A Canal Water Depth Calculation Method Optimized Based on the Sinking Amount of Ship Navigation

Abstract

The present invention discloses a method for calculating the water depth of a canal waterway optimized based on the sinking amount of a ship during navigation, belonging to the technical field of water transportation engineering. This method first determines the ship parameters and waterway parameters used for calculating the sinking amount of the ship, and calculates the sinking amount at the stern of the ship using the ship sinking amount calculation formula; subsequently, the parameters are updated based on the calculation results and iterative calculations are performed until the calculation error is less than the set value, and finally the corrected calculated water depth of the waterway is obtained. This method also combines the inland waterway navigation standards to calculate the standard water depth and the minimum water depth of the waterway, and finally takes the maximum value among the three calculation results as the design value of the waterway water depth. By introducing a ship dynamic sinking correction factor, this method fully considers the non-uniformity during the ship sinking process, improves the calculation accuracy, provides a scientific basis for waterway maintenance, dredging planning and the formulation of navigation standards, enhances the accuracy and adaptability of canal waterway management, and at the same time enhances the navigation safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of water transportation engineering, and particularly relates to a method for calculating the water depth of a canal waterway optimized based on the sinking amount of a ship during navigation. Background Technique

[0002] In the design of inland waterway projects, the water depth of the waterway is one of the key parameters of the waterway scale. The calculation of the canal water depth plays a crucial role in waterway design and subsequent operation. Reasonable water depth design directly affects the navigation ability of ships, ensuring the safe and efficient passage of ships under various hydrological conditions. Insufficient water depth may cause ships to run aground or limit the load, while excessive depth increases project costs and maintenance difficulties. Accurate water depth calculation is not only a key link in waterway design but also an important foundation for ensuring the long-term stable operation of the canal.

[0003] At present, the method for determining the canal water depth mainly relies on the "Inland Navigation Standards" (GB 50139-2014) and the "Waterway Engineering Handbook", but this method has many deficiencies in the calculation of the canal water depth. First of all, the value of the additional water depth determined by the current standard mainly considers the ship's scale, but insufficient consideration is given to the influence of hydrodynamic factors such as the bottom sediment of the riverbed, flow velocity, and slope. This calculation method fails to comprehensively reflect the actual situation of ship navigation under different hydrological conditions, making the water depth calculation result may deviate under certain complex conditions. Especially for canals, canals are restricted waterways, and the sinking amount of ships during navigation is greater than that of natural waterways, and the impact on the water depth of the waterway is more significant than that of non-restricted waterways.

[0004] According to existing research experience, the value of the ship's sinking amount provided by the current standard is often on the low side. For example, the "Waterway Engineering Handbook" recommends a sinking amount of 0.25m for 3,000-ton ships, while relevant experimental studies have shown that when sailing in a rectangular cross-section channel, the maximum sinking amount at the stern of the ship increases significantly with the increase of the ship speed. When the ship speed reaches 1.92m / s, some experimental results show that the maximum sinking amount at the stern of the ship has exceeded 0.25m, and when the ship speed increases to 3.34m / s, the maximum sinking amount at the stern of the ship is generally greater than 0.25m, and the highest can even reach 0.39m. Thus, relying solely on the current standard to calculate the canal water depth may result in a low calculated value when the ship speed is relatively high, thereby affecting the navigation safety of the waterway.

[0005] At present, although there are some commonly used domestic and foreign calculation methods for the sinking amount of shallow-water ships, mainly including the Barrass formula, Huuska-Guliev formula, Yoshimura formula, Eryuzlu formula, Millward90 formula, etc. However, there are many problems and deficiencies in the applicability of these commonly used calculation formulas in the canal waterway environment, which are mainly reflected in the following aspects:

[0006] First, existing calculation methods generally assume that a ship sinks parallelly during navigation, such as Figure 1 , that is, the sinking amounts of the ship's center of gravity, bow, and stern are equal, and the overall sinking amount of the ship is calculated based on the equilibrium state condition. However, during actual navigation, a canal is a restricted waterway. Affected by the water flow boundary and hydrodynamic conditions, the sinking state of the ship is not completely parallel sinking, but shows significant non-uniform sinking characteristics. In particular, the sinking amount of the stern is often greater than that of the bow. Therefore, the existing formula fails to accurately reflect the true sinking state of the hull in the canal navigation environment, and there may be a large deviation between the calculation result and the actual situation.

[0007] Second, traditional calculation methods do not fully consider the coupled influence of the dynamic draft of the ship and hydrodynamic effects. During actual navigation, the draft depth of the ship is not fixed, but is dynamically affected by hydrodynamic forces, ship speed, and blockage effects, such as Figure 2 . Especially in restricted waterways such as canals, when the maximum sinking amount of the ship occurs, the instantaneous dynamic blockage ratio is usually greater than the static blockage ratio, which means that the cross-sectional area of the water flow occupied by the ship increases instantaneously, resulting in an increase in the return flow velocity. The increase in the return flow velocity further enhances the dynamic blockage ratio, forming an implicit coupling relationship between the sinking amount and the trim of the ship. This complex hydrodynamic interaction is not fully considered by the existing calculation methods, resulting in limited applicability of their calculation results in the canal environment.

[0008] In addition, existing methods ignore the influence of the trim of the ship in the canal on the sinking amount. Since a canal is an artificially channelized waterway, the cross-sectional shape is usually relatively regular. The ship is greatly affected by the restricted flow effect during navigation, resulting in significant changes in the water flow characteristics in the stern area, making the sinking amount of the stern greater than that of the bow. Traditional calculation methods do not fully consider this factor and still calculate according to the assumption of uniform sinking, which may lead to an underestimation of the actual maximum sinking amount, thereby affecting the reasonable determination of the water depth of the waterway.

[0009] To sum up, the existing ship sinking amount calculation methods have the following main problems in the canal waterway environment: single calculation basis, insufficient consideration of the particularity of the canal waterway, and low value of the navigation sinking amount, etc. These defects may cause the calculation result of the canal waterway depth to be lower than the actual demand in certain cases. Or it does not consider the actual non-uniform sinking characteristics; it fails to accurately reflect the implicit coupling relationship between the dynamic draft of the ship and hydrodynamic effects; it ignores the characteristics of the maximum sinking amount at the stern in the restricted canal waterway environment. These deficiencies may lead to a low calculated value of the canal waterway depth, affecting navigation safety. It is urgent to optimize the calculation method to more accurately reflect the true sinking characteristics of the ship in the canal. Therefore, there is an urgent need for a canal waterway depth calculation method based on the correction of the ship's navigation sinking amount to more accurately meet the navigation requirements of the canal waterway and improve navigation safety and engineering rationality. Summary of the Invention

[0010] In view of the problems existing in the current calculation method of the water depth of the canal waterway, such as the single calculation basis, the failure to fully consider the particularity of the canal as a restricted waterway, resulting in a low value of the navigation sinking amount and affecting the navigation safety, the present invention provides a calculation method for the water depth of the canal waterway optimized based on the navigation sinking amount of the ship.

[0011] The present invention is implemented as follows. A calculation method for the water depth of the canal waterway optimized based on the navigation sinking amount of the ship is characterized by including the following steps: determining the ship parameters and waterway parameters for calculating the ship sinking amount ; calculating the stern sinking amount through the ship sinking amount calculation formula by using the ship parameters and waterway parameters ; updating the ship parameters and waterway parameters according to the obtained stern sinking amount and iteratively calculating the stern sinking amount , n = 0, 1, 2..., when <10 -4 m, obtaining the corrected calculated water depth of the waterway H 3:

[0012]

[0013] Among them, T is the static draft depth of the ship, S is the safety clearance amount from the bottom stipulated by the navigation standard;

[0014] Obtaining the standard calculated water depth of the waterway through the inland waterway navigation standard H 2:

[0015] H 2 = T + △ H

[0016] Among them, T is the static draft depth of the ship, △ H is the additional water depth stipulated by the navigation standard;

[0017] Determining the minimum water depth of the waterway through the inland waterway navigation standard H 1;

[0018] Design value of the water depth of the waterway H Taking H 1, H 2, H the maximum value among 3.

[0019] In the above technical solution, preferably, the ship parameters and waterway parameters include the ship block coefficient , the ship displacement volume △, the waterline length L when the displacement volume is △, the stern widthB、 Draft at the stern of the ship when the displacement volume is △ Cross-sectional area of the waterway Cross-sectional area of the waterway at the stern of the ship 、 Ship speed v ; The formula for calculating the ship's sinkage is:

[0020]

[0021] where .

[0022] In the above technical solution, preferably, the iterative calculation formula is:

[0023] , n = 0, 1, 2...

[0024] where

[0025] ;

[0026] .

[0027] The present invention proposes a method for calculating the water depth of a canal waterway based on the correction of the ship's sinkage during navigation, which optimizes and improves the inapplicability of the existing method for determining the water depth of the waterway in the canal environment and the potential navigation safety hazards. This method has the following advantages and effects:

[0028] This method makes up for the deficiency of the existing calculation method that only considers the static sinkage of the ship. When calculating the additional water depth, the current standard mainly relies on the size and static sinkage of the ship, while ignoring the dynamic sinkage generated by the hydrodynamic action during the ship's navigation. In fact, in a restricted waterway such as a canal, the dynamic sinkage effect of the hull is particularly obvious, especially at a relatively high ship speed, and the sinkage at the stern is often much larger than the static calculated value. By introducing a dynamic sinkage correction factor, this method can more accurately evaluate the hull sinkage situation and make the calculation result more in line with the actual navigation conditions.

[0029] This method fully considers the non-uniformity of the ship during the sinking process. Traditional calculation methods usually assume that the ship sinks uniformly during navigation, but in actual situations, affected by factors such as the hull structure, ship speed, canalized water flow boundary, and other hydrodynamic factors, the sinkage at the bow and stern of the ship is often inconsistent, especially at high speeds, and the sinkage at the stern is more significant. By modifying the calculation model, this method can reasonably evaluate the influence of the non-uniform sinkage of the hull, so as to obtain a water depth value of the waterway that is more in line with the actual working conditions.

[0030] This method provides a water depth calculation method optimized based on the navigation characteristics of ships, which can provide a more scientific reference basis for channel maintenance, dredging planning and the formulation of navigation standards, and improve the accuracy and adaptability of canal channel management. By introducing a ship dynamic sinkage correction factor and comprehensively considering the particularity of the canal channel and the non-uniformity of ship sinkage, the calculated water depth value can better meet the actual needs. While improving navigation safety, it also provides a more accurate calculation method for the scientific management of canal channels. Description of the Drawings

[0031] Figure 1 is a schematic diagram of the sinkage of a ship in a static equilibrium assumed state;

[0032] Figure 2 is a schematic diagram of the sinkage of a ship in a dynamic equilibrium assumed state. Detailed Implementation Modes

[0033] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] To solve the problem in the current water depth calculation method for canal channels that the calculation basis is single, the particularity of the canal as a restricted channel is not fully considered, resulting in a low value of the navigation sinkage and affecting navigation safety, the present invention particularly provides a canal channel water depth calculation method optimized based on the ship navigation sinkage. To further illustrate the structure of the present invention, it is described in detail below in conjunction with the drawings:

[0035] According to relevant literature records, through the comparison of model test data with theoretical formulas such as the Barrass formula, Huuska-Guliev formula, Yoshimura formula, Eryuzlu formula, and Millward90 formula, it is found that the correlation between the measured and calculated sinkage values of the Barrass formula is the best in inland waterways. And because of its simple structure, the Barrass formula has become one of the most commonly used formulas for calculating ship sinkage. Therefore, the present invention aims to consider the element of uneven sinkage of the ship hull during the navigation process on the basis of the Barrass formula and correct the Barrass formula, so as to make the sinkage more accurate.

[0036] The present invention proposes a canal channel water depth calculation method optimized based on the ship navigation sinkage, including the following steps:

[0037] 1. Determine the ship parameters and channel parameters for calculating the ship sinkage of the ship.

[0038] The ship parameters and channel parameters include the ship block coefficient , the displacement volume of the ship △ (m 3 ), the waterline length when the displacement volume is △ L (m), the width of the ship's stern B (m) 、 The draft depth of the ship's stern when the displacement volume is △ (m), the cross-sectional area of the water passage in the waterway (m 2 ), the cross-sectional area of the water passage at the ship's stern (m 2 ) 、 Ship speed v (kn).

[0039]

[0040] Among them, b is the bottom width of the waterway, m is the side slope coefficient, h Take H 1, H the larger value of 2 ( H 2 = T + △ H , T is the static draft depth of the ship, △ H is the additional water depth specified by the navigation standard; H 1 is the minimum water depth of the waterway specified by the navigation standard).

[0041] 2. Calculate the stern sinkage using the ship parameters and waterway parameters through the ship sinkage calculation formula.

[0042] Based on the Barrass formula, considering the uneven hull sinkage factors during ship navigation, the formula is:

[0043] (1)

[0044] (2)

[0045] Among them, T is the static draft depth of the ship.

[0046] Comprehensively consider the scale of the planned freight volume of the waterway, the level of the waterway passing capacity, the navigation guarantee rate, and the fleet type, etc., to determine the waterway grade. The water depth of the waterway needs to be determined according to the waterway grade. Comprehensively consider the waterway transportation demands such as passenger and freight transportation, the existing ship types in the provinces and cities where the project section is located, the ship types specified by China's national standards, and the reference ship types similar to the project section at home and abroad, etc., to determine the design representative ship type of the project section. When necessary, the representative ship type of the project section can be determined by carrying out a special ship type research. After determining the representative ship type, the static draft depth T (unit: m) of the representative ship type design can be determined.

[0047] During the actual navigation of the ship, trim occurs, causing changes in the draft at the stern. Taking the vertical flow cross-section at the stern as the calculation cross-section, a correction formula is established according to the Barrass formula.

[0048] Cross-sectional area of the ship passing through water It is related to the overall sinking and trim of the ship. The sinking amount at the stern is the largest, denoted as:

[0049] (3)

[0050] In the formula, is the cross-sectional area of the ship's stern passing through water (m 2 ), B is the width of the stern (m), is the draft depth of the stern (m). Substitute formula (3) into formula (1), Adopt , then the sinking amount at the stern can be obtained.

[0051] (4)

[0052] 3. Update the ship parameters and channel parameters based on the obtained sinking amount at the stern and iteratively calculate the tail sinking amount , n = 0, 1, 2 …….

[0053] The sinking of the stern during navigation in the canal is a dynamic process. Use n = 0, 1, 2 …… to represent the steps in the dynamic change process. Considering the dynamic change process of the draft depth at the stern, correct formula (4) as follows:

[0054] Step 1:

[0055] (5)

[0056] In the formula: is the draft of the ship at the initial time, using the ship draft in formula (1) T .

[0057] Step 2:

[0058] (6)

[0059] Among them, .

[0060] Step 3:

[0061] (7)

[0062] Among them, .

[0063] Continue the iterative calculation to the n th step:

[0064] (8)

[0065] Among them, .

[0066] Revise the calculated channel depth H Determination of 3:

[0067] When <10 -4 m, take: , among which, T is the static draft of the ship, S is the safety clearance for touching the bottom stipulated by the navigation standard.

[0068] H 2 = T + △ H , among which, T is the static draft of the ship, △ H is the additional depth of water stipulated by the navigation standard, H 1 is the minimum channel depth stipulated by the navigation standard ； Design value of channel depth H Take H 1, H 2, H the maximum value among 3.

[0069] Minimum channel depth stipulated by the standard H Determination of 1:

[0070] According to Article 3.0.3, Table 3.0.3 of the Restricted Waterway Dimensions in the "Inland Waterway Navigation Standard" (GB50139 - 2014) and the relevant provisions of Article 4.2.4 of the "Canal Navigation Standard" (JTS180 - 2 - 2011), determine the minimum channel depth H 1.

[0071] Standard calculated channel depth H Determination of 2:

[0072] According to Appendix A, Article A.0.1 of the "Inland Waterway Navigation Standard" (GB50139 - 2014), the channel depth H 2 = T + △ H .

[0073] In the formula: The additional depth of water △H stipulated by the navigation standard is the additional depth of water (m), determined according to Appendix A, Table A.0.1;

[0074] Table 1 Allowance Depth Values (m) in Table A.0.1 of "Standards for Inland Waterway Navigation" (GB50139-2014)

[0075]

[0076] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A canal water depth calculation method optimized based on the sinking amount of ship navigation, characterized in that, Including the following steps: Determine the ship parameters and waterway parameters for calculating the ship's sinking amount ; Calculate the stern sinking amount through the ship sinking amount calculation formula using the ship parameters and waterway parameters ; Update the ship parameters and waterway parameters according to the obtained stern sinking amount and iteratively calculate the stern sinking amount , n = 0, 1, 2 ……, when <10 , H , , n , , -4 m, obtain the corrected calculated waterway depth H 3: Among them, T is the static draft of the ship, S is the safety clearance for touching the bottom stipulated by the navigation standard; The ship parameters and channel parameters include the block coefficient of the ship , the displacement volume △ of the ship, the waterline length when the displacement volume is △ L , the width of the ship's stern B、 the draft depth of the ship's stern when the displacement volume is △ , the cross-sectional area of the water flow in the channel , the cross-sectional area of the water flow at the ship's stern 、 the ship speed v ; The calculation formula for the ship's sinking amount is as follows: Among them, ; The iterative calculation formula is: ， n =0，1，2…… Wherein, ； ； The standard calculated channel depth obtained through the inland waterway navigation standard H 2: H 2= T +△ H Among them, T is the static draft of the ship, △ H is the additional depth of water specified by the navigation standard; Determine the minimum water depth of the waterway through the inland waterway navigation standard H 1; Design value of channel depth H Take H 1. H 2. H The larger value in 3.

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