Generalized dredging efficiency calculation method considering overflow effect of trailing suction dredger

Abstract

According to the generalized dredging efficiency calculation method considering the overflow effect of the trailing suction dredger, on the basis of the narrow dredging efficiency, the dredging effect calculation of overflow sediment diffusion out of a channel and the dredging effect calculation of transportation distance change caused by space change generated when the overflow sediment is secondarily silted back into the channel are increased; and the influence of overflow disturbance on the dredging efficiency is quantitatively calculated, a generalized dredging efficiency calculation model and a generalized dredging amount process curve are formed, and generalized optimal overflow time and generalized optimal dredging amount are searched. According to the method, the influence of overflow disturbance of the trailing suction dredger on the dredging efficiency is considered, quantitative calculation is achieved, the method can be used for guiding dredging construction, improvement of the dredging efficiency and reduction of energy consumption are facilitated, and refined and low-carbon development of dredging operation is further promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of waterway dredging and relates to a generalized dredging efficiency calculation method taking into account the overflow effect of a trailing suction hopper vessel. Background Art

[0002] Trailing suction hopper dredgers are widely used in waterway dredging projects in my country and around the world. Dredged volume is measured using two main methods: bathymetric measurement (underwater) and shipborne measurement (abovewater). However, for large waterways with significant backfilling intensity, which require continuous dredging, bathymetric measurement is not applicable, requiring shipborne measurement. Therefore, in the current dredging construction specification ("Construction Specification for Dredging and Filling Projects") (JTS207-2012) and in real-world practice, shipborne loading curves are required to analyze and calculate construction efficiency and identify the optimal overflow time.

[0003] During the dredging process, a trailing suction hopper vessel typically overflows for a period of time to increase the density and volume of dredged soil within the vessel's hold. Consequently, not all of the dredged soil sucked into the hold ultimately remains there, and a significant portion flows out of the hold through the overflow port. This portion, from an underwater perspective, is also considered part of the dredged volume. Some of this overflowing dredged soil is carried out of the waterway by the tide, directly impacting dredging efficiency. Another portion re-deposits and settles back into the waterway, creating new changes in its spatial distribution. This affects the distance and round-trip time required for secondary dredging, indirectly impacting dredging efficiency.

[0004] As shipborne cubic meters accumulate and overflow time accumulates, the effects of overflow disturbance cannot be ignored, especially in waterways with strong tidal forces. Since shipborne cubic meters are currently the primary method of measurement and pricing in China, mainstream research has focused on improving shipborne cubic meter loading efficiency and reducing overflow losses, with less research on overflow effects. A few scholars have used sediment movement theory formulas and other methods to roughly estimate the proportion of overflow sediment that drifts laterally out of the channel. However, no research has been conducted on the proportion that drifts longitudinally out of the channel, the spatial distribution of sediment that re-enters the channel longitudinally, and its impact on dredging efficiency. Currently, there is no comprehensive method for calculating the overall overflow effect and its impact on dredging efficiency. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a generalized dredging efficiency calculation method taking into account the overflow effect of a trailing suction hopper vessel.

[0006] Based on the narrow dredging efficiency (ship-borne cubic meters) in the "Construction Specification for Dredging and Filling Engineering" (JTS207-2012), the present invention proposes a generalized dredging efficiency calculation method based on overflow disturbance, which adds 1) the calculation of the dredging effect of the diffusion (including lateral and longitudinal) of overflow sediment out of the channel and 2) the calculation of the dredging effect of the spatial variation caused by the secondary sedimentation of overflow sediment back into the channel causing the change in transport distance. The method can quantitatively calculate the impact of overflow disturbance on dredging efficiency, and combine it with the narrow dredging efficiency to form a generalized dredging efficiency calculation model and a generalized dredging volume process curve, and find the generalized optimal overflow time and generalized optimal dredged volume.

[0007] A generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel comprises the following steps:

[0008] Step 1: Through on-site observation of the dredging operation of the trailing suction hopper vessel, hourly data such as the vessel's loading process curve, overflow sediment content, and flow rate are obtained;

[0009] Step 2: Establish a narrow dredging efficiency calculation model W 狭义 , find the narrow optimal overflow time t 狭义 ;

[0010] Step 3: numerical model calculation to obtain the loss rate δ of overflow sediment spreading out of the channel and the ratio and spatial distribution of secondary sedimentation back into the channel;

[0011] Step 4: Establish a generalized dredging efficiency calculation model W 广义 ;

[0012] Step 5: Find the generalized optimal overflow time t 广义 and the generalized optimal dredging volume H 广义(优) .

[0013] Furthermore, the vessel-borne cubic meter loading process curve of the trailing suction hopper vessel in step 1 needs to be smoothly fitted based on the original data.

[0014] Furthermore, the numerical model calculation in step three is a numerical model of the bottom overflow of the trailing hopper vessel obtained by improving and optimizing the actual situation of the bottom overflow of the trailing hopper vessel.

[0015] Furthermore, the loss rate δ of the overflow sediment diffused out of the channel range and the proportion and spatial distribution of secondary sedimentation back to the channel in step 3 are calculated by respectively calculating the channel beach surface change and overflow volume q under two working conditions with and without overflow behavior. 溢流 The weighted downward displacement distance Δl of the secondary back-silting soil is calculated as shown in Formula 3:

[0016]

[0017] In formula 3,

[0018] △q 二次回淤i is the volume change of the beach surface of each unit channel under the two working conditions of overflow behavior and no overflow behavior;

[0019] △l i The volume change of each unit channel beach corresponds to the transport distance of the overflow unit, with a decrease in transport distance being represented by + and an increase by -.

[0020] Furthermore, the generalized dredging efficiency calculation model W is established as described in step 4. 广义 Calculation methods include:

[0021] a. Establish a calculation model for the overflow loss efficiency of overflow sediment diffusion out of the channel W 溢流流失 ;

[0022] b. Establish a calculation model for the dredging efficiency of overflow secondary siltation, which considers the change in the position of sediment in the channel and the change in the transport distance caused by the secondary siltation of overflow sediment. 溢流二次回淤 ;

[0023] c. Establish a generalized dredging efficiency calculation model W 广义 .

[0024] Furthermore, the overflow loss efficiency W of the overflow sediment diffusing out of the channel is 溢流流失 The calculation formula is:

[0025]

[0026] In formula 4,

[0027] W 溢流流失 ——Overflow loss efficiency;

[0028] q 溢流 — overflow volume;

[0029] δ—loss rate of overflow sediment spreading out of the channel;

[0030] ∑t——Construction cycle operation time (min).

[0031] Furthermore, the overflow sediment secondary siltation causes the sediment position change in the channel and the overflow secondary siltation dredging efficiency W changes due to the change in transport distance. 溢流二次回淤 The calculation formula is:

[0032]

[0033] In Formula 5 and Formula 6,

[0034] W 溢流二次回淤 The efficiency of secondary dredging for overflow;

[0035] q 溢流 is the overflow volume;

[0036] δ is the loss rate of overflow sediment spreading out of the channel;

[0037] △l1 is the transport distance of the overflow unit corresponding to the change volume of the heavy-load unit channel beach;

[0038] △l2 is the transport distance of the overflow unit corresponding to the change volume of the empty unit channel beach;

[0039] v1 is the heavy-load speed (km / h);

[0040] v2 is the no-load speed (km / h).

[0041] Furthermore, the generalized dredging efficiency W 广义 The calculation formula is:

[0042] W 广义 =W 狭义 +W 溢流流失 +W 溢流二次回淤 (Formula 7)

[0043] In formula 7,

[0044] W 广义 For the generalized dredging efficiency;

[0045] W 狭义 For dredging efficiency in a narrow sense;

[0046] W 溢流流失 Dredging efficiency for overflow losses;

[0047] W 溢流二次回淤 The overflow secondary siltation dredging efficiency.

[0048] Furthermore, the generalized optimal overflow time and the generalized optimal dredging volume in step five are determined by the generalized construction efficiency and the generalized dredging volume process curve.

[0049] Compared with the existing technology, the beneficial effects of the present invention are:

[0050] 1. The present invention is a generalized dredging efficiency calculation method that takes overflow effects into account. On the basis of narrow dredging efficiency (ship-borne cubic meters), the dredging efficiency calculation of overflow loss caused by overflow disturbance out of the channel and the dredging efficiency calculation of overflow secondary siltation caused by spatial changes in the channel are added. This method can quantitatively calculate the impact of overflow disturbance on dredging efficiency.

[0051] 2. The present invention is combined with the narrow dredging efficiency to form a generalized dredging efficiency calculation model and a generalized dredging volume process curve, and to find the generalized optimal overflow time and the generalized optimal dredging volume, which can be used to guide dredging construction. The dredging vessel can dynamically adjust the overflow time according to the hydrological characteristics of the section and construction period, which is conducive to improving dredging efficiency, reducing energy consumption, and further promoting the refinement and low-carbon development of dredging operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a flow chart of a generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel in the present application.

[0053] Figure 2 This is a graph of the original data and fitting curve of the ship-borne party in the embodiment of the present application.

[0054] Figure 3 It is a schematic diagram of the distribution curve of the loading volume and the loading overflow time of the embodiment of the present application.

[0055] Figure 4 It is a schematic diagram of the narrow construction efficiency distribution curve of the embodiment of the present application.

[0056] Figure 5 It is a schematic diagram of the improvement of the numerical model of the bottom overflow of the trailing suction hopper vessel in the embodiment of the present application.

[0057] Figure 6 It is a schematic diagram of the generalized dredging efficiency distribution curve of the embodiment of the present application.

[0058] Figure 7 It is a schematic diagram of the distribution curve of generalized dredging volume and loading overflow time in an embodiment of the present application.

[0059] Figure 8 This is the original data of the shipborne square and overflow flow in the embodiment of this application.

[0060] Figure 9 This is a narrow construction efficiency distribution curve diagram of the embodiment of the present application.

[0061] Figure 10 This is a distribution curve diagram of the loading volume and the loading overflow time of the embodiment of the present application.

[0062] Figure 11 It is a generalized dredging efficiency distribution curve diagram of an embodiment of the present application.

[0063] Figure 12 This is a distribution curve of generalized dredging volume and loading overflow time in an embodiment of the present application. DETAILED DESCRIPTION

[0064] The present invention is further described below with reference to embodiments and accompanying drawings.

[0065] A generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel comprises the following steps:

[0066] Step 1: Obtain the vessel loading process curve, overflow sediment content, flow rate and other data through on-site observation of the dredging operation of the dredger: The vessel loading process curve is usually obtained by using the ship-borne automatic earthwork measuring instrument and then smoothed and fitted, such as Figure 2 As shown, the ship-borne cubic meters can also be calculated manually by ship by ship through construction data. It should be noted that the ship-borne cubic meters need to be converted into the original earthwork in the dredging area; the overflow sediment content can be obtained by converting the concentration data obtained by hourly sampling in the overflow tube of the trailing suction hopper ship. The conversion formula is shown in Formula 1; the overflow flow rate is obtained by the ship-borne automatic earthwork measuring instrument.

[0067] S 溢流 =C 溢流 (ρ 疏浚土 -ρ 海水 )-ρ 海水 (Formula 1)

[0068] In formula 1,

[0069] S 溢流 is the overflow sediment content (kg / m 3 );

[0070] C 溢流 is the overflow concentration (%), which can be obtained from the overflow tube of the trailing suction hopper using a density meter;

[0071] ρ 疏浚土 is the density of dredged soil (kg / m 3 ), which is related to the properties of the dredged soil in the area;

[0072] ρ 海水 is the density of seawater, usually taken as 1.0025×10 3 kg / m 3 .

[0073] Step 2: Establish a narrow dredging efficiency calculation model W 狭义 , find the narrow optimal overflow time t 狭义 According to the relevant provisions of the "Dredging and Filling Engineering Construction Specifications" (JTS207-2012), combined with the cycle time of each step of dredging construction, the distribution curve of the relationship between loading volume and loading overflow time is established as follows: Figure 3 As shown, the narrow dredging efficiency calculation model W that only considers the ship-borne party is calculated according to formula 2 狭义 , the operation time corresponding to the maximum value is the narrow optimal overflow time t 狭义 ,like Figure 4 shown.

[0074]

[0075] In formula 2, q1 is the earthwork volume loaded in the mud tank (m 3 ), which is W 狭义 , can be obtained through the ship-borne cubic loading process curve;

[0076] ∑t is the construction cycle operation time (min);

[0077] l1 is the length of the heavy-load navigation section (km);

[0078] v1 is the heavy-load speed (km / h);

[0079] l2 is the length of the empty flight segment (km);

[0080] v2 is the no-load speed (km / h);

[0081] l3 is the dredging length (km);

[0082] v3 is the dredging speed (km / h);

[0083] t1 is the time of mud throwing and turning during mud throwing (min);

[0084] t2 is the time for turning and going online during construction (min).

[0085] Step three, numerical model calculation to obtain the loss rate δ of overflow sediment diffusion out of the channel range and the proportion of secondary siltation to the channel and its spatial distribution: The mathematical model of bottom overflow of the hopper vessel is in the "Three-dimensional Estuary Coastal Hydrodynamics and Sediment Numerical Simulation Software" (SHIWM-3D, which has been registered as a software copyright by the National Copyright Administration). According to the engineering characteristics of the bottom overflow of the hopper vessel, by improving the three-dimensional flow field-sediment coupling algorithm and optimizing the boundary condition parameters, a numerical model that can simulate the bottom overflow sediment diffusion process is constructed. The model calculates the amount of channel sedimentation caused by bottom overflow sediment in a certain period of time, thereby quantifying the loss rate δ of overflow sediment diffusion outside the channel. At the same time, based on the sediment sedimentation-resuspension mechanism, it analyzes the proportion of sediment that is secondary silted into the channel and its spatial distribution characteristics, such as Figure 5 As shown in the figure, the loss rate δ of overflow sediment spreading out of the channel and the proportion and spatial distribution of secondary sedimentation back into the channel are calculated by calculating the channel topography change and overflow sediment volume q under two working conditions: with overflow and without overflow. 溢流 The calculation results are shown in Table 1, where the weighted downward movement distance Δl of the secondary siltation soil is obtained by weighted average of the spatial distribution from the secondary siltation soil to the waterway, as shown in Formula 3.

[0086] Table 1 Calculation results of overflow disturbance numerical simulation at a certain channel location

[0087]

[0088]

[0089] Note: If Δl is a negative value, it means the transport distance is reduced; if it is a positive value, it means the transport distance is increased.

[0090]

[0091] In formula 3,

[0092] Δq 二次回淤i is the volume change of the beach surface of each unit channel under the two working conditions of overflow behavior and no overflow behavior;

[0093] Δ li The volume change of each unit channel beach corresponds to the transport distance of the overflow unit, with a decrease in transport distance being represented by + and an increase by -.

[0094] Step 4: Establish a generalized dredging efficiency calculation model W 广义 : Calculate the overflow loss dredging efficiency W of the overflow disturbance diffusion out of the channel 溢流流失 The overflow secondary siltation dredging efficiency W caused by the spatial change of the secondary siltation to the channel 溢流二次回淤 , and W 狭义 The sum of the three gives the generalized dredging efficiency calculation model W 广义 , W 溢流流失 The calculation formula is shown in Formula 4, W 溢流二次回淤 The calculation formula is shown in formula 5 and 6, W 广义 The calculation formula is shown in Formula 7.

[0095]

[0096] W 广义 =W 狭义 +W 溢流流失 +W 溢流 Secondary siltation (Formula 7)

[0097] In formula 6,

[0098] Δ l1 The transport distance of the overflow unit corresponding to the change volume of the heavy-load unit channel beach;

[0099] Δ l2 The volume change of the empty unit channel beach corresponds to the transport distance of the overflow unit.

[0100] Step 5: Find the generalized optimal overflow time t 广义 and the generalized optimal dredging volume H 广义(优) :W 广义 The operating time corresponding to the maximum is the generalized optimal overflow time t 广义 ,like Figure 7 As shown; the generalized dredging volume H is calculated by formula 8广义 , the distribution curve of generalized dredging volume during the construction cycle is obtained as follows Figure 6 As shown, the generalized optimal overflow time t 广义 The corresponding dredging volume is the generalized optimal dredging volume H 广义(优) ;

[0101] H 广义 =(W 狭义 +W 溢流流失 +W 溢流二次回淤 )×∑t (Formula 8)

[0102] Taking a section of a Yangtze River channel as an example, a 12,000-cubic-meter trailing suction hopper vessel was used for maintenance dredging. The average distance of dredged soil excavated, transported, and dumped to the dumping area for disposal was 66 km. The round trip, including mud dumping and turning around, took about 348 minutes. The specific steps are as follows:

[0103] Step 1: Through on-site observation of the dredging operation of the trailing suction hopper vessel, the ship-borne cubic meter loading process curve, overflow sediment content and flow rate data are obtained: the ship-borne cubic meter (converted into the original earthwork in the dredged area) and the overflow flow rate are obtained using the ship-borne automatic earthwork metering instrument. Figure 8 As shown in the figure; the loading process curve of the trailing suction hopper ship is smoothly fitted as shown in the figure Figure 2 As shown in the figure, the overflow sediment content is obtained by converting the overflow concentration obtained by sampling at the overflow port hourly. The average overflow process is 80kg / m 3 .

[0104] Step 2: Establish a narrow dredging efficiency calculation model W 狭义 , find the narrow optimal overflow time t 狭义 :According to W 狭义 The calculation formula shows that the narrow optimal overflow time is 142 minutes, and the narrow optimal loading efficiency is 14.67m 3 / min(880m 3 / h), as follows Figure 9 As shown; the corresponding ship's carrying capacity at the time is 7190m 3 , specifically Figure 10 shown.

[0105] Step 3: The numerical model is used to calculate the loss rate of overflow sediment out of the channel and the ratio and spatial distribution of secondary sedimentation to the channel: The loss rate δ of overflow sediment out of the channel and the spatial distribution of secondary sedimentation to the channel are calculated by calculating the channel beach surface changes and overflow volume q under two working conditions: overflow behavior and no overflow behavior. 溢流 The weighted downward displacement distance Δl of the secondary siltation soil is obtained by weighted average of the spatial distribution from the secondary siltation to the channel. The calculation results are shown in Table 1.

[0106] Step 4: Establish a generalized dredging efficiency calculation model W广义 : Calculate the overflow loss dredging efficiency W of the overflow disturbance diffusion out of the channel 溢流流失 The overflow secondary siltation dredging efficiency W caused by the spatial change of the secondary siltation to the channel 溢流二次回淤 , and W 狭义 The sum of the three gives the generalized dredging efficiency calculation model W 广义 Calculate W according to formula 4 to formula 7 respectively. 溢流流失 、W 溢流二次回淤 and W 广义 , the calculation results are as follows Figure 11 shown.

[0107] Step 5: Find the generalized optimal overflow time t 广义 and the generalized optimal dredging volume H 广义(优) :like Figure 11 As shown, when t = 147min, W 广义 Maximum, generalized optimal overflow time t 广义 The optimal dredging efficiency is 17.44m 3 / min(1046m 3 / h); The curve distribution of generalized dredging volume during the ship shift operation can be obtained by calculation using formula 8 as follows Figure 12 As shown in the figure, at t = 147 min, the generalized optimal dredging volume H 广义(优) 8364m 3 .

[0108] The comparison of narrow dredging and broad dredging indicators is shown in Table 2. The narrow optimal overflow time is about 142 minutes, and the dredging efficiency is 14.67m 3 / min(880m 3 / h), the optimal loading volume is 7190m 3 After considering the generalized construction efficiency, the generalized optimal overflow time increases to 147 minutes, and the dredging efficiency is 17.44m 3 / min(1046m 3 / h), the optimal dredging volume increased to 8364m 3 The general construction efficiency under the best loading conditions is about 19% higher than the narrow construction efficiency.

[0109] Table 2 Comparison of narrow dredging and broad dredging indicators

[0110]

[0111] The above description of the embodiments is intended to facilitate understanding and use of the present invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention are within the scope of protection of the present invention.

Claims

1. A generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel, characterized in that: On the basis of narrow dredging efficiency, the calculation of dredging effect of overflow sediment diffusion out of the channel and the calculation of dredging effect of spatial change caused by secondary sedimentation of overflow sediment into the channel causing change in transport distance are added. The influence of overflow disturbance on dredging efficiency is quantitatively calculated to form a generalized dredging efficiency calculation model and a generalized dredging volume process curve, and the generalized optimal overflow time and generalized optimal dredging volume are found.

2. The generalized dredging efficiency calculation method considering the overflow effect of the trailing suction hopper vessel according to claim 1 is characterized in that: The following steps are involved: Step 1: Through on-site observation of the dredging operation of the trailing suction hopper vessel, hourly data such as the vessel's loading process curve, overflow sediment content, and flow rate are obtained; Step 2: Establish a narrow dredging efficiency calculation model W 狭义 , find the narrow optimal overflow time t 狭义 ; Step 3: numerical model calculation to obtain the loss rate δ of overflow sediment spreading out of the channel and the ratio and spatial distribution of secondary sedimentation back into the channel; Step 4: Establish a generalized dredging efficiency calculation model W 广义 ; Step 5: Find the generalized optimal overflow time t and the generalized optimal dredging volume H 广义(优) .

3. The generalized dredging efficiency calculation method considering the overflow effect of the trailing suction hopper vessel according to claim 2 is characterized by: The loading process curve of the trailing suction hopper vessel in step 1 needs to be smoothly fitted based on the original data.

4. The generalized dredging efficiency calculation method considering the overflow effect of the trailing suction hopper vessel according to claim 2 is characterized in that: The numerical model calculation in step three is a numerical model of the bottom overflow of a trailing hopper vessel obtained by improving and optimizing the actual situation of the bottom overflow of the trailing hopper vessel.

5. The generalized dredging efficiency calculation method considering the overflow effect of the trailing suction hopper vessel according to claim 2 is characterized in that: The loss rate δ of overflow sediment spreading out of the channel and the proportion and spatial distribution of secondary sedimentation back to the channel mentioned in step 3 are calculated by calculating the channel beach surface change and overflow volume q under two working conditions with and without overflow behavior. 溢流 The weighted downward displacement distance Δl of the secondary backfill soil is calculated as shown in Formula 3: In formula 3, △q 二次回淤i is the volume change of the beach surface of each unit channel under the two working conditions of overflow behavior and no overflow behavior; △l i The volume change of each unit channel beach corresponds to the transport distance of the overflow unit, with a decrease in transport distance being represented by + and an increase by -.

6. The generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel according to claim 2 is characterized in that: The generalized dredging efficiency calculation model W is established as described in step 4. 广义 Calculation methods include: a. Establish a calculation model for the overflow loss efficiency of overflow sediment diffusion out of the channel W 溢流流失 ; b. Establish a calculation model for the dredging efficiency of overflow secondary siltation, which considers the change in the position of sediment in the channel and the change in the transport distance caused by the secondary siltation of overflow sediment. 溢流二次回淤 ; c. Establish a generalized dredging efficiency calculation model W 广义 .

7. The generalized dredging efficiency calculation method considering the overflow effect of the trailing suction hopper vessel according to claim 6 is characterized by: The overflow loss efficiency W of the overflow sediment spreading out of the channel 溢流流失 The calculation formula is: In formula 4, W 溢流流失 ——Overflow loss efficiency; q 溢流 — overflow volume; δ—loss rate of overflow sediment spreading out of the channel; ∑t——Construction cycle operation time (min).

8. The generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel according to claim 6 is characterized in that: The overflow sediment secondary siltation causes the sediment position change in the channel and the transport distance change, resulting in the overflow secondary siltation dredging efficiency W 溢流二次回淤 The calculation formula is: In Formula 5 and Formula 6, W 溢流二次回淤 The efficiency of secondary dredging for overflow; q 溢流 is the overflow volume; δ is the loss rate of overflow sediment spreading out of the channel; △l1 is the transport distance of the overflow unit corresponding to the change volume of the heavy-load unit channel beach; △l2 is the transport distance of the overflow unit corresponding to the change volume of the empty unit channel beach; v1 is the heavy-load speed (km / h); v2 is the no-load speed (km / h).

9. The generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel according to claim 6 is characterized in that: The generalized dredging efficiency W 广义 The calculation formula is: W 广义 =W 狭义 +W 溢流流失 +W 溢流二次回淤 (Formula 7) In formula 7, W 广义 For the generalized dredging efficiency; W 狭义 For dredging efficiency in a narrow sense; W 溢流流失 Dredging efficiency for overflow losses; W 溢流二次回淤 The overflow secondary siltation dredging efficiency.

10. The generalized dredging efficiency calculation method considering the overflow effect of a trailing suction hopper vessel according to claim 2 is characterized in that: The generalized optimal overflow time and the generalized optimal dredging volume described in step five are determined by the generalized construction efficiency and the generalized dredging volume process curve.

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