A shield tunnel deformation autonomous regulation model test device and test method

Abstract

The application discloses a kind of self-regulation and control model test device and test method of shield tunnel deformation, it mainly includes model test box structure, tunnel initiative internal pressure regulation and control composite reinforcement system and tunnel initiative external pressure regulation system, the device can simulate the deformed shield segment under the intervention of self-regulation and control internal pressure and external pressure, the change situation of elliptical deformation tunnel displacement adjustment recovery condition and tunnel surrounding soil, using a kind of initiative internal pressure recovery part transverse elliptical deformation, in interface synchronous paste aramid fiber cloth method to improve tunnel bearing capacity, and by transverse or longitudinal control soil, to realize initiative adjustment to shield tunnel deformation or settlement.Not only effectively solve the problem of rapid and efficient reinforcement of shield tunnel, but also form a complete shield tunnel and soil self-regulation and control system, specially aiming at potential structural risk caused by tunnel deformation, quickly and accurately intervene, significantly improve the ability of shield tunnel to resist external load.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering technology in geotechnical and underground engineering, and in particular relates to an autonomous control model test device and test method for shield tunnel deformation. Background Technology

[0002] Shield tunneling technology, due to its high level of mechanization and safe construction advantages, is widely used in urban rail transit construction. However, shield tunnels that have been in operation for many years may experience problems such as water leakage, cracks, and large deformations in the lining structure. Currently, internal reinforcement is mainly achieved through steel plates or external reinforcement through grouting to the outside of the tunnel. While these methods are effective, they are mostly passive reinforcements. Therefore, exploring active control technologies for tunnels has become a highly promising new approach in the field of tunnel maintenance and reinforcement.

[0003] Research on various structural defects that occur during the construction and operation of shield tunnels usually focuses on passive repair and reinforcement strategies, which cannot change the elliptic deformation that has already occurred. In order to solve this problem more effectively, this study adopts a comprehensive autonomous adjustment and control strategy, which focuses on regulating the deformation of shield tunnels in different directions, fundamentally improving structural stability and extending their service life.

[0004] Currently, for shield tunnel model tests, the application No. 201910558112.1, "A Modular Soil Box for Subway Similarity Simulation Test", designs four side boxes with steel plates as baffles and observation windows on the side boxes. However, the side boxes are not transparent as a whole, which is not intuitive and is not conducive to observing and recording changes in the model structure and the surrounding soil. The application with application number 202311106365.8, "A Bag-Type Grouting Anchor," primarily uses the bag for grouting to achieve different anchoring effects. However, the airbag in this patent can increase or decrease in volume to restore tunnel deformation and also provides a certain buffering effect. The application with application number 202110544145.8, "A Multi-Dimensional Active Control Method for Regulating Tunnel Vector Deformation through Flexible Expansion," regulates tunnel deformation through flexible expansion. However, when applied to the bottom of the tunnel, it easily causes the arch bottom to rise while the arch top remains unchanged. However, this patent has an internal support system to ensure that the tunnel does not deform when applied to the arch bottom, achieving an overall lifting effect. The application with application number 202210817169.0, "A Model Test Device and Test Method for Shield Tunnel Lining," mainly uses a manual method to alternately paste aramid fiber cloth onto the inner surface of the tunnel segments for repair and reinforcement. However, it fails to use an internal pressure device to lift the aramid fiber cloth to solidification, thus failing to make the fiber cloth adhesion more secure.

[0005] However, existing shield tunnel reinforcement testing devices lack clarity on tunnel repair mechanisms and a clear understanding of soil change processes. These devices are not effectively suited to the time constraints of tunnel windows requiring rapid repair. Therefore, there is an urgent need to develop a highly visualized active control model testing device for shield tunnels to facilitate in-depth experimental research. This device will enable researchers to observe and analyze the behavior and response of tunnels under various stress conditions in real time, thus providing theoretical basis and practical guidance for the rapid repair of shield tunnels. Summary of the Invention

[0006] The purpose of this invention is to provide an autonomous control model test device and test method for shield tunnel deformation, which addresses the shortcomings of passive repair technology. It can comprehensively consider the active and moderate repair and reinforcement of shield segment deformation and the active compensation measures for soil loss, and has significant scientific research significance for improving the test level in this field.

[0007] The technical solution of the present invention is as follows: an autonomous control model test device for shield tunnel deformation, including a model test box structure, the model test box structure being an outer frame mainly composed of channel steel and corner columns, and an interior rectangular structure enclosed by plexiglass panels; it also includes a tunnel active internal pressure control composite reinforcement system and a tunnel active external pressure control system;

[0008] The tunnel active internal pressure regulation composite reinforcement system includes an arc-shaped base frame, jacks, an arc-shaped jacking frame, and aramid fiber cloth. The outer arc surfaces of the arc-shaped jacking frame and the arc-shaped base frame are respectively mounted on the inner surfaces of the upper and lower shield segments. Jacks for jacking are placed between the arc-shaped jacking frame and the arc-shaped base frame. Aramid fiber cloth is laid on the outer arc surface of the arc-shaped base frame and / or the arc-shaped jacking frame.

[0009] The tunnel active external pressure control system includes a drill bit and a drill rod with one end connected to the drill bit. Multiple deformable bodies are fixed along the length of the drill rod, and each deformable body includes an airbag equipped with an air injection system.

[0010] The tunnel active internal pressure regulation composite reinforcement system is installed inside the tunnel, while the tunnel active external pressure regulation system is installed on the side and / or below the tunnel.

[0011] The deformable body is fixed to the outside of the drill rod by a metal sleeve. The airbag is fixed to the metal sleeve by a clamp at the edge. The gas injection connector is connected by a pipeline and is responsible for injecting gas into the airbag. An external pressure gauge is connected to measure the internal gas pressure in real time. Side foundation pit modules are set on both sides of the model test box structure. The side foundation pit modules include a diaphragm wall simulation device, which uses a 20mm thick PE board to simulate the diaphragm wall.

[0012] In the aforementioned model test device, active external pressure control systems for tunnels are installed vertically on opposite sides of the tunnel deformation area, and active external pressure control systems for tunnels are installed horizontally below the tunnel deformation area.

[0013] In the above-mentioned model test device, the drill rod is a segmented structure, and the adjacent two segments of the drill rod are connected by threads to connect the segments of the drill rod into a whole. Each segment of the drill rod is fixed with a deformable body. The gas injection connector is led out from the air bladder end of the deformable body, and the gas injection connectors between adjacent air bladders are connected by connecting pipes to connect the air bladders in series. The air bladder at the starting end is equipped with an air injection system.

[0014] In the above-mentioned model test device, an installation sleeve is installed on the gas injection connector or connecting pipe, and a burst valve is installed on the installation sleeve.

[0015] Furthermore, in order to facilitate the control of the pressure during active jacking and the lifting amplitude, a pressure gauge can be placed on the upper part of the jack to measure the changes in jacking pressure and displacement.

[0016] Furthermore, aramid fiber cloth can be used for reinforcement of the tensile zone of both the arch and the bottom of tunnel segments;

[0017] Furthermore, in order to prevent the epoxy resin on the inner surface of the tunnel from accidentally sticking to the curved plate lifting frame, a layer of polytetrafluoroethylene plastic film is placed between the aramid fiber cloth and the curved plate lifting frame to serve as an isolation function.

[0018] Furthermore, the aramid fiber cloth is lifted by jacks on the arc-shaped lifting frame and the arc-shaped base frame to ensure localized internal pressure lifting and simultaneous bonding of the aramid fiber cloth for a more secure result.

[0019] Furthermore, in order to facilitate observation of the soil pressure on the shield tunnel segments under the action of internal pressure jacking, multiple soil pressure cells were placed around the segments to measure the confining pressure.

[0020] Furthermore, in order to facilitate the measurement of segment displacement, displacement gauges are installed inside the segments to measure the changes in vertical and lateral convergence during the internal jacking process of the segments. At the same time, the active control of the airbag on the segments during the expansion process can also be measured.

[0021] Furthermore, based on the displacement changes of the tunnel segments, multiple airbags can be connected in series or parallel to play a role in active compensation and control.

[0022] This invention also provides a test method for an autonomous control model test device utilizing shield tunnel deformation, comprising the following steps:

[0023] 1) Lay a soil layer in the model test box up to the opening of the plexiglass, then put the assembled elliptical shield tunnel segments into the soil box, fill it with soil layer with a height equal to the tunnel diameter, and compact it.

[0024] 2) Install the tunnel active internal pressure regulation composite reinforcement system inside the shield tunnel segment and start the tunnel active internal pressure regulation composite reinforcement system to repair the elliptic deformation of the shield tunnel segment;

[0025] 3) Drill the tunnel active external pressure control system horizontally below the outside of the tunnel and inflate the airbags inside the tunnel active external pressure control system. The tunnel will be lifted to the predetermined position through the tunnel active external pressure control system below. Elliptical tunnels are generally accompanied by sinking. This step is used to lift the tunnel to the original position.

[0026] 4) Vertically drill into the tunnel active external pressure control system on both sides of the tunnel exterior, and inflate the airbags in the tunnel active external pressure control system. After the shield tunnel segments are reset by the tunnel active external pressure control system on both sides, the voids generated on both sides of the shield tunnel segments are filled.

[0027] The specific usage methods of the tunnel active internal pressure regulation composite reinforcement system and the tunnel active external pressure regulation system in the above-mentioned test methods are as follows:

[0028] The arc-shaped base frame and arc-shaped lifting frame are placed inside the shield lining. The outer arc surfaces of the arc-shaped lifting frame and arc-shaped base frame are respectively placed on the inner surfaces of the upper and lower shield segments. Jacks are vertically installed between the arc-shaped lifting frame and arc-shaped base frame. Aramid fiber cloth with epoxy resin is placed on the outer arc surface of the arc-shaped lifting frame and / or arc-shaped base frame.

[0029] Start the jacking operation, and use the arc-shaped jacking frame and / or arc-shaped base frame to attach the aramid fiber cloth to the inner surface of the shield tunnel segment. At the same time, control the jacking force to restore the elliptical shield tunnel segment to a perfect circle or to lift it to the designated position of the shield tunnel segment.

[0030] The tunnel active external pressure control system is drilled laterally below the outside of the tunnel. Specifically, the end of the drill rod is driven to drill laterally from the direction of the diaphragm wall hole into the designated position below the shield segment, so that the airbag reaches the predetermined position that needs to be actively lifted; the airbag is inflated to lift the settled shield segment, and the lifting amount is actively controlled by controlling the inflation amount.

[0031] Using the same method described above, the tunnel active external pressure control system 3 is drilled vertically into the opposite sides of the tunnel exterior, and the airbags on both sides are inflated. During the shield segment repositioning process, while voids are generated on both sides, the airbags on both sides squeeze the soil to fill the voids, ensuring the stability of the external support environment during and after the tunnel repair process.

[0032] In the side pit simulation module, multiple earth pressure cells are set up from top to bottom to measure the pressure changes in the soil.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The present invention adopts a method of active control both inside and outside the tunnel segment, which ensures that the aramid fiber cloth and the tunnel being repaired are firmly bonded under continuous pressure stabilization. The fixing of the aramid fiber cloth and the tunnel repair are completed simultaneously, eliminating the need to repair the tunnel first and then paste the aramid fiber cloth, thus saving manpower, material resources and time. It has the characteristics of being adjustable, stabilizing pressure and ensuring adhesion, and has broad application prospects.

[0035] (2) By using the integrated design of drilling rig and air bag, the traditional design of air bag and drill rod is changed. The front end of the drill rod is responsible for drilling, and the air bag is inflated by setting an air inlet pipe on the sleeve of the air bag. This achieves the goal of actively adjusting the soil displacement in one drilling operation, changing the original multi-step operation mode of drilling first, then removing the drill rod, and then placing the air bag.

[0036] (3) The present invention connects the airbag to the drill pipe body by means of a sleeve connection, and different airbag positions can be set or adjusted according to different geological conditions to achieve different control effects.

[0037] (4) In this invention, the height of the jack can be adjusted according to the requirements of the test lifting height. By adjusting the position of the jack, the jack can apply force to the vertical axis of the segment, ensuring uniform lifting.

[0038] (5) The present invention simulates the foundation pit on the side. By setting up the diaphragm wall, it is possible for the drilling rig to drill through the hole in the diaphragm wall, which changes the way of drilling long distances from the ground, shortens the construction distance, and makes the positioning more accurate.

[0039] (6) The arch bottom of the tunnel segment of the present invention can also be reinforced with aramid fiber cloth, and at the same time, the arch top and arch bottom of the tunnel segment can be repaired and reinforced simultaneously.

[0040] (7) The model test box in this invention is easy to assemble and disassemble, and can be modified according to the specific requirements of the test. It has multiple functions and is suitable for research on different geological conditions. In addition, it can carry out various geotechnical tests related to shield tunnel repair and reinforcement, karst cave filling, and bag grouting under different working conditions. Attached Figure Description

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0042] Figure 1 This is a front view of the model test device for shield tunnel lining in Embodiment 1 of the present invention;

[0043] Figure 2 This is a three-dimensional schematic diagram of the model test chamber structure in Embodiment 1 of the present invention;

[0044] Figure 3 This is a schematic diagram of the active control system for shield tunnel lining in Embodiment 1 of the present invention;

[0045] Figure 4 This is a schematic diagram of the active internal pressure control device for shield tunnels in Embodiment 1 of the present invention;

[0046] Figure 5 This is a schematic diagram of the tunnel active external pressure control system in Embodiment 1 of the present invention;

[0047] Figure 6 This is a detailed schematic diagram of the tunnel active external pressure regulating airbag in Embodiment 1 of the present invention;

[0048] Figure 7 This is a schematic diagram of the shield tunnel side foundation pit module in Embodiment 1 of the present invention;

[0049] Figure 8 This is a schematic diagram of the stratigraphic morphology changes in Embodiment 1 of the present invention;

[0050] Figure 9 This is a schematic diagram of Embodiment 3 of the present invention.

[0051] In the diagram: 1—Model test box structure; 2—Tunnel active internal pressure control composite reinforcement system; 3—Tunnel active external pressure control system; 4—Side pit module; 11—Intermediate column; 12—Corner column; 13—Side channel steel; 14—Transverse channel steel; 15—Acrylic glass panel; 20—Pressure gauge; 21—Shield tunnel segment (shield tunnel lining); 22—Aramid fiber cloth; 23—Arched jacking frame; 24—Jack; 25—Limiting and fixing seat; 26—Arched base frame; 27—Epoxy resin; 28—Arched plate of the arc-shaped jacking frame; 29—Rib plate; 30—Deformable body; 31—Drill bit; 32—Connection Drill rod; 33—Airbag; 34—Connecting pipe; 35—Pressure gauge; 36—Gas injection connector; 37—Clamp; 38—Explosive valve; 39—Installation sleeve; 41—Foundation pit; 42—Diaphragm wall; 43—Circular hole; 61—Cave; 71—Surface stratum line before internal pressure jacking; 72—Surface stratum line after internal pressure jacking; 73—Tunnel before internal pressure jacking; 74—Tunnel after internal pressure jacking; 75—Tunnel arch stratum line before internal pressure jacking; 76—Tunnel arch stratum line after internal pressure jacking; 77—Tunnel arch bottom stratum line before internal pressure jacking; 78—Tunnel arch bottom stratum line after internal pressure jacking; 79—Earth pressure box. Detailed Implementation

[0052] Example 1

[0053] like Figure 1As shown, a model test device for autonomous control of shield tunnels includes a model test box structure 1, a tunnel active internal pressure control composite reinforcement system 2, a tunnel active external pressure control system 3, and a side pit module 4.

[0054] like Figure 2 The model test chamber structure 1 shown is formed into a cuboid structure by a fully transparent plexiglass panel 15. The front and rear panels each have round holes that match the shield tunnel segments 21. The outer perimeter is constructed by assembling a steel frame. The central column 11 and corner column 12 are arranged vertically, the channel steel 14 is arranged horizontally, and the side channel steel 13 is arranged horizontally. The channel steels are connected by high-strength bolts, which facilitates the adjustment of the size of the model test chamber according to the test requirements.

[0055] like Figure 3 As shown, in the active control module 2 for shield tunnel lining, there are shield segments 21 that have become elliptical in the strata. The shield segments can be restored to a standard circular tunnel shape using an arc-shaped lifting frame 23 and an arc-shaped base frame 26 under the lifting action of jacks 24. As shown in the figure, the arc-shaped lifting frame 23 and the arc-shaped base frame 26 are fixedly connected at the top and bottom by high-strength bolts to prevent the arc-shaped lifting frame 23 from becoming unstable.

[0056] like Figure 4 As shown, the outer surface of the aramid fiber cloth 22 is evenly coated with epoxy resin adhesive 27 for tunnel reinforcement, and laid flat on the outer surface of the arc plate 28 of the arc-shaped jacking frame. To prevent the epoxy resin adhering the aramid fiber cloth 22 to the inner surface of the tunnel from accidentally adhering to the arc plate jacking frame 23, a layer of polytetrafluoroethylene plastic film is placed between the aramid fiber cloth and the arc plate jacking frame for isolation. During the jacking process of the jack 24, the force is transmitted to the inner surface of the fiber cloth and the tunnel segment through the rib plate 29, ensuring local internal pressure jacking and simultaneous adhesion of the aramid fiber cloth 22, making the adhesion and bonding more secure. This method differs from the traditional method of jacking first and then adhering, solving the problem of how to effectively improve the adhesion effect of the fiber cloth. As a flexible reinforcement material, the aramid fiber cloth 22 has extremely high tensile strength. Using it for reinforcement of the tensile areas of concrete is easy to construct, fast in reinforcement speed, and can improve the strength of the shield tunnel segment.

[0057] like Figure 5 and Figure 6The diagram shows a schematic of the tunnel active external pressure control system 3. In this embodiment, the tunnel active external pressure control system 3 is located 1D below the tunnel. The tunnel active external pressure control system 3 includes a drill bit 31 and a drill rod 32 with one end connected to the drill bit 31. Multiple deformable bodies 30 are fixed along the length of the drill rod 32. Each deformable body 30 includes an air bladder 33 equipped with an air injection system. A power source is matched to the tail end of the drill rod 34. The drill bit 31 drills in the soil under the power provided. The deformable bodies 30 are fixed to the outside of the drill rod 34 by a metal sleeve. The air bladder 33 is fixed to the metal sleeve at the edge by a clamp 37. The gas injection connector 36 is connected by a pipeline and is responsible for injecting gas into the air bladder 33. An external pressure gauge is connected to measure the internal gas pressure in real time. The drill rod 32 adopts a segmented structure. The adjacent two segments of the drill rod 32 are connected by threads to connect the segments of the drill rod 32 into a whole. Each segment of the drill rod 32 is fixed with a deformable body 30. Gas injection connectors 36 are led out from the ends of airbags 33, and the gas injection connectors 36 between adjacent airbags 33 are connected by connecting pipes 34 to connect the airbags 33 in series. The airbag 33 at the starting end is equipped with an air injection system. An installation sleeve 39 is installed on the gas injection connector 36 or the connecting pipe 34. The installation sleeve 39 can be welded to the deformable body 30. A burst valve 38 is installed in the middle of the installation sleeve 39. The burst pressure of the burst valve 38 is related to the pressure of the airbag 33. The burst valve 38 can only burst when the airbag 33 is completely filled with gas to achieve the target of controlling soil displacement, and the higher the pressure, the better, but it cannot exceed the pressure at which the airbag 33 bursts. The function of the burst valve 38 is that after the previous airbag 33 is filled and reaches the set pressure, the burst valve 38 opens and sends gas to the next airbag 33 through the connecting pipe 34 to inflate the next airbag 33. This process is repeated to inflate the airbags 33 connected in series, so that the deformable body 30 expands one by one and squeezes the surrounding soil.

[0058] like Figure 7 As shown, the lateral foundation pit simulation module 4 is located inside the outer frame and on the side of the shield tunnel segment 21. The lateral foundation pit simulation module 4 divides the soil into two parts via a diaphragm wall 42: the left side is the main test section, and the right side is the foundation pit 41 section. A slot 43 (hole) is cut into the lower part of the diaphragm wall 42 to facilitate the operation of the tunnel active external pressure control system 3. The diaphragm wall 42 is fixed by being embedded in an acrylic panel 15 via a slot. The diaphragm wall 42 is made of 20mm thick PE sheet. Three isolation supports 44 are installed on the side of the foundation pit to ensure the safety of the foundation pit support.

[0059] like Figure 8As shown, this invention mainly addresses the changes in strata morphology caused by the new active repair and reinforcement method for elliptical tunnels. Before the local internal pressure jacking, the stratum line 71 was "V" shaped. After the internal pressure jacking deformation, the surface line 72 was almost horizontal. Before loading, the tunnel 73, constructed by the shield tunnel segments 21, was elliptical. After the internal pressure jacking deformation, it became a circular tunnel 74. The original soil layer 75 above the tunnel became a deformed soil layer 76. Similarly, under the action of the tunnel active external pressure control system 3, the soil layer at the bottom of the tunnel changed from the original soil layer 77 to the subsequent soil layer 78. Multiple earth pressure boxes 79 were set up to facilitate understanding the pressure changes of the soil after the active control method was adopted.

[0060] The test method using the aforementioned autonomous control model test device for shield tunnel deformation includes the following steps:

[0061] 1) Lay a soil layer in the model test box 1 up to the opening of the plexiglass, then put the assembled elliptical shield tunnel segment 21 into the soil box, fill it with soil layer with a height equal to the tunnel diameter, and compact it.

[0062] 2) Install the tunnel active internal pressure regulation composite reinforcement system 2 inside the shield segment 21, and start the tunnel active internal pressure regulation composite reinforcement system 2 to repair the elliptic deformation of the shield segment 21.

[0063] 3) Drill the tunnel active external pressure control system 3 horizontally below the outside of the tunnel and inflate the airbag 33 inside the tunnel active external pressure control system 3. The tunnel is then lifted to the predetermined position through the tunnel active external pressure control system 3 below. Elliptical tunnels are generally accompanied by sinking. This step is used to lift the tunnel to the original position.

[0064] Specifically, the arc-shaped base frame 26 and the arc-shaped lifting frame 23 are placed inside the shield lining. The outer arc surfaces of the arc-shaped lifting frame 23 and the arc-shaped base frame 26 are respectively placed on the inner surfaces of the upper and lower shield segments 21. A jack 24 is vertically placed between the arc-shaped lifting frame 23 and the arc-shaped base frame 26. The aramid fiber cloth 22 with epoxy resin 27 is placed on the outer arc surfaces of the arc-shaped lifting frame 23 and / or the arc-shaped base frame 26.

[0065] Start the jack 24 to carry out the lifting work. Relying on the arc-shaped lifting frame 23 and / or arc-shaped base frame 26, the aramid fiber cloth 22 is pasted onto the inner surface of the shield tunnel segment 21. At the same time, control the lifting force of the jack 24 so that the elliptical shield tunnel segment 21 is restored to a perfect circle or lifted to the designated position of the shield tunnel segment 21.

[0066] The tunnel active external pressure control system 3 is drilled laterally below the outside of the tunnel. Specifically, the end of the drive rod 32 is driven to drill laterally from the direction of the hole left in the diaphragm wall 42 to a designated position below the shield segment 21 through the drill bit 31, so that the airbag 33 reaches the predetermined position that needs to be actively lifted; the airbag 33 is inflated to lift the settled shield segment 21, and the lifting amount is actively controlled by controlling the inflation amount.

[0067] In the side foundation pit simulation module, multiple earth pressure cells 79 are set up from top to bottom to measure the pressure changes in the soil.

[0068] Example 2

[0069] The difference between this embodiment and embodiment 1 is that the tunnel active external pressure control system 3 in this embodiment also uses vertical drilling to control soil displacement, so as to fill the soil voids on both sides of the shield segment 21. Based on this idea, the shield segment 21 can be elliptical in any direction, and this method can be used to fill and compact the local soil voids. In this embodiment, the tunnel active external pressure control system 3 is drilled vertically into both sides of the tunnel, and the soil on both sides of the shield segment 21 is squeezed by inflating the airbags, so that the voids generated on both sides during the process of the shield segment 21 returning to a circular shape are filled and compacted.

[0070] Example 3

[0071] like Figure 9 As shown, the difference between this embodiment and embodiment 1 is that the tunnel active external pressure control system 3 in this embodiment also uses vertical drilling to control the soil displacement in order to achieve the effect of actively controlling the overall displacement of the shield segment 21. Based on this idea, the shield segment 21 can be locally actively controlled if it undergoes elliptic deformation in any direction. In this embodiment, the tunnel active external pressure control system 3 is drilled vertically into the right side of the tunnel diagram, and the shield segment 21 is squeezed by inflating the airbag to make the shield segment 21 move to the left, or to squeeze the soil on the right side of the shield segment 21 to fill and compact the void generated on the right side of the shield segment 21.

[0072] It should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all the features of the foregoingly disclosed embodiments. Therefore, the claims, following the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

Claims

1. A self-regulating model test device for the deformation of a shield tunnel, comprising a model test box structure (1), wherein the model test box structure (1) is an outer frame formed by channel steel (13) and corner columns (12), and the interior is a cuboid structure enclosed by plexiglass panels; characterized in that: It also includes a tunnel active internal pressure control composite reinforcement system (2) and a tunnel active external pressure control system (3); The tunnel active internal pressure regulation composite reinforcement system (2) includes an arc-shaped base frame (26), jacks (24), an arc-shaped jacking frame (23), and aramid fiber cloth (22). The outer arc surfaces of the arc-shaped jacking frame (23) and the arc-shaped base frame (26) are respectively mounted on the inner surfaces of the upper and lower shield segments (21). A jack (24) for jacking is placed between the arc-shaped jacking frame (23) and the arc-shaped base frame (26). Aramid fiber cloth (22) is laid on the outer arc surfaces of the arc-shaped base frame (26) and / or the arc-shaped jacking frame (23). The tunnel active external pressure control system (3) includes a drill bit (31) and a drill rod (32) with one end connected to the drill bit (31). Multiple deformable bodies (30) are fixed along the length direction on the drill rod (32). The deformable body (30) includes an airbag (33) equipped with an air injection system. The tunnel active internal pressure regulation composite reinforcement system (2) is installed inside the tunnel, and the tunnel active external pressure regulation system (3) is installed on the side and / or below the outside of the tunnel; The drill rod (32) is a segmented structure. The adjacent two segments of the drill rod (32) are connected by threads to connect the segmented drill rod (32) into a whole. Each segment of the drill rod (32) is fixed with a deformable body (30). The gas injection connector (36) is led out from the end of the air bladder (33) of the deformable body (30). The gas injection connector (36) between adjacent air bladders (33) is connected by a connecting pipe (34) to connect the air bladders (33) in series. The air bladder (33) at the beginning end is equipped with an air injection system. The test method includes the following steps: 1) Lay a soil layer in the model test box structure (1) up to the opening of the plexiglass, then put the assembled elliptical shield tunnel segment (21) into the soil box, fill it with a soil layer of 1 times the tunnel diameter height, and compact it. 2) The active internal pressure regulation composite reinforcement system (2) is installed inside the shield segment (21), and the active internal pressure regulation composite reinforcement system (2) is activated to repair the elliptic deformation of the shield segment (21); 3) Drill into the tunnel active external pressure control system (3) horizontally below the outside of the tunnel and inflate the airbag (33) inside the tunnel active external pressure control system (3) to lift the tunnel to the predetermined position through the tunnel active external pressure control system (3) below. 4) The tunnel active external pressure control system (3) is drilled vertically on both sides of the tunnel exterior and the airbag (33) inside the tunnel active external pressure control system (3) is inflated. After the shield segment (21) is reset by the tunnel active external pressure control system (3) on both sides, the void generated on both sides of the shield segment (21) is filled.

2. The autonomous control model test device for shield tunnel deformation according to claim 1, characterized in that: Tunnel active external pressure control system (3) is installed vertically on both sides of the outside of the tunnel deformation point, and tunnel active external pressure control system (3) is installed horizontally below the outside of the tunnel deformation point.

3. The autonomous control model test device for shield tunnel deformation according to claim 1, characterized in that: An installation sleeve (39) is installed on the gas injection connector (36) or connecting pipe (34), and a burst valve (38) is installed on the installation sleeve (39).

4. The autonomous control model test device for shield tunnel deformation according to claim 1, characterized in that: Multiple earth pressure cells (79) are placed around the tunnel segments inside the model test chamber structure (1) to measure the tunnel confining pressure.

5. The autonomous control model test device for shield tunnel deformation according to claim 1, characterized in that: The lower surface of the arc-shaped lifting frame (23) and the upper surface of the arc-shaped base frame (26) are both lifting planes. The jack (24) is located between the two lifting planes. Two jacks (24) of the same type are distributed between the two lifting planes. Their force is to lift synchronously and prevent the arc-shaped lifting frame (23) from tipping over.

6. The autonomous control model test device for shield tunnel deformation according to claim 1, characterized in that: The upper end of the arc-shaped base frame (26) is provided with a jack limiting and fixing seat (25), and the base of the jack (24) is placed on the jack limiting and fixing seat (25); a pressure gauge (20) is added to the upper part of the jack (24).

7. The autonomous control model test device for shield tunnel deformation according to claim 1, characterized in that: A layer of polytetrafluoroethylene plastic film is placed between the aramid fiber cloth (22) and the arc-shaped lifting frame (23).

8. The autonomous control model test device for shield tunnel deformation according to claim 1, characterized in that, The specific usage methods of the tunnel active internal pressure regulation composite reinforcement system (2) and the tunnel active external pressure regulation system (3) are as follows: The arc-shaped base frame (26) and the arc-shaped jacking frame (23) are placed inside the shield lining. The outer arc surfaces of the arc-shaped jacking frame (23) and the arc-shaped base frame (26) are respectively placed on the inner surfaces of the upper and lower shield segments (21). A jack (24) is placed vertically between the arc-shaped jacking frame (23) and the arc-shaped base frame (26). The aramid fiber cloth (22) with epoxy resin (27) is placed on the outer arc surfaces of the arc-shaped jacking frame (23) and / or the arc-shaped base frame (26). Start the jack (24) to carry out the lifting work. Relying on the arc-shaped lifting frame (23) and / or arc-shaped base frame (26), the aramid fiber cloth (22) is pasted on the inner surface of the shield tunnel segment (21). At the same time, control the lifting force of the jack (24) so ​​that the elliptical shield tunnel segment (21) is restored to a perfect circle or lifted to the designated position of the shield tunnel segment (21). The active external pressure control system (3) is drilled horizontally below the outside of the tunnel. Specifically, the end of the drive rod (32) is driven to drill horizontally from the direction of the hole left in the diaphragm wall (42) to the designated position below the shield segment (21), so that the airbag (33) reaches the predetermined position that needs to be actively lifted; the airbag (33) is inflated to lift the settled shield segment (21), and the lifting amount is actively controlled by controlling the inflation amount. Using the same method described above, the tunnel active external pressure control system (3) is drilled vertically into the opposite sides of the tunnel exterior, and the airbags (33) on both sides are inflated. During the reset of the shield segment (21), while the external area on both sides is empty, the airbags (33) on both sides squeeze the soil to fill the empty area, ensuring the stability of the external support environment during and after the tunnel repair process. Multiple earth pressure cells (79) are set up from top to bottom in the side pit simulation module to measure the pressure changes of the soil.

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