; Step 4: Combine the stability of each sampling point of the box culvert at the previous N moments with the environmental data and soil density at the sampling point of the box culvert at the current moment to generate the stability index of the box culvert at the current moment. By analyzing the stability index of the box culvert, determine whether the box culvert is stable at the current moment.

2. A method for analyzing the stability of a highway assembled box culvert according to claim 1, characterized in that: Establishing the finite element model of the box culvert specifically includes: The geometric parameters of the box culvert include the length, width and height of the box culvert, and the material properties include elastic modulus, compressive strength and density. The middle position of the top of the box culvert, the corner and the middle position of the joint are set as sampling points of the box culvert. The environmental data include ambient temperature and ambient humidity. Temperature sensors and humidity sensors are arranged at the sampling points to collect temperature and humidity data at the sampling points. The influence of the temperature and humidity data of each sampling point on the elastic modulus in the material properties of the box culvert is analyzed to obtain the elastic model after the influence of temperature and humidity data. The calculation formula is: ； in, is the elastic modulus of the ith sampling point after the influence of temperature and humidity data, is the initial elastic modulus, is the ambient temperature of the i-th sampling point, is the ambient humidity of the i-th sampling point, are the reference values ​​of temperature and humidity, respectively, and a and b are the corresponding weight coefficients; According to the service life of the box culvert, the time-dependent correction factor is obtained, and the calculation formula is: ； in, is the time-dependent correction factor, is the empirical coefficient in the elastic modulus, For the useful life, is the reference time; The elastic modulus after the time-dependent correction factor is introduced to correct the influence of environmental data is calculated as follows: ； in, is the elastic modulus of the ith sampling point after correction by environmental data and service life; The time-dependent correction factor is introduced to correct the initial compressive strength of the box culvert. The calculation formula is: ； in, is the compressive strength of the box culvert after correction by the time-dependent correction factor, is the initial compressive strength, is the empirical coefficient in compressive strength.

3. The stability analysis method of a highway assembled box culvert according to claim 1 is characterized in that: Obtaining the stress and displacement data of the finite element model under various loads specifically includes: The geometric model of the three-dimensional box culvert is established by using the finite element analysis software. The length, width and height of the box culvert are input, as well as the compressive strength and density of the box culvert and the elastic modulus of each sampling point of the box culvert. The eight-node brick element is selected to mesh the finite element model of the box culvert. The displacement of the nodes at the bottom of the box culvert in the X direction, Y direction and Z direction are all set to 0. The elastic soil model is selected, and the surface where the bottom of the box culvert contacts the soil is used as the contact surface. The displacement constraint is applied to the side of the finite element model of the box culvert to 0, and the vertical displacement is set to allow up and down movement. When the model is applied with vertical displacement, the corresponding soil reaction force is applied at the same time. Then apply a simulated load to the top contact surface of the finite element model of the box culvert, select the static analysis solver, and gradually increase the applied load from small to large when applying the load, and repeat the finite element analysis until the maximum stress of the model reaches the compressive strength of the box culvert after correction by the time-dependent correction factor. At this time, it is considered that the maximum simulated load that the box culvert can withstand has been reached, the load application will be stopped, and the maximum simulated load that the box culvert can withstand will be recorded.

4. A method for analyzing the stability of a highway assembled box culvert according to claim 3, characterized in that: The analysis of the stress and displacement at the sampling point of the box culvert specifically includes: Record the type and number of vehicles passing through the box culvert at each moment, calculate the actual load of the box culvert at each moment, input the actual load of the box culvert at the previous N moments into the finite element model, output the stress and displacement data of the box culvert sampling points through the finite element model, analyze the safety factor of the box culvert at each moment, and calculate the stress safety factor formula as follows: ； in, is the stress safety factor of the i-th sampling point at time t, is the compressive strength of the box culvert after correction by the time-dependent correction factor, is the stress of the i-th sampling point at time t output by the finite element model; The formula for calculating the displacement safety factor is: ； in, is the displacement safety factor of the i-th sampling point at time t, is the displacement of the i-th sampling point at time t output by the finite element model, The maximum allowable displacement set by the design code.

5. A method for analyzing the stability of a highway assembled box culvert according to claim 4, characterized in that: The sampling points with poor stability are specifically marked as follows: The comprehensive safety factor of the i-th sampling point at time t is comprehensively analyzed based on the stress safety factor and displacement safety factor. The calculation formula is: ； in, is the comprehensive safety factor of the i-th sampling point at time t, are the weight coefficients of the corresponding items, ,and ; Calculate the mean and standard deviation of the comprehensive safety factor of each sampling point in the first N moments of the box culvert. According to the mean and standard deviation of the comprehensive safety factor of each sampling point, obtain the volatility of each sampling point in the first N moments. The calculation formula is: ； in, is the volatility of the ith sampling point, is the standard deviation of the comprehensive safety factor of the i-th sampling point, is the mean value of the comprehensive safety factor of the i-th sampling point; Calculate the mean volatility of all sampling points of the box culvert, compare the volatility of each sampling point with the mean volatility, if the number of sampling points with volatility higher than the mean volatility is less than half of the total number of sampling points, then do not mark the sampling points; if the number of sampling points with volatility higher than the mean volatility is higher than or equal to half of the total number of sampling points, then mark the sampling points higher than the mean volatility as having poor stability.

6. A method for analyzing the stability of a highway assembled box culvert according to claim 5, characterized in that: Based on soil density, temperature and humidity data, the environmental impact index is generated, and the calculation formula is: ； in, is the environmental impact index of the i-th sampling point, is the ambient temperature of the i-th sampling point, is the humidity calculation function of the i-th sampling point, is the soil density of the i-th sampling point, , , are the weight coefficients of the corresponding items, ,and ; The humidity calculation function is as follows: ； in, is the ambient humidity of the i-th sampling point, is the maximum value within the suitable humidity range. It is the minimum value within the suitable humidity range.

7. A method for analyzing the stability of a highway assembled box culvert according to claim 6, characterized in that: Generating the stability index of the box culvert at the current moment specifically includes: According to the comprehensive safety factor and environmental impact index of each sampling point of the box culvert, the stability index of each sampling point of the box culvert is generated. The calculation formula is: ； in, is the stability index of the i-th sampling point at the current moment, is the comprehensive safety factor of the i-th sampling point at the current moment, is the control factor of the environmental impact index, is the threshold parameter of the environmental impact index, ; If there is no sampling point in the box culvert marked as poor stability, the mean of the stability index of all sampling points in the box culvert is calculated as the stability index of the box culvert. If there is a sampling point in the box culvert marked as poor stability, the formula for calculating the stability index of the box culvert is: ； Among them, SI is the stability index of the box culvert at the current moment, n is the total number of sampling points that are not marked as poor stability, is the stability index of the sampling point that is not marked as poor stability at the current moment, x is the index of the sampling point that is not marked as poor stability, and , m is the total number of sampling points marked as having poor stability, is the stability index of the sampling point marked as poor stability at the current moment, y is the index of the sampling point marked as poor stability, and , are the weight coefficients of the corresponding items, ; The load borne by the box culvert at the current moment is judged. If the load borne by the box culvert at the current moment has reached the maximum simulated load that the box culvert can withstand, the stability of the box culvert at the current moment is directly marked as poor. If the box culvert at the current moment has not reached the maximum simulated load that the box culvert can withstand, the stability index of the box culvert is judged, and the stability index of the box culvert is compared with the preset stability threshold. If the stability index of the box culvert is higher than the preset stability threshold, it indicates that the box culvert is in a good stability state at the current moment. If the stability index of the box culvert is lower than the preset stability threshold, it indicates that the box culvert is in a poor stability state at the current moment.

8. A stability analysis device for a highway assembled box culvert, characterized in that: The stability analysis device for a highway prefabricated box culvert is used to implement the stability analysis method for a highway prefabricated box culvert according to any one of claims 1 to 7, comprising: The data collection and correction module is used to collect the service life, geometric parameters and material properties of the box culvert, determine the sampling points of the box culvert, collect environmental data at the sampling points, analyze the impact of environmental data on the material properties of the box culvert, introduce a time-dependent correction factor according to the service life of the box culvert, and obtain the corrected material properties of the box culvert; The finite element model building module is used to build a finite element model of the box culvert based on the geometric parameters of the box culvert and the corrected material properties, conduct a simulated load test on the finite element model, input the simulated load into the finite element model, and obtain the maximum simulated load; The actual load analysis module is used to obtain the actual load of the box culvert at the previous N moments, input the actual load of the box culvert at the previous N moments into the finite element model, obtain the stress and displacement at the sampling points of the box culvert, analyze the stability of each sampling point of the box culvert at the previous N moments, and mark the sampling points with poor stability; The stability assessment module is used to combine the stability of each sampling point of the box culvert at the previous N moments and the environmental data and soil density at the sampling point of the box culvert at the current moment to generate the stability index of the box culvert at the current moment, and determine whether the box culvert is stable at the current moment by analyzing the stability index of the box culvert.

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