Tunnel nested pipe protection structure with anti-seepage and anti-shear capacities

Abstract

The utility model belongs to the field of tunnel engineering, and relates to a tunnel nested pipe protection structure with anti-seepage and anti-shear capacities, which comprises a main body tunnel, an external pipe body and a flexible embedded tunnel, the outer pipe body is located between the two main body tunnels, and the outer pipe body and the main body tunnels are of an integrated structure. The flexible embedded tunnel is located in the outer pipe body, and the two ends of the flexible embedded tunnel are connected with the ends of the two main body tunnels through flexible joints correspondingly. A dislocation buffer area is formed between the outer wall of the flexible embedded tunnel and the inner wall of the outer pipe body; a plurality of flexible supporting structures are symmetrically arranged in the dislocation buffering area. An external tubular space is constructed to form a nested structure, and dislocation allowance is provided for an internal flexible pipeline; the anti-seepage capacity of the inner pipe is effectively improved through the waterproof barrier and the filling material of the outer pipe; when shear dislocation occurs in the ground layer, shear deformation is dispersed on the flexible embedded tunnel, and the situation that the internal tunnel directly bears large shear force is avoided.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of tunnel engineering and relates to a tunnel nested pipe protection structure with anti-seepage and shear resistance. BACKGROUND

[0002] Seepage problems are prone to occur near geological faults in submarine tunnels, and when shear dislocation occurs in the faults, the tunnels will directly bear strong shear forces, which may lead to structural damage. In addition, due to the long span of the tunnels, once seepage or structural damage occurs, it will pose a great threat to personnel safety, and the difficulty of escape is extremely high, so the safety hazard cannot be ignored.

[0003] For the seepage and shear resistance problems in the cross-fault area, relevant patents have proposed corresponding solutions. For example, Chinese patent CN216841726U proposes a shield tunnel anti-seepage device. The device reinforces the connection between the segment body through the support plate and the fixed rod to improve the fixing effect, and simultaneously seals the connection of the segment body through the rubber pad to improve the waterproof effect and reduce the occurrence of water leakage and seepage. Chinese patent CN218542269U proposes a tunnel support structure for shear resistance and energy release in layered surrounding rock tunnels, which can achieve the requirements of shear resistance and energy release through the setting of pre-stressed anchor rods and energy release mechanisms, effectively preventing the extrusion deformation of layered surrounding rock due to interlayer shear slip, and simultaneously releasing part of the surrounding rock deformation stress to protect the initial support in the tunnel from being damaged and improve the safety performance. These technologies have solved the problems of seepage and stability in tunnel engineering to some extent.

[0004] However, when facing large shear dislocation of geological faults, the tunnel pipe directly bears large shear forces, which may lead to the shearing of the tunnel, and the existing technology cannot achieve effective disaster prevention and mitigation effect, so a nested pipe protection scheme with anti-seepage and shear resistance is needed to provide more comprehensive protection for submarine tunnels in geological fault areas. UTILITY MODEL CONTENTS

[0005] The utility model aims to provide a protection scheme for submarine tunnels, especially a nested pipe protection scheme applied in geological fault areas, which enhances the anti-seepage performance and shear resistance of the tunnel through the nested pipe structure. The scheme can effectively solve the problems of seepage and shear forces of submarine tunnels near geological faults and improve the structural safety and durability of the tunnels. The scheme forms a nested structure by constructing an external tubular space to provide dislocation allowance for the internal flexible pipe, effectively improves the anti-seepage capacity of the inner pipe through the outer pipe waterproof barrier and filling material, and disperses the shear deformation on the flexible inner nested tunnel when the stratum undergoes shear dislocation, avoiding the direct bearing of large shear forces by the internal tunnel. The scheme provides a new safety guarantee idea for cross-fault tunnel engineering.

[0006] In order to achieve the above object, the utility model adopts the following technical scheme:

[0007] A tunnel nested pipe protection structure with anti-seepage and shear resistance capacity, comprising a main tunnel 1, an outer pipe body 2 and a flexible inner embedded tunnel 4, wherein the outer pipe body 2 is located between two main tunnels 1, the outer pipe body 2 and the main tunnel 1 are an integral structure, and the diameter of the outer pipe body 2 is greater than that of the main tunnel 1; the flexible inner embedded tunnel 4 is located in the outer pipe body 2, and the two ends of the flexible inner embedded tunnel 4 are connected with the end portions of the two main tunnels 1 through flexible joints 5 respectively; the diameter of the flexible inner embedded tunnel 4 is the same as that of the main tunnel 1, and a dislocation buffer zone 3 is formed between the outer wall of the flexible inner embedded tunnel 4 and the inner wall of the outer pipe body 2.

[0008] A plurality of flexible support structures 6 are symmetrically arranged in the dislocation buffer zone 3, and the two ends of each flexible support structure 6 are fixedly connected with the outer wall of the flexible inner embedded tunnel 4 and the inner wall of the outer pipe body 2 respectively.

[0009] The utility model has the advantages of:

[0010] 1. Enhanced anti-seepage performance: through the double protection of the outer pipe body and the anti-seepage material, the influence of fault seepage on the tunnel is effectively reduced, and the dryness and safety inside the tunnel are ensured.

[0011] 2. Dispersing shear stress: the shear end distance is enlarged, when the stratum occurs shear dislocation, the shear deformation is dispersed on the flexible inner embedded tunnel, direct shear force of the tunnel is avoided, thereby the shear resistance capacity of the tunnel is effectively improved, and the damage risk is reduced.

[0012] 3. Improved structural safety: through the flexible nested design, the requirements of anti-seepage and shear resistance are considered, a new safety protection idea is provided for the cross-fault tunnel engineering, and the overall safety of the tunnel is improved.

[0013] 4. Adapt to complex geological conditions: the scheme can adapt to the complex environmental conditions near the geological fault, and has significant engineering application potential and safety protection significance. BRIEF DESCRIPTION OF DRAWINGS

[0014] Fig. 1 It is a whole schematic view of the flexible nested pipe scheme.

[0015] Fig. 2 It is a cross-sectional schematic view of the flexible nested pipe scheme.

[0016] Fig. 3 It is a shear resistance protection schematic view of the flexible nested pipe when the stratum occurs dislocation.

[0017] In the drawing: 1, main tunnel; 2, outer pipe body; 3, dislocation buffer zone; 4, flexible inner embedded tunnel; 5, flexible joint; 6, flexible support structure. Detailed Implementation

[0018] The specific embodiments of this utility model are further described below with reference to the accompanying drawings and technical solutions.

[0019] This utility model discloses a design for a tunnel nested pipe protection structure with seepage prevention and shear resistance capabilities, which includes the following aspects:

[0020] 1. Construct an external tubular space: When the tunnel is excavated to the vicinity of a geological fault, an external tubular space larger than the tunnel diameter is formed by expanding the excavation diameter, providing sufficient displacement margin for the tunnel to cope with the impact of geological fault displacement.

[0021] 2. Constructing a flexible embedded tunnel: Inside the external tubular space, a flexible tunnel with lower stiffness than conventional tunnels is constructed. The space between the flexible tunnel and the outer tube is filled with a soft, impermeable material, while ensuring that the flexible tunnel is effectively supported to enhance the tunnel's impermeability and shear resistance.

[0022] 3. Application of anti-seepage materials: Fill the space between the outer pipe and the flexible embedded tunnel with anti-seepage soft materials, such as polymer elastic materials and rubber concrete. These materials can absorb shear deformation and prevent water seepage, thereby reducing the impact of fault seepage on the tunnel.

[0023] 4. Optimization of support structure: A flexible support structure is installed between the flexible tunnel and the filling material to ensure uniform stress on the embedded tunnel, adapt to displacement, and further improve the shear resistance of the tunnel.

[0024] like Figs. 1-3 As shown, a tunnel-nested pipe protection structure with seepage prevention and shear resistance capabilities includes a main tunnel 1, an outer pipe 2, and a flexible inner tunnel 4. The main tunnel 1 and the flexible inner tunnel 4 are connected by a flexible joint 5, leaving a certain amount of space for movement. A slip buffer zone 3 is located between the outer pipe 2 and the flexible inner tunnel 4, filled with a seepage-resistant flexible material. A flexible support structure 6 is arranged between the flexible tunnel and the filling material to ensure uniform stress on the inner tunnel and accommodate slip displacement.

[0025] The flexible joint 5 is a bellows-type flexible joint made of high-strength rubber (such as neoprene (CR) or ethylene-propylene-diene rubber (EPDM)) or high-molecular composite material (such as polyurethane (PU) or fluororubber (FKM)), with good elastic deformation ability and waterproof performance. The two ends of the flexible joint 5 are connected to the main tunnel 1 and the flexible embedded tunnel 4 through flanges, and the flanges are fixed by bolts to ensure the firmness and sealing of the connection. The inside of the flexible joint 5 is provided with a waterproof sealing ring, and the outside is coated with a waterproof coating to prevent groundwater from seeping in. The bellows structure allows the flexible joint 5 to have a certain displacement ability in the axial, radial and angular directions, thereby adapting to the deformation of the tunnel caused by geological fault dislocation, while maintaining the continuity and sealing of the tunnel.

[0026] The flexible support structure 6 is a multi-directional articulated support structure made of high-strength elastic material (such as rubber, polyurethane or high-molecular composite material), with a bellows or spring-like main body that can provide elastic deformation ability in the axial, radial and angular directions. The two ends of the flexible support structure 6 are connected to the outer pipe body 2 and the flexible embedded tunnel 4 through flanges or articulated joints, ensuring uniform stress and allowing a certain displacement. The inside of the flexible support structure 6 can be filled with damping material (such as viscoelastic material) to further absorb shear stress and reduce vibration transmission.

[0027] The outer pipe body 2 is made of a material with certain load supporting ability, and its structure size, density, elastic modulus and Poisson's ratio are determined by the tunnel design load, the design of shear dislocation allowance of the stratum, the geological environment of the tunnel and the relevant specifications. The specific material can be selected from high-strength concrete (such as C50 and above), steel pipe (such as Q345B) or fiber-reinforced composite material (such as GFRP) to meet different geological conditions and load requirements.

[0028] The flexible embedded tunnel 4 is made of a deformed material, and its structure size, density, elastic modulus and Poisson's ratio are determined by its design load, design deformation range and traffic space requirement. The specific material can be selected from steel shell-concrete composite pipe, high-molecular composite material (such as polyurethane) or rubber-steel composite pipe to ensure good deformation ability and load bearing performance.

[0029] The filling material in the dislocation buffer zone 3 is determined by the space size between the outer pipe body and the flexible embedded tunnel, the impermeability index and the deformation design range. The specific material can be selected from high-molecular elastic material (such as polyurethane elastomer), rubber concrete or foamed concrete to provide good impermeability and deformation absorption ability.

[0030] The flexible support structure 6 design parameters, including its material selection, geometric dimensions and layout, are determined by the stress characteristics of the flexible tunnel and the activity of the geological fault to ensure that it can effectively disperse shear stress and protect the tunnel structure from damage when the geological fault moves. Specific materials can be selected from high-strength steel (such as Q345B), fiber-reinforced composite materials (such as GFRP), or rubber-steel composite supports to provide sufficient elasticity and strength.

[0031] The specific preparation and use process is as follows:

[0032] 1. Preparation

[0033] Fine exploration is carried out in the geological fault area to determine the fault position, fault activity, stratum shear characteristics and water seepage risk. According to the exploration results, the design parameters are optimized, including the excavation diameter, the size of the outer pipe and the embedded tunnel, the type and thickness of the filling material. Select a shield machine or drill and blast method equipment suitable for large diameter excavation to ensure that it can cope with complex geological conditions. Equip with anti-seepage material injection device and flexible support construction equipment.

[0034] 2. Tunnel excavation to fault area

[0035] Increase the excavation diameter in the fault area to form a tubular space larger than the main diameter of the main tunnel 1, and reserve enough displacement buffer zone. When increasing the excavation diameter, the surrounding stratum reinforcement needs to be strengthened to avoid stratum collapse. Grouting reinforcement or freezing method reinforcement is carried out in the fault area to stabilize the stratum and control underground water seepage. The grouting material is selected from concrete or composite materials with good impermeability and shear resistance.

[0036] 3. Outer pipe construction

[0037] In the enlarged excavation space, the construction of the outer pipe body 2 is completed by using the assembly type or cast-in-place construction method. The outer pipe material is selected from high-strength concrete or steel pipe and other materials, and waterproof measures are strengthened. A waterproof barrier is set up outside the outer pipe, combined with a waterproof layer and a drainage system, to effectively resist fault water seepage.

[0038] 4. Construction of embedded flexible tunnel

[0039] In the interior of the outer pipe body 2, a flexible embedded tunnel 4 is built, and the material is selected from composite materials with low rigidity and high ductility, such as steel shell-concrete composite pipe, etc. The flexible tunnel can be assembled in sections and connected by flexible joints 5, leaving a certain activity space. In the displacement buffer zone 3 between the flexible embedded tunnel 4 and the outer pipe body 2, anti-seepage soft materials (such as high molecular elastic materials, rubber concrete, etc.) are injected. This material can not only absorb shear deformation, but also prevent water seepage. Flexible support structure 6 is arranged between the outer pipe body 2 and the flexible embedded tunnel 4 to ensure that the flexible embedded tunnel 4 is uniformly stressed and adapts to the displacement.

[0040] 5. End and test

[0041] Ensure that the external tube 2 is well sealed at the junctions with the main tunnel 1 and the flexible inner embedded tunnel 4. In the fault zone, a monitoring system is installed, including displacement, stress and water infiltration monitoring. The fault zone is tested for shear resistance and water infiltration, ensuring that the nested structure meets the design requirements. The integrity of the nested structure is checked in its entirety, confirming that there are no voids in the filling material and no deviation in the flexible tunnel.

Claims

1. A tunnel embedded pipe protection structure with anti-seepage and shear resistance, characterized in that, The tunnel nested pipe protection structure with anti-seepage and shear resistance capability comprises a main tunnel (1), an outer pipe body (2) and a flexible inner embedded tunnel (4); the outer pipe body (2) is located between two sections of the main tunnel (1), the outer pipe body (2) and the main tunnel (1) are an integral structure, and the diameter of the outer pipe body (2) is greater than that of the main tunnel (1); the flexible inner embedded tunnel (4) is located in the outer pipe body (2), and the two ends of the flexible inner embedded tunnel (4) are connected with the end portions of the two sections of the main tunnel (1) through flexible joints (5) respectively; the diameter of the flexible inner embedded tunnel (4) is the same as that of the main tunnel (1), and a dislocation buffer zone (3) is formed between the outer wall of the flexible inner embedded tunnel (4) and the inner wall of the outer pipe body (2).

2. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 1, characterized in that, A plurality of flexible support structures (6) are symmetrically arranged in the dislocation buffer zone (3), and the two ends of each flexible support structure (6) are fixedly connected with the outer wall of the flexible inner embedded tunnel (4) and the inner wall of the outer pipe body (2) respectively.

3. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 1, characterized in that, The structure of the flexible joint (5) is a bellows type flexible joint, the two ends of the flexible joint (5) are connected with the main tunnel (1) and the flexible inner embedded tunnel (4) through flanges respectively, and the flanges are fixed by bolts; a waterproof sealing ring is arranged in the flexible joint (5), and a waterproof coating is coated on the outside of the flexible joint (5).

4. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 1, characterized in that, The flexible joint (5) is made of high-strength rubber or high-molecular composite material; the high-strength rubber is, for example, neoprene or ethylene-propylene-diene rubber; and the high-molecular composite material is, for example, polyurethane or fluororubber.

5. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 2, characterized in that, The flexible support structure (6) is in the shape of a bellows or a spring, and the two ends of the flexible support structure (6) are connected with the outer pipe body (2) and the flexible inner embedded tunnel (4) through flanges or hinged joints.

6. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 2, characterized in that, The flexible support structure (6) is made of high-strength elastic material, and the inside of the flexible support structure (6) is filled with damping material; the high-strength elastic material is rubber or polyurethane.

7. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 1, characterized in that, The material of the outer pipe body (2) is high-strength concrete, steel pipe or fiber reinforced composite material; the high-strength concrete is C50 or above, the steel pipe is Q345B, and the fiber reinforced composite material is GFRP.

8. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 1, characterized in that, The flexible inner embedded tunnel (4) is made of deformed material, and the material is selected from a steel shell-concrete composite pipe, a high-molecular composite material or a rubber-steel composite pipe; the high-molecular composite material is polyurethane.

9. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 1, characterized in that, The dislocation buffer zone (3) is filled with a material, and the material is selected from a high-molecular elastic material, rubber concrete or foam concrete; the high-molecular elastic material is a polyurethane elastomer.

10. The tunnel embedded pipe protection structure with anti-seepage and anti-shear capacity according to claim 2, characterized in that, The material of the flexible support structure (6) is selected from high-strength steel material, fiber reinforced composite material or rubber-steel composite support; the high-strength steel material is Q345B, and the fiber reinforced composite material is GFRP.

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