A tunnel shield excavation simulation experiment device, experiment system and experiment method

Abstract

The present application belongs to the technical field of tunnel construction simulation, and relates to tunnel model shield excavation simulation, in particular to a tunnel shield excavation simulation experiment device, an experiment system and an experiment method. The tunnel shield excavation simulation experiment device and the related experiment method proposed by the present application adopt a magnetic assembly type shield segment assembly and an excavation simulation piece capable of injecting and discharging fluid to cooperate, can realize step-by-step excavation and automatic support process simulation under limited conditions by using the change trend of the cross section area in the lumen drainage process, truly restores the segment unfolding, assembling and stress transmission path in the shield method construction process, has real and reliable simulation effect, and increases the reliability of the guidance to the actual engineering. The whole tunnel shield excavation simulation experiment device has simple structure and low cost, the shield segment is automatically closed by magnetic attraction of the magnetic attraction piece, greatly simplifies the experiment process, significantly improves the automation degree and repeatability of the experiment, and has good economy and practicability.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction simulation technology, and relates to tunnel model shield excavation simulation, and in particular to a tunnel shield excavation simulation experimental device, experimental system and experimental method. Background Technology

[0002] Shield tunneling technology boasts advantages such as high mechanization, relatively safe construction, and minimal disturbance to the surrounding environment, and is now widely used in urban rail transit, underground utility tunnels, and hydraulic tunnels. In shield tunnel construction, the splicing and installation of tunnel segments is a crucial step in structural formation, and its quality and process directly affect structural stability and surrounding rock disturbance. Existing model experiments often simulate tunnel excavation by pulling and retracting pre-embedded pipes. However, in shield tunneling connecting passage construction, limitations imposed by existing structures and boundary conditions prevent simulation of shield construction through this method. Furthermore, model experiments often use fixed assembly methods for tunnel segments, lacking simulation of the actual installation process and failing to accurately reproduce the segment deployment, assembly, and stress transmission paths. Consequently, it is difficult to obtain dynamic response data to the surrounding rock and support system during segment installation. Therefore, there is an urgent need to develop a novel shield tunneling simulation experimental device to improve the realism of the segment installation process during shield tunneling, accurately reproducing the segment deployment, assembly, and stress transmission paths to overcome the shortcomings of existing technologies. Summary of the Invention

[0003] The purpose of this invention is to provide a tunnel shield excavation simulation experimental device, experimental system and experimental method, which can realistically simulate the tunnel distributed excavation and support process, and realistically reproduce the segment deployment, assembly and force transmission path during shield tunneling construction, so as to solve the problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides the following solution: This invention provides a tunnel shield excavation simulation experimental device, comprising a shield segment assembly, a connecting assembly, and an excavation simulation component, wherein: The excavation simulation component includes a deformable cavity for injecting and draining fluid and a fluid injection and draining control assembly. One end of the deformable cavity is closed and the other end is provided with an opening. The fluid injection and draining control assembly is connected to the opening and is used to inject and drain fluid into the deformable cavity. The shield tunnel segment assembly includes multiple arc-shaped shield tunnel segments arranged in a ring, and each arc-shaped shield tunnel segment is used to be sleeved on the outside of the deformable cavity along the axial direction of the deformable cavity. The connecting component includes a magnetic suction component one and a magnetic suction component two that can magnetically attract the magnetic suction component one. The magnetic suction component one and the magnetic suction component two are respectively disposed at the two adjacent ends of two curved shield tunnel segments. Any two adjacent curved shield tunnel segments can be automatically magnetically assembled by the connecting component during the drainage process of the deformable cavity.

[0005] In some embodiments, the fluid injection / discharge control assembly includes an injection / discharge line and a control valve disposed on the injection / discharge line, the injection / discharge line being sealed to the opening of the deformable cavity.

[0006] In some embodiments, the fluid injection / discharge control assembly further includes a flow controller disposed on the injection / discharge line.

[0007] In some embodiments, the deformable lumen expands into a cylindrical lumen; the material of the deformable lumen is rubber, silicone, or latex.

[0008] In some embodiments, the shield tunnel segment assembly includes two arc-shaped shield tunnel segments, namely a first arc-shaped shield tunnel segment and a second arc-shaped shield tunnel segment, both of which are semi-circular segments.

[0009] In some embodiments, the first arc-shaped shield tunnel segment is formed by hinged two quarter-arc segments; one of the magnetic attraction element one and the magnetic attraction element two is respectively provided at the far ends of the two quarter-arc segments.

[0010] In some embodiments, the first magnetic attractor and the second magnetic attractor are respectively an N-pole magnet and an S-pole magnet.

[0011] The present invention also proposes a tunnel shield excavation simulation experimental system, including experimental soil, a model box, and a tunnel shield excavation simulation experimental device as described above; the experimental soil is filled in the model box, and the tunnel shield excavation simulation experimental device is set in the experimental soil so as to apply confining pressure to the outer periphery of the tunnel shield excavation simulation experimental device through the experimental soil.

[0012] In some embodiments, the experimental soil is a transparent experimental soil prepared from n-dodecane, white oil and fumed silica; or, the experimental soil is a soil prepared from barite powder, talc powder, gypsum and water in a specific ratio. The experimental soil was formed by layering soil materials in the model box.

[0013] This invention also proposes a method for simulating tunnel shield excavation, implemented using the tunnel shield excavation simulation system described above, comprising: Multiple shield tunnel segment assemblies are arranged along the axial direction of the deformable cavity to the outside of the deformable cavity that has been filled with fluid, thus completing the assembly of the tunnel shield excavation simulation experimental device; The experimental soil is poured into the model box, and the tunnel shield excavation simulation experimental device is placed in the pouring process; after the experimental soil is poured, the experimental soil is distributed around the outer periphery of the tunnel shield excavation simulation experimental device so as to apply pressure to the outer periphery of each shield segment assembly using the experimental soil. The fluid injection and discharge control component controls the fluid in the deformable cavity to be discharged at a set flow rate until each shield tunnel segment assembly gradually contracts under the action of the experimental soil along the shield tunneling direction and automatically closes magnetically, completing the segment assembly and simulating the soil distribution excavation and automatic support process.

[0014] The present invention achieves the following technical effects compared to the prior art: The tunnel shield excavation simulation experimental device and related experimental methods proposed in this invention, when applied to the scaled-down model experiment of the connecting passage, can effectively simulate the shield construction process. They not only have the advantages of minimal limitations, ease of operation, and low cost, but also provide accurate experimental results. Specific beneficial effects are as follows: (1) In the construction of the shield tunnel connecting passage, due to the limitations of the existing tunnel and model boundary conditions, it is impossible to simulate the shield tunnel construction by pulling the pre-embedded pipe in the traditional model experiment. In addition, the traditional model experiment fixes the segments as a whole, which cannot simulate the segment installation of shield construction. The above-mentioned experimental device and experimental method of this scheme adopts the combination of magnetically assembled shield segment components and excavation simulation components that can inject and drain fluid. It can realize the simulation of the step-by-step excavation and automatic support process under limited conditions by utilizing the changing trend of cross-sectional area during the drainage of fluid in the cavity. It truly restores the segment unfolding, assembly and force transmission path in the shield construction process. The simulation effect is realistic and reliable, which increases the reliability of guidance for actual projects.

[0015] (2) After the tunnel segment structure of each shield tunnel segment assembly radially shrinks (i.e. the cross-sectional area decreases due to the drainage), it rotates around the pin shaft under the pressure of the surrounding experimental soil and automatically closes through the magnetic attraction component, which greatly simplifies the experimental process and significantly improves the automation and repeatability of the experiment.

[0016] (3) The entire tunnel shield excavation simulation experimental device has a simple structure, low cost, and can be reused, and has good economic efficiency and practicality.

[0017] The complete tunnel shield excavation simulation test system includes the aforementioned complete tunnel shield excavation simulation test device and possesses all the features of the aforementioned complete tunnel shield excavation simulation test device, which will not be repeated here. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the tunnel shield excavation simulation experimental system disclosed in an embodiment of the present invention; Figure 2 This is a schematic diagram of the experimental process of the tunnel shield excavation simulation experimental device disclosed in an embodiment of the present invention; Figure 3 This is a schematic diagram of the excavation simulation component in the tunnel shield excavation simulation experimental device disclosed in an embodiment of the present invention; Figure 4 This is a schematic diagram of the shield tunneling segment assembly in a disconnected state in the tunnel shield excavation simulation experimental device disclosed in an embodiment of the present invention; Figure 5 This is a schematic diagram of the shield tunnel segment assembly in a magnetically closed state in the tunnel shield excavation simulation experimental device disclosed in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the closing process of the shield tunnel segment assembly in the tunnel shield excavation simulation experimental device disclosed in an embodiment of the present invention. Figure 7 This is a schematic diagram of the structure of the hinge component in the shield tunnel segment assembly disclosed in an embodiment of the present invention; Figure 8 This is a schematic diagram of the engagement state of the connecting components in the shield tunnel segment assembly disclosed in an embodiment of the present invention.

[0020] In the figure, the reference numerals are: 100 - Tunnel shield excavation simulation experimental device; 200 - Tunnel shield excavation simulation experimental system; 300 - Model box; 400 - Experimental soil. 1-Shield tunnel segment assembly; 11-First arc-shaped shield tunnel segment; 12-Second arc-shaped shield tunnel segment; 13-Quarter arc-shaped segment; 14-Hinge joint; 15-Hinge; 16-Protrusion; 17-Notch; 2-Connecting component; 21-Magnetic component one; 22-Magnetic component two; 3-Excavation simulation component; 31-Deformable cavity; 311-Opening; 312-Tightening transition; 32-Injection and drainage pipeline; 33-Control valve. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] One of the objectives of this invention is to provide a tunnel shield excavation simulation experimental device that can realistically simulate the tunnel distribution excavation and support process, and accurately reproduce the segment deployment, assembly, and force transmission path during shield tunneling construction, thereby overcoming the shortcomings of existing technologies.

[0023] Another object of the present invention is to provide a tunnel shield excavation simulation experiment system including the above-mentioned tunnel shield excavation simulation experiment device.

[0024] Another objective of this invention is to provide a method for simulating tunnel shield excavation using the aforementioned tunnel shield excavation simulation experimental system.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1 like Figures 1-8As shown in the figure, this embodiment provides a tunnel shield excavation simulation experimental device 100, which is mainly used to simulate the distributed excavation and support process. It includes a shield segment assembly 1, a connecting assembly 2, and an excavation simulation component 3. The shield tunnel segment assembly 1 includes multiple arc-shaped shield tunnel segments arranged in a ring, which together enclose a tunnel simulation space. Any two adjacent arc-shaped shield tunnel segments can be spliced ​​together by a connecting component 2. The connecting component 2 includes a magnetic suction component 21 and a magnetic suction component 22 that can magnetically attract the magnetic suction component 21. The magnetic suction component 21 and the magnetic suction component 22 are respectively set at the two close ends of the two adjacent arc-shaped shield tunnel segments. The excavation simulation component 3 includes a deformable cavity 31 for injecting and discharging fluid and a fluid injection and discharge control component. One end of the deformable cavity 31 is closed and the other end is provided with an opening 311. The fluid injection and discharge control component includes an injection and discharge pipeline 32 and a control valve 33 provided on the injection and discharge pipeline 32. The injection and discharge pipeline 32 is sealed to the opening 311 of the deformable cavity 31. The sealing connection method includes, but is not limited to, insertion, bonding, and integral molding. After the deformable cavity 31 is filled with fluid, the cavity expands into a columnar shape. At this time, the control valve 33 is closed to prevent fluid leakage. Then, the columnar deformable cavity 31 is inserted into the tunnel simulation space formed by the arc-shaped shield segments, so that any two adjacent arc-shaped shield segments are separated from each other under the radial support of the deformable cavity 31, and any arc-shaped shield segment is attached to the outer wall of the deformable cavity 31. During the experiment, multiple sets of shield tunnel segment assemblies 1 are arranged continuously or at intervals along the axial direction of the deformable cavity 31. When the experiment simulating the distributed excavation and support process needs to be started, the control valve 33 is opened to discharge the fluid in the deformable cavity 31 at a certain flow rate (this flow rate can be flexibly adjusted according to different situations). The cross-section of the deformable cavity 31 can be reduced in segments as the fluid is discharged to simulate the distributed excavation of the tunnel soil. The shield tunnel segment assemblies 1 located in the section with reduced cross-sectional area of ​​the cavity will converge and shrink under the action of the surrounding soil due to the reduced radial support force of the deformable cavity 31, until they are magnetically attracted by the connecting component 2 and assembled into a closed ring to support the tunnel soil. By gradually discharging the fluid in the cavity, the assembly of each shield tunnel segment assembly 1 on the outer wall of the cavity can be completed step by step, realizing the simulation of the distributed excavation and support process of the tunnel.

[0027] In some feasible implementations, the preferred fluid injection and discharge control assembly also includes a flow controller disposed on the injection and discharge pipeline 32. The flow controller works in conjunction with the control valve 33 to precisely control the flow rate of fluid discharged from the pipeline.

[0028] Before conducting the experiment, a fluid source can be connected through the injection / discharge line 32 to inject the corresponding fluid into the deformable cavity 31.

[0029] The fluid that can be injected into the deformable cavity 31 includes, but is not limited to, liquid fluid. In this embodiment, the fluid injected into the deformable cavity 31 is preferably a liquid fluid, such as water. After the deformable cavity 31 is filled with liquid, the support strength is higher than that of gas filling. The segmented transition of the cavity cross-section reduction process during liquid drainage is more detailed and reliable, which can accurately simulate the tunnel distribution excavation and support process.

[0030] In some feasible implementations, the deformable lumen 31 is preferably a cylindrical lumen with a circular or regular polygonal cross-section, such as a cylindrical lumen or a regular polygonal prism lumen. To ensure the continuity of the gradual change in the cross-section of the lumen, it is preferred that the lumen be cylindrical, that is, the lumen becomes a uniform cylindrical shape after liquid injection and expansion. The deformable lumen 31 is preferably made of a soft film lumen, such as a plastic film lumen or an elastic plastic lumen. The elastic plastic includes, but is not limited to, materials such as rubber, latex, and silicone.

[0031] The opening end of the deformable cavity 31 preferably adopts a tapering transition design to ensure the smoothness and reliability of the drainage process. At the same time, as the liquid in the deformable cavity 31 is discharged, there is a tapering transition 312 between the small section with a smaller cross-sectional area and the adjacent expansion section (i.e., the section whose cross-sectional area has not yet decreased), which ensures the gradual continuity and smoothness of the cavity cross-section along the tunneling direction.

[0032] The injection / discharge pipeline 32 may include, but is not limited to, rubber hoses, rigid plastic tubes, or metal tubes. Taking a rubber hose as an example, the hose is sealed to one end opening 311 of the cylindrical cavity to allow for the injection and discharge of liquid within the cylindrical cavity. The control valve 33 may be a solenoid valve or a manual valve, and it is preferably located near the opening 311 of the cylindrical cavity in the injection / discharge pipeline 32 to facilitate control of the fluid pressure inside the cavity, thereby ensuring the accuracy and reliability of the experimental simulation.

[0033] In some feasible implementations, the preferred shield segment assembly 1 includes only two arc-shaped shield segments, namely a first arc-shaped shield segment 11 and a second arc-shaped shield segment 12. The first arc-shaped shield segment 11 and the second arc-shaped shield segment 12 are two identical semi-circular segments, which can form a closed shield ring after their ends are sucked together.

[0034] In some feasible implementations, any arc-shaped shield tunnel segment can be an integral segment structure or an assembled segment structure with a hinge joint 14. To avoid stress concentration problems in the segments, it is preferable that any arc-shaped shield tunnel segment is formed by hinged two quarter-arc segments 13, that is, each arc-shaped shield tunnel segment has a hinge joint 14 in the middle, which can improve the pressure resistance of the arc-shaped shield tunnel segment. Taking the first arc-shaped shield tunnel segment 11 as an example, it includes two quarter-arc segments 13. The two quarter-arc segments 13 are hinged together at their close ends by a hinge member 15 to form a hinge joint 14. The two quarter-arc segments 13 are respectively provided with one of a magnetic attraction member 21 and a magnetic attraction member 22 at their far ends.

[0035] In some feasible implementations, the hinge 15 includes, but is not limited to, the use of a pin. Two quarter-arc segments 13 located in the same arc-shaped shield tunnel segment are provided with protrusions 16 and recesses 17 that are adapted to fit the protrusions 16 at their respective close ends. Pin holes are provided on both sides of the protrusions 16 and the recesses 17. The two quarter-arc segments 13 are connected by fitting the protrusions 16 and recesses 17 into place. After insertion, the pin holes on the protrusions 16 and recesses 17 are aligned. Then, the pin is inserted into the pin holes on the protrusions 16 and recesses 17, thus achieving the hinge between the two quarter-arc segments 13 in the same arc-shaped shield tunnel segment. The pin is located at the joint of the two quarter-arc segments 13, and each quarter-arc segment 13 can rotate freely around the pin. In the same arc-shaped shield tunnel segment, two quarter-arc segments 13 are connected by a protrusion 16 and a notch 17, which can avoid relative axial movement between the two quarter-arc segments 13 during the experiment, thus ensuring the accuracy and reliability of the experiment.

[0036] Preferably, the protrusion 16 and the notch 17 are integrally formed with the corresponding quarter-arc tube 13 to improve the structural strength of the hinge joint 14.

[0037] In some feasible implementations, the pin and the corresponding pin hole are clearance-fitted. The specific structure of the pin includes, but is not limited to, rod-shaped structures such as round rods, screws, or bolts. Taking a round rod as an example, the corresponding pin hole is also a round hole. To improve the connection reliability between two quarter-arc segments 13 in the same arc-shaped shield tunnel segment, it is preferable to provide limiting protrusions at both ends of the pin to prevent the pin from slipping out of the pin hole. If the pin is a bolt, the head of the bolt can serve as a limiting protrusion at one end, and the limiting protrusion at the other end of the bolt can be achieved by connecting an adapter nut to the tail of the bolt.

[0038] The structure of the second arc-shaped shield segment 12 is completely identical to that of the first arc-shaped shield segment 11, and will not be described in detail here.

[0039] In some feasible implementations, the magnetic attractor 21 and magnetic attractor 22 of each connecting assembly 2 are N-pole magnets and S-pole magnets, respectively, and they are attracted based on the principle of attraction between opposite magnets. In the first arc-shaped shield tunnel segment 11, the magnetic attractors at the two far apart ends of the two quarter-arc segments 13 have the same polarity (both S-pole or both N-pole) or opposite polarity. The polarity of the magnetic attractors at both ends of the second arc-shaped shield tunnel segment 12 only needs to be opposite to the polarity of the corresponding magnetic attractors at the ends of the first arc-shaped shield tunnel segment 11. Taking the magnetic attractors at both ends of the first arc-shaped shield tunnel segment 11 as magnetic attractor 21 and magnetic attractor 22 as examples, the magnetic attractors at both ends of the second arc-shaped shield tunnel segment 12 are magnetic attractor 22 and magnetic attractor 21 as magnetic attractor 22.

[0040] In some feasible implementations, the second arc-shaped shield tunnel segment 12, the first arc-shaped shield tunnel segment 11, the magnetic chuck 1 21, and the magnetic chuck 22 are preferably all manufactured by 3D printing technology, which has the advantages of low cost, high production efficiency, and high product structural precision.

[0041] The radial cross-section of the first arc-shaped shield tunnel segment 11 is preferably rectangular. Correspondingly, the magnetic chuck 22 and magnetic chuck 21 are preferably rectangular magnets. Magnetic chuck 22 and magnetic chuck 21 can be directly bonded to the ends of the first arc-shaped shield tunnel segment 11, or mounting spaces for accommodating the magnetic chucks can be provided at both ends of the first arc-shaped shield tunnel segment 11. After the magnetic chucks are embedded in the mounting spaces at both ends of the first arc-shaped shield tunnel segment 11, they are then reinforced to the first arc-shaped shield tunnel segment 11 by adhesive or other means. In this design structure, it is preferable that the ends of the magnetic chucks are flush with the ends of the mounting spaces at the ends of the first arc-shaped shield tunnel segment 11. The arrangement of the magnetic chucks at both ends of the second arc-shaped shield tunnel segment 12 is the same as that of the first arc-shaped shield tunnel segment 11, and will not be described in detail here.

[0042] It should be noted that when the magnetic chuck is directly fixed to the end of the first arc-shaped shield tunnel segment 11, the common arc length of the two magnetic chucks plus the first arc-shaped shield tunnel segment 11 is a semi-circular arc length. When the magnetic chuck is directly fixed to the end of the second arc-shaped shield tunnel segment 12, the common arc length of the two magnetic chucks plus the second arc-shaped shield tunnel segment 12 is a semi-circular arc length.

[0043] When using a space-embedded magnetic component, it is preferable to reserve an installation space at the end of the quarter-arc segment 13 when printing the shield tunnel segment assembly 1 using 3D printing technology, so as to facilitate the subsequent installation of magnets.

[0044] The following example, using a cylindrical latex tube with one end sealed and the other end open (311) as an example, will specifically explain the usage, experimental principle, and technical effects of the above-mentioned tunnel shield excavation simulation experimental device 100: Step 1: Inject liquid into the deformable cavity 31 to the designed diameter to maintain the original shape and stress state before tunnel excavation. Multiple shield tunnel segment assemblies 1 are continuously arranged along the axial direction of the deformable cavity 31 to the outside of the cavity, with each shield tunnel segment assembly 1 arranged in a ring around the cavity. After covering the outside of the multiple shield tunnel segment assemblies 1 with a tubular latex membrane, the entire experimental device is placed into the experimental soil model, and experimental soil 400 is distributed around the periphery of the device to simulate the circumferential pressure exerted by the tunnel soil on the shield tunnel segment assemblies 1. Using a tubular latex membrane to cover the outside of the shield tunnel segment assemblies 1 reduces the friction between the shield tunnel segment assemblies 1 and the soil during tunnel excavation, preventing excessive friction from affecting the realism of the excavation and support simulation.

[0045] The experiment was designed based on the actual shield tunneling construction theory. After comprehensively considering the on-site engineering dimensions, measuring equipment, model type and materials, and fabrication conditions, the similarity ratio of each physical quantity in the model experiment was determined. Based on the similarity ratio, the target values ​​of the physical parameters of the model experimental soil 400 were determined, and soil with corresponding properties was prepared. The experimental soil 400 typically uses transparent experimental soil, prepared as follows: First, dodecane and white oil are fully mixed according to the formula. Then, fumed silica is added according to the formula and stirred evenly to form a transparent soil material. The transparent soil material is layered and filled into the model box 300, and a vacuum is drawn. The transparent soil is left to stand in a vacuum environment for one day to allow it to fully solidify and form the experimental soil 400. When pouring to the tunnel excavation position, the tunnel shield excavation simulation experimental device 100, externally fitted with a tubular latex membrane, is placed inside the model box 300. Transparent soil material is then poured in layers above the experimental device until the tunnel reaches the corresponding designed burial depth. Then, a vacuum was drawn from the model box 300, allowing the re-poured transparent soil to stand in a vacuum environment until the transparent soil material fully solidified to form the experimental soil body 400. At this time, transparent experimental soil bodies were distributed around the outer periphery of the experimental device. The transparent experimental soil bodies exerted pressure on the outer periphery of each shield tunnel segment assembly 1 under their own weight.

[0046] Layered pouring of the experimental soil (400 mm) ensures that the boundary conditions and initial stress field of the experiment are similar to those of actual tunnel construction scenarios.

[0047] Step 2: Surface settlement is detected by deploying dial gauges on the 300mm surface of the model box. Due to tunnel excavation, soil loss gradually transfers to the ground, manifesting as settlement. Measuring surface settlement is a standard design in tunnel excavation model experiments and is common knowledge to those skilled in the art; therefore, it will not be elaborated upon here.

[0048] The specific method for measuring surface subsidence involves adding particulate tracers to a fluid. These particles can be tiny grains or droplets that move with the fluid's motion. A laser beam illuminates the particles in the fluid, creating a two-dimensional image of the particles on a plane commonly referred to as a laser slice or laser plane. At two consecutive moments, a CCD camera captures images of the particles. These two images, known as image pairs, are typically captured within a very short time interval to capture the instantaneous motion of the particles. The images are then processed using PIV (particle image velocimetry) algorithms to determine the particle displacement between the two moments.

[0049] Step 3: Distributed excavation simulation: Open the control valve 33 and, in conjunction with the flow detection of the flow controller, control the liquid in the deformable cavity 31 to be discharged at the set flow rate; as the liquid is discharged, the cross-sectional area of ​​the deformable cavity 31 gradually decreases from the open end to the closed end (i.e., the shield tunneling direction). Each shield segment assembly 1 installed in the deformable cavity 31 (along the shield tunneling direction) gradually shrinks under the action of the soil and automatically closes magnetically, completing the segment assembly and realizing the support function for the soil.

[0050] Step 4: After the liquid in the deformable cavity 31 is drained, it has no effect on the tunnel lining, which means that the tunnel excavation is complete and the experiment ends.

[0051] In some other embodiments, the experimental soil 400 may also be composed of barite powder, talc powder, gypsum, and water in a specific ratio. During preparation, the soil is first layered within the model box 300 according to a similarity ratio to simulate actual geological strata. This step ensures that the boundary conditions and initial stress field of the experiment are similar to those of actual tunnel construction scenarios. When the tunnel excavation design depth is reached, the tunnel shield excavation simulation experimental device 100, externally fitted with a tubular latex membrane, is placed inside the model box 300, and soil is again layered to ensure that the experimental soil 400 is evenly distributed around the outer periphery of the device. The soil exerts pressure on the outer periphery of each shield segment assembly 1 under its own weight.

[0052] In summary, the tunnel shield excavation simulation experimental device 100 and related experimental methods proposed in this invention, when applied to the scaled-down model experiment of the connecting passage, can effectively simulate the shield construction process. It not only has the advantages of minimal limitations, ease of operation, and low cost, but also provides accurate experimental results. Specific beneficial effects are as follows: (1) In the construction of the shield tunnel connecting passage, due to the limitations of the existing tunnel and model boundary conditions, it is impossible to simulate the shield tunnel construction by pulling the pre-embedded pipe in the traditional model experiment. In addition, the traditional model experiment fixes the segments as a whole, which cannot simulate the segment installation of shield construction. The above-mentioned experimental device and experimental method of this scheme adopts the magnetically assembled shield segment component 1 and the excavation simulation component 3 that can inject and drain fluid. It can realize the simulation of the step-by-step excavation and automatic support process under limited conditions by utilizing the changing trend of cross-sectional area during the drainage process of the pipe cavity. It truly restores the segment unfolding, assembly and force transmission path during shield construction. The simulation effect is realistic and reliable, which increases the reliability of guidance for actual projects.

[0053] (2) After the tunnel segment structure of each shield tunnel segment assembly 1 radially shrinks in volume (i.e., the cross-sectional area decreases due to drainage), it rotates around the pin shaft under the pressure of the outer experimental soil 400 and automatically closes through magnetic attraction, which greatly simplifies the experimental process and significantly improves the automation and repeatability of the experiment.

[0054] (3) The complete set of tunnel shield excavation simulation experimental device 100 has a simple structure, low cost, and can be reused, and has good economic efficiency and practicality.

[0055] Example 2 like Figure 1 As shown, this embodiment proposes a tunnel shield excavation simulation experiment system 200, which includes experimental soil 400, a model box 300, and the tunnel shield excavation simulation experiment device 100 of Embodiment 1. The experimental soil 400 is filled in the model box 300, and the specific filling preparation method is described in Embodiment 1; the tunnel shield excavation simulation experiment device 100 is set in the experimental soil 400 so as to apply confining pressure to the outer periphery of the tunnel shield excavation simulation experiment device 100 through the experimental soil 400.

[0056] The experimental method of the tunnel shield excavation simulation experimental system 200 described above refers to the usage method and experimental principle of the tunnel shield excavation simulation experimental device 100 in Example 1, and will not be repeated here.

[0057] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0058] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A tunnel shield excavation simulation experimental device, characterized in that, This includes tunnel segment assemblies, connection assemblies, and excavation simulation components, among which: The excavation simulation component includes a deformable cavity for injecting and draining fluid and a fluid injection and draining control assembly. One end of the deformable cavity is closed and the other end is provided with an opening. The fluid injection and draining control assembly is connected to the opening and is used to inject and drain fluid into the deformable cavity. The shield tunnel segment assembly includes multiple arc-shaped shield tunnel segments arranged in a ring, and each arc-shaped shield tunnel segment is used to be sleeved on the outside of the deformable cavity along the axial direction of the deformable cavity. The connecting component includes a magnetic suction component one and a magnetic suction component two that can magnetically attract the magnetic suction component one. The magnetic suction component one and the magnetic suction component two are respectively disposed at the two adjacent ends of two curved shield tunnel segments. Any two adjacent curved shield tunnel segments can be automatically magnetically assembled by the connecting component during the drainage process of the deformable cavity.

2. The tunnel shield excavation simulation experimental device according to claim 1, characterized in that, The fluid injection and discharge control assembly includes an injection and discharge pipeline and a control valve disposed on the injection and discharge pipeline, wherein the injection and discharge pipeline is sealed to the opening of the deformable cavity.

3. The tunnel shield excavation simulation experimental device according to claim 2, characterized in that, The fluid injection and discharge control assembly also includes a flow controller disposed on the injection and discharge pipeline.

4. The tunnel shield excavation simulation experimental device according to any one of claims 1 to 3, characterized in that, The deformable lumen expands into a cylindrical shape; the material of the deformable lumen is rubber, silicone, or latex.

5. The tunnel shield excavation simulation experimental device according to any one of claims 1 to 3, characterized in that, The shield tunnel segment assembly includes two arc-shaped shield tunnel segments, namely a first arc-shaped shield tunnel segment and a second arc-shaped shield tunnel segment, both of which are semi-circular segments.

6. The tunnel shield excavation simulation experimental device according to claim 5, characterized in that, The first arc-shaped shield tunnel segment is formed by two quarter-arc segments hinged together by a hinge joint; one of the magnetic attraction element one and the magnetic attraction element two is respectively provided at the two far apart ends of the two quarter-arc segments.

7. The tunnel shield excavation simulation experimental device according to any one of claims 1 to 3, characterized in that, The first magnetic attractor and the second magnetic attractor are respectively an N-pole magnet and an S-pole magnet.

8. A tunnel shield excavation simulation experimental system, characterized in that, The device includes experimental soil, a model box, and a tunnel shield excavation simulation experimental device as described in any one of claims 1 to 7; the experimental soil is filled in the model box, and the tunnel shield excavation simulation experimental device is disposed in the experimental soil so as to apply confining pressure to the outer periphery of the tunnel shield excavation simulation experimental device through the experimental soil.

9. The tunnel shield excavation simulation experimental system according to claim 8, characterized in that, The experimental soil is a transparent experimental soil prepared from n-dodecane, white oil and fumed silica; or, the experimental soil is a soil prepared from barite powder, talc powder, gypsum and water in a specific ratio. The experimental soil was formed by layering soil materials in the model box.

10. A method for simulating tunnel shield excavation, implemented using the tunnel shield excavation simulation system described in claim 8 or 9, characterized in that, include: Multiple shield tunnel segment assemblies are arranged along the axial direction of the deformable cavity to the outside of the deformable cavity that has been filled with fluid, thus completing the assembly of the tunnel shield excavation simulation experimental device; The experimental soil is poured into the model box, and the tunnel shield excavation simulation experimental device is placed in the pouring process; after the experimental soil is poured, the experimental soil is distributed around the outer periphery of the tunnel shield excavation simulation experimental device so as to apply pressure to the outer periphery of each shield segment assembly using the experimental soil. The fluid injection and discharge control component controls the fluid in the deformable cavity to be discharged at a set flow rate until each shield tunnel segment assembly gradually contracts under the action of the experimental soil along the shield tunneling direction and automatically closes magnetically, completing the segment assembly and simulating the soil distribution excavation and automatic support process.

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