A tunneling test device simulating soil excavation and unloading

Abstract

The invention discloses a tunnel excavation test device for simulating soil excavation and unloading, which relates to the technical field of tunnel excavation tests and mainly comprises a tunnel model, a supporting mechanism, a lifting mechanism and a pressure sensor; wherein the lifting mechanism uses the supporting mechanism to realize connection and fixation with the tunnel model, so under the mutual transmission of various components, this scheme can realize the lifting and lowering control of the tunnel model by utilizing the expansion and contraction changes of the hydraulic cylinder of the lifting mechanism, for example, when the tunnel model is controlled to descend, the state of the soil before excavation can be simulated, and then when the tunnel model is controlled to rise, the phenomenon of soil excavation and unloading can be simulated, and because the pressure sensor can perform corresponding pressure monitoring, it is only necessary to adjust the expansion and contraction degree of the hydraulic cylinder to accurately simulate the conditions of different soil excavation and unloading weights, that is, the problem that the existing experimental device cannot accurately simulate the soil excavation and unloading weight is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel excavation tests, and in particular to a tunnel excavation test device for simulating soil excavation and unloading. Background Art

[0002] In recent years, shield tunnels have been widely used in the construction of subway tunnels. Due to the difference between the weight of the shield and the weight of the soil before excavation, the shield construction process will produce excavation unloading phenomenon, which will cause the soil under the shield to rebound.

[0003] It should be noted that if the soil rebound caused by excavation unloading is not controlled, it will cause serious engineering geological disasters such as ground subsidence on the one hand, and on the other hand, it may also cause segment misalignment and other phenomena that affect construction safety and progress. Therefore, it is necessary to carry out indoor tests to simulate the phenomenon of soil excavation unloading during tunnel excavation construction, and more realistically simulate the phenomena that may occur during shield construction, so as to determine how to select construction parameters in actual projects.

[0004] In order to achieve this goal, the existing technology uses a method of arranging water bags inside the tunnel lining to realize simulation. For example, at the beginning, the water bags inside the tunnel are filled with water, which will generate pressure on the tunnel lining and the soil below. When the tunnel excavation needs to simulate excavation and unloading, the water in the water bags is discharged. At this time, the force on the tunnel lining and the soil below will disappear, thereby simulating the excavation and unloading phenomenon.

[0005] However, if water bags are used for simulation, since the density of water is much smaller than the density of soil and the volume inside the tunnel is constant, the weight of the same volume of water is much smaller than the weight of soil, so the weight of excavation unloading cannot be accurately simulated.

[0006] To this end, developing an experimental device that can accurately simulate the weight of soil excavation and unloading has become a technical problem that needs to be solved urgently. Summary of the invention

[0007] The purpose of the present invention is to provide a tunnel boring test device for simulating soil excavation and unloading, so as to solve the problem that the existing experimental device cannot accurately simulate the weight of soil excavation and unloading.

[0008] In order to solve the above technical problems, the present invention provides a tunnel excavation test device for simulating soil excavation and unloading, comprising a tunnel model, a supporting mechanism and a lifting mechanism; the supporting mechanism comprises a central axis and a supporting rod; the axial direction of the central axis is consistent with the axial direction of the tunnel model, and the central axis passes through the tunnel model; at least one supporting rod is connected between the outer wall of the central axis and the inner wall of the tunnel model; the lifting mechanism is placed outside the tunnel model, and the lifting mechanism comprises a connecting seat, a base, and a hydraulic cylinder and a pressure sensor arranged on the base; the connecting seat is arranged above the base, and the connecting seat is connected to the central axis; the telescopic end of the hydraulic cylinder is connected to the connecting seat, and the hydraulic cylinder is used to drive the connecting seat to move up and down; the pressure sensor is arranged below the connecting seat, and the pressure sensor is used to abut against the bottom of the connecting seat for pressure monitoring.

[0009] In one embodiment, both ends of the central axis extend out of the tunnel model, and both ends of the central axis are connected to the lifting mechanism.

[0010] In one embodiment, the tunnel excavation test device also includes a model box, and the two opposite box walls of the model box are respectively provided with a first transparent baffle and a second transparent baffle, the first transparent baffle is provided with a first through hole passing through it, and the second transparent baffle is provided with a second through hole passing through it, and the diameters of the first through hole and the second through hole are both larger than the diameter of the central axis; the tunnel model is arranged in the model box, and the tunnel model is placed between the first transparent baffle and the second transparent baffle; the two ends of the central axis respectively pass through the first through hole and the second through hole to connect with the lifting mechanism.

[0011] In one of the embodiments, the tunnel wall of the tunnel model is provided with a grouting hole passing through it, and the two tunnel openings of the tunnel model are respectively covered with a first flexible sealing plate and a second flexible sealing plate that can be retracted and deformed; the first flexible sealing plate is arranged opposite to the first transparent baffle, and a first sealing sleeve is provided on the first flexible sealing plate; the second flexible sealing plate is arranged opposite to the second transparent baffle, and a second sealing sleeve is provided on the second flexible sealing plate; a grouting joint is provided on the first transparent baffle, and the grouting joint passes through the first flexible sealing plate and is connected to the grouting hole, and the grouting joint and the first flexible sealing plate are sealed; the two ends of the central axis are respectively inserted into the first sealing sleeve and the second sealing sleeve, and the central axis and the first through hole and the second through hole are both movable elastically sealed.

[0012] In one embodiment, a first axial hole is provided at the geometric center of the first flexible sealing plate, and a second axial hole is provided at the geometric center of the second flexible sealing plate; the first sealing sleeve comprises a first inner plate with a hole, a first outer plate with a hole and a first sealing bearing, and in the direction from the inside to the outside of the tunnel model, the first inner plate with a hole, the first axial hole and the first outer plate with a hole are sequentially arranged in a state of coaxial hole positions, and the first inner plate with a hole, the first axial hole and the first outer plate with a hole are fixed by bolts; the first sealing bearing is sealingly installed on the first inner plate with a hole, the first axial hole and the first outer plate with a hole The central axis is sealedly sleeved in the hole position of the outer plate with a hole; the second sealed shaft sleeve includes a second inner plate with a hole, a second outer plate with a hole and a second sealed bearing. In the direction from the inside to the outside of the tunnel model, the second inner plate with a hole, the second axial hole and the second outer plate with a hole are sequentially arranged in a state where the holes are coaxial, and the second inner plate with a hole, the second axial hole and the second outer plate with a hole are connected and fixed by bolts; the second sealed bearing is sealed and installed in the hole position of the second inner plate with a hole, the second axial hole and the second outer plate with a hole, and the central axis is sealedly sleeved in the second sealed bearing.

[0013] In one of the embodiments, a third flexible sealing plate that can be retracted and deformed is provided in the first through hole, a third sealing sleeve is provided on the third flexible sealing plate, and the central axis is sealedly connected inside the third sealing sleeve; a fourth flexible sealing plate that can be retracted and deformed is provided in the second through hole, a fourth sealing sleeve is provided on the fourth flexible sealing plate, and the central axis is sealedly connected inside the fourth sealing sleeve.

[0014] In one embodiment, the first through hole and the second through hole are stepped holes, and the tunnel excavation test device also includes a first pressure ring and a second pressure ring; the periphery of the third flexible sealing plate is clamped between the step surface of the first through hole and the first pressure ring, and the first pressure ring and the step surface of the first through hole are fixed by bolts; the periphery of the fourth flexible sealing plate is clamped between the step surface of the second through hole and the second pressure ring, and the second pressure ring and the step surface of the second through hole are fixed by bolts.

[0015] In one embodiment, a third axial hole is provided at the geometric center of the third flexible sealing plate, and a fourth axial hole is provided at the geometric center of the fourth flexible sealing plate; the third sealing sleeve includes a third inner plate with holes, a third outer plate with holes and a third sealed bearing, and in the direction from the inside to the outside of the tunnel model, the third inner plate with holes, the third axial hole and the third outer plate with holes are arranged in sequence in a state of coaxial hole positions, and the third inner plate with holes, the third axial hole and the third outer plate with holes are fixed by bolts; the third sealed bearing is sealably installed on the third inner plate with holes, the third axial hole and the third outer plate with holes The central axis is connected to the sealing sleeve in the hole position of the outer plate with a hole; the fourth sealing sleeve includes a fourth inner plate with a hole, a fourth outer plate with a hole and a fourth sealed bearing. In the direction from the inside to the outside of the tunnel model, the fourth inner plate with a hole, the fourth axial hole and the fourth outer plate with a hole are sequentially arranged in a state of coaxial hole positions, and the fourth inner plate with a hole, the fourth axial hole and the fourth outer plate with a hole are connected and fixed by bolts; the fourth sealed bearing is seal-mounted in the hole position of the fourth inner plate with a hole, the fourth axial hole and the fourth outer plate with a hole, and the central axis is connected to the sealing sleeve in the fourth sealed bearing.

[0016] In one embodiment, a plurality of the support rods are arranged around the circumference of the central axis, and the plurality of the support rods are connected between the outer wall of the central axis and the inner wall of the tunnel model.

[0017] In one embodiment, a guide flange and a vertically arranged column are provided on the top of the base, the pressure sensor is provided on the top of the column, a vertically arranged guide rod is inserted in the guide flange, and the guide rod is connected and fixed to the bottom of the connecting seat.

[0018] The beneficial effects of the present invention are as follows:

[0019] Since the telescopic end of the hydraulic cylinder is connected to the connecting seat, the hydraulic cylinder is used to drive the connecting seat to move up and down. Therefore, under the mutual transmission of various components, this scheme can use the telescopic change of the hydraulic cylinder to realize the lifting and lowering control of the tunnel model. For example, when the tunnel model is controlled to descend, the tunnel model has a large force on the soil below, which can simulate the state of the soil before excavation. Then, when the tunnel model is controlled to rise, the force of the tunnel model on the soil below gradually decreases, which can simulate the phenomenon of soil excavation and unloading. In addition, since the pressure sensor is arranged below the connecting seat, the pressure sensor is used to abut against the bottom of the connecting seat for pressure monitoring. Therefore, it is only necessary to adjust the telescopic degree of the hydraulic cylinder to accurately simulate the conditions of different soil excavation and unloading weights, which effectively solves the problem that the existing experimental device cannot accurately simulate the soil excavation and unloading weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1-1 It is a structural schematic diagram provided by Embodiment 1 of the present invention;

[0022] Figure 1-2 yes Figure 1-1 A side view schematic diagram of the structure;

[0023] Figure 2-1 It is a structural schematic diagram provided by Embodiment 2 of the present invention;

[0024] Figure 3-1 It is a structural diagram provided by Embodiment 3 of the present invention;

[0025] Figure 4-1 is a front view structural diagram provided by Embodiment 4 of the present invention;

[0026] Figure 4-2 yes Figure 4-1 A rear view structural diagram of ;

[0027] Figure 4-3 yes Figure 4-1 A schematic diagram of a top view structure;

[0028] Figure 5-1 is a front view structural diagram provided by Embodiment 5 of the present invention;

[0029] Figure 5-2 yes Figure 5-1 A rear view structural diagram of ;

[0030] Figure 5-3 yes Figure 5-1 Schematic diagram of the tunnel model structure;

[0031] Figure 5-4 yes Figure 5-3 A rear view structural diagram of ;

[0032] Figure 5-5 yes Figure 5-3 A schematic structural diagram of the first flexible sealing plate;

[0033] Figure 5-6 yes Figure 5-4 A schematic structural diagram of a second flexible sealing plate;

[0034] Figure 5-7 yes Figure 5-1 A schematic diagram of a side cross-sectional structure;

[0035] Figure 5-8 yes Figure 5-7 A schematic diagram of the enlarged structure of part A;

[0036] Figure 5-9 yes Figure 5-7 A schematic diagram of the enlarged structure of part B in FIG.

[0037] Figure 5-10 yes Figure 5-3 A schematic diagram of the structure of the third flexible sealing plate;

[0038] Figure 5-11 yes Figure 5-4 A schematic structural diagram of a fourth flexible sealing plate;

[0039] Figure 5-12 yes Figure 5-3 A schematic diagram of a side cross-sectional structure.

[0040] The reference numerals are as follows:

[0041] 10. Tunnel model; 11. Grouting hole;

[0042] 20. Support mechanism; 21. Middle shaft; 22. Support rod; 23. Movable nut; 24. Extension motor;

[0043] 30. Lifting mechanism; 31. Connecting seat; 32. Base; 33. Hydraulic cylinder; 34. Pressure sensor; 35. Positioning bearing seat; 36. Guide flange; 37. Column; 38. Guide rod;

[0044] 40. Model box; 41. First transparent baffle; 411. First through hole; 42. Second transparent baffle; 421. Second through hole;

[0045] 51, first flexible sealing plate; 511, first axial hole; 52, second flexible sealing plate; 521, second axial hole; 53, third flexible sealing plate; 531, third axial hole; 54, fourth flexible sealing plate; 541, fourth axial hole;

[0046] 61. first sealing sleeve; 611. first inner plate with holes; 612. first outer plate with holes; 613. first sealed bearing; 62. second sealing sleeve; 621. second inner plate with holes; 622. second outer plate with holes; 623. second sealed bearing; 63. third sealing sleeve; 631. third inner plate with holes; 632. third outer plate with holes; 633. third sealed bearing; 64. fourth sealing sleeve; 641. fourth inner plate with holes; 642. fourth outer plate with holes; 643. fourth sealed bearing;

[0047] 70. Grouting joints;

[0048] 81. a first arc-shaped positioning plate; 82. a second arc-shaped positioning plate;

[0049] 91. First pressure ring; 92. Second pressure ring. DETAILED DESCRIPTION

[0050] 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.

[0051] In the prior art, the experimental method is to use a water bag for simulation, and this simulation method is mainly used to study the soil rebound phenomenon caused by excavation unloading.

[0052] The above-mentioned excavation unloading phenomenon specifically refers to the fact that in the unexcavated soil layer, the upper soil will exert force on the lower soil, and the lower soil will be compressed due to the force; and as the tunnel is excavated, the upper soil will be excavated away. At this time, the lining has not been installed yet, so the force originally exerted on the lower soil by the upper soil will disappear. This is the excavation unloading phenomenon.

[0053] The soil rebound phenomenon mentioned above specifically refers to the fact that the lower soil was originally compressed by the force of the upper soil. At this time, the force disappears, just like a compressed spring will return to its original shape when the compression force is removed. The soil is similar. It was originally compressed, and when the compression force is removed, it will tend to return to its original shape. This is the soil rebound phenomenon.

[0054] However, the above-mentioned airbag test method has many disadvantages, such as:

[0055] First, if water bags are used for simulation, since the density of water is much smaller than the density of soil, and the volume inside the tunnel is constant, the weight of the same volume of water is much smaller than the weight of soil, so the weight of excavation unloading cannot be accurately simulated.

[0056] Second, this method will take up a lot of space in the tunnel, making it difficult to arrange other experimental equipment such as grouting.

[0057] Third, if water bags are used to simulate excavation and unloading, each experiment needs to be refilled with water and drained, which is more troublesome.

[0058] Especially for the first problem mentioned above, the accuracy of the experiment has been seriously affected. Once the experiment produces an erroneous guiding effect, it will bring serious potential risks to the actual construction in the future. Therefore, in order to solve this problem, the present invention discloses a tunnel excavation test device for simulating soil excavation and unloading, which mainly includes a tunnel model, a supporting mechanism, a lifting mechanism and a pressure sensor; wherein the lifting mechanism uses the supporting mechanism to realize the connection and fixation with the tunnel model, so under the mutual transmission of each component, this scheme can realize the lifting and lowering control of the tunnel model by using the expansion and contraction change of the hydraulic cylinder of the lifting mechanism. For example, when the tunnel model is controlled to descend, the tunnel model has a large force on the soil below, which can simulate the state of the soil before excavation. Then, when the tunnel model is controlled to rise, the force of the tunnel model on the soil below gradually decreases, which can simulate the phenomenon of soil excavation and unloading. Moreover, since the pressure sensor can perform corresponding pressure monitoring, it is only necessary to adjust the expansion and contraction degree of the hydraulic cylinder to accurately simulate the situation of different soil excavation and unloading weights, that is, the problem that the existing experimental device cannot accurately simulate the soil excavation and unloading weight is effectively solved.

[0059] In order to better illustrate this solution, it will be explained in combination with a number of specific embodiments below.

[0060] Embodiment 1

[0061] The present invention discloses a tunneling test device for simulating soil excavation and unloading, wherein the first embodiment Figure 1-1 and Figure 1-2 As shown, it includes a tunnel model 10, a supporting mechanism 20 and a lifting mechanism 30. The tunnel model 10 is used to simulate a shield device, the supporting mechanism 20 is used to realize the linkage between the tunnel model 10 and the lifting mechanism 30, and the lifting mechanism 30 is used to realize the lifting control of the tunnel model 10.

[0062] Regarding the tunnel model 10, Figure 1-1 As shown, its shape is tubular, and its radial dimension is large and its axial dimension is small. Therefore, after adopting this setting method, it can not only meet the simulation requirements of the shield device, but also reduce the occupied space of the tunnel model 10; wherein, the tunnel model 10 generally has no special material restriction requirements, but when producing and designing the tunnel model 10, it should be ensured that the tunnel model 10 has sufficient mechanical strength to avoid the tunnel model 10 being damaged by pressure during the experiment.

[0063] Regarding the support mechanism 20, since its function is to realize the linkage between the tunnel model 10 and the lifting mechanism 30, there is generally no special restriction on its appearance, as long as the support mechanism 20 can realize the requirement of serving as a transfer connection component; however, in order to reduce unnecessary volume occupation and ensure the connection strength between the tunnel model 10 and the support mechanism 20, this embodiment preferably sets the support mechanism 20 as follows Figure 1-1 and Figure 1-2 As shown, the support mechanism 20 at this time includes a central axis 21 and a support rod 22; wherein, the axial direction of the central axis 21 is consistent with the axial direction of the tunnel model 10, both are arranged horizontally, and the central axis 21 passes through the tunnel model 10 so that the end of the central axis 21 is placed outside the tunnel model 10; and the support rod 22 is one, and the support rod 22 is connected between the outer wall of the central axis 21 and the inner wall of the bottom of the tunnel model 10, and the support rod 22 is arranged vertically.

[0064] Of course, there is no special limit to the number of support rods 22. It is only necessary to ensure that at least one support rod 22 is connected between the outer wall of the central axis 21 and the inner wall of the tunnel model 10, so that a stable connection between the tunnel model 10 and the central axis 21 can be achieved.

[0065] The lifting mechanism 30 is used to realize the lifting control of the tunnel model 10. Generally speaking, most conventional lifting structures can also meet this requirement. However, considering that the experimental environment has a strong pressure resistance and the relevant pressure monitoring needs to be realized, the lifting mechanism 30 is preferably set as follows in this embodiment. Figure 1-1 and Figure 1-2 As shown, the lifting mechanism 30 is placed outside the tunnel model 10, and the lifting mechanism 30 includes a connecting seat 31, a base 32, and a hydraulic cylinder 33 and a pressure sensor 34 arranged on the base 32; the connecting seat 31 is arranged above the base 32, and the connecting seat 31 is connected to the central axis 21. Specifically, a positioning bearing seat 35 is provided on the connecting seat 31 at this time, so the positioning bearing seat 35 can be used to sleeve the outside of the central axis 21 to achieve the connection and fixation between the two; and the hydraulic cylinder 33 is fixed on the base 32 in a vertical arrangement, and the upper part of the hydraulic cylinder 33 is vertically movable. The telescopic end is telescopic, so after the telescopic end of the hydraulic cylinder 33 is connected to the connecting seat 31, the hydraulic cylinder 33 can be used to drive the connecting seat 31 to move up and down; and the pressure sensor 34 is arranged below the connecting seat 31, so the pressure sensor 34 at this time will be placed in the lifting trajectory of the connecting seat 31, and according to the lifting and lowering movement of the connecting seat 31, the connection seat 31 and the pressure sensor 34 can be controlled to separate, abut, and adjust the abutment state to different degrees, so that the pressure sensor 34 can be used to abut against the bottom of the connecting seat 31 for pressure monitoring.

[0066] In order to ensure smooth lifting and lowering control and accurate pressure monitoring, this embodiment also preferably sets the lifting mechanism 30 as Figure 1-1 and Figure 1-2 As shown, at this time, a guide flange 36 and a vertically arranged column 37 are provided on the top of the base 32, a pressure sensor 34 is provided on the top of the column 37, a vertically arranged guide rod 38 is inserted in the guide flange 36, and the guide rod 38 is connected and fixed to the bottom of the connecting seat 31.

[0067] Therefore, after adopting this setting method, the column 37 will enable the pressure sensor 34 to be closer to the connecting seat 31, so that the pressure sensor 34 can more accurately monitor the pressure generated by the slight movement of the tunnel model 10; and the coordinated setting of the guide flange 36 and the guide rod 38 limits the vertical movement trajectory of the connecting seat 31, so as to ensure that the lifting and lowering movement of the tunnel model 10 is more stable and smooth.

[0068] When experimental simulation is required, its application is roughly as follows:

[0069] S1, first fill the box with soil until the soil reaches the lower part of the originally simulated tunnel, stop adding soil, place the tunnel model 10 on the added soil, use the lifting mechanism 30 to control the tunnel model 10 to descend, and after the connecting seat 31 is in contact with the pressure sensor 34, by monitoring the corresponding pressure information, adjust the pressure on the tunnel model 10 to be consistent with the soil force to be simulated, and then lead the relevant lines out of the box, and continue filling until the soil reaches the height designed in the test.

[0070] S2, controlling the tunnel model 10 to gradually rise at a rate set in the experiment, so that the pressure on the tunnel model 10 is gradually unloaded until only the self-weight of the tunnel model 10 remains, thereby accurately simulating the unloading of soil excavation during tunnel excavation.

[0071] It should also be pointed out that when different soil bodies are used for testing, the weight of the soil body to be simulated for excavation and unloading is also different. Therefore, after adopting the tunnel excavation test device provided in this embodiment, the monitoring results of the pressure sensor can be monitored in real time to accurately adjust the applied pressure value to meet the usage requirements in different situations.

[0072] Embodiment 2

[0073] The second embodiment of the tunnel excavation test device of the present invention is basically the same as the first embodiment. Figure 2-1 As shown, the difference is that there are eight support rods 22 at this time, and every two support rods 22 form a group, which are arranged at four places above, below, left and right of the central axis 21, and the two ends of each support rod 22 are respectively connected and fixed to the outer wall of the central axis 21 and the inner wall of the tunnel model 10.

[0074] Therefore, after adopting this setting method, the tunnel model 10 can be connected and fixed with the central axis 21 by using the support rods 22 in all directions, so that the connection between the tunnel model 10 and the central axis 21 is more stable, and the support rods 22 can also be used to support the tunnel model 10 outward, so as to avoid the problem of the tunnel model 10 being easily damaged by force deformation during the experiment.

[0075] Of course, the arrangement of the support rods 22 is not limited to this. It is only necessary to ensure that multiple support rods 22 are arranged around the circumference of the central axis 21, and multiple support rods 22 are connected between the outer wall of the central axis 21 and the inner wall of the tunnel model 10, so as to achieve the above-mentioned beneficial effects. Technical personnel in this field can make appropriate adjustments according to actual needs.

[0076] Embodiment 3

[0077] The third embodiment of the tunnel excavation test device of the present invention is basically the same as the second embodiment. Figure 3-1 As shown, the difference is that both ends of the central axis 21 pass through the outside of the tunnel model 10, and both ends of the central axis 21 are connected to the lifting mechanism 30.

[0078] Compared with the case where only one lifting mechanism 30 is provided, this embodiment utilizes two lifting mechanisms 30 to apply force on both sides of the tunnel model 10 at the same time, so that the lifting driving force for the tunnel model 10 is more sufficient. In addition, the two lifting mechanisms 30 can perform not only synchronous lifting control but also asynchronous lifting control, which provides more options for the experimental process.

[0079] For example, in the normal experimental simulation process, the two lifting mechanisms 30 should be used for synchronous lifting control to achieve accurate simulation of general situations; in some special cases, the shield device and tunnel lining may be tilted or unevenly stressed due to construction errors. At this time, the asynchronous lifting control of the two lifting mechanisms 30 can realize the simulation of such situations, thereby providing the possibility for the study of rescue plans after construction errors.

[0080] Embodiment 4

[0081] The fourth embodiment of the tunnel excavation test device of the present invention is basically the same as the third embodiment. Figure 4-1 to Figure 4-3 As shown, the difference is that the tunnel excavation test device at this time also includes a model box 40, and the two opposite box walls of the model box 40 are respectively provided with a first transparent baffle 41 and a second transparent baffle 42, the first transparent baffle 41 is provided with a first through hole 411 passing through it, and the second transparent baffle 42 is provided with a second through hole 421 passing through it, and the diameters of the first through hole 411 and the second through hole 421 are both larger than the diameter of the central axis 21; the tunnel model 10 is arranged in the model box 40, and the tunnel model 10 is placed between the first transparent baffle 41 and the second transparent baffle 42; the two ends of the central axis 21 pass through the first through hole 411 and the second through hole 421 respectively to connect with the lifting mechanism 30.

[0082] When applying the tunnel excavation test device of the present invention, some larger boxes can be found to cooperate with the experiment. In this embodiment, a matching model box 40 is designed to maximize the experimental efficiency and optimize the experimental effect.

[0083] For example, after the model box 40 of this embodiment is added, the interior of the model box 40 can be used to fill the soil, and the diameters of the first through hole 411 and the second through hole 421 are larger than the diameter of the central axis 21, so it will not affect the lifting mechanism 30 to drive the tunnel model 10 to move up and down. In addition, during the experiment, the first transparent baffle 41 and the second transparent baffle 42 not only achieve the shielding of the soil, but also enable intuitive observation of the settlement changes of the tunnel model 10.

[0084] Embodiment 5

[0085] The fifth embodiment of the tunnel boring test device of the present invention is basically the same as the fourth embodiment. Figure 5-1 to Figure 5-12 As shown, the difference is that at this time, the tunnel wall of the tunnel model 10 is provided with a grouting hole 11 passing through it, and the two tunnel openings of the tunnel model 10 are respectively covered with a first flexible sealing plate 51 and a second flexible sealing plate 52 that can be retracted and deformed; the first flexible sealing plate 51 is arranged opposite to the first transparent baffle 41, and a first sealing sleeve 61 is arranged on the first flexible sealing plate 51; the second flexible sealing plate 52 is arranged opposite to the second transparent baffle 42, and a second sealing sleeve 62 is arranged on the second flexible sealing plate 52; a grouting joint 70 is provided on the first transparent baffle 41, and the grouting joint 70 passes through the first flexible sealing plate 51 and is connected to the grouting hole 11, and the grouting joint 70 and the first flexible sealing plate 51 are sealed; the two ends of the central axis 21 are respectively inserted into the first sealing sleeve 61 and the second sealing sleeve 62, and the central axis 21 and the first through hole 411 and the second through hole 421 are all movable elastically sealed. Connection.

[0086] like Figure 5-3 and Figure 5-5 As shown, in this embodiment, the above-mentioned first flexible sealing plate 51 can be made of flexible materials such as silicone, and the first flexible sealing plate 51 is in the shape of a circular plate, so as to fully cover the tunnel opening of the tunnel model 10; and there are two places where the first flexible sealing plate 51 needs to be sealed and connected, one is the periphery of the first flexible sealing plate 51 and the periphery of the tunnel opening of the tunnel model 10, and the other is the connection between the first flexible sealing plate 51 and the central axis 21.

[0087] For the sealing connection between the periphery of the first flexible sealing plate 51 and the periphery of the tunnel opening of the tunnel model 10, this embodiment has a plurality of through holes arranged on the periphery of the first flexible sealing plate 51, a plurality of threaded holes arranged on the periphery of the tunnel opening of the tunnel model 10, and four first arc-shaped positioning plates 81, each of which has a plurality of through holes with matching positions arranged on it.

[0088] Therefore, when performing the sealing installation of the periphery of the first flexible sealing plate 51, it should be ensured that the four first arc-shaped positioning plates 81 are all in contact with the outer surface of the first flexible sealing plate 51, and then bolts are used to pass through the corresponding holes of the first arc-shaped positioning plates 81 and the first flexible sealing plate 51 in turn, and threadedly connected with the threaded holes of the tunnel model 10. The first arc-shaped positioning plates 81, the first flexible sealing plate 51 and the tunnel model 10 can be bolted and fixed, thereby realizing the sealed connection between the periphery of the first flexible sealing plate 51 and the periphery of the tunnel entrance of the tunnel model 10.

[0089] The sealing connection between the first flexible sealing plate 51 and the central shaft 21 is mainly achieved by using the first sealing sleeve 61; Figure 5-3 , Figure 5-5 and Figure 5-8 As shown, in this embodiment, a first axial hole 511 is provided at the geometric center of the first flexible sealing plate 51, and a first sealing sleeve 61 is provided, including a first perforated inner plate 611, a first perforated outer plate 612 and a first sealing bearing 613. In the direction from the inside to the outside of the tunnel model 10, the first perforated inner plate 611, the first axial hole 511 and the first perforated outer plate 612 are sequentially arranged in a state of coaxial hole positions, the first perforated inner plate 611, the first axial hole 511 and the first perforated outer plate 612 are bolted and fixed, the first sealing bearing 613 is sealingly installed in the holes of the first perforated inner plate 611, the first axial hole 511 and the first perforated outer plate 612, and the central axis 21 is sealedly sleeved in the first sealing bearing 613, so that the sealing connection between the first flexible sealing plate 51 and the central axis 21 is realized.

[0090] Similar, such as Figure 5-4 and Figure 5-6 As shown, in this embodiment, the second flexible sealing plate 52 can be made of a flexible material such as silicone, and the second flexible sealing plate 52 is in the shape of a circular plate, so as to fully cover the other tunnel opening of the tunnel model 10; and there are two places where the second flexible sealing plate 52 needs to be sealed and connected, one is the periphery of the second flexible sealing plate 52 and the periphery of the tunnel opening of the tunnel model 10, and the other is the connection between the second flexible sealing plate 52 and the central axis 21.

[0091] For the sealing connection between the periphery of the second flexible sealing plate 52 and the periphery of the tunnel opening of the tunnel model 10, this embodiment has a plurality of through holes arranged on the periphery of the second flexible sealing plate 52, a plurality of threaded holes arranged on the periphery of another tunnel opening of the tunnel model 10, and four second arc-shaped positioning plates 82 arranged, each of which has a plurality of through holes with matching positions arranged on it.

[0092] Therefore, when performing the sealing installation of the periphery of the second flexible sealing plate 52, it should be ensured that the four second arc-shaped positioning plates 82 are all in contact with the outer surface of the second flexible sealing plate 52, and then bolts are used to pass through the corresponding holes of the second arc-shaped positioning plates 82 and the second flexible sealing plates 52 in sequence, and threadedly connected with the threaded holes of the tunnel model 10. The second arc-shaped positioning plates 82, the second flexible sealing plates 52 and the tunnel model 10 can be bolted and fixed, thereby realizing the sealed connection between the periphery of the second flexible sealing plate 52 and the periphery of another tunnel opening of the tunnel model 10.

[0093] The sealing connection between the second flexible sealing plate 52 and the central shaft 21 is mainly achieved by using the second sealing sleeve 62; Figure 5-4 , Figure 5-6 and Figure 5-9 In this embodiment, a second axial hole 521 is provided at the geometric center of the second flexible sealing plate 52, and a second sealing sleeve 62 is provided, including a second perforated inner plate 621, a second perforated outer plate 622, and a second sealing bearing 623. In the direction from the inside to the outside of the tunnel model 10, the second perforated inner plate 621, the second axial hole 521, and the second perforated outer plate 622 are sequentially arranged in a state of coaxial hole positions, and the second perforated inner plate 621, the second axial hole 521, and the second perforated outer plate 622 are bolted and fixed; the second sealing bearing 623 is sealingly installed in the hole positions of the second perforated inner plate 621, the second axial hole 521, and the second perforated outer plate 622, and the central axis 21 is sealedly sleeved in the second sealing bearing 623, so that the sealing connection between the second flexible sealing plate 52 and the central axis 21 is realized.

[0094] Further, such as Figure 5-1 , Figure 5-8 and Figure 5-10 As shown, in order to realize the movable elastic sealing connection between the central axis 21 and the first through hole 411, this embodiment is provided with a telescopically deformable third flexible sealing plate 53 in the first through hole 411, and a third sealing sleeve 63 is provided on the third flexible sealing plate 53, and the central axis 21 is sealedly sleeved in the third sealing sleeve 63; wherein, the third flexible sealing plate 53 of this embodiment can be made of flexible materials such as silicone, and the third flexible sealing plate 53 is set to be a circular plate shape, so as to fully cover the first through hole 411; in addition, there are two places where the third flexible sealing plate 53 needs to be sealed and connected, one is the periphery of the third flexible sealing plate 53 and the periphery of the first through hole 411, and the other is the connection between the third flexible sealing plate 53 and the central axis 21, and the specific implementation method is as follows.

[0095] For the sealing connection between the periphery of the third flexible sealing plate 53 and the periphery of the first through hole 411, as shown in FIG. Figure 5-8As shown, in this embodiment, the first through hole 411 is arranged as a stepped hole, and the tunnel excavation test device also includes a first pressure ring 91, so the periphery of the third flexible sealing plate 53 can be clamped between the step surface of the first through hole 411 and the first pressure ring 91, and because the first pressure ring 91 and the step surface of the first through hole 411 are bolted and fixed, a sealed connection and fixation between the two is also achieved.

[0096] For the sealing connection between the third flexible sealing plate 53 and the central shaft 21, as shown in FIG. Figure 5-1 , Figure 5-8 and Figure 5-10 As shown, in this embodiment, a third axial hole 531 is provided at the geometric center of the third flexible sealing plate 53, and a third sealing sleeve 63 is provided, including a third perforated inner plate 631, a third perforated outer plate 632 and a third sealing bearing 633. In the direction from the inside to the outside of the tunnel model 10, the third perforated inner plate 631, the third axial hole 531 and the third perforated outer plate 632 are sequentially arranged in a state where the holes are coaxial, and the third perforated inner plate 631, the third axial hole 531 and the third perforated outer plate 632 are fixed by bolts; the third sealing bearing 633 is sealingly installed in the holes of the third perforated inner plate 631, the third axial hole 531 and the third perforated outer plate 632, and the central axis 21 is sealedly sleeved in the third sealing bearing 633, so that the sealing connection between the third flexible sealing plate 53 and the central axis 21 is realized.

[0097] Similar, such as Figure 5-2 , Figure 5-9 and Figure 5-11 As shown, in order to realize the movable elastic sealing connection between the central axis 21 and the second through hole 421, this embodiment is provided with a telescopically deformable fourth flexible sealing plate 54 in the second through hole 421, and a fourth sealing sleeve 64 is provided on the fourth flexible sealing plate 54, and the central axis 21 is sealedly sleeved in the fourth sealing sleeve 64; wherein, the fourth flexible sealing plate 54 of this embodiment can be made of flexible materials such as silicone, and the fourth flexible sealing plate 54 is set to be a circular plate shape, so as to fully cover the second through hole 421; in addition, there are two places where the fourth flexible sealing plate 54 needs to be sealed and connected, one is the periphery of the fourth flexible sealing plate 54 and the periphery of the second through hole 421, and the other is the connection between the fourth flexible sealing plate 54 and the central axis 21, and the specific implementation method is as follows.

[0098] For the sealing connection between the periphery of the fourth flexible sealing plate 54 and the periphery of the second through hole 421, as shown in FIG. Figure 5-9As shown, in this embodiment, the second through hole 421 is arranged as a stepped hole, and the tunnel excavation test device also includes a second pressure ring 92, so that the periphery of the fourth flexible sealing plate 54 can be clamped between the step surface of the second through hole 421 and the second pressure ring 92, and because the second pressure ring 92 and the step surface of the second through hole 421 are bolted and fixed, a sealed connection and fixation between the two is also achieved.

[0099] For the sealing connection between the fourth flexible sealing plate 54 and the central shaft 21, as shown in FIG. Figure 5-2 , Figure 5-9 and Figure 5-11 As shown, in this embodiment, a fourth axial hole 541 is provided at the geometric center of the fourth flexible sealing plate 54, and a fourth sealing sleeve 64 is provided, including a fourth perforated inner plate 641, a fourth perforated outer plate 642 and a fourth sealing bearing 643. In the direction from the inside to the outside of the tunnel model 10, the fourth perforated inner plate 641, the fourth axial hole 541 and the fourth perforated outer plate 642 are sequentially arranged in a state where the holes are coaxial, and the fourth perforated inner plate 641, the fourth axial hole 541 and the fourth perforated outer plate 642 are fixed by bolts; the fourth sealing bearing 643 is sealingly installed in the holes of the fourth perforated inner plate 641, the fourth axial hole 541 and the fourth perforated outer plate 642, and the central axis 21 is sealedly sleeved in the fourth sealing bearing 643, so that the sealing connection between the fourth flexible sealing plate 54 and the central axis 21 is realized.

[0100] Therefore, after adopting the above-mentioned setting method, the inside of the tunnel model 10 can be isolated from the outside, so as to meet the relevant requirements of the later grouting operation. The specific operation method is as follows:

[0101] S1, first fill the box with soil until the soil reaches the lower part of the originally simulated tunnel, stop adding soil, place the tunnel model 10 on the added soil, use the lifting mechanism 30 to control the tunnel model 10 to descend, and after the connecting seat 31 is in contact with the pressure sensor 34, by monitoring the corresponding pressure information, adjust the pressure on the tunnel model 10 to be consistent with the soil force to be simulated, and then lead the relevant lines out of the box, and continue filling until the soil reaches the height designed in the test.

[0102] S2, the tunnel model 10 is controlled to gradually rise at a rate set in the experiment, so that the pressure on the tunnel model 10 is gradually unloaded until only the weight of the tunnel model 10 itself remains, thereby accurately simulating the unloading of soil excavation during tunnel excavation; in this process, the grouting joint 70 is simultaneously used to connect to the relevant grouting equipment so that the slurry is discharged through the grouting hole 11, according to the grouting pressure set in the experiment, to simulate the grouting condition behind the wall.

[0103] S3, change the grouting pressure and repeat steps S1 and S2.

[0104] S4, a displacement sensor and a slurry sensor can be set in the model box 40. By observing and recording the data of the displacement sensor and the slurry sensor, the floating of the tunnel model 10 under different grouting pressure conditions and the pressure of the slurry on the tunnel model 10 can be obtained to provide guidance for actual engineering.

[0105] For example, if the tunnel buoyancy is too large in an actual project, the tunnel will deviate from the expected construction track, the tunnel lining will collide with the soil or the shield machine and be damaged, etc. Therefore, after using this embodiment to simulate the above situation, it will be convenient to ensure the grouting effect in actual working conditions and control the grouting pressure as much as possible to reduce the tunnel buoyancy.

[0106] It should also be pointed out that if Figure 5-12 As shown, the central axis 21 of this embodiment is a screw rod, and the external thread of the central axis 21 is sleeved with a movable nut 23, and the two ends of the multiple support rods 22 are rotatably connected to the outer wall of the movable nut 23 and the inner wall of the tunnel model 10 respectively, and the central axis 21 is connected to an expansion motor 24, so when the expansion motor 24 controls the central axis 21 to rotate, the movement of the movable nut 23 will drive the multiple support rods 22 to expand or contract, thereby realizing the expansion and contraction control of the tunnel model 10, that is, the simulation of soil layer loss is realized by utilizing the change of the radial size of the tunnel model 10.

[0107] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A tunneling test device for simulating soil excavation and unloading, characterized in that: Including tunnel model, support mechanism and lifting mechanism; The support mechanism comprises a central axis and a support rod; the axial direction of the central axis is consistent with the axial direction of the tunnel model, and the central axis passes through the tunnel model; At least one of the support rods is connected between the outer wall of the central axis and the inner wall of the tunnel model; The lifting mechanism is placed outside the tunnel model, and includes a connecting seat, a base, and a hydraulic cylinder and a pressure sensor arranged on the base; the connecting seat is arranged above the base, and the connecting seat is connected to the central axis; the telescopic end of the hydraulic cylinder is connected to the connecting seat, and the hydraulic cylinder is used to drive the connecting seat to move up and down; the pressure sensor is arranged below the connecting seat, and the pressure sensor is used to abut against the bottom of the connecting seat for pressure monitoring; The tunnel excavation test device also includes a model box, wherein two opposite box walls of the model box are respectively provided with a first transparent baffle and a second transparent baffle, the first transparent baffle is provided with a first through hole passing through the first transparent baffle, and the second transparent baffle is provided with a second through hole passing through the second transparent baffle, and the diameters of the first through hole and the second through hole are both larger than the diameter of the central axis; The tunnel model is arranged in the model box, and the tunnel model is placed between the first transparent baffle and the second transparent baffle; The two ends of the central axis pass through the first through hole and the second through hole respectively to connect with the lifting mechanism; The tunnel wall of the tunnel model is provided with a grouting hole penetrating the tunnel, and the two tunnel openings of the tunnel model are respectively covered with a first flexible sealing plate and a second flexible sealing plate that can be retracted and deformed; the first flexible sealing plate is arranged opposite to the first transparent baffle, and a first sealing sleeve is arranged on the first flexible sealing plate; the second flexible sealing plate is arranged opposite to the second transparent baffle, and a second sealing sleeve is arranged on the second flexible sealing plate; A grouting joint is provided on the first transparent baffle plate, the grouting joint passes through the first flexible sealing plate and is connected to the grouting hole, and the grouting joint and the first flexible sealing plate are in a sealed connection; The two ends of the central shaft are respectively inserted into the first sealing sleeve and the second sealing sleeve, and the central shaft is movably elastically sealed to the first through hole and the second through hole; A first axial hole is provided at the geometric center of the first flexible sealing plate, and a second axial hole is provided at the geometric center of the second flexible sealing plate; The first sealing sleeve comprises a first inner plate with a hole, a first outer plate with a hole and a first sealing bearing. In the direction from the inside to the outside of the tunnel model, the first inner plate with a hole, the first axial hole and the first outer plate with a hole are sequentially arranged in a state where the holes are coaxial, and the first inner plate with a hole, the first axial hole and the first outer plate with a hole are connected and fixed by bolts; the first sealing bearing is sealingly installed in the holes of the first inner plate with a hole, the first axial hole and the first outer plate with a hole, and the central shaft is connected to the sealing sleeve in the first sealing bearing; The second sealed sleeve includes a second perforated inner plate, a second perforated outer plate and a second sealed bearing. In the direction from the inside to the outside of the tunnel model, the second perforated inner plate, the second axial hole and the second perforated outer plate are arranged in sequence in a coaxial state, and the second perforated inner plate, the second axial hole and the second perforated outer plate are fixed by bolts; the second sealed bearing is sealed and installed in the holes of the second perforated inner plate, the second axial hole and the second perforated outer plate, and the central shaft is connected to the sealing sleeve in the second sealed bearing.

2. The tunnel excavation test device according to claim 1, characterized in that: Both ends of the central axis extend out of the tunnel model, and both ends of the central axis are connected to the lifting mechanism.

3. The tunnel excavation test device according to claim 1, characterized in that: A third flexible sealing plate that can be flexibly deformed is disposed in the first through hole, a third sealing sleeve is disposed on the third flexible sealing plate, and the central shaft is connected to the sealing sleeve in the third sealing sleeve; A fourth flexible sealing plate that can be telescopically deformed is disposed in the second through hole, a fourth sealing sleeve is disposed on the fourth flexible sealing plate, and the central shaft is sealedly sleeved in the fourth sealing sleeve.

4. The tunnel excavation test device according to claim 3, characterized in that: The first through hole and the second through hole are step holes, and the tunnel excavation test device further includes a first pressure ring and a second pressure ring; The periphery of the third flexible sealing plate is clamped between the step surface of the first through hole and the first pressure ring, and the first pressure ring and the step surface of the first through hole are fixed by bolts; The periphery of the fourth flexible sealing plate is clamped between the step surface of the second through hole and the second pressure ring, and the second pressure ring and the step surface of the second through hole are fixedly connected by bolts.

5. The tunnel boring test device according to claim 4, characterized in that: A third axial hole is provided at the geometric center of the third flexible sealing plate, and a fourth axial hole is provided at the geometric center of the fourth flexible sealing plate; The third sealed sleeve comprises a third inner plate with holes, a third outer plate with holes and a third sealed bearing. In the direction from the inside to the outside of the tunnel model, the third inner plate with holes, the third axial hole and the third outer plate with holes are sequentially arranged in a state of coaxial hole positions, and the third inner plate with holes, the third axial hole and the third outer plate with holes are connected and fixed by bolts; the third sealed bearing is sealed and installed in the holes of the third inner plate with holes, the third axial hole and the third outer plate with holes, and the central shaft is connected to the sealing sleeve in the third sealed bearing; The fourth sealed sleeve includes a fourth inner plate with a hole, a fourth outer plate with a hole and a fourth sealed bearing. In the direction from the inside to the outside of the tunnel model, the fourth inner plate with a hole, the fourth axial hole and the fourth outer plate with a hole are arranged in sequence in a state of coaxial hole positions, and the fourth inner plate with a hole, the fourth axial hole and the fourth outer plate with a hole are fixed by bolts; the fourth sealed bearing is sealed and installed in the hole positions of the fourth inner plate with a hole, the fourth axial hole and the fourth outer plate with a hole, and the central shaft is connected to the sealing sleeve in the fourth sealed bearing.

6. The tunnel boring test device according to any one of claims 1 to 5, characterized in that: A plurality of support rods are arranged around the circumference of the central axis, and the plurality of support rods are connected between the outer wall of the central axis and the inner wall of the tunnel model.

7. The tunnel boring test device according to any one of claims 1 to 5, characterized in that: A guide flange and a vertically arranged column are provided on the top of the base, the pressure sensor is provided on the top of the column, a vertically arranged guide rod is inserted in the guide flange, and the guide rod is connected and fixed to the bottom of the connecting seat.

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