A premixed tunnel secondary lining concrete grouting material and its flow production method

Abstract

This invention belongs to the technical field of railway tunnel secondary lining concrete grouting materials, specifically relating to a pre-mixed tunnel secondary lining concrete grouting material and its flow-type production method. It comprises the following raw materials in parts by weight: 44-46 parts silicate cement, 43-46 parts manufactured sand, 9-11 parts fly ash, 0.18-0.2 parts polycarboxylate superplasticizer, 0.024-0.026 parts defoamer, 0.02-0.04 parts expansion agent, 0.03-0.05 parts rheology modifier, and 0.01-0.03 parts boric acid. The tunnel secondary lining concrete grouting material prepared by this invention exhibits improved retarding effect, water retention effect, and flexural and compressive strength, contributing to the overall improvement of the tunnel grouting material's performance.

Description

Technical Field

[0001] This invention belongs to the field of railway tunnel secondary lining concrete grouting material technology, specifically relating to a pre-mixed tunnel secondary lining concrete grouting material and its flow production method. Background Technology

[0002] Currently, tunnels are a major component of railway engineering, and the primary construction method is drill-and-blast. After excavation, initial support, waterproofing membrane, and secondary lining concrete are constructed. However, due to factors such as concrete performance, construction techniques, and common quality defects, voids often appear behind the secondary lining concrete, preventing effective support. To address this issue, various construction projects now use pre-embedded grouting pipes for secondary lining grouting. Currently, cement grout is commonly used, along with ordinary grouting materials prepared with a certain proportion of quartz sand, cement, fly ash, and expansion agents. These materials generally suffer from drawbacks such as high cost, low early strength, long setting time, and poor bonding with the secondary lining. This falls short of the high quality requirements of the project, leading to the replacement of some railway tunnels that failed static acceptance tests and post-opening inspections, posing potential risks to project quality and operational safety.

[0003] In view of the above problems, a new material is needed to solve the problem of high performance, high strength and high economy of grouting filler after the secondary lining concrete of tunnels has become voided. Summary of the Invention

[0004] To address the issues of high performance, high strength, and high economy in grouting fillers after voids in tunnel secondary lining concrete, this invention provides a pre-mixed tunnel secondary lining concrete grouting material and its flow-type production method.

[0005] The present invention adopts the following technical solution: a premixed tunnel secondary lining concrete grouting material, comprising the following raw materials in parts by weight: 44-46 parts of silicate cement, 43-46 parts of manufactured sand, 9-11 parts of fly ash, 0.18-0.2 parts of polycarboxylate superplasticizer, 0.024-0.026 parts of defoamer, 0.02-0.04 parts of expansion agent, 0.03-0.05 parts of rheology modifier, and 0.01-0.03 parts of boric acid.

[0006] In some embodiments, the composition includes 0.19 parts of polycarboxylate superplasticizer, 0.025 parts of defoamer, 0.03 parts of expansion agent, 0.04 parts of rheology modifier, and 0.02 parts of boric acid.

[0007] In some embodiments, the defoamer is composed of silica and polypropylene glycol monobutyl ether in a mass ratio of 35-40:60-65.

[0008] In some embodiments, the expanding agent is composed of heavy calcium carbonate powder and casein in a mass ratio of 15-20:75-80.

[0009] In some embodiments, the rheology modifier is composed of heavy calcium carbonate powder and polysaccharide polymer in a mass ratio of 5-20:80-95.

[0010] In some embodiments, the cement is low-alkali silicate cement with an alkali content of <0.06%.

[0011] In some embodiments, the parent rock of the manufactured sand is limestone, the sub-blue value of the stone powder is not greater than 1.2, and it is made by mixing 40-70 mesh and 70-120 mesh in a 4:6 ratio.

[0012] A flow-type production method for pre-mixed tunnel secondary lining concrete grouting material includes:

[0013] S100: Fly ash is loaded into the batching area, and other materials are loaded into the auxiliary feeding area for preparation.

[0014] S200: Input the mixing ratio of the primary mixture. Fly ash is directly fed into the mixer, and other components are added in the following order: fly ash, polycarboxylate superplasticizer, defoamer, rheology modifier and boric acid.

[0015] S300: After forced mixing, the mixture is conveyed to the unloading area in a ton bag and then transported by forklift to the storage area for inspection and use after passing inspection.

[0016] S400: Empty the fly ash from the batching area, and use a flexible sand suction machine to suck the manufactured sand into the batching silo. Place the qualified primary mixture in the auxiliary feeding area.

[0017] S500: In the control area, according to the input grout mix ratio, cement and manufactured sand are directly fed into the mixer. The primary mixture is manually fed from the auxiliary feeding area, and the feeding order is cement, manufactured sand, and primary mixture.

[0018] S600: After the powders are forcibly mixed evenly, the grouting material is conveyed to the unloading area, packaged by a pressure-type quantitative baler, and transported by forklift to the storage area for inspection and use.

[0019] In some embodiments, the main mixer in the mixing zone is a forced horizontal mixer with an automatic metering device, and the mixing time for one batch of mixed material is not less than 15 minutes, while the mixing time for grouting material is not less than 10 minutes.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The pre-mixed tunnel lining concrete grouting material and its flowable production method provided by this invention are prepared using ordinary Portland cement, manufactured sand, and water as main raw materials. The tunnel lining concrete grouting material produced by this invention exhibits improved flowability, water retention, flexural strength, and compressive strength, contributing to the overall improvement of the tunnel grouting material's performance. The flowable production method employed in this invention solves the problem of dual-use of fly ash and manufactured sand in a single silo by using a dual-mode horizontal batching silo; it solves the problem of separate metering and mixing operations by integrating metering and mixing into a single design; and it achieves on-site preparation and production of grouting material by integrating all modules of the production line for vehicle-mounted transportation. This allows for rapid adjustment of product performance based on site conditions, better serving the construction site. Attached Figure Description

[0022] Figure 1 Schematic diagram of the production process of primary mixture of grouting material for tunnel secondary lining concrete;

[0023] Figure 2 A production process diagram for tunnel secondary lining concrete grouting material;

[0024] Figure 3 This is a top view of the present invention;

[0025] Figure 4 This is a front view of the present invention;

[0026] Figure 5 This is a front view of the transportation status of the present invention;

[0027] Figure 6 This is a top view schematic diagram of the transportation status of the present invention;

[0028] Figure 7 This is a schematic diagram of a horizontal batching silo.

[0029] Among them, 1 is the control room, 2 is the manual feeding hopper, 3 is the manual feeding screw conveyor, 4 is the forced mixer, 5 is the finished product screw conveyor, 6 is the master material conveying pipe, 7 is the dust collector, 8 is the pressurized quantitative baler, 9 is the air compressor, 10 is the air storage tank, 11 is the horizontal batching silo, 13 is the feeding screw conveyor, 14 is the main unit fixing pad, 15 is the outer packaging, 16 is the weight sensor, 17 is the working platform, 11.1 is the base, 11.2 is the hydraulic jack, 11.3 is the positioning pin, 11.4 is the support leg, 11.5 is the tank body, 11.6 is the dust collector, 11.7 is the connector, 11.8 is the sand suction device, 11.9 is the material discharge rack, 11.10 is the feed pipe, and 11.11 is the hydraulic pump station. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] To investigate the effects of the amount of manufactured sand and various chemical reagents added on the performance and strength of tunnel grouting materials, performance tests were conducted on the samples through comparative experiments.

[0032] For fluidity determination, refer to the "Technical Specification for Application of Cement-based Grouting Materials" (GB / T50448-2015) and use calipers to measure the maximum diffusion diameter of the bottom surface and the diameter in the direction perpendicular to it. Calculate the average value as the initial value of fluidity. The test results should be accurate to 1 mm.

[0033] The vertical expansion rate shall be in accordance with the "Technical Specification for Application of Cement-based Grouting Materials" (GB / T50448-2015) and the instruments and equipment for the dial gauge method shall comply with the relevant provisions of the current national standard "Technical Specification for Application of Concrete Admixtures" (GB50119-2013).

[0034] Flexural and compressive strength tests: The flexural and compressive strengths of the grouting material were measured at 1d, 3d, and 28d. The specimen preparation and testing methods followed GB / T17671-2020, "Test Method for Strength of Cement Mortar (ISO Method)". Rectangular blocks with dimensions of 40mm × 40mm × 160mm were prepared, and flexural and compressive strength tests were conducted at the corresponding 1d, 3d, and 28d ages using the traditional center-loading method.

[0035] In the following examples

[0036] The defoamer is composed of silica and polypropylene glycol monobutyl ether in a mass ratio of 35-40:60-65.

[0037] The expanding agent is composed of heavy calcium carbonate powder and casein, with a mass ratio of 15-20:75-80.

[0038] The rheology modifier is composed of heavy calcium carbonate powder and polysaccharide polymer in a mass ratio of 5-20:80-95.

[0039] Example 1

[0040] A premixed tunnel secondary lining concrete grouting material comprises the following raw materials in parts by weight: 44 parts silicate cement, 43 parts manufactured sand, 9 parts fly ash, 0.18 parts polycarboxylate superplasticizer, 0.024 parts defoamer, 0.02 parts expansion agent, 0.03 parts rheology modifier, and 0.01 parts boric acid.

[0041] To investigate the effects of various materials on the performance and strength of tunnel grouting materials, three groups of grouting material samples A1 were prepared during the preparation process, and the performance of the samples was tested.

[0042]

[0043] Example 2

[0044] A premixed tunnel secondary lining concrete grouting material comprises the following raw materials in parts by weight: 46 parts silicate cement, 46 parts manufactured sand, 11 parts fly ash, 0.2 parts polycarboxylate superplasticizer, 0.026 parts defoamer, 0.04 parts expansion agent, 0.05 parts rheology modifier, and 0.03 parts boric acid.

[0045] To investigate the effects of various materials on the performance and strength of tunnel grouting materials, three groups of grouting material samples (B1) were prepared during the preparation process, and the performance of the samples was tested.

[0046]

[0047] Example 3

[0048] A premixed tunnel secondary lining concrete grouting material comprises the following raw materials in parts by weight: 45 parts silicate cement, 44.5 parts manufactured sand, 10 parts fly ash, 0.19 parts polycarboxylate superplasticizer, 0.025 parts defoamer, 0.03 parts expansion agent, 0.04 parts rheology modifier, and 0.02 parts boric acid.

[0049] To investigate the effects of various materials on the performance and strength of tunnel grouting materials, three groups of grouting material samples (C1) were prepared during the preparation process, and the performance of the samples was tested.

[0050]

[0051] Example 4

[0052] A premixed tunnel secondary lining concrete grouting material comprises the following raw materials in parts by weight: 44 parts silicate cement, 46 parts manufactured sand, 11 parts fly ash, 0.18 parts polycarboxylate superplasticizer, 0.026 parts defoamer, 0.04 parts expansion agent, 0.03 parts rheology modifier, and 0.03 parts boric acid.

[0053] To investigate the effects of various materials on the performance and strength of tunnel grouting materials, three groups of grouting material samples (D1) were prepared during the preparation process, and the performance of the samples was tested.

[0054]

[0055] Example 5

[0056] A premixed tunnel secondary lining concrete grouting material comprises the following raw materials in parts by weight: 45 parts silicate cement, 43 parts manufactured sand, 10 parts fly ash, 0.18 parts polycarboxylate superplasticizer, 0.025 parts defoamer, 0.03 parts expansion agent, 0.03 parts rheology modifier, and 0.01 parts boric acid.

[0057] To investigate the effects of various materials on the performance and strength of tunnel grouting materials, three groups of grouting material samples E1 were prepared during the preparation process, and the performance of the samples was tested.

[0058]

[0059] The polycarboxylate superplasticizer dosage ranged from 0.18 parts to 0.20 parts, which improved the material's fluidity. However, increasing the dosage by 0.20 parts affected the bond strength ratio, so the optimal dosage was determined to be 0.19 parts. The addition of the expansive agent effectively increased the material's vertical expansion rate. However, the expansion rate was too high after adding 0.04 parts, which was not conducive to the structure of the secondary lining concrete. Therefore, the optimal dosage was determined to be 0.03 parts.

[0060] Based on the analysis results, the following performance tests were conducted on the samples: 46 parts silicate cement, 11 parts fly ash, 46 parts manufactured sand, 0.19 parts polycarboxylate superplasticizer, 0.025 parts defoamer, 0.03 parts expansion agent, 0.04 parts rheology modifier, 0.02 parts boric acid, and F1.

[0061]

[0062] The performance results show a significant improvement in fluidity, a moderate expansion rate, and flexural and compressive strength that meet the specifications, with a significant improvement in the bond strength ratio.

[0063] The cement is low-alkali silicate cement with an alkali content of <0.06%.

[0064] The manufactured sand is specially made, with limestone as the parent rock and a sub-blue value of stone powder not exceeding 1.2. It is made by mixing 40-70 mesh and 70-110 mesh in a 4:6 ratio.

[0065] Specifically, the production equipment includes:

[0066] Forced mixer 4;

[0067] Manual feeding hopper 2, which is connected to forced mixer 4 via manual feeding screw conveyor;

[0068] A pressurized quantitative baler 8 is connected to a forced mixer 4 via a finished product screw conveyor 5;

[0069] A horizontal batching silo 11, wherein the feeding screw conveyor 13 of the horizontal batching silo 11 is connected to a forced mixer 4, and the horizontal batching silo 11 is connected to a sand suction machine 12;

[0070] Master material conveying pipe 6, which is connected to the middle of the finished product screw conveyor 5;

[0071] Air compressor 7, which is connected to air tank 10 via an air pipe;

[0072] Vacuum cleaner 9, which is connected to pressurized quantitative packaging machine 8 through a suction pipe, sucks up the dust from pressurized quantitative packaging machine 8;

[0073] Furthermore, a weight sensor 16 is installed on the forced mixer 4.

[0074] Furthermore, it also includes a work platform 17, on which the forced mixer 4 is mounted.

[0075] Furthermore, an upper frame for support is provided on the outside of the work platform 17, and an outer enclosure 15 is provided on the upper frame. The support cylinder of the outer enclosure 15 is connected to the air tank 10 through an air pipe. The compressed air from the air tank 10 drives the support cylinder of the outer enclosure 15 to open and close the outer enclosure 15.

[0076] This device solves the problem of dual-use of fly ash and manufactured sand in a single silo by adopting a dual-mode horizontal batching silo; it achieves separate operations for metering and mixing by integrating metering and mixing into a single design; and it realizes the goal of on-site preparation and production of grouting materials by integrating all modules of the production line for vehicle-mounted transportation and construction. First, the vehicles transporting the production line and the batching silo are positioned side-by-side. Partial outer packaging is opened, the horizontal batching silo is raised, and the manual feeding hopper is positioned and installed. The manual feeding screw conveyor, the feeding screw conveyor, the finished product screw conveyor, and the masterbatch conveying pipe are then installed in sequence. The relevant lines are connected and a trial run is conducted. During production, appropriate amounts of cement and fly ash are fed into the horizontal batching silo, the masterbatch mix ratio is input, and powder is added manually. Other reagents are sequentially added to the forced mixer via the manual feeding silo and mixed for 15 minutes. Then, the intermediate unloading switch of the screw conveyor is opened, and the masterbatch is conveyed to the unloading area in ton bags. A forklift then transports it to the storage area for inspection and approval before use. During the secondary mixing process, the fly ash silo in the batching area is emptied first. The manufactured sand is then sucked into the horizontal batching silo by a flexible sand suction machine. The qualified masterbatch is placed in the manual feeding silo, and the intermediate unloading switch of the screw conveyor in the mixing area is turned off. The grouting material mix ratio is input into the control room. Cement and manufactured sand are directly fed into the main unit of the mixing area by the screw conveyor. The masterbatch is manually fed from the manual feeding area in the following order: cement, manufactured sand, and masterbatch. After all the powders are forcibly mixed evenly, the grouting material is conveyed to the pressurized quantitative baler for packaging. It is then transported by forklift to the storage area for inspection and use after passing inspection.

[0077] like Figure 5 As shown, the horizontal batching bin 11 includes:

[0078] The tank body 11.5 has two compartments inside for storing different ingredients, and multiple support legs 11.4 are provided at the bottom of the tank body 11.5; a height adjustment device is installed at the bottom of each support leg;

[0079] Feed pipe 11.10, one end of which is connected to one of the compartments inside tank 11.5, and the feed pipe 11.10 drives fly ash into tank 11.5 through the air pump on the bulk powder transport vehicle;

[0080] The sand suction device 11.8 is connected to the connector 11.7 and the discharge rack 11.9 respectively via a hose. The connector 11.7 is connected to another compartment inside the tank 11.5.

[0081] Furthermore, the height adjustment device includes:

[0082] The base 11.1 has a cylinder provided at the position corresponding to the support leg 11.4;

[0083] Hydraulic jack 11.2 is installed inside the cylinder of base 11.1, and the upper end of hydraulic jack 11.2 is connected to the bottom of support leg 11.4;

[0084] Hydraulic pump station 11.11 is connected to hydraulic jack 11.2 via high-pressure oil pipe.

[0085] Furthermore, the bottom of the base 11.1 is a solid steel plate, and the cylinder on the base 11.1 is provided with multiple symmetrical circular positioning holes of different heights from top to bottom. The positioning holes on all the cylinders on the base 11.1 are at the same height. According to different requirements, the height positioning pin 11.3 passes through the circular positioning holes on the base 11.1 and the matching positioning holes on the support leg 11.4.

[0086] Furthermore, the tank 11.5 is rectangular and divided into compartments for storage, and the lower part of the tank 11.5 has a conical discharge port.

[0087] Furthermore, the sand suction device 11.8 conveys the manufactured sand into the tank 11.5 through the connector 11.7 via a hose and a spiral steel wire inside the hose.

[0088] Furthermore, the feed pipe 11.10 is connected to fly ash, and the feed rack 11.9 contains manufactured sand.

[0089] The mixing zone is a forced mixer 4, the auxiliary feeding zone is a manual feeding hopper 2, the control zone is a control room 1, the batching zone is a horizontal batching silo 11, and the unloading zone is a pressurized quantitative packaging machine 8.

[0090] A flow-type production method for pre-mixed tunnel secondary lining concrete grouting material includes:

[0091] S100: First, position the vehicles of the transport production line and the batching silo side by side. Open part of the outer packaging, lift the horizontal batching silo, position and install the manual feeding hopper, and then install the manual feeding screw conveyor, the feeding screw conveyor, the finished product screw conveyor, and the master material conveying pipe in sequence. Connect the relevant lines and conduct a trial run. Load fly ash into the batching area, and load water-reducing agent, retarder, defoamer, expanding agent, suspending agent, and quick-setting agent into the auxiliary feeding area for material preparation.

[0092] S200: The control area inputs the mix ratio of the primary mixture. Fly ash is directly fed into the main mixing unit of the mixing zone by the screw conveyor. Other parts are manually operated by the auxiliary feeding area and fed in sequence. The feeding sequence is fly ash, water reducing agent, retarder, defoamer, expanding agent, suspending agent and quick-setting agent.

[0093] S300: After forced mixing, open the screw conveyor middle discharge switch of the mixing zone main unit to convey the mixed material to the unloading zone ton bag, which is then transported by forklift to the storage area for inspection and use after passing inspection;

[0094] S400: Empty the fly ash from the batching area, suck the manufactured sand into the batching silo using the flexible sand suction machine, place the qualified primary mixture in the auxiliary feeding area, and close the intermediate discharge switch of the screw conveyor in the mixing area.

[0095] S500: In the control zone, according to the input secondary mix proportion, cement and manufactured sand are directly fed into the main unit of the mixing zone by the screw conveyor. The primary mix is ​​manually operated by the auxiliary feeding zone. The feeding order is cement, manufactured sand, and primary mix.

[0096] S600: After the powders are forcibly mixed evenly, the grouting material is conveyed to the unloading area, packaged by a pressure-type quantitative baler, and transported by forklift to the storage area for inspection and use.

[0097] The main unit of the mixing zone is a forced horizontal mixer with an automatic metering device. The mixing time for one batch of mixed material is no less than 15 minutes, and the mixing time for grouting material is no less than 10 minutes.

[0098] According to the composition and proportion of the raw materials of the primary mixture, the mixed powder is prepared by uniform mixing. The primary mixture is then compounded again according to the proportion to obtain the grouting material mixture excluding water. On site, water is added first and then the mixed powder, with a water-to-material ratio of 0.17-0.19. The on-site mixing equipment is a high-speed mortar mixer with a speed of not less than 500 rpm, and the grouting machine pressure is not less than 10 MPa with an accuracy of not less than 0.2 MPa.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pre-mixed tunnel secondary lining concrete grouting material, characterized in that, The raw materials include the following parts by weight: 44-46 parts silicate cement, 43-46 parts manufactured sand, 9-11 parts fly ash, 0.18-0.2 parts polycarboxylate superplasticizer, 0.024-0.026 parts defoamer, 0.02-0.04 parts expanding agent, 0.03-0.05 parts rheology modifier, and 0.01-0.03 parts boric acid; The defoamer is composed of silica and polypropylene glycol monobutyl ether in a mass ratio of 35-40:60-65. The expanding agent is composed of heavy calcium carbonate powder and casein, with a mass ratio of 15-20:75-80. The rheology modifier is composed of heavy calcium carbonate powder and polysaccharide polymer in a mass ratio of 5-20:80-95.

2. The pre-mixed tunnel secondary lining concrete grouting material according to claim 1, characterized in that, The composition includes 0.19 parts of polycarboxylate superplasticizer, 0.025 parts of defoamer, 0.03 parts of expanding agent, 0.04 parts of rheology modifier, and 0.02 parts of boric acid.

3. The pre-mixed tunnel secondary lining concrete grouting material according to claim 1, characterized in that, The parent rock of the manufactured sand is limestone, and the methylene blue value of the stone powder is not greater than 1.

2. It is made by mixing 40-70 mesh and 70-120 mesh in a 4:6 ratio.

4. A method for the fluidized production of pre-mixed tunnel secondary lining concrete grouting material according to claim 1, characterized in that, include: S100: Fly ash is loaded into the batching area, and polycarboxylate superplasticizer, defoamer, expanding agent, rheology modifier and boric acid are loaded into the auxiliary feeding area for material preparation; S200: Input the mixing ratio of the primary mixture in the control area. Fly ash is directly fed into the mixer, and other components are added in sequence. The order of addition is fly ash, polycarboxylate superplasticizer, defoamer, expansion agent, rheology modifier and boric acid. S300: After forced mixing, the mixture is conveyed to the unloading area in a ton bag and then transported by forklift to the storage area for inspection and use after passing inspection. S400: Empty the fly ash from the batching area, and use a flexible sand suction machine to suck the manufactured sand into the batching silo. Place the qualified primary mixture in the auxiliary feeding area. S500: In the control area, according to the input grout mix ratio, cement and manufactured sand are directly fed into the mixer. The primary mixture is manually fed from the auxiliary feeding area, and the feeding order is cement, manufactured sand, and primary mixture. S600: After the powders are forcibly mixed evenly, the grouting material is conveyed to the unloading area, packaged by a pressure-type quantitative baler, and transported by forklift to the storage area for inspection and use.

5. The method for producing pre-mixed tunnel secondary lining concrete grouting material according to claim 4, characterized in that, The main unit of the mixing zone is a forced horizontal mixer with an automatic metering device. The mixing time for one batch of mixed material is no less than 15 minutes, and the mixing time for grouting material is no less than 10 minutes.

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