Concrete injection system

Abstract

The utility model discloses a concrete spraying system, and belongs to the field of tunnel concrete spraying construction equipment. The concrete injection system specifically comprises a concrete pumping system, a powder accelerator adding system, an air compressor and a mixing system. The concrete injection system has the specific functions that mixed concrete and a powder accelerator are conveyed to the mixing system through the concrete pumping system and the powder accelerator adding system respectively, and after the concrete and the powder accelerator are fully homogenized and mixed through high-pressure air output by an air compressor, the concrete and the powder accelerator are injected to a tunnel face. According to the utility model, the technical bottleneck that only a liquid accelerator can be adopted for wet spraying of concrete for a long time is broken through, accurate metering and stable conveying of the powder accelerator are realized, and the technical effect that the powder accelerator and the concrete are rapidly, uniformly and fully mixed is achieved; meanwhile, the adverse effect of water in a conventional liquid accelerator on the setting and hardening speed and the bonding strength of the sprayed concrete can be avoided, and the rebound rate of the sprayed concrete is effectively controlled.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of tunnel shotcrete construction equipment, and particularly designs a concrete spraying system. BACKGROUND

[0002] As an important component of the composite lining structure of a tunnel, shotcrete not only needs to bear all loads in the construction stage, but also needs to bear the main load in the operation stage. Currently, alkali accelerators are gradually eliminated in traffic engineering, and liquid accelerators are gradually developing towards alkali-free. Compared with liquid alkali accelerators, the cost of liquid alkali-free accelerators increases significantly, because liquid alkali-free accelerators must add stable components (about 30% of the production cost) to ensure that their stability meets the requirements. At the same time, in order to reduce the viscosity of the accelerator and ensure the pumping effect of the peristaltic pump, the solid content of the liquid accelerator is generally 35% to 45%, and the recommended dosage is 7% to 9%. This means that in addition to the effective accelerating components, the amount of water introduced into the liquid accelerator accounts for about 3.85% to 5.85% of the total amount of cementitious materials of the concrete, which is equivalent to increasing the water-binder ratio of the shotcrete by 0.04 to 0.06, which will seriously affect the setting time, strength development and durability of the shotcrete. Under the condition of high-cold low temperature, most liquid accelerators will also have problems such as segregation, stratification and crystallization, which will seriously affect their use effect; in the water-rich section of the broken surrounding rock tunnel, the setting time of the liquid alkali-free accelerator cannot meet the on-site requirements. In addition, due to the complex composition of shotcrete, the uneven quality of accelerators, the poor construction environment in the tunnel, and the extensive on-site operation management, etc., the wet shotcrete still has the problem of high rebound rate of shotcrete, which not only affects the construction progress, but also greatly increases the construction cost.

[0003] To reduce the rebound rate of sprayed concrete, the prior art has made relevant research. For example, Chinese invention patent application CN113511860A discloses a method for reducing the rebound rate by introducing emulsified asphalt into the sprayed concrete, which realizes the control of the rebound rate of the sprayed concrete by high-speed stirring of the concrete containing emulsified asphalt; CN109437722A discloses a low-rebound high-early-strength wet-sprayed concrete, which realizes the control of the rebound rate of the sprayed concrete by introducing high-strength super-micro additive (micro-silica powder, etc.); CN111377638A discloses a liquid alkali-free accelerator for improving the cohesion of sprayed concrete, which reduces the rebound rate by introducing modified materials into the accelerator to improve the cohesion of the sprayed concrete; CN111320408A discloses a nano high-strength sprayed concrete reinforcing agent, which reduces the construction rebound rate of the sprayed concrete by introducing cellulose nanofiber, steel fiber and other functional materials. The above researches mostly control the rebound rate of the sprayed concrete from the single perspective of adding key functional materials, without considering the influence of the spraying process on the rebound rate during the construction of the sprayed concrete, and the technical approach is relatively single. CN114528820B discloses a sprayed concrete rebound suppression method based on whole-process control, which reduces the construction rebound rate of the sprayed concrete by specifying the key parameters such as the mix proportion of the wet-sprayed concrete, the key functional materials and the spraying process, but the spraying process involved is still the conventional process of using liquid accelerator for construction, which fails to reduce the influence of water in the liquid accelerator on the rebound rate of the sprayed concrete, resulting in unsatisfactory rebound suppression effect. In recent years, in order to completely solve the problem of high rebound rate of wet-sprayed concrete, Xie Yongjiang and Li Kang of the Iron and Steel Research Institute proposed a technical idea of using alkali-free powder accelerator for wet-sprayed concrete operation, but the existing wet-sprayed equipment can only realize the construction operation of liquid accelerator, and there is a technical bottleneck in the wet-sprayed operation of powder accelerator. SUMMARY

[0004] The utility model aims at solving at least the technical problem that the existing spraying system is difficult to realize the wet-sprayed operation based on the powder accelerator. To this end, the purpose of the utility model is to provide a concrete spraying system.

[0005] To solve the above technical problems, the utility model adopts the following technical scheme:

[0006] The concrete spraying system comprises a concrete pumping system, a powder accelerator adding system, an air compressor and a mixing system, wherein the concrete pumping system and the mixing system are connected through a pipeline, the powder accelerator adding system and the mixing system are connected through a pressure-resistant air pipe, and the air compressor and the mixing system are connected through a pressure-resistant air pipe.

[0007] The specific function of the concrete spraying system is that mixed concrete and powder accelerator are respectively transported to a mixing system through a concrete pumping system and a powder accelerator adding system, high-pressure air output by an air compressor is used to fully and uniformly mix the concrete and the powder accelerator, and then the mixture is sprayed to a tunnel face.

[0008] Further, the concrete pumping system is of a piston cylinder type, has a maximum delivery capacity of 8m3 / h to 40m3 / h, a storage hopper capacity of 200L to 400L, a delivery pipe diameter variable range of Φ125mm to Φ80mm, a pumping pressure of 83bar to 90bar, and allows a maximum aggregate particle size of 15mm.

[0009] Further, the powder accelerator adding system is composed of a powder accelerator storage tank, a powder accelerator metering device, a compressed air storage tank and a compressed air drying and filtering device, the powder accelerator storage tank is made of stainless steel, has a volume of 500L to 2000L and can withstand a maximum air pressure of not less than 0.8MPa, the powder accelerator metering device is made of cast iron, is internally provided with an anti-blocking scraper and a gear turntable, and has a maximum powder output of 500g / r to 1000g / r, the compressed air storage tank is made of stainless steel, has a volume of 60L to 100L and can withstand a maximum air pressure of not less than 1.2MPa, and the compressed air drying and filtering device has an air drying efficiency of not less than 99%, a dedusting rate of not less than 98% and a working efficiency of not less than 100L / min.

[0010] Further, the air compressor has a maximum output air volume of 13m3 to 16m3 / h.

[0011] Further, the mixing system is composed of a mixing cavity one, a mixing cavity two and a spray head, the mixing cavity one is made of stainless steel, has a pipe diameter of Φ90mm, a length of not more than 100mm, and a pipe wall provided with one air inlet pipe of Φ30mm in a 45° oblique direction along the pipe length, the mixing cavity two is made of stainless steel, has a pipe diameter of Φ90mm, a length of not more than 100mm, and a pipe wall symmetrically provided with two air inlet pipes of Φ30mm in a 30° oblique direction along the pipe length, and the spray head is made of cast iron and has a pipe diameter variable range of Φ90mm to Φ50mm.

[0012] Compared with the prior art, the utility model has the beneficial effects that:

[0013] The utility model breaks through the technical bottleneck that wet spraying concrete can only use liquid accelerator for a long time, realizes accurate metering and stable delivery of powder accelerator, achieves the technical effect that the powder accelerator and the concrete are rapidly, uniformly and fully mixed, can avoid the adverse effect of water in conventional liquid accelerator on the setting and hardening speed and bonding strength of sprayed concrete, and effectively controls the rebound rate of sprayed concrete. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only aim at the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor based on the provided drawings.

[0015] Figure 1 It is a schematic diagram of the concrete spraying system of the present application.

[0016] Among them, 1 is a concrete pumping system, 2 is a powder accelerator adding system, 3 is an air compressor, and 4 is a mixing system.

[0017] Figure 2 It is a schematic diagram of the powder accelerator adding system.

[0018] Among them, 1 is a powder accelerator storage tank, 2 is a powder accelerator metering device, 3 is a compressed air storage tank, and 4 is a compressed air drying and filtering device.

[0019] Figure 3 It is a schematic diagram of the mixing system.

[0020] Among them, 1 is a mixing chamber one, 2 is a mixing chamber two, and 3 is a spray head. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] Referring to Figure 1 A concrete spraying system comprises a concrete pumping system, a powder accelerator adding system, an air compressor and a mixing system, wherein the concrete pumping system and the mixing system are connected by a pipeline, the powder accelerator adding system and the mixing system are connected by a pressure-resistant air pipe, and the air compressor and the mixing system are connected by a pressure-resistant air pipe.

[0023] Referring to Figure 2 The powder accelerator adding system comprises a powder accelerator storage tank, a powder accelerator metering device, a compressed air storage tank and a compressed air drying and filtering device.

[0024] Referring to Figure 3 The mixing system comprises a mixing chamber one, a mixing chamber two and a spray head. EMBODIMENT

[0025] A concrete spraying system comprises the following:

[0026] The concrete pumping system adopts a piston cylinder type fine stone concrete pump, has a maximum conveying capacity of 35 m 3 / h, a storage hopper capacity of 300 L, a conveying pipe diameter of Φ120mm~Φ90mm variable diameter, a pumping pressure of 85bar, and allows a maximum aggregate particle size of 12mm.

[0027] (2) The powder accelerator storage tank is made of 302 stainless steel, has a volume of 600L, and can withstand a maximum air pressure of 1.2MPa; the powder accelerator metering device is made of nodular cast iron, and can measure a maximum powder output of 600g / r; the compressed air storage tank is made of 302 stainless steel, has a volume of 75L, and can withstand a maximum air pressure of 1.6MPa; the compressed air drying and filtering device is an industrial-grade impurity removal and filtration integrated machine, has an air drying efficiency of 99%, an impurity removal rate of 99%, and a working efficiency of 500L / min.

[0028] (3) The air compressor is a double-spiral air compressor equipped with a cold drying device, and has a maximum output air volume of 15 m 3 / h.

[0029] (4) The mixing chamber one is made of 302 stainless steel, has a pipe diameter of Φ90mm and a length of 50mm, and has a gas inlet pipe with a pipe diameter of Φ30mm and an inclined direction of 45° along the pipe length; the mixing chamber two is made of 302 stainless steel, has a pipe diameter of Φ90mm and a length of 50mm, and has two gas inlet pipes with a pipe diameter of Φ30mm and an inclined direction of 30° symmetrically arranged along the pipe length; the nozzle is made of nodular cast iron, has a pipe diameter of Φ90mm~Φ50mm variable diameter.

[0030] (5) The mixed C30 concrete with a mixing ratio as shown in Table 1 is conveyed to the mixing chamber one in the mixing system through the concrete pumping system, and one-way high-pressure air is introduced into the mixing chamber one to mix with the concrete; the mixing chamber one changes the state of the concrete in the pipeline from dense flow to dilute phase flow, providing conditions for the subsequent mixing of the concrete and the powder accelerator.

[0031] (6) The other way of high-pressure air is introduced into the compressed air storage tank in the powder accelerator adding system, then processed through the compressed air drying and filtering device, and then the powder accelerator metering device carries the powder accelerator with technical indicators as shown in Table 2 to the mixing chamber two in the mixing system, while the third way of high-pressure air is introduced into the mixing chamber two to fully mix the powder accelerator with the concrete; the mixing chamber two fully atomizes the powder accelerator for uniform mixing with the concrete treated by the mixing chamber one, and finally sprayed through the nozzle.

[0032] The construction effect of the sprayed concrete adopting the utility model is shown in Table 3:

[0033] As shown in Table 3, the compressive strength and construction rebound rate of the sprayed concrete adopting the utility model are obviously superior to the conventional sprayed concrete based on liquid accelerator on the market, and the utility model has significant technical economy.

[0034] Table 1: Concrete mixing ratio (kg / m 3 )

[0035] Code Cement Fly ash Fine aggregate Coarse aggregate Water Water reducing agent Example 1 400 50 850 900 160 3.5 Example 2 400 100 750 950 170 4.0 Example 3 450 100 800 850 185 4.5 Example 4 500 50 800 850 200 5.0

[0036] Table 2: Technical index of alkali-free powder accelerator

[0037] Code Fineness (45 μm residue) Alkali content Initial setting time Final setting time 1 d compressive strength 28 d compressive strength ratio Example 1 6.5% 0.27% 57s 2 min 13.2 MPa 110% Example 2 7.9% 0.23% 1 min 15 s 2 min 35 s 11.7 MPa 108% Example 3 8.8% 0.35% 1 min 30 s 2 min 50 s 14.6 MPa 112% Example 4 10.0% 0.41% 2 min 3 min 15 s 15.2 MPa 109%

[0038] Table 3: Construction effect of sprayed concrete

[0039]

[0040] The above examples are merely illustrative of the utility model and are not intended to limit the embodiments. Other different forms of changes or variations can be made by those skilled in the art on the basis of the above description. Here, all the examples do not need to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the utility model.

Claims

1. A concrete spraying system, comprising a concrete pumping system, a powder accelerator addition system, an air compressor, and a mixing system, wherein the concrete pumping system and the mixing system are connected by pipelines, the powder accelerator addition system and the mixing system are connected by pressure-resistant air pipes, and the air compressor and the mixing system are connected by pressure-resistant air pipes; characterized in that: the concrete... The structure type of the pumping system is piston cylinder type, and the maximum conveying capacity is 8 m 3 / h~40 m 3 / h, the storage hopper capacity is 200 L~400 L, the conveying pipe diameter variable range is Φ125 mm~Φ80 mm, the pumping pressure is 83 bar~90 bar, and the maximum aggregate particle size allowed is 15 mm; The powder accelerator adding system is composed of a powder accelerator storage tank, a powder accelerator metering device, a compressed air storage tank and a compressed air drying and filtering device. The powder accelerator storage tank is made of stainless steel, has a volume of 500L-2000L and can bear a maximum air pressure of not less than 0.8MPa; The powder accelerator metering device is made of cast iron, is internally provided with anti-blocking scraping rods and a gear turntable, and has a maximum powder output of 500g / r-1000g / r. The compressed air storage tank is made of stainless steel, has a volume of 60L-100L and can bear a maximum air pressure of not less than 1.2MPa; The maximum output air volume of the air compressor is 13m 3 ~ 16m 3 / h; The mixing system is composed of a mixing chamber one, a mixing chamber two and a spray head. The mixing chamber one is made of stainless steel, has a pipe diameter of Φ90mm, a length of not more than 100mm, and a pipe wall provided with one air inlet pipe of Φ30mm in a 45° oblique direction along the pipe length. The mixing chamber two is made of stainless steel, has a pipe diameter of Φ90mm, a length of not more than 100mm, and a pipe wall provided with two air inlet pipes of Φ30mm in a 30° oblique direction along the pipe length. The spray head is made of cast iron and has a pipe diameter variable in a range of Φ90mm-Φ50mm.

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