Shield lubricant capable of realizing rapid muck separation and preparation method thereof

Abstract

The invention belongs to the technical field of shield construction, and particularly discloses a shield lubricant capable of realizing rapid muck separation and a preparation method of the shield lubricant. The shield lubricant capable of realizing rapid separation of the muck comprises 25%-55% of alkyl alcohol phosphate salt, 10%-25% of polyethylene glycol, 15%-25% of fatty alcohol polyoxyethylene polyoxypropylene ether and 5%-20% of water-soluble polyether organic silicon. The shield lubricant capable of quickly separating the muck can play roles in lubricating, improving the muck and defoaming cloud points, so that the muck separation efficiency is higher, a mud cake is tighter, and the water content of the mud cake is 1t; 30%. The shield lubricant capable of realizing rapid muck separation is suitable for urban center shield project construction and mud and sand field separation, and has the advantages of high efficiency, low cost, capability of shortening the construction period and the like.

Description

Technical Field

[0001] This invention belongs to the field of tunnel boring machine (TBM) construction technology, and specifically discloses a TBM lubricant that enables rapid separation of excavated soil and its preparation method. Background Technology

[0002] In urban subway construction projects, the excavated soil from tunnel boring machines (TBMs) is typically transported by a third party to a nearby professional mud separation and treatment plant. However, many urban project sites lack this capability. Furthermore, due to limited space, there is insufficient room to install numerous pieces of equipment or store mud cakes and gravel (such as the Xiaolongkan project site on Chongqing Metro Line 27, located in the old city center surrounded by dense residential areas). Therefore, the excavated soil must be separated on-site before being efficiently, quickly, and environmentally friendly transported out of the city to avoid impacting the progress of the preceding TBM tunneling and delaying the project schedule.

[0003] The current method for separating excavated soil on-site involves using shield tunneling foaming agents to separate the excavated soil into sand and mud. The mud is then pressed into cakes, and the sand and gravel are stacked for defoaming before being transported together with the mud cakes. Shield tunneling foaming agents lubricate the cutterhead and improve the excavated soil, thus enabling subsequent mud separation and mud cake filtration. However, the foaming agents generate a lot of foam during the soil separation and mud cake filtration process, which still clogs the filter screens even when defoaming with silicone defoamers. Frequent filter replacement not only delays the project but also results in poorly compacted mud cakes. Furthermore, the sand and gravel contain undissolved fine bubbles, causing water leakage and environmental pollution during transport out of the city. To improve the efficiency of the subsequent separation and cake pressing process, the amount of shield tunneling foaming agent used must be reduced, but this reduces the lubrication effect on the cutterhead and the soil improvement effect. While this allows for a smooth connection between the preceding and following processes, the overall efficiency is significantly reduced. Summary of the Invention

[0004] The purpose of this invention is to provide a shield tunneling lubricant that enables rapid separation of excavated soil and its preparation method, in order to solve the technical problem that existing shield tunneling foam agents cannot simultaneously achieve the effects of lubrication, excavated soil improvement, and environmentally friendly transportation of filter cake.

[0005] A first aspect of the present invention provides a shield tunneling lubricant capable of rapid separation of excavated soil and debris, comprising: Alkyl alcohol phosphate salts: 25%-55%; Polyethylene glycol: 10%-25%; Fatty alcohol polyoxyethylene polyoxypropylene ether: 15%-25%; Water-soluble polyether silicone: 5%-20%.

[0006] Preferably, when the shield tunneling strata are hard rock strata, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 45℃-50℃.

[0007] Preferably, when the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 45℃-50℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 2.5-3:1.

[0008] Preferably, when the shield tunneling strata are sandstone strata, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 40℃-45℃.

[0009] Preferably, when the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 40℃-45℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 2-2.5:1.

[0010] Preferably, when the tunnel stratum is a sand and gravel stratum, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 28℃-35℃.

[0011] Preferably, when the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 28℃-35℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 1.5-1.8:1.

[0012] Preferably, when the tunnel stratum is soft soil, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 25℃-30℃.

[0013] Preferably, when the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 25℃-30℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 1.3-1.7:1.

[0014] A second aspect of the present invention provides a method for preparing the above-mentioned shield tunneling lubricant capable of rapid separation of excavated soil and debris, comprising: Step 1: Determine the shield tunneling stratum type and determine the design turbidity point of fatty alcohol polyoxyethylene polyoxypropylene ether based on the shield tunneling stratum type; Step 2: Determine the ratio of EO to PO in fatty alcohol polyoxyethylene polyoxypropylene ether based on the designed cloud point; Step 3: Mix 25%-55% of alkyl alcohol phosphate salt, 10%-25% of polyethylene glycol, 5%-20% of water-soluble polyether silicone and 15%-25% of the fatty alcohol polyoxyethylene polyoxypropylene ether obtained in Step 2 evenly to obtain a shield lubricant that can achieve rapid separation of slag and soil.

[0015] The shield tunneling lubricant and its preparation method for achieving rapid separation of excavated soil of the present invention have the following advantages compared with the prior art: The alkyl alcohol phosphate salt, polyethylene glycol, fatty alcohol polyoxyethylene polyoxypropylene ether, and water-soluble polyether organosilicon of the present invention work synergistically to lubricate, improve slag, and defoam at the cloud point. It can quickly separate slag and press it into cakes, achieving a seamless connection between slag separation and cake pressing. Moreover, due to the absence of foam, the slag separation efficiency is higher, the mud cake is more compact, and the moisture content of the mud cake is <30%, which enables environmentally friendly transportation.

[0016] The shield lubricant of this invention, which enables rapid separation of excavated soil and slag, is suitable for shield tunneling projects in urban centers and for on-site separation of mud and sand. It has the advantages of high efficiency, low cost, and shortened construction period. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a method for preparing a shield tunneling lubricant that enables rapid separation of excavated soil, according to an embodiment of the present invention. Detailed Implementation

[0018] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0019] A first aspect of the present invention provides a shield tunneling lubricant that enables rapid separation of excavated soil and debris, comprising: 25%-55% alkyl alcohol phosphate salt; 10%-25% polyethylene glycol; 15%-25% fatty alcohol polyoxyethylene polyoxypropylene ether and 5%-20% water-soluble polyether organosilicon.

[0020] For example, the amount of alkyl alcohol phosphate salt used is 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc.; the amount of polyethylene glycol used is 10%, 15%, 20%, 25%, etc.; the amount of fatty alcohol polyoxyethylene polyoxypropylene ether used is 15%, 18%, 20%, 23%, 25%, etc.; and the amount of water-soluble polyether silicone used is 5%, 10%, 15%, 20%, etc.

[0021] The aforementioned alkyl alcohol phosphates exhibit high reactivity. Under extreme pressure conditions of high pressure and high friction between the cutterhead and the soil / rock, alkyl alcohol phosphates can form a dense and robust phosphorus-iron reactive film, isolating the cutterhead cutting tools from the soil / rock particles. This significantly reduces cutterhead torque and protects the cutterhead, especially in highly abrasive formations such as hard rock, sandstone, and gravel, effectively extending tool life and reducing tool change frequency and downtime. Furthermore, the excellent lubricity of alkyl alcohol phosphates prevents clay particles from adhering to the cutterhead panel and prevents soil from hardening into a cake.

[0022] Furthermore, alkyl alcohol phosphate salts, as anionic surfactants, can reduce the surface tension of oil-water and soil-water, emulsify and disperse the cut-off slag particles, giving the slag better fluidity and plasticity, making it easier to discharge through screw conveyors, effectively preventing gushing and soil blockage, and playing a lubricating and dispersing role.

[0023] The lubricating properties of polyethylene glycol can reduce friction between soil particles, improve its fluidity and workability; the dispersibility of polyethylene glycol helps prevent the agglomeration of particles in the soil, improves the overall uniformity and stability, and can optimize and improve the soil.

[0024] The aforementioned fatty alcohol polyoxyethylene polyoxypropylene ethers act as foam controllers, performance enhancers, and system controllers.

[0025] Fatty alcohol polyoxyethylene polyoxypropylene ether can significantly reduce the surface tension of water, making it easier for the lubricant to penetrate into the tiny cracks in the slag and rock. It can effectively spread and wet at the solid-liquid interface, and can more quickly and evenly coat the cutter head and slag particles and penetrate into the clay, breaking down its stickiness and preventing mud cake formation from the source.

[0026] Furthermore, fatty alcohol polyoxyethylene polyoxypropylene ether itself has lubricating properties, and its polymer chains can form an adsorption film on the surface of metals and particles, further enhancing the friction reduction effect, helping to reduce the torque of the cutter head, and protecting the cutting tools.

[0027] This invention achieves low-temperature solubility and high-temperature precipitation of fatty alcohol polyoxyethylene polyoxypropylene ether by controlling the cloud point of fatty alcohol polyoxyethylene polyoxypropylene ether to match the formation temperature, thereby enhancing lubrication and defoaming.

[0028] For example, when the tunnel boring machine is located in hard rock formation, the design cloud point of fatty alcohol polyoxyethylene polyoxypropylene ether is 45℃-50℃, specifically 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, etc. In this case, the ratio of ethylene oxide to propylene oxide in the fatty alcohol polyoxyethylene polyoxypropylene ether is EO:PO=2.5-3:1. For example, it can be EO:PO=2.5:1, EO:PO=2.6:1, EO:PO=2.7:1, EO:PO=2.8:1, EO:PO=2.9:1, EO:PO=3:1, etc.

[0029] When the tunnel boring machine (TBM) is located in sandstone formation, the design cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 40℃-45℃, specifically 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, etc. In this case, the ratio of ethylene oxide to propylene oxide in the fatty alcohol polyoxyethylene polyoxypropylene ether is EO:PO = 2-2.5:1. Examples include EO:PO = 2:1, EO:PO = 2.1:1, EO:PO = 2.2:1, EO:PO = 2.3:1, EO:PO = 2.4:1, EO:PO = 2.5:1, etc.

[0030] When the tunnel boring machine is located in a sandy or gravelly stratum, the design cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 28℃-35℃, specifically 28℃, 30℃, 32℃, 34℃, 35℃, etc. In this case, the ratio of ethylene oxide to propylene oxide in the fatty alcohol polyoxyethylene polyoxypropylene ether is EO:PO = 1.5-1.8:1. For example, it can be EO:PO = 1.5:1, EO:PO = 1.6:1, EO:PO = 1.7:1, EO:PO = 1.8:1, etc.

[0031] When the tunnel boring machine is located in soft soil, the design cloud point of fatty alcohol polyoxyethylene polyoxypropylene ether is 25℃-30℃, specifically 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, etc. In this case, the ratio of ethylene oxide to propylene oxide in the fatty alcohol polyoxyethylene polyoxypropylene ether is EO:PO = 1.3-1.7:1. For example, it can be EO:PO = 1.3:1, EO:PO = 1.4:1, EO:PO = 1.5:1, EO:PO = 1.6:1, EO:PO = 1.7:1, etc.

[0032] The water-soluble polyether silicone of this invention provides extremely long-lasting lubrication, significantly reducing cutter head torque, and is particularly suitable for highly abrasive formations such as hard rock, sandstone, and gravel. The tough adsorption film of the water-soluble polyether silicone can separate the cutter head, cutting tools, and hard rock fragments, reducing wear and greatly extending tool life; the extremely low surface tension of the water-soluble polyether silicone gives it excellent anti-adhesion properties.

[0033] When in use, there is no need to modify the existing shield tunneling equipment. The shield lubricant of this invention, which enables rapid separation of excavated soil, can be directly used in the shield machine foam agent system to replace the traditional shield foam agent. The concentration on the machine is 1.5%-5%.

[0034] This invention replaces the shield tunneling foaming agent with a shield lubricant that enables rapid separation of excavated material and soil. It cleverly combines water solubility and defoaming properties by utilizing the cloud point of fatty alcohol polyoxyethylene polyoxypropylene ether. The temperature generated during cutterhead cutting against the soil and rock is used as the core temperature for the cloud point design. Below the cloud point, the foaming agent exhibits its properties; above the cloud point, it not only has defoaming properties but also enhanced lubrication. This shield lubricant enables rapid separation of excavated material and soil, lubricating the cutterhead and improving the excavated material during the preceding shield tunneling process while ensuring no foaming occurs in the subsequent process. This achieves rapid and efficient separation of excavated material and soil, compaction of the mud cake, and environmentally friendly and pollution-free transportation of the mud cake and gravel out of the city.

[0035] The alkyl alcohol phosphate salt, polyethylene glycol, fatty alcohol polyoxyethylene polyoxypropylene ether, and water-soluble polyether organosilicon used in the embodiments of this invention work synergistically to lubricate, improve the slag, and defoam at the cloud point, thereby rapidly separating the slag and quickly pressing it into cakes. This achieves a seamless connection between separation and cake pressing, and because it is foam-free, the slag separation efficiency is higher, the cake is more compact, and the moisture content of the cake is <30%, enabling environmentally friendly transportation. This shield tunneling lubricant, which enables rapid slag separation, is suitable for shield tunneling projects in urban centers and for on-site separation of mud and sand, offering advantages such as high efficiency, low cost, and shortened construction period.

[0036] A second aspect of this invention provides a method for preparing the above-mentioned shield tunneling lubricant capable of rapid separation of excavated soil and debris, comprising: Step 1: Determine the shield tunneling stratum type and determine the design turbidity point of fatty alcohol polyoxyethylene polyoxypropylene ether based on the shield tunneling stratum type.

[0037] For example, if the strata type of the tunnel is hard rock, sandstone, gravel, or soft soil, then the design turbidity point of fatty alcohol polyoxyethylene polyoxypropylene ether for hard rock is 45℃-50℃; for sandstone, it is 40℃-45℃; for gravel, it is 28℃-35℃; and for soft soil, it is 25℃-30℃.

[0038] Step 2: Determine the ratio of EO to PO in fatty alcohol polyoxyethylene polyoxypropylene ether based on the designed cloud point.

[0039] For example, when the design cloud point is 45℃-50℃, EO:PO = 2.5-3:1; when the design cloud point is 40℃-45℃, EO:PO = 2-2.5:1; when the design cloud point is 28℃-35℃, EO:PO = 1.5-1.8:1; and when the design cloud point is 25℃-30℃, EO:PO = 1.3-1.7:1.

[0040] Step 3: Mix 25%-55% of alkyl alcohol phosphate salt, 10%-25% of polyethylene glycol, 5%-20% of water-soluble polyether silicone and 15%-25% of the fatty alcohol polyoxyethylene polyoxypropylene ether obtained in Step 2 evenly to obtain a shield lubricant that can achieve rapid separation of slag and soil.

[0041] This invention provides a shield tunneling lubricant that enables rapid separation of excavated material and soil, solving the challenges faced by the shield tunneling industry in urban centers with limited space, seamless integration of upstream and downstream processes, difficulty in separating excavated material and soil in confined areas, and difficulty in quickly and pollution-free transport of mud cakes and gravel out of the city. This shield tunneling lubricant requires no modification to existing equipment and does not affect shield tunneling efficiency.

[0042] The shield tunneling lubricant of this invention, which enables rapid separation of excavated material and soil, saves on silicone defoamers, achieving foam-free slag discharge from the conveyor belt, slag and soil separation, and filter press operation without defoamers. Taking the Xiaolongkan project of Chongqing Metro Line 27 as an example, if existing shield tunneling foaming agents were used, 1.08 million yuan worth of silicone defoamers would be consumed, while this invention eliminates the need for silicone defoamers. Furthermore, the shield tunneling lubricant of this invention, which enables rapid separation of excavated material and soil, saves 40% of the excavated material handling space compared to using shield tunneling foaming agents.

[0043] The shield lubricant of this invention, which enables rapid separation of excavated material and soil, can replace shield foaming agents, resulting in better shield parameters, reduced total thrust and torque, and the ability to appropriately increase the propulsion speed. Verification has shown that this shield lubricant can shorten the construction period by 2-3 months. Because it is foam-free, subsequent excavated material separation efficiency is higher, the mud cake is more compact, and the moisture content is <30%, allowing for timely and environmentally friendly, drip-free transport of the mud cake and gravel.

[0044] This invention provides a shield tunneling lubricant that enables rapid separation of excavated material and soil, facilitating smooth coordination between upstream and downstream processes and resolving the conflict between shield tunneling construction and on-site excavated material handling in urban centers. Due to its foam-free, ultra-lubricating properties, it reduces the failure rate, lowers the frequency of cutter replacements, and also reduces the frequency of filter screen replacements during slurry filtration, ensuring project completion. Verification has shown that using this shield tunneling lubricant for rapid excavated material and soil separation can save up to 5% in direct costs.

[0045] The above descriptions are merely a few embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A shield tunneling lubricant capable of rapid separation of excavated soil and debris, characterized in that, include: Alkyl alcohol phosphate salts: 25%-55%; Polyethylene glycol: 10%-25%; Fatty alcohol polyoxyethylene polyoxypropylene ether: 15%-25%; Water-soluble polyether silicone: 5%-20%.

2. The shield tunneling lubricant for rapid separation of excavated soil as described in claim 1, characterized in that, When the tunnel strata are hard rock strata, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 45℃-50℃.

3. The shield tunneling lubricant for rapid separation of excavated soil as described in claim 2, characterized in that, When the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 45℃-50℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 2.5-3:

1.

4. The shield tunneling lubricant for rapid separation of excavated soil as described in claim 1, characterized in that, When the tunnel strata are sandstone, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 40℃-45℃.

5. The shield tunneling lubricant for rapid separation of excavated soil according to claim 4, characterized in that, When the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 40℃-45℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 2-2.5:

1.

6. The shield tunneling lubricant for rapid separation of excavated soil according to claim 1, characterized in that, When the tunnel boring machine is located in a sandy and gravelly stratum, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 28℃-35℃.

7. The shield tunneling lubricant for rapid separation of excavated soil according to claim 6, characterized in that, When the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 28℃-35℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 1.5-1.8:

1.

8. The shield tunneling lubricant for rapid separation of excavated soil according to claim 1, characterized in that, When the tunnel stratum is soft soil, the design turbidity point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 25℃-30℃.

9. The shield tunneling lubricant for rapid separation of excavated soil according to claim 8, characterized in that, When the designed cloud point of the fatty alcohol polyoxyethylene polyoxypropylene ether is 25℃-30℃, the EO:PO ratio in the fatty alcohol polyoxyethylene polyoxypropylene ether is 1.3-1.7:

1.

10. A method for preparing a shield tunneling lubricant capable of rapid separation of excavated soil as described in any one of claims 1-9, characterized in that, include: Step 1: Determine the shield tunneling stratum type and determine the design turbidity point of fatty alcohol polyoxyethylene polyoxypropylene ether based on the shield tunneling stratum type; Step 2: Determine the ratio of EO to PO in fatty alcohol polyoxyethylene polyoxypropylene ether based on the designed cloud point; Step 3: Mix 25%-55% of alkyl alcohol phosphate salt, 10%-25% of polyethylene glycol, 5%-20% of water-soluble polyether silicone and 15%-25% of the fatty alcohol polyoxyethylene polyoxypropylene ether obtained in Step 2 evenly to obtain a shield lubricant that can achieve rapid separation of slag and soil.

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