A bionic electro-osmotic corrugated structure system of a shield cutter and a method for preventing mud cake from being formed

Abstract

The application provides a system of bionic electro-osmosis corrugated structure of a shield cutter and a method for preventing mud cake, and relates to the technical field of shield construction. The system comprises a shield cutter and an electro-osmosis component connected with the shield cutter. The electro-osmosis component comprises a power supply, a first wire, a second wire and a plurality of crown-covered conductive units. All the crown-covered conductive units are arranged on the shield cutter and are separated from the shield cutter by insulation. All the crown-covered conductive units are connected in parallel on the positive pole of the power supply through the first wire. The shield cutter is connected with the negative pole of the power supply through the second wire. The power supply is arranged on the non-working surface of the shield cutter. The method comprises continuously electrifying the electro-osmosis component during the operation of the shield cutter, so that the thickness of the water film layer is increased to reduce the interaction force between the mud cake soil layer and the working surface of the shield cutter, the mud cake soil layer is facilitated to fall off, and the purpose of preventing mud cake is achieved.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) construction technology, specifically to a biomimetic electroosmotic corrugated structure system for a TBM cutterhead and a method for preventing mud cake from caking. Background Technology

[0002] During tunnel boring machine (TBM) construction, as the cutterhead cuts and compresses the soil, a high-strength mud cake is easily formed at the center of the cutterhead and gradually spreads outwards. This causes the cutterhead and cutting tools to become encased, making it impossible to effectively cut the soil layer and reducing the efficiency of TBM tunneling.

[0003] When a tunnel boring machine (TBM) cutterhead operates on sticky, wet materials, the adhesion of soil to the cutterhead severely reduces its operational efficiency and quality, significantly lowering productivity. However, animals in sticky, wet soil, which also operate on sticky materials, effectively avoid this adhesion problem. Researchers, through extensive observation and surface testing of typical soil animals such as dung beetles, mole crickets, and earthworms, discovered that their bodies generally exhibit geometrically non-smooth features. Specifically, structural units of certain geometric shapes are randomly or regularly distributed on certain parts of their bodies, with shapes including scale-like, convex, and wavy forms. Researchers at Jilin University of Technology, from a biomimetic perspective, studied the anti-adhesion mechanisms and detachment patterns of typical soil animals living in highly adhesive soil. Their results indicate that the non-smooth structure of the soil animal's body surface and its bio-electro-osmotic system are important factors in reducing adhesion and removing soil. In other words, the application of biomimetic principles to mechanical soil de-adhesion has achieved good results.

[0004] Soil can be considered as a dispersion composed of soil particles, water, and air. Based on the surface energy theory of contact surfaces, Qian Dinghua proposed a five-layer interface model. See also Figure 1 In the five-layer interface model, the adhesion interface is divided into five layers. Interface A1 is the metal interface; interface A2 is the interface between the metal and the water film layer; interface A3 is the water film layer; interface A4 is the interface between the water film and soil particles; and interface A5 is the soil layer. When relative slippage occurs between the soil layer and the metal, the failure at the bond between the soil layer and the metal does not occur within the soil particles themselves. The external force serves two purposes: firstly, it divides an interface layer into two surfaces; secondly, it overcomes the attractive force between the metal surface and the soil particles caused by the water film layer, primarily focusing on the latter. According to the five-layer interface model, the magnitude of the adhesion force largely depends on the weakest interface layer. Because the water film layer structure is looser than the other structural layers, the magnitude of this attractive force is largely related to the thickness of the water film layer. When the thickness of the water film layer is small, it is insufficient to form a free liquid surface; in this case, the interaction force between the soil layer and the metal surface is strong.

[0005] Therefore, it is of great significance to provide a shield cutterhead biomimetic electroosmotic corrugated structure system and a mud cake anti-caking method that can increase the thickness of the water film layer to reduce the interaction force between the soil layer and the metal surface. Summary of the Invention

[0006] To address the problems in existing technologies, the present invention aims to provide a biomimetic electroosmotic corrugated structure system for a tunnel boring machine (TBM) cutterhead and a method for preventing mud cake formation. On one hand, mimicking the electroosmotic phenomenon on biological surfaces, the invention solves the separation problem of positive and negative electrodes by setting convex crown-shaped conductive units on the TBM cutterhead. Then, by setting a power source, electroosmosis increases the thickness of the water film between the TBM cutterhead working surface and soil particles, achieving the effect of reducing adhesion, lowering resistance, and preventing mud cake formation. Simultaneously, the multiple convex crown-shaped conductive units on the TBM cutterhead working surface create a non-smooth surface, further reducing adhesion and achieving the goal of preventing mud cake formation. On the other hand, mimicking the geometric non-smooth characteristics of soil biological surfaces, the surface of the TBM cutterhead panel is modified by setting a series of regularly spaced corrugated structural units, which further reduces adhesion and achieves the goal of preventing mud cake formation.

[0007] The specific technical solution is as follows:

[0008] In a first aspect, the present invention provides a biomimetic electroosmotic corrugated structure system for a tunnel boring machine cutterhead, comprising a tunnel boring machine cutterhead and an electroosmotic component connected to the tunnel boring machine cutterhead;

[0009] The electroosmosis assembly includes a power supply, a first conductor, a second conductor, and multiple convex crown conductive units. All convex crown conductive units are arranged on the shield cutterhead and are separated from the shield cutterhead by insulating components. All convex crown conductive units are connected in parallel to the positive terminal of the power supply through the first conductor. The shield cutterhead is connected to the negative terminal of the power supply through the second conductor. The power supply is located on the non-working surface of the shield cutterhead.

[0010] Optionally, each crown-shaped conductive unit may include multiple crown-shaped conductive elements connected in parallel.

[0011] Optionally, in each crown-shaped conductive unit, multiple connecting wires of all crown-shaped conductive elements are wound into a single strand and connected to a junction box, and then connected in parallel to the positive terminal of the power supply via a first wire.

[0012] Optionally, the conductive component of the crown includes a crown end and an insertion end connected together. The crown end is disposed on the working surface of the shield cutterhead and is separated from the shield cutterhead by an insulating component. A reserved through hole is provided on the shield cutterhead, and the insertion end passes through the reserved through hole and is separated from the reserved through hole by an insulating component at the connection point.

[0013] Optionally, the conductive component of the convex crown package further includes a conductive locking component, and a mounting hole adapted to the conductive locking component is provided on the insertion end; one end of the conductive locking component is a conductive locking end, which is locked in the mounting hole, while the other end is a conductive exposed end, which is connected in parallel to the positive terminal of the power supply through a connecting wire and a first wire; the contact point between the conductive exposed end of the conductive locking component and the shield cutterhead is separated by an insulating component.

[0014] Optionally, the electroosmosis component also includes multiple indicator lights, each of which is located on the non-working surface of the shield cutterhead and is connected in series with the conductive element of the convex crown via connecting wires.

[0015] Optionally, multiple protruding corrugated structural units are provided on the exposed working surface of the shield cutterhead; all corrugated structural units are arranged in a regular pattern.

[0016] Optionally, the ratio of the working surface area occupied by all the conductive units of the convex crown on the shield cutterhead to the exposed working surface area on the shield cutterhead is 0.01-0.2.

[0017] Optionally, the insulating element includes an insulating ring and an insulating gasket.

[0018] In a second aspect, the present invention provides a method for preventing mud cake from caking using the aforementioned biomimetic electroosmotic corrugated structure system of the tunnel boring machine cutterhead, comprising:

[0019] Step S1: Before the shield cutterhead is operated, the electroosmotic component is energized so that the conductive unit of the crown is positively charged and the working face of the shield cutterhead is negatively charged.

[0020] Step S2: Start the operation of the shield cutterhead. During the operation of the shield cutterhead, the electroosmosis component is continuously energized.

[0021] Step S3: After the shield cutterhead operation is completed, the power to the electroosmosis component is turned off.

[0022] The application of the technical solution of the present invention has at least the following beneficial effects:

[0023] This invention provides a biomimetic electroosmotic corrugated structure system for a tunnel boring machine (TBM) cutterhead. When the TBM assembly operates on the soil, mud cake easily forms on the cutterhead's working surface. The electroosmotic assembly makes the conductive units of the convex crowns positively charged, while the cutterhead working surface is negatively charged. Water molecules in the mud cake layer exist as hydrated cations, carrying a positive charge, and easily accumulate towards the negatively charged cutterhead working surface, forming a water film layer. Under the continuous energization of the electroosmotic assembly, the thickness of the water film layer increases, reducing the interaction force between the mud cake layer and the cutterhead working surface, facilitating the detachment of the mud cake layer and achieving the purpose of preventing mud cake formation. Simultaneously, the multiple conductive units of the convex crowns on the cutterhead working surface create a non-smooth surface, further reducing adhesion and achieving the purpose of preventing mud cake formation. Furthermore, surface modification of the cutterhead panel, incorporating a series of regularly spaced corrugated structural units, further reduces adhesion and achieves the purpose of preventing mud cake formation.

[0024] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the five-layer interface model in the background technology of this invention;

[0027] Figure 2 This is a schematic diagram of the structure of the electroosmosis component in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the conductive component of the convex crown package installed on the shield cutterhead in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the conductive component of the convex crown and the shield cutterhead before installation in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of a pre-reserved through hole on the shield cutterhead in an embodiment of the present invention;

[0031] Figure 6 This is an enlarged view of the corrugated structural unit set on the shield cutterhead in an embodiment of the present invention;

[0032] Among them, 1. Power supply, 2. First conductor, 3. Shield cutterhead, 3.1 Reserved through hole, 4. Convex crown conductive single piece, 4.1 Convex crown end, 4.2 Insertion end, 5. Connecting conductor, 6. Junction box, 7. Conductive locking piece, 7.1 Conductive locking end, 7.2 Conductive exposed end, 8. Insulating gasket, 9. Insulating ring, 10. Indicator light, 11. Corrugated structure unit. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0034] Example:

[0035] See Figure 1-6 A biomimetic electroosmotic corrugated structure system for a tunnel boring machine cutterhead includes a tunnel boring machine cutterhead and an electroosmotic component connected to the tunnel boring machine cutterhead;

[0036] The electroosmosis assembly includes a power supply 1, a first conductor 2, a second conductor, and four convex crown conductive units. All convex crown conductive units are arranged on the shield cutterhead 3 and are separated from the shield cutterhead 3 by insulating components. All convex crown conductive units are connected in parallel to the positive terminal of the power supply 1 through the first conductor 2. The shield cutterhead 3 is connected to the negative terminal of the power supply 1 through the second conductor. The power supply 1 is located on the non-working surface of the shield cutterhead 3.

[0037] See Figure 2 Each convex crown conductive unit includes ten parallel convex crown conductive elements 4. The parallel circuit structure for each convex crown conductive element 4 facilitates individual control of each element. Even if one element 4 malfunctions, it will not affect the operation of the others, thus improving the reliability of the electroosmotic module.

[0038] See Figure 2 In each convex crown conductive unit, multiple connecting wires 5 of all convex crown conductive units 4 are wound into a single strand and connected to a junction box 6. The wires are connected in parallel to the positive terminal of the power supply 1 through the first wire 2. The junction box 6 is used to provide waterproofing for the wires.

[0039] See Figure 2The electroosmosis component also includes multiple indicator lights 10, each of which is located on a non-working surface of the shield cutterhead 3 and is connected in series with each of the convex crown conductive components 4 via connecting wires 5. The indicator lights 10 are used to determine the working status of a single convex crown conductive component 4. If an indicator light 10 goes out while the shield cutterhead is working normally, it indicates that a certain convex crown conductive component 4 is malfunctioning and can be replaced promptly.

[0040] See Figure 3-4 The conductive component 4 with a raised crown includes a connected raised crown end 4.1 and an insertion end 4.2. The raised crown end 4.1 is disposed on the working surface of the shield cutterhead 3 and is separated from the shield cutterhead 3 by an insulating component (specifically an insulating gasket 8). A reserved through hole 3.1 is provided on the shield cutterhead 3. The insertion end 4.2 penetrates the reserved through hole 3.1 and is separated from the reserved through hole 3.1 by an insulating component (specifically an insulating ring 9) at the connection point.

[0041] See Figure 3-4 The conductive component 4 of the convex crown also includes a conductive locking component 7 (specifically a bolt made of conductive material). An installation hole adapted to the conductive locking component 7 is provided on the insertion end 4.2. One end of the conductive locking component 7 is a conductive locking end 7.1, which is locked in the installation hole, while the other end is a conductive exposed end 7.2, which is connected in parallel to the positive terminal of the power supply 1 through a connecting wire 5 and a first wire 2. The contact point between the conductive exposed end 7.2 of the conductive locking component 7 and the shield cutterhead 3 is separated by an insulating component (specifically an insulating gasket 8).

[0042] See Figure 5-6 Multiple corrugated structural units 11 are provided on the exposed working surface of the shield cutterhead 3; all the corrugated structural units 11 are arranged in a regular manner, so that the exposed working surface of the shield cutterhead has geometric non-smooth characteristics, which helps to reduce adhesion and achieve the purpose of preventing mud cake.

[0043] The corrugated structural unit 11 is fitted to the front part of the contracted state curve of an earthworm's head. The curve coordinate points are extracted, and the curve is fitted using MATLAB software. The curve fitting equation is y = 0.2293 - 0.2193cos(2r) + 0.1331sin(2r). The contracted state curve of the earthworm's head is applied to the exposed working surface of the shield cutterhead to achieve surface reshaping. r represents the distance of a point E on the exposed working surface of the shield cutterhead from the center of the shield cutterhead, and y represents the protrusion height of the corrugated structural unit 11 at point E. All the corrugated structural units are arranged in a regular pattern.

[0044] The ratio of the working surface area occupied by all the conductive units of the convex crown on the shield cutterhead 3 to the exposed working surface area on the shield cutterhead 3 is 0.01-0.2. In this embodiment, 0.1 is preferred.

[0045] In this embodiment, different structural forms of the shield cutterhead 3 can be selected depending on the experimental conditions.

[0046] A method for preventing mud cake caking using the aforementioned biomimetic electroosmotic corrugated structure system of the tunnel boring machine cutterhead includes:

[0047] Step S1: Before the shield cutterhead 3 is operated, the electroosmosis component is energized so that the conductive unit of the crown is positively charged and the working face of the shield cutterhead is negatively charged.

[0048] Step S2: Start the operation of the shield cutterhead 3. During the operation of the shield cutterhead, the electroosmosis component is continuously energized.

[0049] Step S3: After the operation of the shield cutterhead 3 is completed, the power to the electroosmosis component is turned off.

[0050] The principle behind the shield cutterhead biomimetic electroosmotic corrugated structure system for preventing mud cake is as follows:

[0051] When the shield tunneling components operate on the soil, mud cake easily forms on the working surface of the cutterhead 3. The electroosmotic components, by making the conductive units of the convex crowns positively charged and the working surface of the cutterhead 3 negatively charged, address this issue. Water molecules in the mud cake layer exist as hydrated cations, carrying a positive charge, and readily aggregate towards the negatively charged working surface of the cutterhead 3, forming a water film. With continuous energization from the electroosmotic components, the thickness of the water film increases, reducing the interaction force between the mud cake layer and the working surface of the cutterhead 3, facilitating the shedding of the mud cake layer and preventing mud cake formation. Simultaneously, the multiple conductive units of the convex crowns on the working surface of the cutterhead 3 create a non-smooth surface, further reducing adhesion and preventing mud cake formation. Furthermore, mimicking the geometric non-smooth characteristics of soil biological surfaces, the cutterhead panel is surface-modified with a series of regularly shaped corrugated structural units 11, which further reduces adhesion and prevents mud cake formation.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A biomimetic electroosmotic corrugated structure system for a tunnel boring machine cutterhead, characterized in that, This includes the shield cutterhead and the electroosmosis assembly connected to the shield cutterhead; The electroosmosis assembly includes a power supply (1), a first conductor (2), a second conductor, and multiple convex crown conductive units. All convex crown conductive units are arranged on the shield cutterhead (3) and are separated from the shield cutterhead (3) by insulating parts. All convex crown conductive units are connected in parallel to the positive terminal of the power supply (1) through the first conductor (2). The shield cutterhead (3) is connected to the negative terminal of the power supply (1) through the second conductor. The power supply (1) is located on the non-working surface of the shield cutterhead (3). Each crown-shaped conductive unit includes multiple parallel crown-shaped conductive elements (4); In each convex crown conductive unit, multiple connecting wires (5) of all convex crown conductive units (4) are wound into a single wire and connected to the junction box (6), and connected in parallel to the positive terminal of the power supply (1) through the first wire (2); The conductive component (4) with a raised crown includes a connected raised crown end (4.1) and an insertion end (4.2). The raised crown end (4.1) is located on the working surface of the shield cutterhead (3) and is separated from the shield cutterhead (3) by an insulating component. A reserved through hole (3.1) is provided on the shield cutterhead (3). The insertion end (4.2) passes through the reserved through hole (3.1) and is separated from the reserved through hole (3.1) by an insulating component at the connection point. The conductive single component (4) of the convex crown also includes a conductive locking component (7), and an installation hole adapted to the conductive locking component (7) is provided on the insertion end (4.2); one end of the conductive locking component (7) is a conductive locking end (7.1), which is locked in the installation hole, while the other end is a conductive exposed end (7.2), which is connected in parallel to the positive terminal of the power supply (1) through a connecting wire (5) and a first wire (2); the contact point between the conductive exposed end (7.2) of the conductive locking component (7) and the shield cutterhead (3) is separated by an insulating component; Multiple corrugated structural units (11) are provided on the exposed working surface of the shield cutterhead (3); all the corrugated structural units (11) are arranged in a regular pattern. The ratio of the working surface area occupied by all the conductive units of the convex crown on the shield cutterhead (3) to the exposed working surface area on the shield cutterhead (3) is 0.01-0.

2.

2. The shield cutterhead biomimetic electroosmotic corrugated structure system according to claim 1, characterized in that, The electroosmosis component also includes multiple indicator lights (10), each of which is located on the non-working surface of the shield cutterhead (3) and is connected in series with the conductive single piece (4) of the convex crown bag through connecting wires.

3. The shield tunnel cutterhead biomimetic electroosmotic corrugated structure system according to claim 2, characterized in that, The insulating component includes an insulating ring (9) and an insulating pad (8).

4. A method for preventing mud cake caking using the biomimetic electroosmotic corrugated structure system of the shield tunnel cutterhead as described in claim 2, characterized in that, include: Step S1: Before the shield cutterhead (3) is operated, the electroosmotic component is energized so that the conductive unit of the crown bag is positively charged and the working face of the shield cutterhead is negatively charged. Step S2: Start the operation of the shield cutterhead (3). During the operation of the shield cutterhead, the electroosmosis component is continuously energized. Step S3: After the operation of the shield cutterhead (3) is completed, the power to the electroosmosis component is cut off.

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