Large karst cave invasion section tunnel supporting structure

Abstract

The utility model belongs to the technical field of highway and railway tunnel construction, and particularly relates to a large karst cave invasion section tunnel supporting structure. Comprising a cross beam, a raft plate, a protective arch, a primary support structure, a bottom plate and a lining, the beams are located at the bottom of the tunnel and arranged at intervals in the length direction of the tunnel, one end of each beam crosses the middle line of the tunnel, the other end of each beam extends into the wall of the karst cave, the raft is integrally connected to the top faces of the beams and located within the range of the karst cave, and a backfill layer is arranged from the raft to the bottom face of the karst cave. The primary supporting structure is arranged on the inner wall of the tunnel, the lining is arranged on the primary supporting structure, and the bottom plate is arranged on the bottom face of the tunnel. The protection arch is connected with the part, located in the karst cave, of the primary supporting structure along the tunnel outline, the lower end of the protection arch is connected with a raft, and the upper end is connected with the karst cave wall. Karst is rapidly and efficiently treated in a raft plate, cross beam and backfill mode, the construction efficiency is high, the quality and safety control effect is good, and the construction progress is fast.

Description

Technical Field

[0001] The utility model belongs to the technical field of highway and railway tunnel construction, and in particular relates to a large-scale karst cave invasion section tunnel support structure. Background Art

[0002] During tunnel construction, special geological conditions such as karst caves are often encountered, especially in southwest China, where the patterns and conditions of karst caves are even more complex and varied. Karst caves are underground dissolution phenomena formed by chemical and mechanical damage of surface water and groundwater to soluble rock layers. When karst caves are on one side or below the tunnel construction layer, they are more likely to have an adverse effect on tunnel construction, and large-area karst caves require targeted treatment. Utility Model Content

[0003] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described below.

[0004] The utility model provides the following technical solutions: a large-scale karst cave intrusion section tunnel support structure, including a crossbeam, a raft, a protective arch, an initial support structure, a bottom plate and a lining;

[0005] The crossbeam is located at the bottom of the tunnel and is arranged at intervals along the length of the tunnel. One end of the crossbeam crosses the center line of the tunnel and the other end extends into the wall of the cave. The raft is integrally connected to the top of the crossbeam. The raft is located within the scope of the cave, and the backfill layer is from the raft to the bottom of the cave.

[0006] The initial support structure is arranged on the inner wall of the tunnel, the lining is arranged on the initial support structure, and the bottom plate is arranged on the bottom surface of the tunnel;

[0007] The guard arch is connected to the portion of the initial support structure located in the cave along the tunnel contour, and the lower end of the guard arch is connected to the raft slab, and the upper end is connected to the cave wall.

[0008] Further, the initial support structure includes an initial support steel frame, a steel mesh, a primary sprayed concrete layer and a secondary sprayed concrete layer;

[0009] The initial shotcrete layer is located on the excavation surface of the tunnel. The initial support steel frame is installed on the initial shotcrete layer. The initial support steel frames are arranged at intervals along the length of the tunnel. Steel meshes are laid between the initial support steel frames to cover the initial shotcrete layer. The re-shotcrete layer is joined to the initial shotcrete layer to wrap the initial support steel frame and the steel mesh.

[0010] Furthermore, the initial support steel frame includes several steel frame segments. A locking foot anchor rod group is arranged at the arch foot position of the initial support steel frame outside the cave range and the joint position of two steel frame segments. The casing of the locking foot anchor rod in the locking foot anchor rod group is fixedly connected to the initial support steel frame.

[0011] Furthermore, the locking foot anchor rod group includes a horizontal first locking foot anchor rod, a downwardly inclined second locking foot anchor rod and a third locking foot anchor rod.

[0012] Furthermore, the included angle between the second locking foot anchor rod and the first locking foot anchor rod is 30°, and the included angle between the third locking foot anchor rod and the first locking foot anchor rod is 60°.

[0013] Furthermore, the installation spacing of the initial support steel frames is 0.6m, and two adjacent initial support steel frames are longitudinally connected with steel tie rods, and the circumferential spacing of the steel tie rods is 1m.

[0014] Furthermore, tires are filled between the guard arch and the cave wall.

[0015] Furthermore, the height of the cross beam is 3m, the height of the raft is 1.5m, and the thickness of the arch guard is 2m.

[0016] Furthermore, the lengths of the first locking foot anchor rod, the second locking foot anchor rod and the third locking foot anchor rod are 4.5 m.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] The utility model provides a large-scale karst cave intrusion section tunnel support structure, which adopts a "raft plate + beam + backfill" method to quickly and efficiently deal with karst, has high construction efficiency, good quality and safety control effects, and fast construction progress. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the utility model;

[0020] Figure 2 This is a schematic diagram of the initial support structure;

[0021] Figure 3 This is a schematic diagram of the connection between the initial support steel frames.

[0022] In the figure: 1-tunnel; 2-cave; 3-initial support structure; 4-lining; 5-arch; 6-crossbeam; 7-raft; 8-bottom plate; 9-initial support steel frame; 10-initial sprayed concrete layer; 11-re-sprayed concrete layer; 12-first locking anchor rod; 13-second locking anchor rod; 14-third locking anchor rod; 15-rebar tension rod. DETAILED DESCRIPTION

[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] like Figure 1 As shown: a large-scale karst cave intrusion section tunnel support structure, including cross beam 6, raft 7, arch 5, initial support structure 3, bottom plate 8 and lining 4; cross beam 6 is located at the bottom of the tunnel, cross beam 6 is arranged at intervals along the length direction of the tunnel, one end of cross beam 6 crosses the tunnel center line, and the other end extends into the karst cave wall, raft 7 is integrally connected to the top surface of cross beam 6, raft 7 is located within the karst cave, and the raft 7 to the bottom surface of the karst cave is a backfill layer; initial support structure 3 is arranged on the inner wall of the tunnel, lining 4 is arranged on the initial support structure 3, and bottom plate 8 is arranged on the bottom surface of the tunnel; arch 5 is connected to the part of initial support structure 3 located in the karst cave along the tunnel contour, the lower end of arch 5 is connected to raft 7, and the upper end is connected to the karst cave wall. Tires are filled between arch 5 and the karst cave wall.

[0025] The construction sequence is: construction of beam 6 and raft slab 7, construction of initial support structure 3, construction of base plate 8, construction of lining 4, and construction of arch guard 5.

[0026] The height of the cross beam 6 is 3 m, the height of the raft 7 is 1.5 m, and the thickness of the arch guard 5 is 2 m.

[0027] The cross beam 6 and raft 7 are cast on site. When the concrete is transported into the mold, the temperature of the concrete entering the mold is lowered (the temperature entering the mold is less than 28°C). The concrete is poured in horizontal layers with a layer thickness of no more than 30cm. When the free fall height of the concrete exceeds 2m, a string tube is used to discharge the concrete to prevent concrete segregation.

[0028] like Figure 2 As shown: the initial support structure 3 includes an initial support steel frame 9, a steel mesh, a primary sprayed concrete layer 10 and a secondary sprayed concrete layer 11;

[0029] The primary sprayed concrete layer 10 is located on the excavation surface of the tunnel. The thickness of the primary sprayed concrete layer 10 is 4 cm. The initial support steel frame 9 is installed on the primary sprayed concrete layer 10. The initial support steel frames 9 are arranged at intervals along the length direction of the tunnel. Steel meshes are laid between the initial support steel frames 9 to cover the primary sprayed concrete layer 10. The secondary sprayed concrete layer 11 is joined to the primary sprayed concrete layer 10 to wrap the initial support steel frame 9 and the steel mesh. The total thickness of the primary sprayed concrete layer 10 and the secondary sprayed concrete layer 11 is 30 cm.

[0030] The initial support steel frame 9 adopts I22 steel frame. The initial support steel frame 9 includes several steel frame segments. The arch foot position of the initial support steel frame 9 outside the cave range and the joint position of the two steel frame segments are provided with a locking foot anchor rod group. The sleeve of the locking foot anchor rod in the locking foot anchor rod group is fixedly connected to the initial support steel frame 9.

[0031] The foot locking anchor rod group includes a horizontal first foot locking anchor rod 12, a downwardly inclined second foot locking anchor rod 13 and a third foot locking anchor rod 14. The first foot locking anchor rod 12, the second foot locking anchor rod 13 and the third foot locking anchor rod 14 are φ42 foot locking anchor rods, and the length of the first foot locking anchor rod 12, the second foot locking anchor rod 13 and the third foot locking anchor rod 14 is 4.5m.

[0032] During construction, the angle and direction of the locking anchor rod should be determined in combination with the inclination and strike of the rock formation, the direction of joint development, etc. Generally, the angle between the second locking anchor rod 13 and the first locking anchor rod 12 is 30°, and the angle between the third locking anchor rod 14 and the first locking anchor rod 12 is 60°.

[0033] like Figure 3 As shown: the installation spacing of the initial support steel frames 9 is 0.6m, and two adjacent initial support steel frames 9 are longitudinally connected by steel bar tie rods 15, and the circumferential spacing of the steel bar tie rods 15 is 1m.

[0034] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A large-scale cave intrusion tunnel support structure, characterized by: It includes a cross beam (6), a raft (7), a protective arch (5), an initial support structure (3), a bottom plate (8) and a lining (4); The cross beam (6) is located at the bottom of the tunnel. The cross beams (6) are arranged at intervals along the length direction of the tunnel. One end of the cross beam (6) crosses the center line of the tunnel and the other end extends into the wall of the karst cave. The raft (7) is integrally connected to the top surface of the cross beam (6). The raft (7) is located within the karst cave. The area from the raft (7) to the bottom surface of the karst cave is a backfill layer. The initial support structure (3) is arranged on the inner wall of the tunnel, the lining (4) is arranged on the initial support structure (3), and the bottom plate (8) is arranged on the bottom surface of the tunnel; The guard arch (5) is connected to the portion of the initial support structure (3) located in the karst cave along the tunnel contour; the lower end of the guard arch (5) is connected to the raft (7) and the upper end is connected to the wall of the karst cave.

2. A large-scale cave intrusion tunnel support structure according to claim 1, characterized in that: The initial support structure (3) comprises an initial support steel frame (9), a steel mesh, a primary sprayed concrete layer (10) and a secondary sprayed concrete layer (11); The primary sprayed concrete layer (10) is located on the excavation surface of the tunnel, the primary support steel frame (9) is installed on the primary sprayed concrete layer (10), the primary support steel frames (9) are arranged at intervals along the length direction of the tunnel, steel mesh is laid between the primary support steel frames (9) to cover the primary sprayed concrete layer (10), and the secondary sprayed concrete layer (11) is connected to the primary sprayed concrete layer (10) to wrap the primary support steel frame (9) and the steel mesh.

3. A large-scale karst cave intrusion tunnel support structure according to claim 2, characterized in that: The initial support steel frame (9) comprises a plurality of steel frame segments, and a locking foot anchor rod group is arranged at the arch foot position of the initial support steel frame (9) outside the scope of the karst cave and at the joint position of two steel frame segments, and the sleeve of the locking foot anchor rod in the locking foot anchor rod group is fixedly connected to the initial support steel frame (9).

4. A large-scale cave intrusion tunnel support structure according to claim 3, characterized in that: The foot locking anchor rod group comprises a horizontal first foot locking anchor rod (12), a downwardly inclined second foot locking anchor rod (13), and a third foot locking anchor rod (14).

5. A large-scale karst cave intrusion tunnel support structure according to claim 4, characterized in that: The included angle between the second locking foot anchor rod (13) and the first locking foot anchor rod (12) is 30°, and the included angle between the third locking foot anchor rod (14) and the first locking foot anchor rod (12) is 60°.

6. A large-scale cave intrusion tunnel support structure according to claim 2, characterized in that: The installation spacing of the initial support steel frames (9) is 0.6 m, and two adjacent initial support steel frames (9) are longitudinally connected by steel tie rods (15), and the circumferential spacing of the steel tie rods (15) is 1 m.

7. A large-scale cave intrusion tunnel support structure according to claim 1, characterized in that: A tire is filled between the guard arch (5) and the cave wall.

8. A large-scale karst cave intrusion tunnel support structure according to claim 1, characterized in that: The height of the cross beam (6) is 3 m, the height of the raft (7) is 1.5 m, and the thickness of the arch guard (5) is 2 m.

9. A large-scale cave intrusion tunnel support structure according to claim 5, characterized in that: The lengths of the first locking foot anchor rod (12), the second locking foot anchor rod (13) and the third locking foot anchor rod (14) are 4.5 m.

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