A method for controlling the dredging of hard soil in a cutter suction mode

Abstract

A control method for dredging hard soil in a cutter suction dredging operation mode is disclosed. The dredging operation includes two core stages: excavating the hard soil and transporting the hard soil. During the excavation process, the particle size of the excavated hard soil is controlled by adjusting cutting parameters. The particle size of the hard soil further limits the transport parameters during transport. This control method is applicable to equipment using cutterheads and mud pumps for dredging operations. This invention analyzes the interaction between cutting and transport parameters, monitors and regulates key parameters during the dredging process, and provides parameter control methods under different abnormal operating conditions to ensure the safe, efficient, and stable operation of the entire dredging operation. It solves the problem that changes in soil particle size during hard soil dredging complicate the analysis and control of operating parameters.

Description

Technical Field

[0001] This invention belongs to the field of dredging engineering technology, specifically relating to a control method for dredging hard soil under a cutter suction operation mode. Background Technology

[0002] Cutter suction dredging is a typical operation mode in dredging projects, usually employing cutterheads and mud pumps. During dredging using cutter suction dredging, the key focus is on controlling the excavation output and conveying volume; therefore, monitoring and controlling key parameters is crucial.

[0003] In the excavation of soils such as sand and gravel, the particle size of the soil is fixed, that is, the size of the sand and gravel themselves. However, in the excavation of hard soil, due to the special characteristics of hard soil, the particle size of the soil entering the conveying pipeline is not the size of the particles that make up the soil, but depends on the cutting parameters. This makes the parameters of the dredging operation complex and variable, bringing new challenges to the control of the entire dredging process.

[0004] Therefore, it is necessary to integrate the excavation and transportation stages to regulate the relevant parameters in the dredging process of hard soil, and thus provide a control method for hard soil dredging under the suction chuck operation mode. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a control method for dredging hard soil in a cutter suction dredging operation mode. This method is applicable to various equipment used for dredging operations with cutterheads and mud pumps, including but not limited to various types of cutter suction dredgers and cutter suction sludge removal robots.

[0006] The technical solution adopted in this invention is as follows:

[0007] A control method for dredging hard soil in a cutter suction operation mode, wherein the dredging operation in the cutter suction operation mode includes two core links: excavating hard soil and conveying hard soil. In the process of excavating hard soil, the particle size of the hard soil cut off is controlled by adjusting the cutting parameters. The particle size of the hard soil further limits the conveying parameters in the process of conveying hard soil. The control method is applicable to equipment that uses cutterheads and mud pumps for dredging operations.

[0008] The cutting parameters include cutter speed, cutter lateral speed, and cutter burial depth. These cutting parameters, combined with hard soil parameters, are used to calculate excavation output, soil particle size, and cutting force through a mathematical model. The conveying parameters include slurry velocity, conveying concentration, and conveying flow rate. The excavation output is combined with mud pump and pipeline parameters, namely mud pump-flow characteristic curve, mud pump speed, and pipeline length and diameter, and the slurry velocity, conveying concentration, and conveying flow rate are calculated based on empirical formulas.

[0009] The resultant velocity of the cutterhead's lateral movement velocity and the cutterhead tooth tip linear velocity is the soil particle velocity, and the cutterhead tooth tip linear velocity = 2πR*n 绞刀转速 R is the radius of the cutter head; the parameter of the hard soil is the soil cohesion.

[0010] Furthermore, the formula for calculating the soil particle size 'a' is as follows:

[0011]

[0012] In equation (1), V S denoted as tangent traverse speed, n as tangent rotation speed, and m as the number of rows of teeth on the tangent.

[0013] Furthermore, the same mud pump has different head-flow characteristic curves when operating at different speeds, according to the proportionality law. The pump speed increases, and the flow rate increases.

[0014] Furthermore, the equipment to which the control method is applicable includes large-scale cutter systems and small-scale cutter systems; for large-scale cutter systems, the delivery concentration is controlled at 15-25%; for small-scale cutter systems, the delivery concentration is controlled at 11-17%.

[0015] Furthermore, the large cutterhead system includes a dredging cutter suction vessel, and the small cutterhead system includes an environmentally friendly cutter suction vessel and a cutter suction dredging robot.

[0016] Furthermore, the upper limit of the soil particle velocity is 30% of the suction inlet velocity, as expressed by the following formula:

[0017] V 土粒速度 ≤30%V 吸口流速 (2)

[0018] V 吸口流速 =Q 输送流量 / S 吸口面积 (3)

[0019] In equation (3), S 吸口面积 S represents the suction area of ​​the pipe inlet inside the cutter head. For the selected dredging equipment, S 吸口面积 It is a constant.

[0020] Furthermore, based on the combination of the conveying concentration and soil particle size, the critical flow velocity is calculated using an empirical formula, and the slurry flow velocity is 1.1-1.5 times the critical flow velocity; at the same time, the cutter is driven by an electric motor or a hydraulic motor, and the cutting force of the cutter is limited by the structural strength, and the maximum allowable value of the cutter power is the rated power of the electric motor or hydraulic motor.

[0021] Furthermore, based on the selected dredging equipment and after the excavation and transportation matching calculations have been completed, key data during the dredging process are monitored and controlled. The monitoring parameters include the slurry flow rate, transportation concentration, soil particle velocity, and cutter power in the pipeline, while the control parameters include the cutter rotation speed, cutter lateral movement speed, cutter burial depth, and mud pump speed.

[0022] Furthermore, different control methods are adopted in the following five situations:

[0023] (1) When the slurry flow rate is <1.1*critical flow rate and the delivery concentration is too high, first increase the speed of the mud pump to quickly increase the slurry flow rate, then reduce the cutter cross-movement speed to reduce the soil particle size, reduce the critical flow rate, and also reduce the excavation output, thereby reducing the delivery concentration.

[0024] (2) When the slurry flow rate is less than 1.1*critical flow rate and the conveying concentration is low, the cutter speed should be increased first and the soil particle size should be reduced. At the same time, the cutter power should be kept away from exceeding the upper limit of power, and the soil particle velocity should be calculated and kept away from exceeding the upper limit of soil particle velocity to avoid a large amount of omission.

[0025] (3) When the slurry velocity is >1.5*critical velocity and the conveying concentration is too high, first reduce the speed of the mud pump to reduce energy waste; second, reduce the speed of the cutter and reduce the power of the cutter to further reduce energy consumption while meeting the dredging requirements; finally, reduce the lateral speed of the cutter to reduce the conveying concentration and avoid local sudden increase in concentration that could cause pipe blockage.

[0026] (4) When the slurry velocity is >1.5*critical velocity and the delivery concentration is low, first increase the cutter lateral speed to increase excavation output, but at the same time, it is necessary to avoid the cutter power from exceeding the upper limit of power, and calculate the soil particle velocity, and avoid it from exceeding the upper limit of soil particle velocity to avoid a large amount of omission; secondly, increase the cutter burial depth to increase excavation output; if the slurry velocity is still too high after the delivery concentration is increased, then adjust according to the third situation.

[0027] (5) When the power of the cutter suddenly increases due to the sudden hardening of the soil, the cutter lateral movement speed should be reduced first, and the cutter rotation speed should be increased within the allowable range of the cutter power. The soil particle velocity should be calculated and it should be avoided to exceed the upper limit of the soil particle velocity in order to avoid a large amount of omission.

[0028] The beneficial effects of the control method of the present invention are as follows:

[0029] The control method for dredging hard soil under the cutter suction operation mode of the present invention monitors and regulates key parameters in the dredging process by analyzing the mutual influence between cutting parameters and conveying parameters, and provides parameter regulation methods under different abnormal operating conditions to ensure the safe, efficient and stable operation of the entire dredging operation. It solves the problem that the analysis and control of operating parameters become more complicated due to changes in soil particle size during the dredging of hard soil. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the control method for dredging operations in hard soil.

[0031] Figure 2 This is a schematic diagram of the cross-section of the reamer during the cutting process.

[0032] Figure 3 This is a diagram showing the matching of the mud pump pipeline transportation system.

[0033] Figure 4 This is the working concentration curve of the mud pump pipeline transportation system.

[0034] Figure 5 This is the working flow rate curve of the mud pump pipeline transportation system. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0036] This invention discloses a control method for dredging hard soil in a cutter suction operation mode. The dredging operation in the cutter suction operation mode includes two core links: excavating hard soil and transporting hard soil. Due to the special characteristics of hard soil, the particle size of the cut hard soil is controlled by adjusting the cutting parameters during the excavation process. The particle size of the hard soil further affects the transport parameters during the transport process.

[0037] The control method is applicable to various equipment that uses cutterheads and mud pumps for dredging operations, including large cutterhead systems such as large dredging cutter suction vessels, as well as small cutterhead systems such as environmentally friendly cutter suction vessels and cutter suction dredging robots.

[0038] The principle of the control method for hard soil dredging is as follows: Figure 1 As shown, the cutting parameters include cutter speed, cutter lateral speed, and cutter burial depth. These cutting parameters, combined with hard soil parameters, are used to calculate excavation output, soil particle size, and cutting force through a mathematical model.

[0039] The conveying parameters include slurry velocity, conveying concentration, and conveying flow rate. The excavation output is combined with the mud pump and pipeline parameters, namely the mud pump head-flow characteristic curve, mud pump speed, and pipeline length and diameter, and the slurry velocity, conveying concentration, and conveying flow rate are calculated based on empirical formulas.

[0040] This paper takes a cutter suction underwater dredging robot as an example to analyze the relationship between cutting parameters and conveying parameters during the dredging of hard soil in cutter suction operation mode. Based on the above relationship, parameter adjustment methods under different abnormal operating conditions are given to ensure the safe, efficient and stable operation of the entire dredging operation. The cutter diameter of the robot is 300mm, and the diameter of the conveying pipe is 100mm.

[0041] Example 1, Cutting Parameters

[0042] (1) Relationship between cutter rotation speed and cutter lateral velocity and soil particle size

[0043] A schematic diagram of the cross-section of the reamer cutting process is shown below. Figure 2 As shown, the cutting trajectory of all the teeth on the reamer rotating one revolution is represented by each trajectory line being equivalent to the previous trajectory line being translated in the cutting direction by the same length, i.e., the cutting thickness. Let the cutting thickness be a, which can be expressed by the formula:

[0044]

[0045] In formula (1), m is the number of rows of teeth on the reamer. Figure 2 In this context, m is 6; n is the cutter speed in r / min; a is in meters; V s The lateral movement speed of the cutter is m / s.

[0046] This invention discovered in experiments that the soil particles formed after cutting hard soil are closely related to the shape of the cutting teeth. In this invention, the particles are mostly sheet-like, with the same width as the cutting teeth, and the thickness is basically the same as the cutting thickness. The initially cut broken soil is basically strip-shaped. After passing through the grid, pipeline transportation, and mud pump, the soil strips break. Observation from the pipeline outlet shows that the soil particles still retain a certain size, forming irregular blocks, with the blocks still basically retaining a thickness of 'a'. The actual particle size of the transported soil can be considered to be 'a'. The smaller the soil particle size 'a', that is, the smaller the thickness of the soil layer cut by a single cutting tooth, the smaller the cutting force, and the smaller the soil particles formed after cutting hard soil, which is more conducive to suction and transportation.

[0047] (2) Relationship between reamer embedment depth and cutting force

[0048] The cutting force calculation method in the reference "Load Analysis of Cutter Head of Cutter Suction Dredger Based on Two-Dimensional Cutting Theory" calculates the three-dimensional force of the cutter head during the dredging process based on the cutter head burial depth, cutter head parameters, and relevant parameters of hard soil. On this basis, the cutting torque, cutting power and dredging output of the cutter head at different times are obtained, and the calculation results change dynamically with time.

[0049] The accuracy of the calculation method was verified by an experiment of cutting hard soil with a cutter. The experimental results are shown in Table 1 below.

[0050] Table 1: Test results of awl cutting hard soil

[0051]

[0052] Furthermore, the above method was used to calculate the stress, cutting torque, cutting power, excavation output, and cut soil particle size of the cutter head mounted on the underwater dredging robot under typical preset working conditions (specific conditions include soil cohesion, cutter head lateral speed, cutter head rotation speed, and cutter head burial depth), as shown in Table 2. The soil cohesion used in the following calculations is 150 kPa, and the number of rows of cutter teeth on the cutter head is 6.

[0053] Table 2: Calculation results of the cutter head mathematical model under typical preset working conditions

[0054]

[0055] The cutter head rotation is usually driven by an electric motor or a hydraulic motor. During the dredging of hard soil, the cutting force of the cutter head is large due to the hardness of the soil. In order to reduce the soil particle size and ensure the excavation output, the cutter head rotation speed is often high, which brings a large load to the cutter head system. Therefore, the cutting force of the cutter head is often limited by the structural strength. In this invention, the maximum allowable value of the cutter head power is the rated power of the electric motor or hydraulic motor.

[0056] (3) Relationship between cutter traverse speed, cutter burial depth and excavation output

[0057] Increasing the cutterhead lateral speed increases excavation output, as shown in conditions 1 and 2 of Table 2 above; increasing the cutterhead burial depth also increases excavation output, as shown in conditions 3 and 4 of Table 2 above.

[0058] (4) Maximum allowable value of soil particle velocity

[0059] The auger system to which this invention is applicable has a pipe suction port on the inner side of the auger, which can better draw the mixed slurry into the pipe and reduce leakage. However, due to the influence of the auger's lateral movement speed and rotation speed, the soil particles cut off acquire a velocity as they follow the auger's teeth and are thrown out of the auger. The soil particle velocity is the resultant velocity of the auger's lateral movement speed and the linear velocity of the auger tooth tip. To reduce leakage, the soil particle velocity must be much smaller than the suction port velocity, generally not exceeding 30% of the suction port velocity. The specific formula is as follows:

[0060] V 绞刀齿尖线速度 =2πR*n 绞刀转速 (2)

[0061]

[0062] V 土粒速度 ≤30%V 吸口流速 (4)

[0063] V 吸口流速 =Q 输送流量 / S 吸口面积 (5)

[0064] In equation (2), R is the cutter radius; in equation (5), for the selected dredging equipment, S 吸口面积 It is a constant.

[0065] Example 2, Conveying Parameters

[0066] (1) Critical flow velocity and slurry flow velocity in pipeline transportation

[0067] The critical flow velocity is calculated using the standard formula (JTS181-5-2012), as shown below:

[0068] V c = (90C) V ) 1 / 3 ·g 1 / 4 ·D 1 / 2 ·ω 1 / 2 ·d m -1 / 4 (6)

[0069] Equation (6), V c - Critical flow velocity; C v -Pulp concentration, g-gravitational acceleration; d m Let ω be the diameter of the soil particles and ω be the settling velocity of the sediment particles. The Wushui formula is used for calculation:

[0070]

[0071] In equation (7), ν is the kinematic viscosity coefficient, with a value of 10. -6 m 2 / s; g - gravitational acceleration, taken as 9.8 m / s². 2 ;γ s - The density of solid particles being conveyed, primarily in soil, is taken as 2650 kg / m³. 3 ;γ w - The bulk density of the conveying medium, which is mainly water in this invention, is taken as 1000 kg / m³. 3 .

[0072] The critical flow velocity is directly proportional to the soil particle size (i.e., soil particle diameter). Since the particle size of hard soil is relatively large and its characteristics are different from those of conventional sand and gravel, the critical flow velocity calculated by empirical formula can be used as a reference. The slurry flow velocity needs to be appropriately increased, which can be taken as 1.1-1.5 times the critical flow velocity.

[0073] (2) Mud pump and pipeline matching calculation

[0074] The friction loss is calculated using Wilson's friction calculation formula, as shown below:

[0075]

[0076] In equation (8), I m -Slurry friction loss; I W -Water friction loss; γ m -Solid particle density; γ w -Water density; C vd -Pulp concentration; V m - Slurry flow rate.

[0077] Taking a pipeline with a diameter of 100mm, a spacing (i.e., pipeline length) of 100mm, and a height of 5m as an example, the conveying system is analyzed. After calculating the friction loss using equation (8), the pipeline head loss-flow rate relationship curve is calculated based on the friction loss, and then matched with the head-flow rate characteristic curve of the mud pump. As the conveying concentration increases, the mud pump head gradually decreases, while the pipeline head loss gradually increases. The intersection of the two curves is the operating point at that concentration. Figure 3 As shown. Connecting the operating points to form a curve yields the operating curves that correspond one-to-one with concentration, flow rate, and head, as shown. Figure 4 and Figure 5 As shown, by Figure 4 It can be seen that the matched workflow is 40-120m. 3 / h, that is, the flow rate is 1.42-4.25m / s. Furthermore, the conveying flow rate should be higher than 1.3 times the critical flow rate calculated by equation (6), therefore the conveying flow rate should be higher than 2.1m / s, that is, the flow rate should be higher than 60m³ / h. 3 / h, via Figure 4It can be seen that the corresponding concentration is 22%. Therefore, under this operating condition, the conveying concentration range is 0-22%, and the conveying flow rate range is 60-120 m³ / h. 3 / h.

[0078] In summary, in actual operation, for the selected mud pump and pipeline system, there are suitable transport concentration ranges and transport flow rate ranges during the transportation of hard soil. Within these ranges, the transportation process can be guaranteed to proceed smoothly without clogging.

[0079] For large cutterhead systems, the delivery concentration should be controlled between 15-25%; for small cutterhead systems, the delivery concentration should be controlled between 11-17%. Furthermore, for the selected mud pump, the appropriate pipe length and diameter can be chosen from the operating curve based on the requirements of a wide delivery concentration range and moderate flow rate.

[0080] (3) Relationship between mud pump speed and conveying flow rate

[0081] The same mud pump will have different head-flow characteristic curves when operating at different speeds, according to the proportionality law. The pump speed increases, and the flow rate increases.

[0082] Example 3: Control methods for dredging different hard soils under the cutter suction operation mode

[0083] The above analysis shows that the relationship between cutting parameters and conveying parameters is complex, and they influence and restrict each other. Based on the selected dredging equipment and after performing excavation and conveying matching calculations, key parameters in the dredging process are monitored and controlled. Monitoring parameters include slurry flow velocity, conveying concentration, soil particle velocity, and cutter power in the pipeline; control parameters include cutter rotation speed, cutter lateral speed, cutter burial depth, and mud pump speed. Different control methods are used for the following five abnormal operating states, as detailed below:

[0084] (1) If the slurry flow rate is <1.1*critical flow rate and the delivery concentration is too high, there is a risk of pipe blockage. The pump speed should be increased first to quickly increase the slurry flow rate. Secondly, the cutter lateral movement speed should be reduced to reduce the soil particle size, reduce the critical flow rate, reduce the excavation output, and thus reduce the delivery concentration.

[0085] (2) If the slurry velocity is less than 1.1*critical velocity and the conveying concentration is low, the conveying efficiency will be extremely low and stratification is likely to have occurred. This is mainly due to the large particle size of the soil. Therefore, the cutter speed should be increased first to reduce the particle size of the soil, rather than increasing the pump speed first. Otherwise, the concentration will be further reduced, and the system will always be in an inefficient working state. At the same time, the cutter power should be kept away from the upper limit of the cutter power, and the soil particle velocity should be calculated and kept away from the upper limit of the soil particle velocity to avoid a large amount of omission.

[0086] (3) If the slurry velocity is >1.5*critical velocity and the conveying concentration is too high, it is likely that the soil particles are easy to convey. First, the pump speed should be reduced to reduce energy waste; second, the cutter speed should be reduced to reduce the cutter power and further reduce energy consumption while meeting dredging requirements; finally, the cutter lateral speed can be appropriately reduced to appropriately reduce the conveying concentration and avoid local sudden increase in concentration that could cause pipe blockage.

[0087] (4) If the slurry velocity is higher than 1.5 * critical velocity and the delivery concentration is low, it is mainly due to the low excavation output at this time. First, the cutter lateral movement speed should be increased to increase the output, but at the same time, the cutter power should be kept away from exceeding the upper limit of the cutter power. The soil particle velocity should also be calculated and kept away from exceeding the upper limit of the soil particle velocity to avoid a large amount of omission. Second, the cutter burial depth can be appropriately increased to increase the excavation output. If the slurry velocity is still high after the delivery concentration is increased, it can be adjusted according to the third situation.

[0088] (5) If the cutter power suddenly increases, it is likely due to the sudden hardening of the soil. The cutter lateral speed should be reduced first, and the cutter speed should be increased within the allowable range of cutter power. The soil particle velocity should be calculated and should be kept away from the upper limit of soil particle velocity to avoid a large amount of omission.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A method for controlling the dredging of hard soil under a cutter suction operation mode, characterized in that, The dredging of hard soil in the cutter suction operation mode includes two core steps: excavating hard soil and transporting hard soil. During the excavation of hard soil, the particle size of the cut hard soil is controlled by adjusting the cutting parameters. The particle size of the hard soil further limits the transport parameters during the transport of hard soil. The control method is applicable to equipment that uses cutter heads and mud pumps for dredging operations. The cutting parameters include cutter speed, cutter lateral speed, and cutter burial depth. These cutting parameters, combined with hard soil parameters, are used to calculate excavation output, soil particle size, and cutting force through a mathematical model. The conveying parameters include slurry velocity, conveying concentration, and conveying flow rate. The excavation output is combined with mud pump and pipeline parameters, namely mud pump-flow characteristic curve, mud pump speed, and pipeline length and diameter, and the slurry velocity, conveying concentration, and conveying flow rate are calculated based on empirical formulas. The resultant velocity of the cutterhead's lateral movement velocity and the cutterhead tooth tip linear velocity is the soil particle velocity, and the cutterhead tooth tip linear velocity = 2πR*n 绞刀转速 R is the radius of the cutter head; the parameter of the hard soil is the soil cohesion. The soil particle size The calculation formula is as follows: In equation (1), denoted as tangent traverse speed, n as tangent rotation speed, and m as the number of rows of teeth on the tangent.

2. The method for controlling dredging of hard soil according to claim 1, characterized in that, The same mud pump will have different head-flow characteristic curves when operating at different speeds, according to the proportionality law. As the mud pump speed increases, the conveying flow rate also increases.

3. The method for controlling dredging of hard soil according to claim 1, characterized in that, The control method is applicable to equipment including large-scale cutter systems and small-scale cutter systems; for large-scale cutter systems, the delivery concentration is controlled at 15-25%; for small-scale cutter systems, the delivery concentration is controlled at 11-17%.

4. The method for controlling dredging of hard soil according to claim 3, characterized in that, The large cutterhead system includes a dredging cutter suction vessel, while the small cutterhead system includes an environmentally friendly cutter suction vessel and a cutter suction dredging robot.

5. The method for controlling dredging of hard soil according to claim 3, characterized in that, The upper limit of the soil particle velocity is 30% of the suction inlet velocity, and the specific formula is as follows: In equation (3), Let be the suction area of ​​the pipe inlet inside the cutter head. For the selected dredging equipment, It is a constant.

6. The method for controlling dredging of hard soil according to claim 5, characterized in that, Based on the combination of the conveying concentration and soil particle size, the critical flow velocity is calculated using an empirical formula, and the slurry flow velocity is 1.1-1.5 times the critical flow velocity; at the same time, the cutter is driven by an electric motor or a hydraulic motor, and the cutting force of the cutter is limited by the structural strength. The maximum allowable value of the cutter power is the rated power of the electric motor or hydraulic motor.

7. The method for controlling dredging of hard soil according to claim 6, characterized in that, Based on the selected dredging equipment and after performing excavation and transportation matching calculations, key data during the dredging process are monitored and controlled. The monitoring parameters include the slurry flow rate, transportation concentration, soil particle velocity, and cutter power in the pipeline, while the control parameters include cutter rotation speed, cutter lateral speed, cutter burial depth, and mud pump speed.

8. The method for controlling dredging of hard soil according to claim 7, characterized in that, Different control methods are used in the following five situations: (1) When the slurry flow rate is <1.1*critical flow rate and the delivery concentration is too high, the pump speed should be increased first to quickly increase the slurry flow rate, and then the cutter cross-movement speed should be reduced to reduce the soil particle size and reduce the critical flow rate. This also reduces the excavation output and thus reduces the delivery concentration. (2) When the slurry flow rate is less than 1.1*critical flow rate and the conveying concentration is low, the cutter speed should be increased first and the soil particle size should be reduced. At the same time, the cutter power should be kept away from exceeding the upper limit of power, and the soil particle velocity should be calculated and kept away from exceeding the upper limit of soil particle velocity to avoid a large amount of omission. (3) When the slurry velocity is >1.5*critical velocity and the conveying concentration is too high, first reduce the speed of the mud pump to reduce energy waste; second, reduce the speed of the cutter and reduce the power of the cutter to further reduce energy consumption while meeting the dredging requirements; finally, reduce the lateral movement speed of the cutter to reduce the conveying concentration and avoid local sudden increase in concentration and blockage. (4) When the slurry velocity is >1.5*critical velocity and the delivery concentration is low, first increase the cutter lateral speed to increase excavation output, but at the same time, it is necessary to avoid the cutter power from exceeding the upper limit of power, and calculate the soil particle velocity, and avoid it from exceeding the upper limit of soil particle velocity to avoid a large amount of omission; secondly, increase the cutter burial depth to increase excavation output; if the slurry velocity is still too high after the delivery concentration is increased, then adjust according to the third situation. (5) When the power of the cutter suddenly increases due to the sudden hardening of the soil, the cutter lateral movement speed should be reduced first, and the cutter rotation speed should be increased within the allowable range of the cutter power. The soil particle velocity should be calculated and it should be avoided to exceed the upper limit of the soil particle velocity in order to avoid a large amount of omission.

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