Ground surface pre-grouting reinforcement method and device for tunnel broken shallow-buried section

Abstract

The invention belongs to the technical field of tunnel engineering construction, and discloses an earth surface pre-grouting reinforcement method and device for a broken shallow buried section of a tunnel. The method comprises the following steps: S1, geological exploration and field preparation: carrying out detailed exploration on the earth surface by using a geological radar and drilling sampling means; according to the exploration result, a broken layer and a grouting area needing to be reinforced are determined; a construction site is cleaned, grouting equipment, a sensor and monitoring equipment are arranged, and normal operation of the equipment is ensured; s2, grouting holes are distributed before grouting, specifically, accurate control over the grouting process is achieved by arranging a uniform diffusion mechanism through the synergistic effect of a telescopic assembly and a reset assembly, the telescopic assembly adopts grouting pipe joints which are nested in a sliding mode, segmented grouting can be conducted according to requirements, and it is ensured that each section of grouting area can be uniformly reinforced; the flange ring and the rubber piston in the grouting pipe effectively control the flow of the grouting liquid, and the problem of non-uniform grouting is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel engineering construction, and in particular relates to a surface pre-grouting reinforcement method and device for a broken shallow buried section of a tunnel. Background Art

[0002] During tunnel construction, especially under complex geological conditions, broken shallow buried sections often become construction difficulties. The so-called broken shallow buried sections refer to areas where the tunnel is buried at a shallow depth and there are large broken or weak zones in the rock and soil layers. The soil stability in these areas is poor and prone to problems such as collapse and water seepage, which poses serious safety hazards to tunnel construction. In order to solve these problems and ensure the smooth progress of tunnel construction, surface pre-grouting reinforcement technology came into being and has been widely used in tunnel reinforcement and stabilization. The principle of surface pre-grouting reinforcement technology is to carry out grouting operations on the surface to allow the slurry to penetrate into the soil and rock layers of the broken shallow buried section, filling cracks and voids, thereby improving the overall strength and stability of the soil. This technology can effectively enhance the density of the soil, improve its anti-seepage ability, reduce settlement and displacement problems that may occur during construction, and provide strong guarantees for tunnel construction.

[0003] For example, the utility model with publication number CN112901208B discloses a comprehensive construction method for the shallow buried section of a metropolitan railway tunnel using the mining method. In view of the characteristics of the tunnel being shallow, the surrounding rock being broken and interlayered, and the surface water being relatively abundant, the tunnel excavation adopts a three-step temporary arch excavation method, which greatly guarantees the safety of the excavation footage. In addition, through the in-tunnel pipe shed support and the advance pre-grouting auxiliary excavation construction method, it truly achieves safe excavation, improves quality and efficiency, solves the hidden dangers of construction safety in the shallow buried section of the tunnel, and reduces the probability of collapse and roof-falling accidents in the tunnel. In addition, grouting points are arranged in a plum blossom shape with a spacing of 1 meter within the grouting range divided on the tunnel surface. The grouting pipe adopts a 42mm diameter steel flower pipe for grouting. After the grouting is completed, anti-seepage treatment is carried out to reduce the infiltration of surface water to ensure the safety of the construction process.

[0004] When the above device is used, the following problems may occur: 1. During the grouting process, the slurry is prone to backflow through the grouting pipe or borehole, requiring repeated sealing, which affects efficiency. Excessive grouting pressure can easily cause surface uplift or pipeline damage, while too little pressure leads to insufficient reinforcement effect. Existing devices lack a structure for dynamically adjusting pressure.

[0005] 2. Since the diffusion of slurry depends on the splitting effect, it is random and dispersed, resulting in blind areas of reinforcement or local over-density. It is difficult to achieve segmented control of open hole grouting. The slurry cannot be evenly diffused during long drilling. When the grouting holes are not arranged reasonably, weak areas of uneven reinforcement may be formed. It is necessary to rely on field tests to adjust parameters, which increases costs.

[0006] Therefore, a surface pre-grouting reinforcement method and device for a broken shallow buried section of a tunnel are proposed to solve the problems raised in the background technology. Summary of the Invention

[0007] In order to solve the problems raised in the above background technology, the present invention provides a surface pre-grouting reinforcement method and device for a broken shallow buried section of a tunnel.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a surface pre-grouting reinforcement method for a broken shallow buried section of a tunnel, the specific steps of the method comprising: S1, Geological Survey and Site Preparation: Conduct detailed surface surveys using geological radar and borehole sampling; Based on the survey results, determine the broken layer and the area that needs grouting reinforcement; Clean up the construction site, set up grouting equipment, sensors and monitoring equipment, and ensure the equipment is operating normally; S2, grouting hole layout before grouting: Determine the number, location, depth and angle of grouting holes based on geological exploration data; Use a drilling rig to drill grouting holes, ensuring that the hole position is accurate and consistent with the direction of the broken layer; Install grouting pipes in the grouting holes and connect the grouting pumps and pressure monitoring systems; S3, grouting fluid preparation and injection: Prepare appropriate grouting fluid according to soil type and reinforcement requirements; Start the grouting equipment and inject the grouting liquid hole by hole and layer by layer, controlling the injection pressure, flow rate and time to ensure uniform penetration of the grout; Use sensors to monitor the pressure, flow rate and soil reaction during the grouting process in real time and dynamically adjust the grouting parameters; S4, monitoring and adjustment after grouting: Use surface settlement meters and stress sensor equipment to monitor surface deformation and soil stability after grouting in real time; Evaluate the grouting effect based on monitoring data. If uneven reinforcement or areas with missed grouting are found, perform additional grouting and adjust grouting parameters. Conduct necessary quality inspections in the reinforced areas to ensure that the grouting achieves the expected reinforcement effect. S5, post-stability testing and construction summary: After the grouting is completed, a period of stability observation is carried out to detect surface settlement, displacement changes and soil strength; Conduct long-term monitoring of the reinforced area to ensure that the stability of the soil around the tunnel is not affected; Summarize the key issues in the construction process, improve the construction plan, and provide reference and optimization options for subsequent projects.

[0009] A surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel, comprising: The tunnel has a circular top design; A mounting frame, fixedly installed inside the tunnel, the mounting frame being adapted to the tunnel; A positioning rod is fixedly mounted on the top of the mounting frame and is fixedly connected to the inner wall of the tunnel; A plurality of auxiliary pipes are arranged between the mounting frame and the inner wall of the tunnel; A plurality of grouting pipes, arranged inside the auxiliary pipe and having the same number as the auxiliary pipe; a backflow prevention mechanism, arranged on the outer wall of the auxiliary pipe; A uniform diffusion mechanism is arranged inside the grouting pipe; Among them, the uniform diffusion mechanism includes a telescopic component and a reset component. The telescopic component is composed of several grouting pipe sections with sliding and nested fittings and decreasing diameters, which are used to achieve segmented grouting; the interior of the grouting pipe in each group of grouting areas is respectively provided with two flange rings and a rubber piston, and the rubber piston is located in the middle of the two flange rings.

[0010] Preferably, the reset assembly comprises a mounting plate fixedly mounted on one end of the grouting pipe with the smallest diameter, and the diameter of the mounting plate is larger than the outer diameter of the largest grouting pipe.

[0011] Preferably, a mounting ring is provided on the fixed sleeve on the outer wall of the grouting pipe with the largest diameter, and two connecting ropes are provided on one side of the mounting plate. Both connecting ropes pass through the mounting ring and are slidably connected to the mounting ring.

[0012] Preferably, two flower grooves are respectively provided on the outer wall of the grouting pipe in each grouting area, and each of the flower grooves is designed in a plum blossom shape.

[0013] Preferably, the backflow prevention mechanism includes a plurality of backflow prevention components and a plurality of positioning components, and the positioning components are respectively arranged in the middle of two adjacent backflow prevention components.

[0014] Preferably, the backflow prevention component comprises two fixing rings fixedly sleeved on the outer wall of the auxiliary pipe, and a protective ring is respectively provided on one side of the two fixing rings close to each other.

[0015] Preferably, the ends of the two protective rings close to each other are irregularly designed, and in an initial state, the two protective rings are adapted to each other, that is, the outer ends of the two protective rings are completely fitted together.

[0016] Preferably, a plurality of elastic ropes are fixedly installed on the side where the two fixing rings are close to each other, and the plurality of elastic ropes are designed to be distributed in circles with equal distances around the axis of the auxiliary tube as the center, and the plurality of elastic ropes respectively pass through the two protective rings.

[0017] Preferably, the positioning assembly includes a positioning frame fixedly mounted on the outer walls of two adjacent fixing rings, the positioning frame is triangular in design and has slots formed on the outer wall.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention realizes precise control of the grouting process by setting a uniform diffusion mechanism through the coordinated action of the telescopic component and the reset component. The telescopic component adopts a sliding and nested grouting pipe section, which can perform segmented grouting according to demand to ensure that each grouting area can be evenly reinforced; the flange ring and rubber piston in the grouting pipe effectively control the flow rate of the grouting liquid, avoiding the problem of uneven grouting. At the same time, the plum blossom-shaped flower groove not only enhances the structural strength of the grouting pipe, but also improves the flow efficiency of the fluid, further optimizing the grouting effect.

[0019] The present invention achieves precise control of slurry backflow by setting up an anti-backflow mechanism and clever cooperation between the fixed ring and the protective ring. In the initial state, the outer end of the protective ring is completely fitted to form an effective seal; during grouting, the slurry pressure causes the protective ring to automatically open to ensure smooth outflow of the slurry; after the grouting is completed, the elastic rope returns to its original state, driving the protective ring to close again, forming a self-recovering seal. This design not only effectively prevents slurry backflow, but also enhances the adaptability of the component and improves its reliability in complex working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 Schematic diagram of the local cross-sectional structure of the tunnel of the present invention; Figure 3 For the present invention Figure 2 Schematic diagram of the enlarged structure of A in the middle; Figure 4 This is a schematic diagram of the combined structure of the backflow prevention mechanism and the uniform diffusion mechanism of the present invention; Figure 5 Schematic diagram of the explosion structure of the anti-backflow mechanism and the uniform diffusion mechanism of the present invention; Figure 6 For the present invention Figure 5 Schematic diagram of the enlarged structure of B; Figure 7 Schematic diagram of the cross-sectional structure of the backflow prevention mechanism and the uniform diffusion mechanism of the present invention; Figure 8 For the present invention Figure 7 Schematic diagram of the enlarged structure of C in the middle; Figure 9 Schematic diagram of the explosion structure of the backflow prevention assembly of the present invention; Figure 10It is a schematic diagram of the cross-sectional structure of the protection ring of the present invention.

[0021] In the figure: 1. Tunnel; 11. Mounting frame; 12. Positioning rod; 2. Auxiliary pipe; 21. Fixing ring; 211. Protective ring; 22. Elastic rope; 23. Positioning frame; 24. Circular groove; 3. Grouting pipe; 31. Flower trough; 32. Rubber piston; 33. Flange ring; 34. Mounting plate; 35. Mounting ring; 36. Connecting rope. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] like Figures 1 to 10 As shown, the present invention provides a surface pre-grouting reinforcement method for a broken shallow buried section of a tunnel, the specific steps of the method include: S1, Geological Survey and Site Preparation: Conduct detailed surface surveys using geological radar and borehole sampling; Based on the survey results, determine the broken layer and the area that needs grouting reinforcement; Clean up the construction site, set up grouting equipment, sensors and monitoring equipment, and ensure the equipment is operating normally; S2, grouting hole layout before grouting: Determine the number, location, depth and angle of grouting holes based on geological exploration data; Use a drilling rig to drill grouting holes, ensuring that the hole position is accurate and consistent with the direction of the broken layer; Install grouting pipes in the grouting holes and connect the grouting pumps and pressure monitoring systems; S3, grouting fluid preparation and injection: Prepare appropriate grouting fluid (such as cement slurry, chemical slurry, etc.) according to soil type and reinforcement requirements; Start the grouting equipment and inject the grouting liquid hole by hole and layer by layer, controlling the injection pressure, flow rate and time to ensure uniform penetration of the grout; Use sensors to monitor the pressure, flow rate and soil reaction during the grouting process in real time and dynamically adjust the grouting parameters; S4, monitoring and adjustment after grouting: Use surface settlement meters and stress sensor equipment to monitor surface deformation and soil stability after grouting in real time; Evaluate the grouting effect based on monitoring data. If uneven reinforcement or areas with missed grouting are found, perform additional grouting and adjust grouting parameters. Conduct necessary quality inspections in the reinforced areas to ensure that the grouting achieves the expected reinforcement effect. S5, post-stability testing and construction summary: After the grouting is completed, a period of stability observation is carried out to detect surface settlement, displacement changes and soil strength; Conduct long-term monitoring of the reinforced area to ensure that the stability of the soil around the tunnel is not affected; Summarize key issues in the construction process, improve construction plans, and provide reference for subsequent projects.

[0024] like Figures 1 to 10 As shown, a surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel comprises: a tunnel 1, the top of which is designed in an arc shape; a mounting frame 11, fixedly mounted inside the tunnel 1, the mounting frame 11 being adapted to the tunnel 1; a positioning rod 12, fixedly mounted on the top of the mounting frame 11 and fixedly connected to the inner wall of the tunnel 1; a plurality of auxiliary pipes 2, arranged between the mounting frame 11 and the inner wall of the tunnel 1; a plurality of grouting pipes 3, arranged inside the auxiliary pipes 2 and having the same number as the auxiliary pipes 2; a backflow prevention mechanism, arranged on the outer wall of the auxiliary pipe 2; and a uniform diffusion mechanism, arranged inside the grouting pipes 3. Among them, the uniform diffusion mechanism includes a telescopic component and a reset component. The telescopic component is composed of three sections of grouting pipes that are slidably nested and have decreasing diameters, which are used to realize segmented grouting; two flange rings 33 and a rubber piston 32 are respectively provided inside the grouting pipe 3 of each group of grouting areas, and the rubber piston 32 is located in the middle of the two flange rings 33; the reset component includes a mounting plate 34 fixedly mounted on one end of the grouting pipe 3 with the smallest diameter value, and the diameter value of the mounting plate 34 is greater than the outer diameter value of the largest grouting pipe 3; a mounting ring 35 is fixedly sleeved on the outer wall of the grouting pipe 3 with the largest diameter value, and two connecting ropes 36 are provided on one side of the mounting plate 34, and the two connecting ropes 36 both pass through the mounting ring 35 and are slidably connected to the mounting ring 35; two flower grooves 31 are respectively provided on the outer wall of the grouting pipe 3 on each grouting area, and each flower groove 31 is designed in a plum blossom shape.

[0025] The above solution is adopted: the mounting frame 11 is fixed inside the tunnel 1, which ensures that the entire reinforcement device can work stably and accurately in the tunnel 1. The positioning rod 12 is a key component connecting the mounting frame 11 and the inner wall of the tunnel 1, which can ensure the precise position of the grouting device in the tunnel 1, avoiding uneven reinforcement effect caused by improper equipment position, and can be flexibly adjusted according to different grouting needs through the uniform diffusion mechanism; the telescopic component can be grouted in sections as needed through the sliding-fit grouting pipe 3 structure, ensuring that each grouting area can be uniformly and fully reinforced; the grouting pipe 3 of each grouting area is provided with a flange ring 33 and a rubber piston 32, which can better control the flow of the grouting liquid, avoiding Uneven grouting; the design of the mounting plate 34 and the mounting ring 35 in the reset assembly ensures that the reset operation of the grouting device can be carried out smoothly after the grouting process is completed; the design of the mounting plate 34 not only has a physical support function, but also can enable the device to be freely adjusted during operation through the sliding property of the connecting rope 36, ensuring that it can quickly restore to its original state after the grouting process is completed, avoiding equipment jamming; the flower groove 31 on the outer wall of the grouting pipe 3 in each grouting area is designed to be plum blossom-shaped, which not only enhances the structural strength of the grouting pipe 3, but also better realizes the uniform diffusion of the grouting liquid; the shape of the flower groove 31 contributes to the flow and diffusion of the liquid. At the same time, the plum blossom-shaped design also improves the flow efficiency of the fluid, further optimizing the grouting effect.

[0026] like Figures 9 and 10 As shown, the backflow prevention mechanism includes several backflow prevention components and several positioning components, and the positioning components are respectively arranged in the middle of two adjacent backflow prevention components; the backflow prevention component includes two fixing rings 21 fixedly mounted on the outer wall of the auxiliary tube 2, and a protective ring 211 is respectively provided on the side where the two fixing rings 21 are close to each other; the ends of the two protective rings 211 close to each other are irregularly designed, and in the initial state, the two protective rings 211 are adapted, that is, the outer ends of the two protective rings 211 are completely fitted; several elastic ropes 22 are fixedly installed on the side where the two fixing rings 21 are close to each other, and the several elastic ropes 22 are all designed to be equidistantly distributed around the circumference with the axis of the auxiliary tube 2 as the center, and the several elastic ropes 22 respectively pass through the two protective rings 211; the positioning component includes a positioning frame 23 fixedly mounted on the outer walls of the two adjacent fixing rings 21, and the positioning frame 23 is triangular in design and has slots on the outer wall.

[0027] The above solution is adopted: the anti-backflow component is fixedly mounted on the two fixing rings 21 on the outer wall of the auxiliary pipe 2, which can effectively prevent the slurry from flowing back during the grouting process; the protective rings 211 on both sides of the fixing ring 21 are designed irregularly, so that in the initial state, the outer ends of the protective rings 211 are completely fitted. This design ensures that the anti-backflow effect of the component is maximized when there is no external force intervention; the irregular design of the protective ring 211 can provide appropriate elastic deformation when needed, so as to better adapt to different working environments and pressure changes, and prevent unnecessary backflow or leakage. The elastic ropes 22 on the fixing rings 21 are installed in an equidistant circular distribution, ensuring that the elastic tension of the anti-backflow component is always within an appropriate range; when the anti-backflow component is subjected to external force, the elastic ropes 22 can provide flexible support and protection to prevent the deformation of the component from exceeding the set range. The elastic design not only enhances the adaptability of the anti-backflow component, but also improves its reliability in high-pressure working environments. The working principle and use process of the present invention: During the construction preparation phase, the construction workers will place the auxiliary pipe 2 between the tunnel 1 and the mounting frame 11 to ensure its accurate positioning. The positioning rod 12 is inserted into the hole slot of the positioning frame 23. With the support of the positioning rod 12, the auxiliary pipe 2 is firmly fixed between the tunnel 1 and the mounting frame 11. This fixing process ensures the stability of the auxiliary pipe 2 in the tunnel 1 during the grouting operation, and prevents it from shifting due to external forces or vibrations, thus ensuring the smooth progress of subsequent work. After the auxiliary pipe 2 is installed, the grouting pipe 3 is inserted into each auxiliary pipe 2 in turn. A pressure sensor is installed at the tail end of the grouting pipe 3. The pressure sensor is connected to the controller of the linear drive mechanism and has the function of monitoring and feedback of grouting pressure. When the grouting system is started and grouting begins, the pressure sensor will detect the pressure in the grouting pipe 3 in real time and feedback a signal to the controller when the pressure reaches the set value. After receiving the signal, the controller will instruct the linear drive mechanism to start, so that the retractable grouting pipe 3 will retract to the set distance to achieve precise grouting control. The grouting system is connected to the grouting pump and begins to deliver slurry through the grouting pipe 3 into the auxiliary pipe 2. After entering the grouting pipe 3, the slurry flows through the flower groove 31 inside the grouting pipe 3 and further into the gap of the auxiliary pipe 2. At this time, the circular groove 24 inside the auxiliary pipe 2 becomes the outlet for the slurry to be released. When the slurry passes through the circular groove 24, due to the internal pressure, the elastic rope 22 will deform, causing the protective ring 211 at the end to automatically open outward under the action of pressure. As the protective ring 211 opens, the slurry can smoothly flow out of the circular groove 24 and be injected into the formation. The protective ring 211 has the ability to self-recover; after the grouting process is completed, the elastic rope 22 will return to its original shape due to the disappearance of external pressure, so that the two protective rings 211 are reattached to each other to form a sealed state, preventing the slurry from flowing back into the grouting pipe 3, effectively avoiding potential damage to the grouting pipe 3 caused by the slurry backflow; It is crucial to ensure the smooth operation and stability of the grouting system, especially when encountering equipment failure; by setting up the connecting rope 36, the construction personnel can effectively deal with the situation where the grouting pipe 3 cannot be recovered normally due to sensor failure or other reasons. The connecting rope 36 serves as an emergency mechanism and plays a backup role; when the sensor or the grouting pipe 3 fails and the grouting pipe 3 cannot be recovered through the automatic control system, the construction personnel can manually operate and pull the connecting rope 36; one end of the connecting rope 36 is connected to the mounting plate 34, which is part of the entire grouting system and is located at the position of the grouting pipe 3; by pulling the connecting rope 36, the construction personnel can drive the mounting plate 34 and the topmost grouting pipe 3 to move to the recovery position.

[0028] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0029] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A surface pre-grouting reinforcement method for a broken shallow buried section of a tunnel, characterized in that: The specific steps of the method include: S1, Geological Survey and Site Preparation: Conduct detailed surface surveys using geological radar and borehole sampling; Based on the survey results, determine the broken layer and the area that needs grouting reinforcement; Clean up the construction site, set up grouting equipment, sensors and monitoring equipment, and ensure the equipment is operating normally; S2, grouting hole layout before grouting: Determine the number, location, depth and angle of grouting holes based on geological exploration data; Use a drilling rig to drill grouting holes, ensuring that the hole position is accurate and consistent with the direction of the broken layer; Install grouting pipes in the grouting holes and connect the grouting pumps and pressure monitoring systems; S3, grouting fluid preparation and injection: Prepare appropriate grouting fluid according to soil type and reinforcement requirements; Start the grouting equipment and inject the grouting liquid hole by hole and layer by layer, controlling the injection pressure, flow rate and time to ensure uniform penetration of the grout; Use sensors to monitor the pressure, flow rate and soil reaction during the grouting process in real time and dynamically adjust the grouting parameters; S4, monitoring and adjustment after grouting: Use surface settlement meters and stress sensor equipment to monitor surface deformation and soil stability after grouting in real time; Evaluate the grouting effect based on monitoring data. If uneven reinforcement or areas with missed grouting are found, perform additional grouting and adjust grouting parameters. Conduct necessary quality inspections in the reinforced areas to ensure that the grouting achieves the expected reinforcement effect. S5, later stability testing and construction summary: After the grouting is completed, a period of stability observation is carried out to detect surface settlement, displacement changes and soil strength; Conduct long-term monitoring of the reinforced area to ensure that the stability of the soil around the tunnel is not affected; Summarize key issues in the construction process, improve construction plans, and provide reference for subsequent projects.

2. A surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel, applied to the surface pre-grouting reinforcement method for a broken shallow buried section of a tunnel as claimed in claim 1, characterized in that: include; The tunnel (1) has an arc-shaped top; A mounting frame (11) is fixedly mounted inside the tunnel (1), and the mounting frame (11) is adapted to the tunnel (1); A positioning rod (12) is fixedly mounted on the top of the mounting frame (11) and is fixedly connected to the inner wall of the tunnel (1); A plurality of auxiliary pipes (2) are arranged between the mounting frame (11) and the inner wall of the tunnel (1); A plurality of grouting pipes (3), arranged inside the auxiliary pipe (2) and having the same number as the auxiliary pipe (2); A backflow prevention mechanism is provided on the outer wall of the auxiliary pipe (2); A uniform diffusion mechanism is arranged inside the grouting pipe (3); The uniform diffusion mechanism comprises a telescopic assembly and a reset assembly, wherein the telescopic assembly is composed of a plurality of grouting pipe (3) sections that are slidably nested and have successively decreasing diameters, and is used to achieve segmented grouting; two flange rings (33) and a rubber piston (32) are respectively provided inside the grouting pipe (3) of each grouting area, and the rubber piston (32) is located between the two flange rings (33).

3. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 2 is characterized in that: The reset assembly comprises a mounting plate (34) fixedly mounted on one end of the grouting pipe (3) with the smallest diameter, wherein the diameter of the mounting plate (34) is greater than the outer diameter of the largest grouting pipe (3).

4. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 3 is characterized by: A mounting ring (35) is fixedly mounted on the outer wall of the grouting pipe (3) with the largest diameter, and two connecting ropes (36) are arranged on one side of the mounting plate (34). Both connecting ropes (36) pass through the mounting ring (35) and are slidably connected to the mounting ring (35).

5. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 2 is characterized in that: Two flower grooves (31) are respectively provided on the outer wall of the grouting pipe (3) on each grouting area, and each of the flower grooves (31) is designed in a plum blossom shape.

6. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 2, characterized in that: The backflow prevention mechanism includes a plurality of backflow prevention components and a plurality of positioning components, and the positioning components are respectively arranged in the middle of two adjacent backflow prevention components.

7. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 6, characterized in that: The backflow prevention component package is fixedly mounted on two fixing rings (21) on the outer wall of the auxiliary pipe (2), and a protective ring (211) is respectively provided on one side of the two fixing rings (21) close to each other.

8. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 7, characterized in that: The ends of the two protective rings (211) that are close to each other are irregularly designed. In the initial state, the two protective rings (211) are adapted to each other, that is, the outer ends of the two protective rings (211) are completely fitted together.

9. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 7, characterized in that: A plurality of elastic ropes (22) are fixedly mounted on one side of the two fixing rings (21) close to each other. The plurality of elastic ropes (22) are designed to be distributed in a circle with equal distances around the axis of the auxiliary tube (2) as the center. The plurality of elastic ropes (22) respectively penetrate the two protective rings (211).

10. The surface pre-grouting reinforcement device for a broken shallow buried section of a tunnel according to claim 6, characterized in that: The positioning assembly comprises a positioning frame (23) fixedly mounted on the outer walls of two adjacent fixing rings (21); the positioning frame (23) is triangular in design and has slots formed on its outer wall.

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