Large-diameter shield tunnel segment fine model manufacturing device and method

Abstract

The application discloses a kind of big diameter shield tunnel segment fine model manufacturing device and method, the manufacturing device includes A type component, B type component, C type component and D type component, the A type component, B type component, C type component and D type component are assembled to form ring cavity;Multiple combined components for simulating shield segment detail structure are arranged in the cavity, including rubber core mold, ring (longitudinal) boss component, ring (longitudinal) convex component, ring (longitudinal) concave component, concave (convex) groove component, ring (longitudinal) T component, sleeve.The manufacturing device is prepared based on 3D printing technology, overcome the low degree of detail component fine of the existing conventional manufacturing device It is short of the shortcoming, and size deviation caused by partition plate in integrated mold pouring can be effectively reduced, and the model produced accurately simulates the detail structure characteristics of prototype structure.

Description

A device and method for fabricating a detailed model of large-diameter shield tunnel segments Technical Field

[0001] This invention belongs to the field of civil engineering, and in particular, it relates to a device and method for making a refined model of a large-diameter shield tunnel segment lining structure. Background Technology

[0002] Indoor model testing is a crucial research method for studying the mechanical properties of tunnels, encompassing full-scale tests based on the load-structure method and scaled-down tests based on the stratum structure method. Full-scale tests primarily measure the mechanical properties of prototype unit components or single lining rings, but suffer from drawbacks such as small transverse and longitudinal dimensions, significant boundary effects, and the inability to conduct numerous repetitive tests. Scaled-down tests, on the other hand, can comprehensively consider the influence of strata and actual working conditions. By scaling down the scale with an appropriate similarity ratio, they can reflect the mechanical response of the tunnel structure under specific strata and working conditions, and allow for repeated comparative tests on single influencing factors.

[0003] In scaled-down test design based on the geological structure method, a large geometric similarity ratio is usually selected to meet basic conditions such as cross-sectional burial depth and geological boundaries. Therefore, the geometric dimensions of the tunnel model are generally small, and its detailed structure is often simplified or partially simulated, thus affecting the rationality of the tunnel model's mechanical analysis. Because large-diameter shield tunnels are characterized by numerous segmented sections and complex joint structures, their detailed structure has a significant impact on structural performance. Therefore, in scaled-down tests, effectively simulating the detailed structure of the segment lining of large-diameter shield tunnels becomes a key issue determining the rationality and accuracy of the test.

[0004] The existing scaled-down models of shield tunnels mainly adopt an integrated casting method (CN 206748721 U, CN109741675A, CN 107945646B, CN 114833937A, CN 215150318U). The fabrication device is mainly composed of an inner template, an outer template, an upper cover plate, and a lower cover plate. By adding partition plates, single-ring segments are divided into sections, and circumferential bolts are inserted to achieve circumferential connections between segments. Some devices also simulate longitudinal connections between segment rings by setting longitudinal partition plates and longitudinal bolts.

[0005] However, the above-mentioned fabrication device has the following shortcomings: 1) The simulation of the longitudinal and circumferential joint structure of the above-mentioned fabrication device is only reflected in the bolt components, and does not involve the detailed simulation of the complete joint structure such as waterproof sealing caulking and force transmission gasket caulking; 2) Although the partition plate in the above-mentioned fabrication device plays the role of segmenting the tunnel segments, the model size deviation caused by the partition plate is not negligible; 3) The above-mentioned fabrication device is mainly suitable for conventional subway shield tunnels, which have small tunnel diameters and simple joint structures. Compared with large-diameter shield tunnels containing special components such as T-shaped components, tongue and groove joints, and shear pins, it will no longer be applicable; 4) The above-mentioned fabrication device generally adopts the form of mechanical processing, and selects wood or steel as the mold making materials, which has limited processing accuracy.

[0006] To address the technical challenges of preparing a refined model of the segment lining structure of a large-diameter shield tunnel, and to ensure that the segment lining model possesses the same structural features as the prototype tunnel, it is urgently necessary to design a low-cost, easy-to-manufacture, and reusable model-making device and corresponding manufacturing method for scaled-down model testing research. This is of great significance for research on related topics concerning large-diameter shield tunnels. Summary of the Invention

[0007] To overcome the shortcomings of the existing technology, the present invention provides a device and method for making a refined model of a large-diameter shield tunnel segment lining structure.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A device for fabricating a detailed model of a large-diameter shield tunnel segment is characterized by comprising an A-type component 1, a B-type component 2, a C-type component 3, and a D-type component 4, which are assembled to form a mold cavity for a scaled-down model of the tunnel segment lining. The mold cavity contains multiple composite components for simulating the detailed structure of the shield tunnel segment, including a rubber core mold 5, a circumferential boss component 23, a longitudinal boss component 7, a circumferential convex component 8, a longitudinal convex component 9, a circumferential concave component 10, a longitudinal concave component 11, a groove component 24, a convex groove component 25, a circumferential T-shaped component 13, a longitudinal T-shaped component 14, and a sleeve 15.

[0010] Furthermore, the assembly method of the mold cavity is as follows: the bottom surfaces of the A-type component 1 and the B-type component 2 are flush and concentrically arranged on the top surface of the D-type component 4, and the C-type component 3 is arranged on the top surfaces of the A-type component 1 and the B-type component 2; specifically, the A-type component 1, the B-type component 2, the C-type component 3 and the D-type component 4 are all provided with connecting holes 18, and fixing bolts 19 are passed through the connecting holes 18 to fix the upper and lower ends of the A-type component to the C-type component and the D-type component respectively, while fixing the upper and lower ends of the B-type component to the C-type component and the D-type component respectively.

[0011] Furthermore, the bottom of the C-shaped component 3 and the top of the D-shaped component 4 are provided with corresponding grooves 20. A rubber core mold 5 is provided in the molding cavity. The top and bottom of the rubber core mold 5 are fixed in the grooves 20 of the C-shaped component 3 and the D-shaped component 4, respectively. The rubber core mold 5 is a hollow structure with a special rubber material on the outer layer and gas filling inside. An air valve 6 is provided on the top of the rubber core mold 5, and an air pressure gauge is provided on the air valve 6.

[0012] Furthermore, the bottom surface of the C-type component 3 and the top surface of the D-type component 4 are provided with a plurality of circumferential bosses 23, and the molding cavity is provided with a plurality of longitudinal bosses 7. The top and bottom of the longitudinal bosses 7 are respectively fixed in the grooves 20 of the C-type component 3 and the D-type component 4. The circumferential bosses 23 are rings with a trapezoidal cross-section, and the direction of the rings is parallel to that of components C and D. The longitudinal bosses 7 are prisms with a trapezoidal cross-section, and the direction is longitudinal, consistent with the direction of the rubber core mold.

[0013] Furthermore, the outer surface of the A-type component 1 is provided with a plurality of circumferential convex members 8 and longitudinal convex members 9, the outer surface of the D-type component 4 is provided with a plurality of longitudinal convex members 9, the inner surface of the A-type component 1 is provided with a plurality of circumferential concave members 10 and longitudinal concave members 11, and the inner surface of the D-type component 4 is provided with a plurality of longitudinal concave members 11. The circumferential convex members and the circumferential concave members are paired and combined, and the longitudinal convex members and the longitudinal concave members are paired and combined, and their positions correspond one-to-one.

[0014] Furthermore, the circumferential convex members 8 are located on both sides of the rubber core mold 5, and each rubber core mold 5 includes n circumferential convex members 8 on both sides, distributed as follows:

[0015] 1) When n is odd, there are two distribution patterns:

[0016] a) n-1 / 2 on one side and n+1 / 2 on the other side, arranged in an alternating pattern on both sides; b) n on one side and zero on the other side, arranged in an equidistant pattern on one side.

[0017] 2) When n is even, there are two distribution patterns:

[0018] a) n / 2 on one side and n / 2 on the other side, arranged in an alternating pattern on both sides; b) n on one side and zero on the other side, arranged in an equidistant pattern on one side.

[0019] Furthermore, the longitudinal convex members 9 are distributed in a ring around the A-type member, with a quantity of m (m is an even number), and the distribution is as follows:

[0020] 1) Single group: Each longitudinal convex component 9 is located at the circumferential m equally divided points;

[0021] 2) Two in a group: Every two longitudinal convex components 9 form a group and maintain a certain interval. Each group of longitudinal convex components 9 is set at the circumferential m / 2 division point. The center of the midpoint of the arc between the two longitudinal convex components 9 coincides with the center of the m / 2 division point.

[0022] Furthermore, the bottom surface of the C-shaped component 3 is provided with a plurality of protruding groove members 25, and the top surface of the D-shaped component 4 is provided with a groove member 24.

[0023] Furthermore, both the groove member 25 and the recess member 24 are frustum-shaped lofting members. The number of groove members 25 and recess members 24 is related to the number of longitudinal boss members 9, specifically as follows:

[0024] 1) The longitudinal convex components 9 are distributed in a single group: the number of convex groove components 25 and groove components 24 is the same as that of the longitudinal convex components 9;

[0025] 2) The longitudinal convex components 9 are distributed in pairs: the number of convex groove components 25 and groove components 24 is half the number of longitudinal convex components 9.

[0026] Furthermore, the grooved member 25 and the recessed member 24 are circumferentially equidistantly distributed on the C-shaped member 3 and the D-shaped member 4, respectively, and their distribution positions are related to the longitudinal convex member 9, specifically as follows:

[0027] 1) The longitudinal convex members 9 are distributed in a single group: the centers of the convex groove members 25 and the concave groove members 24 are consistent with the circumferential division centers of the longitudinal convex members 9;

[0028] 2) The longitudinal convex components 9 are distributed in pairs: the center of the convex groove component 25 and the groove component 24 coincides with the center of the midpoint of the arc line separating the two longitudinal convex components 9.

[0029] Furthermore, the C-type component 3, D-type component 4, rubber core mold 5, circumferential boss component 23, longitudinal boss component 7, circumferential convex component 8, longitudinal convex component 9, circumferential concave component 10, and longitudinal concave component 11 are all provided with channels 21, and the channels in the circumferential concave component 10 and the longitudinal concave component 11 are threaded inside.

[0030] Furthermore, the longitudinal T-shaped member 14 is disposed inside the longitudinal convex member 9 and the longitudinal concave member 11, and the circumferential T-shaped member 13 is disposed inside the circumferential convex member 8 and the circumferential concave member 10, and passes through the rubber core mold 5; both the circumferential T-shaped member 13 and the longitudinal T-shaped member 14 are provided with threads, are positioned by the channel, and are fixed by the internal threads of the longitudinal concave member 10 and the longitudinal concave member 11. The ends of the circumferential T-shaped member 13 and the longitudinal T-shaped member 14 may be provided with sleeves 15, and the sleeves are provided with corresponding threads.

[0031] Furthermore, the fabrication device is prepared by 3D printing, and the similarity ratio and 3D printing material selection meet the following principles: 1) When the similarity ratio is 1 / 5 to 1 / 25, ordinary resin or tough resin with a printing tolerance of ±0.1 to 0.2 mm is selected; 2) When the similarity ratio is 1 / 25 to 1 / 50, red wax, aluminum alloy or stainless steel with a printing tolerance of ±0.01 to 0.05 mm is selected.

[0032] The present invention also provides a method for fabricating a detailed scale model of a large-diameter shield tunnel segment using the aforementioned fabrication device, comprising the following steps:

[0033] 1) Apply release agent evenly to the surface of the manufacturing device, assemble type A, type B, type C and type D components, and install rubber core mold 5, longitudinal boss component 23, steel cage 26 and circumferential T-shaped component 13 and longitudinal T-shaped component 14. Screw sleeves 15 onto the ends of circumferential T-shaped component 13 and longitudinal T-shaped component 14.

[0034] 2) Open the truncated cone cap 22 on the C-type component 3 to expose the grouting port, inject grout of a material similar to the pipe segment into the grouting port, place the manufacturing device on the vibrating table for vibration until the grout is level or overflows from the grouting port;

[0035] 3) Adjust the air valve 6 of the rubber core mold to reduce the air pressure inside the rubber core mold 5, so as to reduce the thickness of the rubber core mold 5 to the thinnest thickness. At this time, observe whether the grout level at the injection port is lower than the top surface of the C-type component 3. If it is higher, cover it with the frustum cap 22; if it is lower or equal to, continue to add grout and make the grout level higher than the top surface of the C-type component 3, and then cover it with the frustum cap 22.

[0036] 4) Place the fabrication device in a constant temperature and humidity environment for curing. After the tunnel model reaches the demolding strength, first remove the pre-embedded circumferential T-shaped component 13 and longitudinal T-shaped component 14, and then remove the C-shaped component 3, rubber core mold 5, longitudinal boss component 23, B-shaped component 2, D-shaped component 4 and A-shaped component 1 in sequence to finally obtain the tunnel model.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The large-diameter shield tunnel lining structure model obtained by the device of the present invention has the same circumferential (longitudinal) handholes, circumferential (longitudinal) T-shaped components, circumferential (longitudinal) sealing joints and concave and convex tenons as the prototype tunnel, which can effectively simulate the key detailed structures that affect the mechanical performance of the tunnel structure.

[0039] (2) The rubber core mold described in the present invention minimizes the dimensional deviation caused by the segment plates in the existing integrated mold casting process.

[0040] (3) The device of the present invention has high mold manufacturing precision, small tunnel model size and assembly error, and high degree of restoration of detailed structure. Attached Figure Description

[0041] Figure 1 is a schematic diagram of the manufacturing apparatus of an example of the present invention.

[0042] Figure 2 is a schematic diagram of a fabrication device with a steel cage installed according to an example of the present invention.

[0043] Figure 3 is a schematic diagram of the A-type component of the design example of the present invention.

[0044] Figure 4 is a schematic diagram of the B-type component of the design example of the present invention.

[0045] Figure 5 is a schematic diagram of the C-type component of the design example of the present invention.

[0046] Figure 6 is a bottom view of the C-type component of the design example of the present invention.

[0047] Figure 7 is a schematic diagram of the D-type component of the design example of the present invention.

[0048] Figure 8 is a front view of the D-type component of the design example of the present invention.

[0049] Figure 9 is a bottom view of the D-type component of the design example of the present invention.

[0050] Figure 10 is a schematic diagram of the rubber core mold of the present invention.

[0051] Figure 11 is a schematic diagram of the circumferential (longitudinal) convex component of the present invention.

[0052] Figure 12 is a schematic diagram of the circumferential (longitudinal) T-shaped component of the present invention.

[0053] Figure 13 is a schematic diagram of the sleeve in the design example of the present invention.

[0054] Figure 14 is a schematic diagram of the groove component of the present invention.

[0055] Reference numerals: Type A component 1, Type B component 2, Type C component 3, Type D component 4, Rubber core mold 5, Air valve 6, Longitudinal boss component 7, Circumferential convex component 8, Longitudinal convex component 9, Circumferential concave component 10, Longitudinal concave component 11, Semicircular flange 12, Circumferential T-shaped component 13, Longitudinal T-shaped component 14, Sleeve 15, Flange plate 16, Stiffening rib 17, Connecting hole 18, Fixing bolt 19, Groove 20, Channel 21, Frustum cap 22, Circumferential boss component 23, Groove component 24, Spiral groove component 25, Reinforcing cage 26. Detailed Implementation

[0056] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0057] As shown in Figures 1-12, the present invention provides a device for fabricating a detailed model of a large-diameter shield tunnel segment, comprising a type A component 1, a type B component 2, a type C component 3, and a type D component 4. The type A component, type B component, type C component, and type D component are assembled to form a molding cavity for a scaled-down model of the tunnel segment lining. The molding cavity is provided with multiple combined components for simulating the detailed structure of the shield tunnel segment, including a rubber core mold, a circumferential (longitudinal) boss component, a circumferential (longitudinal) convex component, a circumferential (longitudinal) concave component, a concave (convex) groove component, a circumferential (longitudinal) T-shaped component, and a sleeve.

[0058] As shown in Figure 1, the bottom surfaces of the type A and type B components are flush and concentrically disposed on the top surface of the type D component, and the type C component is disposed on the top surfaces of the type A and type B components. Specifically, the inner sides of the upper and lower ends of the type A component, the inner sides of the type C component, and the inner sides of the type D component are all provided with corresponding semi-circular wing plates 12. Each semi-circular wing plate 12 is provided with a connecting hole 18, and fixing bolts 19 are passed through the connecting holes 18 to fix the upper and lower ends of the type A component to the type C component and the type D component, respectively. The upper and lower flange plates 16 of the type B component and the type D component are also provided with connecting holes 18, and fixing bolts 19 are used to fix the upper and lower ends of the type B component to the type C component and the type D component, respectively. Further, in this embodiment, the type B component adopts a multi-segment structure, and can be connected and fixed by providing connecting holes 18 at the joints and using fixing bolts 19.

[0059] A rubber core mold 5 is provided inside the molding cavity. The top and bottom of the rubber core mold are fixed in the slots 20 of the C-type component and D-type component, respectively. The rubber core mold is a hollow structure with a special rubber material on the outer layer. The thickness of the special rubber material can be selected from 0.01 to 0.1 mm according to the precision requirements of the segment manufacturing. The interior is filled with gas. The function of the rubber core mold is to realize the segment division. An air valve 6 is provided on the top of the rubber core mold 5. The air valve is equipped with an air pressure gauge (not shown in the figure). Before the model is poured, the rubber core mold is filled with gas to meet the assembly requirements. During the model pouring process, the air valve is adjusted and the air pressure inside the rubber core mold is gradually reduced according to the air pressure gauge reading until the minimum air pressure is reached. At this time, the rubber core mold is at its thinnest thickness, so as to minimize the dimensional deviation caused by the segment plate during the integrated mold pouring.

[0060] Both the bottom surface of the C-type component and the top surface of the D-type component are provided with circumferential boss members 23, and the mold cavity is provided with longitudinal boss members 7. The top and bottom of the longitudinal boss members 7 are respectively fixed in the grooves 20 of the C-type component and the D-type component. The function of the circumferential (longitudinal) boss members is to form a circumferential (longitudinal) waterproof sealing joint structure for the pipe segment.

[0061] The outer surface of the type A component is provided with a circumferential (longitudinal) convex member, the outer surface of the type D component is provided with a longitudinal convex member 9, the inner surface of the type A component is provided with a circumferential (longitudinal) concave member, and the inner surface of the type D component is provided with a longitudinal concave member 11. The function of the circumferential (longitudinal) convex member is to form a circumferential (longitudinal) hand hole structure for the segment. The circumferential convex member and the circumferential concave member are paired and combined, and the longitudinal convex member and the longitudinal concave member are paired and combined, and their positions correspond one-to-one.

[0062] The circumferential convex components 8 are located on both sides of the rubber core mold 5. Each rubber core mold includes n circumferential convex components on both sides, distributed as follows:

[0063] 1) When n is odd, there are two distribution patterns:

[0064] a) n-1 / 2 on one side and n+1 / 2 on the other side, arranged in an alternating pattern on both sides; b) n on one side and zero on the other side, arranged in an equidistant pattern on one side.

[0065] 2) When n is even, there are two distribution patterns:

[0066] a) n / 2 on one side and n / 2 on the other side, arranged in an alternating pattern on both sides; b) n on one side and zero on the other side, arranged in an equidistant pattern on one side.

[0067] The longitudinal convex members are distributed in a ring around the A-type member, with a quantity of m (m is an even number), and the distribution is as follows:

[0068] 1) Single group: Each longitudinal convex component is located at a circumferential m-division point;

[0069] 2) Two in a group: Each pair of longitudinal convex components forms a group and maintains a certain interval. Each group of longitudinal convex components is set at the m / 2 equidistant points in the circumferential direction. The center of the midpoint of the arc between the two longitudinal convex components coincides with the center of the m / 2 equidistant points.

[0070] The bottom surface of the C-type component is provided with a convex groove member 25, and the top surface of the D-type component is provided with a groove member 24; the function of the convex (concave) groove member is to form a tenon-and-groove structure for the tube segment.

[0071] Both the convex groove member 25 and the concave groove member 24 are frustum-shaped lofting members. The number of convex (concave) groove members is related to the number of longitudinal convex members 9, specifically as follows:

[0072] 1) The longitudinal convex components 9 are distributed in a single group: the number of convex (concave) groove components is the same as that of the longitudinal convex components;

[0073] 2) The longitudinal convex components 9 are distributed in pairs: the number of convex (concave) groove components is half the number of longitudinal convex components.

[0074] The protruding groove member 25 and the recessed groove member 24 are circumferentially equidistantly distributed on the C-shaped member and the D-shaped member, respectively. Their distribution positions are related to the longitudinal convex member 9, specifically as follows:

[0075] 1) The longitudinal convex components 9 are distributed in a single group: the center of the convex (concave) groove component is consistent with the circumferential division center of the longitudinal convex component 9;

[0076] 2) The longitudinal convex components 9 are distributed in pairs: the center of the convex (concave) groove component coincides with the center of the midpoint of the arc line separating the two longitudinal convex components 9;

[0077] The C-type component, D-type component, rubber core mold, circumferential (longitudinal) boss component, circumferential (longitudinal) convex component and circumferential (longitudinal) concave component are all provided with channels 21; the channel 21 in the circumferential (longitudinal) concave component has a thread inside, and the dimensions of the channel 21 and the thread are consistent with the dimensions of the circumferential (longitudinal) T-type component.

[0078] The longitudinal T-shaped member 14 is disposed inside the longitudinal convex member 9 and the longitudinal concave member 11; the circumferential T-shaped member 13 is disposed inside the circumferential convex member 8 and the circumferential concave member 10, and passes through the rubber core mold 5; each longitudinal (circumferential) T-shaped member is provided with threads, positioned by a channel, and fixed by the internal threads of the longitudinal (circumferential) concave member; a sleeve 15 may be provided at the end of the longitudinal (circumferential) T-shaped member, the sleeve is provided with threads, and the internal thread size of the sleeve is consistent with the thread size at the end of the circumferential (longitudinal) T-shaped member.

[0079] As an example, and not a limitation, the fabrication device is manufactured using 3D printing to ensure high precision of the mold. The similarity ratio and 3D printing material selection meet the following principles: 1) When the similarity ratio is 1 / 5 to 1 / 20, ordinary resin or tough resin with a printing tolerance of ±0.1 to 0.2 mm is selected; 2) When the similarity ratio is 1 / 20 to 1 / 50, red wax, aluminum alloy, or stainless steel with a printing tolerance of ±0.02 to 0.05 mm is selected. Since the size of the similarity ratio determines the size of the fabrication device, it is necessary to select appropriate 3D printing materials according to the similarity ratio to control the 3D printing cost of the fabrication device while meeting the model fabrication precision requirements. That is, when the similarity ratio is large (1 / 5 to 1 / 20), it is recommended to choose ordinary resin or tough resin with medium precision and low cost; when the similarity ratio is small (1 / 20 to 1 / 50), it is recommended to choose red wax, aluminum alloy, or stainless steel with higher precision and higher finished product quality.

[0080] The method for creating a detailed model of large-diameter shield tunnel segments described in this application includes the following steps:

[0081] 1) Apply release agent evenly to the surface of the manufacturing device, assemble type A, type B, type C and type D components, and install rubber core mold, longitudinal boss component, steel cage and circumferential (longitudinal) T-shaped component rod. Rubber sleeves need to be screwed on the ends of the circumferential (longitudinal) T-shaped component.

[0082] 2) Open the truncated cone cap 22 on the C-type component to expose the grouting port, inject grout of a material similar to that of the pipe segment into the grouting port, place the manufacturing device on the vibrating table for vibration until the grout is level or overflows from the grouting port;

[0083] 3) Adjust the air valve of the rubber core mold to reduce the air pressure inside the rubber core mold, so as to reduce the thickness of the rubber core mold to the thinnest thickness. At this time, observe whether the grout level at the injection port is lower than the top surface of the C-type component. If it is higher, cover it with the truncated cone cap; if it is lower or equal to, continue to add grout and make the grout level higher than the top surface of the C-type component, and then cover it with the truncated cone cap.

[0084] 4) Place the fabrication device in a constant temperature and humidity environment for curing. After the tunnel model reaches the demolding strength, first remove the embedded ring (longitudinal) T-shaped component, then remove the C-shaped component, rubber core mold, longitudinal boss component, B-shaped component, D-shaped component and A-shaped component in sequence, and finally obtain the tunnel model.

[0085] The tunnel model obtained using this device has small size and assembly errors, and a high degree of detail in its structural reproduction.

[0086] Example

[0087] The similarity ratio of the experiment in this embodiment is 1 / 20. Based on the similarity ratio and the principle of selecting 3D printing materials, the fabrication device is made using ordinary resin material, with a manufacturing tolerance of ±0.1mm. The large-diameter tunnel model (i.e., the tunnel segment after casting and demolding) to be fabricated in this embodiment has an outer diameter of 750mm, an inner diameter of 685mm, a thickness of 65mm, and a width of 200mm, and is cast using micro-particle concrete or gypsum material. The segment lining ring (i.e., the annular tunnel segment obtained after demolding) consists of one capping segment, two adjacent segments, and seven standard segments. The capping segment corresponds to a central angle of 11.75°, the adjacent segments to a central angle of 39.20°, and the remaining standard segments to a central angle of 38.55°. Ten longitudinal joints are formed by the circumferential connection of the segments. Three circumferential T-shaped components are set at each rubber core mold (longitudinal joint), for a total of thirty circumferential T-shaped components. The longitudinal rings of the tube segment are connected by twenty-eight sets of diagonal bolts, with two bolts in each set. Therefore, fifty-six longitudinal T-shaped members are provided on the longitudinal convex members of both type A and type D components to simulate the pre-drilled holes for the diagonal bolts. Each ring surface of the tube segment has twenty-eight distributed tenons or mortises. In this embodiment, the upper end face is a tenon and the lower end face is a mortise.

[0088] Mold making:

[0089] Before casting the model, a water-based release agent is applied to the fabrication device, including the outer surface of the A-type component, the inner surface of the B-type component, the lower surface of the C-type component, and the upper surface of the D-type component. After the release agent is applied, the D-type component is placed on a flat workbench. After placement, fixing bolts are used to connect the A-type and D-type components by passing them through the connection holes of the inner semi-circular flanges 12. The A-type and D-type components are then connected as a whole. The reinforcing cage 26 is placed on the D-type component, and its position is adjusted to ensure that the thickness of the concrete cover on all four sides (inner, outer, left, and right) is consistent with the experimental design. A longitudinal T-shaped component 14 is screwed into the D-type component from the inside through the longitudinal concave component 11. The longitudinal T-shaped component 14 passes through the longitudinal convex component 9 and the D-type component in sequence and extends into the casting cavity. A sleeve 15 is installed at the end of the fixed longitudinal T-shaped component.

[0090] In this embodiment, a rubber core mold with a single-sided rubber thickness of 0.05 mm is selected. Gas is filled into the rubber core mold to make the total thickness of the rubber core mold 0.2 mm, i.e., the total rubber thickness 0.1 mm, resulting in an expansion of 0.1 mm and a corresponding gas pressure of 200 kPa. Subsequently, the rubber core mold 5 and the longitudinal boss component 7 are fixed using the preset groove 20 on the D-type component. The circumferential T-type component 13 is screwed into the A-type component from the inside through the circumferential concave component 10. The circumferential T-type component 13 passes sequentially through the circumferential convex component 8 and the rubber core mold 5 into the casting cavity. A sleeve 15 is installed at the end of the fixed circumferential T-type component 13. After the circumferential T-type component 13 is installed, the B-type component is placed on the D-type component. Fixing bolts 19 are used to connect the B-type component and the D-type component through the preset connection holes 18. Then, fixing bolts 19 are used to connect multiple B-type component segments through the preset connection holes 18 of the B-type component. After the internal ring (longitudinal) T-shaped components are assembled, the C-shaped component is placed on top of the A-shaped and B-shaped components and connected by fixing bolts 19. The longitudinal T-shaped component 14 is inserted through the pre-drilled hole 21 in the C-shaped component into the casting cavity, passes through the longitudinal convex component 9, and is fixed by the longitudinal concave component 11. At this point, the fabrication device is assembled. For each assembly process described above, the assembly error must be adjusted before tightening the fixing bolts and proceeding to the next assembly step. In this embodiment, the C-shaped component and its bottom circumferential boss component 23 are a single unit, the D-shaped component and its top circumferential boss component 23 are a single unit, and the longitudinal boss component 7 and the rubber core mold 5 are a single unit. The circumferential boss component 23 is a trapezoidal ring with its direction parallel to components C and D. The longitudinal boss component 7 is a trapezoidal prism with its direction longitudinal, consistent with the direction of the rubber core mold.

[0091] Pouring:

[0092] Place the fabrication device on a vibrating table. Pour the micro-particle concrete mixture into the casting cavity through the grouting holes, completing the process in three stages. Each addition should fill one-third of the cavity volume. After each addition, vibrate the device on the table for 30-60 seconds to ensure uniform mixing before proceeding to the next addition. After the third addition, the grout level should be sufficient to rise above the grouting holes of the C-shaped component. Then, return the fabrication device to the worktable and adjust the air valve of the rubber core mold, gradually reducing the internal air pressure until it reaches 0 kPa, thus reducing the total thickness of the rubber core mold to 0.1 mm. Observe whether the grout level at the grouting port is lower than the bottom surface of the C-shaped component. If it is higher, cover it with the truncated cone cap 22; if it is lower or equal, continue adding grout until the level is higher than the bottom surface of the C-shaped component, then cover it with the truncated cone cap. The model casting is now complete.

[0093] Demolding:

[0094] The fabrication device is placed in a constant temperature and humidity environment for curing. After the tunnel model reaches the demolding strength, the embedded ring (longitudinal) T-shaped components are removed in the order of C-type components to D-type components. Then, the C-type components, rubber core mold 5, longitudinal boss components 7, B-type components, D-type components and A-type components are removed in sequence. Finally, the tunnel model is demolded.

[0095] In this embodiment, the T-shaped component and the sleeve are connected by a threaded connection. Disassembly simply requires unscrewing the T-shaped component in the reverse direction. After demolding, the end sleeve remains inside the tunnel segment to simulate a diagonal bolt anchoring device.

[0096] The technical solutions in the embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above. The above embodiments are merely exemplary and not restrictive. Those skilled in the art can make many modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of the prior art should be within the scope of protection defined by the claims.

Claims

1. A device for fabricating a detailed model of large-diameter shield tunnel segments, characterized in that, The model includes Type A, Type B, Type C, and Type D components. Type A (1), Type B (2), Type C (3), and Type D (4) are assembled to form the molding cavity of a scaled-down model of the tunnel lining. The molding cavity contains multiple composite components for simulating the detailed structure of the tunnel lining segments, including a rubber core mold (5), a circumferential boss component (23), a longitudinal boss component (7), a circumferential convex component (8), a longitudinal convex component (9), a circumferential concave component (10), a longitudinal concave component (11), a groove component (24), a slotted component (25), a circumferential T-shaped component (13), a longitudinal T-shaped component (14), and a sleeve (15). The bottom of the C-type component (3) and the top of the D-type component (4) are provided with corresponding grooves (20). A rubber core mold (5) is provided in the molding cavity. The top and bottom of the rubber core mold (5) are fixed in the grooves (20) of the C-type component (3) and the D-type component (4) respectively. The rubber core mold (5) is a hollow structure with a special rubber material on the outer layer and filled with gas inside. An air valve (6) is provided on the top of the rubber core mold (5), and an air pressure gauge is provided on the air valve (6). Several circumferential boss components (23) are provided on the bottom surface of the C-type component (3) and the top surface of the D-type component (4). Several longitudinal boss components (7) are provided in the molding cavity. The top and bottom are respectively fixed in the grooves (20) of the C-type component (3) and the D-type component (4); the convex groove component (25) is set on the bottom surface of the C-type component (3), and the recessed groove component (24) is set on the top surface of the D-type component (4); the convex groove component (25) and the recessed groove component (24) are both frustum-shaped lofting components, and the number of convex groove components (25) and recessed groove components (24) is related to the number of longitudinal convex components (9), specifically: 1) the longitudinal convex components (9) are distributed in a single group: the number of convex groove components (25) and recessed groove components (24) is the same as that of the longitudinal convex components (9); 2) the longitudinal convex components (9) are distributed in pairs: the convex groove component (25) The number of groove components (24) is half the number of longitudinal convex components (9); the groove components (25) and the groove components (24) are circumferentially equidistantly distributed on the C-type component (3) and the D-type component (4), respectively, and their distribution positions are related to the longitudinal convex components (9). Specifically, the longitudinal convex components (9) are distributed in a single group: the center of the groove component (25) and the groove component (24) is consistent with the circumferential equidistant center of the longitudinal convex components (9); 2) the longitudinal convex components (9) are distributed in pairs: the center of the groove component (25) and the groove component (24) is consistent with the center of the midpoint of the arc line between the two longitudinal convex components (9).The C-shaped component (3), D-shaped component (4), rubber core mold (5), circumferential boss component (23), longitudinal boss component (7), circumferential convex component (8), longitudinal convex component (9), circumferential concave component (10), and longitudinal concave component (11) are all provided with channels. The channels in the circumferential concave component (10) and longitudinal concave component (11) are threaded. The longitudinal T-shaped component (14) is located inside the longitudinal convex component (9) and longitudinal concave component (11). The circumferential T-shaped component (13) is located inside the circumferential convex component (8) and circumferential concave component (10) and passes through the rubber core mold (5). The circumferential T-shaped component (13) and longitudinal T-shaped component (14) are both threaded, positioned through the channels, and fixed by the internal threads of the circumferential concave component (10) and longitudinal concave component (11).

2. The device for fabricating a detailed model of large-diameter shield tunnel segments according to claim 1, characterized in that, The bottom surfaces of the type A component (1) and type B component (2) are flush and concentrically disposed on the top surface of the type D component (4). The type C component is disposed on the top surfaces of type A component (1) and type B component (2). The type A component (1), type B component (2), type C component (3) and type D component (4) are all provided with connecting holes (18). By passing fixing bolts (19) through the connecting holes (18), the upper and lower ends of type A component are fixed to type C component and type D component respectively, and the upper and lower ends of type B component are fixed to type C component and type D component respectively.

3. The device for fabricating a detailed model of large-diameter shield tunnel segments according to claim 1, characterized in that, The outer surface of the A-type component (1) is provided with several circumferential convex members (8) and longitudinal convex members (9). The outer surface of the D-type component (4) is provided with several longitudinal convex members (9). The inner surface of the A-type component (1) is provided with several circumferential concave members (10) and longitudinal concave members (11). The inner surface of the D-type component (4) is provided with several longitudinal concave members (11). The circumferential convex members and circumferential concave members are paired and combined, and the longitudinal convex members and longitudinal concave members are paired and combined, and their positions correspond one-to-one.

4. The device for fabricating a detailed model of large-diameter shield tunnel segments according to claim 3, characterized in that, The circumferential convex components (8) are located on both sides of the rubber core mold (5). Each rubber core mold (5) includes n circumferential convex components (8) on both sides, and the distribution is as follows: 1) When n is odd, there are two distribution patterns: a) n-1 / 2 on one side and n+1 / 2 on the other side, and the longitudinal arrangement is staggered on both sides; b) n on one side and zero on the other side, and the longitudinal arrangement is equidistant on one side; 2) When n is even, there are two distribution patterns: a) n / 2 on one side and n / 2 on the other side, and the longitudinal arrangement is staggered on both sides; b) n on one side and zero on the other side, and the longitudinal arrangement is equidistant on one side.

5. The device for fabricating a detailed model of large-diameter shield tunnel segments according to claim 3, characterized in that, The longitudinal convex components (9) are distributed in a ring on the A-type component, with a quantity of m (m is an even number). The distribution is as follows: 1) Single group: each longitudinal convex component (9) is located at the m-th circumferential division point; 2) Two group: each pair of longitudinal convex components (9) forms a group and maintains a certain interval. Each group of longitudinal convex components (9) is set at the m / 2 circumferential division point. The center of the midpoint of the arc between the two longitudinal convex components (9) coincides with the center of the m / 2 circumferential division point.

6. A method for fabricating a refined model of a large-diameter shield tunnel segment using the fabrication device according to any one of claims 1-5, characterized in that, The process includes the following steps: Step 1: Apply release agent evenly to the surface of the fabrication device, assemble type A, type B, type C and type D components, and install rubber core mold (5), longitudinal boss component (7), steel cage (26), circumferential T-shaped component (13), and longitudinal T-shaped component (14). The circumferential T-shaped component (13) and longitudinal T-shaped component (14) need to be fitted with sleeves (15) at their ends; Step 2: Open the truncated cone cap (22) on type C component (3) to expose the grouting port, inject grout of a material similar to that of the pipe segment into the grouting port, place the fabrication device on a vibrating table for vibration until the grout is level or overflows from the grouting port; Step 3: Adjust the air valve (6) on the rubber core mold to reduce the pressure on the rubber core mold (5). The internal air pressure is reduced to reduce the thickness of the rubber core mold (5) to the thinnest thickness. At this time, observe whether the grout level at the injection port is lower than the top surface of the C-type component (3). If it is higher, cover it with the frustum cap (22); if it is lower or equal to, continue to add grout and make the grout level higher than the top surface of the C-type component (3), and then cover it with the frustum cap (22). Step 4: Place the fabrication device in a constant temperature and humidity environment for curing. After the tunnel model reaches the demolding strength, first remove the pre-embedded circumferential T-shaped component (13) and longitudinal T-shaped component (14), and then remove the C-type component (3), rubber core mold (5), longitudinal boss component (7), B-type component (2), D-type component (4) and A-type component (1) in sequence to finally obtain the tunnel model.

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