Dovetail section tunnel face plugging structure and construction method

Abstract

The invention belongs to the technical field of construction of end walls of ultra-large-span loess tunnels, and particularly relates to a dovetail section tunnel face plugging structure and a construction method. Comprising a blocking structure outside the excavation range of two small holes in a large tunnel hole and a supporting structure in the excavation range of the small holes. The blocking structure sequentially comprises a drainage system, a steel supporting structure, a reinforcing anchor rod, a first reinforcing mesh and a first sprayed concrete layer from inside to outside in the tunneling direction of the tunnel. The supporting structure comprises a second sprayed concrete layer, anchor rods and a second reinforcing mesh; the forked tail section tunnel face plugging structure is easy to construct, the plugging structure in a large tunnel hole is easy and convenient to install, all structural layers are high in connectivity and good in integrity, and the supporting effect is remarkable; the drainage system is convenient to install and can meet the drainage requirement under the water-rich stratum; the reinforcing anchor rod can be suitable for unfavorable geology reinforcement construction; the construction method of the forked tail section tunnel face blocking structure is convenient and fast in construction, the blocking structure is safe and reliable, and a hole is easy and convenient to break.

Description

Technical Field

[0001] The invention belongs to the technical field of super-large-span loess tunnel end wall construction, and specifically relates to a dovetail section face blocking structure and a construction method. Background Art

[0002] During the construction of the swallowtail tunnel, the blocking structure is mainly reflected in the end wall where the single hole is changed into double holes (multiple holes). The traditional construction method is reinforced concrete structure blocking, which has many disadvantages such as long construction time, waste of labor, difficulty in breaking the hole, slow double hole entry, etc. It can no longer meet the requirements of the entire construction market at this stage for energy conservation and environmental protection, safety and quality, and progress target construction. Summary of the invention

[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 hereinafter.

[0004] The present invention provides the following technical solutions: a dovetail section face plugging structure, comprising a plugging structure outside the excavation range of two small holes in a large tunnel hole and a supporting structure within the excavation range of the small holes;

[0005] From inside to outside along the tunnel excavation direction, the blocking structure includes drainage system, steel support structure, reinforcing anchor rods, first steel mesh and first shotcrete layer;

[0006] The supporting structure includes a second shotcrete layer, anchor rods and a second steel mesh.

[0007] Furthermore, the steel support structure includes an outer support ring on the contour line of the large tunnel hole and an inner support ring on the contour line of the small tunnel hole. The outer support ring and the inner support ring are connected by a steel frame, and the outer support ring, the inner support ring and the steel frame are located in the same plane.

[0008] Furthermore, the steel frame includes a main vertical support, a transverse support and a secondary vertical support. The main vertical support is between the two small holes. A group of locking foot anchor pipes are installed at the bottom of the main vertical support. The locking foot anchor pipes are welded to the main vertical support with L-shaped steel bars. The secondary vertical supports are symmetrically arranged on both sides of the main vertical support. A complete transverse support is installed in each width section of the steel frame, and the transverse support is connected to the main vertical support, the secondary vertical support, the outer support ring or the inner support ring.

[0009] Furthermore, the reinforcing anchor rod is a mortar anchor rod, the length of the reinforcing anchor rod is 4m, the installation spacing is 1.2m*1.2m, the medicine bag of the reinforcing anchor rod is 20-30S rapid consolidation material, the anchor rod head of the reinforcing anchor rod is an expansion shell anchor rod head, the tail of the reinforcing anchor rod is connected to the L-shaped steel bar through a threaded sleeve, and the L-shaped steel bar is welded to the steel support structure.

[0010] Furthermore, the anchor rods are drug pack anchor rods, the installation spacing is 1.2m*1.2m, and the anchor rods are arranged in a plum blossom shape.

[0011] Furthermore, the drainage system includes vertical drainage blind pipes and horizontal drainage blind pipes. The vertical drainage blind pipes are φ90 double-wall perforated corrugated pipes, and the installation spacing of the vertical drainage blind pipes is 1.5m. The horizontal drainage blind pipes are φ50 single-wall perforated corrugated pipes, and the installation spacing of the horizontal drainage blind pipes is 3m. The horizontal drainage blind pipes are introduced into the vertical drainage blind pipes through connecting parts, and a bend is set at 1m at the bottom of the vertical drainage blind pipe to lead out water.

[0012] Furthermore, the outer support ring, the inner support ring and the main vertical support are formed by splicing I-beams, steel plates are welded at both ends of the I-beams, and the I-beams are connected by bolts on the steel plates.

[0013] A construction method for a dovetail section tunnel face plugging structure comprises the following steps:

[0014] Install the drainage system. When installing the drainage system, wrap the outside of the vertical drainage blind pipe and the horizontal drainage blind pipe with geotextile. The vertical drainage blind pipe and the horizontal drainage blind pipe are fixed on the tunnel face with steel U-shaped clips. Install the horizontal drainage blind pipe first, and then install the vertical drainage blind pipe;

[0015] Install the steel support structure. When installing the steel support structure, first install the main vertical brace and the secondary vertical brace, and then install the horizontal brace;

[0016] The shotcrete layer is constructed, including the first shotcrete layer and the second shotcrete layer. The shotcrete layer is constructed using a wet spraying robot, and is sprayed sequentially from bottom to top in sections and layers, with a spraying thickness of 25 cm.

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

[0018] The sealing structure of the dovetail section face is easy to construct, the sealing structure in the large tunnel hole is easy to install, the structural layers have strong connectivity, good integrity, and significant support effect; the drainage system is easy to install and can meet the drainage requirements below the water-rich stratum; the reinforced anchor rods can be used for reinforcement construction in poor geology; the construction method of the dovetail section face sealing structure is convenient, fast, the sealing structure is safe and reliable, and the opening is easy to break. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the steel support structure;

[0020] Figure 2 This is a side view of the blocking structure.

[0021] In the figure: 1-large tunnel hole; 2-small hole; 3-drainage system; 4-steel support structure; 4.1-outer support ring; 4.2-inner support ring; 4.3-cross brace; 4.4-main vertical brace; 4.5-secondary vertical brace; 5-reinforcement anchor rod; 6-first steel mesh; 7-first shotcrete layer. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the embodiments of the present invention 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 present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Example 1

[0024] like Figure 1 , Figure 2 As shown: a dovetail section face blocking structure, including a blocking structure outside the excavation range of two small holes 2 in a large tunnel hole 1 and a supporting structure within the excavation range of the small holes; along the tunnel excavation direction from inside to outside, the blocking structure includes a drainage system 3, a steel support structure 4, a reinforcing anchor rod 5, a first steel mesh 6 and a first shotcrete layer 7 in sequence; the supporting structure includes a second shotcrete layer, anchor rods and a second steel mesh.

[0025] The steel support structure 4 includes an outer support ring 4.1 on the outline of the large tunnel hole and an inner support ring 4.2 on the outline of the small tunnel hole. The outer support ring 4.1 and the inner support ring 4.2 are connected by a steel frame. The outer support ring 4.1, the inner support ring 4.2 and the steel frame are located in the same plane.

[0026] The steel frame includes a main vertical support 4.4, a transverse support 4.3 and a secondary vertical support 4.5. The main vertical support 4.4 is between the two small holes 2. A group of locking foot anchor pipes is installed at the bottom of the main vertical support 4.4. The group of locking foot anchor pipes includes 2 4m long φ42 locking foot anchor pipes. The locking foot anchor pipes are connected to the main vertical support 4.4 by welding L-shaped steel bars. The locking foot anchor pipes are connected to the main vertical support 4.4 at a distance of 60cm from the bottom. The secondary vertical supports 4.5 are symmetrically arranged on both sides of the main vertical support 4.4. The spacing between the secondary vertical supports 4.5 and the secondary vertical supports 4.5 and the main vertical support 4.4 is 2m. A complete transverse support 4.3 is installed in each width section of the steel frame. The transverse support 4.3 is connected to the main vertical support 4.4, the secondary vertical support 4.5, the outer support ring 4.1 or the inner support ring 4.2, and the spacing between the transverse supports 4.3 is 1.2m.

[0027] The outer support ring 4.1, the inner support ring 4.2 and the main vertical support 4.4 are formed by splicing I-beams, steel plates are welded at both ends of the I-beams, and the I-beams are connected by bolts on the steel plates.

[0028] The secondary vertical brace 4.5 and the transverse brace 4.3 adopt a grid steel frame, which is made of main reinforcement (φ22 steel bars), cross-shaped reinforcement (φ14 steel bars) and 80*80 angle steel. The transverse brace 4.3 is embedded in the flange plates on both sides of the I-beam and is welded to the I-beam.

[0029] The reinforcing anchor rod 5 is a mortar anchor rod. The length of the reinforcing anchor rod 5 is 4m, the installation spacing is 1.2m*1.2m, the medicine bag of the reinforcing anchor rod 5 is 20-30S fast consolidation material, the anchor rod head of the reinforcing anchor rod 5 is an expansion shell anchor rod head, and the tail of the reinforcing anchor rod 5 is connected to the L-shaped steel bar through a threaded sleeve, and the L-shaped steel bar is welded to the steel support structure.

[0030] The drilling direction of the reinforcing anchor rod 5 should be as perpendicular as possible to the surrounding rock and the main structural surface of the rock formation. The reinforcing anchor rod 5 should be driven in and the rod body of the reinforcing anchor rod 5 should be rotated to fully stir the medicine bag until the reinforcing anchor rod 5 reaches the bottom of the hole and slurry flows out of the hole mouth.

[0031] The anchor rods are drug pack anchor rods with an installation spacing of 1.2m*1.2m and are arranged in a plum blossom shape.

[0032] The drainage system 3 includes vertical drainage blind pipes and horizontal drainage blind pipes. The vertical drainage blind pipes are φ90 double-wall perforated corrugated pipes, and the installation spacing of the vertical drainage blind pipes is 1.5m. The horizontal drainage blind pipes are φ50 single-wall perforated corrugated pipes, and the installation spacing of the horizontal drainage blind pipes is 3m. The horizontal drainage blind pipes are introduced into the vertical drainage blind pipes through connectors, and a bend is set at 1m at the bottom of the vertical drainage blind pipe to lead out water.

[0033] Example 2

[0034] A construction method of a dovetail segment tunnel face plugging structure, used for constructing the dovetail segment tunnel face plugging structure of Example 1, comprises the following steps:

[0035] Install drainage system 3. When installing drainage system 3, geotextile is wrapped outside the vertical drainage blind pipe and the horizontal drainage blind pipe. The vertical drainage blind pipe and the horizontal drainage blind pipe are fixed on the tunnel face with steel bar U-shaped clips. The horizontal drainage blind pipe is installed first, and then the vertical drainage blind pipe is installed.

[0036] Install the steel support structure. When installing the steel support structure, first install the main vertical brace 4.4 and the secondary vertical brace 4.5, and then install the horizontal brace 4.3;

[0037] The sprayed concrete layer is constructed, including the first sprayed concrete layer 7 and the second sprayed concrete layer. The sprayed concrete layer is constructed using a wet spraying manipulator, and is sprayed in sections and layers from bottom to top in sequence, with a spraying thickness of 25 cm.

[0038] 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 rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dovetail section face plugging structure, characterized in that: It includes a blocking structure outside the excavation range of two small holes (2) in the large tunnel hole (1) and a supporting structure within the excavation range of the small holes; From inside to outside along the tunnel excavation direction, the blocking structure includes a drainage system (3), a steel support structure (4), a reinforcing anchor rod (5), a first steel mesh (6) and a first shotcrete layer (7) in sequence; The supporting structure includes a second shotcrete layer, anchor rods and a second steel mesh.

2. The dovetail section tunnel face plugging structure according to claim 1 is characterized in that: The steel support structure (4) comprises an outer support ring (4.1) on the outline of a large tunnel hole and an inner support ring (4.2) on the outline of a small tunnel hole; the outer support ring (4.1) and the inner support ring (4.2) are connected by a steel frame; and the outer support ring (4.1), the inner support ring (4.2) and the steel frame are located in the same plane.

3. The dovetail segment tunnel face blocking structure according to claim 2 is characterized in that: The steel frame comprises a main vertical support (4.4), a transverse support (4.3) and a secondary vertical support (4.5), wherein the main vertical support (4.4) is located between the two small holes (2), a group of locking foot anchor pipes are installed at the bottom of the main vertical support (4.4), and L-shaped steel bars are welded between the locking foot anchor pipes and the main vertical support (4.4), and the secondary vertical support (4.5) is symmetrically arranged on both sides of the main vertical support (4.4), and a complete transverse support (4.3) is installed in each width section of the steel frame, and the transverse support (4.3) is connected to the main vertical support (4.4), the secondary vertical support (4.5), the outer support ring (4.1) or the inner support ring (4.2).

4. The dovetail segment tunnel face plugging structure according to claim 3 is characterized in that: The reinforcing anchor rod (5) is a mortar anchor rod, the length of the reinforcing anchor rod (5) is 4m, the installation spacing is 1.2m*1.2m, the medicine bag of the reinforcing anchor rod (5) is a 20-30S fast consolidation material, the anchor rod head of the reinforcing anchor rod (5) is an expansion shell anchor rod head, and the tail of the reinforcing anchor rod (5) is connected to the L-shaped steel bar through a threaded sleeve, and the L-shaped steel bar is welded to the steel support structure.

5. The dovetail segment tunnel face plugging structure according to claim 1 is characterized in that: The anchor rods are drug bag anchor rods, the installation spacing is 1.2m*1.2m, and the anchor rods are arranged in a plum blossom shape.

6. The dovetail segment tunnel face plugging structure according to claim 4 is characterized in that: The drainage system (3) comprises a vertical drainage blind pipe and a horizontal drainage blind pipe. The vertical drainage blind pipe is a φ90 double-wall perforated corrugated pipe. The installation spacing of the vertical drainage blind pipe is 1.5m. The horizontal drainage blind pipe is a φ50 single-wall perforated corrugated pipe. The installation spacing of the horizontal drainage blind pipe is 3m. The horizontal drainage blind pipe is introduced into the vertical drainage blind pipe through a connecting piece. A bend is arranged at 1m from the bottom of the vertical drainage blind pipe to lead out water.

7. The dovetail segment tunnel face plugging structure according to claim 3 is characterized by: The outer support ring (4.1), the inner support ring (4.2) and the main vertical support (4.4) are formed by splicing I-beams, steel plates are welded at both ends of the I-beams, and the I-beams are connected by bolts on the steel plates.

8. A construction method for a dovetail section tunnel face plugging structure, used for constructing the dovetail section tunnel face plugging structure according to claim 6, characterized in that: Including the following processes: Install the drainage system (3). When installing the drainage system (3), the outer sides of the vertical drainage blind pipe and the horizontal drainage blind pipe are wrapped with geotextile. The vertical drainage blind pipe and the horizontal drainage blind pipe are fixed on the tunnel face using steel U-shaped clips. The horizontal drainage blind pipe is installed first, and then the vertical drainage blind pipe is installed. Install the steel support structure. When installing the steel support structure, first install the main vertical brace (4.4) and the secondary vertical brace (4.5), and then install the horizontal brace (4.3); The sprayed concrete layer is constructed, including a first sprayed concrete layer (7) and a second sprayed concrete layer. The sprayed concrete layer is constructed using a wet spraying manipulator, and is sprayed in sections and layers from bottom to top in sequence, with a spraying thickness of 25 cm.

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