A tunnel boring test device for simulating small - scale ground loss

Abstract

The present invention discloses a tunnel boring test device for simulating small-scale ground loss, which relates to the technical field of tunnel boring tests. The device includes a tunnel model and a telescoping mechanism. The tunnel model includes rigid arc-shaped plates and soft connectors that can be elastically deformed. Multiple rigid arc-shaped plates and multiple soft connectors are alternately connected to form a circular tube. The telescoping mechanism is used to control the expansion and contraction of the tunnel model. Therefore, the rigid arc-shaped plates provide guarantee for the mechanical strength of the tunnel model, while the soft connectors enable the elastic telescopic regulation of the tunnel model. At this time, even if the telescoping mechanism is used to control the expansion and contraction of the tunnel model, the deformation of the soft connectors has little impact on the overall shape of the tunnel model, ensuring that the tunnel model can always maintain a circular tubular structure, that is, the shape of the tunnel model is consistent with the shape of the tunnel lining, thus effectively solving the problem that the existing tunnel boring test device cannot accurately simulate the actual construction environment.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel boring tests, and particularly relates to a tunnel boring test device for simulating minor ground loss. Background Art

[0002] In recent years, shield tunnels have been widely used in the construction of subway tunnels. When a shield machine is applied, the tunnel lining is initially located inside the shield machine. As the shield machine advances forward, the tunnel lining will gradually emerge from the tail of the shield machine and then be fixed in the excavated soil mass.

[0003] However, when the tunnel lining just emerges from the shield tail, due to the diameter difference between the shield machine shell and the tunnel lining, there will be a certain gap between the tunnel lining and the surrounding soil mass. This gap is called the shield tail gap, and this shield tail gap will lead to ground loss. So-called ground loss refers to the difference between the volume of the soil actually excavated during tunnel construction and the volume of the tunnel after completion. Specifically, the ground loss rate is equal to the volume of the shield tail gap divided by the volume of the soil actually excavated for the tunnel.

[0004] It can be seen that during the tunneling process of shield tunnels, shield tail gaps will inevitably occur. If the shield tail gaps are not controlled, the surrounding soil mass of the tunnel lining will move towards the tunnel lining direction because there is no support. The movement of the soil mass around the tunnel will drive the movement of the surface soil mass, thereby causing the phenomenon of surface soil settlement. Surface buildings and surface roads will be affected, and various engineering geological disasters will be caused.

[0005] Therefore, it is necessary to conduct indoor tests with different ground loss rates as variables to predict the impact of shield construction on the surrounding soil mass under different ground loss rates and to determine how to control the shield tail gap in actual engineering.

[0006] To solve the above problems, the prior art has developed a tunnel boring test device. This tunnel boring test device includes a tunnel model and a scaling mechanism. The scaling mechanism is used to adjust the radial dimension of the tunnel model to simulate ground loss by using the change in the radial dimension of the tunnel model.

[0007] However, this tunnel model is made by integrally forming with iron sheet. So when the scaling mechanism controls the tunnel model to expand, it is actually forcibly stretching the iron sheet, thus unable to ensure that the tunnel model remains circular after expansion, which is different from the situation where the tunnel lining at the construction site is circular, resulting in the inability to achieve accurate experimental simulation at all.

[0008] Therefore, it has become an urgent problem to study a tunnel boring test device that can accurately simulate the actual construction environment. Summary of the Invention

[0009] The object of the present invention is to provide a tunnel boring test device for simulating small - amplitude ground loss, so as to solve the problem that the existing tunnel boring test device cannot accurately simulate the actual construction environment.

[0010] To solve the above - mentioned technical problem, the present invention provides a tunnel boring test device for simulating small - amplitude ground loss, which includes a tunnel model and a scaling mechanism; the tunnel model includes rigid arc - shaped plates and a soft connector with telescopic deformation, and multiple rigid arc - shaped plates and multiple soft connectors are alternately connected into a circular tube shape; the scaling mechanism is used to control the expansion and contraction of the tunnel model, and the scaling mechanism includes a power output unit, a lead screw, a movable nut, a transmission rod, and a support plate; the power output unit is used to drive the lead screw to rotate; the lead screw is arranged coaxially with the axis of the tunnel model; the movable nut is sleeved outside the lead screw, and the movable nut is thread - connected with the lead screw; multiple transmission rods are arranged around the circumferential side of the movable nut, and multiple transmission rods are all movably connected with the movable nut; multiple support plates are respectively fixedly connected to the inner walls of multiple rigid arc - shaped plates, and multiple support plates are respectively movably connected with multiple transmission rods.

[0011] In one embodiment, splicing grooves are provided on both opposite side walls of the rigid arc - shaped plate, and the splicing grooves extend along the axial direction of the rigid arc - shaped plate; the soft connector includes a straight - groove part and a connecting part, the straight - groove part is a linear groove - shaped structure, and connecting parts are provided on both outer side walls of the straight - groove part, and the connecting parts are installed in the splicing grooves.

[0012] In one embodiment, the cross - sections of the splicing groove and the connecting part are both convex - shaped with matching sizes, and the splicing groove and the connecting part assemble the tunnel model into a radially anti - detachment structure; multiple fixing through - holes are provided on the groove wall of the splicing groove, and multiple fixing through - holes all penetrate the inner surface of the rigid arc - shaped plate, and fixing bolts are installed in multiple fixing through - holes, and the fixing bolts are thread - connected with the fixing screw holes of the soft connector.

[0013] In one embodiment, a limiting plate is supported on the lead screw, the limiting plate is arranged inside the tunnel model, and multiple limiting grooves are provided on the limiting plate, and multiple limiting grooves all extend along the radial direction of the tunnel model; mounting plates are connected to multiple support plates, limiting pins are provided on multiple mounting plates, and multiple limiting pins are respectively inserted into multiple limiting grooves, and the cooperation between multiple limiting pins and multiple limiting grooves is used to limit the expansion and contraction range of the tunnel model.

[0014] In one embodiment, the tunnel boring test device further includes a first flexible sealing plate and a second flexible sealing plate that can be telescopically deformed. The first flexible sealing plate and the second flexible sealing plate respectively seal and cover the two tunnel openings of the tunnel model; and a first sealing shaft sleeve is provided on the first flexible sealing plate, and a second sealing shaft sleeve is provided on the second flexible sealing plate. The two ends of the lead screw are respectively inserted into the first sealing shaft sleeve and the second sealing shaft sleeve.

[0015] In one embodiment, first transparent baffles and second transparent baffles are respectively installed at the two ends of the lead screw outside the tunnel model; the first transparent baffle seals and covers the first flexible sealing plate, and a first annular backing plate is hermetically clamped between the periphery of the first transparent baffle and the first flexible sealing plate; the second transparent baffle seals and covers the second flexible sealing plate, and a second annular backing plate is hermetically clamped between the periphery of the second transparent baffle and the second flexible sealing plate.

[0016] In one embodiment, grouting holes are provided on the surface of the hard arc-shaped plate, and the grouting holes penetrate through the hard arc-shaped plate; a plurality of grouting joints are provided on the first flexible sealing plate, and the plurality of grouting joints are respectively connected to the plurality of grouting holes through pipelines.

[0017] In one embodiment, a sensor mounting hole is provided on the outer surface of the hard arc-shaped plate, and a pressure sensor is provided in the sensor mounting hole.

[0018] In one embodiment, the tunnel boring test device further includes a first arc-shaped positioning plate and a second arc-shaped positioning plate; a plurality of the first arc-shaped positioning plates are all attached to the outer surface of the first flexible sealing plate, and the plurality of first arc-shaped positioning plates are respectively arranged in alignment with the plurality of hard arc-shaped plates. The first arc-shaped positioning plate, the first flexible sealing plate and the hard arc-shaped plate are fixedly connected by bolts; a plurality of the second arc-shaped positioning plates are all attached to the outer surface of the second flexible sealing plate, and the plurality of second arc-shaped positioning plates are respectively arranged in alignment with the plurality of hard arc-shaped plates. The second arc-shaped positioning plate, the second flexible sealing plate and the hard arc-shaped plate are fixedly connected by bolts.

[0019] In one embodiment, a first shaft hole is provided at the geometric center of the first flexible sealing plate, and a second shaft hole is provided at the geometric center of the second flexible sealing plate; the first sealing shaft sleeve includes a first inner perforated plate, a first outer perforated plate and a first sealing bearing. In the direction from the inside to the outside of the tunnel model, the first inner perforated plate, the first shaft hole and the first outer perforated plate are arranged in a state where the hole positions are coaxial, and the first inner perforated plate, the first shaft hole and the first outer perforated plate are fixedly connected by bolts; the first sealing bearing is sealingly installed in the hole positions of the first inner perforated plate, the first shaft hole and the first outer perforated plate, and the lead screw is sealingly sleeved inside the first sealing bearing; the second sealing shaft sleeve includes a second inner perforated plate, a second outer perforated plate and a second sealing bearing. In the direction from the inside to the outside of the tunnel model, the second inner perforated plate, the second shaft hole and the second outer perforated plate are arranged in a state where the hole positions are coaxial, and the second inner perforated plate, the second shaft hole and the second outer perforated plate are fixedly connected by bolts; the second sealing bearing is sealingly installed in the hole positions of the second inner perforated plate, the second shaft hole and the second outer perforated plate, and the lead screw is sealingly sleeved inside the second sealing bearing.

[0020] The beneficial effects of the present invention are as follows:

[0021] Since the tunnel model includes rigid arc-shaped plates and soft connectors that can be elastically deformed, multiple rigid arc-shaped plates and multiple soft connectors are alternately connected into a circular tube shape, and the expansion and contraction mechanism is used to control the expansion and contraction of the tunnel model. Therefore, the rigid arc-shaped plates provide guarantee for the mechanical strength of the tunnel model, while the soft connectors enable the elastic expansion and contraction regulation of the tunnel model. At this time, even if the expansion and contraction mechanism is used to control the expansion and contraction of the tunnel model, the deformation amount of the soft connectors has little impact on the overall shape of the tunnel model, ensuring that the tunnel model can always maintain a circular tube structure, that is, the shape of the tunnel model is consistent with the shape of the tunnel lining, thus effectively solving the problem that the existing tunnel boring test device cannot accurately simulate the actual construction environment. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure A-1 It is a schematic diagram of the prior art one;

[0024] Figure A-2 It is a schematic diagram of the prior art two;

[0025] Figure A-3 Schematic diagram three of the prior art;

[0026] Figure 1-1 Schematic diagram of the structure provided by the first embodiment of the present invention;

[0027] Figure 1-2 is Figure 1-1 Rear view structure diagram of;

[0028] Figure 1-3 is Figure 1-1 Tunnel model structure diagram of;

[0029] Figure 1-4 is Figure 1-3 Hard arc plate structure diagram of;

[0030] Figure 1-5 is Figure 1-3 Soft connector structure diagram of;

[0031] Figure 2-1 Tunnel model structure diagram provided by the first embodiment of the present invention;

[0032] Figure 2-2 is Figure 2-1 Hard arc plate structure diagram of;

[0033] Figure 2-3 is Figure 2-1 Soft connector structure diagram of;

[0034] Figure 3-1 Rear view structure diagram provided by the third embodiment of the present invention;

[0035] Figure 4-1 Schematic diagram of the structure provided by the fourth embodiment of the present invention;

[0036] Figure 4-2 is Figure 4-1 Rear view structure diagram of;

[0037] Figure 4-3 is Figure 4-1 First flexible seal plate structure diagram of;

[0038] Figure 4-4 is Figure 4-1 Second flexible seal structure diagram of;

[0039] Figure 4-5 is Figure 4-1 Cross-sectional structure diagram of;

[0040] Figure 4-6 is Figure 4-5 Enlarged structure diagram of part A of;

[0041] Figure 4-7 is Figure 4-5 the enlarged structural schematic diagram of part B;

[0042] Figure 5-1 is the structural schematic diagram provided by the fifth embodiment of the present invention;

[0043] Figure 5-2 is Figure 5-1 the rear view structural schematic diagram;

[0044] Figure 5-3 is Figure 5-1 the front view structural schematic diagram after removing the transparent baffle;

[0045] Figure 5-4 is Figure 5-3 the rear view structural schematic diagram;

[0046] Figure 6-1 is the structural schematic diagram provided by the sixth embodiment of the present invention;

[0047] Figure 6-2 is Figure 6-1 the structural schematic diagram after removing the transparent baffle;

[0048] Figure 6-3 is Figure 6-1 the structural schematic diagram of the rigid arc plate;

[0049] Figure 7-1 is the structural schematic diagram provided by the seventh embodiment of the present invention.

[0050] The reference numerals are as follows:

[0051] A1, liquid sac; A2, tunnel lining; A3, large outer tube; A4, small inner tube; A5, iron sheet tunnel model; A6, expansion and contraction device;

[0052] 10, tunnel model; 11, rigid arc plate; 111, splicing groove; 112, fixed through hole; 113, fixed bolt; 114, grouting hole; 115, sensor installation hole; 116, pressure sensor; 12, soft connector; 121, connecting part; 122, straight groove part; 123, fixed screw hole;

[0053] 20, expansion and contraction mechanism; 211, first support seat; 212, second support seat; 213, first bearing seat; 214, second bearing seat; 215, power output motor; 216, reducer; 217, coupling; 218, fixing plate; 22, lead screw; 23, movable nut; 231, first ear plate; 24, transmission rod; 25, support plate; 251, second ear plate; 252, limit pin; 253, mounting plate; 26, limit plate; 261, limit groove;

[0054] 31. first flexible sealing plate; 311. first axial hole; 312. grouting joint; 32. second flexible sealing plate; 321. second axial hole;

[0055] 41. a first arc-shaped positioning plate; 42. a second arc-shaped positioning plate;

[0056] 51, first sealing sleeve; 511, first inner plate with holes; 512, first outer plate with holes; 513, first sealed bearing; 52, second sealing sleeve; 521, second inner plate with holes; 522, second outer plate with holes; 523, second sealed bearing;

[0057] 61. first transparent baffle; 62. second transparent baffle;

[0058] 71. A first annular gasket; 72. A second annular gasket. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0060] When simulating formation loss, the following simulation methods are commonly used:

[0061] The first simulation method is Figure A-1 As shown, the currently commonly used stratum loss test simulation equipment is implemented in the form of a liquid capsule A1, which is wrapped around the outside of the tunnel lining A2. At the beginning, the liquid capsule A1 is filled with water, which will support the liquid capsule; when it is necessary to simulate the stratum loss caused by the forward excavation of the shield, the water in the liquid capsule A1 is discharged, and the liquid capsule A1 will shrink, thereby indirectly changing the tunnel diameter, thereby realizing the simulation of the diameter difference between the shield tail and the tunnel lining A2.

[0062] However, since the liquid capsule A1 is arranged in blocks with gaps between the blocks, and the liquid capsule A1 is an ellipsoidal object, multiple liquid capsules A1 cannot be connected to form a regular circle, so the outer wall of the simulated tunnel lining A2 will be an irregular circle, which deviates from the actual project.

[0063] The second simulation method is Figure A-2As shown in the figure, there is also a device that uses a large outer tube A3 to enclose a small inner tube A4 to simulate formation loss. The large outer tube A3 is used to simulate the shield machine, and the small inner tube A4 is used to simulate the tunnel lining. At the beginning of the simulation experiment, the large outer tube A3 completely wraps the small inner tube A4, and the small inner tube A4 is fixed in the soil to ensure that the small inner tube A4 does not move during the test. When the simulated shield machine advances forward and causes formation loss, the large outer tube A3 is pulled outwards to expose the small inner tube A4 inside it. This state is like the moment when the tunnel lining exits the shield tail in actual engineering. Therefore, the diameter difference between the large outer tube A3 and the small inner tube A4 at this time is the shield tail gap, thus realizing the simulation of the diameter difference between the shield tail and the tunnel lining.

[0064] However, it is extremely difficult to change the formation loss rate with this device because each time the formation loss rate is changed, different-sized large outer tubes A3 and small inner tubes A4 need to be replaced again, making the use process extremely inconvenient.

[0065] Moreover, for the above two simulation methods, the formation loss rates simulated by the two simulation methods are relatively large. The formation loss rates they simulate are generally 5% - 10%, and it is impossible to achieve the simulation of a small range of formation loss rates. However, in general actual situations, the formation loss rate is between 0.5% - 3%. That is to say, the above two simulation methods are still difficult to accurately simulate the actual situation.

[0066] For example, for the first simulation method, its liquid bag A1 is generally made of rubber with a certain thickness so that the liquid bag A1 can use its own elasticity to shrink to achieve the simulation of the formation loss rate. Therefore, there needs to be enough liquid inside the liquid bag A1 to make it expand and then shrink. However, when the formation loss rate is too small, the liquid inside the liquid bag A1 will not be enough to expand the liquid bag A1, resulting in an insignificant shrinkage and thus unable to accurately simulate the formation loss.

[0067] For the second simulation method, assuming the diameter of the tunnel model to be simulated is 60 cm, so if it is required to control the formation loss rate between 0.5% - 3%, then the diameter variable of the tunnel model needs to be controlled within 1.5 mm - 9 mm. To achieve this purpose, the inner diameter of the small inner tube A4 needs to be set to 60 cm, and the outer diameter of the large outer tube A3 needs to be set to 60 cm + (1.5 - 9) cm. However, at this time, the wall thickness of the large outer tube A3 has reached 1 cm - 2 cm. Moreover, to avoid the large outer tube A3 being difficult to pull out after being sleeved with the small inner tube A4, a certain clearance allowance needs to be set between the large outer tube A3 and the small inner tube A4, which will cause the simulation variable of the tunnel model to far exceed 1.5 mm - 9 mm.

[0068] Furthermore, the above two simulation methods cannot achieve continuous changes in formation loss. Therefore, a third simulation method has been developed in the existing technology, such as Figure A-3As shown in the figure, the tunnel boring test device includes an iron sheet tunnel model A5 and a scaling device A6. The scaling device A6 is used to adjust the radial dimension of the iron sheet tunnel model A5 to simulate soil loss by changing the radial dimension of the iron sheet tunnel model A5.

[0069] However, the iron sheet tunnel model A5 is made by integrally forming iron sheets. So when the scaling device A6 controls the iron sheet tunnel model A5 to expand, it is actually forcibly stretching the iron sheet. As a result, it cannot ensure that the iron sheet tunnel model A5 remains circular after expansion, which is different from the situation where the tunnel lining at the construction site is circular, leading to the inability to achieve accurate experimental simulation at all.

[0070] In summary, the existing tunnel boring test devices mainly have two defects. One is the inability to achieve small-scale continuous simulation of the ground loss rate, and the other is the inability to accurately simulate the actual construction environment. Therefore, in order to solve the above two major problems, the present invention provides a tunnel boring test device for simulating small-scale ground loss, which will be specifically described in multiple embodiments below.

[0071] Embodiment 1

[0072] The first embodiment of the tunnel boring test device of the present invention is as Figures 1-1 to 1-5 shown, including a tunnel model 10 and a scaling mechanism 20. The tunnel model 10 is used to achieve deformation while maintaining a circular tube shape, and the scaling mechanism 20 is used to control the change of the radial dimension of the tunnel model 10.

[0073] Regarding the tunnel model 10, as Figures 1-1 to 1-5 shown, the tunnel model 10 includes a rigid arc-shaped plate 11 and a soft connector 12 that can be elastically deformed. Both opposite side walls of the rigid arc-shaped plate 11 are provided with splicing grooves 111, and the splicing grooves 111 extend along the axial direction of the rigid arc-shaped plate 11. Both opposite sides of the soft connector 12 are provided with connecting parts 121. Therefore, by installing the connecting parts 121 in the splicing grooves 111, four rigid arc-shaped plates 11 and four soft connectors 12 can be alternately connected into a circular tube shape.

[0074] Among them, the above-mentioned tunnel model 10 can be made by 3D printing technology to facilitate flexible production according to different experimental needs. For example, the rigid arc-shaped plate 11 can be made of high-toughness photosensitive resin to ensure that the rigid arc-shaped plate 11 has sufficient mechanical strength, while the soft connector 12 can be made of soft materials such as silica gel to ensure that the tunnel model 10 can achieve elastic expansion and contraction.

[0075] In addition, to strengthen the connection strength between the rigid arc plate 11 and the soft connector 12, in this embodiment, a plurality of fixing through holes 112 are provided on the groove wall of the splicing groove 111. The plurality of fixing through holes 112 all penetrate the inner surface of the rigid arc plate 11, and a fixing bolt 113 is installed in each of the plurality of fixing through holes 112. The fixing bolt 113 is in threaded connection with the fixing screw hole 123 of the soft connector 12. Therefore, the fixing bolt 113 can press the soft connector 12 inside the splicing groove 111, thereby preventing the phenomenon of loosening and separation between the rigid arc plate 11 and the soft connector 12.

[0076] Regarding the expansion and contraction mechanism 20, the expansion and contraction mechanism 20 is used to control the expansion and contraction of the tunnel model 10. As Figure 1-1 and Figure 1-2 shown, the expansion and contraction mechanism 20 includes a power output unit, a lead screw 22, a movable nut 23, a transmission rod 24, and a support plate 25. By connecting and driving each component, the effect of applying a radial pushing and pulling force to the tunnel model 10 can be achieved.

[0077] As Figure 1-1 and Figure 1-2 shown, in this embodiment, the above-mentioned power output unit is used to drive the lead screw 22 to rotate. Therefore, this purpose can be achieved by using the motor drive method. In this embodiment, it is preferably set that the power output unit includes a first support seat 211, a second support seat 212, a first bearing seat 213, a second bearing seat 214, a power output motor 215, a reducer 216, and a coupling 217. The first support seat 211 and the second support seat 212 are respectively arranged outside the two tunnel openings of the tunnel model 10 to support and hold the other components. The first bearing seat 213 is arranged on the first support seat 211, the second bearing seat 214 is arranged on the second support seat 212, and the first bearing seat 213, the second bearing seat 214, and the tunnel model 10 are arranged in a state where the hole axes coincide to support and fix the lead screw 22. The output shaft of the power output motor 215 is connected to the power input end of the reducer 216, the power output end of the reducer 216 is fixedly connected to one access end of the coupling 217, and the other access end of the coupling 217 is fixedly connected to one end of the lead screw 22 to control the low-speed rotation of the lead screw 22.

[0078] Among them, a vertically arranged fixing plate 218 is further provided on the first support seat 211, and a through hole is provided on the fixing plate 218. Therefore, after the power output motor 215 and the reducer 216 are assembled in a straight line, the reducer 216 can be fixedly installed on the fixing plate 218 and connected to the coupling 217 through the through hole of the fixing plate 218, so that the power output motor 215, the reducer 216, the coupling 217, and the lead screw 22 are connected by the simplest straight-line drive, ensuring the smooth and stable rotation of the power output unit driving the lead screw 22.

[0079] As Figure 1-1 and Figure 1-2 shown, in this embodiment, the above-mentioned lead screw 22 is arranged coaxially with the axis of the tunnel model 10. The peripheral wall of the middle part of the lead screw 22 is provided with an external thread, and both ends of the lead screw 22 are in the structure of a smooth rod; when installing the lead screw 22, the part with the external thread of the lead screw 22 is located inside the tunnel model 10, and both ends of the lead screw 22 extend outside the tunnel model 10 and are respectively rotatably installed in the first bearing block 213 and the second bearing block 214; among them, one end of the lead screw 22 passes through the first bearing block 213 and is fixedly connected to the coupling 217, thereby realizing the transmission connection between the lead screw 22 and the power output unit.

[0080] As Figure 1-1 and Figure 1-2 shown, in this embodiment, the above-mentioned movable nut 23 is sleeved outside the lead screw 22. The movable nut 23 is meshed with the external thread in the middle of the lead screw 22 through the internal thread in itself, so that the movable nut 23 and the lead screw 22 are in threaded connection, in order to realize the movement control of the movable nut 23 by using the lead screw 22; moreover, four first ear plates 231 are provided at both ends of the movable nut 23, and a total of eight first ear plates 231 are respectively arranged at the upper, lower, left and right positions at both ends of the movable nut 23, so as to facilitate the hinged connection with the transmission rod 24 by using the first ear plates 231.

[0081] As Figure 1-1 and Figure 1-2 shown, in this embodiment, there are a total of eight above-mentioned transmission rods 24. One ends of the eight transmission rods 24 are respectively hinged to the eight first ear plates 231, and the other ends of the eight transmission rods 24 are respectively hinged to the four support plates 25, so that the movable nut 23 realizes transmission in the up, down, left and right four directions respectively through two transmission rods 24 and a corresponding support plate 25.

[0082] Of course, the number of the transmission rods 24 is not limited. It only needs to ensure that multiple transmission rods 24 are arranged around the circumferential side of the movable nut 23, and multiple transmission rods 24 are all movably connected to the movable nut 23 to realize the force application control of the tunnel model 10. The actual set number can be adjusted according to the size of the tunnel model 10, the requirement of the regulation range, etc.

[0083] As Figure 1-1 and Figure 1-2 shown, in this embodiment, there are four above-mentioned support plates 25. The four support plates 25 are respectively fixedly connected to the inner walls of the four rigid arc-shaped plates 11, and two second ear plates 251 are provided on the inner surfaces of the four support plates 25, so the hinged connection with the transmission rod 24 can be realized by using the second ear plates 251.

[0084] Of course, there is no special restriction on the number of support plates 25. Generally, the number of support plates 25 is kept matching the number of rigid arc-shaped plates 11 to ensure that multiple support plates 25 are respectively connected and fixed to the inner walls of multiple rigid arc-shaped plates 11. Multiple support plates 25 are respectively movably connected to multiple transmission rods 24, and the actual set number can also be adjusted according to the size of the tunnel model 10, the required regulation range, etc.

[0085] When in application, the power output unit is used to drive the lead screw 22 to rotate self - sufficiently. The movable nut 23 will thus move back and forth. For example, if the translation of the movable nut 23 drives multiple transmission rods 24 to extend, the tunnel model 10 can be driven to expand accordingly. If the translation of the movable nut 23 drives multiple transmission rods 24 to retract, the tunnel model 10 can be driven to contract.

[0086] Obviously, after adopting the solution of this embodiment, at least the following beneficial effects are achieved:

[0087] First, with the mutual cooperation between the expansion - contraction mechanism 20 and the tunnel model 10, continuous change in the radial dimension of the tunnel model 10 can be realized. Not only does it improve the experimental efficiency without any demolition and replacement operations, but also continuous simulation of ground loss can be achieved.

[0088] Second, the rigid arc - shaped plates 11 provide guarantee for the mechanical strength of the tunnel model 10, while the soft connectors 12 enable elastic expansion and contraction regulation of the tunnel model 10. At this time, even if the expansion - contraction mechanism 20 is used to control the expansion and contraction of the tunnel model 10, the deformation of the soft connectors 12 has little impact on the overall shape of the tunnel model 10, ensuring that the tunnel model 10 can always maintain a circular tubular structure, that is, the shape of the tunnel model 10 is consistent with the shape of the tunnel lining, thus effectively solving the problem that the existing tunnel boring test device cannot accurately simulate the actual construction environment.

[0089] Embodiment Two

[0090] The second embodiment of the tunnel boring test device of the present invention is as Figures 2-1 to 2-3 shown. The difference from the first embodiment is that the soft connector 12 includes a straight groove part 122 and a connecting part 121. The straight groove part 122 is a linear groove - shaped structure. Connecting parts 121 are provided on both outer side walls of the straight groove part 122, and the connecting parts 121 are installed in the splicing grooves 111. Therefore, after adding the straight groove part 122, the two groove walls of the straight groove part 122 can be more easily bent inward, so that the deformation effect of the soft connector 12 is better and closer to the actual on - site construction environment.

[0091] Moreover, in the embodiment, the splicing grooves 111 and the connecting parts 121 are both convex-shaped in cross-section with matching dimensions. Therefore, after the connecting part 121 is fitted into the splicing groove 111, the splicing groove 111 and the soft connecting piece 12 assemble the tunnel model 10 into a radially anti-disengagement structure, thereby further strengthening the connection stability between the rigid arc-shaped plate 11 and the soft connecting piece 12.

[0092] Embodiment III

[0093] The third embodiment of the tunnel boring test device of the present invention is as Figure 3-1 shown. The difference from the second embodiment is that a limiting plate 26 is supported on the screw rod 22. The limiting plate 26 is arranged inside the tunnel model 10, and a limiting pin 252 is arranged on the supporting plate 25. The mutual cooperation of the limiting plate 26 and the limiting pin 252 is used to limit the expansion and contraction range of the tunnel model 10.

[0094] As Figure 3-1 shown, in this embodiment, the above-mentioned limiting plate 26 is in the shape of a circular plate with a perforation in the middle. Therefore, the screw rod 22 can pass through the perforation in the middle of the limiting plate 26 to achieve the through connection and installation between the two. At this time, the relationship between the two is only a socketing relationship, that is, the rotation of the screw rod 22 will not drive the limiting plate 26 to rotate; moreover, four straight groove-shaped limiting grooves 261 are provided on the limiting plate 26. The four limiting grooves 261 are respectively arranged at the top, bottom, left and right of the limiting plate 26, and each limiting groove 261 extends along the radial direction of the tunnel model 10 to facilitate the limitation of the expansion and contraction trajectory of the tunnel model 10.

[0095] Of course, the number of the limiting grooves 261 is not limited to four. It is only necessary to ensure that a plurality of limiting grooves 261 are provided on the limiting plate 26, and the plurality of limiting grooves 261 all extend along the radial direction of the tunnel model 10 to be able to realize the guiding and expansion and contraction range limitation of multiple rigid arc-shaped plates 11.

[0096] As Figure 3-1 shown, in this embodiment, to realize the installation of the above-mentioned limiting pin 252, mounting plates 253 are connected to the four supporting plates 25. The mounting plates 253 and the supporting plates 25 are connected in a perpendicular state so that the mounting plates 253 can extend towards the center of the tunnel model 10; moreover, limiting pins 252 are provided on the four mounting plates 253, and the four limiting pins 252 are respectively inserted into the four limiting grooves 261. The cooperation between the four limiting pins 252 and the four limiting grooves 261 is used to limit the expansion and contraction range of the tunnel model 10.

[0097] Of course, the number of the above-mentioned limiting pins 252 and mounting plates 253 is not limited to four, and can be adjusted according to the design requirements of the overall device.

[0098] Obviously, after adopting the above setting method, if the limit pin 252 abuts against the outer end of the limit groove 261, the maximum expansion size of the tunnel model 10 is restricted; if the limit pin 252 abuts against the inner end of the limit groove 261, the minimum contraction size of the tunnel model 10 is restricted, so that the expansion and contraction range of the tunnel model 10 is always maintained within a preset range, avoiding damage to the tunnel model 10 due to excessive expansion and contraction.

[0099] Embodiment 4

[0100] The fourth embodiment of the tunnel boring test device of the present invention is as Figures 4-1 to 4-7 shown. The difference from the third embodiment is that the tunnel boring test device further includes a first flexible sealing plate 31 and a second flexible sealing plate 32 that can be telescopically deformed. The first flexible sealing plate 31 and the second flexible sealing plate 32 respectively seal and cover the two tunnel openings of the tunnel model 10, so that when grouting operation needs to be carried out, the grouting liquid cannot enter the tunnel model 10.

[0101] As Figure 4-1 、 Figure 4-3 、 Figure 4-5 and Figure 4-6 shown, in this embodiment, the above-mentioned first flexible sealing plate 31 can be made of a flexible material such as silica gel. The first flexible sealing plate 31 is in the shape of a circular plate to facilitate fully covering the tunnel opening of the tunnel model 10; and there are two parts where the first flexible sealing plate 31 needs to be hermetically connected. One is the periphery of the first flexible sealing plate 31 and the periphery of the tunnel opening of the tunnel model 10, and the other is the connection part of the first flexible sealing plate 31 and the lead screw 22.

[0102] For the sealing connection between the periphery of the first flexible sealing plate 31 and the periphery of the tunnel opening of the tunnel model 10, in this embodiment, a plurality of through holes are provided on the periphery of the first flexible sealing plate 31, a plurality of threaded holes (specifically, these threaded holes are provided on the hard arc-shaped plate 11) are provided on the periphery of the tunnel opening of the tunnel model 10, and four first arc-shaped positioning plates 41 are provided. Each first arc-shaped positioning plate 41 is also provided with a plurality of through holes with matching positions.

[0103] Therefore, when installing the seal around the first flexible sealing plate 31, it should be ensured that the four first arc-shaped positioning plates 41 are all attached to the outer surface of the first flexible sealing plate 31, and the four first arc-shaped positioning plates 41 are respectively aligned with the four hard arc-shaped plates 11. Then, bolts are used to sequentially pass through the corresponding holes of the first arc-shaped positioning plate 41, the first flexible sealing plate 31, and are threadedly connected to the threaded holes of the hard arc-shaped plate 11, so that the first arc-shaped positioning plate 41, the first flexible sealing plate 31, and the hard arc-shaped plate 11 are fixedly connected by bolts, thus realizing the sealing connection between the periphery of the first flexible sealing plate 31 and the periphery of the tunnel opening of the tunnel model 10.

[0104] For the sealed connection between the first flexible sealing plate 31 and the lead screw 22, in this embodiment, a first shaft hole 311 is provided at the geometric center of the first flexible sealing plate 31, and a first sealing shaft sleeve 51 is provided on the first flexible sealing plate 31; the first sealing shaft sleeve 51 includes a first inner plate with holes 511, a first outer plate with holes 512 and a first sealing bearing 513. In the direction from the inside to the outside of the tunnel model 10, the first inner plate with holes 511, the first shaft hole 311 and the first outer plate with holes 512 are arranged in a state where the hole positions are coaxial. The first inner plate with holes 511, the first shaft hole 311 and the first outer plate with holes 512 are fixedly connected by bolts, and the first sealing bearing 513 is hermetically installed in the hole positions of the first inner plate with holes 511, the first shaft hole 311 and the first outer plate with holes 512. The lead screw 22 is hermetically sleeved inside the first sealing bearing 513, so that the sealed connection between the first flexible sealing plate 31 and the lead screw 22 is realized.

[0105] Similarly, as Figure 4-2 , Figure 4-4 , Figure 4-5 and Figure 4-7 shown, in this embodiment, the second flexible sealing plate 32 can be made of a flexible material such as silica gel. The second flexible sealing plate 32 is in the shape of a circular plate to facilitate the full coverage of the other tunnel opening of the tunnel model 10; there are two parts where the second flexible sealing plate 32 needs to be hermetically connected. One is the periphery of the second flexible sealing plate 32 and the periphery of the tunnel opening of the tunnel model 10, and the other is the connection part between the second flexible sealing plate 32 and the lead screw 22.

[0106] For the sealed connection between the periphery of the second flexible sealing plate 32 and the periphery of the tunnel opening of the tunnel model 10, in this embodiment, a plurality of through holes are provided at the periphery of the second flexible sealing plate 32, and a plurality of threaded holes (the threaded holes are also provided on the rigid arc-shaped plate 11) are provided at the periphery of the other tunnel opening of the tunnel model 10, and four second arc-shaped positioning plates 42 are provided. A plurality of through holes with matching positions are also provided on each second arc-shaped positioning plate 42.

[0107] Therefore, when hermetically installing the periphery of the second flexible sealing plate 32, it should be ensured that all four second arc-shaped positioning plates 42 are in contact with the outer surface of the second flexible sealing plate 32, and the four second arc-shaped positioning plates 42 are respectively aligned with the four rigid arc-shaped plates 11. Then, bolts are used to sequentially pass through the corresponding hole positions of the second arc-shaped positioning plates 42, the second flexible sealing plate 32, and are threadedly connected with the threaded holes of the rigid arc-shaped plate 11, so that the second arc-shaped positioning plates 42, the second flexible sealing plate 32 and the rigid arc-shaped plate 11 are fixedly connected by bolts, thus realizing the sealed connection between the periphery of the second flexible sealing plate 32 and the periphery of the other tunnel opening of the tunnel model 10.

[0108] For the sealed connection between the second flexible sealing plate 32 and the lead screw 22, in this embodiment, a second shaft hole 321 is provided at the geometric center of the second flexible sealing plate 32, and a second sealing shaft sleeve 52 is provided on the second flexible sealing plate 32; the second sealing shaft sleeve 52 includes a second perforated inner plate 521, a second perforated outer plate 522, and a second sealing bearing 523. In the direction from the inside to the outside of the tunnel model 10, the second perforated inner plate 521, the second shaft hole 321, and the second perforated outer plate 522 are arranged in a state where the hole positions are coaxial. The second perforated inner plate 521, the second shaft hole 321, and the second perforated outer plate 522 are fixedly connected by bolts, and the second sealing bearing 523 is hermetically installed in the hole positions of the second perforated inner plate 521, the second shaft hole 321, and the second perforated outer plate 522. The lead screw 22 is hermetically sleeved inside the second sealing bearing 523, so that the sealed connection between the second flexible sealing plate 32 and the lead screw 22 is realized.

[0109] Under certain experimental requirements, it is necessary to perform grouting operations outside the tunnel model 10. Therefore, after adopting the above setting method, the first flexible sealing plate 31 and the second flexible sealing plate 32 can make the inside of the tunnel model 10 in a sealed state, thereby preventing the grouting liquid from flowing into the tunnel model 10 and preventing the grouting liquid from damaging the expansion and contraction mechanism, that is, further expanding the application range of the tunnel boring test device in this embodiment.

[0110] Embodiment Five

[0111] The fifth embodiment of the tunnel boring test device of the present invention is as Figures 5-1 to 5-4 shown. The difference from the fourth embodiment is that first transparent baffles 61 and second transparent baffles 62 are respectively installed at both ends of the lead screw 22 outside the tunnel model 10.

[0112] As Figure 5-1 and Figure 5-3 shown, in this embodiment, the above-mentioned first transparent baffle 61 can be made of transparent materials such as acrylic, and the first transparent baffle 61 is in the shape of a circular plate. The diameter of the first transparent baffle 61 is larger than the maximum expansion size of the tunnel model 10, so as to facilitate the first transparent baffle 61 to always hermetically cover the first flexible sealing plate 31. At this time, not only can it prevent the sandy slurry during the experiment from damaging the first flexible sealing plate 31, but also it is convenient for experimental personnel to observe the environmental conditions outside the tunnel at all times; in addition, in order to strengthen the sealing between the first transparent baffle 61 and the first flexible sealing plate 31, in this embodiment, a first annular backing plate 71 is hermetically clamped between the periphery of the first transparent baffle 61 and the first flexible sealing plate 31 to ensure a tighter connection between the two.

[0113] Similarly, as Figure 5-2 and Figure 5-4As shown, in this embodiment, the second transparent baffle 62 can be made of a transparent material such as acrylic, and the second transparent baffle 62 is in the shape of a circular plate. The diameter of the second transparent baffle 62 is larger than the maximum expansion size of the tunnel model 10, so that it is convenient for the second transparent baffle 62 to always seal and cover the second flexible sealing plate 32. At this time, not only can the sandy slurry during the experiment be prevented from damaging the second flexible sealing plate 32, but also it is convenient for the experimenter to observe the environmental conditions outside the tunnel at all times. In addition, in order to strengthen the sealing between the second transparent baffle 62 and the second flexible sealing plate 32, a second annular backing plate 72 is hermetically clamped between the peripheries of the second transparent baffle 62 and the second flexible sealing plate 32 in this embodiment to ensure a closer connection between the two.

[0114] Embodiment Six

[0115] The sixth embodiment of the tunnel boring test device of the present invention is as Figures 6-1 to 6-3 shown, and the difference from the fifth embodiment is that grouting holes 114 are provided on the surface of the rigid arc plate 11. The grouting holes 114 penetrate through the rigid arc plate 11, and a plurality of grouting joints 312 are provided on the first flexible sealing plate 31. The plurality of grouting joints 312 are respectively connected to the plurality of grouting holes 114 through pipelines. That is, at this time, the grouting operation can be realized by using the tunnel boring test device, and its application method is roughly as follows:

[0116] S1. Fill the soil in the experimental box until the soil reaches the lower part of the preset installation position of the tunnel model 10, stop adding soil, then place the tunnel model 10 on the added soil, and use the expansion and contraction mechanism 20 to control the diameter of the tunnel model 10 to reach the maximum value. After the relevant lines are led out of the experimental box, continue to fill the soil until the soil reaches the designed height in the test.

[0117] S2. Through the external console, gradually converge the diameter of the tunnel model 10 at the test-set rate until the test-predetermined ground loss situation is reached to simulate the ground loss situation during tunnel excavation. During this process, at the same time, through the grouting equipment, inject the slurry into the grouting holes 114 according to the test-set grouting pressure to simulate the backfill grouting working condition.

[0118] S3. Change the ground loss rate and grouting pressure respectively, and repeat steps S1 and S2.

[0119] S4. By observing and recording the data of various sensors, obtain the tunnel floating and the situation of the slurry pressure on the tunnel under different ground losses and different grouting pressure conditions, so as to guide the actual project.

[0120] In summary, after adopting this setting method, the grouting equipment can be connected to the grouting joint 312, and the generated slurry will flow through the grouting joint 312 and the grouting holes 114 in sequence and then be discharged to the outside of the circumference of the tunnel model 10. This setting method not only endows the tunnel boring test device with the grouting function, but also ensures that the slurry can directly cover the surface of the tunnel model 10, and its grouting effect is much better than that of perfusion from the outside by using equipment.

[0121] Of course, there may be different grouting requirements during the experiment. Therefore, in this embodiment, multiple grouting holes 114 are evenly distributed at various parts of the tunnel model 10, so that the experimenter can choose to connect different grouting holes 114 according to different experimental requirements.

[0122] It should be noted that after adding the grouting joint 312, corresponding holes should also be opened on the first transparent baffle 61 so that the external grouting equipment can be connected to the grouting joint 312.

[0123] Embodiment Seven

[0124] The seventh embodiment of the tunnel boring test device of the present invention is as Figure 7-1 shown. The difference from the sixth embodiment is that a sensor mounting hole 115 is provided on the outer surface of the hard arc-shaped plate 11, and a pressure sensor 116 is provided in the sensor mounting hole 115.

[0125] During the experiment, corresponding sensors can be set for pressure monitoring, and the sensors can be set independently of the experimental equipment; after adopting the setting method of this embodiment, the pressure sensor 116 can be integrated into the tunnel boring test device, thereby improving the convenience during the experiment, and the setting of the sensor mounting hole 115 also makes the setting of the pressure sensor 116 more firm, and provides a guarantee for accurately monitoring the pressure at the required position.

[0126] Of course, multiple pressure monitors may be required during the experiment. Therefore, this embodiment is provided with multiple groups of sensor mounting holes 115 and pressure sensors 116, and the multiple groups of sensor mounting holes 115 and pressure sensors 116 are distributed at various parts of the outer surface of the tunnel model 10 to facilitate the pressure monitoring requirements in various situations.

[0127] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A tunnel boring test device for simulating small - amplitude ground loss, characterized in that, It includes a tunnel model and a telescoping mechanism; The tunnel model includes rigid arc-shaped plates and soft connectors that can be telescopically deformed. Multiple rigid arc-shaped plates and multiple soft connectors are alternately connected into a circular tube shape; The telescoping mechanism is used to control the expansion and contraction of the tunnel model. The telescoping mechanism includes a power output unit, a lead screw, a movable nut, a transmission rod, and a support plate; The power output unit is used to drive the lead screw to rotate self; The lead screw is arranged coaxially with the axis of the tunnel model; The movable nut is sleeved outside the lead screw, and the movable nut is threadedly connected to the lead screw; Multiple transmission rods are arranged around the circumference of the movable nut, and multiple transmission rods are all movably connected to the movable nut; Multiple support plates are respectively fixedly connected to the inner walls of multiple rigid arc-shaped plates, and multiple support plates are respectively movably connected to multiple transmission rods; The tunnel boring test device also includes a first flexible sealing plate and a second flexible sealing plate that can be telescopically deformed. The first flexible sealing plate and the second flexible sealing plate respectively seal and cover the two tunnel openings of the tunnel model; And a first sealing shaft sleeve is provided on the first flexible sealing plate, a second sealing shaft sleeve is provided on the second flexible sealing plate, and the two ends of the lead screw are respectively inserted into the first sealing shaft sleeve and the second sealing shaft sleeve; First transparent baffles and second transparent baffles are respectively installed at the two ends of the lead screw outside the tunnel model; The first transparent baffle seals and covers the first flexible sealing plate, and a first annular cushion plate is hermetically clamped between the first transparent baffle and the periphery of the first flexible sealing plate; The second transparent baffle seals and covers the second flexible sealing plate, and a second annular cushion plate is hermetically clamped between the second transparent baffle and the periphery of the second flexible sealing plate; Grouting holes are provided on the surface of the rigid arc-shaped plate, and the grouting holes penetrate through the rigid arc-shaped plate; Multiple grouting joints are provided on the first flexible sealing plate, and multiple grouting joints are respectively connected to multiple grouting holes through pipelines; Sensor mounting holes are provided on the outer surface of the rigid arc-shaped plate, and pressure sensors are provided in the sensor mounting holes.

2. The tunnel boring test device according to claim 1, characterized in that, Splicing grooves are provided on both opposite side walls of the rigid arc-shaped plate, and the splicing grooves extend along the axial direction of the rigid arc-shaped plate; The soft connector includes a straight groove portion and a connecting portion. The straight groove portion is a linear groove structure, and connecting portions are provided on both outer side walls of the straight groove portion. The connecting portions are installed in the splicing grooves.

3. The tunnel boring test device according to claim 2, characterized in that, The cross-sections of the splicing groove and the connecting portion are both convex shapes with matching dimensions. The splicing groove and the connecting portion assemble the tunnel model into a radially anti-disconnection structure; Multiple fixing through holes are provided on the groove wall of the splicing groove. Multiple fixing through holes all penetrate through the inner surface of the rigid arc-shaped plate. Multiple fixing bolts are installed in multiple fixing through holes, and the fixing bolts are threadedly connected to the fixing screw holes of the soft connector.

4. The tunnel boring test device according to claim 1, characterized in that, A limiting plate is supported on the lead screw. The limiting plate is arranged inside the tunnel model. Multiple limiting grooves are provided on the limiting plate, and multiple limiting grooves all extend along the radial direction of the tunnel model; Mounting plates are connected to multiple of the support plates, and limit pins are provided on multiple of the mounting plates. Multiple of the limit pins are respectively inserted into multiple of the limit grooves, and the cooperation between multiple of the limit pins and multiple of the limit grooves is used to limit the expansion and contraction range of the tunnel model.

5. The tunnel boring test device according to claim 1, characterized in that, The tunnel boring test device further includes a first arc-shaped positioning plate and a second arc-shaped positioning plate; Multiple of the first arc-shaped positioning plates are all attached to the outer surface of the first flexible sealing plate, and multiple of the first arc-shaped positioning plates are respectively arranged in alignment with multiple of the rigid arc-shaped plates. The first arc-shaped positioning plate, the first flexible sealing plate and the rigid arc-shaped plate are bolted and fixed; Multiple of the second arc-shaped positioning plates are all attached to the outer surface of the second flexible sealing plate, and multiple of the second arc-shaped positioning plates are respectively arranged in alignment with multiple of the rigid arc-shaped plates. The second arc-shaped positioning plate, the second flexible sealing plate and the rigid arc-shaped plate are bolted and fixed.

6. The tunnel boring test device according to claim 1, characterized in that, A first shaft hole is provided at the geometric center of the first flexible sealing plate, and a second shaft hole is provided at the geometric center of the second flexible sealing plate; The first sealing shaft sleeve includes a first inner plate with holes, a first outer plate with holes and a first sealing bearing. In the direction from the inside to the outside of the tunnel model, the first inner plate with holes, the first shaft hole and the first outer plate with holes are arranged in a state where the hole positions are coaxial, and the first inner plate with holes, the first shaft hole and the first outer plate with holes are bolted and fixed; the first sealing bearing is hermetically installed in the hole positions of the first inner plate with holes, the first shaft hole and the first outer plate with holes, and the lead screw is hermetically sleeved inside the first sealing bearing; The second sealing shaft sleeve includes a second inner plate with holes, a second outer plate with holes and a second sealing bearing. In the direction from the inside to the outside of the tunnel model, the second inner plate with holes, the second shaft hole and the second outer plate with holes are arranged in a state where the hole positions are coaxial, and the second inner plate with holes, the second shaft hole and the second outer plate with holes are bolted and fixed; the second sealing bearing is hermetically installed in the hole positions of the second inner plate with holes, the second shaft hole and the second outer plate with holes, and the lead screw is hermetically sleeved inside the second sealing bearing.

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