Tunnel bentonite anti-seepage structure

Abstract

The invention relates to the technical field of tunnel engineering seepage prevention, in particular to a tunnel bentonite seepage prevention structure. The anti-seepage structure comprises an open-cut tunnel anti-seepage structure and a new Austrian composite tunnel anti-seepage structure. The open-cut tunnel anti-seepage structure comprises an open-cut tunnel inverted arch bottom plate anti-seepage structure, an open-cut tunnel vertical wall anti-seepage structure and an open-cut tunnel vault anti-seepage structure. The novel Austrian-method composite tunnel anti-seepage structure comprises a novel Austrian-method tunnel inverted arch bottom plate anti-seepage structure, a novel Austrian-method tunnel vertical wall anti-seepage structure and a novel Austrian-method tunnel vault anti-seepage structure. According to the technical scheme, the problems that in the prior art, a waterproof roll or a waterproof plate cannot be tightly bonded with a base layer, large-area water mixing is caused, and water seepage, drainage, maintenance and management cost increase are caused are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-seepage for tunnel engineering, and particularly to a tunnel bentonite anti-seepage structure. Background Art

[0002] At present, most underground tunnel projects adopt the anti-seepage technology of waterproof coiled materials and waterproof boards. This technology cannot be closely bonded to the base layer, and a gap is formed between the two. Therefore, most underground tunnels have factors of large-area water cross-flow, resulting in leakage of underground tunnels and a large amount of drainage costs, causing serious increases in personnel and costs for tunnel management.

[0003] In view of the problems existing in the above-mentioned prior art, it is very necessary to research and design a new type of tunnel bentonite anti-seepage structure to overcome the problems existing in the prior art. Summary of the Invention

[0004] In view of the technical problems that the waterproof coiled material or waterproof board proposed in the above prior art cannot be closely bonded to the base layer, resulting in large-area water cross-flow, increased water seepage, drainage, and maintenance management costs, a tunnel bentonite anti-seepage structure is provided. The present invention mainly adds bentonite between the tunnel wall and the base layer, and utilizes its water accumulation effect to achieve the overall anti-seepage effect of the material and the structure, and realizes the permanent anti-seepage effect of the underground tunnel.

[0005] The technical means adopted by the present invention are as follows:

[0006] A tunnel bentonite anti-seepage structure includes: an open-cut tunnel anti-seepage structure and a New Austrian Tunneling Method composite tunnel anti-seepage structure;

[0007] Further, the open-cut tunnel anti-seepage structure includes: an open-cut tunnel invert floor anti-seepage structure, an open-cut tunnel vertical wall anti-seepage structure, and an open-cut tunnel arch top anti-seepage structure;

[0008] Further, the New Austrian Tunneling Method composite tunnel anti-seepage structure includes: a New Austrian Tunneling Method tunnel invert floor anti-seepage structure, a New Austrian Tunneling Method tunnel vertical wall anti-seepage structure, and a New Austrian Tunneling Method tunnel arch top anti-seepage structure.

[0009] Further, the open-cut tunnel invert floor anti-seepage structure from bottom to top is successively: a natural base layer, a gravel and bentonite graded bearing anti-seepage body, a 100-mm-thick concrete cushion, a tunnel invert structural floor, and a tunnel vehicle roadway structure layer;

[0010] Further, the open-cut tunnel vertical wall anti-seepage structure from outside to inside is successively: a precast reinforced concrete protective board, a bentonite anti-seepage layer, and a tunnel inner wall structure; first, the tunnel inner wall structure is constructed, then the precast reinforced concrete protective board is installed, a bentonite protective layer is filled between the precast reinforced concrete protective board and the tunnel inner wall structure, and then the natural base layer between the precast reinforced concrete protective boards on both sides of the tunnel is gradually backfilled with plain soil and tamped;

[0011] Further, the anti-seepage structure of the open-cut tunnel vault from bottom to top is as follows: the external wall structure of the tunnel vault, longitudinal granite ribs, bentonite paste anti-seepage layer, fiberglass square grid, 30-mm-thick mortar protective layer, and reinforced concrete fixed protection board; first, construct the external wall structure of the tunnel vault, then install the longitudinal granite ribs, and fill the bentonite paste anti-seepage layer between the longitudinal granite ribs; set the fiberglass square grid outside the bentonite paste anti-seepage layer, construct the 30-mm-thick mortar protective layer outside the fiberglass square grid, set the reinforced concrete fixed protection board outside the 30-mm-thick mortar protective layer, and finally backfill and tamp the plain soil outside the reinforced concrete fixed protection board.

[0012] Further, the graded aggregate anti-seepage body of gravel and bentonite is an anti-seepage body graded from 200 - 500 mm graded gravel and bentonite.

[0013] Further, the anti-seepage structure of the invert floor of the New Austrian Tunneling Method tunnel from bottom to top is as follows: natural base course, graded aggregate anti-seepage body of gravel and bentonite, 100-mm-thick concrete cushion, the structural floor of the tunnel invert, and the tunnel carriageway structure layer.

[0014] Further, the anti-seepage structure of the vertical wall of the New Austrian Tunneling Method tunnel from outside to inside is as follows: tunnel geological surrounding rock, the reinforced concrete layer of the primary lining of the tunnel, bentonite paste anti-seepage layer, non-removable formwork, PVA bentonite water stop strip, and the vertical wall of the tunnel reinforced concrete structure; first, install the truss, then construct the reinforced concrete layer of the primary lining of the tunnel outside the tunnel geological surrounding rock, install the non-removable formwork on the truss, fill the thick bentonite paste anti-seepage layer between the non-removable formwork and the reinforced concrete layer of the primary lining of the tunnel, and finally construct the vertical wall of the tunnel reinforced concrete structure outside the non-removable formwork; before constructing the vertical wall of the tunnel reinforced concrete structure, assemble the PVA bentonite water stop strip outside the non-removable formwork.

[0015] Further, the anti-seepage structure of the vault of the New Austrian Tunneling Method tunnel from top to bottom is as follows: tunnel geological surrounding rock, the reinforced concrete layer of the primary lining of the tunnel, bentonite paste anti-seepage layer, non-removable formwork, PVA bentonite water stop strip, and the external wall structure of the tunnel vault; first, set the primary lining anchor bolts and steel mesh on the tunnel geological surrounding rock, build the truss, construct the reinforced concrete layer of the primary lining of the tunnel, install the upper non-removable formwork, and embed the spherical check valve grouting pipe on the non-removable formwork, assemble the PVA bentonite water stop strip outside the non-removable formwork, construct the secondary reinforced concrete external wall of the tunnel vault outside the non-removable formwork, and finally pour the bentonite paste anti-seepage layer between the non-removable formwork and the reinforced concrete layer of the primary lining of the tunnel through the spherical check valve grouting pipe.

[0016] Further, the thickness of the bentonite paste anti-seepage layer ≥ 50 mm.

[0017] Further, there are multiple spherical check valve grouting pipes, and the spacing ≤ 6 m.

[0018] Furthermore, the PVA bentonite waterstop strip is arranged outside the non-removable formwork in a vertical arrangement.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. For the tunnel bentonite anti-seepage structure provided by the present invention, by arranging the PVA bentonite waterstop strip outside the non-removable formwork, secondary waterproofing and anti-seepage are carried out.

[0021] 2. For the tunnel bentonite anti-seepage structure provided by the present invention, by arranging the non-removable formwork for the construction of the initial lining reinforced concrete layer and the bentonite layer of the tunnel, the removal of the formwork is avoided, the working procedures are saved, the labor intensity is reduced, the construction efficiency is improved, and at the same time, the strength of the tunnel wall is increased, etc.

[0022] 3. For the tunnel bentonite anti-seepage structure provided by the present invention, by arranging the bentonite anti-seepage layer, the absorption and anti-seepage of tunnel seepage water are realized, and various subsequent cumbersome matters such as water cross-flow, maintenance, and management are avoided.

[0023] 4. For the tunnel bentonite anti-seepage structure provided by the present invention, by forming an integral water-repellent structure with the tunnel structure by bentonite, a water-free environment is achieved in the tunnel mining space.

[0024] In summary, the application of the technical solution of the present invention solves the problems in the prior art that the waterproof coiled material or waterproof board cannot be closely bonded to the base layer, resulting in large-area water cross-flow, increased costs for water seepage, drainage, maintenance, and management, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a schematic structural diagram of the anti-seepage structure of the open-cut tunnel of the present invention;

[0027] Figure 2 It is an enlarged schematic diagram of the anti-seepage structure of the invert floor of the open-cut tunnel of the present invention;

[0028] Figure 3 It is an enlarged schematic diagram of the anti-seepage structure of the vertical wall of the open-cut tunnel of the present invention;

[0029] Figure 4 It is an enlarged schematic diagram of the anti-seepage structure of the arch top of the open-cut tunnel of the present invention;

[0030] Figure 5Schematic structural diagram of the waterproof and seepage prevention structure of the New Austrian Tunneling Method composite tunnel of the present invention;

[0031] Figure 6 Enlarged schematic diagram of the waterproof and seepage prevention structure of the invert floor of the New Austrian Tunneling Method tunnel of the present invention;

[0032] Figure 7 Enlarged schematic diagram of the waterproof and seepage prevention structure of the vertical wall of the New Austrian Tunneling Method tunnel of the present invention;

[0033] Figure 8 Enlarged schematic diagram of the waterproof and seepage prevention structure of the vault of the New Austrian Tunneling Method tunnel of the present invention.

[0034] In the figure: 1. Natural base layer; 2. Gravel and bentonite graded bearing and waterproof layer; 3. 100mm thick concrete cushion; 4. Invert floor structure of the tunnel; 5. Tunnel vehicle road structure layer; 6. Prefabricated reinforced concrete protection board; 7. Bentonite waterproof layer; 8. Tunnel inner wall structure; 9. Tunnel inner wall structure; 10. Plain soil; 11. Reinforced concrete fixed protection board; 12. 30mm thick mortar protection layer; 13. Glass fiber square grid; 14. Bentonite paste waterproof layer; 15. Longitudinal granite rib; 16. Tunnel vault outer wall structure; 17. Tunnel geological surrounding rock; 18. Initial lining reinforced concrete layer of the tunnel; 19. Formwork without removal; 20. PVA bentonite water stop strip; 21. Ball check valve grouting pipe. Detailed implementation manners

[0035] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0036] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of the described features, steps, operations, devices, components and / or their combinations.

[0038] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of convenience in description, the dimensions of the various parts shown in the drawings are not drawn in accordance with actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not require further discussion in subsequent drawings.

[0039] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. are usually based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. Without contrary statements, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as limiting the protection scope of the present invention: the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0040] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above", etc. can be used here to describe the spatial positional relationships of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the drawings for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned as "below other devices or structures" or "beneath other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0041] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of distinguishing the corresponding components. Without additional statements, the above words have no special meanings. Therefore, it should not be construed as limiting the protection scope of the present invention.

[0042] Embodiment 1

[0043] As Figure 1-2 shown, the present invention provides a tunnel bentonite anti-seepage structure, including: an open-cut tunnel anti-seepage structure and a New Austrian Tunneling Method composite tunnel anti-seepage structure;

[0044] The open-cut tunnel anti-seepage structure includes: an open-cut tunnel invert floor anti-seepage structure, an open-cut tunnel vertical wall anti-seepage structure, and an open-cut tunnel arch top anti-seepage structure;

[0045] The New Austrian Tunneling Method composite tunnel anti-seepage structure includes: a New Austrian Tunneling Method tunnel invert floor anti-seepage structure, a New Austrian Tunneling Method tunnel vertical wall anti-seepage structure, and a New Austrian Tunneling Method tunnel arch top anti-seepage structure.

[0046] The open-cut tunnel invert floor anti-seepage structure, from bottom to top, is successively: a natural base layer 1, a graded aggregate bearing and anti-seepage body of gravel and bentonite 2, a 100-mm-thick concrete cushion layer 3, a tunnel invert structural floor 4, and a tunnel vehicle road structural layer 5;

[0047] The open-cut tunnel vertical wall anti-seepage structure, from outside to inside, is successively: a precast reinforced concrete protection board 6, a bentonite anti-seepage layer 7, and a tunnel inner wall structure 8; First, the tunnel inner wall structure 8 is constructed, then the precast reinforced concrete protection board 6 is installed, a bentonite protection layer 7 is filled between the precast reinforced concrete protection board 6 and the tunnel inner wall structure 8, and then plain soil 10 is gradually backfilled and tamped between the precast reinforced concrete protection boards 6 on both sides of the tunnel and the natural base layer 1;

[0048] The open-cut tunnel arch top anti-seepage structure, from bottom to top, is successively: a tunnel arch top outer wall structure 16, longitudinal granite rib strips 15, a bentonite paste anti-seepage layer 14, a fiberglass square grid 13, a 30-mm-thick mortar protection layer 12, and a reinforced concrete fixed protection board 11; First, the tunnel arch top outer wall structure 16 is constructed, then the longitudinal granite rib strips 15 are installed, and a bentonite paste anti-seepage layer 14 is filled between the longitudinal granite rib strips 15; A fiberglass square grid 13 is arranged outside the bentonite paste anti-seepage layer 14, a 30-mm-thick mortar protection layer 12 is constructed outside the fiberglass square grid 13, a reinforced concrete fixed protection board 11 is arranged outside the 30-mm-thick mortar protection layer 12, and finally plain soil 10 is backfilled and tamped outside the reinforced concrete fixed protection board 11.

[0049] The graded aggregate bearing and anti-seepage body of gravel and bentonite 2 is an anti-seepage body formed by grading 200 - 500-mm gravel and bentonite.

[0050] The New Austrian Tunneling Method tunnel invert floor anti-seepage structure, from bottom to top, is successively: a natural base layer 1, a graded aggregate bearing and anti-seepage body of gravel and bentonite 2, a 100-mm-thick concrete cushion layer 3, a tunnel invert structural floor 4, and a tunnel vehicle road structural layer 5;

[0051] The anti-seepage structure of the vertical wall of the New Austrian Tunneling Method tunnel, from the outside to the inside on the right side, is successively: tunnel geological surrounding rock 17, tunnel primary lining reinforced concrete layer 18, bentonite paste anti-seepage layer 14, non-removable formwork 19, PVA bentonite water stop strip 20, and the vertical wall 9 of the tunnel reinforced concrete structure; first, the truss is installed, then the tunnel primary lining reinforced concrete layer 18 is constructed outside the tunnel geological surrounding rock 17, the non-removable formwork 19 is installed on the truss, the thick bentonite paste anti-seepage layer 14 is filled between the non-removable formwork 19 and the tunnel primary lining reinforced concrete layer 18, and finally the vertical wall 9 of the tunnel reinforced concrete structure is constructed outside the non-removable formwork 19; before the construction of the vertical wall 9 of the tunnel reinforced concrete structure, the PVA bentonite water stop strip 20 is assembled outside the non-removable formwork 19;

[0052] The anti-seepage structure of the arch crown of the New Austrian Tunneling Method tunnel, from top to bottom, is successively: tunnel geological surrounding rock 17, tunnel primary lining reinforced concrete layer 18, bentonite paste anti-seepage layer 14, non-removable formwork 19, PVA bentonite water stop strip 20, and the outer wall structure 16 of the tunnel arch crown; first, primary lining anchor bolts and steel meshes are set on the tunnel geological surrounding rock 17, the truss is built, the tunnel primary lining reinforced concrete layer 18 is constructed, the upper non-removable formwork 19 is installed, and the spherical check valve grouting pipe 21 is embedded on the non-removable formwork 19. The PVA bentonite water stop strip 20 is assembled outside the non-removable formwork 19, and the secondary arch crown reinforced concrete outer wall 16 of the tunnel is constructed outside the non-removable formwork 19. Finally, the bentonite paste anti-seepage layer 14 is poured between the non-removable formwork 19 and the tunnel primary lining reinforced concrete layer 18 through the spherical check valve grouting pipe 21.

[0053] The thickness of the bentonite paste anti-seepage layer 14 ≥ 50 mm.

[0054] There are multiple spherical check valve grouting pipes 21, and the spacing ≤ 6 m.

[0055] The PVA bentonite water stop strip 20 is arranged outside the non-removable formwork 19 in a vertical arrangement form.

[0056] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tunnel bentonite anti-seepage structure, characterized in that: The tunnel bentonite anti-seepage structure includes: an open-cut tunnel anti-seepage structure and a New Austrian Tunneling Method composite tunnel anti-seepage structure; The open-cut tunnel anti-seepage structure includes: an open-cut tunnel inverted arch bottom anti-seepage structure, an open-cut tunnel vertical wall anti-seepage structure, and an open-cut tunnel arch top anti-seepage structure; The New Austrian Tunneling Method composite tunnel anti-seepage structure includes: a New Austrian Tunneling Method tunnel inverted arch bottom anti-seepage structure, a New Austrian Tunneling Method tunnel vertical wall anti-seepage structure, and a New Austrian Tunneling Method tunnel arch top anti-seepage structure.

2. The tunnel bentonite anti-seepage structure according to claim 1, characterized in that: The open-cut tunnel inverted arch bottom anti-seepage structure, from bottom to top, is successively: a natural base layer (1), a gravel and bentonite graded bearing anti-seepage body (2), a 100-mm-thick concrete cushion layer (3), a tunnel inverted arch structural bottom plate (4), and a tunnel vehicle roadway structure layer (5); The open-cut tunnel vertical wall anti-seepage structure, from outside to inside, is successively: a precast reinforced concrete protection board (6), a bentonite anti-seepage layer (7), and a tunnel inner wall structure (8); First, the tunnel inner wall structure (8) is constructed, then the precast reinforced concrete protection board (6) is installed, a bentonite protection layer (7) is filled between the precast reinforced concrete protection board (6) and the tunnel inner wall structure (8), and then plain soil (10) is gradually backfilled and tamped between the precast reinforced concrete protection boards (6) on both sides of the tunnel and the natural base layer (1); The open-cut tunnel arch top anti-seepage structure, from bottom to top, is successively: a tunnel arch top outer wall structure (16), longitudinal granite rib strips (15), a bentonite paste anti-seepage layer (14), a fiberglass square grid (13), a 30-mm-thick mortar protection layer (12), and a reinforced concrete fixed protection board (11); First, the tunnel arch top outer wall structure (16) is constructed, then the longitudinal granite rib strips (15) are installed, and a bentonite paste anti-seepage layer (14) is filled between the longitudinal granite rib strips (15); A fiberglass square grid (13) is arranged outside the bentonite paste anti-seepage layer (14), a 30-mm-thick mortar protection layer (12) is constructed outside the fiberglass square grid (13), a reinforced concrete fixed protection board (11) is arranged outside the 30-mm-thick mortar protection layer (12), and finally plain soil (10) is backfilled and tamped outside the reinforced concrete fixed protection board (11).

3. The tunnel bentonite anti-seepage structure according to claim 2, characterized in that: The gravel and bentonite graded bearing anti-seepage body (2) is an anti-seepage body formed by grading 200 - 500 mm graded gravel and bentonite.

4. The tunnel bentonite anti-seepage structure according to claim 1, characterized in that: The New Austrian Tunneling Method tunnel inverted arch bottom anti-seepage structure, from bottom to top, is successively: a natural base layer (1), a gravel and bentonite graded bearing anti-seepage body (2), a 100-mm-thick concrete cushion layer (3), a tunnel inverted arch structural bottom plate (4), and a tunnel vehicle roadway structure layer (5); The anti-seepage structure of the vertical wall of the New Austrian Tunneling Method tunnel from the outside to the inside in sequence is: tunnel geological surrounding rock (17), tunnel primary lining reinforced concrete layer (18), bentonite paste anti-seepage layer (14), non-removable formwork (19), PVA bentonite water stop strip (20), and tunnel reinforced concrete structure vertical wall (9); first, install the truss, then construct the tunnel primary lining reinforced concrete layer (18) outside the tunnel geological surrounding rock (17), install the non-removable formwork (19) on the truss, fill the thick bentonite paste anti-seepage layer (14) between the non-removable formwork (19) and the tunnel primary lining reinforced concrete layer (18), and finally construct the tunnel reinforced concrete structure vertical wall (9) outside the non-removable formwork (19); before constructing the tunnel reinforced concrete structure vertical wall (9), assemble the PVA bentonite water stop strip (20) outside the non-removable formwork (19). The anti-seepage structure of the arch crown of the New Austrian Tunneling Method tunnel from top to bottom in sequence is: tunnel geological surrounding rock (17), tunnel primary lining reinforced concrete layer (18), bentonite paste anti-seepage layer (14), non-removable formwork (19), PVA bentonite water stop strip (20), and tunnel arch crown outer wall structure (16); first, set the primary lining anchor bolts and steel mesh on the tunnel geological surrounding rock (17), build the truss, construct the tunnel primary lining reinforced concrete layer (18), install the upper non-removable formwork (19), embed the spherical check valve grouting pipe (21) on the non-removable formwork (19), assemble the PVA bentonite water stop strip (20) outside the non-removable formwork (19), construct the tunnel secondary arch crown reinforced concrete outer wall (16) outside the non-removable formwork (19), and finally pour the bentonite paste anti-seepage layer (14) between the non-removable formwork (19) and the tunnel primary lining reinforced concrete layer (18) through the spherical check valve grouting pipe (21).

5. The tunnel bentonite anti-seepage structure according to claim 4, wherein: The thickness of the bentonite paste anti-seepage layer (14) ≥ 50 mm.

6. The tunnel bentonite anti-seepage structure according to claim 4, wherein: There are multiple spherical check valve grouting pipes (21), and the spacing ≤ 6 m.

7. The tunnel bentonite anti-seepage structure according to claim 4, wherein: The PVA bentonite water stop strip (20) is arranged outside the non-removable formwork (19) in a vertical arrangement form.

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