Synchronous grouting system suitable for underground excavation structure

Abstract

The invention relates to the technical field of underground excavation tunnel construction, and discloses a synchronous grouting system suitable for an underground excavation structure, the synchronous grouting system comprises a primary support, a geotechnical cloth buffer layer, a waterproof plate, a template and a grouting device, the geotechnical cloth buffer layer is laid on the primary support, the waterproof plate is laid on the geotechnical cloth buffer layer, and a secondary lining is formed between the template and the waterproof plate through pouring; the grouting device is installed on the formwork, one end of the grouting device makes contact with the waterproof plate, and the other end of the grouting device extends out of the formwork. And after the secondary lining is initially set, grouting is conducted in the grouting device. According to the method, through synchronous grouting, a void area between the back of the structure and a waterproof layer can be effectively filled, water leakage caused by void is avoided, and due to the fact that the interval time between grouting operation and structural concrete pouring is short, grout and concrete can be fused into a whole, and the integrity between the structure and a grouting material is improved; and meanwhile, the slurry has good adhesive property and mechanical property and is tightly attached to water, and no water channeling channel exists between the slurry and the water.

Description

Technical Field

[0001] The present invention relates to the technical field of mined tunnel construction, and more specifically, to a synchronous grouting system applicable to mined structures. Background Art

[0002] With the continuous development of the urbanization process, the construction of rail transit has entered a period of rapid rise. However, with the increase in the operation years of urban subways, the phenomenon of water leakage and seepage is increasing continuously. One of the very important reasons is that there may be a non-close contact situation between the structure and the waterproof layer due to defects in the pouring process or improper construction operations, forming a water channeling path. Especially for mined structures, it is easy to have voids behind the lining arch crown, and even the thickness is seriously insufficient, which affects the stability of the tunnel lining structure and the driving safety.

[0003] Currently, for the problem of non-close contact between the secondary lining and the waterproof layer of mined structures, the main method is to use backfill grouting. The traditional grouting system includes a grouting base and a grouting conduit. The grouting base needs to be hot-melt welded to the waterproof layer. The open end of the grouting conduit is generally blocked with a sealing cap and tightly sealed with sealing tape and then buried in the concrete (or separately sealed with sealing plastic tape). After the formwork is removed, the sealing tape on the surface of the open end and the concrete need to be broken to expose the grouting conduit. These processes are relatively complex and pose a great test to the construction level of the construction unit. If the construction operation is improper, it is very likely to affect the use effect. Moreover, the grouting starts only after the concrete reaches 100% of the design strength after demoulding, which makes it difficult for the injected grout to bond well with the original secondary lining concrete, and they are still "two layers of skin", and the integrity of the structure is relatively poor. At the same time, since the backfill grouting is carried out after demoulding, it is often necessary to set up scaffolds again, which increases the construction difficulty and construction cost.

[0004] Therefore, it is necessary to propose a synchronous grouting system applicable to mined structures to at least partially solve the problems existing in the prior art and enable the structure, especially between the secondary lining and the waterproof board, to be in good close contact. Summary of the Invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description section. The Summary of the Invention section of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0006] To at least partially solve the above problems, the present invention provides a synchronous grouting system applicable to mined structures, including: Primary support, geotextile buffer layer, waterproof board, formwork and grouting device. The geotextile buffer layer is laid on the primary support, the waterproof board is laid on the geotextile buffer layer, the secondary lining is formed by pouring between the formwork and the waterproof board, the grouting device is installed on the formwork, one end of the grouting device contacts the waterproof board, and the other end extends out of the formwork; after the secondary lining starts to set, grout is injected into the grouting device.

[0007] Preferably, structural main reinforcement bars, structural distribution reinforcement bars and structural stirrups are tied in the secondary lining. A number of formwork openings are provided on the formwork. The center of the formwork opening coincides with the center of the square formed by the structural main reinforcement bars and structural distribution reinforcement bars. The grouting device is installed in the formwork opening.

[0008] Preferably, longitudinal construction joints and circumferential construction joints are formed during the installation of the formwork. The longitudinal spacing and circumferential spacing of the formwork openings are set to 4 - 6 m. Formwork openings are provided at a distance of 500 mm from the joints on both sides of the circumferential construction joint and above and below the longitudinal construction joint.

[0009] Preferably, the grouting device includes: a fixed flange, a detachable flange and a grouting pipe. The fixed flange is connected to the formwork; the detachable flange is connected to the outside of the fixed flange through fastening bolts; one end of the grouting pipe is screwed to the neck of the detachable flange, and the other end extends into the secondary lining and contacts the waterproof board. The detachable flange and the grouting pipe are connected in a central communication manner to form a grouting channel.

[0010] Preferably, the fixed flange is circular, including a central opening of the fixed flange and at least four bolt holes of the fixed flange. The multiple bolt holes of the fixed flange are evenly arranged along the circumferential direction of the fixed flange.

[0011] Preferably, the detachable flange is circular, including a detachable flange panel, a detachable flange neck and a detachable flange neck sleeve connected in sequence. A central opening of the detachable flange penetrates through the detachable flange. At least four bolt holes of the detachable flange are evenly arranged along the circumferential direction of the detachable flange panel. The bolt holes of the detachable flange correspond to the bolt holes of the fixed flange one by one and are connected through fastening bolts; the detachable flange neck is sleeved in the formwork opening and the central opening of the fixed flange; the detachable flange neck sleeve is connected to the center of the detachable flange neck and protrudes from its surface. The thickness of the detachable flange neck is equal to the sum of the thicknesses of the formwork and the fixed flange; the detachable flange neck sleeve is provided with an external thread.

[0012] Preferably, the grouting pipe includes a water-stop flange and a rubber suction cup. The annular water-stop flange is connected to the middle of the grouting pipe. One end of the grouting pipe is provided with an internal thread. The internal thread of the grouting pipe is connected to the external thread of the detachable flange neck sleeve and the connection length is adjustable; the other end of the grouting pipe is provided with a rubber suction cup, and the rubber suction cup contacts the waterproof board.

[0013] Preferably, the grouting device further includes: a screw cap. After the fixed flange, the detachable flange and the formwork are removed, the screw cap is screwed to the grouting pipe.

[0014] Preferably, the base surface of the primary support is leveled. After treatment, the flatness meets the requirement of D / L≤1 / 8, where D is the maximum depth of the depression between two adjacent convex surfaces, and L is the shortest distance between two adjacent convex surfaces.

[0015] Preferably, the geotextile buffer layer is fixed to the base surface of the primary support by cement nails. An iron gasket and a plastic round gasket are arranged between the end of the cement nail and the geotextile buffer layer. The center of the plastic round gasket is crimped on the geotextile buffer layer and forms a groove for accommodating the iron gasket at the center. The periphery of the plastic round gasket protrudes to fit the protrusions on the waterproof board, and the waterproof board is welded to the plastic round gasket.

[0016] Compared with the prior art, the present invention provides a synchronous grouting system applicable to the mined - out structure, which has at least the following beneficial effects: 1. Through synchronous grouting, the void area between the back of the structure and the waterproof layer can be effectively filled, avoiding water leakage caused by voids. And because the interval between the grouting operation and the casting of structural concrete is short, the grout and the concrete can be integrated into one body, improving the integrity between the structure and the grouting material. At the same time, the grout has good bonding performance and mechanical properties, and is closely attached to the waterproof layer, and there is no water - channeling passage between them.

[0017] 2. Since the formwork is removed after grouting, the operation of setting up scaffolds for later backfill grouting is avoided, improving the construction efficiency and saving costs.

[0018] 3. This grouting pipe can be grouted repeatedly. If water leakage is found during the later operation, only need to open the nearby grouting holes to grout again, avoiding the disadvantages of long construction period, high cost, affecting the structural safety and great social impact caused by later drilling.

[0019] 4. A water - stop flange is arranged in the middle of the grouting pipe, which can meet the waterproof requirements between the grouting pipe and the surrounding concrete.

[0020] For the synchronous grouting system applicable to the mined - out structure described in the present invention, other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings: Figure 1 It is a schematic diagram of the fixing method of the waterproof board in the present invention; Figure 2 It is a schematic cross - sectional layout diagram of the synchronous grouting system in the present invention; Figure 3It is a longitudinal section layout schematic diagram of the synchronous grouting system in the present invention; Figure 4 It is a sectional schematic diagram after the installation of the grouting device in the present invention; Figure 5 It is a sectional schematic diagram after the installation of the formwork in the present invention; Figure 6 It is a sectional schematic diagram of the grouting pipe in the present invention; Figure 7 It is a plan schematic diagram of the fixed flange in the present invention; Figure 8 It is a plan schematic diagram of the detachable flange in the present invention; Figure 9 It is a sectional schematic diagram of the fixed flange and the detachable flange in the present invention; Figure 10 It is a sectional schematic diagram of the screw cap in the present invention.

[0022] In the figure: 1, primary support; 2, geotextile buffer layer; 3, waterproof board; 4, cement nail; 5, iron gasket; 6, plastic round gasket; 7, secondary lining; 8, grouting device; 9, longitudinal construction joint; 10, circumferential construction joint; 11, formwork; 12, formwork opening; 13, structural main reinforcement; 14, structural partial reinforcement; 15, structural stirrup; 16, grouting pipe; 17, water stop flange; 18, rubber suction cup; 19, internal thread; 20, fixed flange; 21, fixed flange center opening; 22, fixed flange bolt hole; 23, detachable flange; 24, detachable flange center opening; 25, detachable flange bolt hole; 26, detachable flange panel; 27, detachable flange neck; 28, detachable flange neck sleeve; 29, external thread; 30, fastening bolt; 31, screw cap. Detailed implementation manners

[0023] The following further elaborates on the present invention in conjunction with the drawings and embodiments, so that those skilled in the art can implement it with reference to the text of the specification.

[0024] It should be understood that terms such as "having", "including", and "comprising" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0025] Embodiment 1: As Figures 1 - 10 shown, the present invention provides a synchronous grouting system applicable to a mined structure, including: The primary support 1, geotextile buffer layer 2, waterproof board 3, formwork 11 and grouting device 8. The geotextile buffer layer 2 is laid on the primary support 1, the waterproof board 3 is laid on the geotextile buffer layer 2, and the secondary lining 7 is formed by pouring between the formwork 11 and the waterproof board 3. The grouting device 8 is installed on the formwork 11. One end of the grouting device 8 contacts the waterproof board 3, and the other end extends out of the formwork 11; after the secondary lining 7 begins to set, grout is injected into the grouting device 8.

[0026] Among them, structural main reinforcement bars 13, structural distribution reinforcement bars 14 and structural stirrups 15 are tied in the secondary lining 7. A number of formwork openings 12 are provided on the formwork 11. The center of the formwork opening 12 coincides with the center of the square formed by the structural main reinforcement bars 13 and the structural distribution reinforcement bars 14. The grouting device 8 is installed in the formwork opening 12.

[0027] Among them, when the formwork 11 is installed, longitudinal construction joints 9 and circumferential construction joints 10 are formed. The longitudinal spacing and circumferential spacing of the formwork openings 12 are set to 4 - 6 m. On both sides of the circumferential construction joint 10 and above and below the longitudinal construction joint 9, formwork openings 12 are provided at a distance of 500 mm from the joint.

[0028] Among them, the grouting device 8 includes: a fixed flange 20, a detachable flange 23 and a grouting pipe 16. The fixed flange 20 is connected to the formwork 11; the detachable flange 23 is connected to the outside of the fixed flange 20 through a fastening bolt 30; one end of the grouting pipe 16 is screwed to the neck of the detachable flange 23, and the other end extends into the secondary lining 7 and contacts the waterproof board 3. The detachable flange 23 and the grouting pipe 16 are centrally connected and arranged to form a grouting channel.

[0029] Among them, the fixed flange 20 is set to be circular, including a fixed flange center opening 21 and at least four fixed flange bolt holes 22. The multiple fixed flange bolt holes 22 are evenly arranged along the circumferential direction of the fixed flange 20.

[0030] Among them, the detachable flange 23 is set to be circular, including a detachable flange panel 26, a detachable flange neck 27 and a detachable flange neck sleeve 28 connected in sequence. A detachable flange center opening 24 runs through the center of the detachable flange 23. At least four detachable flange bolt holes 25 are evenly arranged along the circumferential direction of the detachable flange panel 26. The detachable flange bolt holes 25 correspond one-to-one with the fixed flange bolt holes 22 and are connected through fastening bolts 30; the detachable flange neck 27 is sleeved in the formwork opening 12 and the fixed flange center opening 21; the detachable flange neck sleeve 28 is connected to the center of the detachable flange neck 27 and protrudes from its surface. The thickness of the detachable flange neck 27 is equal to the sum of the thicknesses of the formwork 11 and the fixed flange 20; the detachable flange neck sleeve 28 is provided with an external thread 29.

[0031] Among them, the grouting pipe 16 includes a water-stop flange 17 and a rubber suction cup 18. The annular water-stop flange 17 is connected to the middle of the grouting pipe 16. One end of the grouting pipe 16 is provided with an internal thread 19, and the internal thread 19 of the grouting pipe 16 is connected to the external thread 29 of the detachable flange neck sleeve 28 with an adjustable connection length. The other end of the grouting pipe 16 is provided with a rubber suction cup 18, and the rubber suction cup 18 contacts the waterproof board 3.

[0032] Among them, the grouting device 8 further includes: a screw cap 31. After the fixed flange 20, the detachable flange 23 and the formwork 11 are removed, the screw cap 31 is screwed to the grouting pipe 16.

[0033] Among them, the base surface of the primary support 1 is leveled. The flatness after treatment satisfies D / L≤1 / 8, where D is the maximum depth of the recess between two adjacent convex surfaces, and L is the shortest distance between two adjacent convex surfaces.

[0034] Among them, the geotextile buffer layer 2 is fixed to the base surface of the primary support 1 by cement nails 4. An iron gasket 5 and a plastic round gasket 6 are arranged between the end of the cement nail 4 and the geotextile buffer layer 2. The center of the plastic round gasket 6 is crimped on the geotextile buffer layer 2 and forms a groove for accommodating the iron gasket 5 at the center. The periphery of the plastic round gasket 6 protrudes to fit the protrusions on the waterproof board 3, and the waterproof board 3 is welded to the plastic round gasket 6.

[0035] The working principle and beneficial effects of the above technical solution are as follows: A synchronous grouting system applicable to a mined structure according to the present invention includes the following steps when the system is implemented: Step 1: According to the construction segments, formwork length, and steel bar arrangement of the mined structure, a number of formworks 11 are customized, and formwork openings 12 with a diameter of 100 mm are arranged at appropriate positions in the middle. The center of the opening is consistent with the center of the square formed by the structural main bars 13 and the structural distribution bars 14.

[0036] Step 2: Customize the fixed flange 20, detachable flange 23 and grouting pipe 16 in combination with the size of the template opening 12 in Step 1. The fixed flange 20 has a thickness of 10 mm, is circular in shape, the diameter of the central opening 21 of the fixed flange is 100 mm, and there are at least 4 fixed flange bolt holes 22. The detachable flange 23 is circular and is divided into two parts: a detachable flange panel 26 and a detachable flange neck 27. The diameter of the central opening 24 of the detachable flange is 24 mm, the thickness of the detachable flange panel 26 is 10 mm, there are at least 4 detachable flange bolt holes 25 and the hole positions correspond to the fixed flange bolt holes 22. The outer diameter of the detachable flange neck 27 is 98 mm and can be inserted into the template opening 12 and the central opening 21 of the fixed flange. A detachable flange neck sleeve 28 protruding from the surface of the detachable flange neck 27 is provided at the center of the detachable flange neck 27. The total thickness of the detachable flange neck 27 should be the sum of the thicknesses of the template 11 and the fixed flange 20. The inner diameter of the grouting pipe 16 is 32 mm, the wall thickness is 3 mm, and a water stop flange 17 with a thickness of 3 mm and a width of 20 mm is provided in the middle. The detachable flange neck sleeve 28 is provided with an external thread 29, and one end of the grouting pipe 16 is provided with an internal thread 19. The external thread 29 and the internal thread 19 can be connected to adjust the connection length between the detachable flange 23 and the grouting pipe 16. The other end of the grouting pipe 16 is sleeved with a rubber suction cup 18.

[0037] Step 3: Level the base surface of the primary support 1 and carry out leveling treatment. The treatment method can adopt shotcrete or the method of plastering with 1:2.5 cement mortar. Generally, the method of plastering with cement mortar is preferred. The treated base surface should meet the following conditions: D / L ≤ 1 / 8, where D: the maximum depth of the depression between two adjacent convex surfaces; L: the shortest distance between two adjacent convex surfaces.

[0038] Step 4: Lay the geotextile buffer layer 2 and fix the geotextile buffer layer 2 on the base surface of the primary support 1 with cement nails 4, iron washers 5 and plastic round washers 6 matching the waterproof board 3. The fixing points are arranged in a regular plum blossom shape. All plastic round washers 6 should be fixed at the concave parts of the base layer to avoid local over-tightening when fixing the waterproof board 3.

[0039] Step 5: Lay the waterproof board 3. The waterproof board 3 is manually welded to the plastic round washer 6 with a hot air welding gun. The welding should be firm and reliable to avoid the waterproof board 3 falling off during the pouring and vibration of concrete. It is strictly prohibited to weld through the waterproof board 3 during welding. The joints between the waterproof boards 3 are hot melt welded with double welds, and the lap width is 10 cm.

[0040] Step 6: Conduct an airtightness test on the lap joint of the waterproof board 3. Use a leak detector, the inflation pressure is 0.25 Mpa, and maintain this pressure for no less than 15 minutes. A pressure drop of 10% is allowed. If the pressure continues to drop, the air leakage location should be found and the air leakage location should be fully repaired by manual welding.

[0041] Step 7: Tie the steel bars of the secondary lining 7 (including the structural main bars 13, structural distribution bars 14 and structural stirrups 15), and then install the formwork 11, controlling the longitudinal and circumferential spacings of the formwork openings 12 within 4 - 6 meters. Meanwhile, arrange the formwork openings 12 at a distance of 500 mm from the joints on both sides of the circumferential construction joint 10 and above the longitudinal construction joint 9. When using a formwork trolley for construction, drill holes at the corresponding positions of the formwork trolley according to the above requirements.

[0042] Step 8: Align the central opening 21 of the fixed flange with the formwork opening 12 and connect and fix it to the formwork 11. If it is a steel formwork, use welding; if it is a wooden formwork, use screw connection (without penetrating the formwork).

[0043] Step 9: Measure the vertical distance between the waterproof board 3 at the projection position of the formwork opening 12 and the inner skin of the formwork 11. Connect the detachable flange 23 and the grouting pipe 16 through the external thread 29 and the internal thread 19, and by adjusting the external thread 29 and the internal thread 19, make the distance between the inner skin of the detachable flange 23 and the outermost rubber suction cup 18 of the grouting pipe 16 consistent with the measured distance.

[0044] Step 10: Insert the detachable flange 23 and the grouting pipe 16 into the formwork opening 12, fit the detachable flange panel 22 with the fixed flange 20, and rotate the detachable flange 23 to align the detachable flange bolt holes 25 and the fixed flange bolt holes 22, and connect the detachable flange 23 and the fixed flange 20 by tightening the bolts 30.

[0045] Step 11: Pour the secondary lining 7. During the pouring process, pay attention to avoiding the vibration rod touching the grouting pipe 16.

[0046] Step 12: Grout. After the secondary lining 7 begins to set, grout into the grouting pipe 16 through the central opening 24 of the detachable flange, and pay attention to controlling the grouting pressure during the grouting process.

[0047] Step 13: Use ground penetrating radar to scan for voids. After the secondary lining 7 reaches the design strength, use ground penetrating radar to scan the compactness of the poured secondary lining 7. If there are voids or non - compact areas, the nearby grouting pipe 16 can be used to grout again according to the requirements of Step 12 until the secondary lining 7 is compact.

[0048] Step 14: After Step 13 is completed, remove the tightening bolts 30, rotate the detachable flange 23 to remove it, and remove the fixed flange 20 and the formwork 11.

[0049] Step 15: Cut off the grouting pipe 16 that extends beyond the inner skin of the structure, and cover the orifice of the grouting pipe 16 with a matching screw cap 31 so that repeated grouting can be achieved by opening the screw cap 31 in the later stage.

[0050] As can be seen from the above, the simultaneous grouting system applicable to the mined - out structure of the present invention has the following effects: 1. Through simultaneous grouting, the void area between the structure and the waterproof layer can be effectively filled, avoiding water seepage caused by voids. Moreover, since the time interval between the grouting operation and the casting of structural concrete is short, the grout and the concrete can be integrated into one, improving the integrity between the structure and the grouting material. At the same time, the grout has good bonding properties and mechanical properties, achieving close contact with the waterproof layer and having no water - channeling passage between them.

[0051] 2. Since the formwork removal is after grouting, it avoids setting up scaffolds for the later backfill grouting operation, improving construction efficiency and saving costs.

[0052] 3. This grouting pipe can be grouted repeatedly. If water seepage is found during the later operation, only need to open the nearby grouting holes to grout again, avoiding the disadvantages of long construction period, high cost, affecting structural safety and great social impact caused by later drilling.

[0053] 4. A water - stop flange 17 is arranged in the middle of the grouting pipe 16, which can meet the waterproof requirements between the grouting pipe 16 and the surrounding concrete.

[0054] In the description of the present invention, it should be understood that the terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counter - clockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0055] In the present invention, unless otherwise clearly specified and defined, the terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0056] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrated examples described herein.

Claims

1. A synchronous grouting system suitable for dark excavation structure, characterized in that: include: A primary support (1), a geotextile buffer layer (2), a waterproof board (3), a template (11) and a grouting device (8); the geotextile buffer layer (2) is laid on the primary support (1); the waterproof board (3) is laid on the geotextile buffer layer (2); a secondary lining (7) is cast between the template (11) and the waterproof board (3); the grouting device (8) is installed on the template (11); one end of the grouting device (8) is in contact with the waterproof board (3) and the other end extends out of the template (11); and after the secondary lining (7) is initially set, grouting is injected into the grouting device (8).

2. A synchronous grouting system suitable for dark excavation structure according to claim 1, characterized in that: The secondary lining (7) is bound with structural main reinforcement (13), structural distribution reinforcement (14) and structural stirrups (15). A plurality of template openings (12) are provided on the template (11). The center of the template opening (12) is consistent with the center of a square formed by the structural main reinforcement (13) and the structural distribution reinforcement (14). The grouting device (8) is installed in the template opening (12).

3. A synchronous grouting system suitable for dark excavation structure according to claim 2, characterized in that: When the template (11) is installed, a longitudinal construction joint (9) and an annular construction joint (10) are formed. The longitudinal spacing and annular spacing of the template openings (12) are set to 4-6m. Template openings (12) are set at both sides of the annular construction joint (10) and at the upper and lower sides of the longitudinal construction joint (9) at a distance of 500mm from the joint.

4. The synchronous grouting system suitable for dark excavation structure according to claim 2 is characterized in that: The grouting device (8) comprises: a fixed flange (20), a detachable flange (23) and a grouting pipe (16); the fixed flange (20) is connected to the template (11); the detachable flange (23) is connected to the outside of the fixed flange (20) via a fastening bolt (30); one end of the grouting pipe (16) is screwed to the neck of the detachable flange (23), and the other end extends into the second lining (7) to contact the waterproof board (3); the detachable flange (23) and the grouting pipe (16) are centrally connected to form a grouting channel.

5. The synchronous grouting system suitable for dark excavation structure according to claim 4 is characterized in that: The fixed flange (20) is arranged in a circular shape, comprising a fixed flange central opening (21) and at least four fixed flange bolt holes (22), and the plurality of fixed flange bolt holes (22) are evenly arranged along the circumferential direction of the fixed flange (20).

6. The synchronous grouting system suitable for dark excavation structure according to claim 5, characterized in that: The removable flange (23) is arranged in a circular shape, and comprises a removable flange panel (26), a removable flange neck (27) and a removable flange neck sleeve (28) which are connected in sequence. A removable flange center opening (24) is arranged through the center of the removable flange (23). The removable flange panel (26) is evenly arranged with at least four removable flange bolt holes (25) along the circumferential direction. The removable flange bolt holes (25) correspond to the fixed flange bolt holes (22) one by one and are connected by fastening bolts (30). The removable flange neck (27) is sleeved in the template opening (12) and the fixed flange center opening (21). The removable flange neck sleeve (28) is connected to the center of the removable flange neck (27) and protrudes from its surface. The thickness of the removable flange neck (27) is equal to the sum of the thickness of the template (11) and the fixed flange (20). The removable flange neck sleeve (28) is provided with an external thread (29).

7. The synchronous grouting system suitable for dark excavation structure according to claim 6, characterized in that: The grouting pipe (16) comprises a water stop flange (17) and a rubber suction cup (18); the annular water stop flange (17) is connected to the middle of the grouting pipe (16); one end of the grouting pipe (16) is provided with an internal thread (19); the internal thread (19) of the grouting pipe (16) is connected to the external thread (29) of the detachable flange neck sleeve (28), and the connection length is adjustable; the other end of the grouting pipe (16) is provided with a rubber suction cup (18), and the rubber suction cup (18) is in contact with the waterproof board (3).

8. The synchronous grouting system suitable for dark excavation structure according to claim 7, characterized in that: The grouting device (8) further comprises a screw cover (31), and after the fixed flange (20), the detachable flange (23) and the template (11) are removed, the screw cover (31) is screwed to the grouting pipe (16).

9. The synchronous grouting system suitable for dark excavation structure according to claim 1, characterized in that: The base surface of the primary support (1) is leveled to a flatness that satisfies D / L≤1 / 8, where D is the maximum depth of the concave portion between two adjacent convex surfaces and L is the shortest distance between two adjacent convex surfaces.

10. The synchronous grouting system suitable for dark excavation structure according to claim 1, characterized in that: The geotextile buffer layer (2) is fixed to the base surface of the primary support (1) by cement nails (4); an iron gasket (5) and a plastic round gasket (6) are arranged between the end of the cement nail (4) and the geotextile buffer layer (2); the center of the plastic round gasket (6) is pressed onto the geotextile buffer layer (2), and a groove for accommodating the iron gasket (5) is formed at the center; protrusions around the plastic round gasket (6) are adapted to protrusions on the waterproof board (3); and the waterproof board (3) is welded to the plastic round gasket (6).

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