Tunneling through active fault structures

Abstract

The application discloses a tunnel crossing active fault structure design system and belongs to the field of tunnel construction. The tunnel crossing active fault structure design system comprises a displacement space, a support system and a tunnel structure. The support system comprises a vertical support system and a transverse hinge constraint system. The displacement space, the support system and the tunnel structure are all located in surrounding rock at an active fault. The support system and the tunnel structure are located in the displacement space. The vertical support system is connected with the inner wall of the displacement space and the tunnel structure respectively. The transverse hinge constraint system is located on both sides of the tunnel structure and is connected with the outer wall of the side wall of the tunnel structure and the outer wall of the displacement space respectively. The tunnel crossing active fault system has wide application range and can realize that the tunnel is stable at the initial position and keeps the constant support force when the fault dislocation occurs, so that the purpose of resisting fault dislocation is achieved.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, specifically relating to a fault-resistant structure for tunnels crossing active faults. Background Technology

[0002] The main solutions currently used for tunneling through active faults and their drawbacks are as follows:

[0003] 1. If possible, avoid these faults when selecting the tunnel route after preliminary geological surveys (Song Yuxiang, Liu Yong, eds. Tunnel Engineering. Beijing: China Architecture & Building Press. 2018: 34-36.); however, due to limitations such as geographical conditions, this method is only applicable to some projects.

[0004] 2. Using rigid protective measures to strengthen the rigidity of the tunnel itself (e.g., increasing the strength of materials, anchor spraying support, etc.) to resist the additional loads imposed on the structure by fault displacement (Deng Zhongfu. Design parameters and safety analysis of segmental tunnels under fault displacement [J]. Western Transportation Technology, 2021, No. 162(01): 126-130.); however, this method will greatly increase the construction cost, and practice has proven that this method is not very effective.

[0005] 3. Setting up flexible connection sections: In the vicinity of faults, some flexible materials or structures are used in the tunnel to allow the tunnel to deform with the fault movement, thereby reducing the additional internal forces generated by the fault movement (Li Guoliang, Zhang Jing, Liu Guoqing, et al. Connection structure for tunnels crossing active faults [P]. Shaanxi Province: CN111810189B, 2022-03-18.). However, this method will produce large deformations due to the influence of fault movement, which cannot meet the deformation requirements of tunnels for certain purposes (e.g., high-speed railway tunnels).

[0006] 4. Over-excavation design: The tunnel cross-section is enlarged to meet the normal function during fault displacement. The amount of enlargement is determined according to the displacement of the fault (Jiang Shuping, Li Peng, Lin Zhi. Countermeasures for Fault Resistance Design of Tunnels Crossing Active Fault Zones [J]. Journal of Chongqing Jiaotong University (Natural Science Edition), 2008, 27(06):1034-1036+1041.). However, this method still cannot prevent the tunnel structure from displacing at the fault location, and regular maintenance is required.

[0007] Based on the above problems, this invention proposes a tunnel crossing a live fault structure that can maintain the tunnel in its initial position and the stress on it when the fault moves, thereby achieving the purpose of resisting fault movement. Summary of the Invention

[0008] This invention provides a tunnel crossing active fault structure. This system can maintain the stability of the tunnel in its initial position and the constant stress when the fault moves, thereby achieving the purpose of resisting faulting.

[0009] The technical solution of this invention:

[0010] A tunnel traversing an active fault structure includes a displacement space, a tunnel structure, and a support system;

[0011] The displacement space is located within the surrounding rock at the fault crossing point;

[0012] The tunnel structure is located within the displacement space;

[0013] The support system includes a vertical support system and a horizontal hinge constraint system, located within the displacement space and outside the tunnel structure;

[0014] When the fault shifts, the tunnel lining structure remains in its initial position and moves freely up and down within the displacement space. The vertical support system adjusts the vertical support force on the tunnel structure by controlling the weight of the weights, and the provided vertical support force remains unchanged during fault shift. The transverse hinge constraint system provides transverse displacement constraint for the tunnel, but does not constrain the vertical displacement of the tunnel structure.

[0015] The tunnel structure is reserved with a displacement space between itself and the surrounding rock. The cross-sectional shape of the displacement space includes, but is not limited to, an ellipse.

[0016] The length of the displacement space in the longitudinal direction of the tunnel L The following formula should be satisfied:

[0017]

[0018] In the formula: f This is the fault displacement. ω To standardize the allowable error, %

[0019] The longitudinal length of the displacement space is determined according to the deformation control standard of the tunnel structure, and its longitudinal profile includes, but is not limited to, the inner wall contour. S Shaped curve.

[0020] The vertical support system is used to increase the supporting force of the catenary cable on the tunnel structure. The increase is adjusted by controlling the number of movable pulley blocks. The vertical support system includes a movable pulley system, a fixed pulley system, fixed anchor cables, a fixed structure, catenary cables, and weights. The fixed anchor cables and fixed pulley system are fixed to the inner wall of the displacement space, and the fixed structure is fixed to the outer wall of the tunnel structure. The fixed structure is used to fix the movable pulley blocks. The catenary cable is wound around the movable pulley system, the fixed pulley system, and the fixed anchor cables, and its two ends are connected to weights. The displacement space includes space reserved for the weights to move up and down.

[0021] The fixed structure includes a load-bearing rod, a base, a pin, and a rotating component; the base is fixed to the outer wall of the tunnel structure, the rotating component is connected to the load-bearing rod, the load-bearing rod is connected to the movable pulley block, the base and the rotating component are connected by a pin, and the rotating component can rotate around the pin.

[0022] The vertical support system adjusts the vertical support force applied to the tunnel structure by controlling the weight of the weights.

[0023] The transverse hinge constraint system is located within the displacement space, with its two ends fixed to the outer wall of the tunnel structure's sidewall and the inner wall of the displacement space, respectively. It consists of links arranged vertically. Since each link is non-extensible, it constrains the transverse displacement of the tunnel structure. However, since its vertical direction is a movable system, it does not constrain the vertical displacement of the tunnel structure.

[0024] The vertical support system and the horizontal hinge constraint system are arranged in an alternating manner to avoid mutual interference in space.

[0025] The tunnel structures include, but are not limited to, highway tunnels, railway tunnels, water diversion tunnels, and various utility tunnels.

[0026] The beneficial effects of this invention are as follows: This invention separates the tunnel structure and the displaced surrounding rock from the original direct contact by setting up a displacement space. The direct force between the tunnel structure and the surrounding rock is transmitted through a lateral hinge constraint system and a vertical support system located between the two structures. The lateral hinge constraint system only constrains the lateral displacement of the tunnel structure and not the vertical displacement. The vertical support system connects the tunnel structure and the surrounding rock in series through a load-bearing cable. One end of the load-bearing cable is connected to a weight, and the tension in the load-bearing cable is equal to the weight of the weight. Thus, the vertical support force on the tunnel remains constant throughout the fault displacement process. Since the displacement space isolates the displacement during fault displacement, the vertical support system keeps the force on the tunnel structure constant. Therefore, the tunnel of this invention has a self-adjusting ability when crossing an active fault structure, thereby maintaining the stability of the tunnel structure, maintaining operational safety, and achieving the purpose of tunnel anti-faulting. It can be applied to highway tunnels, railway tunnels, water diversion tunnels, and various pipe corridors, etc., with a wide range of applications. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the cross-sectional layout of the vertical support system for the tunnel crossing the active fault structure of the present invention.

[0028] Figure 2 This is a schematic diagram of the cross-sectional layout of the transverse hinge constraint system for tunneling through an active fault structure according to the present invention.

[0029] Figure 3 This is a schematic diagram of the displacement space of the tunnel crossing the active fault structure of the present invention.

[0030] Figure 4 for Figure 1 A schematic diagram of the system for increasing lifting capacity in the vertical support system.

[0031] Figure 5 for Figure 4 A schematic diagram of the movable pulley system in the system for increasing lifting capacity.

[0032] Figure 6 for Figure 1 A schematic diagram of the fixed structure in the diagram.

[0033] In the diagram: 1. Surrounding rock; 2. Tunnel structure; 3. Movable pulley system; 4. Fixed pulley system; 5. Fixed anchor cable; 6. Displacement space; 7. Fixed structure; 8. Load-bearing cable; 9. Weight; 10. Lateral hinge restraint system; 11. Movable fault; 12. Inner wall of displacement space; 13. Movable pulley block; 14. Load-bearing rod; 15. Rotating component; 16. Pin; 17. Base. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0035] The tunnel crossing active fault structure proposed in this invention includes a tunnel lining structure, displacement space, and support system. For example... Figure 1 and Figure 2 As shown, the tunnel passes through active fault structures all within the surrounding rock 1, which is the soil and rock mass near active fault 11; the tunnel structure 2 is composed of various lining segments, including but not limited to highway tunnels, railway tunnels, water diversion tunnels, and various pipe galleries, depending on their function. To facilitate the fixing and connection of the catenary 8, a fixing structure 7 is pre-reserved on the outer wall of the tunnel structure 2; as shown... Figures 1 to 3 As shown, when the active fault 11 shifts, to ensure the tunnel structure 2 remains stable in its initial position, a displacement space 6 is reserved for the tunnel structure 2 in advance based on the amount of fault shift. In addition, the displacement space 6 also provides reserved space for the transverse hinge restraint system 10 and the vertical support system, and specifically, it also provides reserved space for the vertical movement of the weight 9. Figure 3 As shown, the length of displacement space 6 in the longitudinal direction of the tunnel is... L The following formula should be satisfied:

[0036]

[0037] In the formula: f This is the fault displacement. ω To standardize the allowable error (%).

[0038] Furthermore, such as Figure 1As shown, the vertical support system includes a movable pulley system 3, a fixed pulley system 4, fixed anchor cables 5, a load-bearing cable 8, and a weight 9. To increase the support capacity of the vertical support system, the following features are specifically designed for it: Figure 4 The lifting capacity enhancement system shown herein, the lifting capacity enhancement system by means of, as Figure 5 The movable pulley system 3 shown amplifies the tension applied by the weight 9 to the support cable 8 by several times and transmits it to the tunnel structure 2 through the support rod 14. The amplification factor is determined by the number of movable pulley groups 13 in the movable pulley system 3. When the active fault 11 shifts, the support cable 8 elongates and shortens according to the change in the amount of tunnel shift, and drives the weight 9 to move up and down, thereby counteracting the impact of the shift on the tunnel structure 2. Throughout the process, the vertical force on each fixed structure 7 of the tunnel remains constant, and the vertical constant support force applied to the fixed structure 7 is constant. F The following formula can be used for calculation:

[0039]

[0040] In the formula: k This refers to the number of movable pulleys in the movable pulley block 13. M The weight of the weight 9.

[0041] The fixed pulley system 4 and the fixed anchor cable 5 are located on the inner wall 12 of the displacement space and fixed to the surrounding rock 1. The force in the load-bearing cable 8 is transmitted to the surrounding rock 1 through the above two structures. In addition, the fixed anchor cable 5 also plays the role of changing the direction of the load-bearing cable 8.

[0042] like Figure 6 As shown, the fixed structure 7 includes a base 15, a pin 16, and a rotating component 17; the base 15 is fixed to the outer wall of the tunnel structure 2, the rotating component 17 is connected to the load-bearing rod 14, and the base 15 and the rotating component 17 are connected by the pin 16. The rotating component 17 can rotate around the pin 16 to eliminate the bending moment in the upper load-bearing rod, so that the supporting force transmitted to the tunnel structure 2 is a single tensile force.

[0043] Furthermore, the transverse hinge constraint system 10 is located at both ends within the displacement space and is fixed to the tunnel structure 2 and the inner wall 12 of the tunnel displacement space, respectively. The main function of the system is to constrain the transverse movement of the tunnel structure 2, but not to constrain the vertical movement.

[0044] When the fault shifts, the fixed pulley 4 and fixed anchor cable 5 will move along with the fault. The load-bearing cable connected to the above two structures will compensate for the fault shift by elongating and shortening the weight 9. During the compensation and adjustment process, since the weight of the weight 9 remains constant, the tension in the load-bearing cable 8 is always a constant value. It is also due to the compensation and adjustment effect of the load-bearing cable that the impact of the fault shift on the tunnel structure 2 is blocked. Thus, the tunnel structure 2 can remain stable in its initial position and maintain a constant supporting force when the fault shifts, thereby achieving the purpose of resisting fault shift.

Claims

1. A tunnel traversing an active fault structure, characterized in that, The tunnel traverses an active fault structure, including displacement space, tunnel structure, and support system; The displacement space is located within the surrounding rock at the fault crossing point; The tunnel structure is located within the displacement space; The support system includes a vertical support system and a horizontal hinge constraint system, located within the displacement space and outside the tunnel structure; When the fault shifts, the tunnel structure remains in its initial position and moves freely up and down within the displacement space. The vertical support system adjusts the vertical support force on the tunnel structure by controlling the weight of the weights, and the provided vertical support force remains unchanged during fault shift. The lateral hinge constraint system provides lateral displacement constraint for the tunnel, but does not constrain the vertical displacement of the tunnel structure. The vertical support system is used to increase the supporting force of the catenary cable on the tunnel structure. The increase is adjusted by controlling the number of movable pulley blocks. The vertical support system includes a movable pulley system, a fixed pulley system, fixed anchor cables, a fixed structure, catenary cables, and weights. The fixed anchor cables and fixed pulley system are fixed to the inner wall of the displacement space, and the fixed structure is fixed to the outer wall of the tunnel structure. The fixed structure is used to fix the movable pulley blocks. The catenary cable is wound around the movable pulley blocks, the fixed pulley system, and the fixed anchor cables, and its two ends are connected to weights. The displacement space includes space reserved for the weights to move up and down. The fixing structure includes a load-bearing rod, a base, a pin, and a rotating component; The base is fixed to the outer wall of the tunnel structure. The rotating component is connected to the load-bearing rod, the load-bearing rod is connected to the movable pulley block, and the base and the rotating component are connected by a pin. The rotating component can rotate around the pin. The transverse hinge constraint system is located within the displacement space, with its two ends fixed to the outer wall of the tunnel structure's sidewall and the inner wall of the displacement space, respectively. It consists of links arranged vertically. Since each link is non-extensible, it constrains the transverse displacement of the tunnel structure. However, since the transverse hinge constraint system is a movable system in the vertical direction, it does not constrain the vertical displacement of the tunnel structure.

2. The tunnel crossing an active fault structure according to claim 1, characterized in that, The tunnel structure has a reserved displacement space between itself and the surrounding rock, and the cross-sectional shape of the displacement space is elliptical.

3. The tunnel crossing an active fault structure according to claim 1, characterized in that, The length of the displacement space in the longitudinal direction of the tunnel L The following formula should be satisfied: In the formula: f This is the fault displacement. ω To standardize the allowable error, % The longitudinal length of the displacement space is determined according to the deformation control standard of the tunnel structure, and its longitudinal profile inner wall contour is as follows: S Shaped curve.

4. The tunnel crossing an active fault structure according to claim 1, characterized in that, The vertical support system adjusts the vertical support force applied to the tunnel structure by controlling the weight of the weights.

5. The tunnel crossing an active fault structure according to claim 1, characterized in that, The vertical support system and the horizontal hinge constraint system are arranged in an alternating manner to avoid mutual interference in space.

6. The tunnel crossing an active fault structure according to claim 1, characterized in that, The tunnel structure includes highway tunnels, railway tunnels, water diversion tunnels, and various utility tunnels.

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