A frozen eliminating method for treating the mud cake of a shield cutter

Abstract

The application discloses a frozen eliminating method for treating mud cake of a shield cutter, which comprises the following steps: driving a liquid nitrogen vehicle to a shutdown position of a shield machine, sealingly connecting a liquid nitrogen conveying pipe on the liquid nitrogen vehicle with a reserved grouting hole through a grouting pipe, and / or sealingly connecting the liquid nitrogen conveying pipe on the liquid nitrogen vehicle with an advanced grouting hole through the grouting pipe; spraying liquid nitrogen on the mud cake on the shield machine through the reserved grouting hole and / or the advanced grouting hole to freeze the mud cake; starting the shield machine, and making the mud cake break by the high-power torque of the shield machine; and after the elimination is completed, the shield machine returns to normal. The method has the advantages that the liquid nitrogen can quickly freeze the mud cake and form an ice film between the mud cake and the cutter and between the mud cake and the cutter, the efficiency of solving the problem is improved, and the construction period is shortened.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel construction technology, and in particular to a method for removing frozen mud cake from the cutterhead of a shield tunnel. Background Technology

[0002] With the rapid development of urban construction, the application of shield tunneling is becoming increasingly widespread, often involving various complex geological formations, and the phenomenon of mud cake formation on the shield cutterhead is common. Once mud cake forms on the shield cutterhead, the cutter becomes integrated with the soil, making it difficult to perform cutting. This not only affects the shield's advancement speed, but in severe cases, it can even cause the shield machine to jam, preventing further advancement and delaying the construction schedule.

[0003] Cutterhead mud cake formation is primarily caused by the easy hydration of sticky substances in the strata, leading to easy adhesion between the excavated soil and cutterhead. Once adhered to the cutterhead and cutterhead, this increases the tunnel boring machine's torque, causing rapid temperature rise at the cutterhead center. High temperatures reduce cutter penetration and decrease tunneling speed, severely impacting construction efficiency and progress. However, mild cutterhead mud cake formation can be improved through various methods, such as modifying the cutterhead and cutterhead arrangement, adjusting the soil chamber size, the length of the auger entering the soil chamber, soil improvement, slurry ratio adjustments, and adjusting propulsion parameters. For strata particularly prone to mud cake formation, a well-designed central flushing system can be implemented to delay its onset. However, these methods only temporarily alleviate the problem, have a high recurrence rate, and are costly and time-consuming, without effectively removing the mud cake. Summary of the Invention

[0004] The purpose of this invention is to provide a method for eliminating the freezing of mud cake on the cutterhead of a tunnel boring machine. This method uses pre-reserved grouting holes and / or advanced grouting holes in the tunnel boring machine to rapidly freeze the mud cake with liquid nitrogen and form an ice film between the mud cake and the cutterhead and between the mud cake and the cutter, thereby improving the efficiency of problem-solving and shortening the construction period.

[0005] The technical solution of this invention is implemented as follows:

[0006] A method for removing frozen mud cake from tunnel cutterheads includes the following steps:

[0007] S1: Based on the changes in the tunnel boring machine's construction parameters, determine whether the tunnel boring machine is forming mud cakes. If mud cakes form on the tunnel boring machine, stop the machine.

[0008] S2: Stop grouting, pull the grouting pipe out of the grouting pipeline, and seal the grouting hole;

[0009] S3: Unblock and clean the reserved grouting holes and grouting pipes on the shield cutterhead;

[0010] And / or, dredge and clean the advanced grouting holes and grouting pipes on the shield shell;

[0011] S4: Drive the liquid nitrogen truck into the shield machine's stopping position and seal the liquid nitrogen delivery pipe on the liquid nitrogen truck to the reserved grouting hole through the grouting pipe;

[0012] And / or, seal the liquid nitrogen delivery pipe on the liquid nitrogen vehicle to the pre-grouting hole via a grouting pipe;

[0013] S5: Freeze the mud cake on the tunnel boring machine by injecting liquid nitrogen through reserved grouting holes and / or advanced grouting holes;

[0014] S6: The tunnel boring machine starts up and uses its high-power torque to break up the mud cake. After the mud cake is removed, the tunnel boring machine returns to normal.

[0015] Furthermore, in step S5, liquid nitrogen is sprayed onto the tunnel boring machine mud cake to freeze it. After freezing, an ice film will form between the mud cake and the cutter head, and between the mud cake and the cutter head.

[0016] The beneficial effects of this invention are:

[0017] 1. Compared with traditional manual physical removal methods, this invention makes full use of the mechanical properties of the contact surface. By freezing, the structure of the contact surface is changed into a composite structure composed of three materials: frozen mud cake, ice film, and cutter disc, and frozen mud cake, ice film, and cutter. The damage is limited to the weak ice film, which reduces its cutting strength and allows the mud cake to fall off. No direct manual contact is required, which reduces the construction difficulty and workload. Under the premise of ensuring low temperature, it is not easy to repeatedly stick together.

[0018] 2. Liquid nitrogen can be transported and connected using small industrial liquid nitrogen trucks. Compared with conventional brine freezing, there is no need to build a complete brine freezing equipment system, which occupies less space, and the transportation method is safer and more convenient. Moreover, the freezing efficiency is high, which can more efficiently and quickly clean the mud cake in front of the tunnel boring machine cutterhead.

[0019] 3. This invention utilizes existing pre-reserved grouting holes and / or advanced grouting holes, eliminating the need for additional drilling and drilling, thus providing flexibility, reducing the construction process of disassembling the shield cutterhead, lowering project costs, and saving construction time.

[0020] 4. Compared with traditional methods for improving cutterhead mud cake, the freezing method for eliminating shield tunneling machine mud cake does not require the addition of other chemical materials or special processes, and will not cause pollution to the surrounding environment. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of freezing mud cake with liquid nitrogen through pre-reserved grouting holes in the cutter head or freezing mud structure with liquid nitrogen through advanced grouting holes.

[0023] Figure 2 This is a schematic diagram of the shield tunnel cutterhead. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] According to an embodiment of the present invention, a method for removing frozen mud cake from the cutterhead of a tunnel boring machine is provided.

[0026] Example 1:

[0027] Reference Figure 1-2 According to the embodiment of the present invention, the method for freezing and eliminating mud cake on the shield cutterhead involves the following steps: When mud cake forms on the shield machine, the shield machine is stopped; grouting is stopped, the grouting pipe is withdrawn from the grouting pipe 8, and the grouting hole is sealed; the reserved grouting hole 3 on the shield cutterhead 1 is cleared and cleaned from the grouting pipe 8; the liquid nitrogen delivery pipe 6 on the liquid nitrogen truck 7 is sealed and connected to the reserved grouting hole 3 through the grouting pipe 8, and liquid nitrogen is sprayed onto the mud cake 4 to freeze it. The liquid nitrogen causes the temperature of the mud cake 4 to rapidly drop below zero degrees Celsius, causing an ice film to quickly form between the mud cake 4 and the cutter 2, and between the mud cake 4 and the surface of the cutterhead 1. Since the ice film has a certain degree of brittleness and low strength, when the shield machine is started after freezing, the high-power torque of the shield machine causes the ice film between the mud cake 4 and the cutter 2, and between the mud cake 4 and the cutterhead 1 to break, and the mud cake falls off and is eliminated. After the mud cake is completely eliminated, the shield machine resumes normal cutting function.

[0028] The reserved grouting hole 3 on the cutterhead 1 was originally used for grouting and improving the soil in front of the shield tunnel. During the shield tunneling process, in order to improve the soil in front of the cutterhead 1 when necessary, the reserved grouting hole 3 will be opened on the cutterhead 1. In this embodiment, it is used to transport liquid nitrogen to the front of the cutterhead 1 and serve as a channel for spraying liquid nitrogen into the mud cake 4.

[0029] In addition, the reserved grouting holes 3 on the shield cutterhead 1 freeze the inside of the shield excavation chamber and the front of the shield cutterhead 1. When the shield machine is started, the cutterhead 1 rotates through the torque generated by the bearing, and the cutter 2 also starts to rotate, which plays the role of cutting the soil.

[0030] Example 2

[0031] Reference Figure 1-2 When mud cake forms on the tunnel boring machine (TBM), the TBM is stopped; grouting is stopped, the grouting pipe is pulled out from the grouting pipe 8, and the grouting hole is sealed; the advanced grouting hole 9 on the cutterhead 1 is cleared and cleaned from the grouting pipe 8; the liquid nitrogen delivery pipe 6 on the liquid nitrogen truck 7 is sealed and connected to the advanced grouting hole 9 through the grouting pipe 8, and liquid nitrogen is sprayed onto the mud cake 4 to freeze it. The liquid nitrogen causes the temperature of the mud cake 4 to quickly drop below zero, forming an ice film between the mud cake 4 and the cutter 2, and between the mud cake 4 and the cutterhead 1. Because the ice film is brittle and has low strength, when the TBM is started after freezing, its high-power torque causes the ice film between the mud cake 4 and the cutter 2, and between the mud cake 4 and the cutterhead 1 to break, and the mud cake 4 falls off and is eliminated. After the mud cake 4 is completely eliminated, the TBM resumes normal cutting function.

[0032] The advanced grouting hole 9, originally a horizontal grouting hole near the shield shell of the tunnel boring machine (TBM) for injecting grout into the front of the TBM to reinforce the soil layer, is used in this embodiment to transport liquid nitrogen to the front of the cutterhead 1, serving as a channel for spraying liquid nitrogen into the mud cake 4. The advanced grouting hole 9 on the shield shell freezes the vertical surface by transporting liquid nitrogen, thus eliminating the mud cake from the TBM.

[0033] Example 3

[0034] Reference Figure 1-2 When mud cake forms on the tunnel boring machine (TBM), the TBM is stopped; grouting is stopped, the grouting pipe is pulled out from the grouting pipe 8, and the grouting holes are sealed; the reserved grouting holes 9 on the cutterhead 1 and the grouting pipe 8 are cleared and cleaned, and the advanced grouting holes 9 on the shield shell and the grouting pipe 8 are also cleared and cleaned; then the liquid nitrogen truck 7 is driven into the TBM's stop position, and the liquid nitrogen delivery pipe 6 on the liquid nitrogen truck 7 is sealed and connected to the reserved grouting holes 3 and the advanced grouting holes 9 through the grouting pipe 8; liquid nitrogen is sprayed onto the mud cake 4 on the TBM through the reserved grouting holes 3 and the advanced grouting holes 9 to freeze it; the TBM is started, and its high-power torque breaks up the mud cake. After the mud cake is cleared, the TBM returns to normal.

[0035] The vertical surface of the mud cake 4, the interior of the shield excavation chamber, and the front of the shield cutterhead 1 are frozen by using the advanced grouting hole 9 and the reserved grouting hole 3. The combination of the two methods can quickly freeze the mud cake 4 and form an ice film between the mud cake 4 and the cutterhead 1 and between the mud cake 4 and the cutter 2. The frozen mud cake 4-ice film 5-cutterhead 1 and mud cake 4-ice film 5-cutter 2 form a composite structure composed of three materials, which further improves the efficiency of removing the mud cake 4.

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for removing frozen mud cake from shield tunnel cutterheads, characterized in that, Includes the following steps: S1: Based on the changes in the tunnel boring machine's construction parameters, determine whether the tunnel boring machine is forming mud cakes. If mud cakes form on the tunnel boring machine, stop the machine. S2: Stop grouting, pull the grouting pipe out of the grouting pipeline, and seal the grouting hole; S3: Unblock and clean the reserved grouting holes and grouting pipes on the shield cutterhead; And / or, dredge and clean the advanced grouting holes and grouting pipes on the shield shell; S4: Drive the liquid nitrogen truck into the shield machine's stopping position and seal the liquid nitrogen delivery pipe on the liquid nitrogen truck to the reserved grouting hole through the grouting pipe; And / or, seal the liquid nitrogen delivery pipe on the liquid nitrogen vehicle to the pre-grouting hole via the grouting pipe; S5: Liquid nitrogen is injected into the mud cake on the tunnel boring machine through the reserved grouting holes and / or the advanced grouting holes to freeze it. After freezing, an ice film will form between the mud cake and the cutter head, and between the mud cake and the cutter head. S6: The tunnel boring machine starts up and uses its high-power torque to break up the mud cake. After the mud cake is removed, the tunnel boring machine returns to normal.

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