Deeply buried tunnel structure fracture zone directional drilling sleeve valve pipe advanced sectional grouting method

Abstract

The application discloses a kind of deep-buried tunnel structure fracture zone directional drilling sleeve valve pipe advance sectional grouting method, comprising the following steps: S1: ground directional drilling, hole channel from top to bottom includes one opening main hole public section, two opening main hole angle building section, three opening branch angle building section and three opening branch horizontal section in sequence;S2: sleeve valve pipe down and sleeve shell material filling;S3: sectional reinforcement grouting;And S4: reinforcement grouting is pressed water test after.The above-mentioned setting can improve grouting effect, shorten construction period.

Description

Technical Field

[0001] This invention belongs to the field of underground engineering geological treatment technology, specifically relating to a method for advanced segmented grouting treatment of fractured zones in deep-buried tunnel structures. Background Technology

[0002] Tunnel construction requires addressing complex geological challenges. When tunnels encounter geological environments such as fractured surrounding rock, high-pressure water-rich strata, or karst development zones during excavation, they are prone to deformation, collapse, or even water and mud inrush under the action of excavation unloading and external water pressure.

[0003] To improve the surrounding rock conditions near the working face and ensure the stability of the excavation face, it is necessary to reinforce the surrounding rock near the tunnel. Deep hole grouting reinforcement is a commonly used reinforcement method. This method involves drilling a duct into the fractured surrounding rock, high-pressure water-rich strata, or karst development area, and then injecting a solidifying material into the duct to fill the voids, enhance the bond between the soil and the structure, and improve the stability and load-bearing capacity of the structure.

[0004] After the duct is formed, the traditional method is to grout the duct using open hole grouting or forward segmented grouting. However, in open hole grouting, the grouting pressure at the bottom of the hole gradually decreases, resulting in poor grouting effect. On the other hand, forward segmented grouting has the problems of requiring repeated hole cleaning and having a long construction period. Summary of the Invention

[0005] The present invention aims to provide a method for advanced segmented grouting of directional drilling casing valve pipe in fractured zones of deep-buried tunnel structures, so as to improve the grouting effect and shorten the construction cycle.

[0006] To achieve the above objectives, the present invention provides a method for pre-segmented grouting of directional drilling casing valve pipe in fractured zones of deep-buried tunnel structures, comprising the following steps:

[0007] S1: Ground directional drilling forms a duct, which from top to bottom includes the first main hole common section, the second main hole inclined section, the third branch inclined section, and the third branch horizontal section.

[0008] S2: Lowering of the valve tube and filling of the casing material;

[0009] S2.1: Connect multiple valve tubes end to end in sequence and push them to the three-way branch horizontal section;

[0010] S2.2: After the grouting head is connected to the outlet end of the pump pipe, it is lowered to the bottom of the sleeve valve pipe. The grouting pump is used to inject the casing material from the grouting head into the space between the sleeve valve pipe and the three-section horizontal section through the pump pipe.

[0011] S2.3: After the grouting head separates from the pump pipe, the pump pipe is pulled out;

[0012] S3: Segmented reinforcement grouting;

[0013] S3.1: After connecting the grouting head to the outlet end of the pump pipe, lower it into the sleeve valve pipe to separate the grouting head from the sleeve valve pipe, and conduct a water pressure test on the side of the grouting head away from the pump pipe.

[0014] S3.2: Pump the grout for reinforcement into the sleeve valve pipe on the side of the grouting head away from the pump pipe until the grouting pressure and grouting injection rate are both stable within the threshold.

[0015] S3.3: After the grouting head separates from the pump pipe, the pump pipe is pulled out;

[0016] S3.4: Repeat S3.1 to S3.3 until the reinforcement grouting of all valve pipes is completed;

[0017] S4: Water pressure test after reinforcement grouting.

[0018] In this invention, step S1 includes the following steps:

[0019] S1.1: The first main hole common section is drilled, extending more than 5m into the weakly weathered rock mass. Grouting is carried out during the drilling process, and the first casing is installed after the hole is formed.

[0020] S1.2: Drill a slant section for the second main hole at the bottom of the common section of the first main hole. Grouting is carried out during the drilling process. After the hole is formed, the second casing is lowered and the top of the second casing is connected to the bottom of the first casing.

[0021] S1.3: Drill a three-section branch directional drilling section at the bottom of the two-section main hole directional drilling section;

[0022] S1.4: Drill holes in the horizontal section of the three-branched inclined section at the bottom of the three-branched inclined section.

[0023] In this invention, step S4 includes the following steps:

[0024] S4.1: Drill a hole on the side of the horizontal section of the three-section branch as an inspection hole;

[0025] S4.2: Perform a water pressure test inside the inspection hole.

[0026] In this invention, five sets of the three-section branch inclined sections are spaced apart at the bottom of the two-section main hole inclined sections, and each of the three-section branch horizontal sections is also arranged at intervals along the circumference of the tunnel.

[0027] In this invention, the grout used for reinforcement is a single-component cement grout with a water-cement ratio of (0.8-1.5):1.

[0028] In this invention, the side wall of the sleeve valve tube is provided with discharge ports arranged radially and penetrating along the sleeve valve tube. An end ring is fixedly provided on the outer side wall of the sleeve valve tube around each discharge port. A T-shaped rubber plug is slidably inserted into the discharge port. A limit rod is fixedly provided in the end ring and is slidably inserted into the rubber plug.

[0029] In this invention, the grouting head includes a central tube, a sealing plate, a rubber cylinder, and an end cap. One end of the central tube is threadedly connected to a pump pipe, and an mounting plate is fixedly installed on the outer wall of the other end. A connecting section is circumferentially fixed on the end of the mounting plate away from the central tube. The sealing plate and the connecting section are connected by bolts. A connecting pipe that abuts against the central tube is fixedly inserted into the sealing plate along its axial direction. The inner walls of both ends of the rubber cylinder are fixedly connected to the outer wall of one end of the central tube and the outer wall of the connecting section, respectively. A water channel is arranged radially and penetrating on the side wall of the central tube. A one-way valve for blocking the water channel is installed on the mounting plate near the end of the central tube. A column that is slidably inserted into the sealing plate is bolted to one side of the end cap. A first compression spring is sleeved on the column. The two ends of the first compression spring are respectively connected to the end of the column near the central tube and the sealing plate.

[0030] In this invention, a support is fixedly connected to the mounting plate near the central tube. The support has a through groove arranged radially along the central tube. The one-way valve includes a crossbar that is slidably inserted into the through groove. One end of the crossbar is provided with a tapered plug. A second compression spring is sleeved on the outer periphery of the crossbar between the plug and the support.

[0031] In this invention, the outer wall of the connecting pipe, the mounting plate, the sealing plate, and the inner wall of the connecting joint form an installation cavity. The inner wall of the through groove has a through hole that extends into the installation cavity. A slider is slidably connected to the side of the mounting plate away from the central pipe. A limiting rod and an insert rod are slidably inserted into the slider in sequence. A tension spring is wound around the outside of the insert rod. The two ends of the tension spring are connected to the slider and the end of the insert rod away from the mounting plate. An insertion hole opposite to the through hole is provided on the side wall of the crossbar. A baffle is fixedly provided at the end of the mounting plate away from the central pipe. A connecting rod that is slidably inserted into the baffle is fixedly provided at one end of the slider. A third compression spring is wound around the connecting rod between the slider and the baffle. A top block is fixedly provided at the end of one of the columns. The top block and the slider are respectively provided with mutually cooperating guide inclined surfaces at their respective ends.

[0032] In this invention, the bending radius of the two-section main borehole inclined section and the three-section branch inclined section is greater than 250m; the common section of the one-section main borehole and the two-section main borehole inclined section are both located 30m outside the tunnel excavation outline, and the three-section branch horizontal section is located 6m outside the tunnel excavation outline.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. By lowering the grouting head into the sleeve valve pipe, water can be injected to seal the grouting head into the sleeve valve pipe. Grouting can then be performed in sections from the bottom of the sleeve valve pipe, eliminating the need for repeated hole sweeping. This also effectively controls the grouting pressure, improves the grouting effect, and shortens the construction cycle.

[0035] 2. By utilizing the sliding limit rod and insertion rod inside the slider, the limit rod can prevent the horizontal bar from moving during and after grouting, ensuring the sealing effect of the grouting head on the sleeve valve pipe. Attached Figure Description

[0036] Figure 1 This is a simplified cross-sectional view of the present invention;

[0037] Figure 2 This is a schematic diagram of the grouting head of the present invention inside the sleeve valve tube;

[0038] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0039] Figure 4 This is a cross-sectional view of the grouting head of the present invention inside the sleeve valve tube;

[0040] Figure 5 for Figure 4 Enlarged view at point B in the middle;

[0041] Figure 6 This is a partially enlarged view of the grouting head of the present invention in use;

[0042] Figure 7 This is a partially enlarged view of the grouting head of the present invention in use, in a second state.

[0043] Figure 8 This is a half-sectional view of the central tube of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0045] The reference numerals in the accompanying drawings include: 11, common section of the main borehole; 12, inclined section of the main borehole; 13, inclined section of the branch borehole; 14, horizontal section of the branch borehole; 20, sleeve valve pipe; 21, discharge port; 22, end ring; 23, rubber plug; 24, limit bar; 30, pump pipe; 40, grouting head; 41, central pipe; 411, mounting plate; 412, connecting joint; 413, waterway; 414, support; 415, through groove; 416, through hole; 4 2. Sealing plate; 421. Connecting pipe; 43. Rubber cylinder; 44. End cap; 441. Column; 442. First compression spring; 45. Slider; 451. Limiting rod; 452. Insert rod; 453. Tension spring; 454. Connecting rod; 455. Third compression spring; 46. Baffle; 47. Top block; 51. First-opening sleeve; 52. Second-opening sleeve; 60. Inspection hole; 70. One-way valve; 71. Crossbar; 711. Insertion hole; 72. Plug; 73. Second compression spring.

[0046] Example:

[0047] Appendix Figures 1-8 As shown, this invention discloses a method for pre-grouting segmented directional drilling casing valve pipe in fractured zones of deeply buried tunnels, comprising the following steps:

[0048] S1: Ground directional drilling forms a duct, which from top to bottom includes a common section of the main hole 11, a directional section of the main hole 12, a directional section of the branch hole 13, and a horizontal section of the branch hole 14.

[0049] S2: Lowering of valve tube 20 and filling of casing material;

[0050] S2.1: Connect multiple sleeve valve pipes 20 end to end in sequence and push them to the three-way branch horizontal section 14;

[0051] S2.2: After the outlet end of the pump pipe 30 is connected to the grouting head 40, it is lowered to the bottom of the sleeve valve pipe 20. The grouting pump is used to inject the casing material from the grouting head 40 into the space between the sleeve valve pipe 20 and the three-section horizontal section 14 through the pump pipe 30.

[0052] S2.3: After the grouting head 40 separates from the pump pipe 30, the pump pipe 30 is pulled out;

[0053] S3: Segmented reinforcement grouting;

[0054] S3.1: After the grouting head 40 is connected to the outlet end of the pump pipe 30, it is lowered into the sleeve valve pipe 20 so that the grouting head 40 separates the sleeve valve pipe 20, and a water pressure test is performed on the side of the grouting head 40 away from the pump pipe 30.

[0055] S3.2: Pump the grout for reinforcement into the sleeve valve pipe 20 on the side of the grouting head 40 away from the pump pipe 30 until the grouting pressure and grouting injection rate are both stable within the threshold.

[0056] S3.3: After the grouting head 40 is separated from the pump pipe 30, the pump pipe 30 is pulled out;

[0057] S3.4: Repeat S3.1 to S3.3 until the reinforcement grouting of all valve pipes 20 is completed;

[0058] S4: Water pressure test after reinforcement grouting.

[0059] In this embodiment, the grouting injection rate limit in S3.2 is set to 50-60 L / min.

[0060] In this embodiment, step S1 includes the following steps:

[0061] S1.1: The first main borehole, common section 11, extends more than 5m into the weakly weathered rock mass. Grouting is carried out during the drilling process. Clay-cement grout is used for grouting, and the density of the clay grout is controlled at 1.12×10⁻⁶. 3 kg / m 3 ~1.24×10 3 kg / m 3 Between these amounts, the amount of cement added per cubic meter of grout ranges from 100 kg to 300 kg, while the amount of water glass added is 10 L / m³. 3 ~40L / m 3 After drilling, a casing 51 is installed for cementing and waiting for it to solidify.

[0062] S1.2: Drill the second main hole slant section 12 at the bottom of the common section 11 of the first main hole. Grouting is carried out during the drilling process. After the hole is formed, the second casing 52 is lowered in, cementing is carried out and waiting for solidification, and the top of the second casing 52 is connected to the bottom of the first casing 51.

[0063] S1.3: Drill a three-section branch directional drilling section 13 at the bottom of the two-section main hole directional drilling section 12;

[0064] S1.4: Drill holes in the horizontal section 14 of the three-branched inclined section 13 at the bottom of the three-branched inclined section 13;

[0065] During drilling, drilling parameters are recorded to make a preliminary judgment on the formation conditions. The drilling logging is performed to record one point every 1m of drilling throughout the well, so as to discover special parts such as fractured zones and intact formations at any time.

[0066] During construction, real-time monitoring of drilling measurement data is conducted, and the design trajectory is dynamically compared to ensure timely adjustment of drill string assembly and drilling parameters, thereby ensuring the accuracy of the borehole trajectory.

[0067] In this embodiment, step S4 includes the following steps:

[0068] S4.1: Drill a hole on the side of the horizontal section 14 of the three-section branch as an inspection hole 60, and at the same time take a core sample from the target formation;

[0069] S4.2: Perform acoustic testing and television video recording in the test hole, and perform a water pressure test in the inspection hole 60.

[0070] In this embodiment, five sets of the three-section branch inclined section 13 are spaced apart at the bottom of the two-section main hole inclined section 12, and each of the three-section branch horizontal sections 14 is also spaced apart along the circumference of the tunnel.

[0071] In this embodiment, the grout used for reinforcement is a single-component cement grout with a water-cement ratio of (0.8-1.5):1.

[0072] In this embodiment, the side wall of the sleeve valve tube 20 is provided with discharge ports 21 arranged radially and penetrating along the sleeve valve tube 20. An end ring 22 is fixedly provided on the outer periphery of each discharge port 21 on the outer side wall of the sleeve valve tube 20. A T-shaped rubber plug 23 is slidably inserted into the discharge port 21. A limiting rod 24 is fixedly provided in the end ring 22. The limiting rod 24 is slidably inserted into the rubber plug 23.

[0073] In this embodiment, the grouting head 40 includes a central tube 41, a sealing plate 42, a rubber cylinder 43, and an end cap 44. One end of the central tube 41 is threadedly connected to the pump pipe 30, and an mounting plate 411 is fixedly installed on the outer wall of the other end. A connecting joint 412 is circumferentially fixedly installed on the end of the mounting plate 411 away from the central tube 41. The sealing plate 42 is bolted to the connecting joint 412. A connecting pipe 421 that abuts against the central tube 41 is fixedly inserted into the sealing plate 42 along its axial direction. The inner walls of both ends of the rubber cylinder 43 are respectively connected to the central tube 41. One end of the central tube 41 is fixedly connected to the outer wall of the connecting joint 412. The side wall of the central tube 41 is provided with a water channel 413 arranged radially and passing through it. The mounting plate 411 is provided with a one-way valve 70 for blocking the water channel 413 near the end of the central tube 41. The end cap 44 is connected by bolts to a column 441 that is slidably inserted into the sealing plate 42. The column 441 is fitted with a first compression spring 442. The two ends of the first compression spring 442 are respectively connected to the end of the column 441 near the central tube 41 and the sealing plate 42.

[0074] In this embodiment, a support 414 is fixedly connected to the mounting plate 411 near the central tube 41. The support 414 is provided with a through groove 415 radially along the central tube 41. The one-way valve 70 includes a crossbar 71 slidably inserted into the through groove 415. One end of the crossbar 71 is provided with a tapered plug 72. A second compression spring 73 is sleeved on the outer periphery of the crossbar 71 between the plug 72 and the support 414.

[0075] In this embodiment, the outer wall of the connecting pipe 421, the mounting plate 411, the sealing plate 42, and the inner wall of the connecting joint 412 form an installation cavity. The inner wall of the through groove 415 has a through hole 416 that extends into the installation cavity. A slider 45 is slidably connected to the side of the mounting plate 411 away from the central pipe 41. A sliding groove is provided on the side of the mounting plate 411 away from the central pipe 41. A slide rail is fixedly provided on the side wall of the slider 45 and slidably embedded in the sliding groove. A limiting rod 451 and an insert rod 452 are slidably inserted into the slider 45 in sequence. A tension spring 453 is wound around the outside of the insert rod 452. The two ends of the tension spring 453 are connected to the slider 45 and the end of the insert rod 452 away from the mounting plate 411. The side wall of the crossbar 71 is provided with a through hole 416. For the corresponding insertion hole 711, a baffle 46 is fixedly installed at the end of the mounting plate 411 away from the central tube 41. A connecting rod 454 that is slidably inserted into the baffle 46 is fixedly installed at one end of the slider 45. A third compression spring 455 is wound around the connecting rod 454 between the slider 45 and the baffle 46. A top block 47 is fixedly installed at the end of one of the columns 441. The top block 47 and the slider 45 are respectively provided with mutually cooperating guide inclined surfaces at their respective ends. A limit block is fixedly installed on the side of the mounting plate 411 away from the central tube 41 and on the side of the slider 45 away from the baffle 46. The length of the limit rod 451 is greater than the length of the through hole 416, and the length of the limit rod 451 is less than the sum of the lengths of the through hole 416 and the insertion hole 711.

[0076] In this embodiment, the bending radius of the two-section main borehole inclined section 12 and the three-section branch inclined section 13 is greater than 250m; the one-section main borehole common section 11 and the two-section main borehole inclined section 12 are both located 30m outside the tunnel excavation outline, and the three-section branch horizontal section 14 is located 6m outside the tunnel excavation outline.

[0077] When filling the casing material, the grouting head 40 is first pushed to the bottom of the sleeve valve pipe 20, and then water is pumped into the pump pipe 30. After the water flows into the central pipe 41, the end cap 44 prevents the water from flowing out of the connecting pipe 421. Because the elastic force of the first compression spring 442 is greater than that of the second compression spring 73, the water first pushes open the plug 72 and fills the gap between the rubber cylinder 43 and the outer wall of the central pipe 41, causing the rubber cylinder 43 to expand. When the outer wall of the rubber cylinder 43 presses against the inner wall of the sleeve valve pipe 20, water continues to be pumped into the pump pipe 30. After the water pressure in the central pipe 41 rises, the water pushes the end cap 44 to move. After the water flows out through the gap between the end cap 44 and the connecting pipe 421, the second compression spring 73 pushes the plug 72 to reset, blocking the water channel 413. At this time, the insertion hole 711 is aligned with the through hole 416.

[0078] In the initial state, the first compression spring 442 pushes the column 441 against the slider 45. When the end cap 44 moves, causing the column 441 to move, the third compression spring 455 pushes the slider 45 towards the connecting pipe 421. When the limiting rod 451 is aligned with the through hole 416, the tension spring 453 pulls the insertion rod 452 to push the limiting rod 451 into the through hole 416 and the insertion hole 711. At this time, the end of the insertion rod 452 is located outside the through hole 416. Then, the pumping stops and water flows through the pump pipe 30. Pump casing material into the grouting head 40. The casing material flows directly into the gap between the sleeve valve pipe 20 and the three-section horizontal section 14. After the casing material fills the three-section horizontal section 14, stop grouting. The first compression spring 442 pushes the column 441 to pull the end cover 44 to cover the connecting pipe 421 again. The top block 47 pushes the slider 45 to reset. At this time, the end of the limit rod 451 abuts against the side wall of the slider 45, separating the pump pipe 30 and the grouting head 40. Then pull out the pump pipe 30 and clean the pump pipe 30.

[0079] After the casing material has solidified for 3 days, the grouting head 40 is sent into the casing valve pipe 20 through the pump pipe 30. Water is pumped into the pump pipe 30 to make the rubber cylinder 43 press against the inner wall of the casing valve pipe 20. Water is then pumped into the casing valve pipe 20 to conduct a water pressure test. After the water pressure in the casing valve pipe 20 rises, it pushes the rubber stopper 23 to break the limiting rod 24 and penetrate the casing material into the target formation. After the water pressure test is completed, the reinforcement grout is pumped into the casing valve pipe 20 so that the reinforcement grout passes through the casing material and penetrates into the target formation to reinforce the target formation. After the grouting pressure and grouting injection rate are both stable within the threshold, the pump pipe 30 and the grouting head 40 are separated, and the pump pipe 30 is pulled out and cleaned.

[0080] Repeat the above arrangement until the entire section of the sleeve valve pipe 20 is reinforced with grout, then separate the three-section sleeve from the sleeve valve pipe 20 and pull it out.

[0081] The parts of the device not covered herein are the same as or can be implemented using existing technologies.

[0082] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions or characteristics in the solutions are not described in detail here. It should be noted that those skilled in the art can make several modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention, without affecting the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for pre-grouting segmented sections of directional drilling casing valve pipe in fractured zones of deep-buried tunnels, characterized in that... Includes the following steps: S1: Ground directional drilling forms a duct, which from top to bottom includes the first main hole common section, the second main hole inclined section, the third branch inclined section, and the third branch horizontal section. S2: Lowering of the valve tube and filling of the casing material; S2.1: Connect multiple valve tubes end to end in sequence and push them to the three-way branch horizontal section; S2.2: After the grouting head is connected to the outlet end of the pump pipe, it is lowered to the bottom of the sleeve valve pipe. The grouting pump is used to inject the casing material from the grouting head into the space between the sleeve valve pipe and the three-section horizontal section through the pump pipe. S2.3: After the grouting head separates from the pump pipe, the pump pipe is pulled out; S3: Segmented reinforcement grouting; S3.1: After connecting the grouting head to the outlet end of the pump pipe, lower it into the sleeve valve pipe to separate the grouting head from the sleeve valve pipe, and conduct a water pressure test on the side of the grouting head away from the pump pipe. S3.2: Pump the grout for reinforcement into the sleeve valve pipe on the side of the grouting head away from the pump pipe until the grouting pressure and grouting injection rate are both stable within the threshold. S3.3: After the grouting head separates from the pump pipe, the pump pipe is pulled out; S3.4: Repeat S3.1 to S3.3 until the reinforcement grouting of all valve pipes is completed; S4: Water pressure test after reinforcement grouting; The grouting head includes a central tube, a sealing plate, a rubber cylinder, and an end cap. One end of the central tube is threaded to a pump pipe, and an mounting plate is fixedly installed on the outer wall of the other end. A connecting section is circumferentially fixed on the mounting plate at the end away from the central tube. The sealing plate is bolted to the connecting section. A connecting pipe that abuts against the central tube is fixedly inserted into the sealing plate along its axial direction. The inner walls of both ends of the rubber cylinder are fixedly connected to the outer wall of one end of the central tube and the outer wall of the connecting section, respectively. A water channel is provided on the side wall of the central tube, arranged radially and penetrating through it. A one-way valve for blocking the water channel is provided on the mounting plate near the central tube. A column slidably inserted into the sealing plate is bolted to one side of the end cap. A first compression spring is sleeved on the column, and the two ends of the first compression spring are respectively connected to the end of the column near the central tube and the sealing plate. A support is fixedly connected to the mounting plate near the central tube. The support has a through groove arranged radially along the central tube. The one-way valve... The system includes a crossbar slidably inserted into a through groove, with a tapered plug at one end. A second compression spring is sleeved around the crossbar between the plug and the support. The outer wall of the connecting pipe, the mounting plate, the sealing plate, and the inner wall of the connecting joint form an installation cavity. A through hole extending into the installation cavity is opened on the inner wall of the through groove. A slider is slidably connected to the side of the mounting plate away from the central pipe. A limiting rod and an insert rod are slidably inserted into the slider in sequence. A tension spring is wound around the insert rod, with both ends of the tension spring connecting the slider and the end of the insert rod away from the mounting plate. An insertion hole opposite to the through hole is provided on the side wall of the crossbar. A baffle is fixedly provided at the end of the mounting plate away from the central pipe. A connecting rod is fixedly provided at one end of the slider and slidably inserted into the baffle. A third compression spring is wound around the connecting rod between the slider and the baffle. A top block is fixedly provided at one end of the column. The top block and the slider are respectively provided with mutually cooperating guide inclined surfaces at their respective ends.

2. The method for pre-grouting segmented directional drilling casing valve pipe in fractured zones of deep-buried tunnels as described in claim 1, characterized in that: S1 includes the following steps: S1.1: The first main hole common section is drilled, extending more than 5m into the weakly weathered rock mass. Grouting is carried out during the drilling process, and the first casing is installed after the hole is formed. S1.2: Drill a slant section for the second main hole at the bottom of the common section of the first main hole. Grouting is carried out during the drilling process. After the hole is formed, the second casing is lowered and the top of the second casing is connected to the bottom of the first casing. S1.3: Drill a three-section branch directional drilling section at the bottom of the two-section main hole directional drilling section; S1.4: Drill holes in the horizontal section of the three-branched inclined section at the bottom of the three-branched inclined section.

3. The method for pre-grouting segmented directional drilling casing valve pipe in fractured zones of deep-buried tunnels as described in claim 1, characterized in that: S4 includes the following steps: S4.1: Drill a hole on the side of the horizontal section of the three-section branch as an inspection hole; S4.2: Perform a water pressure test inside the inspection hole.

4. The method for pre-grouting segmented directional drilling casing valve pipe in fractured zones of deep-buried tunnels as described in claim 1, characterized in that: The three-section branch inclined section is provided in five sets at intervals at the bottom of the two-section main hole inclined section, and each of the three-section branch horizontal sections is also arranged at intervals along the circumference of the tunnel.

5. The method for advance segmented grouting of directional drilling casing valve pipe in fractured zones of deep-buried tunnels as described in claim 1, characterized in that: The grout used for reinforcement is a single-component cement grout with a water-cement ratio of (0.8-1.5):

1.

6. The method for pre-grouting segmented directional drilling casing valve pipe in fractured zones of deep-buried tunnels as described in claim 1, characterized in that: The side wall of the sleeve valve tube is provided with discharge ports arranged radially and through the sleeve valve tube at intervals. An end ring is fixedly provided on the outer side wall of the sleeve valve tube at the outer periphery of each discharge port. A T-shaped rubber plug is slidably inserted into the discharge port. A limit bar is fixedly provided in the end ring and is slidably inserted into the rubber plug.

7. The method for advance segmented grouting of directional drilling casing valve pipe in fractured zones of deep-buried tunnels as described in claim 1, characterized in that: The bending radius of the two-section main borehole inclined section and the three-section branch inclined section is greater than 250m; the common section of the one-section main borehole and the two-section main borehole inclined section are both located 30m outside the tunnel excavation outline, and the three-section branch horizontal section is located 6m outside the tunnel excavation outline.

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