Tunneling machine anti-mud material and preparation method and tunneling machine

Abstract

The application provides a tunnel boring machine anti-mud material, a preparation method thereof and a tunnel boring machine. The tunnel boring machine anti-mud material comprises an abrasion-resistant base and at least one hydrophobic coating layer; the surface of the abrasion-resistant base has an abrasion-resistant reticular structure, and the hydrophobic coating layer is arranged in the mesh hole of the abrasion-resistant reticular structure; wherein the raw material of the hydrophobic coating layer comprises 97.0-99.7% of a hydrophobic polymer material and 0.3-3.0% of graphene in terms of mass percentage. The application also provides a preparation method of the tunnel boring machine anti-mud material and a tunnel boring machine provided with the tunnel boring machine anti-mud material. The abrasion-resistant reticular structure and the hydrophobic coating layer are adopted, the adhesion resistance and the abrasion resistance are considered, the adhesion of the spoil can be effectively reduced, the damage of the equipment caused by the adhesion can be avoided, and the construction efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction equipment technology, and in particular to an anti-mud-caking material for tunnel boring machines and its preparation method. Background Technology

[0002] During the excavation of underground engineering projects, tunnel boring machines (TBMs) primarily rely on the rotation of the cutterhead to drive the cutterhead's rollers and other cutting tools to crush the working face and break rock. Therefore, the efficiency of rock breaking and the speed of muck removal significantly impact tunnel construction efficiency. When facing highly adhesive geological formations such as clay and mudstone, the TBM cutterhead, cutter box, rollers, and muck chutes are prone to soil and debris adhesion, leading to decreased rock breaking and muck removal speeds, increased torque and thrust, and cutter wear. This can result in serious equipment damage, and in water-rich strata, it may even induce geysers or surface collapses, causing severe engineering accidents.

[0003] Currently, the main methods for preventing soil adhesion between the tunnel boring machine (TBM) cutterhead and excavated material are manual cleaning, high-pressure water cleaning, or soil amendments such as adding foam or bentonite to improve fluidity, or adding oxidants or acidic solutions. These methods are not only costly and time-consuming, but also potentially pollute the environment. Preventing soil adhesion to the TBM surface would reduce cleaning time and costs, and minimize the impact on construction efficiency. Current methods for preventing soil adhesion mainly involve increasing the cutterhead opening ratio, adjusting operating parameters, and applying coatings to reduce the coefficient of friction. However, these methods have limited adjustment ranges, and excessively high opening ratios can reduce the rigidity and reliability of the cutterhead, potentially decreasing construction efficiency, thus limiting their effectiveness. Therefore, it is essential to research and develop a new anti-sludge material and preparation method for TBMs. Summary of the Invention

[0004] To address the problem of reduced construction efficiency caused by adhesion of adhesive rock debris to tunnel boring machines during excavation and muck removal, the present invention aims to propose an anti-mud-caking material for tunnel boring machines and its preparation method.

[0005] To achieve the above objectives, the present invention provides a material for preventing mud caking in tunnel boring machines, comprising a wear-resistant substrate and at least one hydrophobic coating layer;

[0006] The surface of the wear-resistant substrate has a wear-resistant mesh structure, and the hydrophobic coating is disposed within the mesh of the wear-resistant mesh structure;

[0007] The hydrophobic coating comprises, by mass percentage, 97.0-99.7% hydrophobic polymer material and 0.3-3.0% graphene.

[0008] The anti-mud-caking material for tunnel boring machines provided by this invention is generally a sheet-like structure, but it is not limited to a flat surface. It can also be a curved surface or an irregular surface to adapt to the usage requirements of different parts of the tunnel boring machine.

[0009] In the aforementioned anti-mud-caking material for tunnel boring machines, preferably, by mass percentage, the wear-resistant steel used in the wear-resistant base comprises: C, 0.36-0.45%, Si, 0.1-0.6%, Mn, 0.1-0.8%, P, 0.01-0.04%, S, 0.01-0.03%, Cr, 12-14%, Ni, 0.1-0.6%, with the balance being Fe.

[0010] In the aforementioned anti-mud-caking materials for tunnel boring machines, preferably, the depth of the wear-resistant mesh structure is 0.3-1.0 mm. If the depth of the mesh structure is too small, wear will easily occur; if the depth of the mesh structure is too large, the hydrophobic effect will be weakened.

[0011] In the aforementioned anti-mud-caking material for tunnel boring machines, preferably, the mesh size of the mesh structure is 0.1-0.5 mm. If the mesh size is too large, coarse soil particles will directly contact the hydrophobic material and cause wear, reducing the hydrophobic effect; if the mesh size is too small, fine soil particles will easily adhere to the mesh structure.

[0012] In the aforementioned anti-mud-caking materials for tunnel boring machines, preferably, the mesh spacing of the wear-resistant mesh structure is 0.2-0.6 mm. If the spacing is too small, wear is likely to occur; if the spacing is too large, fine soil particles are likely to adhere to the mesh spacing.

[0013] In the aforementioned anti-mud-caking material for tunnel boring machines, preferably, the alloy powder used to prepare the wear-resistant mesh structure comprises, by mass percentage:

[0014] C, 0.20-0.40%, Si, 1.1-1.4%, Mn, 0.3-0.9%, Mo, 0.2-0.8%, Cr, 12-14%, Ni, 0.2-0.6%, balance Fe.

[0015] In the aforementioned anti-mud-caking materials for tunnel boring machines, preferably, the hydrophobic polymer includes polytetrafluoroethylene (PTFE) and / or polyethylene, etc. PTFE possesses excellent chemical stability, high and low temperature resistance, an extremely low coefficient of friction, good lubrication performance, and high hydrophobicity; however, PTFE has low hardness and poor wear resistance. Graphene has high specific strength and can generate a self-lubricating film within PTFE, improving its wear resistance.

[0016] In the aforementioned anti-mud-caking materials for tunnel boring machines, preferably, the thickness of the hydrophobic coating is 5-20 μm. When two or more hydrophobic coatings are provided, the thickness of each hydrophobic coating layer can be controlled to be 5-20 μm.

[0017] In the above-mentioned anti-mud-caking materials for tunnel boring machines, preferably, the surface contact angle of the anti-mud-caking material for tunnel boring machines is 103°-108°.

[0018] The anti-caking material for tunnel boring machines (TBMs) of this invention mainly comprises a wear-resistant mesh structure on a substrate and a hydrophobic coating, with the coating primarily located within the mesh openings of the mesh structure. In the excavated soil produced by a TBM, coarse particles have poor adhesion but high abrasiveness, while fine particles have poor abrasiveness but are prone to adhesion. The anti-caking material for TBMs of this invention can be installed on parts of the TBM that come into contact with adhesive strata such as clay and mudstone. During use, the raised portions of the wear-resistant mesh structure can withstand wear, while the hydrophobic material on the substrate prevents soil adhesion. It balances high wear resistance and hydrophobicity for soil particles of different sizes, preventing adhesion and providing a long service life.

[0019] This invention also provides a method for preparing the above-mentioned anti-mud-caking material for tunnel boring machines, which includes the following steps:

[0020] A wear-resistant mesh structure is formed on the surface of a wear-resistant substrate using laser cladding.

[0021] The raw material for the hydrophobic coating is sprayed into the mesh of the wear-resistant mesh structure to form a hydrophobic coating, thereby obtaining the anti-mud-caking material for the tunnel boring machine.

[0022] In the above preparation method, preferably, the particle size of the alloy powder used in the laser cladding is 45-100 μm.

[0023] In the above preparation method, preferably, the process parameters of the laser cladding include: laser power of 0.5kW, laser scanning speed of 300mm / min, and protective gas of argon.

[0024] In the above preparation method, preferably, the spraying is performed by air spraying, ultrasonic spraying, or electrostatic spraying; more preferably, air spraying is used, with a nozzle diameter of 3-10 mm and a spray gun pressure of 5-15 kg / cm². 2 .

[0025] In the above preparation method, the spraying time can be determined according to the actual spraying situation, and the preferred single-pass spraying time is about 30 seconds. After the paint is sprayed, the material is cured at 80°C for 120 minutes and then removed.

[0026] According to a specific embodiment of the present invention, preferably, the preparation method of the above-mentioned anti-caking material for tunnel boring machines includes the following specific steps:

[0027] Step 1: Using wear-resistant steel as a base, sandblast the surface of the wear-resistant steel to remove the surface oxide layer and contaminants.

[0028] Step 2: A mesh structure is fabricated on the substrate using laser cladding. The alloy powder used has a particle size of 45-100 μm; the laser power is 0.5 kW; the laser scanning speed is 300 mm / min; and the protective gas is argon. After laser cladding, the mesh structure and the substrate are polished with sandpaper to remove the iron oxide scale.

[0029] Step 3: Preparation of polytetrafluoroethylene composite coating: Add graphene to polytetrafluoroethylene emulsion and stir for 5 minutes to disperse evenly to obtain polytetrafluoroethylene composite coating.

[0030] Step 4: Apply the polytetrafluoroethylene composite coating to the substrate and wear-resistant mesh structure using a spraying method, such as air spraying, ultrasonic spraying, or electrostatic spraying; air spraying is preferred, with a nozzle diameter of 3-10mm and a spray gun pressure of 5-15kg / cm². 2 The desired dry film thickness is 5-20 μm. The spraying time is determined based on actual spraying conditions, with each coat taking approximately 30 seconds. After spraying, the coating is cured at 80℃ for 120 minutes before being removed, yielding the anti-mud-caking material for the tunnel boring machine.

[0031] The present invention also provides a tunnel boring machine, wherein the parts of the tunnel boring machine that come into contact with adhesive strata soil (such as viscous soil, mudstone, etc.) during use are equipped with the aforementioned anti-soil-caking material for the tunnel boring machine.

[0032] According to a specific embodiment of the present invention, preferably, the part in contact with the adhesive stratum slag includes one or more of the following: the feed cutterhead, the cutter box, and the slag chute.

[0033] According to a specific embodiment of the present invention, preferably, the assembly method includes bolt connection, adhesive bonding, welding, etc.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] By adopting the anti-mud-caking material of the tunnel boring machine of the present invention, the adhesion of clay, mudstone and other adhesive strata soil to the cutterhead, cutter box and muck chute of the tunnel boring machine can be avoided or reduced, thereby improving the speed of muck removal and tunneling, improving the efficiency of rock breaking and muck removal, reducing damage to the equipment, and reducing downtime for cleaning caused by the equipment.

[0036] Different sizes of excavated soil have varying effects on the wear and adhesion of parts such as the cutterhead, cutter box, and chute of a tunnel boring machine. Larger excavated soil particles exhibit strong abrasiveness but weak adhesion, while smaller particles exhibit strong adhesion but poor abrasiveness. This invention employs a wear-resistant mesh structure and a hydrophobic coating, balancing adhesion resistance and wear resistance. This effectively reduces excavated soil adhesion, prevents equipment damage caused by adhesion, and improves construction efficiency. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the mesh structure in an embodiment. Detailed Implementation

[0038] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0039] Example 1

[0040] This embodiment provides an anti-mud-caking material for tunnel boring machines, which is prepared through the following steps:

[0041] Step 1: Using wear-resistant steel as the wear-resistant base, sandblast the surface of the wear-resistant steel to remove the surface oxide layer and contaminants;

[0042] The composition of wear-resistant steel, by mass percentage, is as follows: C, 0.36%, Si, 0.1%, Mn, 0.8%, P, 0.01%, S, 0.03%, Cr, 12.0%, Ni, 0.1%, with the balance being Fe.

[0043] Step 2: Use laser cladding to create a mesh structure on the substrate (e.g., Figure 1 (As shown), then use sandpaper to sand the mesh structure and the substrate to remove the iron oxide scale;

[0044] The powder used in the network structure, by mass percentage, has the following composition: C, 0.40%, Si, 1.4%, Mn, 0.9%, Mo, 0.2%, Cr, 12.0%, Ni, 0.2%, with the balance being Fe.

[0045] The powder particle size is 45-100μm, the laser power is 0.5kW, the laser scanning speed is 300mm / min, and the protective gas is argon; the depth of the mesh structure is 0.3mm, the pore size of the mesh structure is 0.1mm, and the mesh spacing is 0.3mm.

[0046] Step 3: Preparation of polytetrafluoroethylene composite coating:

[0047] Graphene was added to the polytetrafluoroethylene emulsion and stirred for 5 minutes to disperse it evenly. The composition of the polytetrafluoroethylene composite coating, by mass percentage, is: polytetrafluoroethylene, 99.7%, and graphene, 0.3%.

[0048] Step 4: Apply the PTFE composite coating to the substrate and wear-resistant mesh structure using a spraying method, such as air spraying, ultrasonic spraying, or electrostatic spraying; air spraying is preferred, with a nozzle diameter of 10mm and a spray gun pressure of 5kg / cm². 2 The desired dry film thickness is 5 μm. The spraying time is determined based on actual spraying conditions, with each coat taking approximately 30 seconds. After spraying, the coating is cured at 80℃ for 120 minutes before being removed, yielding the anti-mud-caking material for the tunnel boring machine.

[0049] Step 5: Assembly: The wear-resistant base coated with PTFE composite coating is assembled onto parts of the tunnel boring machine that are prone to adhesion to slag, such as the cutterhead, cutter box, and chute. Assembly methods can include bolting, gluing, welding, etc.

[0050] Example 2

[0051] This embodiment provides an anti-mud-caking material for tunnel boring machines, which is prepared through the following steps:

[0052] Step 1: Using wear-resistant steel as the wear-resistant base, sandblast the surface of the wear-resistant steel to remove the surface oxide layer and contaminants;

[0053] The composition of wear-resistant steel, by mass percentage, is as follows: C, 0.45%, Si, 0.6%, Mn, 0.1%, P, 0.04%, S, 0.01%, Cr, 14.0%, Ni, 0.6%, with the balance being Fe.

[0054] Step 2: Use laser cladding to create a mesh structure on the substrate (e.g., Figure 1 (As shown), then use sandpaper to sand the mesh structure and the substrate to remove the iron oxide scale;

[0055] The powder used in the network structure, by mass percentage, has the following composition: C, 0.20%, Si, 1.1%, Mn, 0.3%, Mo, 0.8%, Cr, 14.0%, Ni, 0.6%, with the balance being Fe.

[0056] The powder particle size is 45-100μm, the laser power is 0.5kW, the laser scanning speed is 300mm / min, and the protective gas is argon; the depth of the mesh structure is 1.0mm, the pore size of the mesh structure is 0.5mm, and the mesh spacing is 0.6mm.

[0057] Step 3: Preparation of polytetrafluoroethylene composite coating:

[0058] Graphene was added to the polytetrafluoroethylene emulsion and stirred for 5 minutes to disperse it evenly. The composition of the polytetrafluoroethylene composite coating, by mass percentage, is: polytetrafluoroethylene, 97.0%, and graphene, 3.0%.

[0059] Step 4: Apply the polytetrafluoroethylene composite coating to the substrate and the wear-resistant screen using a spraying method, such as air spraying, ultrasonic spraying, or electrostatic spraying; air spraying is preferred, with a nozzle diameter of 3mm and a spray gun pressure of 15kg / cm². 2 The desired dry film thickness is 20 μm. The spraying time was determined based on actual spraying conditions, with each coat taking approximately 30 seconds. After spraying, the coating was cured at 80℃ for 120 minutes before being removed, yielding the anti-mud-caking material for the tunnel boring machine.

[0060] Step 5: Assembly: The wear-resistant base coated with PTFE composite coating is assembled onto parts of the tunnel boring machine that are prone to adhesion to slag, such as the cutterhead, cutter box, and chute. Assembly methods can include bolting, gluing, welding, etc.

[0061] Example 3

[0062] This embodiment provides an anti-mud-caking material for tunnel boring machines, which is prepared through the following steps:

[0063] Step 1: Using wear-resistant steel as the wear-resistant base, sandblast the surface of the wear-resistant steel to remove the surface oxide layer and contaminants;

[0064] The composition of wear-resistant steel, by mass percentage, is as follows: C, 0.38%, Si, 0.4%, Mn, 0.5%, P, 0.03%, S, 0.02%, Cr, 13.2%, Ni, 0.5%, with the balance being Fe.

[0065] Step 2: Use laser cladding to create a mesh structure on the substrate (e.g., Figure 1 (As shown), then use sandpaper to sand the mesh structure and the substrate to remove the iron oxide scale;

[0066] The powder used in the network structure, by mass percentage, has the following composition: C, 0.33%, Si, 1.3%, Mn, 0.7%, Mo, 0.6%, Cr, 13.0%, Ni, 0.4%, with the balance being Fe.

[0067] The powder particle size is 45-100μm, the laser power is 0.5kW, the laser scanning speed is 300mm / min, and the protective gas is argon; the depth of the mesh structure is 0.5mm, the pore size of the mesh structure is 0.3mm, and the mesh spacing is 0.2mm.

[0068] Step 3: Preparation of polytetrafluoroethylene composite coating:

[0069] Graphene was added to the polytetrafluoroethylene emulsion and stirred for 5 minutes to disperse it evenly. The composition of the polytetrafluoroethylene composite coating, by mass percentage, is: 98.3% polytetrafluoroethylene and 1.7% graphene.

[0070] Step 4: Apply the PTFE composite coating to the substrate and wear-resistant mesh structure using a spray gun with a nozzle diameter of 4mm and a spray gun pressure of 10kg / cm². 2 The desired dry film thickness is 18 μm. The spraying time was determined based on actual spraying conditions, with each coat taking approximately 30 seconds. After spraying, the coating was cured at 80℃ for 120 minutes before being removed, yielding the anti-mud-caking material for the tunnel boring machine.

[0071] Step 5: Assembly: The wear-resistant base coated with PTFE composite coating is assembled onto parts of the tunnel boring machine that are prone to adhesion to slag, such as the cutterhead, cutter box, and chute. Assembly methods can include bolting, gluing, welding, etc.

[0072] Comparative Example 1:

[0073] The difference between this comparative example and Example 1 is that the laser cladding process for creating the mesh structure in step 2 is omitted.

[0074] Comparative Example 2:

[0075] The difference between this comparative example and Example 1 is that the steps of preparing and spraying the polytetrafluoroethylene composite coating in steps 3 and 4 are omitted.

[0076] Comparative Example 3:

[0077] The difference between this comparative example and Example 1 is that the steps of laser cladding to create the mesh structure and spraying polytetrafluoroethylene composite coating in steps 2-4 are omitted; only a wear-resistant steel substrate is used.

[0078] Comparative Example 4:

[0079] The difference between this comparative example and Example 1 is that the depth of the mesh structure in step 2 is 1.1 mm, the aperture of the mesh is 0.05 mm, and the mesh spacing is 0.7 mm.

[0080] Comparative Example 5:

[0081] The difference between this comparative example and Example 1 is that the depth of the mesh structure in step 2 is 0.2 mm, the aperture of the mesh structure is 1.0 mm, and the mesh spacing is 0.1 mm.

[0082] The impact wear performance of the coated mesh structure was tested using an impact wear test. Samples of the same size (10mm × 10mm × 30mm) were used for the test. The test parameters were: impact energy 2J, time 2h, impact frequency 100 times / min, abrasive particles quartz sand, and the friction pair for the impact wear test was GCr15 bearing steel with a hardness of 62HRC. Weight loss was measured after the impact wear test. A static contact angle meter was used to measure the surface contact angle of the coated mesh structure to characterize its hydrophobic properties. A 5μl water droplet was measured using a micro-syringe, and measurements were taken from three randomly selected areas on the sample surface. The average value was then calculated. The test results are shown in Table 1.

[0083] Table 1. Test results of wear weight loss and surface contact angle for the examples and comparative examples.

[0084]

[0085]

[0086] According to the experimental results in Table 1, the anti-mud-caking materials for tunnel boring machines prepared in Examples 1-3 have good wear resistance and good hydrophobicity, and can exhibit good anti-mud-caking performance in actual use.

[0087] As shown in Table 1, the surface contact angles of Examples 1-3 and Comparative Example 1 are all >90°, indicating a certain degree of hydrophobicity, which can effectively reduce the adhesion of adhesive materials such as soil and rock debris to the surface. Meanwhile, the wear loss of Examples 1-3 is below 0.35g, significantly lower than that of Comparative Example 1, indicating that the laser cladding mesh structure significantly increases its wear resistance. Comparative Example 3, with only a wear-resistant substrate, has the highest wear loss, a relatively low surface contact angle, and poor anti-adhesion effect. Comparative Example 4 has a larger depth but smaller pore size and larger pore spacing. If the pore size is too small or the pore spacing is too large, fine soil particles can easily adhere to the mesh structure. Comparative Example 5 has a smaller depth but larger pore size and smaller pore spacing. If the pore size of the mesh structure is too large or the pore spacing is too small, coarse soil particles will directly contact the hydrophobic material and wear down, reducing the hydrophobic effect. A lower depth results in slightly weaker wear resistance.

[0088] To compare the anti-caking performance, adhesive mud cake samples were prepared and adhesion tests were conducted. The adhesive mud cake samples were prepared using sand, kaolin, and distilled water in a weight ratio of 4:4:2 and allowed to stand for 24 hours, exhibiting strong adhesion. Example and comparative sample specimens of the same size (500mm × 200mm × 10mm) were selected and placed at a 45° angle to the horizontal. The adhesive mud cake samples were released from the same position above the plate-shaped sample of the examples and comparative examples. The adhesive mud cake samples in Examples 1-3 and Comparative Example 1 could freely slide to the bottom of the plate-shaped sample, while the adhesive mud cake samples in Comparative Examples 2-5 remained essentially still, indicating that Examples 1-3 and Comparative Example 1 possess a certain degree of anti-adhesion effect.

Claims

1. A material for preventing mud caking in tunnel boring machines, comprising a wear-resistant substrate and at least one hydrophobic coating layer; The surface of the wear-resistant substrate has a wear-resistant mesh structure, and the hydrophobic coating is disposed within the mesh of the wear-resistant mesh structure; in, By weight percentage, the raw materials of the hydrophobic coating comprise 97.0-99.7% hydrophobic polymer material and 0.3-3.0% graphene; The wear-resistant mesh structure has a depth of 0.3-1.0 mm, a mesh aperture of 0.1-0.5 mm, and a mesh spacing of 0.2-0.6 mm. The alloy powder used to prepare the wear-resistant mesh structure comprises, by weight percentage: C, 0.20-0.40%, Si, 1.1-1.4%, Mn, 0.3-0.9%, Mo, 0.2-0.8%, Cr, 12-14%, Ni, 0.2-0.6%, balance Fe; The hydrophobic polymer includes polytetrafluoroethylene and / or polyethylene.

2. The anti-mud-caking material for tunnel boring machines according to claim 1, wherein, The wear-resistant steel used in the wear-resistant substrate, by weight percentage, comprises: C, 0.36-0.45%, Si, 0.1-0.6%, Mn, 0.1-0.8%, P, 0.01-0.04%, S, 0.01-0.03%, Cr, 12-14%, Ni, 0.1-0.6%, balance Fe.

3. The anti-mud-caking material for tunnel boring machines according to claim 1, wherein, The thickness of the hydrophobic coating is 5-20 μm.

4. The anti-mud-caking material for tunnel boring machines according to claim 1, wherein, The surface contact angle of the anti-mud-caking material of the tunnel boring machine is 103°-108°.

5. A method for preparing the anti-caking material for tunnel boring machines according to any one of claims 1-4, comprising the following steps: A wear-resistant mesh structure is formed on the surface of a wear-resistant substrate using laser cladding. The raw material for the hydrophobic coating is sprayed into the mesh of the wear-resistant mesh structure to form a hydrophobic coating, thereby obtaining the anti-mud-caking material for the tunnel boring machine.

6. The preparation method according to claim 5, wherein, The spraying is carried out by air spraying, ultrasonic spraying or electrostatic spraying.

7. The preparation method according to claim 6, wherein, The application is done by air spraying, with a nozzle diameter of 3-10mm and a spray gun pressure of 5-15kg / cm². 2 .

8. A tunnel boring machine, wherein, The parts of the tunnel boring machine that come into contact with adhesive strata and excavated soil during use are equipped with the anti-sludge material for the tunnel boring machine as described in any one of claims 1-4.

9. The tunnel boring machine according to claim 8, wherein, The parts in contact with the adhesive strata soil include one or more of the following: the cutterhead, the cutter box, and the chute.

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