A flexible tunnel joint structure applicable to active faults and its installation method

Abstract

The present invention provides a flexible joint structure for a tunnel applicable to active faults and an installation method thereof. The flexible joint structure includes a primary support, a waterproof board, and a secondary lining sequentially arranged downward from the surrounding rock. The secondary lining includes a pre-cast secondary lining section and a post-cast secondary lining section. A flexible joint capable of three-dimensional deformation self-adaptation is provided between the pre-cast secondary lining section and the post-cast secondary lining section. The flexible joint is configured to be waterproof. A water receiving box is provided below the flexible joint. Through the three-dimensional deformation self-adaptation of the flexible joint, the present invention can be applicable to three-dimensional dislocation under a major earthquake. The flexible joint itself has a good waterproof function, and through the waterproof board and the water receiving box, the waterproof ability of the tunnel flexible joint structure is better.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering. Specifically, it relates to a flexible tunnel joint structure applicable to active faults and an installation method thereof. Background Art

[0002] With the rapid development of the transportation industry, more and more tunnels are facing the area of crossing active fault zones. The influence of active fault zones on tunnel structures is mainly reflected in: First, the influence of fault activity. For tunnel structures with a long service life, the slip and dislocation of faults will have a significant impact on the safety of tunnel support structures. Second, tunnels passing through faults or fault fracture zones will be severely damaged during earthquakes. The lining near the fault will have large lateral and longitudinal displacements in the plane perpendicular to the tunnel axis.

[0003] Currently, for tunnel projects passing through active faults, the anti-fracture design mainly includes optimizing the lining section profile, overexcavation design, articulated design, and isolation and energy dissipation design, etc.

[0004] After retrieval, it is found that the Chinese invention patent with the application publication number CN108119161A discloses a precast flexible joint structure for a tunnel lining across an active fault zone and a tunnel primary lining structure. This structure includes the initial tunnel support, waterproof board, secondary lining section, and flexible joint; the secondary lining section includes the first section of the secondary lining and the second section of the secondary lining. The flexible joint is used to connect the first section of the secondary lining and the second section of the secondary lining, and is used to bear the differential displacement, dislocation displacement, and damage of strong seismic energy between the formation and the structure under strong vibration. Under dislocation and strong earthquake, the connection ends of the secondary lining and the flexible joint can freely expand and contract longitudinally and deform circumferentially. This structure actively guides the differential displacement, dislocation displacement, and strong seismic energy between the formation and the structure to the flexible joint between tunnel segments, achieving the anti-seismic and shock-absorbing purpose of the tunnel structure across faults and large active fault zones at the cost of damaging the joint, providing safety guarantees for the safety of personnel, machines, and equipment, as well as post-earthquake emergency rescue, and at the same time enabling the joint to be repaired in time after the earthquake. This flexible joint realizes the function of guiding the differential displacement, dislocation displacement, and strong seismic energy between the formation and the structure to the tunnel segments by reserving a steel sleeve in a foam concrete, and the steel sleeve penetrates into the secondary linings at both ends. However, the present invention still has the following problems:

[0005] 1. The ability of this joint to adapt to circumferential deformation is limited. When there is a large circumferential deformation, under the action of the steel sleeve, it is easy to damage the secondary lining structures at both ends.

[0006] 2. The longitudinal deformation adaptability of this joint is poor. It can only adapt to longitudinal extrusion deformation. When there is longitudinal opening deformation, the joint cannot adapt, the foam concrete will be pulled apart, and the joint function will fail.

[0007] 3. It is difficult to ensure the waterproof and sealing performance of the joint, and it is easy to have water leakage at the joint position. Summary of the Invention

[0008] Aiming at the defects in the prior art, the purpose of the present invention is to provide a tunnel flexible joint structure applicable to active fractures and its installation method.

[0009] The present invention is realized through the following technical solutions:

[0010] According to one aspect of the present invention, there is provided a tunnel flexible joint structure applicable to active fracture zones, including: primary support, waterproof board, and secondary lining arranged successively downward from the surrounding rock; the secondary lining includes a pre-cast secondary lining section and a post-cast secondary lining section, and a flexible joint capable of three-dimensional deformation adaptation is provided between the pre-cast secondary lining section and the post-cast secondary lining section. The flexible joint is configured to be waterproof; a water receiving box is provided below the flexible joint.

[0011] Further, the flexible joint includes a telescopic folding main body portion, and a plurality of connecting portions for extending into the secondary lining are provided at both ends of the folding main body portion. The plurality of connecting portions are arranged circumferentially along the flexible joint.

[0012] Furthermore, the included angle between the connecting portion and the horizontal line where the secondary lining is located is 30 - 60 degrees.

[0013] Further, the length of the folding main body portion is 30 - 100 cm.

[0014] Further, the projection distance of the connecting portion on the horizontal line where the secondary lining is located is more than 10 cm.

[0015] Further, the flexible joint is made of rubber material.

[0016] Further, both ends of the flexible joint are respectively connected to the secondary lining through secondary lining end templates. The secondary lining end templates sleeve-press the ends of the flexible joint to fix the flexible joint and form an integral structure between the flexible joint and the secondary lining.

[0017] Further, the primary support uses foam concrete.

[0018] Further, the secondary lining uses concrete.

[0019] According to another aspect of the present invention, there is provided an installation method for the above-mentioned tunnel flexible joint structure applicable to active fractures, including:

[0020] Construct the primary support of the tunnel;

[0021] Lay a waterproof board below the primary support;

[0022] Fix one end of the flexible joint using the end formwork of the secondary lining, and pour it together with the concrete. Construct the secondary lining of the first-poured section under the waterproof board.

[0023] Use the end formwork of the secondary lining to fix the other end of the flexible joint, and pour the secondary lining of the later-poured section, so that the flexible joint is connected as a whole with the secondary linings at both ends of the shock-absorbing joint.

[0024] Install a water receiving box under the flexible joint.

[0025] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0026] 1. The tunnel flexible joint structure applicable to active fault zones and its installation method of the present invention can adapt to the three-dimensional dislocation under large earthquakes through the three-dimensional deformation self-adaptation of the flexible joint.

[0027] 2. For the tunnel flexible joint structure applicable to active fault zones of the present invention, the flexible joint itself has good waterproof function, and through the waterproof board and the water receiving box, the waterproof ability of the tunnel flexible joint structure is better.

[0028] 3. The installation method of the tunnel flexible joint structure applicable to active fault zones of the present invention is simple, reducing the construction complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:

[0030] Figure 1 It is a schematic structural diagram of the tunnel flexible joint structure applicable to active fault zones in the embodiment of the present invention;

[0031] Figure 2 It is a schematic structural diagram of the connection part of the flexible joint in the embodiment of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the end formwork of the secondary lining in the embodiment of the present invention;

[0033] Figure 4 It is a schematic overall diagram after tunnel construction;

[0034] In the figure: 1 is the surrounding rock, 2 is the primary support, 3 is the waterproof board, 4 is the secondary lining of the first-poured section, 5 is the secondary lining of the later-poured section, 6 is the flexible joint, 61 is the foldable main part, 62 is the connecting part, 7 is the water receiving box, and 8 is the end formwork of the secondary lining. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention. In the description of the embodiments of the present invention, it should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here.

[0036] An embodiment of the present invention provides a tunnel flexible joint structure suitable for an active fault zone. Referring to Figure 1 , the tunnel flexible joint structure includes: a primary support 2, a waterproof board 3, and a secondary lining sequentially arranged downward from the surrounding rock 1; the secondary lining includes a first-poured section secondary lining 4 and a second-poured section secondary lining 5, and a flexible joint 6 capable of three-dimensional deformation adaptation is provided between the first-poured section secondary lining 4 and the second-poured section secondary lining 5. The flexible joint 6 is configured to be waterproof; a water receiving box 7 is provided below the flexible joint 6, and the waterproof board 3 and the water receiving box 7 can further improve the waterproof performance of the structure.

[0037] To enable the flexible joint 6 to adapt to three-dimensional deformation, the flexible joint 6 is made of an elastic material. Referring to Figure 2 , in some preferred embodiments, the flexible joint 6 includes a collapsible main body portion 61 that can be telescoped. The collapsible main body portion 61 realizes buffer displacement through telescoping (expanding and retracting). This structure can well adapt to longitudinal opening, longitudinal extrusion, and circumferential deformation, achieving the purpose of flexibility. The flexible joint 6 is suitable for various situations such as fault dislocation or strong vibration; both ends of the collapsible main body portion 61 are provided with a plurality of connecting portions 62 for extending into the secondary lining, and the plurality of connecting portions 62 are arranged along the circumference of the flexible joint 6. Further, the plurality of connecting portions 62 are evenly distributed and symmetrically arranged in the circumference of the flexible joint.

[0038] In some preferred embodiments, the angle between the connecting portion 62 and the horizontal line where the secondary lining is located is 30-60 degrees, forming an inclined plane. As Figure 2 shown, the cross-sectional shape of the connecting portion 62 is in a Y shape. By adopting this angle setting, it is ensured that the flexible joint 6 is firmly connected to the secondary lining, extending the penetration path of groundwater and avoiding the occurrence of water leakage. If the connecting portion 62 and the horizontal line where the secondary lining is located do not have the above-mentioned angle setting and are directly in a straight line, although the connection function of the connecting portion 62 can also be realized, the occurrence of water leakage cannot be avoided, and the connection firmness will also be greatly reduced.

[0039] In some preferred embodiments, the length of the foldable main body portion 61 is 30 - 100 cm. In some other embodiments, those skilled in the art can also make any appropriate adjustment to the specific length of the foldable main body portion 61 according to the activity of the active fracture.

[0040] In some preferred embodiments, the projection distance of the connecting portion 62 on the horizontal line where the secondary lining is located is more than 10 cm. The main purpose is to ensure a firm connection between the joint and the secondary lining.

[0041] To enable the flexible joint 6 to have better performance in adapting to three-dimensional deformations and have a waterproof function, in some preferred embodiments, the flexible joint 6 is made of a material with certain elasticity and waterproof property, such as rubber material. The foldable main body portion 61 made of rubber material can adapt to various three-dimensional deformations through repeated stretching (expanding and retracting), greatly improving the circumferential deformation ability. Moreover, by this self-adaptive buffering of the impacts brought about by various situations such as fault dislocation or strong vibration, the secondary lining structures at both ends will not be damaged. Of course, in other embodiments, materials similar to the rubber performance can also be used for preparation, not limited to the rubber in this embodiment.

[0042] In some preferred embodiments, both ends of the flexible joint 6 are respectively connected to the secondary lining through the secondary lining end template 8. The structure of the secondary lining end template 8 is as Figure 3 shown. The main function of the secondary lining end template 8 is to retain the concrete at the end of the secondary lining to ensure the successful pouring of the secondary lining, and at the same time fix the flexible joint 6. The secondary lining end template 8 sleeves and presses the end of the flexible joint 6, that is, the flexible joint 6 is clamped at both ends by two secondary lining end templates 8 to fix the flexible joint 6 and form an integral structure with the secondary lining, so as to ensure the connection of the connecting portion with the secondary lining of the pre-poured section and the secondary lining of the post-poured section into an integral whole, improving the waterproof sealing performance.

[0043] To play a better supporting role for the surrounding rock, in some preferred embodiments, the primary support 2 is made of foam concrete. The secondary lining is made of concrete.

[0044] To improve the waterproof sealing performance, the secondary lining is provided with a recess for connecting the water receiving box 7 at the position where it is connected to the flexible joint 6. The water receiving box 7 is installed closely against this recess, which can avoid water leakage.

[0045] Based on the above flexible joint structure, in another embodiment of the present invention, there is also provided an installation method for the tunnel flexible joint 6 structure in the above embodiment, including:

[0046] S1, constructing the primary support 2 of the tunnel;

[0047] S2. Lay a waterproof board 3 under the initial support 2;

[0048] S3. Use the end formwork 8 of the secondary lining to fix one end of the flexible joint 6 and pour it together with the concrete to construct the first-poured section of the secondary lining 4 under the waterproof board 3. Specifically, the end formwork 8 of the secondary lining sleeves and presses one end of the flexible joint 6 to fix the flexible joint 6 and pour it together with the concrete to form an integral structure;

[0049] S4. Use the end formwork 8 of the secondary lining to fix the other end of the flexible joint 6, that is, the end formwork of the secondary lining sleeves and presses the other end of the flexible joint 6, clamp the flexible joint 6 at both ends through two end formworks 8 of the secondary lining, and pour the later-poured section of the secondary lining, so that the flexible joint 6 is connected to the secondary linings at both ends of the shock-absorbing joint as a whole, thereby ensuring that the connecting part 62 is connected to the first-poured section of the secondary lining 4 and the later-poured section of the secondary lining 5 as a whole, and improving the waterproof sealing performance;

[0050] S5. Install a water receiving box 7 under the flexible joint 6. The secondary lining is provided with a recess for connecting the water receiving box 7 at the part connected to the flexible joint 6, and the water receiving box 7 is installed closely against this recess, which can avoid water leakage.

[0051] In the tunnel flexible joint structure in the above embodiments of the present invention, during the implementation process, first lay a waterproof board 3 outside the initial support 2, then construct the first-poured section of the secondary lining and install the flexible joint 6, and then construct the later-poured section of the secondary lining. The flexible joint 6 is connected to the secondary linings at both ends as a whole. Finally, considering aesthetics and waterproofing, install a circumferential water receiving box. Through the three-dimensional deformation adaptability of the flexible joint 6, both the first-poured section of the secondary lining 4 and the later-poured section of the secondary lining 5 can freely expand and contract longitudinally and deform circumferentially, and can adapt to the three-dimensional dislocation under a major earthquake; the flexible joint 6 itself has a good waterproof function, and through the waterproof board 3 and the water receiving box, the waterproof ability of the tunnel flexible joint 6 structure is better. The installation (construction) of the flexible joint 6 is simple and convenient, without using other connecting components (such as bolts) or processes (such as welding), greatly reducing the complexity of the project. Figure 4 It is a schematic diagram of the whole after tunnel construction.

[0052] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present invention. The above preferred features can be combined arbitrarily without conflict.

Claims

1. A tunnel flexible joint structure applicable to active fault zones, characterized in that, Comprising: The primary support, waterproof board and secondary lining are successively arranged downward from the surrounding rock; The secondary lining includes a secondary lining of the first casting section and a secondary lining of the second casting section. A flexible joint capable of three-dimensional deformation self-adaptation is provided between the secondary lining of the first casting section and the secondary lining of the second casting section. The flexible joint is configured to be waterproof; a water receiving box is provided below the flexible joint; The flexible joint includes a telescopic folding main body portion. A plurality of connecting portions for extending into the secondary lining are provided at both ends of the folding main body portion. The plurality of connecting portions are arranged circumferentially along the flexible joint; The included angle between the connecting portion and the horizontal line where the secondary lining is located is 30-60 degrees; the cross-sectional shape of the connecting portion is in a Y shape.

2. The tunnel flexible joint structure applicable to active fault zones according to claim 1, wherein The length of the folding main body portion is 30-100 cm.

3. The tunnel flexible joint structure applicable to active fault zones according to claim 1, characterized in that, The projection distance of the connecting portion on the horizontal line where the secondary lining is located is more than 10 cm.

4. The tunnel flexible joint structure applicable to active fault zones according to claim 1, wherein The flexible joint is made of rubber material.

5. The tunnel flexible joint structure applicable to an active fault zone according to claim 1, characterized in that, Both ends of the flexible joint are respectively connected to the secondary lining through the secondary lining end template. The secondary lining end template sleeves and presses the ends of the flexible joint to fix the flexible joint and form an integral structure with the secondary lining.

6. The tunnel flexible joint structure applicable to active fault zones according to claim 1, characterized in that, The primary support uses foamed concrete.

7. The tunnel flexible joint structure applicable to active fault zones according to claim 1, wherein The secondary lining uses concrete.

8. An installation method for the tunnel flexible joint structure applicable to active fractures according to any one of claims 1-7, characterized in that, Comprising: The primary support of the construction tunnel; Laying a waterproof board below the primary support; Fixing one end of the flexible joint with the secondary lining end template and casting it together with the concrete. Constructing the secondary lining of the first casting section below the waterproof board; Using the secondary lining end template to fix the other end of the flexible joint and casting the secondary lining of the second casting section, so that the flexible joint is connected to the secondary linings at both ends of the shock-absorbing joint as a whole; Installing a water receiving box below the flexible joint.

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