Variable gradient shield tunneling simulation test device and method

Abstract

The application discloses a variable-gradient shield tunneling simulation test device and method, which sets a simulation tunnel as a plurality of pipe segment rings arranged in front and back intervals and an elastic sealing ring connected with adjacent two pipe segment rings and sealing the intervals, so that the adjacent two pipe segment rings can relatively vertically swing, and the simulation tunnel is provided with an angle adjusting mechanism for adjusting a vertical included angle between the adjacent two pipe segment rings, so that the simulation tunnel can adjust the vertical included angle between the adjacent two pipe segment rings through the angle adjusting mechanism according to test requirements, so as to present a gradient distribution state required by the test. In addition, the simulation shield shell is made of an elastic material, so that the simulation shield shell has an elastic deformation capacity, can form a corresponding gradient distribution of the simulation tunnel, and can move along the simulation tunnel under the traction of an external traction system in the test process, so as to simulate the tunneling and excavation of a shield tunneling machine, and further more comprehensively and accurately assist in determining various construction parameters in actual engineering.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling test technology, and in particular to a variable slope shield tunneling simulation test device and method. Background Technology

[0002] During the construction of shield tunnels, engineering geological disasters such as soil settlement and ground subsidence are often caused. In order to reduce the impact of such disasters in actual projects, it is often necessary to conduct model tests before construction to simulate the impact of shield construction on the surrounding soil under different working conditions, so as to help determine various construction parameters in actual projects.

[0003] Shield tunnel excavation model tests are generally experimental methods that proportionally convert actual on-site working conditions through geometric, physical, and material similarity comparisons. Shield tunnel model test methods are used to study the effects of different burial depths, dimensions, and segment types on soil settlement, surface subsidence, tunnel uplift, and surrounding buildings caused by tunnel excavation, unloading, and grouting.

[0004] While existing shield tunneling tests can meet the testing requirements under certain working conditions, they still have shortcomings. For example, existing shield tunneling tests are mainly conducted on shield tunnels with no slope or a certain slope value. However, in actual engineering, a tunnel may experience constantly changing slopes in one or more areas. These different slope changes can cause varying degrees of soil settlement and surface subsidence. The existing shield tunneling test models are all rigid straight pipe structures for both the tunnel model and the shield shell model, which can only simulate shield tunneling tests with no slope or a constant slope value, but cannot simulate shield tunneling tests with constantly changing slopes. Summary of the Invention

[0005] The main objective of this invention is to propose a variable slope shield tunnel excavation simulation test device and method, which aims to simultaneously meet the test requirements of the same and different slopes.

[0006] To achieve the above objectives, this invention proposes a variable-slope shield tunneling simulation test device, comprising:

[0007] The model box has an internal space for holding test soil. One side wall of the model box is designed to be movable vertically or partially relative to the test space and has perforations.

[0008] The simulated tunnel is connected at one end to the model box and extends out of the test space through a hole at the other end. The simulated tunnel includes multiple segments of pipe rings arranged at intervals and an elastic sealing ring that connects two adjacent segments of pipe rings and closes the interval.

[0009] An angle adjustment mechanism, located inside the simulated tunnel, is used to adjust the vertical angle between two adjacent tunnel segment rings.

[0010] A simulated shield shell, made of elastic material, is fitted onto a simulated tunnel, with one end extending through a hole into the test space and movable along the simulated tunnel; and

[0011] The monitoring system is used to collect data on the soil before and after deformation.

[0012] This invention also proposes a method for simulating shield tunnel excavation, comprising the following steps:

[0013] S1. Adjust the vertical angle between adjacent segment rings according to the test conditions and requirements, and fit the simulated shield shell onto the simulated tunnel.

[0014] S2. The simulated shield and simulated tunnel are buried in the test soil and a monitoring system is set up. One end of the simulated tunnel is connected to the test space, and the other end of the simulated tunnel and one end of the simulated shield extend out of the test space through a hole.

[0015] S3. Outside the test space, the simulated shield is driven by a traction system to move outward along the simulated tunnel at a set reasonable speed;

[0016] S4. Collect data on the soil before and after deformation through a monitoring system to analyze the deformation of the soil.

[0017] This invention relates to a variable-slope shield tunneling simulation test device and method. The simulated tunnel comprises multiple segment rings spaced at intervals and an elastic sealing ring connecting adjacent segment rings and closing the intervals. This allows adjacent segment rings to swing vertically relative to each other. An angle adjustment mechanism is provided within the simulated tunnel to adjust the vertical angle between adjacent segment rings, enabling the simulated tunnel to exhibit the required slope distribution according to test requirements. Furthermore, the simulated shield shell is made of an elastic material, giving it elastic deformation capabilities to form a slope distribution corresponding to the simulated tunnel. During the test, it can slide down under the traction of an external traction system, simulating the tunneling and excavation of the shield machine. This creates a tail gap in the test soil behind the simulated shield shell's movement direction. Finally, a monitoring system collects data on the soil deformation before and after deformation for analysis, thus providing a more comprehensive and accurate basis for determining various construction parameters in actual engineering projects. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of the connection between two adjacent segments of the present invention.

[0019] Figure 2 This is a partial cross-sectional view of the adjacent segments after being connected in a ring according to the present invention;

[0020] Figure 3 This is a schematic diagram of the experimental process of the present invention;

[0021] Figure 4 This is a three-dimensional schematic diagram of the model box of the present invention;

[0022] Figure 5 This is a schematic diagram illustrating the interaction of the simulated tunnel, inner adhesive layer, grouting pipe, and simulated shield shell of the present invention.

[0023] Figure 6 This is a schematic diagram showing the interaction between the angle sensor, the sensing magnet, and the pivot shaft.

[0024] Figure 7 This is a schematic diagram of an inductive magnet. Detailed Implementation

[0025] The technical solutions in 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 a part of the embodiments of the present invention, and not all of them. 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.

[0026] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0027] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0028] This invention proposes a shield tunnel excavation simulation test device with variable slope.

[0029] In embodiments of the present invention, such as Figure 1-7 As shown, the variable-slope shield tunneling simulation test device includes a model box 1, a simulated tunnel 2, an angle adjustment mechanism, a simulated shield shell 3, and a monitoring system (not shown). The model box 1 internally defines a test space 1a for holding test soil. One side wall of the model box 1 is configured to move vertically or partially relative to the test space 1a and has a through hole 10. The simulated tunnel 2 can be embedded in the test soil within the test space 1a. One end of the simulated tunnel 2 is connected to the model box 1, and the other end extends out of the test space 1a through the hole 10. The simulated tunnel 2 includes multiple segment rings 21 spaced at intervals, and an elastic sealing ring 22 connecting adjacent segment rings 21 and sealing the interval. When the vertical angle (or the angle in the vertical plane) between adjacent segment rings 21 changes, the elastic sealing ring 22 undergoes elastic deformation, maintaining the seal between adjacent segment rings 21 and preventing water, test soil, etc., from entering the simulated tunnel 2. The angle adjustment mechanism is located inside the simulated tunnel 2 and is used to adjust the vertical angle between two adjacent tunnel segment rings 21 to simulate the slope required for the test, either as a whole or in a part of the tunnel 2. The simulated shield shell 3 is made of elastic material, giving it good elastic deformation capability. The simulated shield shell 3 is fitted onto the simulated tunnel 2, forming a slope distribution that is basically the same as the area of ​​the simulated tunnel 2 it fits. One end of the simulated shield shell 3 extends out of the test space 1a through the hole 10 and can move along the simulated tunnel 2, thereby simulating the tunneling and excavation of the tunnel boring machine and creating a tail gap behind the test soil in the direction of movement of the simulated shield shell 3. The monitoring system is used to collect data on the test soil before and after deformation to analyze the deformation of the test soil, thereby more comprehensively and accurately assisting in determining various construction parameters in actual engineering.

[0030] Understandably, during the test, the simulated shield 3 is moved by an external traction system (not shown). The traction system is connected to one end of the simulated shield 3 located outside the test space 1a, and can drive the simulated shield 3 to move relative to the simulated tunnel 2. The traction mechanism is prior art and well known to those skilled in the art; its specific structure and working principle will not be described in detail here.

[0031] As is well known, tunnel gradient refers to the steepness or gentleness of a tunnel. It is usually defined as the ratio of the vertical distance H from one point in the tunnel to the horizontal distance L, denoted by the letter i, which is the tangent of the slope angle. For example, a 3% gradient means that for every 100 meters of distance, the vertical elevation increases (decreases) by 3 meters; a 1% gradient means that for every 100 meters of distance, the vertical elevation increases (decreases) by 1 meter.

[0032] Understandably, in this invention, the vertical angle between any two adjacent segment rings 21 depends on the experimental requirements. When the vertical angle between two adjacent segment rings 21 is 180 degrees, their relative slope is 0; when the vertical angle between two adjacent segment rings 21 is 179 degrees, their relative slope is 1 degree; when all segments are horizontally arranged, the slope of the entire simulated tunnel 2 is zero (i.e., the entire simulated tunnel 2 has no slope); when the angle between all segment rings 21 is 180 degrees and they are all inclined, the entire simulated tunnel 2 has the same slope. In other words, the simulated tunnel 2 can be adjusted as needed to have no slope, have the same slope, or have multiple different slopes within a single simulated tunnel 2, to suit experimental requirements under different working conditions.

[0033] Furthermore, such as Figure 5 As shown, the variable slope shield tunneling simulation test device of the present invention also includes a grouting pipe 4. One end of the grouting pipe 4 is located outside the test space 1a, and the other end extends along the simulated shield shell 3 to the rear end of the simulated shield shell 3 (here, the traction direction of the traction system is considered forward, and vice versa), and can move synchronously with the simulated shield shell 3. The end of the grouting pipe 4 located outside the test space 1a is connected to an external grouting system (not shown). When the simulated shield shell 3 moves along the simulated tunnel 2, the grouting system injects grout into the shield tail gap through the grouting pipe 4 to simulate the backwall grouting in actual shield tunneling, thereby filling the shield tail gap and improving phenomena such as soil settlement and surface subsidence, thus improving the test accuracy. Specifically, the grout can be the same grout material used in actual shield tail grouting, mainly consisting of cement and one or more of fly ash, bentonite, sand, water, and water-reducing agents, and is proportioned according to a similar ratio. The specific proportions are not described here.

[0034] In embodiments of the present invention, such as Figure 5 As shown, a soft inner adhesive layer 31 is fixed to the inner circumference of the simulated shield shell 3 (e.g., by adhesive bonding). The grouting pipe 4 is sandwiched between the inner adhesive layer 31 and the simulated shield shell 3. The inner adhesive layer 31 elastically resists the simulated tunnel 2 to ensure that the simulated shield shell 3 and the grouting pipe 4 can advance more smoothly along the simulated tunnel 2.

[0035] Understandably, the segment ring 21 is essentially a thin-walled cylinder, with its rear end closed and connected to the test space 1a, specifically hinged to the model box 1 and the sidewall opposite to the sidewall with the through hole 10. The material and wall thickness of the segment ring 21 can be selected according to the test requirements, such as using a material with good rigidity, for example, steel, polymer materials, or carbon fiber.

[0036] Understandably, the grouting system is existing technology and well known to those skilled in the art, including components such as grout storage tanks, grouting pumps, flow meters, and pressure gauges. Specific connection methods and working principles will not be elaborated here.

[0037] Furthermore, a layer of grease (not shown) is applied to the mating surfaces of the simulated shield shell 3 and the simulated tunnel 2 pipe, or to the mating surfaces of the inner rubber layer 31 and the simulated tunnel 2, to lubricate the mating surfaces and seal them, thus preventing slurry backflow.

[0038] In one embodiment of the present invention, such as Figure 1 , 2 As shown, adjacent segment rings 21 are hinged together by a hinge structure, and their vertical angle can be adjusted by an angle adjustment mechanism. Specifically, the hinge structure includes a hinge seat 211 fixed inside one end of one of the adjacent segment rings 21, a radial pivot shaft 213 pivotally mounted on the hinge seat 211, and a swing arm 212 fixed inside the adjacent end of the other of the adjacent segment rings 21. The swing arm 212 is fixedly connected to the pivot shaft 213. When the pivot shaft 213 rotates relative to the hinge seat 211, the vertical angle between the adjacent segment rings 21 changes accordingly.

[0039] In the above embodiments, preferably, as follows: Figure 1 , 2 As shown, the angle adjustment mechanism includes a motor 5 fixed on the hinge seat 211, a driving gear 52 mounted on the motor shaft, and a driven gear 214 fixed to one end of the pivot shaft 213. The driving gear 52 and the driven gear 214 mesh. When the motor 5 rotates, the meshing of the driving gear 52 and the driven gear 214 drives the pivot shaft 213 to rotate relative to the hinge seat 211, thereby adjusting the vertical angle between two adjacent segment rings 21. It should be noted that when the motor 5 is not powered or does not receive a working command, the motor 5 is in a self-locking state, and its motor shaft 51 is locked and will not rotate passively, thereby locking the two adjacent segment rings 21 at the required vertical angle. This method of automatically adjusting the vertical angle between two adjacent segment rings 21 by the motor 5 can improve the test efficiency, but the cost is relatively high. Specifically, the hinge seat 211 is located at the radial center of the segment ring 21 and is fixed to the segment ring 21 by multiple first support members 215. The swing arm 212 is located at the radial center of the segment ring 21 and is fixedly connected to the segment ring 21 by multiple second support members 216.

[0040] Furthermore, such as Figure 6 , 7As shown, the present invention also includes an angle measuring instrument 6, which is electrically connected to the control system (not shown) of the motor 5. A slot (not shown) is provided in the middle of the end face of the pivot shaft 213. The angle measuring instrument 6 includes an induction magnet 62 embedded in the slot and an angle sensor 61 mounted on the hinge seat 211. Specifically, it can be mounted on the hinge seat through a bracket (not shown). The sensing end 611 of the angle sensor 61 is directly opposite to the induction magnet 62 and can form magnetic induction. When the induction magnet 62 rotates with the pivot shaft 213, the angle sensor 61 detects the rotation angle of the induction magnet 62 through its sensing end 611 to obtain the change value of the vertical angle between two adjacent tube rings 21. The control system controls whether the motor 5 works based on the angle signal fed back by the angle sensor 61, thereby accurately and quickly adjusting the vertical angle between two adjacent tube rings 21, thereby improving the test efficiency. Understandably, the angle sensor 61 is a magnetic encoder, and the sensing magnet 62 is a circular structure. The side of the sensing magnet 62 facing the sensing part of the angle sensor 61 has N poles and S poles, and the N poles and S poles each occupy half. The angle sensor 61 is existing technology, and its specific details and working principle will not be described in detail here.

[0041] In another embodiment of the present invention, the angle adjustment mechanism includes a bolt (not shown), a nut (not shown) that mates with the bolt, a U-shaped seat (not shown) fixed inside one end of one of the two adjacent segment rings 21, and a swing arm (not shown) fixed inside the adjacent end of the other of the two adjacent segment rings 21. The swing arm extends into and is fitted into the U-shaped seat. The overlapping areas of the U-shaped seat and the swing seat are respectively formed with corresponding first radial holes (not shown) and second radial holes (not shown). The axes of the first radial holes and the second radial holes intersect or substantially intersect with the axes of the corresponding segment rings 21. The shank of the bolt passes through the first radial holes and the second radial holes and is screwed into the nut. When the nut is loosened, the vertical angle between the two adjacent segment rings 21 can be adjusted. When the nut is tightened, the U-shaped seat can be elastically deformed and the swing arm can be clamped to prevent relative swinging, thereby locking the two adjacent segments in the desired vertical angle state. The vertical angle between the two adjacent segment rings 21 can be determined manually by measuring with a protractor or by measuring with an automatic protractor. Similarly, the U-shaped seat is located at the radial center of the segment ring 21 and is fixedly connected to the segment ring 21 by multiple first support members (not shown). The swing arm is located at the radial center of the segment ring 21 and is fixedly connected to the segment ring 21 by multiple second support members (not shown).

[0042] In this embodiment of the invention, the connection between the elastic sealing ring 22 and the two adjacent segment rings 21 can be implemented in various ways. For example, the elastic sealing ring 22 can be fixed to the two adjacent segment rings 21 by means of bonding, ultrasonic welding, or injection molding. Alternatively, it can be connected by a screw structure, a snap-fit ​​structure, or other feasible connection structure. The above connection methods are all common connection methods in the art and will not be described in detail here.

[0043] The elastic sealing ring 22 can be made of one or more of rubber, plastic or silicone. In order to balance the strength and elastic deformation of the elastic sealing ring 22, the elastic sealing ring 22 is covered with copper fiber or metal sheet.

[0044] In embodiments of the present invention, such as Figure 4 As shown, the model box 1 is a square container with an open top. It includes a main body surrounded by three fixed side plates 12, 13, and 14 and a bottom plate 11, and a movable side plate 15 (the movable side plate 15 is the side wall that can be moved up and down relative to the test space 1a, either as a whole or partially). One side of the main body is open, and the movable side plate 15 can be vertically and movably installed on the open side of the main body, and it is sealed with the main body at the joint (for example, a sealing strip is provided at the joint) to prevent soil and water leakage. A locking device is also provided to lock the movable side plate 15 at the desired height, and the locking device can be released when the height of the movable side plate 15 needs to be adjusted.

[0045] Optionally, the locking device can be a screw, a snap-fit ​​structure, or a clamp structure. Alternatively, the locking device can be a cylinder, a hydraulic cylinder, or a linear motor. The telescopic rod of the cylinder, hydraulic cylinder, or linear motor is connected to the movable side plate 15. When the telescopic rod extends or retracts, it drives the movable side plate 15 to move up and down relative to the test space 1a. When the telescopic rod stops moving, the movable side plate 15 is locked. Controlled by a cylinder, hydraulic cylinder, or linear motor 5, high precision and efficiency are achieved.

[0046] In the above embodiments, such as Figure 3 , 4As shown, the base plate 11 has a guide hole 111 through which the lower end of the movable side plate 15 passes. Two fixed side plates 13 and 14 adjacent to the movable side plate 15 have relatively extending extensions 131 and 141. The movable side plate 15 is sealed to the extensions and can move up and down along the extensions 131 and 141. The movable side plate 15 is also sealed to the guide hole 111 and can move up and down relative to the guide hole 111. Preferably, sealing strips can be provided in the guide hole 111 and the extensions 131 and 141, respectively. The sealing strips elastically seal against the guide hole 111 and the movable side plate 15, and the extensions 131 and 141 and the movable side plate 15, respectively. The through hole 10 is formed in the movable side plate 15. A sealing outer ring 7 is installed at the through hole 10 to seal against the simulated shield 3. The simulated shield 3 passes through the sealing outer ring 7 and can move relative to the sealing outer ring 7 while maintaining a sealed fit, preventing leakage of the test soil and water. Meanwhile, the sealing outer ring 7 can prevent the simulated shield shell 3 from directly contacting the rigid movable side plate 15, reducing the resistance experienced by the simulated shield shell 3 during its movement.

[0047] It is understood that the monitoring system described in this invention is prior art, generally including a data acquisition device (not shown), and at least one monitoring instrument such as a miniature earth pressure cell, resistance strain gauge, miniature inclinometer, dial gauge, etc., which is communicatively connected to the data acquisition device. The specific structure, setup, and working principle of the aforementioned data acquisition device and testing instrument are well known to those skilled in the art and are not improvements of this invention; therefore, they will not be elaborated upon here.

[0048] In this embodiment of the invention, the material of the simulated shield 3 can be implemented in various ways, based on the requirement that it can move along the simulated tunnel 2 with different slopes. For example, it can be tripropylene polypropylene (PPR) or polyethylene plastic (PE).

[0049] Understandably, the end of the simulated tunnel 2 connected to the test space 1a should be sealed to prevent water and test soil from entering the interior of the simulated tunnel 2.

[0050] After introducing the implementation method of the variable slope shield tunneling simulation test device of the present invention, the implementation method of the simulation test method using the above-mentioned variable slope shield tunneling simulation test device will be described next. The specific structure of the variable slope shield tunneling simulation test device is as described in the above embodiments, and repeated parts will not be described again.

[0051] In embodiments of the present invention, such as Figure 1-7 As shown, the shield tunneling simulation test method includes the following steps:

[0052] S1. Adjust the vertical angle between adjacent segment rings 21 according to the test conditions and requirements so that the simulated tunnel 2 presents the slope distribution state required for the test, and then put the simulated shield 3 on the simulated tunnel 2.

[0053] Optionally, in step S1, the vertical angle between any two adjacent segment rings 21 can be adjusted first, and then the simulated shield 3 can be fitted onto the simulated tunnel 2. Alternatively, the simulated shield 3 can be fitted onto the simulated tunnel 2 first, and then the vertical angle between any two adjacent segment rings 21 can be adjusted.

[0054] In this embodiment of the invention, the vertical angle between two adjacent segment rings 21 can be adjusted manually or automatically by controlling the motor 5. In some embodiments, the hinge structure includes a hinge seat 211 fixed inside one end of one of the adjacent segment rings 21 and a radial pivot shaft 213 pivotally mounted on the hinge seat 211, and a swing arm 212 fixed inside the adjacent end of the other of the adjacent segment rings 21. The swing arm 212 is fixedly connected to the pivot shaft 213. When the pivot shaft 213 rotates relative to the hinge seat 211, the vertical angle between the two adjacent segment rings 21 changes accordingly. In this embodiment, preferably, the angle adjustment mechanism includes a motor 5 fixed on the hinge seat 211, a drive gear 52 disposed on the motor shaft 51, and a driven gear 214 fixed at one end of the pivot shaft 213. The drive gear 52 and the driven gear 214 mesh. In this embodiment, the process of adjusting the vertical angle between two adjacent segment rings 21 includes sending a working command to the motor 5 through the control system according to the test conditions and requirements. This causes the motor shaft 51 to drive the drive gear 52 to rotate by a predetermined angle. The drive gear 52 then drives the driven gear 214 to rotate the pivot shaft 213. The meshing of the drive gear 52 and the driven gear 214 drives the pivot shaft 213 to rotate relative to the hinge seat 211, thereby causing the swing arm 212 to adjust the vertical angle between two adjacent segment rings 21. It should be noted that when the motor 5 is not powered or does not receive a working command, the motor 5 is in a self-locking state, and its motor shaft 51 is locked and will not rotate passively. This locks the two adjacent segment rings 21 at the required vertical angle. This method of automatically adjusting the vertical angle between two adjacent segment rings 21 by the motor 5 can improve test efficiency, but the cost is relatively high. Specifically, the hinge seat 211 is located at the radial center of the segment ring 21 and is fixedly connected to the segment ring 21 via multiple first support members 215. The swing arm 212 is located at the radial center of the segment ring 21 and is fixedly connected to the segment ring 21 via multiple second support members 216.

[0055] Furthermore, such as Figure 6 , 7As shown, the present invention also includes an angle measuring instrument 6, which is electrically connected to the control system (not shown) of the motor 5. A slot (not shown) is provided in the middle of the end face of the pivot shaft 213. The angle measuring instrument 6 includes an induction magnet 62 embedded in the slot and an angle sensor 61 mounted on the hinge seat 211. The sensing end 611 of the angle sensor 61 is directly opposite to the induction magnet 62 and can form magnetic induction. When the induction magnet 62 rotates with the pivot shaft 213, the angle sensor 61 obtains the change value of the vertical angle between two adjacent tube rings 21 by detecting the rotation angle of the induction magnet 62 through its sensing end 611. The control system controls whether the motor 5 works based on the angle signal fed back by the angle sensor 61, thereby accurately and quickly adjusting the vertical angle between two adjacent tube rings 21, thereby improving the test efficiency. Understandably, the angle sensor 61 is a magnetic encoder, and the sensing magnet 62 is a circular structure. The side of the sensing magnet 62 facing the sensing part of the angle sensor 61 has N poles and S poles, and the N poles and S poles each occupy half. The angle sensor 61 is existing technology, and its specific details and working principle will not be described in detail here.

[0056] In the above embodiment, step S1, which adjusts the vertical angle between two adjacent segment rings 21, includes the following process:

[0057] S11. According to the experimental requirements, a predetermined vertical angle value is set between two adjacent segment rings 21 in the control system. As for how to set it, those skilled in the art can know how to set it according to the description in this specification and the technical problem to be solved, and it will not be described in detail here.

[0058] S12. The control system sends a working command to the motor 5, causing the motor shaft 51 to rotate and the pivot shaft 213 to rotate through the meshing of the drive gear 52 and the driven gear 214, thereby causing the hinge 211 and the swing arm 212 of the two adjacent tube rings 21 to swing relative to each other.

[0059] S13. When the angle measuring instrument 6 detects that the rotation angle of the pivot shaft 213 has reached the predetermined value, the control system controls the motor 5 to stop rotating. This completes the adjustment of the vertical angle between adjacent segment rings 21.

[0060] Understandably, in this embodiment of the invention, the vertical angle between any two adjacent segment rings 21 depends on the test requirements. When the vertical angle between two adjacent segment rings 21 is 180 degrees, their relative slope is 0; when the vertical angle between two adjacent segment rings 21 is 179 degrees, their relative slope is 1 degree; when all segments are horizontally arranged, the slope of the entire simulated tunnel 2 is zero (i.e., the entire simulated tunnel 2 has no slope); when the angle between all segment rings 21 is 180 degrees and they are all inclined, the entire simulated tunnel 2 has the same slope. In other words, the simulated tunnel 2 can be adjusted as needed to have no slope, have the same slope, or have multiple different slopes within a single simulated tunnel 2, which can be adapted to test requirements under different working conditions.

[0061] S2. The simulated shield 3 and the simulated tunnel 2 are buried in the test soil and a monitoring system is set up. One end of the simulated tunnel 2 is connected to the test space 1a, and the other end of the simulated tunnel 2 and one end of the simulated shield 3 extend out of the test space 1a through the hole 10.

[0062] Understandably, the monitoring system is mainly used to collect data on the test soil before and after deformation, in order to analyze the deformation of the test soil and thus more comprehensively and accurately assist in determining various construction parameters in actual engineering projects. The monitoring system is existing technology and generally includes a data acquisition device (not shown), and at least one monitoring instrument such as a miniature earth pressure cell, resistance strain gauge, miniature inclinometer, or dial gauge that is connected to the data acquisition device. The specific structure, setup, and working principles of the aforementioned data acquisition device and testing instruments are well known to those skilled in the art and will not be elaborated upon here.

[0063] In this embodiment of the invention, the process of burying and compacting the simulated shield 3 and simulated tunnel 2 in the test soil preferably involves pre-adding and compacting a predetermined thickness of test soil, then placing the simulated shield 3 and simulated tunnel 2 on the predetermined thickness of test soil; then continuing to add and compact test soil in layers until the simulated shield 3 and simulated tunnel 2 are completely buried. The preparation of the test soil is prior art and will not be described in detail here.

[0064] S3. Outside the test space 1a, the simulated shield shell 3 is driven by the traction system to move outward along the simulated tunnel 2 at a set reasonable speed to simulate the tunneling and excavation of the tunnel boring machine, so that the test soil forms a tail gap behind the simulated shield shell 3 in the direction of movement.

[0065] Understandably, during the experiment, the simulated shield 3 is moved by an external traction system. The traction system is connected to one end of the simulated shield 3 located outside the test space 1a, and can drive the simulated shield 3 to move relative to the simulated tunnel 2. The traction system is located outside the model box 1 and includes a drive mechanism and a connecting frame, etc. One end of the connecting frame is detachably connected to the simulated shield 3, specifically through a clamp, and the other end is connected to the drive mechanism. The drive mechanism can drive the simulated shield 3 to move along the simulated tunnel 2 at a set speed according to a set command, so as to simulate the tunneling and excavation of the tunnel boring machine. The drive mechanism can be a pneumatic cylinder, hydraulic cylinder, or electric cylinder, etc.

[0066] Furthermore, in step S3, which involves driving the simulated shield 3 to move outward along the simulated tunnel 2 at a set reasonable speed via a traction system, the process of grouting the tail gap through the grouting pipe 4 is also included.

[0067] Specifically, one end of the grouting pipe 4 is located outside the test space 1a, and the other end extends along the simulated shield shell 3 to the rear end of the simulated shield shell 3 (here, the traction direction of the traction system is considered forward, and vice versa), and can move synchronously with the simulated shield shell 3. The end of the grouting pipe 4 located outside the test space 1a is connected to the grouting system. As the simulated shield shell 3 moves along the simulated tunnel 2, the grouting system injects grout into the shield tail gap through the grouting pipe 4 to simulate the backwall grouting in actual shield tunneling construction, thereby filling the shield tail gap and improving phenomena such as soil settlement and surface subsidence, thus improving the test accuracy. Specifically, the grout can be the same grout material used in actual shield tail grouting, mainly consisting of cement and one or more of fly ash, bentonite, sand, water, and water-reducing agents, mixed in a similar proportion. The specific proportions are not elaborated here.

[0068] In this embodiment of the invention, a soft (e.g., by adhesive bonding or by means of) inner adhesive layer 31 is fixed to the inner circumference of the simulated shield shell 3. The grouting pipe 4 is sandwiched between the inner adhesive layer 31 and the simulated shield shell 3. The inner adhesive layer 31 elastically resists the simulated tunnel 2 to ensure that the simulated shield shell 3 and the grouting pipe 4 can advance more smoothly along the simulated tunnel 2.

[0069] Understandably, the grouting system is existing technology and well known to those skilled in the art, including components such as grout storage tanks, grouting pumps, flow meters, and pressure gauges. Specific connection methods and working principles will not be elaborated here.

[0070] Furthermore, a layer of grease (not shown) is applied to the mating surfaces of the simulated shield shell 3 and the simulated tunnel 2 pipe, or to the mating surfaces of the inner rubber layer 31 and the simulated tunnel 2, to lubricate the mating surfaces and seal them, thus preventing slurry backflow.

[0071] S4. Data on the soil deformation before and after testing is collected through a monitoring system to analyze the deformation of the soil. This, in turn, can more comprehensively and accurately assist in determining various construction parameters in actual engineering projects.

[0072] It should be noted that existing technologies can be used to collect data on the soil before and after deformation, as well as to analyze the deformation of the soil. These details will not be elaborated here.

[0073] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A shield tunneling simulation test device with variable slope, characterized in that, include: The model box has an internal space for holding test soil. One side wall of the model box is designed to be movable vertically or partially relative to the test space and has perforations. The simulated tunnel is connected at one end to the model box and extends out of the test space through a hole at the other end. The simulated tunnel includes multiple segments of pipe rings arranged at intervals and an elastic sealing ring that connects two adjacent segments of pipe rings and closes the interval. An angle adjustment mechanism, located inside the simulated tunnel, is used to adjust the vertical angle between two adjacent tunnel segment rings. A simulated shield shell, made of elastic material, is fitted onto a simulated tunnel, with one end extending out of the test space through a hole and movable along the simulated tunnel; as well as The monitoring system is used to collect data on the soil before and after deformation.

2. The variable slope shield tunneling simulation test device as described in claim 1, characterized in that: It also includes a grouting pipe, one end of which is located outside the test space, and the other end extends along the simulated shield to the rear end of the simulated shield and can move synchronously with the simulated shield. The end of the grouting pipe located outside the test space is connected to an external grouting system.

3. The variable slope shield tunneling simulation test device as described in claim 2, characterized in that: A soft inner rubber layer is fixed to the inner circumference of the simulated shield shell, and the grouting pipe is sandwiched between the inner rubber layer and the simulated shield shell, with the inner rubber layer elastically resisting the simulated tunnel.

4. The variable slope shield tunneling simulation test device as described in claim 1, characterized in that: A hinge seat is fixed inside one end of one of the two adjacent segment rings, and a radial pivot shaft is pivotally mounted on the hinge seat. A swing arm is fixed inside the adjacent end of the other two adjacent segment rings, and the swing arm is fixedly connected to the pivot shaft.

5. The variable slope shield tunneling simulation test device as described in claim 4, characterized in that: The angle adjustment mechanism includes a motor fixed on a hinge seat, a drive gear on the motor shaft, and a driven gear fixed at one end of the pivot shaft, wherein the drive gear and the driven gear mesh.

6. The variable slope shield tunneling simulation test device as described in claim 5, characterized in that: It also includes an angle measuring instrument, which is electrically connected to the control system of the motor. A slot is provided in the middle of the end face of the pivot shaft. The angle measuring instrument includes an induction magnet embedded in the slot and an angle sensor mounted on the hinge seat. The sensing end of the angle sensor is directly opposite the induction magnet and can form magnetic induction.

7. The variable slope shield tunneling simulation test device as described in any one of claims 1 to 6, characterized in that: The test chamber is a square container with an open top, including a main body surrounded by three fixed side plates and a bottom plate, and movable side plates. One side of the main body is open, and the movable side plates can be vertically and movably installed on the open side of the main body and are sealed and fitted with the main body. There is also a locking device for locking the movable side plates at the required height.

8. A test method using the variable slope shield tunneling simulation test device according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Adjust the vertical angle between adjacent segment rings according to the test conditions and requirements, and fit the simulated shield shell onto the simulated tunnel. S2. The simulated shield and simulated tunnel are buried in the test soil and a monitoring system is set up. One end of the simulated tunnel is connected to the test space, and the other end of the simulated tunnel and one end of the simulated shield extend out of the test space through a hole. S3. Outside the test space, the simulated shield is driven by a traction system to move outward along the simulated tunnel at a set reasonable speed; S4. Collect data on the soil before and after deformation through a monitoring system to analyze the deformation of the soil.

9. The test method for using the variable slope shield tunneling simulation test device according to any one of claims 1 to 7 as described in claim 8, characterized in that, Step S1, which involves adjusting the vertical angle between two adjacent segment rings, includes the following process: S11. Set the predetermined vertical angle between two adjacent segment rings in the control system according to the test requirements; S12. The control system sends a working command to the motor, causing the motor shaft to rotate and the pivot shaft to rotate through the meshing of the drive gear and the driven gear, thereby causing the hinge seats and swing arms of the two adjacent tube rings to swing relative to each other. S13. When the angle measuring instrument detects that the rotation angle of the pivot shaft has reached the predetermined value, the control system controls the motor to stop rotating.

10. The test method for using the variable slope shield tunneling simulation test device according to any one of claims 1 to 7 as described in claim 8, characterized in that: Step S3, which involves driving the simulated shield shell to move outward along the simulated tunnel at a set reasonable speed using a traction system, also includes the process of grouting the shield tail gap through a grouting pipe.

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