A flood season bridge water level monitoring and early warning method and system

Abstract

The present invention relates to the field of bridge operation safety, and specifically to a method and system for monitoring and warning of bridge water levels during flood season. The method comprises the following steps: constructing a flood season bridge safety water level line system; setting a flood season bridge safety water level mark based on the flood season bridge safety water level line system; obtaining the water depth at the bridge pier based on the flood season bridge safety water level mark; obtaining the monitoring result of the water level under the bridge according to the water depth at the bridge pier; and realizing the risk warning of the water level under the bridge during flood season through the monitoring result. The present invention constructs a standardized and visual water level identification system by color-coding and grading water level lines and adding warning water level prompt signs, effectively making up for the functional limitations of existing water level marks, significantly improving the accuracy of bridge safety monitoring during flood season and the timeliness of emergency response; utilizing the Karman vortex street effect and low-concentration ion labeling technology to monitor water depth, realizing real-time warning of water level exceeding the limit, and providing a quantitative basis for bridge safety assessment and emergency closure.

Description

Technical Field

[0001] The present invention relates to the field of bridge operation safety, and in particular to a flood season bridge water level monitoring and early warning method and system. Background Art

[0002] The water level beneath a bridge is a key indicator of the safety of highway bridges during flood season. When the water level beneath a bridge exceeds the design level, the bridge's substructure, including piers and abutments, may experience prolonged exposure to the significant impact of the water flow and floating objects, leading to changes in stress states and potentially posing safety risks. Furthermore, high water levels can cause floodwaters to soak, impact, and lift non-water-related components of the bridge's main beams, arches, and supports. This increases the risk of passing vessels striking the bridge's superstructure, seriously impacting the overall safety of the bridge structure.

[0003] In existing technology, water level markers under bridges primarily include navigational levels and flood control levels. Navigable levels are set based on ship traffic requirements to prevent ships from running aground during low water levels and colliding with bridge superstructures during high water levels. Flood control levels, on the other hand, are based on embankment safety requirements and are used for flood control authorities' alerts and emergency response. However, these water level markers are not designed to address the inherent safety needs of bridges and are unable to directly reflect the safety status of bridge structures during flood season. This results in insufficient early warning of bridge water damage risks and makes it difficult to provide accurate and intuitive decision-making for bridge safety management.

[0004] At present, there is not much research on the safety monitoring and early warning of water levels under bridges during flood season, and there is no specific systematic, standardized and refined method for monitoring and early warning of water levels under bridges during flood season. Summary of the Invention

[0005] In view of the defects in the prior art, the present invention provides a method and system for monitoring and early warning of bridge water levels during flood season.

[0006] In a first aspect, the present invention provides a method for monitoring and early warning of bridge water levels during flood season, comprising the following steps: constructing a bridge safety water level line system during flood season, wherein the bridge safety water level line system during flood season includes a historical maximum flood level, a safe operation benchmark water level, and a defense warning water level; setting a bridge safety water level mark during flood season based on the bridge safety water level line system; obtaining the water depth at the bridge pier based on the bridge safety water level mark during flood season by utilizing the Karman vortex street effect and low-concentration ion labeling technology; obtaining monitoring results of the water level under the bridge based on the water depth at the bridge pier; and realizing early warning of the water level under the bridge during flood season through the monitoring results. The present invention constructs a safe water level line system for bridges during flood season, incorporates the historical maximum flood level, safe operation benchmark water level and defense warning water level into a unified framework, realizes the quantitative classification of water level risks under bridges, and provides a scientific basis for early warning decisions; by setting safe water level signs for bridges during flood season, it intuitively displays the risk levels corresponding to different water levels, and improves the ability of on-site personnel to quickly judge the severity of flood conditions; by utilizing the Karman vortex street effect and low-concentration ion labeling technology to obtain the water depth at the bridge piers, it breaks through the limitations of traditional water level monitoring caused by environmental interference such as turbulent water flow and high sediment content, and significantly improves the accuracy and reliability of data under complex hydrological conditions; by obtaining the water depth at the bridge piers in real time and analyzing the monitoring results, it realizes dynamic tracking of water level changes, and gains valuable time for early warning response; by linking the analysis of monitoring results and the safe water level line system, it realizes refined processing from data collection to risk warning, greatly reduces the probability of human misjudgment, and effectively improves the efficiency and accuracy of bridge safety management during flood season.

[0007] Optionally, constructing a flood season bridge safety water level system includes: determining a defense warning water level; determining a safe operation reference water level; determining a historical maximum flood level; and constructing a flood season bridge safety water level system through the defense warning water level, the safe operation reference water level and the historical maximum flood level. By determining the defense warning water level, the present invention is conducive to establishing a primary warning threshold for the risks faced by bridges during flood season, so that management personnel can take preventive measures in time at the early stage of floods and reduce the potential threat of sudden floods to bridge structures. By determining the safe operation benchmark water level, the water level upper limit for normal operation of the bridge is clarified, which provides an objective standard for daily management and flood season safety assessment, and ensures that the bridge operates stably within a controllable water level range. By determining the historical maximum flood level, a key historical basis is provided for the design of bridge flood resistance and water level warning system, and the ability to cope with super-standard floods is enhanced. By integrating the defense warning water level, the safe operation benchmark water level and the historical maximum flood level, a flood season bridge safety water level line system is constructed, forming a multi-level and progressive water level monitoring and early warning framework, which realizes full process coverage from daily monitoring to emergency response, improves the systematic and scientific nature of bridge flood control management, and provides refined and standardized decision-making support for flood season water level monitoring and early warning.

[0008] Optionally, determining the defense warning water level includes: determining the verification flood flow; using the verification flood flow to establish a calculation expression for the flow at the riverbed section at the bridge position; according to the calculation expression, obtaining the hydraulic radius of the river channel and the river beach; using the hydraulic radius to determine the flood water level; based on the flood water level, establishing a calculation model for the height of the backwater in front of the bridge; according to the calculation model, obtaining the height of the backwater in front of the bridge; and determining the defense warning water level through the flood water level and the height of the backwater in front of the bridge. By determining and verifying flood flow, the present invention provides a scientific hydrological calculation basis for bridge water level warning, ensuring that the setting of the defense warning water level conforms to the actual flood characteristics; by establishing a calculation expression for the flow at the riverbed section at the bridge position, it realizes the accurate simulation of the water flow in complex rivers and improves the accuracy of water level prediction; by calculating the hydraulic radius of the river channel and the river beach, it accurately reflects the water flow resistance characteristics of different river sections and optimizes the reliability of water level calculation; by determining the flood water level, it quantifies the potential threat degree of floods to bridges; by establishing a calculation model for the height of backwater in front of the bridge, it effectively evaluates the blocking effect of the bridge structure on the water flow and avoids the risk of water level underestimation due to the backwater effect; the defense warning water level is determined by the flood water level and the height of backwater in front of the bridge, which takes into account both the natural flood level and the water blocking effect of the bridge, making the monitoring and early warning mechanism more engineering-oriented and safe.

[0009] Optionally, the flow rate at the riverbed section at the bridge location is calculated as follows:

[0010] ,

[0011] in, To calculate flood flow, 、 are the water-flowing areas of the river channel and riverbank respectively. 、 are the riverbed roughness coefficients of the river channel and riverbank, 、 are the hydraulic radius of the river channel, is the riverbed gradient; the calculation model of the backwater height in front of the bridge satisfies the following expression:

[0012] ,

[0013] in, is the maximum water level in front of the bridge, is the average flow velocity of the natural section in front of the bridge, is the coefficient related to the pier shape, is the acceleration due to gravity, is the average flow velocity under the bridge section before scouring, is the median particle size of bed sand, is the average flow velocity of a natural river channel. By constructing a flow calculation expression for the river channel and river beach, the present invention achieves a refined calculation of flood flow in a composite cross-section river channel, fully considering the differences in water flow characteristics in different regions and significantly improving the accuracy of flow distribution. By synchronously calculating the average flow velocity of the river beach, the defect of the existing method of ignoring the influence of the river beach is overcome, and the full-section flow assessment system is improved. By establishing a model for the height of backwater in front of the bridge, the water blocking effect of the bridge is quantified. By correlating the median particle size of the bed sand with the river channel flow velocity parameters, the regulatory effect of the riverbed's anti-scouring characteristics on the backwater height is reflected, so that the model has the dual theoretical support of hydraulics and sediment kinematics, and ultimately outputs high-precision calculation results.

[0014] Optionally, determining the safe operation reference water level includes: determining the safe operation reference water level that takes into account the falling beams of the bridge superstructure to obtain a first safe operation reference water level; determining the safe operation reference water level that takes into account the displacement of the bridge piers due to dynamic water pressure and impact of floating objects to obtain a second safe operation reference water level; determining the safe operation reference water level that takes into account the collapse of the bridge piers due to dynamic water pressure and impact of floating objects to obtain a third safe operation reference water level; determining the safe operation reference water level that takes into account the bridge cone slope protection and the hollowing out of the bridge-road transition section to obtain a fourth safe operation reference water level; determining the safe operation reference water level that takes into account driving safety to obtain a fifth safe operation reference water level; and determining the minimum value of the first safe operation reference water level, the second safe operation reference water level, the third safe operation reference water level, the fourth safe operation reference water level and the fifth safe operation reference water level as the overall safe operation reference water level. The present invention determines the safe operation reference water level considering five risks, namely, bridge superstructure beam drop, pier displacement, pier collapse, cone slope protection hollowing and driving safety, and constructs a systematic water level assessment system covering the entire safe operation failure mode of the bridge structure, breaking through the limitations of the traditional single water level limit. By determining the safe operation reference water level for the risk of bridge superstructure beam drop, the invention prevents instability accidents caused by excessive buoyancy of the beam body due to excessive water level. By determining the safe operation reference water level for the risk of pier displacement, the invention controls the combined destructive effect of dynamic water pressure and floating object impact on the stability of the pier column. By targeting the risk of bridge pier collapse, the safe operating benchmark water level is determined, thereby avoiding the catastrophic consequences of foundation scouring and structural strength failure; by targeting the risk of cone slope protection hollowing, the safe operating benchmark water level is determined, thereby blocking the chain damage path of auxiliary structures caused by soil erosion; by targeting driving safety, the safe operating benchmark water level is determined, thereby ensuring the interactive safety of vehicles and bridges when driving through water; by selecting the minimum value of the five types of water level limits as the overall safe operating benchmark water level, it is ensured that any single risk factor will not exceed the overall safety threshold, thereby achieving the most conservative safety guarantee under the effect of multi-dimensional risk coupling.

[0015] Optionally, the determination of the safe operating reference water level considering the falling beams of the bridge superstructure includes: establishing a critical water level model for preventing falling beams, and determining the safe operating reference water level considering the falling beams of the bridge superstructure based on the critical water level model for preventing falling beams; the determination of the safe operating reference water level considering the displacement of the bridge piers due to the dynamic water pressure and the impact of floating objects includes: establishing a critical water level model for the piers to resist displacement, and determining the safe operating reference water level considering the displacement of the bridge piers due to the dynamic water pressure and the impact of floating objects based on the critical water level model for the piers to resist displacement; the determination of the safe operating reference water level considering the collapse of the bridge piers due to the dynamic water pressure and the impact of floating objects includes: establishing a critical water level model for the piers to resist displacement, and determining the safe operating reference water level considering the collapse of the bridge piers due to the dynamic water pressure and the impact of floating objects A critical water level model is established, and based on the bridge pier anti-collapse critical water level model, a safe operating reference water level is determined that takes into account the collapse of the bridge pier due to dynamic water pressure and impact of floating objects; the determination of the safe operating reference water level that takes into account the hollowing of the bridge cone slope protection and the bridge-road transition section includes: establishing a bridge area water-soil coupled anti-corrosion critical water level model, and based on the bridge area water-soil coupled anti-corrosion critical water level model, determining the safe operating reference water level that takes into account the hollowing of the bridge cone slope protection and the bridge-road transition section; the determination of the safe operating reference water level that takes into account driving safety includes: establishing a driving safety critical water level model, and determining the safe operating reference water level that takes into account driving safety based on the driving safety critical water level model. The present invention ensures the stability of the bridge superstructure during floods by establishing a critical water level model for preventing beam fall; prevents structural instability caused by pier column deviation by establishing a critical water level model for preventing pier collapse; avoids catastrophic collapse accidents by establishing a critical water level model for water-soil coupling erosion prevention in the bridge area; and ensures driving safety during flood season by establishing a driving safety water level model.

[0016] Optionally, the critical water level model of the anti-fall beam satisfies the following relationship:

[0017] ,

[0018] in, Indicates that the critical water level is The lateral thrust on the bridge superstructure is Indicates that the critical water level is The lateral resistance of the bridge superstructure is: The critical water level model of the pier anti-deflection satisfies the following relationship:

[0019] ,

[0020] in, The critical water level is The displacement of the top of the pier is is the maximum displacement of the pier allowed during the bridge operation phase; the critical water level model for pier collapse resistance satisfies the following relationship:

[0021] ,

[0022] in, The critical water level is The maximum bending moment of the bridge pier is represents the design bending bearing capacity of the bridge pier; the bridge area water-soil coupled anti-corrosion critical water level model satisfies the following relationship:

[0023] ,

[0024] in, The critical water level is The vertical distance between the escape point and the toe of the back water surface; the critical water level model for driving safety satisfies the following relationship:

[0025] ,

[0026] in, Indicates the critical water level, Indicates the lowest elevation of the bridge beam bottom. Represents the clearance safety value between the design flood level and the bottom elevation of the beam. By constructing a critical water level model for preventing beam drop, the present invention achieves precise balance control between the lateral thrust and structural resistance exerted on the bridge superstructure, ensuring that the stability of the beam body is still within the safety threshold when the water level reaches the critical water level; by constructing a critical water level model for pier anti-deflection, the displacement of the top of the pier is strictly limited to the maximum allowable deviation range, preventing the pier column from tilting due to the water level reaching the critical water level, resulting in failure of the structural system; by constructing a critical water level model for pier anti-collapse, it is ensured that the pier body bending moment does not exceed the design bending bearing capacity when the water level reaches the critical water level, eliminating the risk of pier column fracture from the strength theory level; by constructing a critical water level model for water-soil coupling erosion prevention in the bridge area, the state of soil and water erosion when the water level reaches the critical water level is scientifically defined with the escape point reaching the slope foot as the judgment standard; by constructing a critical water level model for driving safety, half of the clearance safety value is retained between the bottom elevation of the beam and the flood level, fully ensuring the safety of vehicle traffic.

[0027] Optionally, setting the flood season bridge safety water level sign based on the flood season bridge safety water level line system includes: designing the flood season bridge safety water level sign based on the flood season bridge safety water level line system, and obtaining the design results of the font type, water level scale text height, water level scale width, graded water level line width, graded water level line text color, background color, sign making material, water level scale accuracy, reading range requirements, setting position and fixing method of the flood season bridge safety water level sign; and setting the flood season bridge safety water level sign according to the design results. The present invention ensures the clear recognition of the sign information under complex meteorological conditions by designing the font type of the water level sign and the height of the water level line scale text; by standardizing the water level scale width and the graded water level line width, it realizes the intuitive distinction of water levels of different risk levels, which is convenient for rapid interpretation during the flood season; by setting the contrasting combination of the graded water level line text color and the background color, the visual warning effect of the sign is enhanced, and the visibility in extreme weather is improved; by optimizing the sign production material, the durability of the sign in a long-term sun and rain environment is guaranteed; by limiting the water level scale accuracy, the technical requirements of high-precision water level monitoring are met; by clarifying the reading range requirements of the sign, the accurate readings of monitoring personnel at different observation distances are ensured; by scientifically setting the sign position and fixing method, a stable combination of the sign and the bridge structure is achieved, avoiding displacement or damage caused by flood impact.

[0028] Optionally, obtaining the water depth at the bridge pier based on the flood season bridge safety water level mark by using the Karman vortex street effect and low-concentration ion labeling technology includes: establishing a relationship model between the shedding frequency of the Karman vortex street and the water flow velocity at the bridge pier based on the flood season bridge safety water level mark by using the Karman vortex street effect, wherein the relationship model satisfies the following expression:

[0029] ,

[0030] in, is the shedding frequency of the Karman vortex street, is the Strouhal number, is the width of the bridge pier's water-facing projection, is the water flow velocity at the bridge pier; using low-concentration ion labeling technology, the shedding frequency of the Karman vortex street is obtained; according to the relationship model and the shedding frequency of the Karman vortex street, the flow velocity at the bridge pier is obtained;

[0031] The relationship between the flow rate and the hydraulic radius is established as follows:

[0032] ,

[0033] in, is the water velocity at the bridge pier, is the hydraulic radius, is the riverbed roughness coefficient, is the riverbed gradient; based on the relationship, combined with the measurement results of the river channel size at the bridge site, the water depth at the bridge pier is obtained. The present invention establishes a relationship model between the shedding frequency and the water flow velocity by utilizing the Karman vortex street effect, realizes non-contact flow velocity measurement based on the principle of fluid dynamics, and overcomes the vulnerability of existing mechanical flow meters under high flow conditions during the flood season; by adopting low-concentration ion labeling technology, it breaks through the technical bottleneck of vortex street signal capture in turbid water bodies, ensuring the accuracy of frequency measurement under complex hydrological environments; by establishing a relationship between flow velocity and hydraulic radius, the point flow velocity is expanded to a cross-sectional hydraulic parameter, providing a theoretical basis for water depth calculation; by combining the measured data of the river channel size, the boundary condition error of the theoretical model is corrected, making the water depth calculation more consistent with the actual river channel morphology; through multi-physical field coupling measurement, a new flood season water depth monitoring method with strong anti-interference, high precision and wide adaptability is formed, providing reliable hydrological data support for bridge safety warning.

[0034] In the second aspect, the present invention provides a flood season bridge water level monitoring and early warning system, comprising an input device, a processor, an output device and a memory, wherein the input device, the processor, the output device and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, the processor is configured to call the program instructions, and the system uses the flood season bridge water level monitoring and early warning method. The system provided by the present invention has a high degree of integration, and information transmission between various components is smooth; by constructing a multi-level water level line system, dynamic hierarchical monitoring and early warning of bridge flood season risks are achieved; by coupling computational structural mechanics with hydrological characteristics, the early warning threshold simultaneously meets the multiple requirements of beam fall protection, bridge pier stability, and driving safety; by integrating Karman vortex street velocity measurement and ion labeling technology, the problem of flow velocity monitoring under high sand content, turbulent and complex hydrological conditions is overcome, and the single-point flow velocity is converted into cross-sectional water depth information, which greatly improves the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of a flood season bridge water level monitoring and early warning method according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic structural diagram of a flood season bridge safety water level marker according to an embodiment of the present invention;

[0037] Figure 3 Schematic diagram of the structure of a flood season bridge water level monitoring and early warning system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the present invention. In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that these specific details are not necessarily required to practice the present invention. In other instances, well-known circuits, software, or methods are not specifically described to avoid obscuring the present invention.

[0039] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "in one embodiment," "in an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combinations and / or subcombinations in one or more embodiments or examples. Furthermore, those of ordinary skill in the art will appreciate that the figures provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0040] See Figure 1 , an embodiment of the present invention provides a flood season bridge water level monitoring and early warning method, the method comprising the following steps:

[0041] S1. Construct a bridge safety water level system during flood season, wherein the bridge safety water level system during flood season includes the historical maximum flood level, the safe operation benchmark water level, and the defense warning water level.

[0042] Among them, S1 includes the following steps:

[0043] S11. Determine the warning water level.

[0044] The defense warning water level refers to the specific height at which a bridge may face initial safety risks when the water level reaches this specific height. As the water level continues to rise or further rises, the degree of danger encountered by the bridge will increase accordingly. The calculation formula for the defense warning water level is as follows:

[0045]

[0046] in, To set a warning water level, is the flood level, It is the height of water in front of the bridge.

[0047] In one embodiment, by calculating the flood level and the height of the water in front of the bridge , combined with the above calculation formula for the defense warning water level, determine the defense warning water level.

[0048] Specifically, first determine the verification flood flow for the defense warning water level. Unless otherwise specified, the verification flood flow for the defense warning water level is estimated using the frequencies given in Table 1 in conjunction with the "Specifications for Hydrological Survey and Design of Highway Engineering" (JTG C30-2015). For bridges in mountainous areas, the verification flood flow for the defense warning water level is estimated using the frequencies given in Table 2 in conjunction with the "Specifications for Hydrological Survey and Design of Highway Engineering" (JTG C30-2015).

[0049]

[0050]

[0051] Furthermore, the flow-water level curve at the riverbed section at the bridge location is drawn.

[0052] Specifically, the flow calculation expression at the riverbed section at the bridge location is as follows:

[0053]

[0054] in, To verify flood flow, unit: , 、 They are the water-flowing areas of the river channel and river beach, respectively, in units of: , 、 are the average flow velocities of the river channel and riverbank, respectively, in units: ; Satisfies the following expression:

[0055]

[0056] in, is the riverbed roughness coefficient of the river channel, is the hydraulic radius of the river channel, unit: When the width-to-depth ratio of the section is greater than 10, the average water depth can be used instead. is the riverbed gradient; Satisfies the following expression:

[0057]

[0058] in, is the riverbed roughness coefficient of the river beach, is the hydraulic radius of the riverbank, unit: When the width-to-depth ratio of the section is greater than 10, the average water depth can be used instead. It is the riverbed gradient.

[0059] Furthermore, the above relationship can be sorted out to obtain:

[0060] ,

[0061] Furthermore, the hydraulic radius of the river channel and riverbank can be obtained according to the above expressions: 、 ,

[0062] Furthermore, according to the hydraulic radius of the river channel and riverbank 、 , determine the flood level .

[0063] Furthermore, based on the flood water level and the calculated flood flow, a flow-water level curve at the riverbed section at the bridge location is drawn.

[0064] It should be noted that the hydraulic radius of the river channel and riverbank 、 Flood level and the riverbed cross-sectional shape, therefore, in verifying the flood flow Based on the determined data, the flood level is determined by combining the flow calculation expression at the riverbed section at the bridge location. .

[0065] Furthermore, the height of the water in front of the bridge is calculated.

[0066] Specifically, for rivers in mountainous areas and piedmont areas, where floods rise and fall rapidly, last for a short time, and the riverbed is solid and not easily eroded, the height of the backwater under the bridge can be the maximum backwater value in front of the bridge. The height of the backwater in front of the bridge is mainly affected by the water blocking effect of the bridge piers and is calculated according to the following relationship:

[0067] ,

[0068] in, The maximum water level in front of the bridge, unit: , is the average flow velocity of the natural section in front of the bridge, unit: , The coefficient related to the shape of the pier is 0.35 for rectangular piers and 0.18 for circular piers. Other pier shapes can be set between 0.18 and 0.35 according to the water blocking conditions. is the acceleration due to gravity, is the average flow velocity under the bridge section before scouring, unit: , is the median particle size of bed sand, unit: , when there is no data, it can be approximated as the average particle size, is the average flow velocity of natural river channels, unit: , is the average flow velocity of the section under the bridge, unit: .

[0069] Further, by arranging the above expressions, we can obtain:

[0070]

[0071] Furthermore, according to the above expression, the height of the backwater in front of the bridge is obtained.

[0072] S12. Determine the reference water level for safe operation.

[0073] The safe operation reference water level is the highest water level to ensure the safe operation of water-related bridges. Multiple water levels should be calculated based on possible water damage incidents that may threaten the safe operation of the bridge during the flood season, and the minimum value should be taken as the safe operation reference water level.

[0074] Wherein, step S12 further includes the following steps:

[0075] S121. Determine the safe operating reference water level considering the drop of superstructure beams.

[0076] In one embodiment, the safe operation reference water level is determined based on the conditions for the bridge superstructure to drop the beams.

[0077] Specifically, the bridge superstructure beam drop meets the following conditions:

[0078]

[0079] in, is the lateral thrust on the bridge superstructure, unit: , is the lateral resistance of the bridge superstructure, unit: The lateral thrust on the bridge superstructure Calculate as follows:

[0080]

[0081] in, Is the impact force of floating objects, unit: , is the dynamic water pressure, unit: , satisfying the following relationship:

[0082]

[0083] in, is the thrust coefficient, which can be taken according to Table 3 based on the different aspect ratios of the superstructure (the ratio of beam height to beam width). For plate beams and rectangular single box beams, the beam width is the bottom width; for variable-width single box beams, the beam width is the average width of the box body; for T beams and multi-box beams, the beam width is the sum of the bottom widths of all T beams or multi-box beams in the transverse direction. is the density of water, unit: , is the acceleration due to gravity, take 9.81 , is the average flow velocity in the river channel, unit: , is the water-blocking area of ​​the superstructure, unit: , satisfying the following relationship:

[0084]

[0085] in, For Liang Chang, is the height of the beam bottom from the riverbed, is the height of the riverbed.

[0086]

[0087] Furthermore, the impact force of the floating object Calculate as follows:

[0088]

[0089] in, is the gravity of floating objects, unit: , should be determined based on the actual situation of floating objects in the river. If there is no survey data, 50 calculate, is the average flow velocity in the river channel, unit: , is the acceleration due to gravity, take 9.81 , is the impact time, unit: , should be estimated based on actual data, and 1s can be taken when there is no actual data.

[0090] Furthermore, the lateral resistance of the bridge superstructure Calculate as follows:

[0091]

[0092] in, is the resistance of the limit device, unit: The value of , varies with the type of limit device and should be determined according to the specific situation. For example, for a concrete limit block, the limit device resistance is the shear bearing capacity of the limit block; is the static friction of the upper structure support, unit: , calculated as follows:

[0093]

[0094] in, is the static friction coefficient of the superstructure bearing, which should be determined based on the actual data of bridge bearings produced by different manufacturers; is the beam weight, unit: , take the value according to the actual situation; is the weight of the passing vehicle, unit: , refer to the highway Class I load standard and reduce the value by 0.8 times. is the buoyancy of the beam, unit: , calculated as follows:

[0095]

[0096] in, is the effective width of the submerged part of the superstructure, unit: , for plate beams and rectangular single box beams, Its bottom width, unit: , for variable width single box girder, is the average width of the submerged box part; for T beams and multi-box beams, The sum of the bottom widths of all T-beams or multi-box beams in its transverse direction, is the height of the beam body submerged in water, unit: ,unit, is the water level under the bridge, unit: , is the unit weight of water, unit: , is the beam length, unit: .

[0097] Furthermore, in order to prevent the occurrence of upper structure beam collapse and water damage, the water level under the bridge is At least the following requirements should be met:

[0098]

[0099] Through trial calculation, there is a critical water level value , making Establishment, that is, the lateral thrust on the bridge superstructure and the lateral resistance of the bridge superstructure The critical water level at this time is It is the safe operating reference water level considering the upper structure beam drop, and is named the first safe operating reference water level.

[0100] S122. Determine the safe operating reference water level that takes into account the displacement of bridge piers caused by dynamic water pressure and impact of floating objects.

[0101] In one embodiment, the safe operation reference water level is determined based on the condition that the bridge pier is deflected due to the dynamic water pressure and the impact of floating objects.

[0102] Specifically, for continuous beam and simply supported beam bridges, the following conditions must be met for the piers to be deflected by hydrodynamic pressure and impacts from floating objects, affecting the structural safety:

[0103]

[0104] in, is the displacement of the top of the pier, unit: , The maximum displacement of the bridge pier allowed during the bridge operation phase, unit: , determined by relevant design standards;

[0105] Furthermore, for continuous beam and simply supported beam bridges, the displacement of the pier top is Calculate as follows:

[0106]

[0107]

[0108] in, The impact force of floating objects on the bridge pier, unit: , is the hydrodynamic pressure on the pier, unit: , is the pier height, unit: , is the pier section stiffness, unit: , is the water level under the bridge, unit: . Calculate as follows:

[0109]

[0110] in, is the water-blocking area of ​​the bridge pier, i.e. the projected area in the direction of water flow, unit: , is the average flow velocity in the river channel, unit: , is the density of water, unit: , is the acceleration due to gravity, take 9.81 , is the pier shape coefficient, and its value is determined according to Table 4.

[0111]

[0112] Furthermore, in order to prevent the bridge piers from being displaced by the dynamic water pressure and the impact of floating objects, the water level under the bridge is At least the following requirements should be met:

[0113]

[0114] Through trial calculation, there is a critical water level value , making , that is, the displacement of the top of the pier and the maximum displacement of the pier allowed during the operation of the bridge are equivalent. The critical water level at this time is It is the safe operating reference water level that takes into account the displacement of bridge piers caused by dynamic water pressure and impact of floating objects, and is named the second safe operating reference water level.

[0115] S123. Determine the safe operating reference water level that takes into account the possibility of collapse of bridge piers due to dynamic water pressure and impact of floating objects.

[0116] In one embodiment, the safe operating reference water level is determined based on the conditions under which the bridge piers collapse due to dynamic water pressure and impact of floating objects.

[0117] Specifically, the collapse of the bridge pier due to the dynamic water pressure and the impact of floating objects satisfies the following conditions:

[0118]

[0119] in, is the maximum bending moment of the pier, unit: , is the design bending bearing capacity of the pier, unit: , calculated based on the pier section geometry and material strength design values.

[0120] Furthermore, for continuous beam and simply supported beam bridges, the maximum bending moment of the pier is determined by the following two formulas:

[0121]

[0122]

[0123] in, and The bending moment calculated by the above two formulas, unit: , The impact force of floating objects on the bridge pier, unit: , is the hydrodynamic pressure on the pier, unit: , is the pier height, unit: , is the water level under the bridge, unit: .

[0124] Further, take and The larger value is taken as the maximum bending moment of the pier .

[0125] Furthermore, for rigid frame bridges, the maximum bending moment of the pier is calculated according to the following formula, and the larger value is taken as the maximum bending moment of the pier:

[0126]

[0127] in, is the pier bending moment, unit: , The distance between the calculated section and the riverbed, in units of: , 、 are the bending moments generated at the bottom of the pier by the impact force of floating objects and the dynamic water pressure, respectively, in units of: , 、 are the reaction forces generated at the bottom of the pier under the impact of floating objects and the hydrodynamic pressure, respectively, in units of: ; 、 、 、 Calculate as follows:

[0128]

[0129]

[0130]

[0131]

[0132] in, The impact force of floating objects on the bridge pier, unit: , is the hydrodynamic pressure on the pier, unit: , is the pier height, unit: , is the water level under the bridge, unit: .

[0133] Further, take The maximum value is taken as the maximum bending moment of the pier .

[0134] Furthermore, in order to prevent the bridge piers from collapsing due to the dynamic water pressure and the impact of floating objects, the water level under the bridge is At least the following requirements should be met:

[0135]

[0136] Through trial calculation, there is a critical water level value , making , that is, the equivalent relationship between the maximum bending moment of the pier and the design bending bearing capacity of the pier holds. It is the safe operating reference water level that takes into account the possibility of collapse of bridge piers due to dynamic water pressure and impact of floating objects, and is named the third safe reference water level.

[0137] S124. Determine the safe operating reference water level taking into account the bridge cone slope protection and the hollowing out of the bridge-road transition section.

[0138] In one embodiment, the safe operation reference water level is determined based on the conditions of the bridge cone slope protection and the hollowing of the bridge-road transition section.

[0139] Specifically, the bridge conical slope protection and the bridge-road transition section hollowing out meet the conditions for seepage to escape from the slope, which can be determined by the geometric position of the seepage line in the slope. The seepage line in the conical slope protection and the bridge-road transition section can be calculated as follows:

[0140]

[0141] in, It is the vertical distance from any point on the seepage line to the bridge cone slope protection and the foot of the bridge-road transition section, unit: , It is the horizontal distance from any point on the seepage line to the seepage escape point, unit: , is a coefficient related to slope material and water level, unit: , The vertical distance between the escape point and the toe of the backwater slope, unit: , is the total seepage length, unit: . and Satisfies the following relationship:

[0142]

[0143] in, The water level of the bridge cone slope protection and the bridge-road transition section facing the water, unit: , It is the horizontal distance from the intersection of the water level line on the upstream side and the slope surface to the toe of the downstream side, unit: , is the slope angle of the water-facing surface, is the slope angle of the backwater side, The water level of the bridge cone slope protection and the bridge-road transition section backwater surface, unit: , Satisfy the following formula:

[0144]

[0145] Furthermore, in order to prevent the occurrence of bridge cone slope protection and bridge-road transition section hollowing incidents, the water level under the bridge At least the following requirements should be met:

[0146]

[0147] Through trial calculation, there is a critical water level value , making Established, that is, the vertical distance between the escape point and the back slope foot is equal to 0. It is the safe operating reference water level that takes into account the bridge cone slope protection and the hollowing out of the bridge-road transition section, and is named the fourth safe operating reference water level.

[0148] S125. Determine the safe operating reference water level considering driving safety.

[0149] In one embodiment, considering the emergency passage demand during flood season and to ensure driving safety, for non-flooded bridges, the safe operation reference water level considering driving safety is calculated as follows:

[0150]

[0151] in, Indicates critical water level, unit: , Indicates the lowest elevation of the bridge beam bottom, unit: , Indicates the clearance safety value between the design flood level and the beam bottom elevation, unit: At this time In order to consider the operating reference water level for driving safety, it is named the fifth safe operating reference water level.

[0152] S126. Determine the overall safe operating benchmark water level.

[0153] In one embodiment, the minimum value among the first safe operation reference water level, the second safe operation reference water level, the third safe operation reference water level, the fourth safe operation reference water level and the fifth safe operation reference water level is determined as the overall safe operation reference water level.

[0154] S13. Determine the maximum historical flood level.

[0155] The historical maximum flood level is the water level of the largest flood in history at the location of the bridge.

[0156] In one embodiment, for areas with hydrological data, the historical maximum flood level is determined based on data provided by the water conservancy department; for areas without hydrological data, the historical maximum flood level is determined based on flood marks left on bridge structures, local chronicles, or recollections of nearby elders.

[0157] S14. Establish a safe water level system for bridges during flood season.

[0158] In one embodiment, a flood season bridge safety water level system is constructed by using the defense warning water level, the safe operation reference water level and the historical maximum flood level.

[0159] S2. Set up flood season bridge safety water level signs based on the flood season bridge safety water level line system.

[0160] In one embodiment, a flood season bridge safety water level sign is designed based on the flood season bridge safety water level system. The flood season bridge safety water level sign, also called flood prevention sign, consists of a scale and graded water level lines, reflecting the water level distance under the bridge, such as Figure 2 shown.

[0161] Furthermore, the design results of the font type, water level scale text height, water level scale width, graded water level width, graded water level text color, background color, sign production material, water level scale accuracy, viewing range requirements, installation location and fixing method of the flood season bridge safety water level sign are obtained. The design results include the characteristics of the flood season bridge safety water level sign. Specifically, they are as follows:

[0162] 1. The font should be the same as that of type B traffic signs; the fonts of the text within the same flood control sign should be unified.

[0163] 2. The height of the water level scale text shall not be less than 5cm, and the height of the graded water level line marking text shall not be less than 7cm.

[0164] 3. The width of the water level scale should be no less than 2 cm, and the width of the graded water level lines should be no less than 10 cm. When flood control signs are installed on bridge piers, the graded water level lines should circle the piers.

[0165] 4. Among the marking texts of the graded water level lines, the marking text of the defense warning water level is dark blue, and the marking abbreviation is "Warning"; the marking text of the safe operation benchmark water level is red, and the marking abbreviation is "Benchmark"; the marking text of the historical maximum flood level is black, and the marking abbreviation is "Historical"; the background color is white.

[0166] 5. Use reflective and anti-fouling paint to paint the surface of stainless steel plates to make identification plates, or directly paint them on the surface of bridge piers and abutments.

[0167] 6. The minimum scale of the water level scale shall not exceed 50cm.

[0168] 7. The observation range is more than 1.0m higher than the higher of the historical maximum flood level and the safe operation benchmark water level, and less than 0.5m lower than the defense warning water level.

[0169] 8. It should be installed in a conspicuous position on the bridge piers, abutments, and bridge head cone slope protection water-related components, and in a position facing the shore for easy observation.

[0170] 9. Use bolts or welding to fix to bridge components, and do not use gluing to fix.

[0171] Furthermore, based on the design results, a flood season bridge safety water level mark is set.

[0172] S3. Based on the flood season bridge safety water level mark, the water depth at the bridge pier is obtained using the Karman vortex street effect and low-concentration ion labeling technology.

[0173] In one embodiment, based on the flood season bridge safety water level mark, the Karman vortex street effect is used to establish a relationship model between the shedding frequency of the Karman vortex street and the water flow velocity at the bridge pier. The relationship model satisfies the following expression:

[0174]

[0175] in, is the shedding frequency of the Karman vortex street, is the Strouhal number, is the width of the bridge pier's water-facing projection, is the water flow velocity at the bridge pier.

[0176] Furthermore, based on the flood season bridge safety water level marker, an environmentally safe slow-release electrolyte layer, including KCl and NaCl, is applied to the pier surface at the graduated water level lines. When the flood season bridge safety water level marker indicates that the water level reaches the graduated water level lines, the slow-release electrolyte layer releases trace ions under the scouring of the water flow.

[0177] Furthermore, low-concentration ion labeling technology is used to label trace ions. Due to the periodic shedding of Karman vortexes, ion clusters carried away by the water flow also pass through a point downstream, maintaining the same periodicity as the Karman vortex shedding. The presence of ion clusters changes the water conductivity at that point downstream.

[0178] Furthermore, a monitoring electrode is installed at a certain point downstream, and the periodic fluctuation of water conductivity is measured by the change of electrical signal intensity, thereby obtaining the shedding frequency of the Karman vortex street.

[0179] Furthermore, the shedding frequency of the Karman vortex street is substituted into the relationship model to obtain the water flow velocity at the bridge pier: .

[0180] Furthermore, the water depth at the bridge piers was calculated by combining the river channel dimension measurements at the bridge site with the following expression:

[0181]

[0182] in, is the riverbed roughness coefficient, is the hydraulic radius. When the width-to-depth ratio of the section is greater than 10, the average water depth can be used instead. When the above conditions are not met, the hydraulic radius This is the wet perimeter of the river channel, which is related to the water depth. is the riverbed gradient, which means that the , which determines the water depth.

[0183] The advantage of this method lies in its use of two methods to monitor water depth. The first is a triggered monitoring method based on graded water levels. When the water level reaches a certain graded water level, the water flowing through the bridge piers generates a Karman vortex street. The vortex street characteristics are sensed by the monitoring electrodes and quickly reflected to the backend, thereby informing the actual water level that it has reached a certain graded water level. The second is a continuous water level monitoring method. Based on the above calculation expression for the flow velocity and water depth at the bridge pier, the water depth is continuously monitored, and the backend can determine the distance between the current water level and a certain graded water level.

[0184] It should be pointed out that this method can monitor the water depth and flow velocity effectively at the same time, which provides important parameters for calculating the stress conditions of the bridge structure under different water levels mentioned above.

[0185] S4. Obtain monitoring results of the water level under the bridge based on the water depth at the bridge pier.

[0186] In one embodiment, based on the water depth obtained in step S3 and in combination with the flood season bridge safety water level mark set in step S2, the monitoring result of the water level under the bridge is obtained.

[0187] Specifically, by monitoring changes in water depth, the distance between the current water level and the "historical", "benchmark" or "warning" graded water level line can be obtained, thereby monitoring changes in water levels and providing guidance for bridge maintenance departments to formulate emergency response measures during flood season.

[0188] S5. Based on the monitoring results, early warning of the water level under the bridge during the flood season is achieved.

[0189] In one embodiment, based on monitoring water level , set three levels of warning thresholds, namely emergency water level threshold , dangerous water level threshold , warning water level threshold .

[0190] Furthermore, water levels will be monitored Compare with the three-level warning thresholds to achieve early warning of bridge water levels during flood season. The details are as follows:

[0191] when When the monitored water level reaches the historical maximum flood level, causing serious damage to the bridge, making it unsafe to operate, the red alarm light flashes and the alarm sounds;

[0192] when When the monitored water level exceeds the safe operation benchmark water level, causing minor damage to the bridge and making it impossible for the bridge to operate safely, the orange warning light will flash and an alarm will sound;

[0193] when When the monitored water level does not exceed the safe operation benchmark water level, but reaches the warning water level, the bridge is almost undamaged and can operate safely. At this time, the water level is abnormal and requires increased attention. The yellow alarm light flashes, but no alarm sound is issued;

[0194] when When the monitored water level is below the warning level, the bridge cannot be damaged and can operate safely. At this time, the water level is normal, the alarm light does not flash, and no alarm sound is issued.

[0195] See Figure 3 , Figure 3 The following is a schematic diagram of the structure of a flood season bridge water level monitoring and early warning system according to an embodiment of the present invention. The system includes an input device, a processor, an output device, and a memory, wherein the input device, the processor, the output device, and the memory are interconnected. The memory is used to store a computer program, which includes program instructions. The processor is configured to invoke the program instructions. The system utilizes the flood season bridge water level monitoring and early warning method described above.

[0196] In this embodiment, the input device includes a Karman vortex flow velocity sensor, a low-concentration ion marker detector, a riverbed cross-section scanner, a water level gauge, an environmental monitor, and a user input interface.

[0197] Specifically, the Karman vortex flow velocity sensor is installed on the water-facing side of the bridge pier to detect the vortex shedding frequency; the low-concentration ion marker detector is deployed in the waters around the bridge pier to enhance the vortex signal recognition capability; the riverbed cross-section scanner is used to measure river parameters, including river channel width and river beach area; the water level gauge has graded water level scales with a fluorescent photoluminescent coating for manual review; the environmental monitor collects auxiliary data, including rainfall and water sediment content; and the user input interface is used to input bridge-related parameters.

[0198] The processor includes an edge computing unit, a core computing module and a risk prediction module.

[0199] Specifically, the edge computing unit is deployed at the bridge site to perform real-time data preprocessing; the core computing module runs the water level analysis algorithm; and the risk prediction module predicts the water level change trend based on historical data training.

[0200] The output device includes an audible and visual alarm device, a remote monitoring platform and an electronic water level display screen.

[0201] Specifically, the sound and light alarm device is installed at both ends of the bridge, and issues different alarms according to the warning level; the remote monitoring platform is transmitted to the management center via 4G / 5G and supports PC / mobile viewing; the electronic water level display screen at the bridge head displays the real-time water level and safety status.

[0202] The memory includes a local storage unit and a cloud database.

[0203] Specifically, the local storage unit is used to cache recent monitoring data; the cloud database is used to store long-term hydrological data, warning events and model parameters.

[0204] In summary, the present invention aims at the possible bridge water damage incidents that may occur during the flood season and proposes a flood season bridge water level monitoring and early warning method. By constructing a safe water level line system and setting water level signs, the water level conditions under the bridge are clearly and prominently displayed during the flood season; by color-coding and grading the water level lines and adding warning water level prompt signs, a systematic and standardized water level visual recognition system is formed, which effectively makes up for the functional limitations of existing water level signs and significantly improves the accuracy of bridge safety monitoring during the flood season and the timeliness of emergency response; by using the Karman vortex street effect and low-concentration ion labeling technology to monitor water depth, a real-time early warning of water level exceeding the limit is achieved, which provides a quantitative basis for bridge safety assessment and emergency closure.

[0205] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A flood season bridge water level monitoring and early warning method, characterized in that: The method comprises the following steps: Establish a bridge safety water level system during flood season, which includes the historical maximum flood level, the safe operation benchmark water level and the defense warning water level; According to the above mentioned bridge safety water level system during flood season, set up bridge safety water level signs during flood season; Based on the bridge safety water level mark during flood season, the water depth at the bridge pier is obtained by using the Karman vortex street effect and low-concentration ion labeling technology, including: Based on the flood season bridge safety water level mark, the Karman vortex street effect is used to establish a relationship model between the shedding frequency of the Karman vortex street and the water flow velocity at the bridge pier. The relationship model satisfies the following expression: , in, is the shedding frequency of the Karman vortex street, is the Strouhal number, is the width of the bridge pier's water-facing projection, is the water velocity at the bridge pier; The shedding frequency of the Karman vortex street was obtained using low-concentration ion labeling technology; Obtaining the flow velocity at the bridge pier according to the relationship model and the shedding frequency of the Karman vortex street; The relationship between the flow rate and the hydraulic radius is established as follows: , in, is the water velocity at the bridge pier, is the hydraulic radius, is the riverbed roughness coefficient, is the riverbed gradient; Based on the above relationship and in combination with the river channel dimension measurement results at the bridge site, the water depth at the bridge pier is obtained; Obtaining monitoring results of the water level under the bridge according to the water depth at the bridge pier; Through the monitoring results, risk warning of water level under the bridge during flood season can be achieved.

2. A flood season bridge water level monitoring and early warning method according to claim 1, characterized in that: The construction of the flood season bridge safety water level system includes: Determine the defense warning water level; Determine the reference water level for safe operation; Determine the historical maximum flood level; A flood season bridge safety water level system is constructed through the defense warning water level, the safe operation benchmark water level and the historical maximum flood level.

3. A flood season bridge water level monitoring and early warning method according to claim 2, characterized in that: Determining the defense warning water level includes: Determine and verify flood flow; Using the verified flood flow, a calculation expression for the flow at the riverbed section at the bridge location is established; According to the calculation expression, the hydraulic radius of the river channel and the riverbank is obtained; Determining the flood level using the hydraulic radius; Based on the flood water level, a calculation model for the height of the backwater in front of the bridge is established; According to the calculation model, the height of the backwater in front of the bridge is obtained; The defense warning water level is determined by the flood water level and the height of the water in front of the bridge.

4. A flood season bridge water level monitoring and early warning method according to claim 3, characterized in that: The calculation expression of the flow at the riverbed section at the bridge location is as follows: , in, To calculate flood flow, 、 are the water-flowing areas of the river channel and riverbank respectively. 、 are the riverbed roughness coefficients of the river channel and riverbank, 、 are the hydraulic radius of the river channel, is the riverbed gradient; the calculation model of the backwater height in front of the bridge satisfies the following expression: , in, is the maximum water level in front of the bridge, is the average flow velocity of the natural section in front of the bridge, is the coefficient related to the pier shape, is the acceleration due to gravity, is the average flow velocity under the bridge section before scouring, is the median particle size of bed sand, is the average flow velocity of a natural river channel.

5. The method for monitoring and warning bridge water levels during flood season according to claim 2, characterized in that: Determining the safe operation reference water level includes: Determine the safe operating reference water level considering the dropped beams of the bridge superstructure and obtain the first safe operating reference water level; Determine the safe operating reference water level that takes into account the displacement of the bridge piers due to dynamic water pressure and impact of floating objects, and obtain the second safe operating reference water level; Determine the safe operating reference water level that takes into account the possibility of collapse of bridge piers due to dynamic water pressure and impact of floating objects, and obtain the third safe operating reference water level; Determine the safe operating reference water level taking into account the bridge cone slope protection and the hollowing of the bridge-road transition section, and obtain the fourth safe operating reference water level; Determine the safe operation reference water level considering driving safety and obtain the fifth safe operation reference water level; The minimum value among the first safe operation reference water level, the second safe operation reference water level, the third safe operation reference water level, the fourth safe operation reference water level and the fifth safe operation reference water level is determined as the overall safe operation reference water level.

6. A flood season bridge water level monitoring and early warning method according to claim 5, characterized in that: Determining the safe operation reference water level considering the bridge superstructure beam drop includes: establishing a beam drop prevention critical water level model, and determining the safe operation reference water level considering the bridge superstructure beam drop based on the beam drop prevention critical water level model; Determining the safe operating reference water level that takes into account the displacement of the bridge piers due to the dynamic water pressure and the impact of floating objects includes: establishing a critical water level model for the bridge piers to resist displacement, and determining the safe operating reference water level that takes into account the displacement of the bridge piers due to the dynamic water pressure and the impact of floating objects based on the critical water level model for the bridge piers to resist displacement; Determining the safe operating reference water level considering the collapse of the bridge pier due to dynamic water pressure and impact of floating objects includes: establishing a critical water level model for bridge pier anti-collapse, and determining the safe operating reference water level considering the collapse of the bridge pier due to dynamic water pressure and impact of floating objects based on the critical water level model for bridge pier anti-collapse; Determining the safe operating reference water level taking into account the bridge tapered slope protection and the hollowing of the bridge-road transition section includes: establishing a bridge-area water-soil coupled anti-erosion critical water level model, and determining the safe operating reference water level taking into account the bridge tapered slope protection and the hollowing of the bridge-road transition section based on the bridge-area water-soil coupled anti-erosion critical water level model; The determining of the safe operation reference water level considering driving safety includes: establishing a driving safety critical water level model, and determining the safe operation reference water level considering driving safety based on the driving safety critical water level model.

7. A flood season bridge water level monitoring and early warning method according to claim 6, characterized in that: The critical water level model of the anti-fall beam satisfies the following relationship: , in, Indicates that the critical water level is The lateral thrust on the bridge superstructure is Indicates that the critical water level is The lateral resistance of the bridge superstructure is: The critical water level model of the pier anti-deflection satisfies the following relationship: , in, The critical water level is The displacement of the top of the pier is is the maximum displacement of the pier allowed during the bridge operation phase; the critical water level model for pier collapse resistance satisfies the following relationship: , in, The critical water level is The maximum bending moment of the bridge pier is represents the design bending bearing capacity of the bridge pier; the bridge area water-soil coupled anti-corrosion critical water level model satisfies the following relationship: , in, The critical water level is The vertical distance between the escape point and the toe of the back water surface; the critical water level model for driving safety satisfies the following relationship: , in, Indicates the critical water level, Indicates the lowest elevation of the bridge beam bottom. Indicates the clearance safety value between the design flood level and the beam bottom elevation.

8. The method for monitoring and early warning of bridge water levels during flood season according to claim 1, characterized in that: The setting of flood season bridge safety water level markings according to the flood season bridge safety water level system includes: Design a flood season bridge safety water level sign based on the flood season bridge safety water level system, and obtain design results for the flood season bridge safety water level sign's font type, water level scale text height, water level scale width, graded water level line width, graded water level line text color, background color, sign production material, water level scale accuracy, viewing range requirements, installation location, and fixing method; According to the design results, the flood season bridge safety water level mark is set.

9. A flood season bridge water level monitoring and early warning system, the system using the flood season bridge water level monitoring and early warning method according to any one of claims 1 to 8, characterized in that: The system includes an input device, a processor, an output device and a memory, wherein the input device, the processor, the output device and the memory are connected to each other, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions.

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