CN116117991A - A mold for making a scale model of a shield tunnel - Google Patents

Abstract

The invention relates to a mould for manufacturing a shield tunnel scale model, which is characterized in that wedge-shaped bulges are arranged at longitudinal joints and circumferential joints of the mould so as to reduce the effective cross section of a poured segment structure model at the longitudinal joints and the circumferential joints, wherein an outer mould is made of a rigid material, an inner mould is made of a flexible material, an inner mould and an outer mould are spliced by adopting four quarter-ring moulds, and after concrete pouring is finished, the four quarter-rings can be detached respectively, so that the mould is easy to release. Compared with the prior art, the invention can simulate the weakening of the structural strength of the splicing position of the longitudinal seam and the circumferential seam of the segment in the real tunnel environment by utilizing the wedge-shaped bulge under the condition of full-ring casting, and does not need to separately cast the segment and splice the segment. The invention comprehensively considers the weakening of the strength of the longitudinal seam and the circular seam of the actual tunnel model and the convenience of disassembling the mold after pouring, has the characteristics of convenient use and high reduction degree, and can create good economic benefit and scientific research value.

Description

A mold for making a scale model of a shield tunnel

technical field

The invention relates to the field of tunnel engineering, in particular to a mold for making a scale model of a shield tunnel.

Background technique

In recent years, with the continuous advancement of the urbanization process, the population of large and medium-sized cities has increased suddenly, and traffic pressure has become a difficult problem for cities. In this context, the utilization of underground space has become the focus of urban planning and construction. Among them, the subway shield tunnel has the advantages of fast construction speed, manpower saving, and small impact on the surface, and has gradually become the mainstream of urban underground transportation construction. However, the urban underground environment has considerable uncertainty, which brings challenges to shield tunnel construction and structural design. Therefore, it is often necessary to complete shield tunnel structural model tests before shield tunnel construction to explore specific construction methods. feasibility or the safety of the shield tunnel structure.

The structural model test of the shield tunnel depends on the fabrication of the segment model. Since most of the existing shield tunnel segments are made of reinforced concrete, molds need to be made in advance for concrete pouring. However, since shield tunnels need to be spliced with segments, the splicing longitudinal joints and circular joints are left after splicing, and the structural strength of the joints is bound to be weakened to a certain extent; It is difficult to take out because of the bonding between the concrete and the mold, resulting in the difficulty of demoulding; especially when the whole ring is poured, the inner mold is wrapped by concrete, and its removal is extremely difficult. To solve the above problems, the method of pouring segments piece by piece can be adopted, but this method is time-consuming and laborious, and it is easy to cause damage to the model. It cannot well meet the construction party's needs for convenient and fast testing, and it is difficult to adapt to the rapid construction of urban subways. .

Contents of the invention

The purpose of the present invention is to provide a mold for making a shield tunnel scale model in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

A mold for making a scale model of a shield tunnel, including an outer mold and an inner mold, the inner mold is nested in the outer mold, and the outer mold and the inner mold are two concentric rings;

The annular inner surface of the outer mold is provided with an outer mold annular seam and an inner protrusion of the outer mold;

The outer surface of the ring of the inner mold is provided with an outer protrusion of the inner mold.

Further, the inner protrusions of the outer mold and the outer protrusions of the inner mold are wedge-shaped protrusions, which are convenient for rapid demoulding after casting.

Further, the outer mold is an outer mold made of rigid material.

Further, the inner mold is made of flexible material.

Further, the outer protrusion of the inner mold is a wooden rib, and the wooden rib is fixed on the outer surface of the inner mold.

Further, the inner mold is positioned and nested in the outer mold through wooden support.

Further, the annular seam of the outer mold and the inner protrusion of the outer mold are welded to the circular inner surface of the outer mold.

Further, the outer mold and the inner mold are respectively divided into four ring pieces along the radial direction, and the four ring pieces are spliced to form a complete ring.

Further, the annular seam of the outer mold and the inner protrusion of the outer mold are used to simulate a positive bending moment;

The inner and outer protrusions are used to simulate negative bending moments.

Further, the protrusion heights of the inner protrusions of the outer mold and the outer protrusions of the inner mold are determined by the bending stiffness reduction coefficient of the longitudinal seam relative to the segment, and the protrusion height is set according to the bending stiffness reduction coefficient so that the stiffness is equivalent to ;

The theoretical calculation formula is:

In the formula, EI represents the bending stiffness of the segment, EI _represents the bending stiffness of the joint, E is the elastic modulus of the segment material, I is the moment of inertia of the section, h is the thickness of the segment, b is the ring width of the segment, and H is The thickness of the segment at the joint, λ is the reduction factor of the bending stiffness.

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

1. In the present invention, by setting protrusions on the inner mold to simulate negative bending moments, and setting protrusions on the outer membrane to simulate positive bending moments, in the case of whole ring casting, the cast segment structure model can be placed at the longitudinal joint and the ring joint. The effective section is reduced, so as to better simulate the weakening of the structural strength at the splicing of the segment longitudinal seam and the annular seam in the real tunnel environment.

2. Using the mold proposed by the present invention to make a model, and adopting the whole ring pouring method, the multi-ring tunnel segments can be poured directly at the same time, saving the segment production time, without pouring the segments separately and then splicing them.

3. In the present invention, the inner mold and the outer mold are respectively divided into four ring pieces in the radial direction, and the four ring pieces are spliced to form a whole ring, so that the mold can be easily disassembled after the pouring is completed, and the outer mold can be directly divided along the diameter of the pipe piece. without pulling it out slowly in the axial direction.

4. The outer mold in the present invention is made of rigid material, and the outer mold can be recycled. When dismantled, it can be pulled out directly in the radial direction instead of in the axial direction. The inner mold is made of soft material, which is not only convenient to make, but also easy to tear, so that it can be disassembled quickly and saves demoulding time.

Description of drawings

Fig. 1 is the structural representation of outer mold of the present invention;

Fig. 2 is the internal mold structure schematic diagram of the present invention;

Figure 3 is a schematic diagram of the poured shield tunnel segment.

Reference signs: 1-outer mold, 2-circular seam of outer mold, 3-inner protrusion of outer mold, 4-outer protrusion of inner mold, 5-inner mold, 6-inner longitudinal seam of segment, 7-outer segment Longitudinal seam, 8-segment circular seam.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is carried out on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

In view of the problems existing in the production of shield tunnel models and the defects of block casting in the prior art, the present invention proposes a mold for making a scaled-scale model of shield tunnels. Considering that the wedge-shaped protrusions of the mold are set on the premise of whole-circle pouring, Grooves appear in the segment model to simulate the weakening characteristics of the section strength; the grooves for simulating longitudinal joints are divided into inner grooves and outer grooves. At the same time, the whole ring is spliced by 4 1/4 ring molds, the outer mold is made of rigid material, and the inner mold is made of flexible material, which is convenient for demoulding after pouring.

Specifically, as shown in Figure 1-3, the mold includes an outer mold 1 and an inner mold 2, the inner mold 2 is nested in the outer mold 1, and the outer mold 1 and the inner mold 2 are two concentric rings;

The inner surface of the ring of the outer mold 1 is provided with an annular seam 2 of the outer mold and an inner protrusion 3 of the outer mold; the outer surface of the ring of the inner mold 2 is provided with an outer protrusion 4 of the inner mold, which is used to reduce the effective cross-sectional area of the seam .

In this embodiment, the inner protrusions 3 of the outer mold and the outer protrusions 4 of the inner mold are configured as wedge-shaped protrusions, which facilitates the model to fall off after the model is made.

The outer mold 1 and the inner mold 2 are respectively divided into four ring pieces along the radial direction, and the four ring pieces are spliced to form a complete ring. The annular seam 2 of the outer mold and the inner protrusion 3 of the outer mold are welded to the inner surface of the ring of the outer mold 1 . The outer protrusion 4 of the inner mold is a wooden rib, and the wooden rib is fixed on the outer surface of the ring of the inner mold 2 .

The outer mold 1 is an outer mold made of a rigid material, and the inner mold 2 is an inner mold made of a flexible material. In this embodiment, the outer mold 1 is made of steel plate, and the outer mold can be recycled. When dismantled, it can be pulled out directly in the radial direction instead of in the axial direction. The inner mold 2 is made of flexible PVC sheet, which is not only convenient to manufacture, but also flexible and easy to tear, so that it can be disassembled quickly and saves demoulding time.

In this embodiment, the inner mold 2 is positioned and nested in the outer mold 1 through the support of wooden boards.

Compared with the prior art, the mold for making the scaled-scale model of the shield tunnel proposed by the present invention can better simulate the structural strength of the segment longitudinal seam and the ring seam joint in the real tunnel environment under the condition of whole ring pouring. weaken. Among them, it is necessary to find the position of the longitudinal seam that bears the positive and negative bending moments through structural calculation, set the protrusion on the inner mold 2 to simulate the negative bending moment, and set the protrusion on the outer membrane 1 to simulate the positive bending moment. Furthermore, the bending stiffness reduction coefficient of the longitudinal seam relative to the segment is calculated theoretically, and the depth of the groove is set according to the coefficient to make the stiffness equivalent.

The theoretical calculation formula is:

In the formula, EI represents the bending stiffness of the segment, EI _represents the bending stiffness of the joint, E is the elastic modulus of the segment material, I is the moment of inertia of the section, h is the thickness of the segment, b is the ring width of the segment, and H is The thickness of the segment at the joint, λ is the reduction factor of the bending stiffness.

The convex design makes the poured tunnel segments have annular seams, and can directly pour multi-ring tunnel segments at the same time, saving the production time of the segments without pouring and splicing the segments separately; the invention can also successfully complete the pouring After the disassembly of the mold, the mold can be directly removed along the radial direction of the segment without slowly pulling out along the axial direction.

The invention comprehensively considers the weakening of the strength of the longitudinal seam and annular seam of the actual tunnel model, and the convenience of removing the formwork after pouring, has the characteristics of convenient use and high reduction degree, and can create good economic benefits and scientific research value.

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to 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 experiments on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims (10)

1. The mould for manufacturing the shield tunnel scale model is characterized by comprising an outer mould (1) and an inner mould (2), wherein the inner mould (2) is nested in the outer mould (1), and the outer mould (1) and the inner mould (2) are two concentric rings;

the inner surface of the circular ring of the outer mold (1) is provided with an outer mold circumferential seam (2) and an outer mold inner bulge (3);

an inner mold outer bulge (4) is arranged on the outer surface of the circular ring of the inner mold (2).

2. The mould for manufacturing the shield tunnel scale model according to claim 1, wherein the outer mould inner bulge (3) and the inner mould outer bulge (4) are wedge-shaped bulges.

3. A mould for making a scaled mould for a shield tunnel according to claim 1, characterized in that the outer mould (1) is an outer mould made of a rigid material.

4. A mould for making a scaled model of a shield tunnel according to claim 1, characterized in that the inner mould (2) is an inner mould made of flexible material.

5. The mould for manufacturing a shield tunnel scale model according to claim 1, wherein the inner mould outer bulge (4) is a wooden rib which is fixed on the outer surface of the circular ring of the inner mould (2).

6. A mould for manufacturing a shield tunnel scale model according to claim 1, characterized in that the inner mould (2) is nested in the outer mould (1) by means of plank support positioning.

7. The mould for manufacturing the shield tunnel scale model according to claim 1, wherein the outer mould circumferential seam (2) and the outer mould inner bulge (3) are welded on the inner surface of the circular ring of the outer mould (1).

8. The mould for manufacturing the shield tunnel scale model according to claim 1, wherein the outer mould (1) and the inner mould (2) are respectively divided into four annular sheets along the radial direction, and the four annular sheets are spliced to form a whole ring.

9. The mould for manufacturing the shield tunnel scale model according to claim 1, wherein the external mould circumferential seam (2) and the external mould inner bulge (3) are used for simulating positive bending moment;

the inner mold outer bulge (4) is used for simulating a hogging moment.

10. The mold for manufacturing a shield tunnel scale model according to claim 1, wherein the protrusion heights of the outer mold inner protrusion (3) and the inner mold outer protrusion (4) are determined by bending rigidity reduction coefficients of longitudinal slits relative to the segments, and the protrusion heights are set according to the bending rigidity reduction coefficients so that the rigidity is equivalent;

the theoretical calculation formula is:

wherein EI represents the bending rigidity of the segment, EI _{Splicing joint} Elastic die for expressing bending stiffness of joint and E being duct piece materialThe quantity I is the section moment of inertia, H is the thickness of the duct piece, b is the annular width of the duct piece, H is the thickness of the duct piece at the joint, and lambda is the bending rigidity reduction coefficient.

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