Composite structure lining for shield tunnel and construction method

Abstract

The invention provides a composite structure lining for a shield tunnel and a construction method. The composite structure lining comprises a primary support, a prefabricated inverted arch is arranged at the bottom of the primary support, and a main body structure is arranged on the prefabricated inverted arch; the primary support comprises a concrete layer, and the concrete layer is anchored on the surrounding rock through an anchor rod; the prefabricated inverted arch comprises a drainage ditch and a pipeline ditch; the main body structure is composed of an inner side steel plate, an outer side steel plate and reinforced concrete between the inner side steel plate and the outer side steel plate, a foam geopolymer backfill layer is arranged between the main body structure and the primary support, and a permeable pipe network communicated with the drainage ditch is arranged in the foam geopolymer backfill layer; the method further comprises the following steps that shield tunnel primary supporting and anchor rod construction are conducted; assembling a prefabricated inverted arch and constructing a waterproof layer; mounting a main body structure steel plate and weaving and binding a reinforcing mesh; pouring concrete and constructing a backfill layer; and removing the steel pipe frame and entering the next cycle. One-time formwork erecting and two-time pouring are achieved, construction procedures are reduced, and the construction progress is accelerated.

Description

Technical Field

[0001] The invention relates to the technical field of shield tunnel construction, and in particular to a composite structure lining for a shield tunnel and a construction method. Background Art

[0002] The shield method is a fully mechanized construction method in the dark excavation method. It pushes the shield machine into the ground, supports the surrounding rock with the shield shell and segments to prevent collapse into the tunnel, and uses a cutting device to excavate the soil in front of the excavation face. The soil is transported out of the cave by the excavation machinery, and is pressurized and pushed forward at the rear by jacks. The precast concrete segments are assembled to form a mechanized construction method of the tunnel structure.

[0003] In shield tunnels with ground explosion resistance requirements, backfill layers are usually set above the bottom plate. Foamed geopolymer is a commonly used backfill layer material. Foamed geopolymer is made by mixing metakaolin (MK), alkali activator, deionized water, foaming materials (hydrogen peroxide (H2O2) foaming agent, physical foaming agent, silicon carbide (SiC) foaming agent, EPS foam), admixtures (calcium hydroxide, fly ash, alumina fiber, polyacrylamide) in a certain ratio.

[0004] The foam geopolymer backfill layer is usually reserved for 0.6m-0.8m. If the foam geopolymer backfill layer is constructed first, there will be a gap between the outer steel plate of the main structure and the backfill layer, and dense backfilling cannot be performed. In addition, two formwork operations are required, which is labor-intensive and has high construction costs. Summary of the invention

[0005] The object of the present invention is to provide a composite structure lining and a construction method for a shield tunnel to solve the above technical problems.

[0006] The present invention provides a composite structure lining for a shield tunnel, comprising an initial support installed on surrounding rock, a prefabricated inverted arch being arranged at the bottom of the initial support, and a main structure being arranged on the prefabricated inverted arch;

[0007] The initial support includes a concrete layer, and the concrete layer is anchored on the surrounding rock by anchor rods;

[0008] The prefabricated invert includes a drainage ditch and a pipeline ditch;

[0009] The main structure is composed of an inner steel plate, an outer steel plate and reinforced concrete therebetween. A foam geopolymer backfill layer is provided between the main structure and the initial support. A permeable pipe network connected to the drainage ditch is provided in the foam geopolymer backfill layer.

[0010] Furthermore, the concrete layer is anchored on the surrounding rock through large deformation adaptive anchor rods and common mortar anchor rods, and the large deformation adaptive anchor rods and the common mortar anchor rods are evenly spaced.

[0011] Furthermore, a waterproof board is laid between the initial support and the foamed geopolymer backfill layer, and the permeable pipe network is arranged below the waterproof board.

[0012] Furthermore, the permeable pipe network includes an annular permeable pipe and a longitudinal permeable pipe, the connection between the annular permeable pipe and the longitudinal permeable pipe is connected through a cross joint, and the bottom end of the annular permeable pipe is connected to the drainage ditch through a drainage pipe.

[0013] Furthermore, the annular water-permeable pipe and the longitudinal water-permeable pipe are both spring water-permeable pipes.

[0014] Furthermore, the inner steel plate and the outer steel plate are connected via a bracing rod penetrating the main structure.

[0015] Furthermore, an end plate for sealing the reinforced concrete is provided between the inner steel plate and the outer steel plate.

[0016] Furthermore, a double-layer slurry pipe assembly is provided on the outer steel plate for respectively pouring the concrete of the main structure and the foamed geopolymer backfill layer, and the double-layer slurry pipe assembly includes a first slurry pipe and a second slurry pipe. The first slurry pipe passes through the outer steel plate and extends between the outer steel plate and the inner steel plate, and the second slurry pipe passes through the main structure and extends between the outer steel plate and the initial support.

[0017] Furthermore, water-swellable rubber strips are provided between adjacent prefabricated inverts.

[0018] The present invention also provides a construction method for a composite structure lining of a shield tunnel, comprising the following steps:

[0019] S1, initial support and anchor construction of shield tunnel: according to the designed anchor position, large deformation adaptive anchors and ordinary mortar anchors are applied, and initial support shotcrete is used. When the surrounding rock conditions are poor, steel arch frames need to be set up and then shotcrete is used;

[0020] S2, prefabricated invert assembly and waterproof layer construction: the prefabricated invert is assembled by mechanical lifting, a concrete cushion is set under the prefabricated invert, and water-expandable rubber strips are set at the corresponding positions of the drainage ditch and the pipeline ditch between the prefabricated inverts to ensure the sealing and position correspondence between the drainage ditch and the pipeline ditch; a waterproof board is set on the initial support surface, and a permeable pipe network is set under the waterproof board. The circumferential permeable pipe is laid along the circumference of the section, and the longitudinal permeable pipe is laid along the longitudinal direction of the shield tunnel. A cross joint is set at the horizontal and vertical connection between the circumferential permeable pipe and the longitudinal permeable pipe, and the circumferential permeable pipe is finally connected to the drainage pipe of the prefabricated invert;

[0021] S3, installation of main structure steel plates and weaving of steel mesh: first, set up steel pipe racks and work platforms on the prefabricated invert, assemble the first ring of inner steel plates from the inside out, weave the first ring of steel mesh, and then splice the first ring of outer steel plates. Set bracing rods between the inner and outer steel plates; repeat this cycle in the longitudinal direction of the shield tunnel, and set double-layer grouting pipes at the same time to close the end plates on both sides;

[0022] S4, pouring concrete and backfilling construction; first pour the main structure self-compacting concrete, and close the first grouting pipe; after the concrete reaches 75% of the design strength, pour the foam geopolymer backfilling material, and close the second grouting pipe;

[0023] S5, dismantle the steel pipe rack and enter the next cycle.

[0024] The invention effectively alleviates pressure-bearing explosion and reduces structural deformation; the method of the invention realizes one-time mold erection and two-time pouring, reduces construction procedures, speeds up construction progress and reduces construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 It is a schematic diagram of the initial support and prefabricated invert of the present invention;

[0028] Figure 3 It is a schematic diagram of the installation of the main structure of the present invention;

[0029] Figure 4 It is a flow chart of the construction method of the present invention;

[0030] Description of reference numerals:

[0031] In the figure: 1-concrete layer, 11-large deformation adaptive anchor rod, 12-ordinary mortar anchor rod, 13-waterproof board, 2-foamed geopolymer backfill layer, 21-annular permeable pipe, 22-longitudinal permeable pipe, 3-prefabricated invert, 31-drainage ditch, 32-pipeline ditch, 33-drainage pipe, 41-reinforced concrete, 42-inner steel plate, 43-outer steel plate, 44-supporting rod, 51-first slurry pipe, 52-second slurry pipe, 6-steel pipe rack; DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. 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 circumstances.

[0035] Example 1

[0036] like Figure 1-Figure 3 As shown:

[0037] A composite structure lining for a shield tunnel comprises an initial support, a prefabricated invert 3 is arranged on the driving road surface at the bottom of the initial support, and a main structure is arranged on the prefabricated invert 3.

[0038] The initial support includes a concrete layer 1, which is anchored on the surrounding rock through large deformation adaptive anchor rods 11 and ordinary mortar anchor rods 12. The large deformation adaptive anchor rods 11 and ordinary mortar anchor rods 12 are evenly spaced.

[0039] When the surrounding rock conditions are poor, a steel arch can be set up before spraying concrete.

[0040] A waterproof board 13 is laid on the inner side of the initial support.

[0041] A water-permeable pipe network is arranged below the waterproof plate 13 , and the water-permeable pipe network includes an annular water-permeable pipe 21 and a longitudinal water-permeable pipe 22 . The connection between the annular water-permeable pipe 21 and the longitudinal water-permeable pipe 22 is connected through a cross joint.

[0042] The annular water-permeable pipe 21 and the longitudinal water-permeable pipe 22 are both spring water-permeable pipes.

[0043] The annular water-permeable pipe 21 is laid circumferentially along the section and evenly arranged at intervals of 6m along the longitudinal direction of the shield tunnel; the longitudinal water-permeable pipe 22 is laid along the longitudinal direction of the shield tunnel, with 5 pipes set on the section, 1 pipe on the arch crown, 2 pipes symmetrically set on the arch waist, and 2 pipes symmetrically set on the arch foot.

[0044] The prefabricated invert 3 comprises a drainage ditch 31 and a pipeline ditch 32 . The drainage ditch 31 is located in the middle, and the pipeline ditch 32 is symmetrically arranged at upper positions on both sides of the drainage ditch 31 .

[0045] Drain pipes 33 penetrating the prefabricated inverted arch 3 and extending to the outside are arranged on both sides of the drainage ditch 31 , and the drainage pipes 33 are communicated with the bottom end of the annular permeable pipe 21 .

[0046] A concrete cushion is arranged at the bottom of the prefabricated inverted arch 3 when it is assembled on site, and water-expandable rubber strips are arranged at corresponding positions of the drainage ditch 31 and the pipeline ditch 32 between adjacent prefabricated inverted arches 3 to ensure sealing and corresponding positions between the drainage ditch 31 and the pipeline ditch 32.

[0047] The main structure is composed of an inner steel plate 42, an outer steel plate 43 and reinforced concrete 41 therebetween. The outer steel plate 43 is 5 mm thick and the inner steel plate 42 is 20 mm thick. In this embodiment, the reinforced concrete 41 is self-compacting concrete, which can self-level to a compact state without vibration.

[0048] The inner steel plate and the outer steel plate are connected by a bracing rod 44 that runs through the main structure, ensuring that the steel plates on both sides are stable and do not deform when pouring concrete.

[0049] An end plate for sealing the reinforced concrete 41 is provided between the inner steel plate and the outer steel plate.

[0050] A double-layer slurry pipe assembly is provided on the outer steel plate for respectively pouring the concrete of the main structure and the foamed geopolymer backfill layer 2.

[0051] In this embodiment, there are three groups of double-layer slurry discharge pipe assemblies, one group is set in the middle and the top of both sides of the section, and additional ones can be added when necessary to meet the concrete discharge height.

[0052] The double-layer lower pulp pipe assembly includes a first lower pulp pipe 51 and a second lower pulp pipe 52 .

[0053] The first slurry lower pipe 51 penetrates the outer steel plate and extends between the outer steel plate and the inner steel plate. The reinforced concrete 41 is poured between the outer steel plate and the inner steel plate through the first slurry lower pipe 51 .

[0054] The second slurry pipe 52 penetrates the main structure and extends to between the outer steel plate and the initial support. The foamed geopolymer backfill layer 2 is poured between the main structure and the initial support through the second slurry pipe 52.

[0055] The foamed geopolymer backfill layer 2 covers the permeable pipe network.

[0056] A construction method for a composite structure lining of a shield tunnel comprises the following steps:

[0057] S1, initial support and anchor bolt construction of shield tunnel: according to the designed anchor bolt position, large deformation adaptive anchor bolt 11 and ordinary mortar anchor bolt 12 are applied, initial support spraying concrete is applied, and when the surrounding rock conditions are poor, steel arch frame needs to be installed and then spraying concrete is applied;

[0058] S2, assembly of prefabricated inverted arch 3 and construction of waterproof layer: the prefabricated inverted arch 3 is assembled by mechanical lifting, a 100mm thick C20 concrete cushion is set under the prefabricated inverted arch 3, water-expandable rubber strips are set at corresponding positions of the drainage ditch 31 and the pipeline ditch 32 between the prefabricated inverted arches 3 to ensure the sealing and position correspondence between the drainage ditch 31 and the pipeline ditch 32; a waterproof board 13 is set on the initial support surface, a permeable pipe network is set under the waterproof board 13, annular permeable pipes 21 are set along the circumference of the section, and are evenly arranged at intervals of 6m along the longitudinal direction of the shield tunnel, and longitudinal permeable pipes 22 are laid along the longitudinal direction of the shield tunnel, 5 pipes are set on the section, 1 pipe on the arch top, 2 pipes are symmetrically set on the arch waist, and 2 pipes are symmetrically set on the arch foot, a cross joint is set at the horizontal and vertical connection between the annular permeable pipe 21 and the longitudinal permeable pipe 22, and the annular permeable pipe 21 is finally connected to the drainage pipe 33 of the prefabricated inverted arch 3;

[0059] S3, installation of main structure steel plates and weaving of steel mesh: first, set up a steel pipe rack 6 and a work platform on the prefabricated invert 3, assemble the first ring inner steel plate 42 with a width of 1m from the inside to the outside, weave the first ring steel mesh, and then splice the first ring outer steel plate 43 with a width of 1m, and set a bracing rod 44 between the inner steel plate 42 and the outer steel plate; follow this cycle in the longitudinal direction of the shield tunnel, install 12m as a construction section, and set a double-layer grouting pipe at the same time, and close the end plates on both sides;

[0060] S4, pouring concrete and backfill layer 2 construction; first pour the main structure self-compacting concrete, and close the first slurry pipe 51; after the concrete reaches 75% of the design strength, pour the foamed geopolymer backfill layer 2 material, and close the second slurry pipe 52;

[0061] S5, dismantle the steel pipe rack 6 and enter the next cycle.

[0062] The present invention effectively reduces pressure-bearing explosion and structural deformation; realizes one-time formwork erection and two-time pouring, effectively replacing the traditional construction method of two-time formwork erection and two-time pouring, reducing construction procedures, speeding up construction progress, and reducing construction costs.

[0063] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite structure lining for a shield tunnel, characterized in that It comprises an initial support installed on the surrounding rock, wherein a prefabricated inverted arch is arranged at the bottom of the initial support, and a main structure is arranged on the prefabricated inverted arch; The initial support includes a concrete layer, and the concrete layer is anchored on the surrounding rock by anchor rods; The prefabricated invert includes a drainage ditch and a pipeline ditch; The main structure is composed of an inner steel plate, an outer steel plate and reinforced concrete therebetween. A foam geopolymer backfill layer is provided between the main structure and the initial support. A permeable pipe network connected to the drainage ditch is provided in the foam geopolymer backfill layer.

2. The composite structure lining for shield tunnel according to claim 1, characterized in that: The concrete layer is anchored on the surrounding rock through large deformation adaptive anchor rods and common mortar anchor rods, and the large deformation adaptive anchor rods and the common mortar anchor rods are evenly spaced.

3. The composite structure lining for a shield tunnel according to claim 1, characterized in that: A waterproof board is laid between the initial support and the foamed geopolymer backfill layer, and the permeable pipe network is arranged below the waterproof board.

4. The composite structure lining for a shield tunnel according to claim 1, characterized in that: The permeable pipe network includes an annular permeable pipe and a longitudinal permeable pipe. The connection between the annular permeable pipe and the longitudinal permeable pipe is connected through a cross joint. The bottom end of the annular permeable pipe is connected to the drainage ditch through a drainage pipe.

5. The composite structure lining for a shield tunnel according to claim 4, characterized in that: The annular water-permeable pipe and the longitudinal water-permeable pipe are both spring water-permeable pipes.

6. The composite structure lining for a shield tunnel according to claim 1, characterized in that: The inner steel plate and the outer steel plate are connected via a supporting rod that penetrates the main structure.

7. The composite structure lining for a shield tunnel according to claim 1, characterized in that: An end plate for sealing the reinforced concrete is arranged between the inner steel plate and the outer steel plate.

8. The composite structure lining for a shield tunnel according to claim 1, characterized in that: The outer steel plate is provided with a double-layer slurry pipe assembly for respectively pouring the concrete of the main structure and the foamed polymer backfill layer, and the double-layer slurry pipe assembly includes a first slurry pipe and a second slurry pipe. The first slurry pipe passes through the outer steel plate and extends between the outer steel plate and the inner steel plate, and the second slurry pipe passes through the main structure and extends between the outer steel plate and the initial support.

9. The composite structure lining for a shield tunnel according to claim 1, characterized in that: Water-swellable rubber strips are arranged between adjacent prefabricated inverts.

10. A construction method for composite structure lining of a shield tunnel, characterized in that: The following steps are involved: S1, initial support and anchor construction of shield tunnel: according to the designed anchor position, large deformation adaptive anchors and ordinary mortar anchors are applied, and initial support shotcrete is used. When the surrounding rock conditions are poor, steel arch frames need to be set up and then shotcrete is used; S2, prefabricated invert assembly and waterproof layer construction: the prefabricated invert is assembled by mechanical lifting, a concrete cushion is set under the prefabricated invert, and water-expandable rubber strips are set at the corresponding positions of the drainage ditch and the pipeline ditch between the prefabricated inverts to ensure the sealing and position correspondence between the drainage ditch and the pipeline ditch; a waterproof board is set on the initial support surface, and a permeable pipe network is set under the waterproof board. The circumferential permeable pipe is laid along the circumference of the section, and the longitudinal permeable pipe is laid along the longitudinal direction of the shield tunnel. A cross joint is set at the horizontal and vertical connection between the circumferential permeable pipe and the longitudinal permeable pipe, and the circumferential permeable pipe is finally connected to the drainage pipe of the prefabricated invert; S3, installation of main structure steel plates and weaving of steel mesh: first, set up steel pipe racks and work platforms on the prefabricated invert, assemble the first ring of inner steel plates from the inside out, weave the first ring of steel mesh, and then splice the first ring of outer steel plates. Set bracing rods between the inner and outer steel plates; repeat this cycle in the longitudinal direction of the shield tunnel, and set double-layer grouting pipes at the same time to close the end plates on both sides; S4, pouring concrete and backfilling construction; first pour the main structure self-compacting concrete, and close the first grouting pipe; after the concrete reaches 75% of the design strength, pour the foam geopolymer backfilling material, and close the second grouting pipe; S5, dismantle the steel pipe rack and enter the next cycle.

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