A delivery system and method of supporting for tunnel shotcrete

Abstract

The application belongs to the technical field of tunnel jet support, and particularly relates to a conveying system and method for tunnel jet quick-setting concrete. The conveying system comprises a feeding port, a mixing pipeline and a concrete jet machine. The mixing pipeline comprises a first pipeline, a second pipeline and a third pipeline connected in sequence. A screw rod one is arranged in the first pipeline, the second pipeline and the third pipeline. The first pipeline is connected with the feeding port. The second pipeline is movably connected with the first pipeline and the third pipeline at two ends. The third pipeline is connected with the concrete jet machine. A buffer cavity perpendicular to the conveying direction is arranged on the second pipeline near the first pipeline. A stirring cavity perpendicular to the conveying direction is arranged on the second pipeline near the third pipeline. The opening direction of the buffer cavity and the stirring cavity is opposite to that of the second pipeline. A stirring assembly is arranged in the stirring cavity. The buffer cavity and the stirring cavity are used for realizing continuous conveying of materials, improving efficiency, preventing blockage and reducing cost.

Description

Technical Field

[0001] This invention belongs to the field of tunnel shotcrete support technology, specifically relating to a conveying system and method for tunnel shotcrete quick-setting concrete. Background Technology

[0002] In tunnel grouting projects, cement setting time plays a crucial role, directly impacting project quality, safety, and construction efficiency. The length of the setting time determines whether the grouting material can reach the expected strength within the appropriate timeframe, ensuring the stability and safety of the project.

[0003] Rapid-setting concrete shotcrete support is a core technology for temporary and initial support in underground geotechnical engineering projects such as mine roadways, railway and highway tunnels, urban foundation pit slopes, and water conservancy tunnels. It relies on quick-setting agents to achieve rapid setting and hardening of concrete in a short time, quickly sealing the surrounding rock and preventing the collapse and deformation of the soil and rock mass. It has the characteristics of fast construction, timely support, and strong adaptability, and is widely used in the field of geotechnical engineering support.

[0004] Currently, traditional quick-setting concrete spraying construction for support generally adopts a split process of "pre-mixed material + post-addition of quick-setting agent" or "centralized mixing + pipeline transportation + spraying", which has many inherent defects, such as extraction and solidification blockage, poor mixing uniformity leading to large fluctuations in support quality, and poor construction adaptability, making it difficult to meet the needs of high-precision, high-efficiency, and high-quality support construction.

[0005] Therefore, it is necessary to improve the existing TBM tunneling support quick-setting concrete delivery and support process to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a conveying system and method for tunnel shotcrete quick-setting concrete, which achieves continuous mixing and conveying of concrete materials through a buffer chamber and a mixing chamber, prevents quick-setting concrete from gelling and clogging, and improves efficiency.

[0007] To achieve the above objectives, the present invention provides a conveying system for tunnel shotcrete quick-setting concrete, including an inlet, a mixing pipeline, and a concrete spraying machine; the mixing pipeline includes a first pipeline, a second pipeline, and a third pipeline connected in sequence, and a screw rod passing through the first pipeline, the second pipeline, and the third pipeline is provided in the mixing pipeline; The first pipeline is connected to the feed inlet, and the two ends of the second pipeline are movably connected to the first pipeline and the third pipeline, respectively; the third pipeline is connected to the concrete spraying machine. The second pipeline has a buffer cavity perpendicular to the conveying direction on the side near the first pipeline, and a stirring cavity perpendicular to the conveying direction on the side near the third pipeline; the opening directions of the buffer cavity and the stirring cavity are opposite to those of the second pipeline, and the stirring cavity is equipped with a stirring assembly.

[0008] Furthermore, the outer wall of the second pipeline is provided with a transmission rack and a drive gear meshing with the transmission rack. The drive gear is connected to the output shaft of the servo output motor and is used to drive the second pipeline to rotate in order to control the direction of the buffer cavity and the stirring cavity.

[0009] Furthermore, the volume of the stirring chamber is larger than the volume of the buffer chamber; The diameter of the second pipeline is larger than that of the first pipeline, and the connection end of the second pipeline with the first and third pipelines is equipped with a sealed bearing.

[0010] Furthermore, the stirring assembly includes a stirring blade disposed within the stirring chamber. The stirring blade is fixedly connected to an external transmission magnetic block via an output shaft. An electromagnet is disposed below the transmission magnetic block and is connected to the top of the output shaft of a motor. The electromagnet is used to drive or disengage from the transmission magnetic block by switching the electromagnet on and off, thereby starting and stopping the stirring blade.

[0011] Furthermore, the feed inlet includes a first feed unit and a second feed unit. The first feed unit is connected to the end of the first pipeline and is used for feeding slag and water. The second feed unit is connected to the upper side wall of the first pipeline and is used for feeding geopolymer adhesive.

[0012] Furthermore, the second feeding unit includes several hoppers, each hopper being connected to the upper side wall of the first pipeline via a second conveying screw; a transmission gear set is provided between the hopper and the second conveying screw, the transmission gear set including several meshing transmission teeth, each transmission tooth being provided with an electromagnetic clutch between it and the input end of each second conveying screw, and each of the several electromagnetic clutches being connected to the controller via a relay.

[0013] Furthermore, each of the hoppers is equipped with a distance sensor corresponding to each hopper, and several distance sensors are connected to the controller to detect changes in the height of the material in the hopper, thereby controlling the material output speed.

[0014] The present invention also provides a method for conveying quick-setting concrete for tunnel spraying, using the aforementioned conveying system for quick-setting concrete for tunnel spraying, comprising: conveying concrete material from the inlet into a first pipeline, simultaneously starting a screw and a mixing assembly, and rotating a second pipeline so that the opening of the mixing chamber faces upward and the opening of the buffer chamber faces downward. The mixing assembly mixes the concrete material fed into the mixing chamber. After the mixture is completely mixed, the second pipeline is rotated so that the opening of the mixing chamber faces downward. Under the rotation of the screw, the concrete material is transported to the third pipeline and sprayed by the concrete spraying machine onto the part of the tunnel that needs to be supported. At the same time, the concrete material in the first pipeline continues to enter the buffer chamber. After the concrete material in the mixing chamber has been completely delivered, the second pipeline is rotated so that the opening of the mixing chamber faces upward, allowing the concrete material in the buffer chamber to enter the mixing chamber. At the same time, the rotation of the screw continuously feeds the concrete material in the first pipeline into the mixing chamber for the next round of mixing.

[0015] Furthermore, the concrete materials include slag, water, and geopolymer adhesive, wherein the geopolymer adhesive includes cement, alkaline catalyst, early strength agent, nano-silica, and surfactant; the alkaline catalyst is composed of building gypsum and fly ash; The slag and water are fed from the first feeding unit, and the geopolymer adhesive is fed from the second feeding unit.

[0016] The present invention also provides a method for conveying and supporting quick-setting concrete for tunnel spraying, comprising: spraying concrete material into the part to be supported in the tunnel using the conveying method, and after initial setting, continuously spraying to keep it moist for at least 7 days to form initial support on the tunnel rock surface.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. The conveying system for quick-setting concrete shotcrete in tunnels provided by the present invention, by adding a second pipeline including a buffer chamber and a mixing chamber, enables the screw to continuously convey materials into the second pipeline while it is always rotating, and can continue to convey materials even after subsequent mixing and spraying, thereby achieving the purpose of mixing and spraying materials at the same time, significantly improving the efficiency of conveying and support, and effectively preventing pipeline blockage.

[0018] 2. This invention, by incorporating gears on the outer wall of the second pipeline and setting sealed movable connections at both ends of the second pipeline, allows for adjustment of the opening directions of the buffer chamber and the mixing chamber by rotating the second pipeline, thereby controlling the mixing and spraying processes. By controlling the rotational speeds of the screw and the mixing shaft within the mixing chamber, the material mixing time can be effectively controlled. This facilitates easy adjustment of the mixing time between the geopolymer adhesive and slag or slag mixtures collected from different geological formations, demonstrating strong compatibility and meeting the application requirements of various geological conditions.

[0019] 3. The diameter of the second pipeline is larger than that of the first pipeline, thus ensuring the normal operation of the buffer cavity in the inverted state for material discharge and the discharge of the initial material mixed on the first pipeline.

[0020] 4. The present invention does not require an accelerator. It uses engineering waste soil mixed with cement and geological polymer adhesive to manufacture fluidized quick-setting concrete, which has a high resource utilization rate and greatly reduces the preparation cost of shotcrete. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the conveying device for shotcrete quick-setting concrete in tunnels, as described in an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the structure for conveying various materials of the geopolymer adhesive in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the stirring state on the second pipeline in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the material discharge state on the second pipeline in an embodiment of the present invention.

[0025] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Screw 1; 2-Conveying screw 2; 3-Mixing pipeline; 31-First pipeline; 32-Second pipeline; 33-Third pipeline; 321-Buffer chamber; 322-Mixing chamber; 323-Transmission rack; 324-Drive gear; 325-Servo output motor; 326-Fixed bracket; 327-Support frame; 3221-Mixing blade; 3222-Output shaft; 3223-Transmission magnetic block; 3224-Electromagnet; 4-Mixing machine; 51-Feeding motor 1; 6-Transmission gear set; 7-Electromagnetic clutch; 8-Hopper; 81-Distance sensor. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0027] The gypsum, secondary fly ash, sodium sulfate, alum, sodium silicate, FDN high-efficiency water-reducing agent, surfactant, nano silica and other raw materials used in the following examples are all common commercial industrial-grade raw materials on the market. Unless otherwise specified, the methods involved in the following examples are all conventional methods in the art.

[0028] Example 1 The present invention provides a conveying system for quick-setting concrete sprayed in tunnels, including an inlet, a mixing pipeline 3 and a concrete spraying machine; the mixing pipeline 3 includes a first pipeline 31, a second pipeline 32 and a third pipeline 33 connected in sequence, and a screw rod 1 passing through the first pipeline 31, the second pipeline 32 and the third pipeline 33 is provided in the mixing pipeline 3; The first pipe 31 is connected to the feed inlet, and the two ends of the second pipe 32 are movably connected to the first pipe 31 and the third pipe 33, respectively; the third pipe 33 is connected to the concrete spraying machine. The second pipeline 32 has a buffer cavity 321 perpendicular to the conveying direction on the side near the first pipeline 31, and a stirring cavity 322 perpendicular to the conveying direction on the side near the third pipeline 33; the opening directions of the buffer cavity 321 and the stirring cavity 322 are opposite to those of the second pipeline 32, and the stirring cavity 322 is equipped with a stirring assembly.

[0029] Specifically, the first pipe 31 and the third pipe 33 are both fixed to the frame of the TBM tunneling machine. One end of the second pipe 32 is fitted outside the outlet end of the first pipe 31, and a first sealed bearing is provided between the second pipe 32 and the first pipe 31. The other end of the second pipe 32 is fitted inside the inlet end of the third pipe 33, and a second sealed bearing is provided between the second pipe 32 and the third pipe 33 for mutual support.

[0030] A fixed bracket 326 is provided on the outer circumference of the second pipeline 32. A support bearing is provided between the fixed bracket 326 and the outer wall of the middle part of the second pipeline 32, so that the second pipeline 32 is supported on the fixed bracket 326, and both ends are respectively sealed and movablely connected to the other two pipeline sections.

[0031] The outer wall of the second pipeline 32 is provided with a transmission rack 323 and a drive gear 324 meshing with the transmission rack 323. The drive gear 324 is connected to the output shaft of the servo output motor 325 and is used to drive the second pipeline 32 to rotate, thereby controlling the direction of the buffer chamber 321 and the stirring chamber 322. The output motor 325 is fixedly supported by a support frame 327.

[0032] like Figure 3 and 4 The buffer chamber 321 and the stirring chamber 322 are offset by 180 degrees vertically. By rotating the second pipe 32, one of the two chambers in the buffer chamber 321 and the stirring chamber 322 can be upside down with its opening facing downwards, allowing the material to fall into the pipe. At this time, the other chamber is in an upright working state.

[0033] like Figure 4During operation, screw 1 does not stop rotating. When the mixing chamber 322 is inverted and discharging the mixed material, the buffer chamber 321 is in an upright state. The initial mixed material on the first pipeline 31 enters the buffer chamber 321, so that the mixed material will not mix with the initial mixed material on the first pipeline 31, thus achieving the purpose of continuous material conveying by screw 1.

[0034] Specifically, the volume of the stirring chamber 322 is greater than the volume of the buffer chamber 321, so that the amount of material entering the buffer chamber 321 during discharge is less than the volume of the stirring chamber 322. Therefore, during the stirring process, as the screw 1 continues to rotate and feed material, there is still remaining space in the stirring chamber 322 for material to enter and mix.

[0035] To prevent the buffer cavity 321 from discharging material in an inverted state, and to avoid blockage of the second pipeline caused by the discharge of the initial material mixed on the first pipeline 31, in this application, the diameter of the second pipeline 32 is larger than that of the first pipeline 31, so as to ensure normal operation of the buffer cavity 321 discharging material in an inverted state and the discharge of the initial material mixed on the first pipeline 31.

[0036] Furthermore, the stirring assembly includes a stirring blade 3221 disposed within the stirring chamber 322. The stirring blade 3221 is fixedly connected to an external transmission magnetic block 3223 via an output shaft 3222. An electromagnet 3224 is disposed below the transmission magnetic block 3223. The electromagnet 3224 is connected to the top of the output shaft of the motor and is used to drive or disengage from the transmission magnetic block 3223 by switching the electromagnet 3224 on and off, thereby realizing the start and stop of the stirring blade 3221.

[0037] Furthermore, the feed inlet includes a first feed unit and a second feed unit. The first feed unit is connected to the end of the first pipeline 31 and is used for feeding slag and water, such as... Figure 3 The mixer 4 is located in the middle; the second feeding unit is connected to the upper side wall of the first pipeline 31 and is used for feeding the geopolymer adhesive.

[0038] The second feeding unit includes several hoppers 8, each hopper 8 being connected to the upper side wall of the first pipeline 31 via a conveying screw 2. A transmission gear set 6 is provided between the hoppers 8 and the conveying screw 2, mounted on a bracket. The transmission gear set 6 includes several meshing transmission teeth, and each transmission tooth is connected to the input end of each conveying screw 2 via an electromagnetic clutch 7. Each of the electromagnetic clutches 7 is connected to a controller via a relay, and the relays corresponding to the multiple electromagnetic clutches are relay four, relay five, relay six, etc. The conveying screw 2 is driven by the same feeding motor 51, and a relay 3 is connected in series in the circuit of the feeding motor 51, with the relay 3 connected to the controller.

[0039] The controller controls the opening or closing of the relays corresponding to each electromagnetic clutch 7, thereby connecting or disconnecting each conveying screw 2 from the output end of the feeding motor 51, thus enabling the individual conveying of surfactants, alkaline catalysts and other geopolymer adhesives.

[0040] To control the conveying efficiency of surfactants, alkaline catalysts, and other geopolymer adhesives, in Example 1 of this application, each surfactant, alkaline catalyst, and other geopolymer adhesive is placed in a separate hopper 8. Each hopper 8 has a regular internal cavity, and multiple distance sensors 81, corresponding one-to-one with each hopper 8, are installed above it. These distance sensors are connected to a controller and are designated as distance sensor two, distance sensor three, distance sensor four, etc. The distance sensors above the hoppers 8 are used to detect changes in the height of the material within the hoppers. Since the hoppers have regular internal cavities, such as a cylindrical or inverted conical cavity, changes in the height of the material within the hoppers 8 can be converted into changes in volume. By controlling the opening or closing of the corresponding conveying screw two 2 of each hopper 8, the volume change of the material within the hopper 8 is controlled, thereby controlling the material output speed.

[0041] Example 2 A method for conveying quick-setting concrete for tunnel spraying, using the aforementioned conveying system for quick-setting concrete for tunnel spraying, includes: conveying concrete material from the inlet into the first pipeline 31, simultaneously starting the screw 1 and the mixing assembly, and rotating the second pipeline 32 so that the opening of the mixing chamber 322 faces upward and the opening of the buffer chamber 321 faces downward. The mixing assembly mixes the concrete material fed into the mixing chamber 322. After the mixture is completely mixed, the second pipeline 32 is rotated so that the opening of the mixing chamber 322 faces downward. Under the rotation of the screw 1, the concrete material is transported to the third pipeline 33 and sprayed into the tunnel to be supported by the concrete spraying machine. At the same time, the concrete material in the first pipeline 31 continues to enter the buffer chamber 321. After the concrete material in the mixing chamber 322 has been completely transported, the second pipeline 32 is rotated so that the opening of the mixing chamber 322 faces upward, and the concrete material in the buffer chamber 321 enters the mixing chamber 322. At the same time, the rotation of the screw 1 continuously feeds the concrete material in the first pipeline 31 into the mixing chamber 322 for the next round of mixing.

[0042] Through the above scheme, the present invention enables the screw 1 to always be in a rotating state to convey materials into the second pipeline 32, and to continue conveying materials even after subsequent mixing and spraying, thereby achieving the purpose of mixing and spraying materials at the same time, significantly improving the conveying and support efficiency, and effectively preventing pipeline blockage.

[0043] The concrete materials include slag, water, and geopolymer adhesive, wherein the geopolymer adhesive includes cement, alkaline catalyst, early strength agent, nano-silica, and surfactant; the alkaline catalyst is composed of building gypsum and fly ash. The slag and water are fed from the first feeding unit, and the geopolymer adhesive is fed from the second feeding unit.

[0044] Specifically, the geopolymer adhesive contains a surfactant and an alkaline catalyst in a mass ratio of 2.5-7.5:20-30.

[0045] The alkaline catalyst is composed of building gypsum and secondary fly ash in a 1:3 ratio. The surfactant mass percentages are: sodium sulfate: 10%–35%, alum: 40%–50%, sodium silicate: 10%–20%, FDN high-efficiency water-reducing agent: 10%–25%, and the sum of the surfactant weight percentages is 100%.

[0046] Geopolymer adhesives also include geopolymer adhesive early strength agents and nano silica, with the mass ratio of early strength agent: nano silica: surfactant: alkaline catalyst being 2.5-3.5: 5-20: 2.5-7.5: 20-30.

[0047] Among them, the early strength agent is Kaiyan brand inorganic early strength agent. The specific surface area of ​​nano-silica is 640±50m². 2 / g, particle size 1nm~100nm, surface hydroxyl mass fraction 20%~50%, SiO 2-x The quality fraction is greater than 99.9%.

[0048] The excavated soil is slag or a mixture of slag, or engineering excavated soil containing a mixture of SiO2 and Al2O3 obtained during the tunneling process of a TBM (Tunnel Boring Machine). The excavated soil is widely available and inexpensive. The cement is P·O 42.5 grade ordinary Portland cement.

[0049] The mass percentage of slag or slag mixture: early strength agent: nano silica: surfactant: alkaline catalyst is 8.75-400: 2.5-3.5: 5-20: 2.5-7.5: 20-30.

[0050] In some specific implementations, the final material ratio is as follows: every two kilograms of Shenzhen slag contains the following mass ratio of cement: alkaline catalyst: surfactant: early strength agent: nano silica: water in the mass ratio of 500g: 150g: 7.5g: 30g: 125g: 987g.

[0051] Before feeding materials, the SiO2 and Al2O3 components in the engineering waste soil are tested. The engineering waste soil can be drilled multiple times along the tunnel line to test the SiO2 and Al2O3 content. The SiO2 and Al2O3 content of engineering waste soil in tunnel excavation in different areas is different, and the amount of geopolymer adhesive and cement used is also different.

[0052] For example: Construction waste soil: excavated soil from the Phase IV project of Shenzhen Metro Line 3, is brownish-red and yellowish-brown, mainly in a hard plastic state, with a rough cut surface, containing about 10-30% sand and gravel, locally containing a large number of weathered particles, mainly composed of quartz, uneven in hardness, locally containing plastic particles, and is residual granite soil, with a dry density of 1.273 kg / m³. 3 The moisture content is 8%.

[0053] Water: Mixing water: Tap water, surface water and groundwater can be used for mixing solidified soil. The mass concentration of chloride ions should not exceed 600 mg / L. There should be no obvious grease or foam, and no obvious color or odor. Tap water can be used as mixing water.

[0054] The TBM (Tunnel Boring Machine) weighs the corresponding mass ratio of slag, cement, and geopolymer adhesive using a weighbridge. Water is pumped out via the TBM's water tank and metering pump. Simultaneously, conveying screw 1 is activated, and the TBM's mixer 4 transports the water and slag through the inlet section of the first pipeline 31 for mixing. Conveying screws 2 for surfactants, alkaline catalysts, and other geopolymer adhesives intermittently open and close, delivering the corresponding mass of material to the channel where conveying screw 1 is located for mixing. Within a set time, the mixture is conveyed to the mixing chamber 322 and continuously mixed at a rate of 40 r / min for 2-5 minutes to form premixed fluidized quick-setting concrete. The concrete is then discharged to a rotor-type concrete spraying machine for spraying.

[0055] The rotation of the second pipeline 32 is based on a preset time. By intermittently controlling the switching between the buffer chamber 321 and the stirring chamber 322 on the second pipeline 32, the material is conveyed.

[0056] In this embodiment, a single feeding motor 51 drives several conveying screws 2 to rotate. A distance sensor detects changes in material volume, and the amount of material discharged from the hopper 8 is calculated based on these changes. Electromagnetic clutches 7 are installed between the feeding motor 51 and each of the conveying screws 2. A controller uses several relays to control the opening and closing of these electromagnetic clutches 7, thereby controlling the operation of the conveying screws 2 and ultimately controlling the conveying capacity of each hopper 8. The overall structure is simple and easy to use.

[0057] Example 3 A method for conveying and supporting quick-setting concrete in tunnels includes: spraying concrete material into the tunnel to be supported using the conveying method, and after initial setting, continuously spraying to keep it moist for at least 7 days to form initial support on the tunnel rock surface.

[0058] In summary, this invention overcomes the shortcomings of existing technologies that require all materials to be introduced into a mixing container before uniform mixing, achieving the feature of simultaneous mixing and material conveying. The overall structure is simple, easy to use, and does not require a large mixing container. At the same time, by controlling the rotation speed of the screw 1 and the mixing shaft in the mixing chamber 322 respectively, the mixing time of the materials can be effectively controlled, making it convenient to adjust the mixing time of the geological polymer adhesive with slag or slag mixtures collected from different geological sites at any time. It has strong compatibility and meets the usage requirements of different geological sites.

[0059] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A conveying system for shotcrete quick-setting concrete in tunnels, characterized in that, It includes a feed inlet, a mixing pipeline (3) and a concrete spraying machine; the mixing pipeline (3) includes a first pipeline (31), a second pipeline (32) and a third pipeline (33) connected in sequence, and a screw rod (1) is provided in the mixing pipeline (3) through the first pipeline (31), the second pipeline (32) and the third pipeline (33); The first pipe (31) is connected to the feed inlet, and the two ends of the second pipe (32) are movably connected to the first pipe (31) and the third pipe (33) respectively; the third pipe (33) is connected to the concrete spraying machine; The second pipeline (32) has a buffer cavity (321) perpendicular to the conveying direction on the side near the first pipeline (31), and a stirring cavity (322) perpendicular to the conveying direction on the side near the third pipeline (33); the opening directions of the buffer cavity (321) and the stirring cavity (322) are opposite to those of the second pipeline (32), and the stirring cavity (322) is equipped with a stirring assembly.

2. The tunnel shotcrete quick-setting concrete conveying system according to claim 1, characterized in that, The outer wall of the second pipeline (32) is provided with a transmission rack (323) and a drive gear (324) meshing with the transmission rack (323). The drive gear (324) is connected to the output shaft of the servo output motor (325) and is used to drive the second pipeline (32) to rotate in order to control the direction of the buffer cavity (321) and the stirring cavity (322).

3. The tunnel shotcrete quick-setting concrete conveying system according to claim 1, characterized in that, The volume of the stirring chamber (322) is greater than the volume of the buffer chamber (321); The diameter of the second pipe (32) is larger than that of the first pipe (31), and the connection end of the second pipe (32) with the first pipe (31) and the third pipe (33) is provided with a sealed bearing.

4. The tunnel shotcrete quick-setting concrete conveying system according to claim 1, characterized in that, The stirring assembly includes a stirring blade (3221) disposed in the stirring chamber (322). The stirring blade (3221) is fixedly connected to an external transmission magnetic block (3223) via an output shaft (3222). An electromagnet (3224) is provided below the transmission magnetic block (3223). The electromagnet (3224) is connected to the top of the output shaft of the motor and is used to drive or disengage from the transmission magnetic block (3223) by switching the electromagnet (3224) on and off, thereby realizing the start and stop of the stirring blade (3221).

5. The tunnel shotcrete quick-setting concrete conveying system according to claim 1, characterized in that, The feed inlet includes a first feed unit and a second feed unit. The first feed unit is connected to the end of the first pipeline (31) and is used for feeding slag and water. The second feed unit is connected to the upper side wall of the first pipeline (31) and is used for feeding geopolymer adhesive.

6. The tunnel shotcrete quick-setting concrete conveying system according to claim 5, characterized in that, The second feeding unit includes several hoppers (8), each hopper (8) is connected to the upper side wall of the first pipeline (31) through a second conveying screw (2); a transmission gear set (6) is provided between the hopper (8) and the second conveying screw (2), the transmission gear set (6) includes several meshing transmission teeth, and an electromagnetic clutch (7) is provided between each transmission tooth and the input end of each second conveying screw (2), and each of the several electromagnetic clutches (7) is connected to the controller through a relay.

7. The tunnel shotcrete quick-setting concrete conveying system according to claim 6, characterized in that, Above each of the hoppers (8) is a distance sensor (81) corresponding to each hopper (8). Several distance sensors (81) are connected to the controller to detect the height change of the material in the hopper (8) and thus control the material output speed.

8. A method for conveying quick-setting concrete for tunnel spraying, characterized in that, The conveying system for tunnel shotcrete quick-setting concrete according to any one of claims 1-7 includes: conveying concrete material from the inlet into the first pipeline (31), simultaneously starting the screw (1) and the mixing assembly, and rotating the second pipeline (32) so that the opening of the mixing chamber (322) faces upward and the opening of the buffer chamber (321) faces downward. The mixing assembly mixes the concrete material fed into the mixing chamber (322). After the mixture is completely mixed, the second pipeline (32) is rotated so that the opening of the mixing chamber (322) faces downward. Under the rotation of the screw (1), the concrete material is transported to the third pipeline (33) and sprayed by the concrete spraying machine to the part to be supported in the tunnel. At the same time, the concrete material in the first pipeline (31) continues to enter the buffer chamber (321). After the concrete material in the mixing chamber (322) is completely transported, the second pipeline (32) is rotated so that the opening of the mixing chamber (322) faces upward, and the concrete material in the buffer chamber (321) enters the mixing chamber (322). At the same time, the rotation of the screw (1) continuously feeds the concrete material in the first pipeline (31) into the mixing chamber (322) for the next round of mixing.

9. The method for conveying quick-setting concrete for tunnel spraying according to claim 8, characterized in that, The concrete materials include slag, water, and geopolymer adhesive, wherein the geopolymer adhesive includes cement, alkaline catalyst, early strength agent, nano-silica, and surfactant; the alkaline catalyst is composed of building gypsum and fly ash. The slag and water are fed from the first feeding unit, and the geopolymer adhesive is fed from the second feeding unit.

10. A method for conveying and supporting quick-setting concrete in tunnels, characterized in that, include: The concrete material is sprayed into the tunnel to be supported using the conveying method described in claim 8 or 9. After initial setting, it is continuously sprayed to keep it moist for at least 7 days to form initial support on the tunnel rock surface.

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