Method and device for preventing cracks in tunnel lining

Abstract

The application relates to the technical field of tunnel lining, in particular to a construction method and device for preventing cracks in tunnel lining, which comprises the following steps: step one, cleaning the impurities adhered to the inner wall of the tunnel, and erecting a supporting framework in the tunnel by using steel bars; step two, installing a buffer arc plate on the top wall inside the tunnel, and fixing the buffer arc plate on the supporting framework; step three, installing cooling water pipes in the gaps of the supporting framework, so that the cooling water pipes extend along the length direction of the tunnel; and step four, installing a supporting formwork at the bottom of the supporting framework, the top end of the supporting formwork is provided with a convex plate, and a grouting hole is reserved on the supporting formwork. The construction method and device for preventing cracks in tunnel lining can reduce the concentrated stress generated at the top end of the arched lining by arranging the buffer arc plate which is a steel plate with elasticity, can adapt to and buffer the extrusion deformation of the concrete at the position, and can avoid cracks caused by stress concentration.

Description

Technical Field

[0001] This invention relates to the field of tunnel lining technology, specifically to a construction method and apparatus for preventing tunnel lining cracks. Background Technology

[0002] Tunnel lining refers to the permanent structure that supports and maintains the long-term stability and durability of a tunnel. Its functions include supporting and maintaining tunnel stability; maintaining the space required for train operation; preventing weathering of the surrounding rock; and mitigating the effects of groundwater. Tunnel lining mainly consists of the arch ring, sidewalls, invert arch, and floor slab. Tunnel lining is divided into primary shotcrete and anchor support and secondary reinforced concrete lining.

[0003] However, due to the large heat generation and temperature rise of the secondary lining, and the significant constraint imposed by the primary support on the secondary lining, the free expansion and contraction of the secondary lining is restricted. This leads to substantial temperature stress within the secondary lining, which often causes cracks after exceeding the tensile strength of the concrete. Furthermore, because the tunnel lining is arched, stress concentration at the top of the arch easily causes cracks when the concrete deforms. Therefore, we propose a construction method and device to prevent cracks in the tunnel lining. Summary of the Invention

[0004] The purpose of this invention is to provide a construction method and apparatus for preventing cracks in tunnel lining, which solves the problems in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A construction method and apparatus for preventing cracks in tunnel lining, comprising the following steps:

[0007] Step 1: Clean the impurities adhering to the inner wall of the tunnel and build a support frame inside the tunnel with steel bars.

[0008] Step 2: Install buffer arc plates on the top wall inside the tunnel and fix the buffer arc plates to the support frame;

[0009] Step 3: Install cooling water pipes in the gaps of the support frame so that the cooling water pipes extend along the length of the tunnel.

[0010] Step 4: Install the support template at the bottom of the support frame. The top of the support template has a protruding plate, and grouting holes are reserved on the support template.

[0011] Step 5: Grout concrete into the support frame through the grouting holes so that the concrete is evenly filled between the tunnel inner wall and the support formwork. After grouting is completed, cooling water is introduced into the cooling water pipe to cool the concrete.

[0012] Step 6: After the concrete has cooled, seal both ends of the cooling water pipe and leave water inside the pipe. Then remove the support formwork to leave a groove at the bottom of the concrete lining.

[0013] Step 7: Install the support components in the groove.

[0014] Preferably, the buffer arc plate is an arched steel plate, and the thickness of the buffer arc plate is between 3mm and 6mm, and it is elastic.

[0015] Preferably, the support component is installed in the following manner:

[0016] First, the supporting arc plate is tightly attached to the inner wall of the groove, and then the supporting arc plate is fixed to the concrete lining with expansion bolts. Then, the first and second pressure-bearing components are installed on the inner wall of the supporting arc plate, ensuring that the first pressure-bearing component is sleeved on the outside of the second pressure-bearing component during the installation process.

[0017] Preferably, a spring is provided between the first pressure-bearing member and the second pressure-bearing member.

[0018] Preferably, the groove is arched, and the shape and material of the supporting arc plate are the same as those of the buffer arc plate.

[0019] Preferably, the groove and the buffer arc plate are not on the same diameter of the tunnel, and the cooling water pipe is a steel pipe.

[0020] Preferably, the construction method further includes the step of filling the gap between the buffer arc plate and the tunnel roof with gravel, which is performed after step six.

[0021] Preferably, the support frame contains a wire mesh, which is arc-shaped and its curvature is adapted to the tunnel. The wire mesh is located in the middle of the concrete lining.

[0022] A device for preventing cracks in tunnel lining includes a supporting arc plate with pre-drilled holes. Two guide strips are fixedly connected to the inner wall of the supporting arc plate. The two guide strips are symmetrically distributed about the center line of the supporting arc plate. Each guide strip has multiple first connecting holes, which are equidistant from each other along the length of the guide strip. A first pressure-bearing member and a second pressure-bearing member are respectively sleeved on the two guide strips. The first pressure-bearing member is sleeved on the second pressure-bearing member. Both the first pressure-bearing member and the second pressure-bearing member have second connecting holes.

[0023] Preferably, a baffle is fixedly connected to one end of the second pressure-bearing member, a clearance opening is provided at one end of the first pressure-bearing member, a cavity is provided inside the first pressure-bearing member, and the end of the baffle away from the second pressure-bearing member is elastically connected to the inner wall of the cavity through a spring. There is a gap between the second pressure-bearing member and the inner wall of the clearance opening, and there is a gap between the baffle and the inner wall of the cavity.

[0024] By employing the above technical solution, the present invention provides a construction method and apparatus for preventing tunnel lining cracks. It possesses at least the following beneficial effects:

[0025] (1) The construction method and device for preventing tunnel lining cracks, by setting up a buffer arc plate, which is an elastic steel plate, can reduce the concentrated stress generated at the top of the arched lining, adapt to and buffer the extrusion deformation of the concrete at this point, and avoid cracks caused by stress concentration.

[0026] (2) The construction method and device for preventing tunnel lining cracks can increase the deformation space at the bottom of the concrete lining by opening a groove, and can increase the strength and support force of the part by installing support components in the groove, thereby achieving the purpose of preventing cracking.

[0027] (3) The construction method and device for preventing tunnel lining cracks can accelerate the cooling rate inside the concrete and reduce the cooling rate between the inside and outside of the concrete by setting up built-in cooling water pipes, thereby reducing the temperature difference and preventing cracks caused by the difference in thermal expansion between the inside and outside of the concrete.

[0028] (4) The construction method and device for preventing tunnel lining cracks can reduce the temperature change inside the concrete by retaining water in the cooling water pipe and further improve the heat preservation and crack prevention capabilities of the concrete by setting steel wire.

[0029] (5) The construction method and device for preventing tunnel lining cracks, by maintaining a gap between the second bearing member and the inner wall of the relief opening, and by maintaining a gap between the baffle and the inner wall of the cavity, allows for a certain relief space between the first bearing member and the second bearing member, which is convenient to adapt to the bending deformation of the supporting arc plate. Attached Figure Description

[0030] The accompanying drawings, which are provided to further illustrate the invention, constitute a part of this application:

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 In this invention Figure 1 Enlarged view of the structure at point A in the middle;

[0033] Figure 3 This is a schematic diagram of the support component in this invention;

[0034] Figure 4 This is a schematic diagram of the guide bar in this invention;

[0035] Figure 5 This is a cross-sectional view of the first pressure-bearing component in this invention.

[0036] In the diagram: 1. Buffer arc plate; 2. Cooling water pipe; 3. Support template; 4. Protruding plate; 51. Support arc plate; 52. Guide strip; 53. First pressure bearing component; 54. Second pressure bearing component; 55. First connecting hole; 56. Cavity; 57. Second connecting hole; 58. Baffle; 59. Spring; 510. Clearance opening. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] Please see Figures 1-5 The present invention provides a technical solution:

[0040] A construction method and apparatus for preventing cracks in tunnel lining, the construction method comprising the following steps:

[0041] Step 1: Clean the impurities adhering to the inner wall of the tunnel and build a support frame inside the tunnel with steel bars. The support frame is made of interlaced steel bars. The specific reinforcement method can be designed according to the size of the tunnel and the material of the concrete grouting to bear the tensile stress of the concrete lining, increase its strength, and improve its crack resistance and collapse resistance.

[0042] Step 2: Install buffer arc plate 1 on the top wall inside the tunnel and fix buffer arc plate 1 to the support frame; the buffer arc plate 1 is an arched steel plate, and the thickness of the buffer arc plate 1 is between 3mm and 6mm, so that it has a certain elasticity, thereby reducing the stress generated at the top of the arch, adapting to and buffering the extrusion deformation of the concrete at this point, and avoiding cracks caused by stress concentration.

[0043] Step 3: Install cooling water pipes 2 in the gaps of the support frame, extending along the length of the tunnel. The built-in cooling water pipes 2 accelerate the cooling rate inside the concrete, reduce the cooling rate between the inside and outside of the concrete, minimize temperature fluctuations, and prevent cracks caused by the difference in thermal expansion between the inside and outside of the concrete. Cooling water pipes 2 are made of steel.

[0044] Step 4: Install the support template 3 at the bottom of the support frame. The top of the support template 3 has a protruding plate 4, and grouting holes are reserved on the support template 3.

[0045] Step 5: Grout concrete into the support frame through the grouting holes, so that the concrete is evenly filled between the tunnel inner wall and the support formwork 3. After grouting is completed, cooling water is introduced into the cooling water pipe 2 to cool the concrete. The flow rate of the cooling water needs to be determined according to the ambient temperature and concrete temperature at the construction site to ensure that the temperature difference between the inside and outside of the concrete is minimized. If necessary, the outside of the concrete needs to be insulated to reduce temperature stress.

[0046] Step Six: After the concrete cools, seal both ends of the cooling water pipe 2 and retain water inside the pipe. Utilize the high specific heat capacity of water to insulate the interior of the lining and reduce temperature fluctuations. Then remove the support formwork 3, leaving a groove at the bottom of the concrete lining. The groove and the buffer arc plate 1 are not on the same diameter as the tunnel.

[0047] Step 7: Fill the gap between the buffer arc plate 1 and the tunnel roof with gravel. Filling with gravel can improve the strength of this area. The gaps between the gravel allow it to maintain a certain deformation capacity, thus adapting to the deformation of the concrete and avoiding stress concentration that could cause cracks.

[0048] Step 8: Install support components in the groove to improve the strength of the groove and increase the structural support.

[0049] In this embodiment, the support components are installed as follows: First, the support arc plate 51 is tightly attached to the inner wall of the groove, and the support arc plate 51 is fixed to the concrete lining with expansion bolts. Then, the first pressure-bearing member 53 and the second pressure-bearing member 54 are installed on the inner wall of the support arc plate 51. During the installation process, the first pressure-bearing member 53 is fitted over the second pressure-bearing member 54. A spring 59 is provided between the first pressure-bearing member 53 and the second pressure-bearing member 54. When the concrete deforms, it will compress the support arc plate 51, causing the first pressure-bearing member 53 and the second pressure-bearing member 54 to move relative to each other, thereby eliminating some stress. By setting the spring 59, the first pressure-bearing member 53 and the second pressure-bearing member 54 can be supported to return to their original position, and the vibration borne by the concrete lining can also be buffered.

[0050] Furthermore, the groove is arched, and the shape and material of the supporting arc plate 51 are the same as those of the buffer arc plate 1.

[0051] Furthermore, the support frame contains a wire mesh, which is arc-shaped and its curvature is adapted to the tunnel. The wire mesh is located in the middle of the concrete lining to enhance the tensile strength of the concrete, thereby achieving the purposes of crack prevention and heat insulation.

[0052] Example 2

[0053] Please see Figures 3-5 A device for preventing cracks in tunnel lining, as described in Embodiment 1, includes a supporting arc plate 51 with pre-drilled holes for fixing it to the concrete lining using expansion bolts. Two guide strips 52 are fixedly connected to the inner wall of the supporting arc plate 51, symmetrically distributed about the centerline of the supporting arc plate 51. Each guide strip 52 has multiple first connecting holes 55, equidistantly spaced along its length. A first pressure-bearing member 53 and a second pressure-bearing member 54 are respectively fitted onto each guide strip 52, with the first pressure-bearing member 53 fitted onto the second pressure-bearing member 54. Both the first pressure-bearing member 53 and the second pressure-bearing member 54 have second connecting holes 57. After aligning the first connecting hole 55 with the second connecting hole 57, the first pressure-bearing component 53 or the second pressure-bearing component 54 can be fixed to the guide strip 52 with bolts, which facilitates the disassembly and assembly of the first pressure-bearing component 53 and the second pressure-bearing component 54. At the same time, the number of the first pressure-bearing component 53 and the second pressure-bearing component 54 can be increased or decreased according to actual needs. When the supporting force of the supporting arc plate 51 decreases in the later stage, the first pressure-bearing component 53 and the second pressure-bearing component 54 can be added to improve the supporting force.

[0054] In this embodiment, a baffle 58 is fixedly connected to one end of the second pressure-bearing member 54, and a clearance opening 510 is provided at one end of the first pressure-bearing member 53. A cavity 56 is provided inside the first pressure-bearing member 53. The end of the baffle 58 away from the second pressure-bearing member 54 is elastically connected to the inner wall of the cavity 56 through a spring 59. There is a gap between the second pressure-bearing member 54 and the inner wall of the clearance opening 510, and there is a gap between the baffle 58 and the inner wall of the cavity 56. After the first pressure-bearing member 53 and the second pressure-bearing member 54 are installed, the second pressure-bearing member 54 does not contact the clearance opening 510, and the baffle 58 does not contact the cavity 56. This allows clearance space to be reserved between the first pressure-bearing member 53 and the second pressure-bearing member 54, which is convenient to accommodate the bending deformation of the supporting arc plate 51.

[0055] When using a device to prevent tunnel lining cracks, firstly, the supporting arc plate 51 is tightly attached to the inner wall of the groove, and the supporting arc plate 51 is fixed to the concrete lining by expansion bolts. Then, the first bearing member 53 and the second bearing member 54 are respectively sleeved on the two guide strips 52. When the second connecting hole 57 on the first bearing member 53 and the second bearing member 54 is aligned with the first connecting hole 55 on the guide strip 52, the first bearing member 53 and the second bearing member 54 are fixed to the guide strip 52 by bolts.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A construction method for preventing cracks in tunnel lining, characterized in that: Includes the following steps: Step 1: Clean the impurities adhering to the inner wall of the tunnel and build a support frame inside the tunnel with steel bars. Step 2: Install the buffer arc plate (1) on the top wall inside the tunnel and fix the buffer arc plate (1) to the support frame; Step 3: Install cooling water pipes (2) in the gaps of the support frame so that the cooling water pipes (2) extend along the length of the tunnel; Step 4: Install the support template (3) at the bottom of the support frame. The top of the support template (3) has a protruding plate (4), and grouting holes are reserved on the support template (3). Step 5: Grout concrete into the support frame through the grouting hole so that the concrete is evenly filled between the tunnel inner wall and the support formwork (3). After the grouting is completed, cooling water is introduced into the cooling water pipe (2) to cool the concrete. Step 6: After the concrete cools, seal both ends of the cooling water pipe (2) and retain water in the cooling water pipe (2). Then remove the support formwork (3) to leave a groove at the bottom of the concrete lining. Step 7: Install the support components inside the groove; The buffer arc plate (1) is an arched steel plate, and the thickness of the buffer arc plate (1) is between 3mm and 6mm, and it is elastic; The installation method of the support component is as follows: First, the support arc plate (51) is tightly attached to the inner wall of the groove, and the support arc plate (51) is fixed to the concrete lining by expansion bolts. Then, the first pressure-bearing component (53) and the second pressure-bearing component (54) are installed on the inner wall of the support arc plate (51). During the installation process, the first pressure-bearing component (53) is sleeved on the outside of the second pressure-bearing component (54).

2. The construction method for preventing tunnel lining cracks according to claim 1, characterized in that: A spring (59) is provided between the first pressure-bearing member (53) and the second pressure-bearing member (54).

3. The construction method for preventing tunnel lining cracks according to claim 1, characterized in that: The groove is arched, and the shape and material of the supporting arc plate (51) are the same as those of the buffer arc plate (1).

4. The construction method for preventing tunnel lining cracks according to claim 1, characterized in that: The groove and the buffer arc plate (1) are not on the same diameter of the tunnel, and the cooling water pipe (2) is a steel pipe.

5. The construction method for preventing tunnel lining cracks according to claim 1, characterized in that: The construction method also includes the step of filling the gap between the buffer arc plate (1) and the tunnel top wall with gravel, which is after step six.

6. The construction method for preventing tunnel lining cracks according to claim 1, characterized in that: The support frame contains a wire mesh, which is arc-shaped and its curvature is adapted to the tunnel. The wire mesh is located in the middle of the concrete lining.

7. A device for preventing cracks in tunnel lining, characterized in that: The system includes a supporting arc plate (51) with pre-drilled holes. Two guide strips (52) are fixedly connected to the inner wall of the supporting arc plate (51). The two guide strips (52) are symmetrically distributed about the center line of the supporting arc plate (51). Each of the two guide strips (52) has multiple first connecting holes (55). The multiple first connecting holes (55) are evenly distributed in a straight line along the length of the guide strip (52). A first pressure-bearing member (53) and a second pressure-bearing member (54) are respectively sleeved on the two guide strips (52). The first pressure-bearing member (53) is sleeved on the second pressure-bearing member (54). Both the first pressure-bearing member (53) and the second pressure-bearing member (54) have second connecting holes (57).

8. The device for preventing tunnel lining cracks according to claim 7, characterized in that: One end of the second pressure-bearing member (54) is fixedly connected to a baffle (58), one end of the first pressure-bearing member (53) is provided with a relief opening (510), and a cavity (56) is provided inside the first pressure-bearing member (53). The end of the baffle (58) away from the second pressure-bearing member (54) is elastically connected to the inner wall of the cavity (56) through a spring (59). There is a gap between the second pressure-bearing member (54) and the inner wall of the relief opening (510), and there is a gap between the baffle (58) and the inner wall of the cavity (56).

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