A precast formwork system for a dampproof wall

Abstract

This utility model relates to the field of tunnel construction technology, specifically to a precast template system for a grout-stopping wall. The precast template system includes a first precast template assembly, which includes a first precast template and an orifice pipe. Several positioning holes are correspondingly opened at several preset positions on the first precast template. The positioning holes are opened at preset angles and penetrate the first precast template. The orifice pipe passes through the positioning holes at preset angles and extends into the pouring space of the grout-stopping wall. One end of the orifice pipe connected to the first precast template is connected to a flange, and the orifice pipe and the first precast template are detachably connected through the flange. This utility model can precast the grout-stopping wall template and pre-install the orifice pipe on the template. The orifice pipe can be installed in place at one time with the pouring of the grout-stopping wall, saving construction steps, improving construction efficiency, and improving the positioning accuracy of the positioning holes of the precast template, thus ensuring the subsequent grouting effect.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction technology, and in particular to a prefabricated template system for grout-stopping walls. Background Technology

[0002] When constructing tunnels in areas with poor geological conditions and soft strata, grouting is required before excavation to stabilize the surrounding rock structure and prevent tunnel collapse due to overlying rock subsidence. This is a common method in tunnel construction known as curtain grouting. Before curtain grouting, a grout stop wall needs to be constructed at the tunnel face to prevent backflow and leakage of the high-pressure grout injected into the surrounding rock. Before pouring the grout stop wall, a formwork needs to be erected in front of the tunnel face to create a pouring space between the formwork and the tunnel face. After the grout stop wall is poured, holes are drilled at predetermined positions on the formwork to form grouting holes that penetrate the grout stop wall into the surrounding rock of the tunnel. This allows for the subsequent installation of grouting pipes in the grouting holes for grouting operations. After drilling, grout is then poured onto the formwork. A borehole pipe is installed at the opening of the grouting hole to guide the grouting pipe into the hole. However, this method of drilling holes and placing the borehole pipe after the grout stop wall is poured requires manual marking and positioning on the construction site throughout the process. This may lead to inaccurate drilling positions and make it difficult to accurately measure and control the drilling angle. Since the grouting holes are quite deep, the drilling depth of the grouting holes behind the grout stop wall can reach tens of meters or even more. Even a small deviation in the drilling position and angle on the formwork can lead to a large deviation in the subsequent grouting position, which can easily affect the grouting effect. In addition, drilling holes on-site and then installing the borehole pipe will increase the construction steps and reduce construction efficiency. Drilling holes on the grout stop wall after it has been poured can also easily cause cracks in the concrete structure in the non-hole areas, resulting in structural instability. Utility Model Content

[0003] The purpose of this invention is to overcome the technical problems of existing technologies that require manual marking and positioning on the construction site to drill holes in the grout stop wall template when performing curtain grouting in tunnels. This increases the on-site installation steps of the borehole pipe, resulting in low construction efficiency and is also prone to deviations in drilling position and angle, which in turn increases the deviation in the subsequent grouting position. The invention provides a prefabricated template system for grout stop walls.

[0004] In a first aspect, this utility model provides a precast template system for a grout-stopping wall, comprising a first precast template assembly, the first precast template assembly including a first precast template and an orifice pipe, a plurality of positioning holes being correspondingly opened at a plurality of preset positions on the first precast template, the positioning holes being opened at a preset angle and penetrating the first precast template, the orifice pipe passing through the positioning holes at the preset angle and extending into the pouring space of the grout-stopping wall, a flange being connected to one end of the orifice pipe connected to the first precast template, and the orifice pipe being detachably connected to the first precast template through the flange.

[0005] This invention solves the aforementioned technical problems by prefabricating the grout-stopping wall template. Specifically, before the grout-stopping wall construction, the opening positions of the grouting holes can be determined on the prefabricated template, and positioning holes can be reserved at the preset positions of the grouting holes. The opening angle of the grouting holes can also be determined, and the positioning holes are opened at the preset angle of the grouting holes. That is to say, the opening position and angle of the grouting holes can be determined simultaneously through the opening positioning holes, and the orifice pipe is installed in the corresponding positioning holes, so that the position and angle of the orifice pipe are consistent with the positioning holes, that is, consistent with the preset position and preset angle of the grouting holes. One end of the orifice pipe can be detachably connected to the prefabricated template through a flange, and the other end can extend to the side of the prefabricated template facing the working face and be placed during the pouring of the grout-stopping wall. In this space, when the grout-stopping wall is being poured, the injection head can be inserted into the orifice pipe for grouting. After the pouring is completed, the grout-stopping wall will naturally form the front opening of the grouting hole at the position of the orifice pipe. The orifice pipe is also pre-embedded in the grout-stopping wall. There is no need to carry out additional construction steps of positioning drilling and then installing the orifice pipe after the grout-stopping wall is poured. The orifice pipe can be installed in place at one time with the pouring of the grout-stopping wall, saving construction steps and improving construction efficiency. In addition, the positioning holes on the prefabricated template can be precisely positioned by machine during the production process, and the angle determination can also ensure sufficient accuracy. Compared with the method of drilling and positioning by manually marking lines on the construction site, the positioning accuracy of the positioning holes of the prefabricated template of this utility model can also be improved, ensuring the subsequent grouting effect.

[0006] Preferably, the orifice pipe is a tapered pipe, and the outer diameter of the end of the orifice pipe that extends into the casting space is smaller than the outer diameter of the connection end between the orifice pipe and the first precast template.

[0007] When the connection between the orifice pipe and the flange is non-removable, such as when the orifice pipe and the flange are integrally formed, the orifice pipe and the flange need to be disassembled together after the grout stop wall is poured, and then the formwork needs to be removed. After the formwork is removed, the orifice pipe is reinstalled and reset onto the grout stop wall. To facilitate the disassembly of the orifice pipe, its shape can be designed as a tapered structure, making it easier to separate from the concrete of the grout stop wall during disassembly and reducing the friction between the orifice pipe and the concrete during disassembly and movement. Alternatively, the orifice pipe and the flange can be detachably connected, for example, by threaded connection. In this way, after the grout stop wall is poured, only the flange needs to be removed, and then the formwork can be removed from the orifice pipe to complete the demolding, without removing the orifice pipe itself. This allows the orifice pipe to remain on the grout stop wall, eliminating the steps of disassembling and reinstalling the orifice pipe, and further improving construction efficiency. Of course, regardless of whether the orifice pipe and the flange are detachably connected, the construction efficiency is improved compared to the existing technology of positioning and drilling on the construction site, at least eliminating the steps of on-site positioning and drilling.

[0008] Preferably, the first prefabricated template includes a plurality of first sub-templates that are spliced ​​together.

[0009] The first precast template adopts a multi-piece sub-template assembly structure, which allows each sub-template to be demolded in a certain order after pouring. Especially for the case where the above-mentioned orifice pipe and flange are detachably connected, since the angle of each orifice pipe relative to the template is different, if the overall demolding is used, interference will inevitably occur between the orifice pipe and the template, making demolding impossible. However, using spliced ​​sub-templates for segmented demolding can solve this problem. Specifically, the sub-templates without positioning holes can be demolded first, and then the sub-templates with orifice pipes can be demolded along the setting direction of the orifice pipes, thus finally achieving the demolding of the first precast template.

[0010] Preferably, the first prefabricated template assembly further includes a plurality of transverse fixing rods and a plurality of longitudinal fixing rods, wherein the transverse fixing rods are connected between the plurality of transversely spliced ​​first sub-templates, and the longitudinal fixing rods are connected between two adjacent longitudinally spliced ​​first sub-templates.

[0011] When assembling the first precast template, multiple horizontal and vertical fixing rods can be used to splice the various first sub-templates. Specifically, the horizontal and vertical fixing rods can be welded to the first sub-templates for connection. The assembly process can also be prefabricated in the factory, and the assembled first precast template can be directly installed in place on the construction site. Of course, depending on the situation, the various first sub-templates can also be assembled on the construction site. When demolding after the grout stop wall is poured, the horizontal and vertical fixing rods can be cut and removed first, and then the various first sub-templates can be demolded separately.

[0012] Preferably, it further includes a second precast template, which includes a plurality of second sub-templates spliced ​​together, and the plurality of second sub-templates surround the first precast template in the circumferential direction of the tunnel.

[0013] Preferably, a telescopic mechanism is connected between the second sub-template and the first precast template. The telescopic mechanism can drive the second precast template to expand radially along the tunnel and fit tightly against the inner wall surface formed by the tunnel excavation.

[0014] The shape and inner diameter of the inner wall formed by tunnel excavation are usually different. For a first precast template with a fixed size, its outer diameter is generally slightly smaller than the inner diameter of the tunnel excavation face. A gap will appear between the inner wall of the tunnel and the first precast template, which will not be able to form a sufficient seal for the pouring space of the grout stop wall, resulting in grout leakage during the pouring of the grout stop wall. Therefore, a second sub-template needs to be added to the gap between the inner wall of the tunnel and the first precast template to seal the gap and avoid grout leakage during pouring. The second sub-template can be expanded or contracted radially by a telescopic mechanism to adapt to tunnels with different inner diameters. Of course, after the second sub-template expands, a gap will also appear between the second sub-template and the first precast template. This gap needs to be sealed on-site with sealing material.

[0015] Preferably, the telescopic mechanism includes a hydraulic cylinder.

[0016] Preferably, the material of the second sub-template includes a polymer material.

[0017] The material for the second sub-template can be a polymer material with good sealing properties, such as plastic.

[0018] Preferably, the orifice pipe and the flange are integrally connected; or, the orifice pipe and the flange are detachably connected by a threaded connection.

[0019] Preferably, the first prefabricated template is a steel template.

[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0021] This utility model provides a prefabricated template system for grout-stopping walls. By prefabricating the grout-stopping wall template, the aforementioned technical problems are solved. Specifically, before the construction of the grout-stopping wall, the opening positions of the grouting holes can be determined on the prefabricated template, and positioning holes are reserved at the preset positions of the grouting holes. The opening angle of the grouting holes can also be determined, and the positioning holes are opened at the preset angle of the grouting holes. That is, the opening position and angle of the grouting holes can be determined simultaneously through the positioning holes, and the orifice pipe is installed correspondingly in the positioning holes, so that the position and angle of the orifice pipe are consistent with the positioning holes, that is, consistent with the preset position and preset angle of the grouting holes. One end of the orifice pipe can be detachably connected to the prefabricated template through a flange, and the other end can extend to the side of the prefabricated template facing the working face and be placed... In the pouring space of the grout-stopping wall, when the grout-stopping wall is being poured, the injection head can be inserted into the orifice pipe for grouting. After the pouring is completed, the grout-stopping wall will naturally form the front opening of the grouting hole at the position of the orifice pipe. The orifice pipe is also pre-embedded in the grout-stopping wall. There is no need to carry out the construction steps of drilling positioning holes and installing orifice pipes after the grout-stopping wall is poured. The orifice pipe can be installed in place at one time with the pouring of the grout-stopping wall, saving construction steps and improving construction efficiency. In addition, the positioning holes on the prefabricated template can be precisely positioned by machine during the production process, and the angle determination can also ensure sufficient accuracy. Compared with the method of drilling and positioning by manually marking lines on the construction site, the positioning accuracy of the positioning holes of the prefabricated template of this utility model can also be improved, ensuring the subsequent grouting effect. Attached Figure Description

[0022] Figure 1 This is a structural schematic diagram of the prefabricated formwork system for the grout-stopping wall of this utility model.

[0023] Figure 2 This is a partial cross-sectional schematic diagram of the first precast template (with hidden orifice pipe).

[0024] Figure 3 This is a schematic diagram showing the installation of the orifice pipe on the first precast template (showing the orifice pipe).

[0025] Figure 4 This is a schematic diagram of the installation of the tapered orifice pipe on the first precast template.

[0026] Figure 5 for Figure 1 A magnified view of a portion of point A in the middle.

[0027] Marked in the image:

[0028] 1. First precast template; 11. First sub-template; 111. Positioning hole; 2. Orifice pipe; 3. Flange; 4. Horizontal fixing tie rod; 5. Longitudinal fixing tie rod; 6. Second precast template; 61. Second sub-template; 7. Telescopic mechanism. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments. However, it should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0030] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of this utility model is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the utility model solution or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on this utility model.

[0031] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0032] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0033] Furthermore, in the description of the embodiments of this utility model, "several", "multiple", and "several" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0034] Furthermore, in the description of the technical solution of this utility model, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "equipped with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0035] Example

[0036] This embodiment provides a prefabricated formwork system for grout-stopping walls.

[0037] Figure 1 This is a structural schematic diagram of the prefabricated formwork system for the grout-stopping wall of this utility model; Figure 2 This is a partial cross-sectional schematic diagram of the first precast template (with hidden orifice pipe); Figure 3 This is a schematic diagram showing the installation of the orifice pipe on the first precast template (showing the orifice pipe). Figure 4 This is a schematic diagram showing the installation of the tapered orifice pipe on the first precast template. Figure 5 for Figure 1 A magnified view of a portion of point A in the middle.

[0038] like Figures 1 to 5 As shown in the figure, the precast template system for the grout-stopping wall in this embodiment includes a first precast template assembly, which includes a first precast template 1 and an orifice pipe 2. Multiple positioning holes 111 are correspondingly opened at multiple preset positions on the first precast template 1. The positioning holes 111 are opened at a preset angle and penetrate the first precast template 1. The orifice pipe 2 passes through the positioning holes 111 at a preset angle and extends into the pouring space of the grout-stopping wall. A flange 3 is connected to one end of the orifice pipe 2 connected to the first precast template 1, and the orifice pipe 2 and the first precast template 1 are detachably connected via the flange 3. Here, the multiple preset positions on the first precast template 1 correspond to grouting. The positions of the holes, namely the grouting hole, the positioning hole 111, and the orifice pipe 2, coincide. The preset angle of the positioning hole 111 is also consistent with the opening angle of the grouting hole and the setting angle of the orifice pipe 2. The flange 3 can be connected to the first precast template 1 by bolts. When removing the flange 3, the bolts need to be loosened and removed first to disconnect the flange 3 from the first precast template 1. Then the flange 3 can be removed from the first precast template 1. The orifice pipe 2 and the flange 3 can be connected as a single piece. In addition, the orifice pipe 2 and the flange 3 can also be connected by detachable connection methods such as threaded connection.

[0039] This invention solves the aforementioned technical problems by prefabricating the grout-stopping wall template. Specifically, before the grout-stopping wall construction, the opening positions of the grouting holes can be determined on the prefabricated template, and positioning holes 111 can be reserved at the preset positions of the grouting holes. The opening angle of the grouting holes can also be determined, and the positioning holes 111 are opened at the preset angle of the grouting holes. That is to say, the opening position and angle of the grouting holes can be determined simultaneously through the opening positioning holes 111, and the orifice pipe 2 is installed in the corresponding positioning holes 111, so that the position and angle of the orifice pipe 2 are consistent with the positioning holes 111, that is, consistent with the preset position and preset angle of the grouting holes. One end of the orifice pipe 2 can be detachably connected to the prefabricated template through the flange 3, and the other end can extend to the side of the prefabricated template facing the working face and be placed in the grout-stopping wall. In the pouring space of the wall, when the grout-stopping wall is being poured, the injection head can be inserted into the orifice pipe 2 for grouting. After the pouring is completed, the grout-stopping wall will naturally form the front opening of the grouting hole at the position of the orifice pipe 2. The orifice pipe 2 is also pre-embedded in the grout-stopping wall. There is no need to carry out the construction steps of drilling positioning holes and installing the orifice pipe 2 after the grout-stopping wall is poured. The orifice pipe 2 can be installed in place at one time with the pouring of the grout-stopping wall, saving construction steps and improving construction efficiency. In addition, the positioning holes 111 on the prefabricated template can be precisely positioned by machine during the production process, and the angle determination can also ensure sufficient accuracy. Compared with the method of drilling and positioning by manually marking lines on the construction site, the positioning accuracy of the positioning holes 111 of the prefabricated template of this utility model can also be improved, ensuring the subsequent grouting effect.

[0040] In this embodiment, the orifice pipe 2 can be a tapered pipe, and the outer diameter of the end of the orifice pipe 2 that extends into the casting space is smaller than the outer diameter of the connection end between the orifice pipe 2 and the first precast template 1.

[0041] When the connection between the orifice pipe 2 and the flange 3 is non-removable, such as when the orifice pipe 2 and the flange 3 are integrally formed, the orifice pipe 2 and the flange 3 need to be disassembled together after the grout stop wall is poured, followed by the removal of the formwork. After the formwork is removed, the orifice pipe 2 is then reinstalled onto the grout stop wall. To facilitate the disassembly of the orifice pipe 2, its shape can be designed as a tapered structure, with the outer diameter of the end of the orifice pipe 2 extending into the pouring space being smaller than the outer diameter of the connection end between the orifice pipe 2 and the first precast formwork 1. In other words, the outer diameter of the orifice pipe 2 gradually decreases along the direction it extends into the pouring space. This makes it easier to separate the orifice pipe 2 from the concrete of the grout stop wall during disassembly, reducing the friction between the orifice pipe 2 and the concrete during disassembly and movement. Of course, the connection between the orifice pipe 2 and the flange 3 can also be detachable. For example, by using a threaded connection, after the grout stop wall is poured, only the flange 3 needs to be removed, and then the formwork can be removed from the orifice pipe 2 to complete the demolding. There is no need to remove the orifice pipe 2, so that the orifice pipe 2 can always remain on the grout stop wall. This eliminates the steps of disassembling and reinstalling the orifice pipe 2, which can further improve construction efficiency. Of course, regardless of whether the orifice pipe 2 and the flange 3 are detachable, the construction efficiency can be improved compared to the existing technology of positioning and drilling on the construction site. At least the steps of on-site positioning and drilling can be eliminated.

[0042] In this embodiment, the first prefabricated template 1 includes multiple first sub-templates 11 spliced ​​together.

[0043] The first precast template 1 adopts an assembly structure of multiple first sub-templates 11. This allows for the demolding of each first sub-template 11 in a specific order after casting. This is particularly useful in cases where the orifice pipe 2 and flange 3 are detachably connected. Since each orifice pipe 2 has a different angle relative to the template, overall demolding would inevitably cause interference between the orifice pipe 2 and the template, making demolding impossible. However, using the assembled first sub-templates 11 for segmented demolding solves this problem. Specifically, the first sub-template 11 without positioning holes 111 can be demolded first, and then the first sub-template 11 with orifice pipes 2 can be demolded separately along the orifice pipes 2. By setting the direction for demolding, the first precast template 1 can be demolded. If all the first sub-templates 11 have positioning holes 111, the first sub-template 11 located in the middle of the first precast template 1 can be demolded first. Because the positioning holes 111 on the first sub-template 11 located in the middle have a smaller inclination angle, the interference between the first sub-template 11 and the orifice tube 2 is not obvious, and demolding is easier. After the first sub-template 11 located in the middle is demolded first, space can be reserved for the movement of other adjacent first sub-templates 11, and the first sub-templates 11 in other positions can be demolded. Finally, the entire first precast template 1 can be demolded.

[0044] Alternatively, the first precast template assembly may also include multiple transverse fixing rods 4 and multiple longitudinal fixing rods 5. The transverse fixing rods 4 are connected between multiple transversely spliced ​​first sub-templates 11, and the longitudinal fixing rods 5 are connected between two adjacent longitudinally spliced ​​first sub-templates 11.

[0045] When assembling the first precast template 1, multiple horizontal and vertical fixing rods can be used to splice the various first sub-templates 11. Specifically, the horizontal fixing rod 4 and the vertical fixing rod 5 can be welded to the first sub-template 11 for connection. The assembly process can also be prefabricated in the factory, and the assembled first precast template 1 can be directly installed in place on the construction site. Of course, the various first sub-templates 11 can also be assembled on the construction site as needed. When demolding after the grout stop wall is poured, the horizontal fixing rod 4 and the vertical fixing rod 5 can be cut and removed first, and then the various first sub-templates 11 can be demolded separately.

[0046] In addition to using the horizontal fixing rod 4 and the vertical fixing rod 5, other methods can also be used to assemble the various first sub-templates 11. For example, the various first sub-templates 11 can be directly welded together. Spot welding can be used to facilitate cutting and separating the various first sub-templates 11 during demolding, so as to avoid excessive cutting work during demolding caused by continuous welds. This utility model does not specify the connection method between the various first sub-templates 11.

[0047] In this embodiment, the prefabricated template system for the grout-stopping wall also includes a second prefabricated template 6. The second prefabricated template 6 includes multiple second sub-templates 61 spliced ​​together, and the multiple second sub-templates 61 surround the first prefabricated template 1 along the circumference of the tunnel.

[0048] Optionally, a telescopic mechanism 7 is connected between the second sub-formwork 61 and the first precast formwork 1. The telescopic mechanism 7 can drive the second precast formwork 6 to expand radially along the tunnel and fit tightly against the inner wall surface formed by the tunnel excavation. Here, the telescopic mechanism 7 can be a cylinder, hydraulic cylinder, push rod, or screw, etc. Of course, the second sub-formwork 61 and the first precast formwork 1 can also be connected by a fixed connection method such as a fixed tie rod, which can replace the telescopic mechanism 7. In this case, the second sub-formwork 61 does not have a telescopic function. If a gap appears between the second sub-formwork 61 and the inner wall surface of the tunnel during installation, it is necessary to use sealing material to seal the gap between the second sub-formwork 61 and the inner wall surface of the tunnel to prevent leakage.

[0049] The shape and inner diameter of the inner wall formed by tunnel excavation are usually different. For the first precast template 1 with a fixed size, its outer diameter is generally slightly smaller than the inner diameter of the tunnel excavation face. A gap will appear between the inner wall of the tunnel and the first precast template 1, which will not be able to form a sufficient seal for the pouring space of the grout stop wall, resulting in grout leakage during the pouring of the grout stop wall. Therefore, a second sub-template 61 needs to be added to the gap between the inner wall of the tunnel and the first precast template 1 to seal the gap and avoid grout leakage during pouring. The second precast template 6 can be expanded or contracted radially by the telescopic mechanism 7 to adapt to tunnels with different inner diameters. Of course, after the second precast template 6 expands, gaps may appear between adjacent second sub-templates 61, and gaps may also appear between the second precast template 6 and the first precast template 1. All gaps caused by the expansion of the second precast template 6 need to be sealed on-site using sealing materials.

[0050] It should be noted that, in order to ensure that the second precast template 6 equipped with the telescopic mechanism 7 can realize the function of radial expansion and contraction, the second sub-templates 61 in the second precast template 6 are not connected to each other. The second sub-templates 61 are only connected to the first precast template 1 through the telescopic mechanism 7. This allows the second sub-templates 6 to naturally separate or close together during the contraction and expansion process.

[0051] Alternatively, the material of the second sub-template 61 may include a polymer material.

[0052] The material for the second sub-template 61 can be a polymer material with good sealing performance, such as plastic.

[0053] The first precast formwork 1 can be made of steel. Compared with traditional wooden formwork, steel formwork has higher strength, better flatness, and greater stability. In addition, steel formwork is not easily damaged during demolding and has a higher reuse rate, while traditional wooden formwork is easily damaged during demolding, resulting in a low reuse rate.

[0054] The following describes in detail the method of using the precast formwork system for the grout-stopping wall in this embodiment. The method of use includes the following steps:

[0055] S1: Pre-install the orifice pipe 2 corresponding to the positioning hole 111 on the first prefabricated template 1, assemble the first prefabricated template 1, and install the first prefabricated template 1 in place at the construction site to ensure that the other end of the orifice pipe 2 relative to the flange 3 faces the working face.

[0056] S2: Concrete is poured into the pouring space of the grout-stopping wall to construct the grout-stopping wall;

[0057] S3: After the concrete has initially set, disconnect the connection between flange 3 and the first precast template 1. If the connection between flange 3 and orifice pipe 2 is detachable, then remove flange 3.

[0058] S4: Remove the first precast template 1 and leave the orifice pipe 2 in the grout stop wall, and then carry out the curtain grouting operation.

[0059] In step S1 above, if the first precast template 1 is assembled from multiple first sub-templates 11, then the multiple first sub-templates 11 need to be assembled to form the first precast template 1. The assembly process can be prefabricated in the factory or carried out on the construction site as appropriate. The order of installing the orifice pipe 2 and assembling to form the first precast template 1 in step S1 can be changed.

[0060] In step S2 above, the injection head of the grouting equipment can be inserted into the orifice pipe 2 for concrete pouring. It is necessary to select an injection head that matches the inner cavity of the orifice pipe 2. After the injection head is inserted into the orifice pipe 2, the inner cavity of the orifice pipe 2 can be completely filled and sealed. After the pouring is completed, it can prevent concrete from entering the orifice pipe 2 and leaking. It is also beneficial to the pouring and forming of the front opening of the grouting hole.

[0061] Of course, for multiple orifice pipes 2, a portion of orifice pipes 2 can be selected for grouting and pouring of the grout-stopping wall, while the remaining orifice pipes 2 that have not been grouted need to be sealed by filling the inner cavity of the orifice pipes 2 with plugs. This can prevent the poured concrete from entering the orifice pipes 2 and leaking out, and can also facilitate the pouring and forming of the front opening of the grouting hole. After the pouring is completed and the concrete has initially set, the injection head or plug filled in the orifice pipes 2 can be removed.

[0062] If the flange 3 and the orifice pipe 2 are connected as a single unit, then step S3 is replaced by S3' and step S4 is replaced by S4'.

[0063] S3': After the concrete has initially set, disconnect the connection between flange 3 and the first precast template 1, and remove flange 3 and orifice pipe 2.

[0064] S4': Remove the first precast template 1, then reposition the orifice pipe 2 into the grout-stopping wall, and then carry out the curtain grouting operation.

[0065] In step S4' above, when resetting the orifice pipe 2, first apply sealing grout to the outer wall of the orifice pipe 2, and then reset the orifice pipe 2 into the grout-stopping wall.

[0066] Since the flange 3 and orifice pipe 2, which adopt an integrated structure, need to be removed before demolding, there will be a process of resetting after demolding. During the resetting process, the concrete of the grout-stopping wall has already solidified. After resetting, gaps may easily appear between the outer wall of the orifice pipe 2 and the concrete of the grout-stopping wall, reducing the sealing performance. This may affect the grout-stopping effect of the grout-stopping wall in subsequent curtain grouting operations. Therefore, a layer of sealing grout can be applied to the outer wall of the orifice pipe 2 before resetting. The sealing grout can enhance the sealing performance between the outer wall of the orifice pipe 2 and the concrete of the grout-stopping wall.

[0067] In summary, this utility model provides a prefabricated template system for grout-stopping walls. By prefabricating the grout-stopping wall template, the aforementioned technical problems are solved. Specifically, before the construction of the grout-stopping wall, the location of the grouting holes can be determined on the prefabricated template, and positioning holes can be reserved at the preset locations of the grouting holes. The opening angle of the grouting holes can also be determined, and the positioning holes are opened at the preset angle of the grouting holes. That is, the opening position and angle of the grouting holes can be simultaneously determined through the positioning holes, and the orifice pipe is installed correspondingly in the positioning holes, so that the position and angle of the orifice pipe are consistent with the positioning holes, i.e., consistent with the preset position and preset angle of the grouting holes. One end of the orifice pipe can be detachably connected to the prefabricated template via a flange, and the other end can extend to the prefabricated template facing the working face. The grouting pipe is placed side by side in the pouring space of the grout-stopping wall. When the grout-stopping wall is being poured, the injection head can be inserted into the orifice pipe for grouting. After the pouring is completed, the grout-stopping wall will naturally form the front opening of the grouting hole at the position of the orifice pipe. The orifice pipe is also pre-embedded in the grout-stopping wall. There is no need to carry out the construction steps of drilling positioning holes and installing orifice pipes after the grout-stopping wall is poured. The orifice pipe can be installed in place at one time with the pouring of the grout-stopping wall, saving construction steps and improving construction efficiency. In addition, the positioning holes on the prefabricated template can be precisely positioned by machine during the production process, and the angle determination can also ensure sufficient accuracy. Compared with the method of drilling and positioning by manually marking lines on the construction site, the positioning accuracy of the positioning holes of the prefabricated template of this utility model can also be improved, ensuring the subsequent grouting effect.

[0068] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A prefabricated formwork system for grout-stopping walls, characterized in that, The first precast template assembly includes a first precast template (1) and an orifice pipe (2). A plurality of positioning holes (111) are opened at a plurality of preset positions on the first precast template (1). The positioning holes (111) are opened at a preset angle and penetrate the first precast template (1). The orifice pipe (2) passes through the positioning holes (111) at the preset angle and extends into the pouring space of the grout stop wall. A flange (3) is connected to one end of the orifice pipe (2) connected to the first precast template (1). The orifice pipe (2) and the first precast template (1) are detachably connected through the flange (3). The first prefabricated template (1) includes several first sub-templates (11) spliced ​​together; the first prefabricated template assembly also includes several horizontal fixing rods (4) and several vertical fixing rods (5), the horizontal fixing rods (4) are connected between several horizontally spliced ​​first sub-templates (11), and the vertical fixing rods (5) are connected between two adjacent vertically spliced ​​first sub-templates (11).

2. The prefabricated formwork system for grout-stopping walls according to claim 1, characterized in that, The orifice pipe (2) is a tapered pipe, and the outer diameter of the end of the orifice pipe (2) that extends into the casting space is smaller than the outer diameter of the connection end between the orifice pipe (2) and the first precast template (1).

3. The precast formwork system for grout-stopping walls according to claim 1, characterized in that, It also includes a second precast template (6), which includes several second sub-templates (61) spliced ​​together, and the several second sub-templates (61) surround the first precast template (1) in the circumferential direction of the tunnel.

4. The precast formwork system for grout-stopping walls according to claim 3, characterized in that, The second sub-template (61) is connected to the first precast template (1) by a telescopic mechanism (7). The telescopic mechanism (7) can drive the second precast template (6) to expand radially along the tunnel and fit tightly against the inner wall surface formed by the tunnel excavation.

5. The precast formwork system for grout-stopping walls according to claim 4, characterized in that, The telescopic mechanism (7) includes a hydraulic cylinder.

6. The precast formwork system for grout-stopping walls according to any one of claims 3 to 5, characterized in that, The material of the second sub-template (61) includes polymer materials.

7. The precast formwork system for grout-stopping walls according to claim 1, characterized in that, The orifice pipe (2) and the flange (3) are integrally connected; or the orifice pipe (2) and the flange (3) are detachably connected by threaded connection.

8. The precast formwork system for grout-stopping walls according to claim 1, characterized in that, The first precast template (1) is a steel template.

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