A shield tunnel scale model for model test

Abstract

The utility model discloses a kind of shield tunnel scale model for model test, it is related to shield tunnel model test technical field, in view of the great difference between tunnel model and actual engineering in prior art, it is difficult to realize the problem of fine simulation to actual engineering environment, the shield tunnel scale model of the utility model includes multiple lining ring, multiple longitudinal splicing piece, two lining ring end and two connecting ring: multiple lining ring is by multiple segment splicing composition;Multiple longitudinal splicing piece is connected in the outer surface of lining ring;Two lining ring end is by multiple end piece splicing composition;Two connecting rings are respectively arranged on two lining ring end.The utility model is based on similarity theory, both ensure that the transverse and longitudinal structural stiffness of model shield tunnel and prototype tunnel remain consistent, can also reflect the local stress and failure characteristics of segment ring joint, while segment ring joint tensioning deformation data can be obtained, improve the reliability of model test structure.

Description

Technical Field

[0001] This utility model relates to the field of shield tunnel model testing technology, and in particular to a scaled-down shield tunnel model for model testing. Background Technology

[0002] With the advancement of urbanization, the scale of underground space development is expanding rapidly. Shield tunneling technology, with its outstanding advantages such as high construction efficiency and minimal impact on the surrounding environment, is widely used in urban underground engineering construction. This type of tunnel structure is mainly composed of segmented tunnel sections, and the scientific and rational connection structure of these sections plays a crucial role in ensuring core performance indicators such as tunnel integrity, waterproofing, load-bearing capacity, and long-term stability.

[0003] In the current field of shield tunnel research, model testing has become an indispensable research tool. Especially considering that underground engineering accidents are often difficult to observe and effectively control on-site, model testing is particularly important and efficient. Through reasonable simplification and highlighting the impact of key elements, model testing can realistically reproduce the complexities of actual engineering projects. However, current model testing research on shield tunnels typically uses a complete homogeneous circular ring to simulate the tunnel. But compared to reality, in actual underground engineering, each ring of a shield tunnel is assembled from multiple segments. This means that there is a significant difference between the tunnel model used in current tests and the actual engineering project, making it difficult to achieve a detailed simulation of the actual engineering environment. This, to some extent, significantly reduces the reliability and accuracy of the obtained reference data.

[0004] The authorization announcement number CN108776033B describes a lining model and its fabrication method for longitudinal model testing of shield tunnels. It states that "the method of longitudinally splicing segment lining rings to form a segment lining model includes through-joint assembly and staggered joint assembly; it includes several interconnected segment rings, each segment ring having a groove on its side, and longitudinal joint pieces evenly adhered to the outer wall of adjacent segment rings. The longitudinal joint pieces are I-shaped, with their two end flanges respectively laid on two adjacent segment rings; the material of the longitudinal joint pieces is PE material." By adhering longitudinal joint pieces to the adjacent segment rings at positions corresponding to the longitudinal joints of the segment lining structure to be tested, and then adhering the flanges of the longitudinal joint pieces to the adjacent segment rings, a complete segment lining model is formed.

[0005] Compared to reality, in actual underground engineering, each ring of a shield tunnel is assembled from multiple segments. This means that the tunnel model described in the authorization announcement CN108776033B, "A Lining Model and Manufacturing Method for Longitudinal Model Test of Shield Tunnels," differs significantly from the actual engineering project. This makes it difficult to achieve a detailed simulation of the actual engineering environment, thus greatly reducing the credibility and accuracy of the obtained reference data.

[0006] A segment lining structure for shield tunnel model testing, authorized by announcement number CN220893916U, includes multiple longitudinally arranged and interconnected segment rings. Each segment ring has a cutting groove on its surface and a waterstop strip installed on both sides. Adjacent segment rings form a circumferential joint, with a waterproof silicone strip adhered to the inside of the circumferential joint. The surfaces of two adjacent segment rings are connected by a longitudinal joint plate. The two end plates of the longitudinal joint plate are fixed to the corresponding segment rings by joint bolts. Each segment ring has a pre-drilled groove on both end faces for installing the waterstop strip. The two end plates of the longitudinal joint plate have joint plate positioning holes corresponding to the joint bolts. The segment rings have joint positioning screw holes corresponding to the joint bolts arranged circumferentially.

[0007] Using a complete homogeneous circular ring to simulate a shield tunnel means that the tunnel model used in the segment lining structure for shield tunnel model testing (authorization announcement number CN220893916U) differs significantly from the actual engineering model, making it difficult to achieve a detailed simulation of the actual engineering environment. This, in turn, significantly reduces the credibility and accuracy of the obtained reference data.

[0008] To further enhance the effectiveness of model tests and obtain more reliable and accurate experimental data, there is an urgent need to develop a scaled-down model of a shield tunnel that can more accurately and realistically reflect actual engineering conditions. This will not only provide a more solid experimental basis for theoretical research and technological development related to shield tunnels, but also help promote technological progress and development in the entire field of underground engineering. Utility Model Content

[0009] To address the aforementioned problems, this utility model aims to provide a scaled-down shield tunnel model for model testing. The main body of the scaled-down shield tunnel model is composed of multiple lining rings and multiple longitudinal splices. The ends of two lining rings are respectively connected to both ends of the main body of the scaled-down shield tunnel model, and two connecting rings are respectively set on the ends of the two lining rings to simulate the reinforcement structure at both ends of the shield tunnel. After splicing, the gaps are filled with silicone rubber, solving the practical problem of insufficient dimensional accuracy in model making and reducing the assembly difficulty. The elasticity of silicone rubber can simulate the micro-deformation capability of the prototype segment joint, making the stress on the model closer to the real state. Furthermore, its longitudinal splicing segments are made of high-density polyethylene (HDPE), which has certain toughness and strength, as well as strong corrosion resistance. In model tests, it can stably simulate the connection stiffness of the prototype joint, while avoiding the stiffness redundancy that may be caused by metal materials. Especially when subjected to long-term loading or simulating groundwater environment, based on similarity theory, it ensures that the transverse and longitudinal structural stiffness of the model shield tunnel is consistent with that of the prototype tunnel, and can reflect the local stress and failure characteristics of the segment circumferential joint. At the same time, it can obtain the tension deformation data of the segment circumferential joint, thus improving the reliability of the model test structure.

[0010] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A scaled-down model of a shield tunnel for model testing, the scaled-down model of the shield tunnel comprising: Multiple lining rings, composed of multiple segments, are spliced ​​together to form the main body of the scaled-down model of the shield tunnel; Multiple longitudinal splicing pieces are connected to the outer surface of the lining ring to connect adjacent lining rings; The two lining ring ends are composed of multiple end pieces spliced ​​together. One is set at the front end of the shield tunnel scale model body, and the other is set at the rear end of the shield tunnel scale model body. Two connecting rings are respectively set at the ends of the two lining rings to reinforce both ends of the main body of the scaled-down shield tunnel model.

[0011] The segments include: A dovetail tenon is located at one end of the tube segment; The dovetail tenon is located at the other end of the segment; Two sets of longitudinal bolt holes are symmetrically opened on the outer surface of the tube segment.

[0012] The end piece includes: A connecting groove is formed on the end side of the end piece for connecting a connecting ring; Longitudinal bolt holes are symmetrically opened on the outer surface of the end piece near the tube segment, and are used to connect the tube segment.

[0013] The connecting ring includes: A retaining ring is fitted onto the outer side of the end of the lining ring; The connector strip is fixedly connected to the inner circumference of the retaining ring and is used to connect to the connecting groove on the end piece.

[0014] The longitudinal splicing piece is connected between two lining rings by fixing bolts and longitudinal bolt holes, and is used to connect two adjacent lining rings.

[0015] The longitudinal splicing piece is connected between the lining ring and the end of the lining ring by fixing bolts and longitudinal bolt holes, and is used to connect adjacent lining rings and the end of the lining ring.

[0016] The beneficial effects of this utility model are: The longitudinal splicing pieces of this invention are made of high-density polyethylene. After splicing, the gaps are filled with silicone rubber, which solves the practical problem of insufficient dimensional accuracy in model making and reduces the difficulty of assembly. The elasticity of silicone rubber can simulate the small deformation capacity of the prototype segment joint, making the stress on the model closer to the real state. High-density polyethylene (HDPE) has certain toughness and strength, and strong corrosion resistance. In model tests, it can stably simulate the connection stiffness of the prototype joint, while avoiding the stiffness redundancy that may be caused by metal materials. Especially when subjected to long-term loading or simulating groundwater environment, based on similarity theory, it ensures that the transverse and longitudinal structural stiffness of the model shield tunnel is consistent with that of the prototype tunnel, and can reflect the local stress and failure characteristics of the segment circumferential joint. At the same time, it can obtain the tension deformation data of the segment circumferential joint, improving the reliability of the model test structure.

[0017] The connecting ring in this invention includes a fixing ring and a plug strip. The fixing ring is sleeved on the outside of the end of the lining ring, and the plug strip is fixedly connected to the inner circumference of the fixing ring and is adapted to the connecting groove opened on the end side of the end piece. This allows the two lining ring ends to be installed at both ends of the main body of the shield tunnel scale model. In the model test, it can stably simulate the connection stiffness of the prototype joint. Based on similarity theory, it ensures that the transverse and longitudinal structural stiffness of the model shield tunnel is consistent with that of the prototype tunnel.

[0018] In this invention, multiple lining rings, multiple longitudinal splicing pieces, and the ends of two lining rings are spliced ​​together to form the main body of a scaled-down model of a shield tunnel. The upper and lower flanges of the I-shaped structure can disperse the pressure transmitted by the longitudinal fixing bolts, while the longitudinal splicing pieces bear the shear force. Compared with flat splicing pieces, it can more evenly transmit the force of one lining ring to the adjacent rings, avoiding splicing piece deformation or segment bolt hole damage caused by local stress concentration, and better conforming to the "longitudinal overall stress" characteristic of the prototype tunnel. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2This is a schematic diagram of the mating structure of the connecting ring and the lining ring end of this utility model.

[0021] Figure 3 This is a schematic diagram of the structure of the lining ring end of this utility model.

[0022] Figure 4 This is a schematic diagram of the lining ring of this utility model.

[0023] Figure 5 This is a schematic diagram of the outer structure of the tube segment of this utility model.

[0024] Figure 6 This is a schematic diagram of the inner structure of the tube segment of this utility model.

[0025] Figure 7 This utility model Figure 1 A magnified structural diagram of point A in the middle.

[0026] Figure 8 This is a schematic diagram of the inner structure of the end piece of this utility model.

[0027] Figure 9 This is a schematic diagram of the outer structure of the end piece of this utility model.

[0028] Figure 10 This is a schematic diagram of the connecting ring of this utility model.

[0029] The components are: 1. Lining ring end; 2. Connecting ring; 3. Pipe segment; 4. Longitudinal splice piece; 5. Longitudinal bolt hole; 6. Connecting groove; 7. Dovetail tenon; 8. Dovetail mortise; 9. Fixing bolt; 10. End piece; 11. Fixing ring; 12. Insert strip. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solution of this utility model, the technical solution of this utility model will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] See attached document Figure 1-10 The diagram shows a scaled-down shield tunnel model for model testing. The scaled-down shield tunnel model includes multiple lining rings, multiple longitudinal splicing pieces 4, two lining ring ends 1, and two connecting rings 2. The multiple lining rings are composed of multiple tunnel segments 3 spliced ​​together to form the main body of the scaled-down shield tunnel model. The multiple longitudinal splicing pieces 4 are connected to the outer surface of the lining rings to connect adjacent lining rings. The two lining ring ends 1 are composed of multiple end pieces 10 spliced ​​together, one located at the front end of the main body of the scaled-down shield tunnel model and the other at the rear end. The two connecting rings 2 are respectively located on the two lining ring ends 1 to reinforce both ends of the main body of the scaled-down shield tunnel model.

[0032] Specifically, such as Figure 1 As shown, the main body of the scaled-down shield tunnel model is composed of multiple lining rings and multiple longitudinal splicing pieces 4. The two lining ring ends 1 are respectively connected to the two ends of the main body of the scaled-down shield tunnel model. Two connecting rings 2 are respectively set on the two lining ring ends 1 to simulate the reinforcement structure at both ends of the shield tunnel. The longitudinal splicing pieces 4 are made of high-density polyethylene. After splicing, the gaps are filled with silicone rubber to solve the problem of insufficient dimensional accuracy in model making and reduce the assembly difficulty. The elasticity of silicone rubber can simulate the small deformation capacity of the prototype segment joint, making the stress of the model closer to the real state. High-density polyethylene (HDPE) has certain toughness and strength and strong corrosion resistance. In the model test, it can stably simulate the connection stiffness of the prototype joint, while avoiding the stiffness redundancy that may be caused by metal materials. Especially when subjected to long-term loading or simulating groundwater environment, based on similarity theory, it can ensure that the transverse and longitudinal structural stiffness of the shield tunnel model is consistent with that of the prototype tunnel, and can reflect the local stress and failure characteristics of the segment joint. At the same time, it can obtain the tension deformation data of the segment joint, improving the reliability of the model test structure.

[0033] In some embodiments, the segment 3 includes a dovetail tenon 7, a dovetail tenon eye 8, and two sets of longitudinal bolt holes 5: the dovetail tenon 7 is disposed at one end of the segment 3; the dovetail tenon eye 8 is disposed at the other end of the segment 3; and the two sets of longitudinal bolt holes 5 are symmetrically opened on the outer surface of the segment 3.

[0034] Specifically, such as Figure 1 , Figure 4 , Figure 5 and Figure 6 As shown, each lining ring is composed of multiple pipe segments 3 spliced ​​together. Dovetail tenons 7 and dovetail mortises 8 are fixedly connected to both ends of the pipe segments 3. The pipe segments 3 are spliced ​​together to form the lining ring through the dovetail tenons 7 and dovetail mortises 8. Two sets of longitudinal bolt holes 5 are symmetrically opened on the outer surface of each pipe segment 3 to avoid the "alignment deviation" of splicing in a single direction, improve the stability of circumferential assembly, and the honeycomb structure disperses the force, simulating the characteristic of uniform circumferential force on the prototype pipe segments. The dovetail inclination angle is 22°, in which the inclined surface can generate radial constraint force to prevent the pipe segments 3 from circumferentially shifting when subjected to force (such as earth pressure). In addition, the mold is designed with tolerances, and the gaps are filled with silicone rubber after splicing to solve the practical problem of insufficient dimensional accuracy in model making, reduce the assembly difficulty, and the elasticity of silicone rubber can simulate the small deformation capacity of the prototype pipe segment joints, making the stress on the model closer to the real state.

[0035] In some embodiments, the end piece 10 includes a connecting groove 6 and longitudinal bolt holes 5: the connecting groove 6 is formed on the end side of the end piece 10 for connecting the connecting ring 2; the longitudinal bolt holes 5 are symmetrically formed on the outer surface of the end piece 10 near the tube segment 3 for connecting the tube segment 3. The connecting ring 2 includes a fixing ring 11 and a plug strip 12: the fixing ring 11 is sleeved on the outside of the lining ring end 1; the plug strip 12 is fixedly connected to the inner circumference of the fixing ring 11 for connecting the connecting groove 6 on the end piece 10.

[0036] Specifically, such as Figure 2 , Figure 3 , Figure 8 , Figure 9 and Figure 10 As shown, each lining ring end 1 is spliced ​​from multiple end pieces 10. Dovetail tenons 7 and dovetail mortises 8 are fixedly connected to both ends of the end piece 10. The lining ring end 1 is connected to both ends of the shield tunnel scale model body through longitudinal splicing pieces 4. The end side of the end piece 10 is provided with a connecting groove 6. The outer surface of the end piece 10 near the tube segment 3 is provided with a longitudinal bolt hole 5. The connecting ring 2 includes a fixing ring 11 and a plug strip 12. The fixing ring 11 is sleeved on the outside of the lining ring end 1. The plug strip 12 is fixedly connected to the inner circumference of the fixing ring 11 and is adapted to the connecting groove 6 opened on the end side of the end piece 10. This allows the two lining ring ends 1 to be installed at both ends of the shield tunnel scale model body. In the model test, it can stably simulate the connection stiffness of the prototype joint. Based on similarity theory, it ensures that the transverse and longitudinal structural stiffness of the model shield tunnel is consistent with that of the prototype tunnel.

[0037] In some embodiments, the longitudinal splicing piece 4 is connected between two lining rings by fixing bolts 9 and longitudinal bolt holes 5, for connecting two adjacent lining rings. The longitudinal splicing piece 4 is also connected between a lining ring and a lining ring end 1 by fixing bolts 9 and longitudinal bolt holes 5, for connecting adjacent lining rings and lining ring end 1.

[0038] Specifically, such as Figure 1 and Figure 7 As shown, the longitudinal splicing piece 4 is I-shaped, with longitudinal bolt holes 5 on both sides of the I-shape. The longitudinal bolt holes 5 on both sides of the I-shape are connected to the longitudinal bolt holes 5 on the end piece 10 and the two sets of longitudinal bolt holes 5 symmetrically opened on the segment 3 through fixing bolts 9. This allows multiple lining rings, multiple longitudinal splicing pieces 4 and two lining ring ends 1 to be spliced ​​together to form the main body of the shield tunnel scale model. The upper and lower flanges of the I-shaped structure can disperse the pressure transmitted by the longitudinal fixing bolts 9, while the longitudinal splicing pieces 4 bear the shear force. Compared with flat splicing pieces, it can more evenly transmit the force of one lining ring to the adjacent ring, avoiding splicing piece deformation or segment bolt hole damage caused by local stress concentration, and better conforming to the "longitudinal overall stress" characteristics of the prototype tunnel.

[0039] The fabrication method for the scaled-down shield tunnel model used in this example for model testing includes the following steps: a. Determine the similarity ratio of the test, including the geometric and mechanical similarity relationships of the segment lining structure and longitudinal joint plate in the model test. The geometric similarity relationship mainly includes the outer diameter, thickness and width of the segment ring, the effective length, width and thickness of the longitudinal joint plate, and the mechanical similarity relationship mainly includes the elastic modulus Ec and the standard value of uniaxial compressive strength fcu of the segment lining structure, as well as the elastic modulus Eb and tensile stiffness kt of the longitudinal joint plate.

[0040] b. Determine the ratio of gypsum and water, mix water and imitation porcelain gypsum in a certain proportion to make a uniaxial compression standard specimen, and measure the uniaxial compressive strength fcu and elastic modulus Ec of gypsum through testing. By adjusting the water-gypsum ratio multiple times, the mechanical parameters of the adjusted gypsum are made to meet the set error range.

[0041] c. Based on the adjusted gypsum material ratio, cast multiple model segment rings sequentially, ensuring that the dimensions of the model segment rings meet the geometric similarity ratio.

[0042] d. Joint positioning screw holes for installing joint bolts are provided along the circumferential direction of the segment ring.

[0043] e. Fabricate a longitudinal joint plate with a positioning hole diameter of 5mm. Ensure that the tensile stiffness of the longitudinal joint plate meets the following similarity ratio: Ckt = CL × CE, where Ckt is the tensile stiffness similarity ratio of the circumferential joint bolt, CL is the geometric similarity ratio, and CE is the elastic modulus similarity ratio.

[0044] f. Set a cutting groove for each segment of the end lining ring, and embed a 3D printed self-made connecting ring into the cutting groove to fix each segment and ensure stability.

[0045] g. First, the fabricated segments are longitudinally spliced ​​into lining rings using dovetail tenons and dovetail mortises, and then adjacent lining rings are connected using longitudinal joint plates.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A scaled-down model of a shield tunnel for model testing, characterized in that, The scaled-down model of the shield tunnel includes: Multiple lining rings are spliced ​​together from multiple segments (3) to form the main body of the scaled-down model of the shield tunnel; Multiple longitudinal splicing pieces (4) are connected to the outer surface of the lining ring to connect adjacent lining rings; The two lining ring ends (1) are composed of multiple end pieces (10) spliced ​​together. One is set at the front end of the shield tunnel scale model body and the other is set at the rear end of the shield tunnel scale model body. Two connecting rings (2) are respectively set on the ends (1) of the two lining rings to reinforce the two ends of the shield tunnel scale model body.

2. A scaled-down model of a shield tunnel for model testing according to claim 1, characterized in that, The segment (3) includes: A dovetail tenon (7) is provided at one end of the tube segment (3); Dovetail tenon (8) is set at the other end of the tube segment (3); Two sets of longitudinal bolt holes (5) are symmetrically opened on the outer surface of the tube segment (3).

3. A scaled-down model of a shield tunnel for model testing according to claim 1, characterized in that, The end piece (10) includes: A connecting groove (6) is provided on the end side of the end piece (10) for connecting the connecting ring (2). Longitudinal bolt holes (5) are symmetrically opened on the outer surface of the end piece (10) near the tube piece (3) for connecting the tube piece (3).

4. A scaled-down model of a shield tunnel for model testing according to claim 1, characterized in that, The connecting ring (2) includes: A fixing ring (11) is fitted onto the outside of the end (1) of the lining ring; The plug strip (12) is fixedly connected to the inner circumference of the fixing ring (11) and is used to connect to the connecting groove (6) on the end piece (10).

5. A scaled-down model of a shield tunnel for model testing according to claim 1, characterized in that, The longitudinal splicing piece (4) is connected between two lining rings by fixing bolts (9) and longitudinal bolt holes (5) to connect two adjacent lining rings.

6. A scaled-down model of a shield tunnel for model testing according to claim 1, characterized in that, The longitudinal splicing piece (4) is connected between the lining ring and the end of the lining ring (1) by means of the fixing bolt (9) and the longitudinal bolt hole (5), and is used to connect the adjacent lining ring and the end of the lining ring (1).

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