Fitting and establishing method of calculating formula of cutting resistance of single tooth of harrow head in different soil types

Abstract

The present invention relates to a method for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types, and belongs to the technical field of dredging engineering. The method first conducts an underwater cutting experiment of a single rake tooth to measure the cutting resistance of a single rake tooth when cutting soil bodies with different cutting speeds, different cutting depths, different cutting angles, and different standard penetration numbers; then, by sequentially establishing the relationship between a single cutting parameter and the cutting resistance, and the relationship between a comprehensive cutting parameter and the cutting resistance, a calculation formula for the cutting resistance is fitted and established; finally, the calculation formula for the cutting resistance is evaluated and corrected. The present invention provides an experimental method for testing the cutting resistance of a single rake tooth of a rake head with different soil types, and provides steps and methods for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types based on experimental data. The calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types established in this way can provide a theoretical basis and guidance for the design, optimization, and formulation of construction process parameters of the rake tooth.

Description

Technical Field

[0001] The invention belongs to the technical field of dredging engineering, and in particular relates to a fitting and establishing method for a calculation formula of the cutting resistance of a single rake tooth of a rake head with different soil types. Background Art

[0002] The drag head of a trailing suction hopper dredger is the primary earth-breaking tool, with the tines being its load-bearing components. Accurately calculating the cutting resistance of the tines provides key parameters for the design of the dredger, ensuring optimal design of tines' strength and shape, thereby improving dredging efficiency and reliability. Furthermore, during operation, resistance calculations can be used to rationally adjust construction parameters, such as drag head lowering depth and navigation speed, to achieve energy conservation and efficient operations.

[0003] Currently, there is little basis for calculating the cutting resistance of rake teeth in the design of dredging heads and teeth. In particular, there are no readily available calculation methods or formulas for calculating the cutting resistance of teeth in different soil types. Therefore, it is of great significance to establish a method for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth in different soil types, which can be used to calculate the cutting resistance of the rake teeth of a trailing suction hopper dredger. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a method for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types. The method provides a calculation formula for the cutting resistance of a single rake tooth of a rake head and a design process for the rake head and teeth, which can provide a basis for the design of rake heads and teeth.

[0005] The present invention is achieved by a method for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types, comprising the following steps:

[0006] Step 1: Single-tooth cutting experiments under different soil types and cutting conditions, including single-tooth cutting experiments under different cutting speeds, cutting depths, cutting angles, and SPEs;

[0007] Step 2: Establish the relationship between a single cutting parameter and cutting resistance

[0008] According to the experimental results obtained in step 1, the cutting speed is plotted respectively. and cutting resistance , cutting depth and cutting resistance , cutting angle α and cutting resistance , standard penetration number N and cutting resistance The relationship diagram of linear regression and power function fitting models are used to establish fitting relationships, which are 、 、 and , and determine the constant coefficient 、 、 、 、 、 、 and The value of

[0009] Step 3: Establishing the relationship between comprehensive cutting parameters and cutting resistance

[0010] According to the fitting relationship between the above single cutting parameter and cutting resistance, the cutting speed is established. 、 Cutting depth 、 Cutting angle α , standard penetration number N and cutting resistance F The comprehensive relationship of , the fitting formula is as follows:

[0011] (1)

[0012] Where, is the cutting resistance, in kN: is the width of the rake teeth, in m; α is the cutting angle, in radians; is the cutting depth, in m; is the cutting speed, in m / s; N The unit is the standard penetration number of hits; 、 、 、 、 、 and are the model coefficients respectively;

[0013] And determine the model coefficients 、 、 、 、 、 and value.

[0014] In the above technical solution, preferably, after determining the model coefficient, the single rake tooth cutting resistance calculation formula is evaluated and corrected:

[0015] The cutting resistance calculated by the single rake tooth cutting resistance calculation formula (1) under the same cutting conditions is expressed as , and the cutting resistance obtained from the cutting experiment in step 1, recorded as , compare and evaluate the fitting effect of calculation formula (1);

[0016] when The data accounts for ≥30% of the total data volume, and The data accounts for ≥60% of the total data volume, and When the ratio of the data to the total data volume is ≥90%, the calculation formula (1) can be used;

[0017] Otherwise, the model coefficients in step 4 、 、 、 、 、 and Adjustments are made until the calculation formula (1) is available.

[0018] In the above technical solution, preferably, in step 1, the single rake tooth cutting experiment includes:

[0019] Preparation of experimental soil:

[0020] Prepare test soil with certain particle ratio, moisture content, density and SPF that meet the requirements;

[0021] Preparation of experimental setup:

[0022] The experimental device includes a running trolley, a cutting rake device and a soil box; the running trolley can realize variable speed movement in the three directions of x, y and z; the cutting rake device is fixed on the running trolley and is used to carry out cutting experiments with different cutting angles, cutting depths and cutting speeds; the soil box is used to hold experimental soil and adopts a layered structure. The adjacent layers are connected by bolts. The left and right side panels and the front and rear retaining plates of each layer of the soil box are all removable, which can realize layered cutting experiments.

[0023] In the above technical solution, preferably, during the preparation of the test soil, the parameter indicators of the test soil can be changed according to engineering needs, and the standard penetration number of the test soil can be measured through a standard penetration test.

[0024] In the above technical solution, preferably, the cutting rake tooth device consists of a tool holder, a cutting force sensor and rake teeth, and the cutting force sensor is located between the tool holder and the rake teeth to measure the cutting resistance of the rake teeth; the rake teeth can change the type and angle of the rake teeth.

[0025] In the above technical solution, preferably, in step 1, the basic steps of the single rake cutting experiment under different cutting conditions are as follows:

[0026] First, a soil box filled with experimental soil is placed and fixed on the experimental table; a cutting rake device equipped with a cutting force sensor is fixed to the running trolley of the experimental table; the running trolley is raised and lowered, the horizontal x-direction and vertical y-direction positions of the running trolley are adjusted, the thickness of the cutting soil layer is set, and the travel speed of the running trolley is set and set in the z-direction; water is injected into the experimental table so that the water surface submerges the soil box; the running trolley is started, and a single rake tooth underwater cutting experiment is carried out; the cutting resistance of the rake tooth during the cutting process is obtained through the cutting force sensor installed on the rake tooth.

[0027] In the above technical solution, preferably, in step 1:

[0028] The single rake cutting experiment at different cutting speeds is to measure the cutting resistance of the single rake under several groups of different cutting speed conditions by changing the travel speed of the running trolley in the z direction while keeping the cutting soil, cutting angle and cutting depth unchanged.

[0029] In the above technical solution, preferably, in step 1:

[0030] The single rake cutting experiment with different cutting depths is to change the position of the running trolley in the vertical y direction and the thickness of the cutting soil under the condition that the cutting soil, cutting angle and cutting speed remain unchanged, and the cutting resistance of the single rake under several groups of different cutting depths is measured.

[0031] In the above technical solution, preferably, in step 1:

[0032] The single rake cutting experiment with different cutting angles is to change the cutting angle by replacing the rake teeth with different angles while keeping the cutting soil, cutting depth and cutting speed unchanged, and measure the cutting resistance of the single rake teeth under several groups of different cutting angle conditions.

[0033] In the above technical solution, preferably, in step 1:

[0034] The single rake cutting experiment for soils with different SPF blows is to measure the cutting resistance of single rake teeth under several groups of soils with different SPF blows while keeping the cutting angle, cutting depth and cutting speed unchanged.

[0035] The advantages and positive effects of the present invention are:

[0036] The present invention provides a method for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types, and provides steps and methods for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types based on experimental data. The calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types established in this way can provide a theoretical basis and guidance for the design, optimization and formulation of construction process parameters of rake heads and rake teeth. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the structure of the experimental device provided by the embodiment of the present invention;

[0038] Figure 2 1 is a schematic structural diagram of a cutting rake tooth device provided in an embodiment of the present invention;

[0039] Figure 3 The cutting speed provided by the embodiment of the present invention is and cutting resistance relationship diagram;

[0040] Figure 4 is the cutting depth provided by the embodiment of the present invention and cutting resistance relationship diagram;

[0041] Figure 5 is the cutting angle provided by the embodiment of the present invention α and cutting resistance relationship diagram;

[0042] Figure 6 The standard penetration number provided by the embodiment of the present invention N and cutting resistance relationship diagram;

[0043] Figure 7 3 is a comparison chart of cutting resistance obtained under two different conditions provided in an embodiment of the present invention.

[0044] In the figure: 1, rake teeth; 2, cutting force sensor; 3, tool holder;

[0045] A. Running trolley; B. Soil box; C. Experimental table; D. Cutting rake device. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0047] Example

[0048] The embodiment of the present invention provides a method for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a hard clay rake head. The experimental soil parameters prepared for the single rake tooth cutting experiment in the embodiment are as follows:

[0049] The moisture content of the clay used to prepare the three molding soils was 20.8%, 21.2% and 23.7%, respectively, and the density was 1.90 g / cm 3 、1.90g / cm 3 and 19.2g / cm3 The plasticity indexes are 18.3, 18.3 and 19.4 (clay), the liquid indexes are -0.03, 0.01 and 0.06 (hard plastic state), and the standard penetration numbers are 18, 21 and 25 respectively.

[0050] The experimental device structure and parameters of the single rake cutting experiment in the embodiment are as follows:

[0051] like Figure 1 As shown in Figure 1, the experimental device includes a running trolley A, a cutting rake device D, and a soil box B. The running trolley A can achieve variable speed movement in the x, y, and z directions. The cutting rake device D is fixed to the running trolley and is used to conduct cutting experiments with different cutting angles, cutting depths, and cutting speeds. Figure 2 As shown, the cutting rake device D consists of a tool holder 3, a cutting force sensor 2, and rake teeth 1. The cutting force sensor 2 is located between the tool holder 3 and the rake teeth 1 and is used to measure the cutting resistance of the rake teeth. The rake teeth 1 can be changed in type and angle. The soil box B, used to hold the experimental soil, adopts a layered structure, with adjacent layers connected by bolts. The left and right side panels and front and rear retaining plates of each layer of the soil box are removable, allowing for layered cutting experiments.

[0052] The size of a single rake tooth in the cutting experiment is 75 mm wide × 200 mm long, and the angles of the rake teeth are divided into three types: 30 degrees, 45 degrees, and 60 degrees; the cutting force sensor is installed on the rake tooth, with a range of 0~30000N and a sampling frequency of 200Hz; the size of the soil box is 0.6m high × 5m long × 2.2m wide, and each layer is 0.2m high.

[0053] The basic steps and experimental cutting parameters of the single rake cutting experiment under different cutting conditions in the embodiment are as follows:

[0054] Basic experimental steps: First, place and fix the soil box filled with experimental soil on the experimental table; fix the cutting rake device equipped with a cutting force sensor on the tool holder of the running trolley of the experimental table; raise and lower the running trolley, adjust the horizontal x-direction and vertical y-direction position of the running trolley, set the thickness of the cutting soil layer, set the running trolley's travel speed and set it in the z-direction; inject water into the experimental table, and the water surface submerges the surface of the soil box to a depth of 10 cm; start the running trolley and conduct a single rake tooth underwater cutting experiment; obtain the cutting resistance of the rake tooth during the cutting process through the cutting force sensor installed on the rake tooth.

[0055] 1) Single rake cutting experiment at different cutting speeds

[0056] When the standard penetration number of soil cutting is 21, the cutting angle is 45 degrees, and the cutting depth is 110 mm, the cutting resistance of a single rake tooth under several different cutting speed conditions is measured by changing the travel speed of the running trolley in the z direction to 0.5 m / s, 0.8 m / s and 1.3 m / s respectively.

[0057] 2) Single rake cutting experiment at different cutting depths

[0058] When the standard penetration number of soil cutting is 18, the cutting angle is 45 degrees, and the cutting speed is 0.5m / s, the thickness of the cutting soil is changed to 110mm, 130mm and 150mm by changing the vertical y-direction position of the running trolley, and the cutting resistance of a single rake tooth under several groups of different cutting depth conditions is measured.

[0059] 3) Single rake cutting experiment at different cutting angles

[0060] When the standard penetration number of soil cutting is 18, the cutting depth is 110mm and the cutting speed is 1.3m / s, the cutting resistance of a single rake tooth under several different cutting angles is measured by replacing the rake teeth with different angles and changing the cutting angle to 30 degrees, 45 degrees and 60 degrees respectively.

[0061] 4) Single rake cutting experiment on soil with different SPF numbers

[0062] When the cutting angle is 45 degrees, the cutting depth is 90 mm and the cutting speed is 1.3 m / s, the cutting resistance of single rake teeth of several groups of cutting soils with different standard penetration blows are measured by changing the cutting soil with different standard penetration blows, namely 18, 21 and 25 blows.

[0063] The specific implementation steps of the embodiment include:

[0064] Step 1: Single rake cutting experiment under different soil types and cutting conditions, including different cutting speeds , different cutting depths , different cutting angles α , different standard penetration numbers N Single rake cutting experiment for cutting soil;

[0065] Step 2: Establish the relationship between a single cutting parameter and cutting resistance

[0066] According to the experimental results obtained in step 1, the cutting speed is plotted respectively. and cutting resistance , cutting depth and cutting resistance , cutting angle α and cutting resistance , standard penetration number N and cutting resistance The horizontal axes of each relationship diagram are cutting speed 、 Cutting depth 、 Cutting angle α and SPBN N , the vertical axis is the corresponding cutting resistance. The linear regression and power function fitting models are used to establish the fitting relationship, and the linear function and power function relationships between the parameters are found, which are 、 、 and , and determine the constant coefficient 、 、 、 、 、 、 and The value of Figures 3 to 6 shown.

[0067] get 、 、 、 、 、 、 and .

[0068] Step 3: Establishing the relationship between comprehensive cutting parameters and cutting resistance

[0069] According to the fitting relationship between the above single cutting parameter and cutting resistance, the cutting speed is established. 、 Cutting depth 、 Cutting angle α and SPBN N and cutting resistance F The comprehensive relationship of , the fitting formula is as follows:

[0070] (2)

[0071] Where, is the cutting resistance, in kN: is the width of the rake teeth, in m; α is the cutting angle, in radians; is the cutting depth, in m; is the cutting speed, in m / s; N The unit is standard penetration hits, hits; 、 、 、 、 、 and are model coefficients respectively; the model coefficient values ​​are determined by referring to the constant coefficients.

[0072] get 、 、 、 、 、 and ,but

[0073]

[0074] In the embodiment, the evaluation and correction process of the calculation formula of the single rake tooth cutting resistance is as follows:

[0075] The cutting resistance calculated by the single rake tooth cutting resistance calculation formula (2) under the same cutting conditions is expressed as , and the cutting resistance obtained from the cutting experiment in step 1, recorded as , compared with the calculation results of formula (2) after the model coefficient fitting iteration And the experimental results The deviation value is , as shown in Table 1 below. The results are plotted in a comparison chart, with the horizontal axis representing the experimental working point and the vertical axis representing the cutting resistance. The data of each working point are connected to compare the fitting degree of the two curves, as shown in Figure 7 As shown, the fitting effect of the calculation formula (2) is evaluated.

[0076] Table 1 All working conditions of cutting experiment

[0077]

[0078] As can be seen from Table 1, The ratio of data to total data volume = 39%>30%, and The ratio of data to total data volume = 64%>60%, and The ratio of data to the total data volume = 93%>90%, and the calculation formula (1) is applicable.

[0079] In summary, the present invention first conducts underwater cutting experiments with a single tine to measure the cutting resistance of a single tine under different cutting speeds, cutting depths, cutting angles, and STPs. Next, by sequentially establishing relationships between single and combined cutting parameters and cutting resistance, a cutting resistance calculation formula is fitted and established. Finally, this formula is evaluated and optimized.

[0080] This paper not only provides an experimental method for testing the cutting resistance of a single rake tooth in different soil types, but also provides steps and methods for fitting experimental data and establishing a calculation formula for the cutting resistance of a single rake tooth in different soil types. The established calculation formula can provide a theoretical basis and guidance for the design and optimization of rake teeth and the formulation of construction process parameters.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fitting and establishing a calculation formula for the cutting resistance of a single rake tooth of a rake head with different soil types, characterized in that: The steps include: Step 1: Single-tooth cutting experiments under different soil types and cutting conditions, including single-tooth cutting experiments under different cutting speeds, cutting depths, cutting angles, and SPEs; Step 2: Establish the relationship between a single cutting parameter and cutting resistance According to the experimental results obtained in step 1, the cutting speed is plotted respectively. and cutting resistance , cutting depth and cutting resistance , cutting angle α and cutting resistance , standard penetration number N and cutting resistance The relationship diagram of linear regression and power function fitting models are used to establish fitting relationships, which are 、 、 and , and determine the constant coefficient 、 、 、 、 、 、 and The value of Step 3: Establishing the relationship between comprehensive cutting parameters and cutting resistance According to the fitting relationship between the above single cutting parameter and cutting resistance, the cutting speed is established. 、 Cutting depth 、 Cutting angle α , standard penetration number N and cutting resistance F The comprehensive relationship of , the fitting formula is as follows: （1） Where, is the cutting resistance, in kN: is the width of the rake teeth, in m; α is the cutting angle, in radians; is the cutting depth, in m; is the cutting speed, in m / s; N The unit is the standard penetration number of hits; 、 、 、 、 、 and are the model coefficients respectively; And determine the model coefficients 、 、 、 、 、 and value.

2. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 1 is characterized in that: After determining the model coefficient, the calculation formula for the cutting resistance of a single rake tooth is evaluated and revised: The cutting resistance calculated by the single rake tooth cutting resistance calculation formula (1) under the same cutting conditions is expressed as , and the cutting resistance obtained from the cutting experiment in step 1, recorded as , compare and evaluate the fitting effect of calculation formula (1); when The data accounts for ≥30% of the total data volume, and The data accounts for ≥60% of the total data volume, and When the ratio of the data to the total data volume is ≥90%, the calculation formula (1) can be used; Otherwise, for the model coefficients in step 4 、 、 、 、 、 and Adjustments are made until the calculation formula (1) is available.

3. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 1 is characterized in that: In step 1, the single rake cutting experiment includes: Preparation of experimental soil: Prepare test soil with certain particle ratio, moisture content, density and SPF that meet the requirements; Preparation of experimental setup: The experimental device includes a running trolley, a cutting rake device and a soil box; the running trolley can realize variable speed movement in the three directions of x, y and z; the cutting rake device is fixed on the running trolley and is used to carry out cutting experiments with different cutting angles, cutting depths and cutting speeds; the soil box is used to hold experimental soil and adopts a layered structure. The adjacent layers are connected by bolts. The left and right side panels and the front and rear retaining plates of each layer of the soil box are all removable, which can realize layered cutting experiments.

4. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 3 is characterized in that: During the preparation of the test soil, the parameter indexes of the test soil can be changed according to the engineering requirements, and the standard penetration number of the test soil can be measured through a standard penetration test.

5. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 3 is characterized in that: The cutting rake device consists of a tool holder, a cutting force sensor and rake teeth. The cutting force sensor is located between the tool holder and the rake teeth and is used to measure the cutting resistance of the rake teeth. The rake teeth can change the type and angle of the rake teeth.

6. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 1 is characterized in that: In step 1, the basic steps of the single rake cutting experiment under different cutting conditions are as follows: First, a soil box filled with experimental soil is placed and fixed on the experimental table; a cutting rake device equipped with a cutting force sensor is fixed to the running trolley of the experimental table; the running trolley is raised and lowered, the horizontal x-direction and vertical y-direction positions of the running trolley are adjusted, the thickness of the cutting soil layer is set, and the travel speed of the running trolley is set and set in the z-direction; water is injected into the experimental table so that the water surface submerges the soil box; the running trolley is started, and a single rake tooth underwater cutting experiment is carried out; the cutting resistance of the rake tooth during the cutting process is obtained through the cutting force sensor installed on the rake tooth.

7. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 1, characterized in that: In the step 1: The single rake cutting experiment at different cutting speeds is to measure the cutting resistance of the single rake under several groups of different cutting speed conditions by changing the travel speed of the running trolley in the z direction while keeping the cutting soil, cutting angle and cutting depth unchanged.

8. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 1 is characterized in that: In the step 1: The single rake cutting experiment with different cutting depths is to change the position of the running trolley in the vertical y direction and the thickness of the cutting soil under the condition that the cutting soil, cutting angle and cutting speed remain unchanged, and the cutting resistance of the single rake under several groups of different cutting depths is measured.

9. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 1, characterized in that: In the step 1: The single rake cutting experiment with different cutting angles is to change the cutting angle by replacing the rake teeth with different angles while keeping the cutting soil, cutting depth and cutting speed unchanged, and measure the cutting resistance of the single rake teeth under several groups of different cutting angle conditions.

10. The method for fitting and establishing a calculation formula for the cutting resistance of a single tooth of a rake head with different soil types according to claim 1, characterized in that: In the step 1: The single rake cutting experiment for soils with different SPF blows is to measure the cutting resistance of single rake teeth under several groups of soils with different SPF blows while keeping the cutting angle, cutting depth and cutting speed unchanged.

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