Quick-setting anti-corrosion sprayed concrete in subsea tunnel environment as well as preparation method and application of quick-setting anti-corrosion sprayed concrete

Abstract

The invention belongs to the technical field of sprayed concrete, and particularly relates to rapid-hardening anti-corrosion sprayed concrete in a subsea tunnel environment as well as a preparation method and application of the rapid-hardening anti-corrosion sprayed concrete. The concrete is prepared from the following raw materials in parts by weight: 480-530 parts of ordinary Portland cement, 850-900 parts of fine aggregate, 740-800 parts of coarse aggregate, 160-190 parts of water, 5-10 parts of a water reducing agent, 40-45 parts of an accelerator, 10-16 parts of a powder material and 15-20 parts of a corrosion inhibitor. The sprayed concrete limits generation and development of microcracks in the earliest stage of concrete forming, permeation of corrosive seawater is avoided, and the anti-corrosion sprayed concrete can play a role in resisting corrosion of seawater in the later stage through an internal hydrophobic material. The early strength of the sprayed concrete is guaranteed and the resilience is reduced by adding the early strength powder material, the corrosion resistance of the sprayed concrete is enhanced by adding the corrosion inhibitor, and the sprayed concrete has a relatively good effect in the aspect of resisting concrete corrosion.

Description

Technical Field

[0001] The invention belongs to the technical field of shotcrete, and particularly relates to a quick-setting and anti-corrosion shotcrete under the seabed tunnel environment, a preparation method thereof and an application thereof. Background Art

[0002] A seabed tunnel is a tunnel built under the seabed or underwater, with complex tunnel geological conditions, different surrounding rock grades, and many fracture openings, and is affected by high-pressure erosive seawater during the excavation process. When shotcreting is carried out on the rock mass surface during the excavation of a seabed tunnel, when conventional shotcrete is used, under the action of high-pressure erosive seawater, the adhesion of the shotcrete is poor, water leakage will occur 1 day after construction, and white substances (mainly calcium carbonate) will precipitate out after 7 days, seriously affecting the appearance beauty of the primary support structure and the construction quality of the tunnel.

[0003] In the prior art, a composite admixture for tunnel shotcrete is disclosed. The composite admixture is incorporated into the shotcrete through the proportioning of various substances, and by solidifying the free calcium ions in the cement hydration products, the precipitation of calcium carbonate crystals is reduced. This admixture shows good anti-corrosion effect in mountain tunnels. This solution is only "single anti-corrosion" and does not consider the complexity of the construction environment of seabed tunnels, and cannot meet the requirements for the performance of concrete in the presence of a large amount of erosive seawater. In the application process of the prior art in seabed tunnels, there are widespread problems of high rebound and high corrosion. Among them, high rebound is usually solved by accelerating the setting time and enhancing the viscosity of the concrete, and anti-corrosion is usually treated by increasing the initial density and adding functional materials. At present, there is no technology that can consider solving these two major problems at the same time. Summary of the Invention

[0004] The purpose of the invention is to provide a quick-setting and anti-corrosion shotcrete under the seabed tunnel environment, a preparation method thereof and an application thereof, so as to overcome the deficiencies of the prior art, be able to adapt to the construction method and environment of seabed tunnels, and while ensuring its quick setting and relatively high early strength, it also has excellent anti-corrosion performance.

[0005] In order to achieve the above purpose, the technical solution of the invention is as follows:

[0006] In the first aspect, the invention provides a quick-setting and anti-corrosion shotcrete under the seabed tunnel environment, which is composed of the following raw materials in parts by weight:

[0007] 480 - 530 parts of ordinary Portland cement, 850 - 900 parts of fine aggregate, 740 - 800 parts of coarse aggregate, 160 - 190 parts of water, 5 - 10 parts of water reducer, 40 - 45 parts of accelerator, 10 - 16 parts of powder material, 15 - 20 parts of corrosion inhibitor;

[0008] The corrosion inhibitor consists of an organic carboxylic acid polymer, an inorganic carbon nanomaterial, and water;

[0009] The organic carboxylic acid polymer is prepared by reacting an organic carboxylic acid with a polyol.

[0010] In some other embodiments, it consists of the following raw materials in parts by weight:

[0011] 500 - 530 parts of ordinary portland cement, 860 - 900 parts of fine aggregate, 740 - 780 parts of coarse aggregate, 160 - 190 parts of water, 9 - 10 parts of water reducing agent, 40 - 45 parts of accelerating agent, 13 - 16 parts of powder material, 15 - 18 parts of corrosion inhibitor;

[0012] The molar ratio of the organic carboxylic acid to the polyol is (1 - 2):(1 - 5);

[0013] Preferably, the molar ratio of the organic carboxylic acid to the polyol is 1:1;

[0014] Or, the mixing mass ratio of the organic carboxylic acid polymer, inorganic carbon nanomaterial, and water in the corrosion inhibitor is (1 - 2):(1 - 2):(20 - 30);

[0015] Preferably, the mixing mass ratio of the organic carboxylic acid polymer, inorganic carbon nanomaterial, and water is 1:1:20.

[0016] In some other embodiments, it consists of the following raw materials in parts by weight:

[0017] 517 parts of ordinary portland cement, 861 parts of fine aggregate, 765 parts of coarse aggregate, 167.5 parts of water, 9.55 parts of water reducing agent, 42.4 parts of accelerating agent, 13 parts of powder material, 18 parts of corrosion inhibitor;

[0018] Or, the organic carboxylic acid is one or more of polyacrylic acid, polymethacrylic acid, benzoic acid,

[0019] Or, the polyol is one or more of polyethylene glycol and polypropylene glycol;

[0020] Or, the inorganic carbon nanomaterial is one or more of graphene, carbon nanotubes, and carbon quantum dots.

[0021] In some other embodiments, the powder material consists of sulfoaluminate cement, ordinary portland cement, and fly ash;

[0022] Preferably, the mixing mass ratio of the sulfoaluminate cement, ordinary portland cement, and fly ash in the powder material is (6 - 8):(6 - 8):(2 - 4);

[0023] Further preferably, the mixing mass ratio of sulfoaluminate cement, ordinary Portland cement and fly ash in the powder material is 7:7:3.

[0024] In some other embodiments, the fine aggregate is medium sand with a fineness modulus of 2.5 - 3.0, and the proportion of particles smaller than 0.075 mm in the fine aggregate does not exceed 20%;

[0025] Or, the coarse aggregate is crushed stone with a particle size of 5 - 10 mm;

[0026] Or, the water reducing agent is a polycarboxylate water reducing agent;

[0027] Or, the accelerating agent is an alkali-free accelerating agent;

[0028] Or, the grade of the Portland cement is type P·O42.5;

[0029] Preferably, the water reducing rate of the polycarboxylate water reducing agent is 22 - 30%;

[0030] Preferably, the alkali-free accelerating agent is an aluminum sulfate-based alkali-free accelerating agent.

[0031] In a second aspect, the present invention provides a method for preparing the quick-setting and corrosion-resistant shotcrete in the undersea tunnel environment described in the first aspect, including the following steps:

[0032] S1. Mix ordinary Portland cement, fine aggregate, coarse aggregate and powder material to obtain a first material;

[0033] S2. Mix water, water reducing agent and corrosion inhibitor to obtain a second material;

[0034] S3. After mixing the first material and the second material, obtain premixed concrete; during the construction process, mix the premixed concrete with the accelerating agent immediately and then spray it onto the construction surface.

[0035] In some other embodiments, in S2, the preparation method of the corrosion inhibitor includes the following steps:

[0036] React an organic carboxylic acid solution, polyhydric alcohol and catalyst to obtain an organic carboxylic acid polymer; mix the organic carboxylic acid polymer, inorganic carbon nanomaterial and water to obtain the corrosion inhibitor;

[0037] The temperature of the reaction is 50 - 150 °C, and the reaction time is 10 - 16 h;

[0038] The mixing is carried out by stirring at 1500 - 1800 r / min for 4 - 6 h.

[0039] In some other embodiments, in the preparation method of the erosion inhibitor, the organic carboxylic acid is one or more of polyacrylic acid, polymethacrylic acid, and benzoic acid;

[0040] The solvent of the organic carboxylic acid solution is one of toluene and ethanol;

[0041] The concentration of the organic carboxylic acid solution is 0.1 - 0.3 mol / L;

[0042] The polyol is one or more of polyethylene glycol and polypropylene glycol;

[0043] The catalyst is one or more of toluenesulfonic acid and sulfuric acid;

[0044] The molar ratio of the organic carboxylic acid to the polyol is (1 - 2) : (1 - 5).

[0045] In some other embodiments, in the preparation method of the erosion inhibitor, the mixing mass ratio of the organic carboxylic acid polymer, the inorganic carbon nanomaterial, and water is (1 - 2) : (1 - 2) : (20 - 30);

[0046] The organic carboxylic acid polymer is prepared by catalytic reaction of an organic carboxylic acid and a polyol with a catalyst;

[0047] The inorganic carbon nanomaterial is one or more of graphene, carbon nanotubes, and carbon quantum dots.

[0048] In the third aspect, the present invention provides the application of the quick - setting and erosion - resistant shotcrete in the submarine tunnel construction under the submarine tunnel environment described in the first aspect.

[0049] In the present invention, adding powder materials can effectively improve the early mechanical strength of shotcrete, enhance the cohesiveness and pumpability of shotcrete on the premise of ensuring that the slump meets the requirements. This is because the rapid hardening and early strength characteristics of sulfoaluminate cement in the early strength powder materials meet the conditions of rapid setting required for shotcrete; the slight expansion property of sulfoaluminate cement can well ensure that in the early stage of shotcrete forming, the differential microcracks generated due to temperature changes are offset, and the corrosion resistance and slight alkalinity of sulfoaluminate cement are suitable for construction applications in the undersea tunnel environment; ordinary Portland P·O 52.5 cement just meets the material characteristics of shotcrete due to its early high strength characteristics, and its characteristic of having a relatively high compressive strength after 28 days ensures the stability of the later strength of shotcrete, preventing the occurrence of the phenomenon of compressive strength retrogression of shotcrete. It also has the characteristic of low heat of hydration, avoiding the generation of extra heat on the basis of rapid heat release after shotcrete is mixed with the accelerator; the addition of fly ash fills the micro-gaps between cement particles, enhances the cohesiveness of shotcrete, ensures the early strength of shotcrete and inhibits the generation of microcracks.

[0050] In the present invention, by adding a corrosion inhibitor, the loss of calcium ions caused by seawater erosion after shotcrete forming is reduced to ensure the strength of shotcrete, because the loss is too large in the later stage, which affects the project quality. The organic carboxylic acid polymer in the corrosion inhibitor regulates its hydrophobicity by adjusting the number, distribution, main chain and side chain structure of its carboxylic acid groups and the pH value, so as to ensure that after shotcrete forming, it has a certain hydrophobicity inside to reduce the erosion of seawater on shotcrete. To ensure hydrophobicity, it is carried out by adjusting the low carboxylic acid group density, hydrophobic main chain, hydrophobic side chain and low pH value. And the carbon nanomaterials have strong hydrophobicity. By adding carbon nanomaterials, the hydrophobic performance of shotcrete is further enhanced, thus ensuring that shotcrete has a certain corrosion resistance.

[0051] In the preparation method of rapid-setting and corrosion-resistant shotcrete in the undersea tunnel environment, the first material and the second material are uniformly mixed to obtain premixed concrete; during the construction process, the premixed concrete is instantaneously mixed with an accelerator and then sprayed onto the construction surface.

[0052] The beneficial effects of the present invention:

[0053] 1. In the present invention, by adding powder materials, the early strength of shotcrete is enhanced, the bonding force of shotcrete is improved, and the rebound rate of shotcrete is reduced.

[0054] 2. In the present invention, by adding a corrosion inhibitor with a hydrophobic effect, the ability of shotcrete to resist calcium corrosion is enhanced, and the durability of shotcrete is enhanced.

[0055] 3. The shotcrete of the present invention has improved crack resistance and durability compared to ordinary shotcrete, can better adapt to the complex construction environment of the submarine tunnel, and improve the service life of the tunnel lining in the submarine tunnel environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The schematic drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0057] Figure 1 It is the process flow chart of the preparation of the shotcrete in Example 6 of the present invention;

[0058] Figure 2 It is the compressive strength ratio of the shotcrete after corrosion in Examples 1-6 of the present invention;

[0059] Figure 3 It is the surrounding rock face before construction on-site in Example 6 of the present invention;

[0060] Figure 4 It is the picture of the actual construction process in Example 6 of the present invention;

[0061] Figure 5 It is the state diagram of the shotcrete prepared in Example 6 of the present invention sprayed into the tunnel. DETAILED DESCRIPTION OF THE INVENTION

[0062] At present, after the shotcrete used in the submarine tunnel is sprayed, corrosion phenomenon is likely to occur in the short term. The present invention provides a shotcrete suitable for rapid hardening and corrosion resistance in the submarine tunnel, its preparation method and application, which have the advantages of adapting to the construction environment of the submarine tunnel, early strength, low rebound, high corrosion resistance performance, etc.; the shotcrete with early strength can limit the generation and development of microcracks at the earliest stage of concrete forming, and avoid the penetration of erosive seawater; the shotcrete with corrosion resistance can resist the erosion of seawater through the action of internal hydrophobic materials in the later stage. The present invention adds early strength powder materials to ensure its early strength and reduce rebound, and adds corrosion inhibitors to enhance the corrosion resistance performance of the shotcrete. The shotcrete provided by the present invention has a good effect in resisting concrete corrosion.

[0063] The following will further describe the present invention in detail in combination with the specific embodiments:

[0064] Among them, the portland cement is P·O42.5 portland cement; the fine aggregate is medium sand with a fineness modulus of 2.5 - 3.0, and the proportion of particles smaller than 0.075mm in the fine aggregate does not exceed 20%; the coarse aggregate is 5 - 10mm crushed stone; the water is municipal supply tap water; the water reducing agent is a polycarboxylate water reducing agent, the manufacturer is Jiangsu Sobute New Materials Co., Ltd., the product model is PCA-10 series polycarboxylate superplasticizer, and the water reducing rate is 22 - 30%; the non-alkali accelerating agent is an aluminum sulfate-based non-alkali accelerating agent, the manufacturer is Jiangsu Sobute New Materials Co., Ltd., and the product model is SBT-N(Ⅱ) liquid accelerating agent (non-alkali type).

[0065] The preparation method of the powder material is as follows:

[0066] Weigh the sulfoaluminate cement, ordinary portland cement and fly ash according to the mass ratio of (6 - 8):(6 - 8):(2 - 4), and then place them in a clean and water-free mixer and dry mix for at least 2 minutes to make it.

[0067] More specifically, the powder material is made by weighing the mixed mass ratio of sulfoaluminate cement, ordinary portland cement and fly ash as 7:7:3, placing it in a clean and water-free mixer, and dry mixing for 3 minutes.

[0068] The preparation method of the corrosion inhibitor is as follows:

[0069] React the organic carboxylic acid solution, polyhydric alcohol and catalyst to obtain an organic carboxylic acid polymer; mix the organic carboxylic acid polymer, inorganic carbon nanomaterial and water to obtain the corrosion inhibitor;

[0070] The temperature of the reaction is 50 - 150°C, and the reaction time is 10 - 16h;

[0071] The mixing is carried out by stirring at 1500 - 1800r / min for 4 - 6h.

[0072] More specifically, the organic carboxylic acid is benzoic acid (C7H6O2), the solvent of the organic carboxylic acid solution is toluene; the concentration of the organic carboxylic acid solution is 0.2mol / L;

[0073] The polyhydric alcohol is polypropylene glycol 400 (HO-(CH2CH2O) n -H);

[0074] The catalyst is p-toluenesulfonic acid;

[0075] The molar ratio of the organic carboxylic acid to the polyhydric alcohol is 1:2.

[0076] The mixing mass ratio of the organic carboxylic acid polymer, inorganic carbon nanomaterial and water is 1:1:20.

[0077] The inorganic carbon nanomaterial is graphene carbon quantum dots, and the concentration is 1 mg / ml. The water is distilled water.

[0078] The organic solvent toluene and the organic carboxylic acid benzoic acid are weighed in a molar ratio, stirred evenly, and then heated to 120°C, and then polyol polypropylene glycol (molecular weight 400) and catalyst toluenesulfonic acid are added to react for about 14 hours to prepare a polymer. The prepared organic carboxylic acid polymer and inorganic carbon nanomaterial are then dissolved in an aqueous solution, stirred at 1600 r / min for about 5 hours, and the corrosion inhibitor is prepared after being evenly dispersed.

[0079] Embodiment 1:

[0080] A quick-setting anti-corrosion shotcrete suitable for use in a submarine tunnel environment, as shown in Table 1, is composed of the following raw materials in parts by weight:

[0081] Portland cement: 514 parts; fine aggregate (fineness modulus is 2.5, and particles smaller than 0.075 mm account for 15%): 882.5 parts; coarse aggregate: 765 parts; water: 180 parts; polycarboxylic acid water reducer (water reduction rate is 25%): 9.55 parts; alkali-free accelerator: 42.4 parts; powder material: 0 parts; corrosion inhibitor: 0 parts.

[0082] A method for preparing quick-setting anti-corrosion shotcrete suitable for use in a submarine tunnel environment, comprising the following steps:

[0083] S1. Put cement, fine aggregate and coarse aggregate into a mixer and dry mix for 5 minutes to obtain a first material;

[0084] S2. The polycarboxylate water reducer is added to the water and mixed evenly to obtain a second material;

[0085] S3. Add the second material into the first material and mix them thoroughly to obtain premixed concrete. During the construction process, quickly pour the premixed concrete into the alkali-free quick-setting agent, stir for 15 seconds and then stop stirring immediately, and the sprayed concrete is obtained after exiting the mixer.

[0086] Put the shotcrete into the prepared 100×100×100mm triple mold and vibrate it thoroughly. After the vibration is completed, cover the casting surface with plastic wrap in time to prevent moisture loss. After one day of standard curing, demould it and move the test block immediately into the standard curing room for subsequent tests.

[0087] Embodiment 2:

[0088] Different from Example 1, a quick-setting anti-corrosion shotcrete suitable for use in a submarine tunnel environment is composed of the following raw materials in parts by weight, as shown in Table 1:

[0089] Portland cement: 530 parts; fine aggregate: 861 parts; coarse aggregate: 765 parts; water: 185.5 parts; polycarboxylate water reducer: 9.55 parts; alkali-free accelerating agent: 42.4 parts; powder material: 0 parts; corrosion inhibitor: 0 parts.

[0090] The preparation method is the same as that of Example 1.

[0091] Example 3:

[0092] Different from Example 1, a rapid-setting and corrosion-resistant shotcrete applicable to the undersea tunnel environment, as shown in Table 1, is composed of the following raw materials in parts by weight:

[0093] Portland cement: 517 parts; fine aggregate: 861 parts; coarse aggregate: 765 parts; water: 185.5 parts; polycarboxylate water reducer: 9.55 parts; alkali-free accelerating agent: 42.4 parts; powder material: 13 parts; corrosion inhibitor: 0 parts.

[0094] The difference in the preparation method from Example 1 is that in S1, when preparing the first material, the cement, fine aggregate, coarse aggregate and powder material are mixed evenly to obtain the first material; the remaining steps are the same as those in Example 1.

[0095] Example 4

[0096] Different from Example 1, a rapid-setting and corrosion-resistant shotcrete applicable to the undersea tunnel environment, as shown in Table 1, is composed of the following raw materials in parts by weight:

[0097] Portland cement: 514.4 parts; fine aggregate: 861 parts; coarse aggregate: 765 parts; water: 185.5 parts; polycarboxylate water reducer: 9.55 parts; alkali-free accelerating agent: 42.4 parts; powder material: 15.6 parts; corrosion inhibitor: 0 parts.

[0098] The difference in the preparation method from Example 1 is that in S1, when preparing the first material, the cement, fine aggregate, coarse aggregate and powder material are mixed evenly to obtain the first material; the remaining steps are the same as those in Example 1.

[0099] Example 5:

[0100] Different from Example 1, a rapid-setting and corrosion-resistant shotcrete applicable to the undersea tunnel environment, as shown in Table 1, is composed of the following raw materials in parts by weight:

[0101] Portland cement: 530 parts; fine aggregate: 861 parts; coarse aggregate: 765 parts; water: 167.5 parts; polycarboxylate water reducer: 9.55 parts; alkali-free accelerating agent: 42.4 parts; powder material: 0 parts; corrosion inhibitor: 18 parts.

[0102] The preparation method is different from that of Example 1. In S2, when preparing the second material, water, water reducing agent and erosion inhibitor material are mixed evenly to obtain the second material; the remaining steps are the same as those of Example 1.

[0103] Example 6:

[0104] Different from Example 1, a rapid-setting and erosion-resistant shotcrete applicable to the undersea tunnel environment, as shown in Table 1, is composed of the following raw materials in parts by weight:

[0105] Portland cement: 517 parts; fine aggregate: 861 parts; coarse aggregate: 765 parts; water: 167.5 parts; polycarboxylate water reducing agent: 9.55 parts; alkali-free rapid-setting agent: 42.4 parts; powder material: 13 parts; erosion inhibitor: 18 parts.

[0106] The preparation method is as Figure 1 shown. Different from Example 1, in S1, when preparing the first material, cement, fine aggregate, coarse aggregate and powder material are mixed evenly to obtain the first material;

[0107] In S2, when preparing the second material, water, water reducing agent and erosion inhibitor material are mixed evenly to obtain the second material; the remaining steps are the same as those of Example 1.

[0108] Example 7:

[0109] Different from Example 1, a rapid-setting and erosion-resistant shotcrete applicable to the undersea tunnel environment, as shown in Table 1, is composed of the following raw materials in parts by weight:

[0110] Portland cement: 517 parts; fine aggregate: 861 parts; coarse aggregate: 765 parts; water: 185.5 parts; polycarboxylate water reducing agent: 9.55 parts; alkali-free rapid-setting agent: 42.4 parts; powder material: 13 parts; erosion inhibitor: 0 part.

[0111] The preparation method is different from that of Example 1. In S1, when preparing the first material, cement, fine aggregate, coarse aggregate and powder material are mixed evenly to obtain the first material; among them, the mixing ratio of the powder material is changed to the mixing mass ratio of sulfoaluminate cement and fly ash of 7:3; the remaining steps are the same as those of Example 1.

[0112] Table 1 Raw material composition of rapid-setting and erosion-resistant shotcrete applicable to the undersea tunnel environment

[0113]

[0114]

[0115] Performance test

[0116] The shotcrete prepared in Examples 1-7 was subjected to compressive strength testing. The testing standard for compressive strength was carried out strictly in accordance with the national standard GB / T 50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete". The workability test was conducted on the shotcrete before adding the accelerator, strictly in accordance with the national standard GB / T50080-2016 "Standard for Test Methods of Properties of Ordinary Concrete Mixtures". The test results are shown in Tables 2-5.

[0117] Table 2 Fresh Properties of Concrete

[0118] Number Slump (mm) Spread (mm) Air content (%) <![CDATA[Unit weight (kg / m 3 )]]> Example 1 220 500 3.0 2267 Example 2 215 510 2.6 2300 Example 3 220 480 3.0 2271 Example 4 210 450 2.2 2314 Example 5 200 470 1.9 2328 Example 6 190 450 2.8 2286 Example 7 180 420 2.6 2310

[0119] As can be seen from Table 2, for the fresh properties of Examples 1-7, and from the states observed during the actual on-site mixing process, adding powder materials and corrosion inhibitors to the concrete has no obvious effect on the air content and unit weight of the concrete (a difference in air content of 1.5% is regarded as a significant difference). However, different ratios of powder materials have a greater impact on the slump and spread. All data meet the design requirements, and the optimized mix proportion of the shotcrete meets the construction requirements.

[0120] Table 3 Compressive Strength of Shotcrete after 1d of Molding

[0121]

[0122]

[0123] The compressive strength of different groups of concrete was tested, as shown in Table 3. By comparison, it can be found that the compressive strength of the experimental mix proportion (Example 2) of the concrete reached 19.4 MPa, which is higher than the compressive strength of 17.8 MPa of the on-site mix proportion of the concrete (Example 1), proving the excellent effect of the experimental mix proportion and the correctness of the mix proportion adjustment. After using different anti-corrosion technologies, the compressive strength of the concrete also increased. After using the 2.5% powder anti-corrosion enhancement technology, the compressive strength of the concrete increased most significantly, by 13.9%. After using 3% of the powder anti-erosion inhibitor, the compressive strength of the concrete increased by 10.8%, proving that using the powder anti-erosion inhibitor has a certain effect on improving the early strength of the shotcrete and meets the on-site construction requirements. After using 18 kg / m 3 of the liquid anti-erosion inhibitor, the compressive strength of the shotcrete increased by 8.3%. Using the liquid corrosion inhibition technology also has a certain effect on improving the early strength of the shotcrete and meets the on-site construction requirements.

[0124] Table 4 Compressive Strength of Shotcrete after 14d of Molding

[0125]

[0126] The compressive strength of shotcrete after 14 days of corrosion was tested for different groups of concrete, and the influence of the anti-corrosion technology used on site on the anti-corrosion performance of shotcrete was compared. The compressive strength is shown in Table 4. It can be found from the comparison that after 14 days of standard curing, the compressive strength of the blank group of shotcrete has reached 35.3 MPa, and the compressive strength of the optimized shotcrete is 38.3 MPa. Whether at the 1-day age or the 14-day age, the compressive strength of the optimized mix ratio is greater than the preliminary mix ratio, which proves the effect of the mix ratio optimization. After using the powder anti-corrosion material, the compressive strength also reached 47.9 MPa. After using the corrosion inhibitor, the mechanical properties of the shotcrete are 38.3 MPa. Under the condition of compound use of the powder material and the corrosion inhibitor, the compressive strength of the concrete is 38.8 MPa, and the compressive strength of the concrete is close to that of the optimized concrete, which proves that there is no negative effect on the mechanical properties of the shotcrete under this type of accelerator system.

[0127] The compressive strength of shotcrete after corrosion is as follows Figure 2 As shown. It can be found from the comparison that after adding the powder material, there is no obvious improvement in the anti-corrosion performance of the shotcrete. After 14 days of corrosion of the blank group of concrete, the strength loss rates are 4.6% and 11.9%. After using the powder anti-corrosion technology, the strength loss rates of the concrete are 6.5% and 5.6% respectively. After using the corrosion inhibitor, the corrosion strength of the shotcrete has increased instead. The compressive strengths of the concrete in Example 5 and Example 6 have increased by 8.9% and 10.1% respectively. This may be because after using the corrosion inhibitor, the dissolution of calcium ions is inhibited, and at the same time, sulfate ions in the soaking solution diffuse into the concrete interior, generating ettringite, resulting in an increase in the compactness of the concrete, and thus the compressive strength has increased. There is little difference in the mechanical properties and durability performance between Example 6 and Example 7, but the fluidity of Example 7 is not as good as that of Example 6.

[0128] According to the above laboratory shotcreting test results, the shotcrete prepared in Example 6 of the present invention was applied to the actual construction area of the service tunnel of the Second Subsea Tunnel in Jiaozhou Bay, with the mileage label of FWK10+641~643. There is a lot of water gushing and seepage at the construction site, and the surrounding rock grade is 4. Figure 3 This is the surrounding rock face before construction at the site. From Figure 3 it can be seen that there is water seepage gushing out from the construction surface and gathering at the bottom of the face; a large amount of gravel falls to the bottom during the process of cleaning the face and installing the steel arch, and the surrounding rock is not stable, and the danger level at the construction site is relatively high.

[0129] Figure 4 This is the actual construction process diagram of Example 6. From Figure 4It can be seen that during the construction process, both the powder material and the liquid material are precisely weighed and fed by special personnel to ensure construction in strict accordance with the mix ratio. Moreover, the work performance of the concrete is inspected before it enters the hole after mixing and when the concrete enters the shotcrete machine to ensure that it meets the construction requirements and prevent the occurrence of illegal construction phenomena.

[0130] Large-panel samples of the shotcrete in Example 6 were taken for later tests, and the results are shown in Table 5.

[0131] Table 5 Compressive strength of the shotcrete in Field Example 6

[0132] Age 1d 3d 14d 28d 56d Compressive strength / MPa 15.33 21.63 36.97 39.65 39.2

[0133] According to the field spraying results in Table 5, the compressive strengths of the shotcrete prepared in Example 6 at each age meet the design requirements.

[0134] Figure 5 This is the state diagram of the shotcrete prepared in Example 6 of the present invention sprayed into the tunnel. From Figure 5 it can be seen that water seepage and a large amount of white substances precipitated in the original shotcrete soon after construction, while there is no large-area water penetration or white substance precipitation in the shotcrete of the present invention.

[0135] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A quick-setting and corrosion-resistant shotcrete for undersea tunnel environment, characterized in that, It consists of the following components by weight: 480 - 530 parts of ordinary Portland cement, 850 - 900 parts of fine aggregate, 740 - 800 parts of coarse aggregate, 160 - 190 parts of water, 5 - 10 parts of water reducing agent, 40 - 45 parts of accelerating agent, 10 - 16 parts of powder material, 15 - 20 parts of corrosion inhibitor; The corrosion inhibitor consists of an organic carboxylic acid polymer, an inorganic carbon nanomaterial and water; The organic carboxylic acid polymer is prepared by reacting an organic carboxylic acid with a polyhydric alcohol.

2. The quick-setting and corrosion-resistant shotcrete under the seabed tunnel environment according to claim 1, wherein It consists of the following raw materials by weight: 500 - 530 parts of ordinary Portland cement, 860 - 900 parts of fine aggregate, 740 - 780 parts of coarse aggregate, 160 - 190 parts of water, 9 - 10 parts of water reducing agent, 40 - 45 parts of accelerating agent, 13 - 16 parts of powder material, 15 - 18 parts of corrosion inhibitor; The molar ratio of the organic carboxylic acid to the polyhydric alcohol is (1 - 2):(1 - 5); Or, the mixing mass ratio of the organic carboxylic acid polymer, the inorganic carbon nanomaterial and water in the corrosion inhibitor is (1 - 2):(1 - 2):(20 - 30); Preferably, the mixing mass ratio of the organic carboxylic acid polymer, the inorganic carbon nanomaterial and water is 1:1:

20.

3. The quick-setting and corrosion-resistant shotcrete under the seabed tunnel environment according to claim 1, wherein It consists of the following raw materials by weight: 517 parts of ordinary Portland cement, 861 parts of fine aggregate, 765 parts of coarse aggregate, 167.5 parts of water, 9.55 parts of water reducing agent, 42.4 parts of accelerating agent, 13 parts of powder material, 18 parts of corrosion inhibitor; Or, the organic carboxylic acid is one or more of polyacrylic acid, polymethacrylic acid, benzoic acid, etc. Or, the polyhydric alcohol is one or more of polyethylene glycol and polypropylene glycol; Or, the inorganic carbon nanomaterial is one or more of graphene, carbon nanotubes and carbon quantum dots.

4. The quick-setting and corrosion-resistant shotcrete under the seabed tunnel environment according to claim 1, wherein, The powder material consists of sulfoaluminate cement, ordinary Portland cement and fly ash; Preferably, the mixing mass ratio of sulfoaluminate cement, ordinary Portland cement and fly ash in the powder material is (6 - 8):(6 - 8):(2 - 4); More preferably, the mixing mass ratio of sulfoaluminate cement, ordinary Portland cement and fly ash in the powder material is 7:7:

3.

5. The quick-setting and corrosion-resistant shotcrete under the seabed tunnel environment according to claim 1, characterized in that, The fine aggregate is medium sand with a fineness modulus of 2.5 - 3.0, and the proportion of particles smaller than 0.075mm in the fine aggregate does not exceed 20%; Or, the coarse aggregate is crushed stone with a particle size of 5 - 10mm; Or, the water reducing agent is a polycarboxylate water reducing agent; Or, the accelerating agent is an alkali - free accelerating agent; Or, the grade of the Portland cement is type P·O42.5; Preferably, the water reducing rate of the polycarboxylate water reducing agent is 22 - 30%; Preferably, the alkali - free accelerating agent is an aluminum sulfate - type alkali - free accelerating agent.

6. A preparation method of the quick-setting and corrosion-resistant shotcrete under the seabed tunnel environment according to any one of claims 1-5, characterized in that, It includes the following steps: S1. Mix ordinary Portland cement, fine aggregate, coarse aggregate and powder material to obtain the first material; S2. Mix water, water reducing agent and corrosion inhibitor to obtain the second material; S3. After mixing the first material and the second material, obtain the premixed concrete; during the construction process, mix the premixed concrete with the accelerating agent immediately and then spray it onto the construction surface.

7. The preparation method of the quick-setting and corrosion-resistant shotcrete under the undersea tunnel environment according to claim 6, wherein, In S2, the preparation method of the corrosion inhibitor includes the following steps: React an organic carboxylic acid solution, a polyol, and a catalyst to obtain an organic carboxylic acid polymer; mix the organic carboxylic acid polymer, an inorganic carbon nanomaterial, and water to obtain a corrosion inhibitor; The temperature of the reaction is 50 - 150 °C, and the reaction time is 10 - 16 h; The mixing is carried out by stirring at 1500 - 1800 r / min for 4 - 6 h.

8. The preparation method of the quick-setting and corrosion-resistant shotcrete under the seabed tunnel environment according to claim 7, characterized in that In the preparation method of the corrosion inhibitor, the organic carboxylic acid is one or more of polyacrylic acid, polymethacrylic acid, and benzoic acid; The solvent of the organic carboxylic acid solution is one of toluene and 5 - aminosalicylic acid; The concentration of the organic carboxylic acid solution is 0.1 - 0.3 mol / L; The polyol is one or more of polyethylene glycol and polypropylene glycol; The catalyst is one or more of p - toluenesulfonic acid and sulfuric acid; The molar ratio of the organic carboxylic acid to the polyol is (1 - 2):(1 - 5).

9. The preparation method of the quick-setting and corrosion-resistant shotcrete in the undersea tunnel environment according to claim 7, characterized in that In the preparation method of the corrosion inhibitor, the mass ratio of the organic carboxylic acid polymer, the inorganic carbon nanomaterial, and water is (1 - 2):(1 - 2):(20 - 30); The inorganic carbon nanomaterial is one or more of graphene, carbon nanotubes, and carbon quantum dots.

10. Application of the rapid - setting and corrosion - resistant shotcrete according to any one of claims 1 - 5 in the construction of a submarine tunnel.

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