An environmentally friendly tool wear-reducing admixture, a preparation method thereof, and application in hard rock tunneling

Abstract

The invention discloses an environmentally friendly tool wear-reducing admixture, a preparation method thereof, and an application thereof in hard rock excavation, and belongs to the technical field of tunnel construction and tunnel excavation. The invention uses a nonionic surfactant, a lubricant, a foam stabilizer, a dissolving agent, an alkaline regulator, and water as raw materials, the surfactant is used to generate foam, the generated foam can adhere to the cutter head and the surface of the tool during the shield construction process to play a lubricating role, the lubricant is used to further improve the lubricity, the foam stabilizer can increase the half-life of the foam, the dissolving agent can increase the solubility of other components in water, the alkaline regulator can adjust the tool wear-reducing admixture to an alkaline environment, so that the lubricant can play a more efficient lubricating role, the nonionic surfactant can fully foam, and under the action of the foam stabilizer, the foam stability is better maintained, and the tool wear-reducing admixture finally obtained can effectively reduce tool wear and meet environmental protection requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction and tunnel excavation, and in particular relates to an environmentally friendly tool wear-reducing admixture, a preparation method thereof, and application in hard rock excavation. Background Art

[0002] In hard rock tunneling projects, tool wear has always been a key factor restricting project efficiency and cost. After the tool is worn, it is not possible to break rock efficiently, and the tool needs to be replaced in time, which prolongs the construction period of the tunnel. Opening the warehouse to change the tool is also accompanied by risks such as instability of the face and difficulty in controlling surface settlement. Traditional tool materials need to meet a series of indicators such as strength, stiffness, and impact toughness to perform better in normal TBM / shield tunneling. Similarly, because of the need to meet the toughness index, its surface hardness cannot be too high, which will inevitably cause wear when cutting rocks.

[0003] The commonly used methods at present are to improve the tool design, optimize the excavation parameters, use more wear-resistant materials, etc. However, in order to ensure the excavation efficiency and excavation effect, the tool form cannot be adjusted at will during the TBM / shield construction process. Similarly, the excavation parameters also need to be selected according to the formation parameters. Therefore, the current methods are subject to certain limitations.

[0004] With the global awareness of environmental protection, it is particularly important to develop an environmentally friendly tool wear-reducing admixture. In addition, groundwater is likely to be encountered during tunnel construction, and the resulting slag needs to be reused, which requires chemical admixtures to be highly biodegradable to ensure that long-term use will not cause pollution to the soil and groundwater. Therefore, the development of a tool wear-reducing admixture that can effectively reduce tool wear and meet environmental protection requirements has become an urgent problem to be solved in the field of hard rock tunneling technology. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an environmentally friendly tool wear-reducing admixture, a preparation method thereof, and an application thereof in hard rock excavation. The tool wear-reducing admixture provided by the present invention has green and harmless components, can significantly reduce the wear value per unit excavation distance, thereby reducing the tool change frequency of TBM / shield machine and improving excavation efficiency; at the same time, the use of environmentally friendly materials can prevent groundwater pollution while meeting engineering requirements, and reduce the difficulty of shield slag reprocessing.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention provides an environmentally friendly tool wear-reducing additive, which comprises the following components by weight percentage: 3-8% of a nonionic surfactant, 5-10% of a lubricant, 0.3-1% of a foam stabilizer, 0.2-1.2% of a dissolving agent, 0.01-0.05% of an alkaline regulator and the balance of water.

[0008] Preferably, the nonionic surfactant comprises an alkyl glycoside; the average degree of polymerization of the alkyl glycoside is 1.3-1.5.

[0009] Preferably, the lubricant is a mixture of dodecylglycine and polyethylene oxide; the mass ratio of dodecylglycine to polyethylene oxide is 1:(1-2).

[0010] Preferably, the molecular weight of the polyethylene oxide is 2-5 million.

[0011] Preferably, the foam stabilizer is a mixture of methyl cellulose and modified silicone resin polyether emulsion; the mass ratio of the methyl cellulose to the modified silicone resin polyether emulsion is 1:(1-2).

[0012] Preferably, the dissolving agent comprises octyl decyl glucoside.

[0013] Preferably, the alkaline regulator comprises sodium bicarbonate.

[0014] The present invention provides a method for preparing the environmentally friendly tool wear-reducing additive described in the above technical solution, comprising the following steps: dissolving a nonionic surfactant and a foam stabilizer in water, adding a lubricant, a solvent and an alkaline regulator under stirring conditions to obtain the environmentally friendly tool wear-reducing additive.

[0015] Preferably, the stirring rate is 100-150 r·min -1 .

[0016] The present invention also provides the use of the environmentally friendly tool wear-reducing admixture described in the above technical solution in hard rock tunneling.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects:

[0018] (1) The present invention uses non-ionic surfactant, lubricant, foam stabilizer, dissolving agent, alkaline regulator and water as raw materials. The surfactant is used to generate foam. The generated foam can adhere to the cutter head and the surface of the tool during the shield construction process to play a lubricating role. The lubricant is used to further improve the lubricity. The foam stabilizer can increase the half-life of the foam. The dissolving agent can increase the solubility of other components in water. The alkaline regulator can adjust the tool wear-reducing additive to an alkaline environment so that the lubricant can play a lubricating role more efficiently. The non-ionic surfactant can fully foam and better maintain the foam stability under the action of the foam stabilizer. The tool wear-reducing additive finally obtained can effectively reduce tool wear and meet environmental protection requirements.

[0019] (2) The tool wear-reducing admixture of the present invention uses raw materials with strong biodegradability and can be degraded in the natural environment without the risk of polluting groundwater.

[0020] (3) The tool wear-reducing additive of the present invention can reduce tool wear without changing the tool structure and extend the tool life.

[0021] (4) The tool wear-reducing admixture of the present invention can generate foam, which can block the spread of rock powder in hard rock formations and improve the construction environment of the tunnel boring machine. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific implementation methods.

[0024] The embodiment of the present invention provides an environmentally friendly tool wear-reducing additive, which includes the following components by weight percentage: 3-8% non-ionic surfactant, 5-10% lubricant, 0.3-1% foam stabilizer, 0.2-1.2% dissolving agent, 0.01-0.05% alkaline regulator and the balance water.

[0025] In a preferred embodiment, the environmentally friendly tool wear-reducing admixture includes 3-8%, preferably 5-8%, of a nonionic surfactant by mass percentage. The surfactant in the present invention is used to generate foam, and the generated foam can adhere to the cutterhead and the surface of the tool during shield construction, play a lubricating role, and reduce tool wear.

[0026] In a preferred embodiment, the nonionic surfactant includes an alkyl polyglycoside; the average degree of polymerization of the alkyl polyglycoside is 1.3-1.5. The present invention uses an alkyl polyglycoside with an average degree of polymerization within the above range to ensure the solubility and surface activity of the alkyl polyglycoside, and can effectively adhere to the cutterhead and the tool surface during shield construction, thereby improving the lubrication effect of the foam.

[0027] In a preferred embodiment, the environmentally friendly tool wear-reducing additive includes 5-10% lubricant, preferably 5-9% by mass.

[0028] In a preferred embodiment, the lubricant is a mixture of dodecyl glycine and polyethylene oxide; the mass ratio of the dodecyl glycine to polyethylene oxide is 1:(1-2), and is preferably 1:1, 1:1.5 or 1:2. The present invention uses a mixture of dodecyl glycine and polyethylene oxide as a lubricant, which has the advantages of strong environmental degradability, low price, and can be used in large quantities in shield / TBM projects.

[0029] In a preferred embodiment, the molecular weight of the polyethylene oxide is 2-5 million. The present invention uses polyethylene oxide with a molecular weight in the above range as a lubricant. Polyethylene oxide with a high molecular weight can improve lubricity, while a too high molecular weight can reduce its solubility.

[0030] In a preferred embodiment, the environmentally friendly tool wear-reducing additive includes 0.3-1% of a foam stabilizer, preferably 0.3-0.6% by mass.

[0031] In a preferred embodiment, the foam stabilizer is a mixture of methyl cellulose and modified silicone resin polyether emulsion; the mass ratio of the methyl cellulose and modified silicone resin polyether emulsion is 1:(1-2), and is preferably 1:1, 1:1.1, 1:1.2 or 1:2. The present invention uses a mixture of methyl cellulose and modified silicone resin polyether emulsion as a foam stabilizer, both of which are food-grade additives, have the advantage of being environmentally friendly, and can significantly increase the half-life of the foam, ensure the effect of the foam during pipeline transportation, and improve the application effect of the tool wear-reducing admixture.

[0032] In a preferred embodiment, the environmentally friendly tool wear-reducing additive includes 0.2-1.2% of a dissolving agent, preferably 0.3-1.2% by mass. The dissolving agent in the present invention can improve the solubility of other components in water, thereby improving the lubrication effect of the tool wear-reducing additive and reducing tool wear.

[0033] In a preferred embodiment, the dissolving agent comprises octyl decyl glucoside.

[0034] In a preferred embodiment, the environmentally friendly tool wear-reducing additive includes 0.01-0.05% alkaline regulator by mass percentage. The alkaline regulator in the present invention is used to adjust the pH value of the tool wear-reducing additive to 7.5-9.0, and the lubricant molecules can play a more efficient lubricating role in an alkaline environment, and the nonionic surfactant can also fully foam and better maintain the foam stability under the action of the foam stabilizer.

[0035] In a preferred embodiment, the alkaline regulator comprises sodium bicarbonate.

[0036] In a preferred embodiment, the environmentally friendly tool wear-reducing admixture further includes a balance of water, measured by mass percentage; the water is industrial water or tap water used at the construction site.

[0037] The present invention provides a method for preparing the environmentally friendly tool wear-reducing additive described in the above technical solution, comprising the following steps: dissolving a nonionic surfactant and a foam stabilizer in water, adding a lubricant, a dissolving agent and an alkaline regulator under stirring conditions, and obtaining the environmentally friendly tool wear-reducing additive. The tool wear-reducing additive prepared by the preparation method provided by the present invention has good wear-reducing effect and foaming effect.

[0038] In a preferred embodiment, the stirring rate is 100-150 r·min -1 The present invention controls the stirring rate in order to limit the effect of the nonionic surfactant in the tool wear-reducing admixture. Too fast a stirring rate will generate a large number of bubbles, thereby reducing the performance of the tool wear-reducing admixture.

[0039] The present invention also provides the use of the environmentally friendly tool wear-reducing admixture described in the above technical solution in hard rock tunneling.

[0040] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0041] Examples 1-8

[0042] A method for preparing an environmentally friendly tool wear-reducing admixture:

[0043] At room temperature, alkyl polyglycoside, methyl cellulose and modified silicone resin polyether emulsion were added into water and stirred at 120 r·min. -1 The mixture was stirred at a rate of , then dodecyl glycine, polyethylene oxide, octyl decyl glucoside and sodium bicarbonate were added and stirred continuously to obtain an environmentally friendly tool wear-reducing admixture;

[0044] The ingredients of Examples 1-8 are shown in Table 1. The total amount of the environmentally friendly tool wear-reducing additive is 100 g; the average degree of polymerization of the alkyl glycoside is 1.35, and the molecular weight of polyethylene oxide is 3.2 million.

[0045] The ingredients of Comparative Example 1-2 are shown in Table 1.

[0046] Table 1 Composition of Examples 1-8 and Comparative Examples 1-2

[0047]

[0048] Performance Test:

[0049] 1. Foaming experiment

[0050] The foam was prepared by compressed air foaming method, the foaming pressure was controlled to be 300 kPa, the solution concentration was 3%, and the solution was pumped into a foaming gun by an air compressor for foaming. The volume of the prepared solution and the volume of the solution after foaming were tested respectively. The foaming ratio was obtained by dividing the volume of the solution after foaming by the volume of the prepared solution. At the same time, the foaming half-life of the environmentally friendly tool wear-reducing admixture in Examples 1-8 was measured. The results are shown in Table 2.

[0051] 2. Wear test

[0052] A scaled tool test platform was used to cut rock, and the tool wear was tested by the change in tool mass before and after the experiment. Examples 1-8 injected foamed foam into the rock surface and then cut, while Comparative Example 1 only sprayed water on the rock surface, and Comparative Example 2 did not spray. The cutting tools and rocks in each group were made of the same material. After the experiment, the wear rate and wear reduction rate were calculated. The results are shown in Table 2.

[0053] Among them, the calculation formulas for wear rate and wear reduction rate are:

[0054]

[0055] Where a is the wear rate, m is 1 is the original mass of the tool, m 2 is the mass of the tool after wear; b is the wear reduction rate, M i is the tool wear mass of Example i, M 0 This is the tool wear mass of Comparative Example 2.

[0056] Table 2 Experimental results of Examples 1-8 and Comparative Examples 1-2

[0057]

[0058] It can be seen from Table 2 that the half-life of the tool wear-reducing additives in Examples 1-8 after foaming is more than 8 minutes, and they can be reasonably used in engineering, with a high foaming ratio, uniform foaming, and good effect. In addition, the wear rate of the example group using the tool wear-reducing additive is significantly lower than that of the comparative example group without adding the wear-reducing additive, and the wear-reducing effect is improved with the increase of the amount of lubricant, but the difference between Examples 4 and 5 is not large, so a reasonable proportion should be selected for material preparation.

[0059] Comparative Examples 3-7

[0060] The preparation method of the environmentally friendly tool wear-reducing admixture is the same as that in the embodiment. The composition is shown in Table 3. The total amount of the environmentally friendly tool wear-reducing admixture is 100 g; the average polymerization degree of the alkyl glycoside is 1.35, and the molecular weight of the polyethylene oxide is 3.2 million.

[0061] Table 3 Composition of Comparative Examples 3-7

[0062]

[0063] The performance of Comparative Examples 3-7 was tested according to the above foaming test and wear test. The results are shown in Table 4.

[0064] Table 4 Experimental results of comparative examples 3-7

[0065]

[0066] As can be seen from Table 4, Comparative Example 3 increases the dosage of nonionic surfactant, and the wear rate is improved compared with Example 5. This is because the foaming ratio is increased, and the lubricating component is reduced under the same injection amount conditions; Comparative Examples 4 and 5 only use one lubricant, and the wear rate is increased, indicating that the two lubricants will promote each other and should be used in combination; Comparative Example 6 reduces the dosage of alkaline regulator, and the wear rate is increased, indicating that the lubricant should be in a suitable acid-base environment to play a better role; Comparative Example 7 increases the dosage of foam stabilizer, and the wear rate is slightly increased, indicating that the foam can play a good role under stable conditions, and increasing the dosage of foam stabilizer has little effect on the wear reduction effect, and the foam stabilizer should be appropriately added.

[0067] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An environmentally friendly tool wear-reducing admixture, characterized in that: The composition comprises the following components by weight percentage: 3-8% of nonionic surfactant, 5-10% of lubricant, 0.3-1% of foam stabilizer, 0.2-1.2% of dissolving agent, 0.01-0.05% of alkaline regulator and the balance of water; The nonionic surfactant is an alkyl polyglycoside; the lubricant is a mixture of dodecyl glycine and polyethylene oxide; the mass ratio of dodecyl glycine to polyethylene oxide is 1:(1-2); the foam stabilizer is a mixture of methyl cellulose and modified silicone resin polyether emulsion; the mass ratio of methyl cellulose to modified silicone resin polyether emulsion is 1:(1-2); the dissolving agent is octyl decyl glucoside.

2. The environmentally friendly tool wear-reducing admixture according to claim 1, characterized in that: The average degree of polymerization of the alkyl glycoside is 1.3-1.

5.

3. The environmentally friendly tool wear-reducing admixture according to claim 1, characterized in that: The molecular weight of the polyethylene oxide is 2-5 million.

4. The environmentally friendly tool wear-reducing admixture according to claim 1, characterized in that: The alkaline regulator includes sodium bicarbonate.

5. The method for preparing the environmentally friendly tool wear-reducing admixture according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: dissolving a nonionic surfactant and a foam stabilizer in water, adding a lubricant, a solvent and an alkaline regulator under stirring conditions, and obtaining the environmentally friendly tool wear-reducing additive.

6. The preparation method according to claim 5, characterized in that: The stirring rate is 100-150 r·min -1 .

7. Use of the environmentally friendly tool wear-reducing admixture according to any one of claims 1 to 4 in hard rock tunneling.

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