Construction method of magnetic slurry grouting with pipe roof and advanced small pipe

Abstract

The present invention provides a construction method for grouting magnetic slurry in pipe roofs and advanced small conduits. The improvement includes placing magnetic flower tubes in grouting holes and steel pipes during grouting of advanced curtains, pipe roofs, and advanced small conduits, and connecting them to an external power source to control the magnetic field strength. Water-based epoxy resin, a curing agent, magnetic powder, and other materials are then added to the cement slurry and stirred evenly to prepare magnetic cement slurry. Grouting operations are then performed on the advanced curtain grouting holes, pipe roofs, and advanced small conduits. This improved magnetic cement slurry can evenly diffuse the grouting liquid in the voids or cracks of the surrounding rock, effectively reducing the diffusion range, preventing slurry leakage and slurry runaway, and rapidly filling the interior of the steel pipe. Gas in the grouting pipe can be better discharged, so that the injected magnetic cement slurry can bond with the surrounding rock within the effective range to form a more stable concrete consolidation body, thereby better increasing the stability of the surrounding rock, while also providing better waterproofing and ensuring the safety of tunnel construction.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a construction method for performing magnetic slurry grouting using a pipe roof and an advanced small guide tube. Background Art

[0002] Nowadays, tunneling has been increasingly used in underground construction. As the number and scale of tunneling projects gradually expand, the problems faced are becoming increasingly complex and the construction difficulty is increasing. Therefore, it is necessary to adopt advanced tunneling technology to ensure construction quality.

[0003] The advanced curtain grouting technology is to drill holes along the excavation contour line and the excavation working surface at a certain spacing, diameter, depth, and inclination angle, and inject cement mortar into the holes, so that the cement slurry forms a certain water-proof curtain and reinforcement ring within a certain range outside the excavation contour line, thereby penetrating the strong water-rich or broken surrounding rock layer.

[0004] At present, the widely used ordinary cement grouting cannot diffuse the slurry into all rock cracks and other channels within the grouting curtain range only by the grouting pressure and the fluidity of cement. In addition, when grouting the pipe roof and the advance small guide tube, the cement slurry filling density in the steel pipe is not enough, the slurry adsorbed around the pipe body is easily dispersed by water, the grouting liquid diffuses unevenly in the voids or cracks of the surrounding rock, and the diffusion range is large, so that it cannot achieve the purpose of very good waterproofing, water control and effective reinforcement of the surrounding rock. Therefore, there is an urgent need to develop magnetic cement grouting. Summary of the Invention

[0005] In order to overcome the technical problem that the protection method of tunnel construction in the existing technology cannot be effectively applied to geological conditions with poor surrounding rock stability or the presence of groundwater, the technical problem to be solved by the present invention is to improve the grouting of pipe roofs and advance small conduits, and provide a construction method for magnetic slurry grouting of pipe roofs and advance small conduits. This construction method can increase the fluidity of the grouting liquid, so that the grouting liquid can quickly fill the inside of the steel pipe and can better discharge the gas in the grouting pipe; the magnetic slurry diffuses to the surrounding areas through the slurry holes, and due to the effect of the magnetic field, it can effectively reduce the filling radius, avoid slurry running and leakage, and make it more effective to fill the cracks or gaps in the surrounding rock, thereby making the surrounding rock of the tunnel excavation surface have stronger stability, and at the same time can be more effectively waterproof, ensuring the safety of tunnel construction.

[0006] In order to achieve the above technical features, the purpose of the present invention is achieved as follows: a construction method for magnetic slurry grouting of a pipe roof and an advanced small pipe:

[0007] Through curtain grouting, the surrounding rock of the fault fracture zone within a range of at least 5m outside the excavation outline is solidified to prevent collapse and sudden surge. At the same time, the advance pipe shed and advance small guide pipe are set up to enhance the strength and stability of the advance support. The specific steps include:

[0008] S1, advanced geological forecast:

[0009] Detect the location of the fault fracture zone and groundwater in front of the tunnel face, and detect the development of karst;

[0010] S2, measurement and setting out:

[0011] Determine the forming position of the curtain layer, thereby determining the drilling position of the grouting holes, and mark the drilling positions. The distance between adjacent grouting holes is equal;

[0012] S3, pouring grout stop wall:

[0013] Determine the length of the concrete stop wall according to the faults on the tunnel face and the water discharge conditions, and cast the stop wall;

[0014] S4, buried pipe:

[0015] Drill to the required depth at the marked drilling location, bury the orifice pipe, and continue drilling along the orifice pipe to the designed depth;

[0016] S5, place the magnetic flower tube in the drill hole:

[0017] A magnetic flower tube is placed in the grouting hole, and the energized wire is connected to an external controllable switch power supply, and the magnetic field size of the magnetic flower tube is adjusted by the external controllable switch power supply;

[0018] S6, preparing magnetic slurry:

[0019] S7, Grouting:

[0020] Grouting is carried out through the grouting pipe into the grouting holes. The grouting order is first the outer ring holes, then the bottom holes, and then the middle holes after sealing. Grouting is carried out from bottom to top. Grouting is carried out at intervals in each ring of drilled holes. A combination of forward segmented grouting and backward segmented grouting is adopted.

[0021] S8, after the advanced curtain grouting is completed, the arch formwork is set up at the hole entrance, the guide pipe is embedded in advance, and then the concrete is poured;

[0022] S9, pipe roof installation:

[0023] Use the casing follow-up method to drill from high hole position to low hole position. The hole depth meets the design requirements and the pipe shed is installed.

[0024] S10, placing magnetic flower tubes in the tube shed:

[0025] A magnetic flower tube is placed in the tube shed, and the energized wire is connected to an external controllable switch power supply, and the magnetic field size of the magnetic flower tube is adjusted by the external controllable switch power supply;

[0026] S11, preparing magnetic slurry:

[0027] S12, pipe roof grouting:

[0028] Grouting magnetic slurry into the pipe roof through the grouting pipe should follow the principle of: first two sides and then the middle, grouting in skip holes, and from thin to thick;

[0029] S13, arranging pre-drilling positions of the leading small guide tube, and performing a drilling operation at the pre-drilling positions to obtain pre-grouting holes;

[0030] S14, driving the advance small pipe into the pre-grouting hole and fixing the advance small pipe;

[0031] S15, place a magnetic flower tube in the small catheter ahead:

[0032] A magnetic flower tube is placed in the leading small conduit, and the energized wire is connected to an external controllable switch power supply, and the magnetic field size of the magnetic flower tube is adjusted by the external controllable switch power supply;

[0033] S16, preparing magnetic slurry:

[0034] S17, grouting operation is performed on the advance small guide tube through the grouting pipe to obtain pre-support before tunnel excavation.

[0035] The magnetic slurry in S6, S11 and S16 is prepared from water-based epoxy resin, curing agent, magnetic powder, cement, water, dispersant, defoamer and water reducer, with the specific proportions being: water-cement ratio 0.2-0.4, magnetic powder content 10%-30%, dispersant 5%, defoamer 2%, water reducer 1%, epoxy resin emulsion: curing agent = 1:0.85.

[0036] The magnetic flower tube is drilled with flower tube holes with a diameter of 10 to 16 mm, the hole spacing of the flower tube holes is 15 to 20 cm, and the flower tube holes are arranged in a plum blossom shape on the tube wall of the magnetic flower tube. The length of the tail of the magnetic flower tube without flower tube holes is at least 150 cm.

[0037] The pipe shed is set up within 150° of the arch, with a circumferential spacing of 20 to 30 cm, an external insertion angle of 1 to 3°, and an overlap length of not less than 1 m.

[0038] When grouting is performed inside the steel pipes of the pipe rack in S12, an exhaust pipe must be arranged and the final pressure value must reach at least 1.0 MPa and remain stable for at least 5 minutes.

[0039] The specific operations of S14 to S17 are:

[0040] The front end of the small leading pipe is processed into a pointed cone shape, and a slurry outlet hole is provided on the pipe wall according to the design requirements;

[0041] According to the requirements of the plum blossom design, the position of the small advance guide tube required for this cycle should be accurately set on the excavation surface;

[0042] Use a pneumatic drill to drill holes. The external insertion angle of the leading small conduit is strictly in accordance with the design requirements. The tail is welded to the steel frame. The leading small conduit is parallel to the center line of the line.

[0043] The small pipe is pushed forward by a special jacking head, and the length of the hole to be drilled should not be less than 90% of the pipe length. When the small pipe is pushed forward, the pipe mouth should be protected from damage and deformation so that it can be connected to the grouting pipeline.

[0044] Check whether the opening of the small advance conduit meets the sealing standard to prevent leakage;

[0045] The tail end of the leading small conduit is exposed for a sufficient length and welded to the steel support;

[0046] Grouting is carried out using a grouting machine. The magnetic slurry is prepared according to the design requirements. The grouting pressure is 0.5-1.0 MPa. The completion standard is that the required grouting volume is reached in a single pipe. After the grouting is completed, the pipe mouth is sealed.

[0047] In general, the above technical solution conceived by the present invention, compared with the prior art, provides a construction method for magnetic slurry grouting using a pipe roof and an advanced small pipe, which has the following beneficial effects:

[0048] 1. The present invention proposes for the first time to add magnetic material to cement grouting slurry. The magnetic material is added to the cement grouting slurry and used in conjunction with a magnetic grouting flower tube, so that the magnetic slurry is filled from the inside of the grouting tube to the surrounding area, effectively increasing the density of the cement slurry filled in the grouting hole.

[0049] 2. During the advanced curtain grouting, the present invention places a magnetic flower tube in the grouting hole and connects it to an external switching power supply. By controlling the size of the magnetic field, the magnetic slurry can be filled from the flower tube hole to the surrounding area, effectively increasing the density of the slurry in the grouting hole, and reducing the diffusion range of the grouting liquid in the rock formation gap, so that the consolidation circle formed on the outer circle of the curtain has better strength and durability, and avoids slurry waste.

[0050] 3. During grouting of the pipe roof, the present invention places a magnetic flower pipe in the pipe roof, which is connected to an external switching power supply to control the size of the magnetic field, so that the grouting liquid can quickly fill the inside of the steel pipe and better discharge the gas in the grouting pipe; and the magnetic slurry diffuses to the surrounding areas through the overflow holes around the pipe roof. When filling cracks or gaps in the surrounding rock, the filling radius can be effectively reduced to avoid slurry leakage, so that the injected magnetic cement slurry can bond with the soil within the effective range to form a more stable concrete consolidation body, thereby achieving better water-stopping and waterproofing effects.

[0051] 4. During grouting with the advance small conduit, the present invention places a magnetic flower tube in the advance small conduit, connects an external power supply, and controls the size of the magnetic magnetic field. The magnetic slurry can fill the advance small conduit more densely, and can better remove the gas in the tube, and can make the grouting liquid diffuse more evenly in the voids or cracks of the surrounding rock, thereby reducing its diffusion range and effectively preventing leakage and slurry running. The grouting liquid can better replace the positions occupied by moisture and air in soil particles and rock cracks in a filling manner, and bond with them to form a consolidated body with high strength and better waterproof performance, thereby better improving the overall strength of the rock mass itself and improving the surrounding rock support status.

[0052] 5. When grouting the pipe roof and the advance small guide tube, the magnetic field inside the pipe body has an attractive force, which can prevent the mortar adsorbed around the pipe body from being washed away by water seepage from the rock mass. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will be further described below with reference to the accompanying drawings and examples.

[0054] Figure 1 Magnetic mortar grouting process.

[0055] Figure 2 Schematic diagram of conventional advance curtain grouting.

[0056] Figure 3 This is a schematic diagram of the advanced curtain grouting of the present invention.

[0057] Figure 4 This is a schematic diagram of conventional advance small-duct grouting.

[0058] Figure 5 This is a schematic diagram of the advanced small-duct magnetic slurry grouting of the present invention.

[0059] Figure 6 This is a schematic diagram of the magnetic slurry grouting of the pipe roof of the present invention.

[0060] In the figure: 1. Grouting pipe; 2. Magnetic flower pipe; 3. Grouting hole; 4. Power conductor; 5. Advance small guide tube; 6. Pipe scaffold; 7. Grouting plug; 8. Reinforcement hoop; 9. Iron hoop; 10. Crack; 11. Consolidation body; 12. External switching power supply. DETAILED DESCRIPTION

[0061] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0062] Example 1:

[0063] In order to better highlight the advantages of the present invention, the present invention is further described below in conjunction with schematic diagrams of conventional grouting and magnetic slurry grouting.

[0064] See also Figure 2 、 4 , Figure 2 This is conventional advanced curtain grouting. During the grouting process, slurry enters the grouting hole 3 through the grouting pipe 1. A small amount of slurry is adsorbed around the grouting hole, and some slurry will flow along the rock cracks 10, resulting in slurry leakage. Figure 4 This is conventional advance small-tube grouting. During the grouting process, the slurry enters the advance small-tube 5 through the grouting pipe 1, and then diffuses to the surroundings through the overflow hole. A small amount of slurry is adsorbed around the steel pipe, slurry leaks into the rock cracks 10, and a consolidated body 11 is formed in the rock voids.

[0065] See also Figure 5-6 The present invention improves the magnetic slurry grouting of pipe roofs and advanced small guide tubes. It includes a strong electromagnetic flower pipe device. The strong electromagnetic flower pipe device is to add a magnetic flower pipe 2 in the steel flower pipe, and connect it to the external switching power supply 3 through a powered wire 4. The size of the magnetic field inside the steel flower pipe is controlled by adjusting the current of the external switching power supply 3. During grouting, the magnetic slurry absorbs a large amount of layered slurry around the magnetic flower pipe 2 under the action of magnetism, preventing slurry from running or leaking.

[0066] Example 2:

[0067] comparison Figure 1 、 3 5.6. Construction method of magnetic slurry grouting for pipe roof and advanced small pipe:

[0068] Through curtain grouting, the surrounding rock of the fault fracture zone within a range of at least 5m outside the excavation outline is solidified to prevent collapse and sudden surge. At the same time, the advance pipe shed and advance small guide pipe are set up to enhance the strength and stability of the advance support. The specific steps include:

[0069] S1, advanced geological prediction: detecting the location of the fault fracture zone and groundwater in front of the tunnel face, and detecting the development of karst;

[0070] S2, measurement and setting out: determine the forming position of the curtain layer, thereby determining the drilling position of the grouting holes 3, and mark the drilling positions, and ensure that the distance between two adjacent grouting holes 3 is equal;

[0071] S3, pouring grout stop wall: Determine the length of the concrete grout stop wall according to the fault of the tunnel face and the water discharge situation, and pour the grout stop wall;

[0072] S4, burying pipes: drill to the required depth at the marked drilling location, bury the orifice pipe, and continue drilling along the orifice pipe to the designed depth;

[0073] S5, placing a magnetic flower tube in the borehole: placing a magnetic flower tube 2 in the grouting hole 3, connecting the energized wire 4 to the external controllable switch power supply 12, and adjusting the magnetic field of the magnetic flower tube 2 by the external controllable switch power supply 12;

[0074] S6, preparing magnetic slurry:

[0075] S7, grouting: grouting is performed through the grouting pipe 1 into the grouting holes 3. The grouting order is: first the outer ring holes, then the bottom holes, and then the middle holes after sealing. Grouting is performed from bottom to top. Grouting is performed at intervals in each ring of holes. A combination of forward segmented grouting and backward segmented grouting is adopted.

[0076] S8, after the advanced curtain grouting is completed, the arch formwork is set up at the hole entrance, the guide pipe is embedded in advance, and then the concrete is poured;

[0077] S9, pipe roof installation: Drilling is carried out using the casing follow-up method, from high hole position to low hole position, the hole depth meets the design requirements, and the pipe roof 6 is installed;

[0078] S10, placing magnetic flower tubes in the tube shed: placing magnetic flower tubes 2 in the tube shed 6, connecting the energized wire 4 to the external controllable switch power supply 12, and adjusting the magnetic field of the magnetic flower tubes 2 by the external controllable switch power supply 12;

[0079] S11, preparing magnetic slurry:

[0080] S12, pipe roof grouting: Magnetic slurry is injected into the pipe roof 6 through the grouting pipe 1. The grouting should follow the principle of: first the two sides and then the middle, grouting in skip holes, and grouting from thin to thick;

[0081] S13, arranging pre-drilling positions of the leading small guide tube, and performing a drilling operation at the pre-drilling positions to obtain pre-grouting holes;

[0082] S14, driving the advance small conduit 5 into the pre-grouting hole and fixing the advance small conduit 5;

[0083] S15, placing a magnetic flower tube in the leading small conduit 5: placing a magnetic flower tube 2 in the leading small conduit 5, connecting the energized wire 4 to an external controllable switch power supply 12, and adjusting the magnetic field of the magnetic flower tube 2 by the external controllable switch power supply 12;

[0084] S16, preparing magnetic slurry:

[0085] S17, grouting operation is performed on the advance small guide tube 5 through the grouting pipe 1 to obtain pre-support before tunnel excavation.

[0086] Example 3:

[0087] Preferably, the magnetic slurry in S6, S11 and S16 is composed of water-based epoxy resin, curing agent, magnetic powder, cement, water, dispersant, defoaming agent and water reducer, and the specific proportions are: water-cement ratio 0.2~0.4, magnetic powder content 10%3~0%, dispersant 5%, defoaming agent 2%, water reducer 1%, epoxy resin emulsion: curing agent = 1:0.85.

[0088] Furthermore, the magnetic flower tube 2 is drilled with flower tube holes with a diameter of 10 to 16 mm, the hole spacing between the flower tube holes is 15 to 20 cm, and the flower tube holes are arranged in a plum blossom shape on the tube wall of the magnetic flower tube 2. The length of the tail of the magnetic flower tube 2 without flower tube holes is at least 150 cm.

[0089] Furthermore, the pipe shed is set within 150° of the arch, with a circumferential spacing of 20 to 30 cm, an external insertion angle of the pipe shed of 1 to 3°, and an overlap length of not less than 1 m.

[0090] Furthermore, when grouting is performed inside the steel pipes of the pipe rack 6 in S12, an exhaust pipe should be arranged, and the final pressure value should be at least 1.0 MPa and kept stable for at least 5 minutes.

[0091] Furthermore, the specific operations of S14 to S17 are:

[0092] The front end of the leading small conduit 5 is processed into a pointed cone shape, and a slurry outlet hole is provided on the conduit wall according to the design requirements;

[0093] According to the requirements of the plum blossom design, the position of the advance small guide tube 5 required for this cycle is accurately set on the excavation surface;

[0094] Use a pneumatic drill to drill holes. The external insertion angle of the leading small conduit 5 is strictly implemented according to the design requirements. The tail is welded to the steel frame. The leading small conduit 5 is parallel to the center line of the line.

[0095] The advanced small conduit 5 is pushed forward by a special jacking head, and the length of the jacking hole is not less than 90% of the pipe length. When the advanced small conduit 5 is pushed forward, the pipe mouth is protected from damage and deformation so that it can be connected to the grouting pipeline;

[0096] Check whether the openings of the 5-hole advanced small conduit meet the sealing standards to prevent leakage;

[0097] The tail end of the leading small conduit 5 is exposed to a sufficient length and is welded to the steel support;

[0098] Grouting is carried out using a grouting machine. The magnetic slurry is prepared according to the design requirements. The grouting pressure is 0.5-1.0 MPa. The completion standard is that the required grouting volume is reached in a single pipe. After the grouting is completed, the pipe mouth is sealed.

Claims

1. A construction method for magnetic slurry grouting using a pipe roof and an advanced small pipe, characterized in that: Through curtain grouting, the surrounding rock of the fault fracture zone within a range of at least 5m outside the excavation outline is solidified to prevent collapse and sudden surge. At the same time, the advance pipe shed and advance small guide pipe are set up to enhance the strength and stability of the advance support. The specific steps include: S1, advanced geological forecast: Detect the location of the fault fracture zone and groundwater in front of the tunnel face, and detect the development of karst; S2, measurement and setting out: Determine the forming position of the curtain layer, thereby determining the drilling position of the grouting holes (3), and mark the drilling positions, so that the distance between two adjacent grouting holes (3) is equal; S3, pouring grout stop wall: Determine the length of the concrete stop wall according to the faults on the tunnel face and the water discharge conditions, and cast the stop wall; S4, buried pipe: Drill to the required depth at the marked drilling location, bury the orifice pipe, and continue drilling along the orifice pipe to the designed depth; S5, place the magnetic flower tube in the drill hole: A magnetic flower tube (2) is placed in the grouting hole (3), and the energized wire (4) is connected to an external controllable switch power supply (12), and the magnetic field of the magnetic flower tube (2) is adjusted by the external controllable switch power supply (12); S6, preparing magnetic slurry: S7, Grouting: Grouting is injected into the grouting holes (3) through the grouting pipe (1). The grouting order is: first the outer ring holes, then the bottom holes, and then the middle holes after sealing. Grouting is performed from bottom to top. Grouting is performed at intervals in each ring of drilled holes. A combination of forward segmented grouting and backward segmented grouting is adopted. S8, after the advanced curtain grouting is completed, the arch formwork is set up at the hole entrance, the guide pipe is embedded in advance, and then the concrete is poured; S9, pipe roof installation: Drilling is performed using a casing follow-up method, from a high hole position to a low hole position, the hole depth meets the design requirements, and a pipe shed (6) is installed; the pipe shed is set within a 150° range of the arch, and the circumferential spacing is 20-30 cm; S10, placing magnetic flower tubes in the tube shed: A magnetic flower tube (2) is placed in a tube shed (6), and an energized conductor (4) is connected to an external controllable switch power supply (12), and the magnetic field of the magnetic flower tube (2) is adjusted by the external controllable switch power supply (12); S11, preparing magnetic slurry: S12, pipe roof grouting: Magnetic slurry is injected into the pipe shed (6) through the grouting pipe (1), and the grouting pipe (1) is inserted into the magnetic flower pipe (2); the grouting should follow the principle of: first the two sides and then the middle, skipping holes, and from thin to thick; when grouting the pipe shed, by placing the magnetic flower pipe in the pipe shed and connecting the external switch power supply to the outside, the size of the magnetic field is controlled, so that the grouting liquid can quickly fill the inside of the steel pipe and better discharge the gas in the grouting pipe; and through the overflow holes around the pipe shed, the magnetic slurry spreads to the surrounding areas, and when filling the cracks or gaps in the surrounding rock, the filling radius can be effectively reduced to avoid slurry leakage; S13, arranging pre-drilling positions of the leading small guide tube, and performing a drilling operation at the pre-drilling positions to obtain pre-grouting holes; S14, driving the advance small conduit (5) into the pre-grouting hole, and performing a fixing operation on the advance small conduit (5); S15, place the magnetic flower tube in the small leading catheter (5): A magnetic flower tube (2) is placed in the leading small conduit (5), and the energized wire (4) is connected to an external controllable switch power supply (12), and the magnetic field of the magnetic flower tube (2) is adjusted by the external controllable switch power supply (12); S16, preparing magnetic slurry: S17, grouting the advance small guide tube (5) through the grouting pipe (1), the grouting pipe (1) is inserted into the magnetic flower pipe (2); to obtain pre-support before tunnel excavation; The magnetic flower tube (2) is drilled with flower tube holes with a diameter of 10 to 16 mm, the hole spacing between the flower tube holes is 15 to 20 cm, and the flower tube holes are arranged in a plum blossom shape on the tube wall of the magnetic flower tube (2); The specific operations of S14 to S17 are: The front end of the leading small conduit (5) is processed into a pointed cone shape, and a slurry outlet hole is provided on the conduit wall according to design requirements; According to the requirements of the plum blossom design, the position of the advance small guide tube (5) required for this cycle is accurately set on the excavation surface; A pneumatic drill is used for drilling, the external insertion angle of the leading small conduit (5) is strictly constructed in accordance with the design requirements, the tail is welded to the steel frame, and the leading small conduit (5) is parallel to the center line of the line; The advance small conduit (5) is pushed forward by a special jacking head, and the length of the jacking hole is not less than 90% of the pipe length. When the advance small conduit (5) is pushed forward, the pipe mouth is protected from damage and deformation so that it can be connected to the grouting pipeline; Check whether the opening of the advance small conduit (5) meets the airtightness standard to prevent leakage; The tail end of the leading small conduit (5) is exposed to a sufficient length and is welded to the steel support; Grouting is carried out using a grouting machine. The magnetic slurry is prepared according to the design requirements. The grouting pressure is 0.5-1.0 MPa. The completion standard is that the required grouting volume is reached in a single pipe. After the grouting is completed, the pipe mouth is sealed.

2. The construction method of magnetic slurry grouting using a pipe roof and an advanced small pipe according to claim 1 is characterized in that: The magnetic slurry in S6, S11 and S16 is prepared from water-based epoxy resin, curing agent, magnetic powder, cement, water, dispersant, defoamer and water reducer, with the specific proportions being: water-cement ratio 0.2-0.4, magnetic powder content 10%-30%, dispersant 5%, defoamer 2%, water reducer 1%, epoxy resin emulsion: curing agent = 1:0.

85.

3. The construction method of magnetic slurry grouting using a pipe roof and an advanced small pipe according to claim 1 is characterized in that: When grouting is performed inside the steel pipes of the pipe rack (6) in S12, an exhaust pipe should be arranged and the final pressure value should be at least 1.0 MPa and kept stable for at least 5 minutes.

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