Collision risk probability calculation method and system based on new anti-collision specification

Abstract

The invention relates to the field of bridge safety management, in particular to a collision risk probability calculation method and system based on a new anti-collision specification. The collision risk probability calculation method based on the new anti-collision specification comprises the following steps: S1, inputting calculation parameters; s2, establishing a channel model, and calculating coordinates, a channel bending correction coefficient and a seasonal water level correction term; s3, calculating a collision risk probability based on a probability distribution model; and S4, outputting a result. The collision risk probability calculation system is used for realizing the collision risk probability calculation method and comprises an input module, a model selection module, a data processing module, a probability calculation module and a result output module. The invention specifically provides a probability distribution function about ships and water levels and a multi-dimensional integral function for calculating collision risk probability; correction terms related to the navigation channel and the environment are added into the probability distribution function, so that the modeling accuracy is improved; and multi-dimensional integral is used for coupling multi-source parameters, so that the calculation precision of the collision risk probability is improved.

Description

Technical Field

[0001] The present invention relates to the field of bridge safety management, and particularly to a method and system for calculating the probability of impact risk based on a new anti-collision specification. Background Art

[0002] In 2020, the Ministry of Transport introduced a new specification for bridge anti-collision, "Code for Anti-collision Design of Highway Bridges" (JTGT 3360-02-2020). When calculating the ship collision risk, this specification no longer uses the empirical formula of the previous specification, but uses a new probability model to calculate the risk of ships hitting bridges. According to the technical requirements of the new specification, it is necessary to calculate the annual impact frequency results of each underwater pier of the bridge being hit by ships, so as to calculate the probability of bridge collapse according to the specification later.

[0003] The current new specification cannot simply apply the empirical formula to obtain the impact risk of the bridge being hit by ships. It is necessary to establish a new calculation method to meet the requirements of the new specification. It is necessary to select the corresponding probability model formula according to the actual waterway conditions and obtain the probability of ship impact on the bridge through integration. The original analysis method no longer meets the requirements of the new specification.

[0004] The new specification only proposes that the relevant distribution function is a probability function, and there is no specific calculation method for the impact risk of ships; at the same time, there is also a lack of correction terms according to waterways and seasons. Summary of the Invention

[0005] To solve the technical problems that the existing technology lacks a calculation method for the impact risk of ships that meets the requirements of the new specification and cannot correct the influence of waterway and season parameters, the present invention proposes a method and system for calculating the probability of impact risk based on a new anti-collision specification, specifically proposing a probability distribution function for ships and water levels and a multi-dimensional integral function for calculating the probability of collision risk; correction terms related to waterways and the environment are added to the probability distribution function to improve the modeling accuracy, and multi-source parameters are coupled using multi-dimensional integration to improve the calculation accuracy of the impact risk probability.

[0006] The technical solution of the present invention is as follows:

[0007] A method for calculating the probability of impact risk based on a new anti-collision specification, comprising:

[0008] S1, input calculation parameters, including: bridge parameters, ship parameters, waterway parameters, environmental parameters;

[0009] The bridge parameters include: pier position, safety threshold x 安全 , maximum stopping distance d max ;

[0010] The ship parameters include: tonnage T, ship length L, ship width, ship speed v, braking efficiency η, and navigable flow rate;

[0011] The channel parameters include: channel type, transverse flow velocity V of the channel 流 , and radius of curvature R; The channel types include: straight channel, curved channel, and diagonal channel;

[0012] The environmental parameters include: critical water level h c , historical water level probability p, annual average water level p annual , and annual average water level p in a specific season season .

[0013] S2. Establish a channel model: Determine the channel type according to the channel parameters and establish a channel model, calculate the coordinates μ of the channel center line x , and channel bending correction coefficient α, and calculate the seasonal water level correction term Δp according to the environmental parameters;

[0014] According to the natural conditions of the water area and the angle between the ship channel center line and the bridge axis, the channel can be divided into a straight channel, a diagonal straight channel, and a curved channel; Establish a polyline model for the curved channel and the diagonal channel to describe the coordinates of the channel, the coordinates of the riverbed topography, and the coordinates of the bridge piers; Establish a simplified straight line model for the straight channel, and the straight line model is a polyline model with only one line segment.

[0015] The calculation formula for the channel bending correction coefficient α is:

[0016]

[0017] In the formula, R0 is the reference bending radius, taking R0 = 5L; k is the curvature sensitivity coefficient, obtained through actual measurement or statistical calibration, taking k = 0.5 - 2.0;

[0018] The calculation formula for the seasonal water level correction term Δp is:

[0019]

[0020] In the formula, σ is the sensitivity parameter, which reflects the influence degree of the water level on the impact probability through data fitting of historical data, taking 0.5 ≤ σ ≤ 2.

[0021] S3. Calculate the collision risk probability based on the probability distribution model: Establish a probability distribution model for the ship and water level based on the distribution function. Input the value ranges of the water level h, yaw angle θ, lateral yaw distance x, and stopping distance d, and integrate the probability distribution model within the input value ranges to calculate the collision risk probability. The probability distribution model is the product of the lateral distribution function of the yawing ship, the yaw angle distribution function of the ship, the water level distribution function in the bridge area, and the stopping distance distribution function.

[0022] The lateral distribution function of the yawing ship is established using a modified normal distribution function and corrected using the channel curvature correction coefficient α.

[0023] The yaw angle distribution function of the ship is established using the extreme value type I distribution function.

[0024] The water level distribution function in the bridge area is established using a two-piecewise function and corrected using the seasonal water level correction term Δp.

[0025] The stopping distance distribution function is established using a truncated normal distribution function.

[0026] The construction method of the probability distribution model is as follows:

[0027] S31. Based on the ship length L and the coordinates of the center line of the channel μ x , establish the lateral distribution function f X (x):

[0028]

[0029] S32. Based on the tonnage T, establish the yaw angle distribution function f θ (θ):

[0030]

[0031] where β = 0.1T + 2; μ θ is the average yaw angle, that is, the average of the yaw angles of the ship passing through the bridge position of this channel in the past three years;

[0032] S33. Based on the critical water level h c , the historical water level probability p, and the seasonal water level correction term Δp, establish the water level distribution function f H (h):

[0033]

[0034] S34. Based on the ship speed v and the braking efficiency η, establish the stopping distance distribution function f D (d):

[0035]

[0036] Among them, σ d is the standard deviation of the stopping distance obtained from historical statistical data; g is the acceleration due to gravity, I is the indicator function, and d max is the maximum stopping distance;

[0037] S35. According to the value ranges of the water level h, yaw angle θ, lateral yaw distance x, and stopping distance d, the probability distribution model is integrated to calculate the collision risk probability P 撞击 :

[0038]

[0039] Among them, δ(x, θ, h, d) is the integration condition parameter, which takes 1 when the integration conditions are met and 0 otherwise.

[0040] The integration conditions are simultaneously satisfied as follows:

[0041] The lateral yaw distance x exceeds the safety threshold x 安全 ;

[0042] The yaw angle θ causes the ship's heading to intersect with the pier;

[0043] The water level h meets the navigation conditions, i.e., h ≥ h c ;

[0044] The stopping distance d is less than the warning distance d in front of the bridge 警戒 .

[0045] S4. Result output: According to the collision risk probability, calculate and output the annual impact frequency result and risk level assessment.

[0046] An impact risk probability calculation system based on a new anti-collision specification, which is used to implement the impact risk probability calculation method based on the new anti-collision specification, includes: an input module, a model selection module, a data processing module, a probability calculation module, and a result output module;

[0047] The input module is used to input the calculation parameters; the calculation parameters include: bridge parameters, ship parameters, waterway parameters, and environmental parameters;

[0048] The model selection module determines the waterway model type based on the calculation parameters;

[0049] The data processing module is used to calculate the waterway model, waterway correction coefficient, and seasonal water level correction term based on the calculation parameters and the waterway model type;

[0050] The probability calculation module establishes a probability distribution model of the ship and water level in the waterway model based on the calculation parameters, and performs integral calculation on the probability distribution model to obtain the collision risk probability P. 撞击 The probability distribution model is: the product of the lateral distribution function of the yawing ship, the yaw angle distribution function of the ship, the water level distribution function in the bridge area, and the stopping distance distribution function.

[0051] The result output module is based on the collision risk probability prediction annual impact frequency result and risk level assessment result of the probability calculation module.

[0052] The present invention proposes a method and system for calculating the impact risk probability based on a new anti-collision specification, specifically proposes a probability distribution function of the ship and water level and a multi-dimensional integral function for calculating the collision risk probability to meet the requirements of the new specification for the calculation method of the impact risk of the ship; a correction term related to the waterway and environment is added to the probability distribution function, which respectively improves the accuracy of modeling for waterways with different curvature radii and different seasons; multi-source parameters are coupled using multi-dimensional integration, and multiple waterway and ship parameters are used to comprehensively calculate the impact risk probability, improving the calculation accuracy of the impact risk probability. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic flow chart of a method for calculating the impact risk probability based on a new anti-collision specification.

[0054] Figure 2 It is a schematic diagram of a system for calculating the impact risk probability based on a new anti-collision specification.

[0055] Figure 3 It is a schematic diagram of a multi-folded waterway model.

[0056] Figure 4 It is a schematic diagram of the lateral distribution of the yawing ship.

[0057] Figure 5 It is a schematic diagram of the yaw angle distribution function of the ship.

[0058] Figure 6 It is a schematic diagram of the stopping distance distribution function. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0060] A method for calculating the impact risk probability based on a new anti-collision specification, as Figure 1 shown, includes:

[0061] S1, input calculation parameters, including: bridge parameters, ship parameters, waterway parameters, and environmental parameters;

[0062] The bridge parameters include: pier position, safety threshold x 安全 , maximum ship stopping distance d max ;

[0063] The ship parameters include: tonnage T, ship length L, ship width, ship speed v, braking efficiency η, navigation flow;

[0064] The channel parameters include: channel type, lateral channel flow velocity V 流 , radius of curvature R; The channel types include: straight channel, curved channel, diagonal channel;

[0065] The environmental parameters include: critical water level h c , historical water level probability p, annual average water level p annual , annual average water level p in a specific season season .

[0066] S2. Establish a channel model: Determine the channel type according to the channel parameters and establish a channel model, calculate the coordinates μ of the channel center line x , channel bending correction coefficient α, and calculate the seasonal water level correction term Δp according to the environmental parameters;

[0067] According to the definition in the Code for Anti-collision Design of Highway Bridges, according to the natural conditions of the water area and the angle between the ship channel center line and the bridge axis, the channel can be divided into three situations: straight channel, oblique straight channel and curved channel. Establish a multi-segment line model for the curved channel and the diagonal channel; establish a simplified straight line model for the straight channel, and the straight line model is a multi-segment line model with only one segment. If the curve channel center line is approximated by a multi-segment line, the above three channels can be unified under a mathematical model, that is, the multi-segment line channel model, as Figure 3 shown. Use the overall coordinate system O-X-Y to describe the channel coordinates, the coordinates of the riverbed topography, the pier coordinates, etc., and its coordinate origin can be determined according to the convenience of data description. For the convenience of calculation, several local coordinate systems need to be established. Denote the intersection point of two adjacent multi-segment lines of the channel center line as O l , then the local coordinate system of the l-th segment of the channel is O l –x l –y l , the x-axis of this local coordinate system points from O l to O l+1 , and the y-axis of the local coordinate system is determined by the right-hand screw rule.

[0068] The calculation formula for the channel bending correction coefficient α is:

[0069]

[0070] Wherein, R0 is the reference bending radius, and R0 = 5L, where L is the ship length; R is the curvature radius of the waterway; k is the curvature sensitivity coefficient, which needs to be calibrated through actual measurement or statistics, and generally k = 0.5 - 2.0; V 流 is the lateral flow velocity of the waterway;

[0071] The calculation formula for the seasonal water level correction term Δp is as follows:

[0072]

[0073] Wherein, p annual is the annual average water level over the years; p season is the annual average water level in a specific season; σ is the sensitivity parameter, which reflects the influence degree of the water level on the impact probability through data fitting of historical data, and usually 0.5 ≤ σ ≤ 2.

[0074] S3. Calculate the collision risk probability based on the probability distribution model: Establish a probability distribution model for the ship and the water level based on the distribution function, input the value ranges of the water level h, the yaw angle θ, the lateral yaw distance x, and the stopping distance d, and integrate the probability distribution model within the input value ranges to calculate the collision risk probability; the probability distribution model is: the product of the lateral distribution function of the yawing ship, the yaw angle distribution function of the ship, the water level distribution function of the bridge area, and the stopping distance distribution function.

[0075] The lateral distribution function of the yawing ship is established using the modified normal distribution function and corrected using the waterway bending correction coefficient α;

[0076] The yaw angle distribution function of the ship is established using the extreme value type I distribution function;

[0077] The water level distribution function of the bridge area is established using a binary piecewise function and corrected using the seasonal water level correction term Δp;

[0078] The stopping distance distribution function is established using a truncated normal distribution function.

[0079] The lateral distribution function of the yawing ship in the bridge area waterway, the yaw angle distribution function of the ship, the water level distribution function, and the stopping distance distribution function should consider the boundedness of their values. Considering the lateral distribution function of the yawing ship in the waterway, the yaw angle distribution function of the ship, the water level distribution function, and the stopping distance distribution function should consider the boundedness of the range of their independent variables.

[0080] S31. As Figure 4 shown, using the modified normal distribution function, based on the ship length L and the coordinate μ x of the waterway center line, establish the lateral distribution function f X (x) of the yawing ship:

[0081]

[0082] Normally, the lateral distribution function of a yawing ship is generally a normal distribution function. When there is no actual data, the mean of the normal distribution should be the center line of the one-way channel, and the standard deviation should be 1 times the ship length.

[0083] S32, as Figure 5 shown, adopt the extreme value type I distribution function, and establish the ship yaw angle distribution function f θ (θ):

[0084]

[0085] where μ θ is the average yaw angle, which is obtained from AIS data and is the average value of the yaw angles of ships passing through the bridge position of this channel in the past three years. The default value of the average yaw angle μ θ is 0.

[0086] When comparing the yaw angle distribution function with the actual data, more types of distribution functions will be selected, including normal distribution, lognormal distribution, and extreme value type I normal distribution.

[0087] S33, adopt a binary piecewise function, and establish the bridge area water level distribution function f c according to the critical water level h H (h):

[0088]

[0089] For ship navigation, the bridge water level distribution function has only two results: reachable and unreachable. This function is equivalent to reachability analysis.

[0090] S34, as Figure 6 shown, adopt a truncated normal distribution function, and establish the stopping distance distribution function f D (d):

[0091]

[0092] where σ d is the standard deviation of the historical stopping distance, which is a parameter related to the ship length L obtained from historical statistical data; g is the acceleration due to gravity, and I is the indicator function.

[0093] The stopping distance distribution function mainly follows the normal distribution function, which is equivalent to the yaw probability in the AASHTO specification.

[0094] S35. Obtain the risk probability P by inputting the value ranges of the input water level h, yaw angle θ, ship's lateral coordinate x, and stopping distance d. 撞击 :

[0095]

[0096] Among them, δ(x, θ, h, d) is the integral condition parameter, which takes 1 when the integral condition is satisfied, and 0 otherwise.

[0097] The integral condition is that all of the following are satisfied simultaneously:

[0098] The lateral yaw distance x exceeds the safety threshold x 安全 ;

[0099] The yaw angle θ causes the ship's course to intersect with the bridge pier;

[0100] The water level h meets the navigation conditions, that is, h ≥ h c ;

[0101] The stopping distance d is less than the warning distance d in front of the bridge 警戒 .

[0102] By using multi-dimensional integration to couple multi-source parameters, the accuracy of the calculation is improved.

[0103] S4. Result output: According to the collision risk probability P 撞击 , calculate and output the annual impact frequency result and the risk level assessment.

[0104] The annual impact frequency result is the relationship between the impact frequency in the time unit of a year and the ship length, and is calculated based on the collision risk probability and the annual navigation voyages of different ship lengths.

[0105] Based on the risk level assessment criteria in the specification, obtain the risk level assessment result according to the annual impact frequency result.

[0106] An impact risk probability calculation system based on a new anti-collision specification, as Figure 2 shown, for implementing the impact risk probability calculation method, including: an input module, a model selection module, a data processing module, a probability calculation module, and a result output module.

[0107] The input module is used to input the calculation parameters; the calculation parameters include: bridge parameters, ship parameters, waterway parameters, and environmental parameters;

[0108] The model selection module determines the waterway model type based on the calculation parameters;

[0109] The data processing module is used to calculate the waterway model, the waterway correction coefficient, and the seasonal water level correction term based on the calculation parameters and the waterway model type;

[0110] The probability calculation module establishes a probability distribution model regarding the ship and water level in the waterway model based on the calculation parameters, and performs integral calculation on the probability distribution model to obtain the collision risk probability P. 撞击 ; The probability distribution model is: the continuous product of the lateral distribution function of the yawing ship, the distribution function of the ship's yaw angle, the distribution function of the water level in the bridge area, and the distribution function of the stopping distance.

[0111] The result output module is based on the collision risk probability prediction annual impact frequency result and the risk level assessment result of the probability calculation module.

[0112] It should be noted that the above specific implementation manners can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way. Therefore, although this specification has described the present invention in detail with reference to the drawings and embodiments, those skilled in the art should understand that the present invention can still be modified or equivalently replaced. In short, all technical solutions and their improvements that do not depart from the spirit and scope of the present invention should be covered by the protection scope of the patent of the present invention.

Claims

1. A method for calculating the probability of impact risk based on a new anti-collision specification, characterized in that, Including: S1. Input calculation parameters, including: bridge parameters, ship parameters, waterway parameters, environmental parameters; S2. Establish a waterway model: Determine the waterway type according to the waterway parameters and establish a waterway model, and calculate the coordinates μ of the waterway centerline x , the waterway bending correction coefficient α, and calculate the seasonal water level correction term Δp according to the environmental parameters; S3. Calculate the collision risk probability based on the probability distribution model: establish a probability distribution model about the ship and water level based on the distribution function, input the value ranges of water level h, yaw angle θ, lateral yaw distance x, and stopping distance d, and integrate the probability distribution model within the input value ranges to calculate the collision risk probability; the probability distribution model is: the product of the lateral distribution function of the yawing ship, the yaw angle distribution function of the ship, the water level distribution function in the bridge area, and the stopping distance distribution function; S4. Result output: Calculate and output the annual impact frequency result and risk level assessment according to the collision risk probability.

2. The method for calculating the impact risk probability based on the new anti-collision specification according to claim 1, characterized in that, In S1, the bridge parameters include: pier position, safety threshold x 安全 , maximum ship stopping distance d max ; The ship parameters include: tonnage T, ship length L, ship width, ship speed v, braking efficiency η, navigation flow; The channel parameters include: channel type, transverse channel velocity V 流 , and radius of curvature R; The channel types include: straight channel, curved channel, and diagonal channel; The environmental parameters include: critical water level h c , historical water level probability p, annual average water level p annual , annual average water level p in a specific season season .

3. The impact risk probability calculation method based on the new anti-collision specification according to claim 1, wherein, In S2, according to the natural conditions of the water area and the angle between the ship channel center line and the bridge axis, the waterway can be divided into a straight waterway, an inclined straight waterway, and a curved waterway; establish a polyline model for the curved waterway and the inclined waterway to describe the coordinates of the waterway, the coordinates of the riverbed terrain, and the coordinates of the bridge piers; establish a simplified straight line model for the straight waterway, and the straight line model is a polyline model with only one line segment.

4. A method for calculating the probability of impact risk based on a new anti-collision specification according to claim 1, characterized in that, The calculation formula for the waterway bending correction coefficient α is: In the formula, R0 is the reference bending radius, taking R0 = 5L, where L is the ship length; k is the curvature sensitivity coefficient, obtained through actual measurement or statistical calibration, taking k = 0.5 - 2.0; v is the ship speed; The calculation formula for the seasonal water level correction term Δp is: In the formula, σ is the sensitivity parameter, which reflects the influence degree of water level on the impact probability through data fitting of historical data, and 0.5 ≤ σ ≤ 2, p annual is the annual average water level, p season is the annual average water level in the specific season.

5. A method for calculating the probability of impact risk based on a new anti-collision specification according to claim 1, wherein In S3, The lateral distribution function of the yawing ship is established using a modified normal distribution function and corrected using the waterway bending correction coefficient α; The yaw angle distribution function of the ship is established using the extreme value type I distribution function; The water level distribution function in the bridge area is established using a binary piecewise function and corrected using the seasonal water level correction term Δp; The stopping distance distribution function is established using a truncated normal distribution function.

6. A method for calculating the probability of impact risk based on a new anti-collision specification according to claim 1 or 5, characterized in that In S3, the construction method of the probability distribution model is: S31. Based on the ship length L and the coordinates μ of the center line of the waterway x , establish the lateral distribution function f X (x) of the yawing ship: S32. Establish a ship yaw angle distribution function f θ (θ) according to the tonnage T: where β = 0.1T + 2; μ θ is the average yaw angle, i.e., the average of the yaw angles of the ship passing through the bridge position of this waterway in the past three years; S33. Based on the critical water level h c , the historical water level probability p, and the seasonal water level correction term Δp, establish the water level distribution function f H (h): S34. Establish a stopping distance distribution function f D (d) according to the ship speed v and the braking efficiency η Among them, σ d is the standard deviation of the stopping distance obtained from historical statistical data; g is the acceleration due to gravity, I is the indicator function, and d max is the maximum stopping distance; S35. Integrate the probability distribution model according to the value ranges of the water level h, yaw angle θ, lateral yaw distance x, and stopping distance d to obtain the collision risk probability P 撞击 : Among them, δ(x, θ, h, d) is the integral condition parameter, taking 1 when the integral condition is satisfied, otherwise taking 0.

7. A method for calculating the impact risk probability based on a new anti-collision specification according to claim 6, characterized in that, In S35, the integral condition is simultaneously satisfied: The lateral yaw distance x exceeds the safety threshold x 安全 ; The yaw angle θ causes the ship's course to intersect with the bridge pier; The water level h meets the navigation conditions, i.e., h≥h c ; The stopping distance d is less than the warning distance d in front of the bridge 警戒 .

8. A collision risk probability calculation system based on a new anti-collision specification for the method according to any one of claims 1-7, characterized in that Including: Input module, model selection module, data processing module, probability calculation module, result output module; The input module is used to input the calculation parameters; The calculation parameters include: bridge parameters, ship parameters, waterway parameters, environmental parameters; The model selection module determines the waterway model type based on the calculation parameters; The data processing module is used to calculate the waterway model, waterway correction coefficient, and seasonal water level correction term based on the calculation parameters and the waterway model type; The probability calculation module establishes a probability distribution model of the ship and water level in the waterway model based on the calculation parameters, and performs integral calculation on the probability distribution model to obtain the collision risk probability P 撞击 ; the probability distribution model is: the continuous product of the lateral distribution function of the yawing ship, the distribution function of the ship's yaw angle, the distribution function of the water level in the bridge area, and the distribution function of the stopping distance; The result output module predicts the annual impact frequency result and risk level assessment result based on the collision risk probability of the probability calculation module.

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