CN111660409A - Large-span tunnel lining model prefabricating device and method in geomechanical model test - Google Patents

Abstract

The invention relates to a large-span tunnel lining model prefabricating device and method in a geomechanical model test. The device and the method are suitable for a tunnel lining embedding method in a geomechanical model test, namely, a tunnel lining is firstly manufactured, the geomechanical model filler is embedded into the tunnel lining after reaching a certain height, then the filler is embedded into the tunnel lining in a certain thickness, and finally the procedures of loading, deformation, stress monitoring and the like of the test are carried out. The invention can manufacture tunnel linings with different lengths, thicknesses and flattening rates according to the research requirement, solves the problem that the model lining is difficult to manufacture, and has simple structure, convenient disassembly and reuse, low manufacturing cost and wide application space.

Description

Large-span tunnel lining model prefabricating device and method in geomechanical model test

Technical Field

The invention belongs to the technical field of geomechanics, and particularly relates to a device and a method for pouring a special mold prefabricated tunnel secondary lining model with lining similar materials in a geomechanics model test.

Background

At present, China is the world with the largest tunnel engineering scale, the largest quantity and the fastest construction speed. Due to the uncertainty of influence factors such as geological conditions, climatic conditions, support design parameters, building material characteristics, operation and maintenance conditions and the like, disasters such as lining cracking, falling off and dropping blocks, inverted arch uplift and the like of a large number of operating tunnels seriously affect the service performance and service life of the tunnels, even threaten the safety of vehicles in the tunnels, and cause serious consequences such as traffic interruption, casualties and the like and adverse social influence. Meanwhile, the cracking and the damage of the tunnel structure are often accompanied by the phenomena of water leakage, steel bar corrosion, freezing damage and the like, are the most typical diseases during the operation of tunnel engineering, can aggravate the damage process of the tunnel lining structure, make the tunnel not reach the design service life and need to be maintained, and seriously affect the normal operation and the structural durability of the tunnel. Therefore, it is essential to study the crack of the tunnel lining and the disaster generated during the operation.

The geomechanical model test of the tunnel lining in the operation period is different from the geomechanical model test of the tunnel in the construction period, and unnecessary excavation supporting procedures are reduced because the tunnel lining needs to be prefabricated. The method for prefabricating the tunnel lining at the present stage is less in research, methods such as manual formwork erecting filling and steel mould cast-in-place are mainly adopted, the manual formwork erecting filling has the advantages of long manufacturing period and low repeated rate due to complicated procedures, the prefabricated tunnel lining has large dimension error, and the manufacturing device and the method which have the advantages of high precision, short period and high repeated rate are difficult to realize; although the defects of low lining manufacturing precision, low repetition rate and long period are overcome by steel mould cast-in-place, the defects of low yield caused by the fact that the rigidity of the cast lining material is low and the rigidity of a steel mould is high are easily caused by cracking and damage of the model lining during disassembly.

The invention patent with the application number of 201711352524.7 provides a tunnel lining prefabricating and pre-burying device and method in a geomechanical model test, wherein a space formed by connecting a splicing type outer frame, a central core plate, a bottom plate and bolts is a tunnel lining space. Because the initial pouring strength and rigidity of the lining similar material are far lower than those of a steel mould, lining cracking is easily caused, the waste yield of the material is low, reinforcing steel bars are not beneficial to being embedded in the mould to truly simulate the reinforced concrete material on site, and the application range is limited.

Disclosure of Invention

The invention provides a large-span tunnel lining model prefabricating device and method in a geomechanical model test, aiming at overcoming the defects that a model and a mold are in one-to-one correspondence in the existing secondary lining model preparation, the mold cannot be reused, and a model containing reinforcing ribs inside cannot be prepared.

The technical scheme of the invention is as follows:

the utility model provides a large-span tunnel lining model prefabricating device in geomechanical model test which characterized in that: the inner mold and the outer mold are arranged between the bottom plate and the top plate and form a pouring cavity of a secondary lining model; the inner mold and the outer mold are formed by laminating a plurality of flat plates in the vertical direction, and each plate is split into two halves in the horizontal direction; a plurality of through holes are formed in the corresponding positions of the inner die, the outer die, the bottom plate and the top plate, and the prefabricated device is fixed into a whole by the fixing columns penetrating through the through holes; the top plate is provided with a plurality of feed openings.

In the large-span tunnel lining model pre-preparation device in the geomechanical model test, the outer side of the inner mold is provided with the foam buffer layer.

In the large-span tunnel lining model pre-preparation device in the geomechanical model test, a plurality of circumferential reinforcing ribs are arranged in a cavity between the inner mold and the outer mold, the foam buffer layer is provided with a plurality of positioning support rods, and the circumferential reinforcing ribs are fixed on the positioning support rods.

In the large-span tunnel lining model pre-preparation device in the geomechanical model test, the annular reinforcing ribs and the positioning supporting rods are iron wires welded together.

In the large-span tunnel lining model pre-preparation device in the geomechanical model test, the feed opening is a plurality of arc-shaped through grooves arranged at the upper part of the secondary lining model pouring cavity.

In the large-span tunnel lining model pre-preparation device in the geomechanical model test, the plate is a PVC plate, an acrylic plate or a wood plate.

A prefabrication method of a tunnel lining model in a geomechanical model test comprises the following steps:

【1】 Preparing an article: scaling the cross section of the tunnel secondary lining model according to a certain proportion according to the requirements of a geomechanical model test, and preparing a bottom plate and a top plate with corresponding sizes and splicing plates of an internal mold and an external mold according to the scaled secondary lining model structure;

【2】 Inner die splicing: inserting a fixed column into a through hole at a corresponding position of the inner mold on the bottom plate, and splicing the inner mold to a set height;

【3】 And (3) laying the circumferential reinforcing ribs: winding a foam buffer layer on the outer side of the inner die, and inserting one end of the positioning support rod into the foam buffer layer; arranging an outer side circumferential reinforcing rib and an inner side circumferential reinforcing rib in a secondary lining model pouring cavity, so that the outer side circumferential reinforcing rib and the inner side circumferential reinforcing rib are fixed at the outer leakage end of the positioning support rod;

【4】 Outer mold splicing: splicing the outer mold to a set height, inserting the corresponding fixing column of the outer mold, and installing a top plate to fix the prefabricated device into a whole;

【5】 Pouring: pouring lining materials with a certain mixing proportion into the prefabricated cavity through a blanking opening, and standing for a set time;

【6】 Removing the mold: and removing the top plate, the inner mold, the outer mold and the fixing column layer by layer, and removing the foam buffer layer to obtain the secondary lining model.

In the method for prefabricating the large-span tunnel lining model in the geomechanical model test, the standing time is 24 hours.

In the method for prefabricating the large-span tunnel lining model in the geomechanical model test, in the step (6), the dismantling sequence is that the inner mold is dismantled firstly, and then the outer mold is dismantled; when the inner mold and the outer mold are disassembled, the fixing columns are pulled out first, and then the plates of the inner mold and the outer mold are sequentially disassembled.

The invention has the following beneficial effects:

1. the invention provides a large-span tunnel lining model prefabricating device and method in a geomechanical model test, which overcome the defects of low precision, low yield, low repetition rate and long period of the traditional lining manufacture, and simultaneously reduce the manufacture cost and the weight of the prefabricating device.

2. The inner mold and the outer mold of the lining model prefabricating device are spliced into different lengths by adopting plates, the requirements of tunnel tests with different lengths in model tests are met, and meanwhile, the inner mold, the outer mold, the top plate and the bottom plate of the mold can be repeatedly used, so that the test cost is reduced.

3. According to the invention, the foam buffer layer is arranged on the outer ring of the inner die, and the inner die and the poured secondary lining model are isolated, so that on one hand, the inner die is convenient to take out during die stripping, the dimensional structural integrity of the secondary lining is ensured, on the other hand, the foam buffer layer can be used as a supporting piece, the arrangement of the inner circumferential reinforcing ribs and the outer circumferential reinforcing ribs is realized by inserting a plurality of positioning support rods, and the preparation of the secondary lining model internally containing the circumferential reinforcing ribs and the stirrups is realized, thereby meeting the accuracy and reliability of a tunnel mechanical model test.

4. The inner mold and the outer mold are formed by cutting a PVC plate, an acrylic plate or a wood plate through a laser engraving machine, are simple to manufacture, light in weight and low in manufacturing cost, can accurately control the size of the secondary lining in processing, and have the advantages of simple manufacturing method, reusability and short period.

Drawings

FIG. 1 is a layout diagram of a secondary lining reinforcing steel bar of a conventional tunnel;

FIG. 2 is a schematic structural diagram of a prefabricating apparatus for a secondary lining model of a tunnel according to the present invention;

FIG. 3 is a schematic cross-sectional view of an inner mold and an outer mold of the present invention;

FIG. 4 is a schematic view of the bottom plate structure of the present invention;

FIG. 5 is a schematic view of the top plate structure of the present invention;

FIG. 6 is a schematic view of the foam cushioning layer, reinforcing ribs and positioning struts of the present invention.

The reference signs are: 1-a top plate; 2-fixing the column; 3-external mold; 4-a bottom plate; 5-a foam buffer layer; 6-internal mold; 7-a through hole; 8-outer circumferential reinforcing ribs; 9-inner side circumferential reinforcing ribs; 10-positioning the supporting rod; 11-pouring a cavity; 12-a feed opening; 13-stirrup.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

As shown in fig. 1, the conventional secondary tunnel lining includes a concrete structure and reinforcing ribs inside, wherein the reinforcing ribs include an outer circumferential reinforcing rib 8, an inner circumferential reinforcing rib 9, and a stirrup 13 connected between the outer circumferential reinforcing rib 8 and the inner circumferential reinforcing rib 9; in the preparation of the secondary lining model, besides the concrete structure is prefabricated, how to implant corresponding reinforcing ribs into the model becomes a difficult problem.

As shown in fig. 2 to 5, the large-span tunnel lining model prefabricating device in the geomechanical model test of the invention comprises an inner mold 6, an outer mold 3, a bottom plate 4, a top plate 1 and a plurality of fixing columns 2, wherein the inner mold 6 and the outer mold 3 are arranged between the bottom plate 4 and the top plate 1, and a pouring cavity 11 of a tunnel secondary lining model is formed by utilizing the spaces among the inner mold 6, the outer mold 3, the bottom plate 4 and the top plate 1. The inner die 6 and the outer die 3 are formed by laminating a plurality of flat plates in the vertical direction, and each plate is divided into two symmetrical parts by the central line of the tunnel in the horizontal direction, so that the disassembly and the assembly are convenient. A plurality of through holes 7 are formed in the corresponding positions of the inner die 6, the outer die 3, the bottom plate 4 and the top plate 1, each through hole 7 corresponds to one fixing column 2, one part of the fixing columns 2 is used for fixing the inner die 6, the other part of the fixing columns 2 is used for fixing the outer die 3, and the fixing columns 2 penetrate through the through holes 7 to fix the prefabricated devices comprising the inner die 6, the outer die 3, the bottom plate 4 and the top plate 1 into a whole to form a spliced frame. Roof 1 and bottom plate 4 are all spliced in the top and the bottom of concatenation formula frame, and this concatenation formula frame can be according to the length demand in experimental tunnel through increasing the length of adjusting the lining cutting of the number of piles that reduces interior outer mould to satisfy the experimental requirement of different length tunnel models, each part of demolising moreover can also used repeatedly, avoids extravagant.

The plate is a PVC plate, an acrylic plate or a wood plate, and is tightly processed according to the set size by adopting a laser engraving machine, so that the size precision of the model is ensured. A plurality of feed openings 12 are formed in the top plate, and the feed openings 12 are a plurality of arc-shaped through grooves formed in the upper portion of the secondary lining model pouring cavity 11 and used for pouring concrete materials with similar linings for model pouring.

As shown in fig. 6, a foam buffer layer 5 is disposed on the outer side of the inner mold 6 for isolating the lining from the inner mold, facilitating the detachment of the inner mold, and supporting the reinforcing ribs inside the mold. As is known to all, a plurality of annular reinforcing steel bars are arranged inside the tunnel secondary lining, so a secondary lining model with the inside containing scaling steel bar parameters is required to be manufactured for testing in a model test, and how to implant the steel bars inside the model in the implementation becomes a difficult problem.

The invention adopts an ingenious method, a plurality of outer circumferential reinforcing ribs 8 and inner circumferential reinforcing ribs 9 are arranged in a cavity between an inner die 6 and an outer die 3, a plurality of positioning support rods 10 are arranged on a foam buffer layer 5, and the outer circumferential reinforcing ribs 8 and the inner circumferential reinforcing ribs 9 are fixed on the positioning support rods 10. As a preferable mode, the outer circumferential reinforcing rib 8, the inner circumferential reinforcing rib 9, and the positioning bar 10 are iron wires welded together. During implementation, insert the one end of a plurality of location iron wires at foam buffer layer 5 at the height of setting for earlier, then weld the iron wire of hoop on the location iron wire and fix, can also adjust the degree of depth of hoop iron wire in the model through the location iron wire of different length. So circulate, accomplish laying of a plurality of rings outside hoop strengthening rib 8 and inboard hoop strengthening rib 9, pour the concrete material into through feed opening 12 during pouring and pour cavity 11 in, the hoop iron wire is then pour the inside at the model with the location iron wire, and the diameter, the density and the pouring material of iron wire need be selected according to analogue test's requirement to ensure the accuracy and the representativeness of scaling test.

The invention realizes the preparation of the tunnel secondary lining model with the length of 30 cm-100 cm, the height of 36cm and the width of 54cm, wherein the thickness of the plate is 1.5cm, the thickness of the foam buffer layer is 1cm, and the diameter of the iron wire is 0.7 mm-1.2 mm. The foam buffer layer can be made of high-density rubber-plastic sponge, is arranged close to the inner side of the mold during installation, and reduces stress concentration on the building structure during mold stripping.

The method for preparing the tunnel secondary lining model by using the device comprises the following steps:

【1】 Preparing an article: scaling the cross section of a tunnel secondary lining model according to a certain proportion according to the requirements of a geomechanical model test, determining the size of a lining according to a similarity ratio principle, and preparing the bottom plate 4 and the top plate 1, and the plates of the splicing inner mold 6 and the outer mold 3 with corresponding sizes according to the scaled secondary lining model structure; the PVC board, the acrylic board or the wood board is cut into boards with proper sizes by a laser engraving machine, the bottom board only needs to be provided with a fixed column hole, the inner die and the outer die are opened with holes and the lining contour needs to be cut and molded, and the top board needs to be provided with a fixed column hole and a large hole for pouring lining similar materials.

【2】 Inner die splicing: arranging a bottom plate 4 at the bottom of the device, inserting a fixed column 2 into a through hole at a position corresponding to an inner mold 6 on the bottom plate 4, and splicing the inner mold 6 to a set height; or the bottom plate can be arranged at the bottom, the internal mold is assembled to a certain height, and the position is fixed by a fixing column.

【3】 And (3) laying the circumferential reinforcing ribs: winding the foam buffer layer 5 on the outer side of the inner die 6, and inserting one end of the positioning support rod 10 into the foam buffer layer 5; arranging an outer side circumferential reinforcing rib 8 and an inner side circumferential reinforcing rib 9 in the secondary lining model pouring cavity 11, so that the circumferential reinforcing ribs are fixed at the outer leakage end of the positioning support rod 10; specifically, the outer circumferential reinforcing rib 8, the inner circumferential reinforcing rib 9 and the positioning support rod 10 are made of iron wires, one end of each positioning iron wire is inserted into the foam buffer layer 5 according to a set height, and then the circumferential iron wires are welded at one leaking end of each positioning iron wire;

【4】 Outer mold splicing: splicing the outer mold 3 to a set height, inserting the fixing columns 2 corresponding to the outer mold 3, and installing the top plate 1 to enable the prefabricating device to be fixed into a whole;

【5】 Pouring: pouring lining materials with a certain mixing proportion into the prefabricated cavity through the feed opening 12, and standing for a set time; according to the test requirements and the mixing proportion of similar materials, pouring the uniformly stirred similar materials into a mold, and generally standing for 24 hours.

【6】 Removing the mold: and (3) removing the top plate 1, the inner mold 6, the outer mold 3 and the fixing column 2 layer by layer, and removing the foam buffer layer 5 to obtain the secondary lining model. Removing the redundant lining similar materials on the upper parts of the inner and outer side moulds, then removing the inner side mould and the foam buffer layer, and removing the outer mould after the lining reaches certain strength. The disassembly sequence is that the inner mold is disassembled firstly, and then the outer mold is disassembled; when the inner mold and the outer mold are disassembled, the fixing columns are pulled out first, and then the plates of the inner mold and the outer mold are sequentially disassembled.

When the prepared secondary lining model is subjected to a geomechanical model test, after the surrounding rock similar material is buried to a certain height, the prefabricated tunnel lining is buried, the surrounding rock material is continuously buried to a certain height, and subsequent work such as load application, deformation, stress monitoring and the like is carried out according to test requirements.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (9)

1. The utility model provides a large-span tunnel lining model prefabricating device in geomechanical model test which characterized in that: the inner mold (6) and the outer mold (3) are arranged between the bottom plate (4) and the top plate (1) and form a pouring cavity (11) of a secondary lining model; the inner die (6) and the outer die (3) are formed by laminating a plurality of flat plates in the vertical direction, and each plate is split into two halves in the horizontal direction; the inner die (6), the outer die (3), the bottom plate (4) and the top plate (1) are provided with a plurality of through holes (7) at corresponding positions, and the fixing column (2) penetrates through the through holes (7) to fix the prefabricating device into a whole; the top plate is provided with a plurality of feed openings (12).

2. The prefabricating device for the large-span tunnel lining model in the geomechanical model test, according to claim 1, is characterized in that: and a foam buffer layer (5) is arranged on the outer side of the inner die (6).

3. The prefabricating device for the large-span tunnel lining model in the geomechanical model test, according to claim 2, is characterized in that: a plurality of outer circumferential reinforcing ribs (8) and inner circumferential reinforcing ribs (9) are arranged in a cavity between the inner die (6) and the outer die (3), a plurality of positioning support rods (9) are arranged on the foam buffer layer (5), and the outer circumferential reinforcing ribs (8) and the inner circumferential reinforcing ribs (9) are fixed on the positioning support rods (9).

4. The prefabricating device for the large-span tunnel lining model in the geomechanical model test, according to claim 3, is characterized in that: the outer circumferential reinforcing rib (8), the inner circumferential reinforcing rib (9) and the positioning support rod (9) are iron wires welded together.

5. The prefabricating device for the large-span tunnel lining model in the geomechanical model test, according to claim 1, is characterized in that: the feed opening is a plurality of arc-shaped through grooves arranged at the upper part of the secondary lining model pouring cavity (11).

6. The prefabricating device for the large-span tunnel lining model in the geomechanical model test, according to claim 1, is characterized in that: the board is a PVC board, an acrylic board or a wood board.

7. The method for prefabricating the lining model by using the large-span tunnel lining model prefabricating device in the geomechanical model test, as claimed in any one of claims 1 to 6, is characterized by comprising the following steps:

【1】 Preparing an article: scaling the cross section of the tunnel secondary lining model according to a certain proportion according to the requirements of a geomechanical model test, and preparing the bottom plate (4) and the top plate (1) with corresponding sizes and plates for splicing the inner mold (6) and the outer mold (3) according to the scaled secondary lining model structure;

【2】 Inner die splicing: inserting a fixed column (2) into a through hole at a position corresponding to the inner mold (6) on the bottom plate (4), and splicing the inner mold (6) to a set height;

【3】 And (3) laying the circumferential reinforcing ribs: winding the foam buffer layer (5) on the outer side of the inner die (6), and inserting one end of the positioning support rod (10) into the foam buffer layer (5); an outer side circumferential reinforcing rib (8) and an inner side circumferential reinforcing rib (9) are arranged in the secondary lining model pouring cavity (11) in a distributed mode, so that the outer side circumferential reinforcing rib (8) and the inner side circumferential reinforcing rib (9) are fixed at the outer leakage end of the positioning support rod (10);

【4】 Outer mold splicing: splicing the outer die (3) to a set height, inserting the fixing column (2) corresponding to the outer die (3), and installing the top plate (1) to fix the prefabricated device into a whole;

【5】 Pouring: pouring lining materials with a certain mixing proportion into the prefabricated cavity through a feed opening (12), and standing for a set time;

【6】 Removing the mold: and (3) removing the top plate (1), the inner mold (6), the outer mold (3) and the fixing column (2) layer by layer, and removing the foam buffer layer (5) to obtain the secondary lining model.

8. The prefabrication method of the large-span tunnel lining model in the geomechanical model test, according to claim 7, is characterized in that: and (5) standing for 24 hours.

9. The prefabrication method of the large-span tunnel lining model in the geomechanical model test, according to claim 7, is characterized in that: the dismantling sequence in the step (6) is that the inner mold is dismantled firstly, and then the outer mold is dismantled; when the inner mold and the outer mold are disassembled, the fixing columns are pulled out first, and then the plates of the inner mold and the outer mold are sequentially disassembled.

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