Method for embedding grouting pipe in tunnel lining concrete

Abstract

The application provides a method for embedding a grouting pipe in tunnel lining concrete, and relates to the technical field of tunnel construction. The method comprises the following steps: passing the grouting pipe through a reserved hole of a lining trolley, so that one end of the grouting pipe abuts against a preset position of tunnel surrounding rock; the end of the grouting pipe abutting against the tunnel surrounding rock is blocked, and the pipe body of the grouting pipe is processed with a plurality of grouting holes; a buffer layer is wrapped outside the grouting pipe; the buffer layer comprises an outer layer made of a positive Poisson's ratio material and an inner layer made of a negative Poisson's ratio material in sequence, the outer layer and the inner layer are fixed through a plurality of point connections, and the buffer layer is processed with a through hole penetrating through the inner layer and the outer layer; the grouting pipe is fixed on a steel support through wire tying; concrete is poured between the table surface of the lining trolley and the tunnel surrounding rock, and the embedding of the grouting pipe is completed after the concrete is cured and cemented. The application can reduce the vibration or impact on the grouting pipe, and make the grouting pipe more stable during the lining concrete process.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a method for pre-embedding grouting pipes in tunnel lining concrete. Background Technology

[0002] To enhance the support performance within tunnels, concrete lining is necessary. However, due to the curved or circular structure of tunnels, the concrete is prone to defects such as voids, gaps, or lack of density. Therefore, it is necessary to pre-embed grouting pipes in these defect-prone areas. After the concrete lining is completed, cement grout with adhesive and filling properties is injected into these defective areas through the pre-embedded grouting pipes to compensate for these defects and increase the service life and support strength of the lining concrete.

[0003] In related technologies, grouting pipes are mostly perforated pipes, meaning the output end is sealed. Cement grout is pumped out through holes in the pipe body. By sealing the pipe opening, high pressure is created inside, allowing the grout to be evenly pumped out through multiple holes to fill the defect. However, during the pre-embedding of grouting pipes, the combined effects of their own weight, concrete covering, and vibration during concrete lining can cause displacement or detachment, thus affecting the grouting of the defect. Summary of the Invention

[0004] This invention provides a method for pre-embedding grouting pipes in tunnel lining concrete, which can reduce the vibration or impact on the grouting pipes, making them more stable during the concrete lining process. The technical solution of this invention is as follows:

[0005] A method for pre-embedding grouting pipes in tunnel lining concrete includes:

[0006] The grouting pipe is passed through the reserved hole of the lining trolley, so that one end of the grouting pipe abuts against the preset position of the tunnel surrounding rock; wherein, the end of the grouting pipe abutting against the tunnel surrounding rock is sealed, and the pipe body is machined with multiple grouting holes.

[0007] A buffer layer is wrapped around the grouting pipe; wherein, the buffer layer comprises an outer layer made of a positive Poisson's ratio material and an inner layer made of a negative Poisson's ratio material, the outer layer and the inner layer are fixed by multiple point connections, the point connections are that the outer layer and the inner layer are fixedly connected by multiple fixing points, and the buffer layer is processed with through holes penetrating the inner layer and the outer layer;

[0008] The grouting pipe is fixed to the steel reinforcement support with tie wire;

[0009] Concrete is poured between the platform of the lining trolley and the surrounding rock of the tunnel, and vibrated using a vibrator. After the concrete has cured and bonded, the grouting pipe is pre-embedded.

[0010] Preferably, the positive Poisson's ratio material is an elastic rubber material, and the negative Poisson's ratio material is a polyurethane foam or polytetrafluoroethylene.

[0011] Preferably, before wrapping the buffer layer outside the grouting pipe, the method further comprises:

[0012] Wrapping a porous wrapping layer outside the grouting pipe; wherein the material for preparing the porous wrapping layer comprises cotton and / or fiber fabric, and further comprises non-woven fabric.

[0013] Preferably, the method of point connection comprises:

[0014] Applying glue on the preset fixed points of the outer layer or the inner layer for connection;

[0015] Or,

[0016] Passing a fixed bolt through the preset fixed points of the outer layer and the inner layer for connection.

[0017] Preferably, the thickness of the inner layer is greater than the thickness of the outer layer.

[0018] Preferably, before wrapping the buffer layer outside the grouting pipe, the method further comprises:

[0019] Laying graphite powder or lubricating oil between the inner layer and the outer layer.

[0020] Preferably, before passing the grouting pipe through the reserved hole of the lining trolley, the method further comprises:

[0021] Pasting a directional fiber felt on the inner wall of the tunnel surrounding rock; wherein the fibers of the directional fiber felt are distributed longitudinally along the inner wall of the tunnel surrounding rock, and the bottom of the directional fiber felt is inserted into a pre-formed drainage groove.

[0022] Preferably, after pasting the directional fiber felt on the inner wall of the tunnel surrounding rock, the method further comprises:

[0023] Installing a baffle on the upper end of the drainage groove to prevent concrete from entering the drainage groove.

[0024] Preferably, the gap between the fibers of the directional fiber felt is 30-60 μm.

[0025] Preferably, after completing the pre-burying of the grouting pipe, the method further comprises:

[0026] A vacuum device connected to the drainage trough creates negative pressure within the drainage trough. The vacuum device includes a housing and a vacuum pipe. One end of the vacuum pipe connects to the interior of the housing, and the other end connects to the drainage trough. A hollow column tangent to the inner wall of the housing is disposed inside the housing. The height of the hollow column matches the height of the inner cavity of the housing. A rotating shaft extending through the housing is disposed along the axis of the hollow column, driving the hollow column to rotate within the housing. A plate is fixedly connected to one end of the hollow column by a spring. The plate extends through a pre-reserved gap in the hollow column and abuts against the inner wall of the housing. An air inlet and an air outlet are respectively disposed on both sides of the housing. The air inlet is connected to the vacuum pipe, and the air outlet is connected to the external environment.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] In this embodiment, after securing the grouting pipe with wire, a buffer layer is wrapped around its exterior. This buffer layer reduces the impact of external vibrations on the internal grouting pipe. Whether it's the high-frequency vibration of the vibrator or the large-amplitude impact of concrete falling onto the grouting pipe, the buffer layer weakens these effects, thus ensuring the stability of the grouting pipe. Specifically, the outer layer is made of a positive Poisson's ratio material, which absorbs and buffers high-frequency vibrations. When a large-amplitude impact hits the grouting pipe, the inner layer, made of a negative Poisson's ratio material, contracts and densifies near the point of impact, spreading the impact evenly and weakening its energy. In summary, this invention reduces the vibration or impact on the grouting pipe, making it more stable during concrete lining and thus enabling better grouting of defective areas. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the buffer layer under no pressure in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the outer layer of the buffer layer under direct pressure in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the structure of the inner layer of the buffer layer under direct pressure in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of an air extraction device provided in an embodiment of the present invention.

[0034] In the diagram: 1-outer layer; 2-inner layer; 3-through hole; 4-shell; 5-exhaust pipe; 6-hollow cylinder; 7-rotating shaft; 8-exhaust hole; 9-inlet hole; 10-spring; 11-plate. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] like Figures 1 to 4 As shown in the figure, this embodiment provides a method for pre-embedding grouting pipes in tunnel lining concrete, including:

[0037] The grouting pipe is passed through the reserved hole of the lining trolley, so that one end of the grouting pipe abuts against the preset position of the tunnel surrounding rock; wherein, the end of the grouting pipe abutting against the tunnel surrounding rock is sealed, and the pipe body is machined with multiple grouting holes.

[0038] A buffer layer is wrapped around the grouting pipe; wherein, the buffer layer consists of an outer layer 1 made of positive Poisson's ratio material and an inner layer 2 made of negative Poisson's ratio material. The outer layer 1 and the inner layer 2 are fixed by multiple point connections. The point connections are fixed by multiple fixed points between the outer layer 1 and the inner layer 2. The buffer layer is processed with through holes 3 that penetrate the inner layer 2 and the outer layer 1.

[0039] The grouting pipe is fixed to the steel reinforcement support with tie wire;

[0040] Concrete is poured between the platform of the lining trolley and the surrounding rock of the tunnel, and vibrated with a vibrator. After the concrete has cured and bonded, the grouting pipe is pre-embedded.

[0041] In this embodiment, after securing the grouting pipe with wire, a buffer layer is wrapped around the outside of the grouting pipe to further increase its stability. The buffer layer reduces the impact of external vibrations on the internal grouting pipe. Whether it is the high-frequency vibration of the vibrator or the large-amplitude impact generated by concrete falling onto the grouting pipe, the buffer layer can weaken it, thereby achieving the stability of the grouting pipe. Specifically, the outer layer 1 is made of a positive Poisson's ratio material, which has a certain elasticity. When high-frequency vibrations are transmitted to the outer layer 1, the material of the outer layer 1 absorbs and buffers the high-frequency vibrations through strain changes. When a large-amplitude impact hits the grouting pipe, the negative Poisson's ratio material of the inner layer 2 shrinks and densifies near the point of impact, spreading the point impact evenly, thereby weakening the impact energy.

[0042] It should be noted that during the concrete pouring stage, after the concrete covers the outer layer 1, it applies a compressive force to the outer layer 1. Under this compressive force, the outer layer 1 thins, and the through holes 3 on the outer layer 1 narrow accordingly. The narrowed or even closed through holes 3 can prevent external concrete from entering the through holes 3. During the grouting stage through the grouting pipe, the cement grout overflowing from the grouting hole compresses the inner layer 2. While being subjected to vertical compression, the cement grout also exerts a certain amount of lateral compression on the hole wall as it passes through the through holes 3. The inner layer 2 is a negative Poisson's ratio material, and the lateral compression further increases the vertical compression, reducing the thickness of the inner layer 2. This releases the compression space of the outer layer 1 during the concrete pouring stage. After the outer layer 1 releases its stress, the size of its through holes 3 returns to normal, allowing the cement grout to smoothly enter the concrete defects through the through holes 3.

[0043] It should also be noted that the inner layer 2 and the outer layer 1 need to be connected by a point connection so that the inner layer 2 and the outer layer 1 can achieve a certain degree of interlayer sliding when they shrink or stretch.

[0044] When preparing the buffer layer, the materials for preparing the outer layer 1 and the materials for preparing the inner layer 2 can be stacked first, and then point connections can be made at evenly distributed fixed points. Finally, through holes 3 can be opened on the stacked inner layer 2 and outer layer 1.

[0045] In this embodiment, Figures 2 to 3The image only shows the deformation of the outer layer 1 and the inner layer 2 under the pressure of concrete and cement slurry. Of course, when the outer layer 1 is compressed, the inner layer 2 will also be compressed, and the through hole 3 will become larger. However, the smaller through hole 3 of the outer layer 1 can block the external concrete. When the inner layer 2 is compressed, the outer layer 1 will also be compressed. After being compressed by the pumped cement slurry, the pumped cement slurry has a large hydraulic pressure and a stronger force, and the inner layer 2 can be compressed and contracted to a greater extent. However, since the inner layer 2 is a negative Poisson's ratio material, the material becomes very dense after shrinkage and has strong support, which greatly reduces the pressure acting on the outer layer 1. In addition, when the cement slurry overflows from the through hole 3 of the outer layer 1, it will also exert a lateral pressure on the outer layer 1 through the inner wall of the through hole 3, causing the through hole 3 to return to its initial state. The through hole 3 can even become larger after the inner layer 2 releases space.

[0046] In some embodiments of the present invention, the positive Poisson's ratio material is an elastic rubber material, and the negative Poisson's ratio material is polyurethane foam or polytetrafluoroethylene. Of course, the negative Poisson's ratio material can also be other suitable materials, such as metamaterials with structures, or negative Poisson's ratio materials with a certain strain capacity.

[0047] In some embodiments of the present invention, before wrapping the grouting pipe with a buffer layer, the method further includes:

[0048] A porous coating layer is wrapped around the outside of the grouting pipe; the porous coating layer is prepared from materials including cotton and / or fiber fabrics, and also includes non-woven fabrics.

[0049] In this embodiment, the buffer layer is wrapped around the porous coating layer. The porous coating layer can quickly absorb the cement grout output from the grouting hole, thereby applying a force perpendicular to the inner layer 2, which facilitates the entire inner layer 2 to be compressed and thinned under stress.

[0050] In some embodiments of the present invention, the point connection method includes:

[0051] Apply glue to the pre-set fixing points on the outer layer 1 or the inner layer 2 to make connections;

[0052] Alternatively, fixing bolts can be inserted through the pre-set fixing points of the outer layer 1 and the inner layer 2 for connection.

[0053] In this embodiment, the fixing bolt can be a countersunk bolt.

[0054] In some embodiments of the present invention, the thickness of the inner layer 2 is set to be greater than the thickness of the outer layer 1. In this embodiment, after the thicker inner layer 2 is compressed and thinned, a larger space can be released so that the outer layer 1 can recover under the action of elastic stress.

[0055] In some embodiments of the present invention, before wrapping the grouting pipe with a buffer layer, the following is also included:

[0056] Graphite powder or lubricating oil is laid between the inner layer 2 and the outer layer 1. The graphite powder or lubricating oil laid between the inner layer 2 and the outer layer 1 makes it easier for the inner layer 2 and the outer layer 1 to slide relative to each other.

[0057] In some embodiments of the present invention, before passing the grouting pipe through the pre-drilled hole of the lining trolley, the method further includes:

[0058] Oriented fiber felt is pasted onto the inner wall of the tunnel surrounding rock; wherein the fibers of the oriented fiber felt are distributed longitudinally along the inner wall of the tunnel surrounding rock, and the bottom of the oriented fiber felt is inserted into a pre-drilled drainage groove.

[0059] Because tunnels are located inside mountains, the surrounding rock is prone to water seepage. This seepage water often carries metal ions, such as calcium ions in carbonate rock seepage. The seepage water comes into contact with the concrete from the tunnel walls and is difficult to drain. Some ions can corrode the concrete, and large temperature differences between day and night can cause severe freezing damage. To prevent seepage water from damaging the concrete, oriented fiber felt is laid on the inner walls of the tunnel's surrounding rock. The gaps between the fibers create capillary action, which rapidly absorbs water. Combined with gravity, the water is guided through the capillary channels formed by the vertically extending fibers and drained through the drainage channels at the bottom of the oriented fiber felt.

[0060] Understandably, a layer of flexible mortar with waterproof properties can be laid on top of the oriented fiber felt to further enhance its waterproof performance.

[0061] In some embodiments of the present invention, after attaching oriented fiber felt to the inner wall of the tunnel surrounding rock, the method further includes:

[0062] Install a baffle at the top of the drainage channel to prevent concrete from entering the drainage channel.

[0063] In some embodiments of the present invention, the gaps between the fibers of the oriented fiber felt are 30-60 μm, a size that is more conducive to capillary water conduction. It should be noted that if the gaps are too small, the water conduction is poor; if the gaps are too large, the porosity of the oriented fiber felt is too high, the strength decreases, and capillary action is either not formed or is weak, which is not conducive to water conduction.

[0064] In some embodiments of the present invention, after the pre-embedding of the grouting pipe is completed, the method further includes:

[0065] A vacuum device connected to the drainage trough is used to create negative pressure inside the drainage trough. The vacuum device includes a housing 4 and a vacuum pipe 5. One end of the vacuum pipe 5 is connected to the inside of the housing 4, and the other end is connected to the drainage trough. A hollow column 6 is provided inside the housing 4, which is tangent to the inner wall of the housing 4. The height of the hollow column 6 matches the height of the inner cavity of the housing 4. A rotating shaft 7 is provided along the axis of the hollow column 6, which passes through the housing 4. The rotating shaft 7 is used to drive the hollow column 6 to rotate inside the housing 4. A plate 11 is fixedly connected to one end of the hollow column 6 by a spring 10. The plate 11 extends out of the hollow column 6 through a pre-reserved gap and abuts against the inner wall of the housing 4. An air inlet 9 and an air outlet 8 are respectively provided on both sides of the housing 4. The air inlet 9 is connected to the vacuum pipe 5, and the air outlet 8 is connected to the external environment.

[0066] In this embodiment, negative pressure in the drainage channel facilitates water conduction and drainage of the oriented fiber felt. Therefore, an air extraction device is connected to the drainage channel to create negative pressure. Specifically, please refer to... Figure 4 The negative pressure device includes a housing 4 and an exhaust pipe 5. A hollow cylinder 6 inside the housing 4 rotates counterclockwise via a rotating shaft 7. A plate 11 within the hollow cylinder 6 remains in contact with the inner wall of the housing 4 under the action of a spring 10. During the rotation of the hollow cylinder 6, the plate 11 pushes air to expel the gas connected to the exhaust port 8 through the exhaust port 8. As the plate 11 rotates, the volume of the portion connected to the air inlet port 9 on the other side of the plate 11 continuously increases, thereby continuously drawing gas from the drainage tank through the air inlet port 9. After the plate 11 rotates past the tangent point (the tangent position between the housing 4 and the hollow cylinder 6) and the air inlet port 9, the large amount of gas drawn in through the air inlet port 9 is separated from the air inlet port 9. At this point, the large amount of gas is only connected to the exhaust port 8. The plate 11 continues to rotate to expel the large amount of gas drawn in from the exhaust port 8. The continuous rotation of the plate 11 continuously draws gas in from the air inlet port 9 and discharges it from the exhaust port 8. It should be noted that during the rotation of the plate, when the plate 11 rotates to the point of tangency between the hollow cylinder 6 and the shell 4, it retracts into the hollow cylinder 6 and pops out after passing the point of tangency. After the plate 11 rotates past the air inlet 9, it separates the air inlet 9 and the exhaust port 8 again and starts to pump and exhaust air again. The rapid and continuous rotation can extract the gas in the drainage tank. In addition, the water inside the drainage tank can also be discharged through the air inlet 9 and the exhaust port 8 along with the gas, preventing the water inside the drainage tank from accumulating continuously.

[0067] It should be noted that the rotating shaft 7 can be connected to a motor or a manual crank. It can periodically pump out air and drain water, or pump out air and drain water according to rainfall and weather conditions.

[0068] Of course, a guide groove can be provided inside the hollow column 6 to allow the plate 11 to extend and retract in a preset direction. Specifically, the plate 11 is inserted into the guide groove and can slide within it. This arrangement ensures that the direction of extension and retraction of the plate 11 during rotation is limited by the guide groove. The spring 10 can also be provided inside the guide sleeve. Similarly, the spring 10 inside the sleeve can extend and retract along the sleeve direction under the constraint of the sleeve. A sealing strip can be provided on the edge of the plate 11 to increase sealing performance. Lubricating oil can be added at sliding sealing points, such as tangential points, to achieve sliding sealing.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of embedding a grouting pipe in a tunnel lining concrete, characterized in that, The application relates to a method for embedding a grouting pipe in a tunnel lining trolley. The grouting pipe is inserted into a reserved hole of the tunnel lining trolley, and one end of the grouting pipe abuts against a preset position of the tunnel surrounding rock; wherein the end of the grouting pipe abutting against the tunnel surrounding rock is blocked, and the pipe body of the grouting pipe is processed with a plurality of grouting holes; A buffer layer is wrapped outside the grouting pipe; wherein the buffer layer comprises an outer layer made of a positive Poisson's ratio material and an inner layer made of a negative Poisson's ratio material in sequence, the outer layer and the inner layer are fixed through a plurality of point connections, the point connections are fixed connections between the outer layer and the inner layer through a plurality of fixed points, and the buffer layer is processed with a through hole penetrating through the inner layer and the outer layer; The grouting pipe is fixed on a steel support through wire tying; Concrete is poured between the surface of the tunnel lining trolley and the tunnel surrounding rock, and is vibrated by a vibrator, and after the concrete is cured and cemented, the embedding of the grouting pipe is completed.

2. A method of embedding a grout pipe in a tunnel lining concrete according to claim 1, characterized in that, The positive Poisson's ratio material is an elastic rubber material, and the negative Poisson's ratio material is polyurethane foam or polytetrafluoroethylene.

3. A method of embedding a grout pipe in a tunnel lining concrete according to claim 1, wherein Before the buffer layer is wrapped outside the grouting pipe, the method further comprises: A porous wrapping layer is wrapped outside the grouting pipe; wherein the wrapping material of the porous wrapping layer comprises cotton and / or fiber fabric, and further comprises non-woven fabric.

4. The method of embedding and grouting a pipe in a tunnel lining concrete according to claim 1, wherein The method of the point connection comprises: Glue is applied on the preset fixed points of the outer layer or the inner layer for connection; Or, Fixed bolts are arranged on the preset fixed points of the outer layer and the inner layer for connection.

5. The method of embedding and grouting a pipe in a tunnel lining concrete according to claim 1, wherein The thickness of the inner layer is greater than that of the outer layer.

6. The method of embedding and grouting a pipe in a tunnel lining concrete according to claim 1, wherein Before the buffer layer is wrapped outside the grouting pipe, the method further comprises: Graphite powder or lubricating oil is laid between the inner layer and the outer layer.

7. The method of embedding and grouting a pipe in a tunnel lining concrete according to claim 1, wherein Before the grouting pipe is inserted into the reserved hole of the tunnel lining trolley, the method further comprises: A directional fiber felt is pasted on the inner wall of the tunnel surrounding rock; wherein the fibers of the directional fiber felt are distributed longitudinally along the inner wall of the tunnel surrounding rock, and the bottom of the directional fiber felt is inserted into a pre-formed drainage groove.

8. A method of embedding a grout pipe in a tunnel lining concrete according to claim 7, wherein After the directional fiber felt is pasted on the inner wall of the tunnel surrounding rock, the method further comprises: A baffle is arranged on the upper end of the drainage groove to prevent concrete from entering the drainage groove.

9. A method of embedding a grout pipe in a tunnel lining concrete according to claim 7 or 8, characterized in that, The gap between the fibers of the directional fiber felt is 30-60 mu m.

10. A method of embedding a grout pipe in a tunnel lining concrete according to claim 7 or 8, characterized in that, After the embedding of the grouting pipe is completed, the method further comprises: A negative pressure is generated in the drainage groove by using an air extraction device connected with the drainage groove; wherein the air extraction device comprises a shell and an air extraction pipe, one end of the air extraction pipe is communicated with the inside of the shell, the other end of the air extraction pipe is communicated with the drainage groove, a hollow cylinder is arranged in the inside of the shell and is tangent to the inner wall of the shell, the height of the hollow cylinder matches the height of the inner cavity of the shell, a rotating shaft is arranged on the axis of the hollow cylinder and penetrates through the shell, the rotating shaft is used for driving the hollow cylinder to rotate in the shell, a plate body is fixedly connected to one end of the inside of the hollow cylinder through a spring, the plate body extends out of the hollow cylinder through a gap reserved in the hollow cylinder and abuts against the inner wall of the shell, air inlet holes and air outlet holes are arranged on the two sides of the shell, the air inlet holes are communicated with the air extraction pipe, and the air outlet holes are communicated with the external environment.

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