A test method for the failure resistance of rake teeth on both sides of three-dimensional soil cutting

Abstract

The present invention relates to a method for testing the destructive resistance of a rake tooth on both sides of a three-dimensionally cut soil body, and belongs to the technical field of dredging engineering. The method measures the corresponding three-dimensional and two-dimensional cutting resistance of a single rake tooth by conducting three-dimensional cutting experiments and two-dimensional cutting experiments of a single rake tooth at different cutting angles and different cutting depths. The two sets of cutting resistances are then subtracted to obtain the destructive resistance of a single rake tooth on both sides of a three-dimensionally cut soil body. Based on the above experimental data, a relationship between the two-dimensional cutting resistance of a single rake tooth and the destructive resistance of a single rake tooth on both sides of a three-dimensionally cut soil body is established. Based on the existing calculation formula for the two-dimensional cutting resistance of a single rake tooth, a calculation formula for the three-dimensional cutting resistance of a single rake tooth is established. The present invention provides an effective calculation method for the three-dimensional cutting resistance of a single rake tooth, and provides a theoretical basis for the design and construction process of the rake teeth of a drag suction dredger.

Description

Technical Field

[0001] The invention belongs to the technical field of dredging engineering, and in particular relates to a method for testing the damage resistance of two sides of a three-dimensionally cut soil body by rake teeth. Background Art

[0002] The drag head of a trailing suction hopper dredger is the core earth-breaking device. The rake teeth, as the key component directly bearing the workload, are crucial for accurate calculation of their cutting resistance. This provides key parameters for drag head design, enabling the design of tooth strength and shape, improving dredging efficiency and equipment reliability. Furthermore, cutting resistance calculations allow for the scientific selection of construction parameters during construction process development, achieving energy savings and high efficiency.

[0003] However, in the current field of rake head and tooth design for dredging projects, there is a lack of sufficient basis for calculating the cutting resistance of the teeth. Traditional cutting resistance formulas in dredging engineering are limited to theoretically derived two-dimensional cutting resistance formulas, lacking a formula for calculating the three-dimensional cutting resistance of the soil. Furthermore, the calculation of the cutting resistance of the rake teeth is affected by soil parameters such as cohesion and adhesion, as well as cutting angle and cutting depth. Summary of the Invention

[0004] To address the challenges of the existing technology, the present invention provides a method for testing the failure resistance of rake teeth on both sides of soil during three-dimensional cutting. Based on a cutting resistance calculation formula derived from traditional two-dimensional theory, the present invention experimentally obtains the failure resistance on both sides of the soil, and uses this to establish a three-dimensional cutting resistance calculation formula for rake teeth. This provides a testing method for establishing this formula, which can be used to calculate the three-dimensional cutting resistance of rake teeth during rake head design and construction process development, thus filling the gap in the calculation formula for three-dimensional cutting resistance of rake teeth in dredging engineering.

[0005] The present invention is implemented as follows: a method for testing the failure resistance of two sides of a three-dimensionally cut soil body by a rake tooth, comprising the following steps:

[0006] Step 1: Preparation of experimental equipment

[0007] Step 2: Single rake tooth three-dimensional cutting experiment

[0008] First, a soil box filled with experimental soil was fixed on an electric lifting base; the rake teeth equipped with cutting force sensors were fixed to the electric push rod; the height of the electric lifting base was adjusted to set the cutting depth and the travel speed of the rake teeth in the cutting system; a single rake tooth three-dimensional cutting experiment was conducted; and the cutting force sensor was used to obtain the three-dimensional cutting resistance of the single rake tooth during the cutting process. F 3;

[0009] Step 3: Single rake tooth two-dimensional cutting experiment

[0010] First, prepare the soil for cutting by removing excess soil, leaving a certain cutting height of soil equal to the width of the rake teeth. Adjust the height of the electric lifting base to set the cutting depth and the travel speed of the rake teeth in the cutting system. Conduct a two-dimensional cutting experiment with a single rake tooth. Use a cutting force sensor to obtain the two-dimensional cutting resistance of a single rake tooth during the cutting process. F 2;

[0011] Step 4: Calculation of the failure resistance on both sides of the soil when a single rake tooth is cutting

[0012] Subtract the two sets of cutting resistance to obtain the failure resistance of the single rake tooth on both sides of the three-dimensional cutting soil F 1, F 1= F 3- F 2;

[0013] Considering the influence of cutting depth and cutting angle, a linear regression fitting model is used to establish the two-dimensional cutting resistance of a single rake tooth. F 2. Destruction resistance on both sides of the soil body with single rake tooth three-dimensional cutting F 1:

[0014] (1)

[0015] Where, F 1 is the failure resistance of a single rake tooth on both sides of the three-dimensional cutting soil, unit is N; F 2 is the two-dimensional cutting resistance of a single rake tooth, in N; d is the cutting depth, in m; α is the cutting angle in radians; 、 and is a constant coefficient;

[0016] Determine the constant coefficient based on experimental data 、 and The numerical value of .

[0017] In the above technical solution, preferably, the above steps further include:

[0018] Step 5: Establish the single rake tooth three-dimensional cutting resistance formula

[0019] The calculation formula of the two-dimensional cutting resistance of a single rake tooth is as follows:

[0020] (2)

[0021] On the basis of formula (2), the experimental formula (1) is combined to establish the calculation formula of the three-dimensional cutting resistance of a single rake tooth as follows:

[0022] (3)

[0023] Where, F 3 is the three-dimensional cutting resistance of a single rake tooth, in N; F 2 is the two-dimensional cutting resistance of a single rake tooth, in N; F 1 is the failure resistance of a single rake tooth on both sides of the three-dimensional cutting soil, unit is N; β is the shear failure angle, in radians; A is the clay adhesion, unit is Pa; C is the cohesion of clay, in Pa; w is the tooth width of the rake, in m; h b is the height of the rake teeth, in m; α is the cutting angle in radians; d is the cutting depth in m.

[0024] In the above technical solution, preferably, in step one, the experimental device includes a cutting system, a soil box and an electric lifting base; the cutting system is used to perform cutting experiments at different cutting angles and cutting depths on the experimental soil in the soil box, and the soil box is installed on the electric lifting base, which is used to drive the soil box to achieve vertical lifting.

[0025] In the above technical solution, it is further preferred that the cutting system includes a support base, an electric push rod, a cutting force sensor and rake teeth, the electric push rod is installed on the support base, the cutting force sensor is located between the electric push rod and the rake teeth, and is respectively connected to the electric push rod and the rake teeth, and the cutting force sensor is used to measure the cutting resistance of the rake teeth.

[0026] In the above technical solution, it is further preferred that the type and angle of the rake teeth can be changed.

[0027] In the above technical solution, it is further preferred that the soil box is detachable and adopts a layered structure, with two adjacent layers connected by bolts, and the side panels of each layer are detachable, so that a layered soil cutting test can be realized.

[0028] In the above technical solution, it is further preferred that the electric lifting base is lifted and lowered in the vertical direction by a hydraulic rod.

[0029] Compared with the prior art, the present invention has the following advantages and positive effects:

[0030] The present invention provides a method for testing the failure resistance of a rake tooth in three-dimensional cutting of soil on both sides. By conducting three-dimensional and two-dimensional cutting experiments of a single rake tooth at different cutting angles and cutting depths, the three-dimensional and two-dimensional cutting resistance of the single rake tooth are measured. F 3. F 2. Subtract the two sets of cutting resistance to obtain the three-dimensional cutting resistance on both sides of the soilF 1= F 3- F 2. Establish single rake tooth two-dimensional cutting resistance F 2. The three-dimensional cutting resistance of the rake teeth on both sides of the soil F 1; Based on the existing single rake tooth two-dimensional cutting resistance calculation formula, a single rake tooth three-dimensional cutting resistance calculation formula is established. The present invention uses a single rake tooth cutting experiment method to establish a single rake tooth two-dimensional cutting resistance calculation formula. F 2. The three-dimensional cutting resistance of the rake teeth on both sides of the soil F 1, and on the basis of the existing single rake tooth two-dimensional cutting resistance calculation formula, a single rake tooth three-dimensional cutting resistance calculation formula is established, which provides an effective calculation method for the three-dimensional cutting resistance of single rake teeth and provides a theoretical basis for the design of rake teeth of trailing suction dredger. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the structure of a soil cutting experimental device provided by an embodiment of the present invention;

[0032] Figure 2 Schematic diagram of single-tooth three-dimensional cutting provided by an embodiment of the present invention;

[0033] Figure 3 It is a schematic diagram of single rake tooth two-dimensional cutting provided by an embodiment of the present invention.

[0034] In the figure: 1. Cutting system; 11. Support base; 12. Electric push rod; 13. Cutting force sensor; 14. Rake teeth; 2. Electric lifting base; 3. Soil box. DETAILED DESCRIPTION

[0035] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0036] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0038] Example

[0039] See also Figures 1 to 3 The embodiment of the present invention provides a method for testing the failure resistance of the two sides of the three-dimensional cutting soil of the rake teeth. A =20102Pa, clay cohesion C =32163Pa; the dimensions of a single rake tooth in the cutting experiment are 75mm wide × 200mm long, and the three cutting angles are 30 degrees, 45 degrees, and 60 degrees respectively; the cutting force sensor is installed on the rake tooth to measure the cutting resistance of a single rake tooth, with a measuring range of 0~30000N and a sampling frequency of 200Hz; the dimensions of the soil box are 1.2m long × 1m wide × 0.6m high; multiple groups of single rake tooth cutting experiments with different cutting depths are carried out, and the soil cutting depths are 50mm, 100mm, and 150mm respectively.

[0040] The specific working process of this embodiment:

[0041] Step 1: Preparation of experimental equipment

[0042] like Figure 1 As shown, the experimental device includes a cutting system 1, a soil box 3, and an electric lift base 2. The cutting system 1 is used to perform cutting experiments on the test soil in the soil box 3 at different cutting angles and cutting depths. The soil box 3 is mounted on the electric lift base 2, which is used to drive the soil box 3 to achieve vertical lifting.

[0043] The cutting system 1 includes a support base 11, an electric push rod 12, a cutting force sensor 13, and rake teeth 14. The electric push rod 12 is bolted to the support base 11. The cutting force sensor 13 is located between the electric push rod 12 and the rake teeth 14 and is bolted to the electric push rod 12 and the rake teeth 14 respectively. The cutting force sensor 13 is used to measure the cutting resistance of the rake teeth 14. The rake teeth 14 can change the type and angle of the rake teeth. The soil container 3 is removable and adopts a layered structure. Adjacent layers are connected by bolts, and the side panels of each layer are removable, enabling layered soil cutting tests. The electric lifting base 2 is vertically raised and lowered by hydraulic rods.

[0044] 1) The structural dimensions and parameters of the main components of the cutting system 1 are as follows:

[0045] Support base 11: 700mm long × 1200mm wide × 720mm high; the table top of the support base is horizontally arranged side by side with a total of three groups of mounting connection blocks, each group of mounting connection blocks is installed with an electric push rod, and the spacing between two adjacent groups of mounting connection blocks is 262mm;

[0046] Main dimensions and parameters of the electric linear actuator 12: Distance from the center of the linear actuator to the support base: 230mm; Rated thrust: 20,000N; Rated speed: 0.1m / s; Motor power: 4kW; Stroke range: 0.1m~1.6m;

[0047] The main parameters of cutting force sensor 13 are: measuring range 0~30000N, sampling frequency 200Hz;

[0048] The main dimensions of the rake teeth 14 are: 200 mm long × 75 mm wide; the angles of the three rake teeth are 30 degrees, 45 degrees and 60 degrees respectively.

[0049] 2) The main structural dimensions and parameters of the electric lifting base 2 are as follows:

[0050] Table size: length 1.5m × width 1.2m;

[0051] Vertical lifting distance range: 85mm~860mm;

[0052] Rated load: 1500kg.

[0053] 3) The main structural dimensions of the soil container 3 are as follows:

[0054] Internal dimensions of the soil box: length 1.2m × width 1m × height 0.6m;

[0055] Height: 30cm / layer × 2 layers

[0056] Step 2: Single rake tooth three-dimensional cutting experiment

[0057] like Figure 2As shown, first, fix the soil box 3 filled with experimental soil on the electric lifting base 2; fix the 30-degree, 45-degree and 60-degree rake teeth 14 equipped with cutting force sensors 13 to the electric push rod 12 respectively; adjust the height of the electric lifting base 2, and set the heights to 250mm, 300mm and 350mm respectively. At this time, the height differences between the rake teeth and the soil surface are 50mm, 100mm and 150mm respectively, that is, the soil cutting depths are 50mm, 100mm and 150mm respectively; set the travel speed of the electric push rod 12 to 0.1m / s; start the electric push rod 12, and conduct a single rake tooth three-dimensional cutting experiment, and test the single rake tooth three-dimensional cutting resistance during the rake tooth cutting soil process through the cutting force sensor 13. F 3.

[0058] Step 3: Single rake tooth two-dimensional cutting experiment

[0059] like Figure 3 As shown, first, preparations are made for cutting the soil, and excess soil is removed, leaving soil with cutting heights of 50mm, 100mm, and 150mm, which are the same width as the rake teeth 14, respectively; the height of the electric lifting base 2 is adjusted to 250mm, 300mm, and 350mm, respectively. At this time, the height differences between the rake teeth 14 and the soil surface are 50mm, 100mm, and 150mm, respectively, that is, the soil cutting depths are 50mm, 100mm, and 150mm, respectively; the travel speed of the electric push rod 12 is set to 0.1m / s; the electric push rod 12 is started, and a single rake tooth two-dimensional cutting experiment is carried out, and the single rake tooth two-dimensional cutting resistance during the rake tooth cutting soil process is tested by the cutting force sensor 13. F 2.

[0060] Step 4: Calculation of the failure resistance on both sides of the soil when a single rake tooth is cutting

[0061] Subtract the two sets of cutting resistance to obtain the failure resistance of the single rake tooth on both sides of the three-dimensional cutting soil F 1, F 1= F 3- F 2.

[0062] The specific working conditions of the cutting experiment are shown in Table 1 below:

[0063] Table 1 Cutting test conditions

[0064]

[0065] According to the experimental data in Table 1, considering the influence of cutting depth and cutting angle, a linear regression fitting model is used to establish the two-dimensional cutting resistance of a single rake tooth. F 2. Destruction resistance on both sides of the soil body with single rake tooth three-dimensional cutting F 1:

[0066] (4)

[0067] in, F 1 is the failure resistance of a single rake tooth on both sides of the three-dimensional cutting soil, unit is N; F 2 is the two-dimensional cutting resistance of a single rake tooth, in N; d is the cutting depth, in m; α is the cutting angle in radians; 、 and is a constant coefficient;

[0068] Determine the constant coefficient based on experimental data 、 and The numerical value of .

[0069] =38, =-9500 and =0.03. .

[0070] Step 5: Establish the single rake tooth three-dimensional cutting resistance formula

[0071] The calculation formula of the two-dimensional cutting resistance of a single rake tooth is as follows:

[0072] (5)

[0073] Where, F 2 is the two-dimensional cutting resistance of a single rake tooth, in N; β is the shear failure angle, in radians; A is the clay adhesion, in Pa; C is the cohesion of clay, in Pa; w is the tooth width of the rake, in m; h b is the height of the rake teeth, in m; α is the cutting angle in radians; d is the cutting depth in m.

[0074] Formula (5) comes from Sape A. Miedema, THE DELFT SAND, CLAY&ROCK CUTTING MODEL[M], Delft University Press, 2014.

[0075] Wherein, the shear failure angle β, is to use the minimum energy theory to find the angle at which the horizontal cutting resistance of the soil is the minimum. The minimum energy theory is a commonly used method in cutting theory. It will not be elaborated in detail here. For details, please refer to Ni Hongchao; Zhu Guohui; Calculation of shear angle in high-speed cutting process based on minimum energy principle [J]; Journal of Anhui University of Technology (Natural Science Edition); Issue 02, 2014; or, Luo Zhiwen, Zhao Wenxiang, Jiao Li, Gao Shoufeng, Liu Zhibing, Yan Pei, Wang Xibin. Cutting force modeling of curved end milling based on oblique cutting [J]. Journal of Mechanical Engineering, 2016, 52(9): 184-192.

[0076] The clay cohesion C , measured by direct shear test of geotechnical test, based on the standard GB / T50123-2019 geotechnical test method standard.

[0077] The clay adhesion A Measured through adhesion test based on TJT / T 320-96 Dredged Rock and Soil Classification Standard.

[0078] Based on the existing single rake tooth two-dimensional cutting resistance calculation formula (5), the experimental formula (4) is combined to establish the single rake tooth three-dimensional cutting resistance calculation formula (6).

[0079] (6)

[0080] Where, F 3 is the three-dimensional cutting resistance of a single rake tooth, in N; F 2 is the two-dimensional cutting resistance of a single rake tooth, in N; F 1 is the failure resistance of a single rake tooth on both sides of the three-dimensional cutting soil, unit is N; β is the shear failure angle, in radians; A is the clay adhesion, unit is Pa; C is the cohesion of clay, in Pa; w is the tooth width of the rake, in m; h b is the height of the rake teeth, in m; α is the cutting angle in radians; d is the cutting depth in m.

[0081] The present invention conducts single rake tooth three-dimensional cutting experiments and single rake tooth two-dimensional cutting experiments with different cutting angles and cutting depths, and measures the corresponding cutting resistance. F 3. F 2. Calculate the failure resistance on both sides of the soil body cut by a single rake tooth in three dimensions F 1. Establishment F 2 and F1, and based on the existing two-dimensional cutting resistance calculation formula, a three-dimensional cutting resistance calculation formula for a single rake tooth is derived. This method fills the gap in the calculation of three-dimensional cutting resistance of rake teeth, provides an effective way to calculate the three-dimensional cutting resistance of single rake teeth, and also provides theoretical support for the design of rake heads and teeth of trailing suction dredgers.

[0082] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for testing the damage resistance of rake teeth on both sides of soil in three-dimensional cutting, characterized in that: The steps include: Step 1: Preparation of experimental equipment Step 2: Single rake tooth three-dimensional cutting experiment Set the cutting depth and the travel speed of the rake teeth; conduct a single rake tooth three-dimensional cutting experiment; obtain the single rake tooth three-dimensional cutting resistance during the cutting process through the cutting force sensor F 3; Step 3: Single rake tooth two-dimensional cutting experiment Remove excess soil, leaving a certain cutting height of soil equal to the width of the rake teeth; set the cutting depth and the travel speed of the rake teeth; conduct a single rake tooth two-dimensional cutting experiment; obtain the single rake tooth two-dimensional cutting resistance during the cutting process through the cutting force sensor F 2; Step 4: Calculation of the failure resistance on both sides of the soil when a single rake tooth is cutting Subtract the two sets of cutting resistance to obtain the failure resistance of the single rake tooth on both sides of the three-dimensional cutting soil F 1, F 1= F 3- F 2; Considering the influence of cutting depth and cutting angle, a linear regression fitting model is used to establish the two-dimensional cutting resistance of a single rake tooth. F 2. Destruction resistance on both sides of the soil body with single rake tooth three-dimensional cutting F 1: （1） Where, F 1 is the failure resistance of a single rake tooth on both sides of the three-dimensional cutting soil, unit is N; F 2 is the two-dimensional cutting resistance of a single rake tooth, in N; d is the cutting depth, in m; α is the cutting angle in radians; 、 and is a constant coefficient; Determine the constant coefficient based on experimental data 、 and The numerical value of .

2. The method for testing the damage resistance of rake teeth on both sides of three-dimensionally cut soil according to claim 1, characterized in that: The above steps also include: Step 5: Establish the single rake tooth three-dimensional cutting resistance formula The calculation formula of the two-dimensional cutting resistance of a single rake tooth is as follows: （2） On the basis of formula (2), the experimental formula (1) is combined to establish the calculation formula of the three-dimensional cutting resistance of a single rake tooth as follows: （3） Where, F 3 is the three-dimensional cutting resistance of a single rake tooth, in N; F 2 is the two-dimensional cutting resistance of a single rake tooth, in N; F 1 is the failure resistance of a single rake tooth on both sides of the three-dimensional cutting soil, unit is N; β is the shear failure angle, in radians; A is the clay adhesion, in Pa; C is the cohesion of clay, in Pa; w is the tooth width of the rake, in m; h b is the height of the rake teeth, in m; α is the cutting angle in radians; d is the cutting depth in m.

3. The method for testing the failure resistance of rake teeth in three-dimensional cutting of soil on both sides according to claim 1, characterized in that: In step 1, the experimental device includes a cutting system, a soil box and an electric lifting base; the cutting system is used to perform cutting experiments at different cutting angles and cutting depths on the experimental soil in the soil box, and the soil box is installed on the electric lifting base, which is used to drive the soil box to achieve vertical lifting.

4. The method for testing the damage resistance of rake teeth on both sides of three-dimensionally cut soil according to claim 3, characterized in that: The cutting system includes a support base, an electric push rod, a cutting force sensor and rake teeth. The electric push rod is installed on the support base. The cutting force sensor is located between the electric push rod and the rake teeth and is connected to the electric push rod and the rake teeth respectively. The cutting force sensor is used to measure the cutting resistance of the rake teeth.

5. The method for testing the damage resistance of rake teeth on both sides of soil in three-dimensional cutting according to claim 4, characterized in that: The type and angle of the rake teeth can be changed.

6. The method for testing the damage resistance of rake teeth in three-dimensional cutting of soil on both sides according to claim 3, characterized in that: The soil box is detachable and adopts a layered structure. Two adjacent layers are connected by bolts, and the side panels of each layer are detachable.

7. The method for testing the damage resistance of two sides of a three-dimensionally cut soil mass by rake teeth according to claim 3, characterized in that: The electric lifting base is lifted and lowered in the vertical direction by a hydraulic rod.

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