Anti-void grouting pipe and grouting method for tunnel secondary lining arch crown with formwork

Abstract

The present invention discloses a grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel with grouting during formwork retention and a grouting method. It includes a pipe body and a plugging airbag. A grouting pipe cavity and an exhaust and overflow pipe cavity are formed in the pipe body. A plurality of slurry outlets communicating with the grouting pipe cavity and a plurality of exhaust holes communicating with the exhaust and overflow pipe cavity are provided on the pipe body. The slurry outlets and the exhaust holes are both arranged along the length direction of the pipe body. The plugging airbag is placed inside the grouting pipe cavity and configured to plug the slurry outlets in the inflated state. That is, each segmented pipe body along the length extension direction of the pipe body has a slurry outlet path and an exhaust and overflow path, enabling synchronous grouting of void spaces at different depths along the pipe body path. At the same time, a plugging airbag is provided in the grouting pipe cavity, which can fully fill and block the entire grouting pipe cavity in the inflated state, preventing the secondary lining concrete from entering the grouting pipe cavity through the slurry outlets and blocking it, affecting the conduction of the slurry outlet path and the exhaust and overflow path.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel void grouting, and particularly to an anti-void grouting pipe and a grouting method for grouting with formwork at the crown of the secondary lining of a tunnel. Background Art

[0002] During the tunnel excavation process, it is necessary to timely carry out support to ensure construction safety, which is called "primary support" in engineering. After the primary support is completed, the tunnel after preliminary reinforcement needs to be further reinforced, which is called "secondary lining" in engineering. During the pouring process of the secondary lining concrete, due to insufficient pumping pressure, deviation in the installation of the end formwork, etc., it is extremely easy to form a void space at the crown of the tunnel, thus affecting the overall quality of the secondary lining construction and causing potential safety hazards.

[0003] Currently, during the construction of the secondary lining of a tunnel, in order to solve the problem of void at the crown, grouting with formwork is generally adopted. A grouting pipe is installed longitudinally along the center line of the crown of the lining steel formwork trolley. Before the concrete begins to set after pouring, grouting is carried out in a timely manner through the embedded grouting pipe to fill the void space at the crown. The traditional grouting technology with formwork at the crown of the lining has two types: radial grouting and longitudinal grouting. Since the grouting pipe is prone to puncture the waterproof board during the radial grouting process, it is rarely used in actual construction. Therefore, at present, longitudinal grouting is mainly adopted.

[0004] In the traditional longitudinal grouting process, two pipes need to be pre-attached longitudinally along the tunnel, one grouting pipe and one exhaust pipe. Among them, the grouting pipe is drilled with plum blossom-shaped slurry overflow holes, and the exhaust pipe is not drilled. Then, stop-grouting valves are installed at the orifices of both pipes, and the grouting pipe is connected. Finally, freshly mixed mortar is used for grouting. According to factors such as the slurry outflow situation of the exhaust pipe and the grouting pressure, the stop-grouting valves of the exhaust pipe and the grouting pipe are closed successively to end the grouting. For example, the patent application with the application number CN202021205776.4 adopts a technical solution to provide a device for preventing the arch crown of the secondary lining of a tunnel from being voided, including an initial support, a waterproof layer is connected to the bottom of the initial support, an air void layer is below the waterproof layer, a secondary lining is connected to the bottom of the air void layer, a grouting pipe is installed inside the air void layer, the bottom end of the grouting pipe extends below the bottom of the secondary lining, a plurality of grouting holes are evenly formed on the outer side of a section of the grouting pipe located inside the air void layer, a connector one is installed at the bottom of the grouting pipe, an exhaust pipe is installed inside the air void layer and on one side of the grouting pipe, and the bottom end of the exhaust pipe extends below the bottom of the secondary lining. It adopts a grouting and exhaust method with the cooperation of two pipes. Using the above method requires pre-attaching two pipes, and the grouting process is cumbersome; at the same time, the exhaust pipe has a straight-through single-hole structure, and its exhaust port can only achieve the exhaust effect on the air void space where it is located. However, for an independent air void space that is not connected to the air void space where it is located in the grouting path, the gas inside it cannot be well discharged, which affects the final grouting effect and it is difficult to ensure that all air void spaces on the grouting path are fully grouted.

[0005] In order to solve a series of disadvantages existing in the above traditional longitudinal grouting technology and ensure effective grouting of the air void space at the arch crown of the tunnel, the present invention provides a grouting pipe and a grouting method for preventing air voids in the arch crown of the secondary lining of the tunnel with formwork. Summary of the Invention

[0006] In order to overcome the problems existing in the existing air void grouting of tunnels, the present invention provides a grouting pipe and a grouting method for preventing air voids in the arch crown of the secondary lining of the tunnel with formwork, which can not only realize single-pipe synchronous grouting and exhaust, but also effectively grout the air void spaces at different depths on the pipe body path, and ensure that all air void spaces on the grouting path are fully filled.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: to provide a grouting pipe for preventing air voids in the arch crown of the secondary lining of the tunnel with formwork, which includes a pipe body and a plugging airbag. A grouting pipe cavity and an exhaust and overflow pipe cavity are formed inside the pipe body. A plurality of slurry outlet ports communicating with the grouting pipe cavity and a plurality of exhaust holes communicating with the exhaust and overflow pipe cavity are formed on the pipe body. The slurry outlet ports and the exhaust holes are both arranged along the length direction of the pipe body; the plugging airbag is placed inside the grouting pipe cavity and is configured to plug the slurry outlet ports in the inflated state.

[0008] Preferably, the grouting pipe cavity is arranged near the lower part of the pipe body, and the slurry outlet is opened at the bottom of the pipe body; the exhaust overflow pipe cavity is arranged near the upper part of the pipe body, and the exhaust hole is opened at the top of the pipe body.

[0009] Preferably, the slurry outlet has at least one arc-shaped notch extending from the bottom of the pipe body to both sides of the pipe body; the exhaust hole has at least one arc-shaped through hole extending from the top of the pipe body to both sides of the pipe body.

[0010] Preferably, the exhaust hole is a cross-shaped through hole, and the center point of the cross-shaped through hole is located at the highest point of the top of the cross section of the pipe body.

[0011] Preferably, the grouting pipe cavity and the exhaust overflow pipe cavity are sealed and separated in the pipe body by a sealing partition board, and the sealing partition board is an arc-shaped sealing board protruding from the grouting pipe cavity to the exhaust overflow pipe cavity side.

[0012] Preferably, the grouting pipe cavity is provided with an airbag outlet on one side of the operating end of the pipe body, and the inflation port of the plugging airbag is detachably nested in the airbag outlet.

[0013] The present invention also provides a method for preventing voids in the second lining arch crown of a tunnel with formwork grouting, which uses the above-mentioned grouting pipe for preventing voids in the second lining arch crown of a tunnel with formwork grouting, and includes the following steps:

[0014] After the primary support of the tunnel is completed and before the secondary lining starts, the grouting pipe for preventing voids in the second lining arch crown of the tunnel with formwork is pre-pasted along the center line of the arch crown of the waterproof board, and the exhaust hole of the grouting pipe for preventing voids in the second lining arch crown of the tunnel with formwork is closely attached to the top of the waterproof board;

[0015] Inflate the plugging airbag so that the inflated plugging airbag fills the entire grouting pipe cavity, and then pour the secondary lining concrete;

[0016] Before the initial setting of the secondary lining concrete, deflate the plugging airbag and extract it from the grouting pipe cavity, tighten the screw plug at the airbag outlet, then grout into the grouting pipe cavity of the grouting pipe for preventing voids in the second lining arch crown of the tunnel with formwork. When slurry flows out from the exhaust overflow port of the grouting pipe for preventing voids in the second lining arch crown of the tunnel with formwork, tighten the screw plug at the exhaust overflow port to carry out pressure maintenance.

[0017] Preferably, the curved surface radian of the exhaust hole is greater than the radian of the arch crown of the waterproof board.

[0018] Preferably, a grouting valve is provided on the grouting port of the grouting pipe for preventing voids in the second lining arch crown of the tunnel with formwork, and the grouting valve is hermetically connected to the grouting port through an S-shaped adapter; a grout stop valve capable of closing the grouting pipe cavity is provided near the grouting port of the grouting pipe for preventing voids in the second lining arch crown of the tunnel with formwork.

[0019] Preferably, after the pressure holding is completed, tighten the grout stop valve to prevent the grout in the grouting pipe cavity from flowing back, and at the same time close the grouting valve to end the grouting.

[0020] The beneficial effects of the present invention are as follows:

[0021] In the present invention, a plurality of slurry outlets communicating with the grouting pipe cavity and a plurality of exhaust holes communicating with the exhaust overflow pipe cavity are provided along the length direction of the body of the formwork grouting anti-decavitation grouting pipe for the second lining arch crown of the tunnel. The slurry outlet and the grouting pipe cavity form a slurry outlet path, and the exhaust hole and the exhaust overflow pipe cavity form an exhaust overflow path. That is, each segmented pipe body along the length extension direction of the formwork grouting anti-decavitation grouting pipe for the second lining arch crown of the tunnel has a slurry outlet path and an exhaust overflow path, enabling synchronous grouting of the decavitation spaces at different depths on the pipe body path and ensuring that all decavitation spaces on the grouting path are completely filled. At the same time, a sealing airbag is arranged in the grouting pipe cavity, and in the inflated state, it can completely fill and seal the entire grouting pipe cavity, preventing the secondary lining concrete from entering the grouting pipe cavity from the slurry outlet and blocking it, affecting the conduction of the slurry outlet path and the exhaust overflow path.

[0022] In the present invention, at least one exhaust hole is provided at the top of the pipe body to ensure that the air in the decavitation space is completely exhausted, and the curved arc of the exhaust hole is greater than the arc of the waterproof board arch crown. Therefore, even if the exhaust hole is arranged closely against the top of the waterproof board, the air can still circulate.

[0023] In the present invention, the grouting port, the grouting pipe cavity, the slurry outlet, the exhaust hole, the exhaust overflow pipe cavity, and the exhaust overflow port are sequentially formed into a grouting exhaust overflow circuit, providing a good flow path for the mortar during the decavitation grouting process, improving the fluidity and grouting efficiency of the mortar during the grouting process, and at the same time avoiding the secondary grouting of the pipeline for pipe sealing.

[0024] The present invention is realized by using the formwork grouting anti-decavitation grouting pipe for the second lining arch crown of the tunnel. By utilizing the grouting exhaust overflow circuit formed by the formwork grouting anti-decavitation grouting pipe for the second lining arch crown of the tunnel itself, the entire grouting exhaust overflow process is coherent and unobstructed. At the same time, since the exhaust holes of the formwork grouting anti-decavitation grouting pipe for the second lining arch crown of the tunnel are arranged closely against the top of the waterproof board at the highest point of the second lining arch crown, it is ensured that the air in the decavitation space can be completely exhausted during the grouting process. At the same time, by utilizing the characteristics that each segmented pipe body of the formwork grouting anti-decavitation grouting pipe for the second lining arch crown of the tunnel has a slurry outlet path and an exhaust overflow path, for non-connected decavitation spaces, an independent grouting exhaust overflow circuit can also be formed through the slurry outlet and the exhaust hole on the pipe section arranged in the decavitation space, enabling the mortar to fill the decavitation space and improving the grouting quality. Description of the Drawings

[0025] Figure 1Schematic diagram of the appearance of the grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel in Embodiment 1 of the present invention.

[0026] Figure 2 Longitudinal sectional three-dimensional schematic diagram of the grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel in Embodiment 1 of the present invention.

[0027] Figure 3 Cross-sectional schematic diagram of the grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel in Embodiment 1 of the present invention.

[0028] Figure 4 Top view of the grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel in Embodiment 2 of the present invention, provided at the center line of the top of the waterproof board in the arch crown.

[0029] Figure 5 Front view of the grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel in Embodiment 2 of the present invention, provided at the center line of the top of the waterproof board in the arch crown.

[0030] Figure 6 Sectional view of the grouting valve in Embodiment 2 of the present invention.

[0031] The markings of each component in the drawings are as follows:

[0032] 1. Pipe body; 11. Grouting pipe cavity; 12. Exhaust and overflow pipe cavity; 13. Sealing partition board; 111. Grout outlet; 121. Exhaust hole; 101. Grouting port; 102. Exhaust and overflow port; 103. Airbag outlet; 104. Grout stop valve; 2. Sealing airbag; 3. Grouting valve; 31. S-shaped adapter; 4. Pressure gauge; 5. Installation and fixing parts; 6. Secondary lining end form; 61. Upper-stage secondary lining concrete; 62. Secondary lining concrete; 7. Void space; 8. Waterproof board; 9. Tunnel primary support. Detailed implementation manners

[0033] The following elaborates on the preferred embodiments of the present invention in conjunction with the drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0034] Embodiment 1

[0035] Embodiment 1 of the present invention provides a grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel, as Figures 1 to 3As shown, the tunnel secondary lining arch molded grouting anti-emptying grouting pipe comprises a pipe body 1 and a blocking air bag 2, a grouting pipe cavity 11 and an exhaust overflow pipe cavity 12 are formed in the pipe body 1, a plurality of slurry outlets 111 connected to the grouting pipe cavity 11 and a plurality of exhaust holes 121 connected to the exhaust overflow pipe cavity 12 are provided on the pipe body 1, the slurry outlets 111 and the exhaust holes 121 are arranged along the length direction of the pipe body 1; the slurry outlets 111 and the grouting pipe cavity 11 form a slurry outlet path, and the exhaust holes 121 and the exhaust overflow pipe cavity 12 form an exhaust overflow path, that is, each segmented pipe body along the length extension direction of the pipe body 1 of the tunnel secondary lining arch molded grouting anti-emptying grouting pipe has a slurry outlet path and an exhaust overflow path, so that it is possible to achieve synchronous grouting of the empty spaces 7 of different depths on the pipe body 1 path, and ensure that all the empty spaces 7 on the grouting path are completely filled. The blocking airbag 2 is built into the grouting cavity 11 and is configured to block the slurry outlet 111 when inflated. The blocking airbag 2 has a changeable shape. When inflated, it can fill and block the entire grouting cavity 11, thereby blocking the slurry outlet 111 to prevent the secondary lining concrete 62 from entering the grouting cavity 11 from the slurry outlet 111 and blocking it, thereby affecting the conduction of the slurry outlet path and the exhaust overflow path.

[0036] The grouting cavity 11 and the exhaust overflow cavity 12 are sealed and separated in the pipe body 1 through a sealing plate 13. The grouting cavity 11 is arranged near the lower part of the pipe body 1, and the exhaust overflow cavity 12 is arranged near the upper part of the pipe body 1. The cross-sectional area of ​​the grouting cavity 11 is larger than the cross-sectional area of ​​the exhaust overflow cavity 12. Figure 2 and Figure 3 As shown, the isolation plate 13 is an arc-shaped sealing plate protruding from the grouting cavity 11 to one side of the exhaust overflow cavity 12. The exhaust overflow cavity 12 after isolation is crescent-shaped, and the grouting cavity 11 is close to a circular cavity, which can achieve better coordination with the sealing airbag 2, so that the sealing airbag 2 can more comprehensively fill and seal the grouting cavity 11 when inflated.

[0037] The slurry outlet 111 is opened at the bottom of the tube body 1, and the slurry in the grouting cavity 11 flows out from the slurry outlet 111. The slurry outlet 111 has at least one arc-shaped slot extending from the bottom of the tube body 1 to both sides of the tube body 1; the exhaust hole 121 is opened at the top of the tube body 1, and the external gas enters the exhaust overflow cavity 12 from the exhaust hole 121 and is discharged. The exhaust hole 121 has at least one arc-shaped through hole extending from the top of the tube body 1 to both sides of the tube body 1. Figure 1 and Figure 3As shown, the slurry outlet 111 is an arc-shaped notch symmetrically extending from the longitudinal center line of the cross-section of the pipe body 1 to both sides of the pipe body 1, so that the slurry in the grouting pipe cavity 11 can flow out quickly at a larger range of angles. The exhaust hole 121 is a cross-shaped through hole. Since the slurry fills the void space 7 from bottom to top, the center point of the cross-shaped through hole is located at the highest point of the top of the cross-section of the pipe body 1 to ensure that the air in the void space 7 is completely exhausted. Further preferably, the curved arc of the exhaust hole 121 is larger than the vault arc of the waterproof board 8. Even if the exhaust hole 121 is arranged closely against the top of the waterproof board 8, the air can still circulate. Moreover, compared with the conventional round hole design, the cross-shaped through hole design can prevent the slurry from prematurely overflowing into the exhaust overflow pipe cavity 12 due to the relatively large opening size. As Figure 1 and Figure 2 shown, the cross-shaped through hole is symmetrically provided with V-shaped grooves on both sides of the pipe body 1 with the longitudinal center line of the cross-section of the pipe body 1. Based on the situation that the diameter of concrete coarse aggregate is generally above 5 mm and the particle size of the micro-expansion grouting material of the mortar raw material is generally below 4.75 mm, the width of the notch of the slurry outlet 111 is preferably 5 mm.

[0038] As Figure 1 and Figure 2 shown, in each segmented pipe body along the length extension direction of the tunnel secondary lining arch crown grouting anti-decavitation grouting pipe body 1, each slurry outlet 111 forms a slurry outlet path with the grouting pipe cavity 11 respectively. Then, the pipe body 1 of the tunnel secondary lining arch crown grouting anti-decavitation grouting pipe is provided with multiple slurry outlet paths along its length extension direction; each exhaust hole 121 forms an exhaust overflow path with the exhaust overflow pipe cavity 12 respectively. Then, the pipe body 1 of the tunnel secondary lining arch crown grouting anti-decavitation grouting pipe is provided with multiple exhaust overflow paths along its length extension direction, that is, each segmented pipe body along the length extension direction of the tunnel secondary lining arch crown grouting anti-decavitation grouting pipe has a slurry outlet path and an exhaust overflow path, so as to realize synchronous grouting of the void spaces 7 at different depths on the path of the pipe body 1 and ensure that all the void spaces 7 on the grouting path are completely filled; and each slurry outlet path and exhaust overflow path are independent, so that even if some slurry outlets 111 and exhaust holes 121 are blocked, it does not affect the conduction of other slurry outlet paths and exhaust overflow paths.

[0039] As Figure 1 and Figure 3 shown, a grouting port 101 and an exhaust overflow port 102 are respectively arranged on one side of the grouting pipe cavity 11 and the exhaust overflow pipe cavity 12 close to the operation end of the pipe body 1. The grouting port 101, the grouting pipe cavity 11, the slurry outlet 111, the exhaust hole 121, the exhaust overflow pipe cavity 12 and the exhaust overflow port 102 form a grouting exhaust overflow loop in sequence, providing a good flow path for the mortar during the void grouting process, improving the fluidity and grouting efficiency of the mortar during the grouting process, and at the same time avoiding the secondary grouting of the pipeline for pipe sealing.

[0040] The bladder of the plugging bladder 2 is arranged along the extending direction of the cavity length of the grouting pipe cavity 11. An inflation port is provided at the operating end of the bladder relative to the pipe body 1. The grouting pipe cavity 11 is provided with a bladder outlet 103 on one side of the operating end of the pipe body 1. The inflation port of the plugging bladder 2 is detachably nested in the bladder outlet 103. When the plugging bladder 2 is in an unfilled state, the plugging bladder 2 is arranged in a strip shape and has a diameter smaller than that of the bladder outlet 103, and can be withdrawn from the bladder outlet 103. Specifically, a spiral sealing nesting method or a sealing ring nesting method can be adopted between the inflation port of the plugging bladder 2 and the bladder outlet 103, as long as detachable sealing is satisfied.

[0041] In addition, to prevent mortar from overflowing from the slurry outlet 111 near the grouting port 101 during the grouting process, causing "false grouting" and extrusion of the secondary lining end form 6, as Figure 1 and Figure 4 shown, the outer wall of the pipe body 1 at one end of the tunnel secondary lining arch crown grouting anti-void grouting pipe near the grouting port 101 is sealed. Preferably, the length of the pipe body 1 with the outer wall sealed is one-fourth of the overall length of the pipe body 1 of the tunnel secondary lining arch crown grouting anti-void grouting pipe.

[0042] For the tunnel secondary lining arch crown grouting anti-void grouting pipe described in Embodiment 1 of the present invention, by arranging a sealing partition 13 inside the pipe body 1 to divide the internal space of the pipe body 1 into an upper exhaust and overflow pipe cavity 12 and a lower grouting pipe cavity 11, the combination of grouting and exhaust on a single pipe is realized, and a slurry outlet 111 communicating with the grouting pipe cavity 11 and an exhaust hole 121 communicating with the exhaust and overflow pipe cavity 12 are arranged on each segmented pipe body to form a slurry outlet path and an exhaust and overflow path. Thus, each segmented pipe body of the tunnel secondary lining arch crown grouting anti-void grouting pipe has a slurry outlet path and an exhaust and overflow path, so as to synchronously grout the void spaces 7 at different depths on the path of the pipe body 1, which not only reduces the space occupied by the grouting pipe body 1, but also simplifies the installation work of the pipe body 1 and improves the grouting efficiency.

[0043] Embodiment 2

[0044] Embodiment 2 of the present invention provides a method for preventing voids in the tunnel secondary lining arch crown grouting, which is realized by using the tunnel secondary lining arch crown grouting anti-void grouting pipe in Embodiment 1, and includes the following steps:

[0045] S1. After the initial support 9 of the tunnel is completed and before the secondary lining starts, the tunnel secondary lining arch crown grouting anti-void grouting pipe is pre-pasted along the center line of the arch crown of the waterproof board 8, and the exhaust holes 121 of the tunnel secondary lining arch crown grouting anti-void grouting pipe are closely arranged against the top of the waterproof board 8.

[0046] As Figure 4 and Figure 5As shown in the figure, by arranging the non-decavitation grouting pipe for the second lining arch crown of the tunnel with formwork grouting at the center line of the top of the waterproof board 8 and setting the exhaust hole 121 of the non-decavitation grouting pipe for the second lining arch crown of the tunnel at the highest point of the second lining arch crown, it is ensured that the air in the decavitation space 7 can be completely exhausted during the grouting process. As Figure 4 shown in the figure, when pre-pasting the non-decavitation grouting pipe for the second lining arch crown of the tunnel, the sealed end of the non-decavitation grouting pipe for the second lining arch crown of the tunnel is abutted against the second lining concrete 61 of the previous stage.

[0047] A grouting valve 3 is provided on the grouting port 101 of the non-decavitation grouting pipe for the second lining arch crown of the tunnel, and a grout stop valve 104 capable of closing the grouting pipe cavity 11 is provided at a position close to the grouting port 101 of the non-decavitation grouting pipe for the second lining arch crown of the tunnel. Since the gap between the non-decavitation grouting pipe for the second lining arch crown of the tunnel and the arch crown is small after it is installed on the second lining arch crown, it is not convenient for subsequent grouting operations. Therefore, as Figure 5 and Figure 6 shown in the figure, the grouting valve 3 is hermetically connected to the grouting port 101 through an S-shaped adapter 31. Preferably, one end of the S-shaped adapter 31 connected to the grouting valve 3 is arranged below the pipe body 1 relative to the exhaust hole 121 of the non-decavitation grouting pipe for the second lining arch crown of the tunnel. The setting of the S-shaped adapter 31 can increase the distance between the grouting valve 3 and the arch crown, thereby increasing the operable space of the grouting valve 3 and facilitating the subsequent grouting operation. Preferably, the grouting valve 3 and the S-shaped adapter 31 can be pre-installed on the non-decavitation grouting pipe for the second lining arch crown of the tunnel and then pre-pasted and installed together with the non-decavitation grouting pipe for the second lining arch crown of the tunnel to the top of the arch crown waterproof board 8. The grout stop valve 104 can close the grouting pipe cavity 11 after the grouting pressure is maintained, enabling the staff to disassemble the slurry conveying pipeline from the grouting machine to the grouting port 101 including the grouting valve 3 in time for cleaning, and at the same time avoiding the problem of the already grouted slurry flowing back from the grouting port 101 after the slurry conveying pipeline is disassembled.

[0048] As Figure 4 and Figure 5 shown in the figure, the non-decavitation grouting pipe for the second lining arch crown of the tunnel is arranged on the top of the waterproof board 8 through the installation fixture 5. During the installation process of the non-decavitation grouting pipe for the second lining arch crown of the tunnel, if ordinary metal fasteners are used for bolt fastening installation, there will be a problem that the bolt drills through the waterproof board 8 and damages its waterproof performance. Therefore, in order to avoid the problem of the installation fixture 5 damaging the waterproof board 8, it is preferred to use the installation fixture 5 made of the same material as the waterproof board 8, and the installation fixture 5 and the waterproof board 8 are connected by hot melt welding to ensure the integrity of the waterproof board 8 to the greatest extent.

[0049] S2. Fill the plugging airbag 2 with gas so that the inflated plugging airbag 2 fills the entire grouting pipe cavity 11, and then pour the secondary lining concrete 62.

[0050] S3. Before the initial setting of the secondary lining concrete 62, deflate the plugging airbag 2 and withdraw it from the grouting pipe cavity 11. Tighten the screw plug at the airbag outlet 103. Then, grout into the grouting pipe cavity 11 of the formwork grouting anti-voiding grouting pipe at the crown of the tunnel secondary lining. When slurry flows out from the exhaust overflow port 102 of the formwork grouting anti-voiding grouting pipe at the crown of the tunnel secondary lining, tighten the screw plug at the exhaust overflow port 102 to maintain pressure.

[0051] Specifically, before the initial setting of the secondary lining concrete 62, first deflate the plugging airbag 2 and withdraw it from the grouting pipe cavity 11, and plug and seal the airbag outlet 103. Then, grout into the grouting pipe cavity 11 of the formwork grouting anti-voiding grouting pipe at the crown of the tunnel secondary lining. The mortar synchronously flows into each void space 7 through the slurry outlet 111 arranged along the length extension direction of the pipe body 1, while the gas in the void space 7 is discharged into the exhaust overflow pipe cavity 12 through the exhaust hole 121 and discharged from the exhaust overflow port 102. After the void space 7 is filled with mortar, the mortar enters the exhaust overflow pipe cavity 12 from the exhaust hole 121 to fill the exhaust overflow pipe cavity 12 until the mortar overflows from the exhaust overflow port 102. Tighten the screw plug at the exhaust overflow port 102 to maintain pressure.

[0052] During the whole grouting process, the mortar sequentially passes through the grouting port 101, the grouting pipe cavity 11, the slurry outlet 111, the exhaust hole 121, the exhaust overflow pipe cavity 12 and the exhaust overflow port 102 to form a grouting exhaust overflow circuit. The whole grouting exhaust overflow process is coherent and unobstructed, providing a good flow path for the mortar during the void grouting process, improving the fluidity and grouting efficiency of the mortar during the grouting process. At the same time, after the void space 7 is filled with mortar, the mortar overflows from the exhaust hole 121 into the exhaust overflow pipe cavity 12 for filling, avoiding secondary grouting of the pipeline for pipe sealing.

[0053] Since each segmented pipe body of the formwork grouting anti-voiding grouting pipe at the crown of the tunnel secondary lining has a slurry outlet path and an exhaust overflow path, even if there are mutually unconnected void spaces 7, the slurry outlet 111 and the exhaust hole 121 on the pipe section arranged in the void space 7 can also form an independent grouting exhaust overflow circuit, so that the mortar fills the void space 7, improving the grouting quality.

[0054] The grouting valve 3 is provided with a pressure gauge 4 on the side facing the grouting port 101. Whether the formwork grouting for preventing voids in the arch crown is completed can be judged according to the pressure parameters detected on the pressure gauge 4; it can also be judged according to whether the pressure holding time is sufficient. The preferred pressure holding time is 10 min; or it is determined by checking whether there is slurry seeping out from the gap at the secondary lining end formwork 6. The specific judgment criteria can be determined according to the actual construction. Preferably, as Figure 6 shown, the pressure gauge 4 is arranged on the grouting valve 3, and its sensing end extends into the interior of the grouting valve 3 and is arranged close to the side where the grouting valve 3 is connected to the grouting port 101.

[0055] For the method for preventing voids in the tunnel secondary lining arch crown with formwork grouting according to Embodiment 2 of the present invention, the grouting exhaust and overflow circuit formed by the self of the grouting and exhaust pipe for preventing voids in the tunnel secondary lining arch crown is utilized to make the whole grouting exhaust and overflow process coherent and unobstructed. Since the exhaust hole 121 of the grouting and exhaust pipe for preventing voids in the tunnel secondary lining arch crown is arranged at the highest point of the secondary lining arch crown close to the top of the waterproof board 8, it is ensured that the air in the void space 7 can be completely emptied during the grouting process; by utilizing the characteristics that each sectional pipe body of the grouting and exhaust pipe for preventing voids in the tunnel secondary lining arch crown has a slurry outlet path and an exhaust and overflow path, for the mutually unconnected void spaces 7, an independent grouting exhaust and overflow circuit can also be formed through the slurry outlet 111 and the exhaust hole 121 on the pipe section arranged in the void space 7, so that the mortar fills the void space 7; meanwhile, after the void space 7 is filled with mortar, it overflows from the exhaust hole 121 into the exhaust and overflow pipe cavity 12 for backfilling, which also avoids the secondary grouting of the pipeline for pipe sealing, facilitates the grouting operation, ensures the grouting effect, and improves the grouting quality.

[0056] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural or equivalent process transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel, with mold Characterized in that, It includes a pipe body and a plugging airbag. A grouting pipe cavity and an exhaust and overflow pipe cavity are formed in the pipe body. A plurality of slurry outlets communicating with the grouting pipe cavity and a plurality of exhaust holes communicating with the exhaust and overflow pipe cavity are provided on the pipe body. The slurry outlets and the exhaust holes are both arranged along the length direction of the pipe body; the plugging airbag is placed in the grouting pipe cavity and configured to plug the slurry outlets in the inflated state; the grouting pipe cavity is arranged near the lower part of the pipe body, and the slurry outlets are opened at the bottom of the pipe body; the exhaust and overflow pipe cavity is arranged near the upper part of the pipe body, and the exhaust holes are opened at the top of the pipe body.

2. The grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel according to claim 1, Characterized in that, The slurry outlet at least has an arc-shaped notch extending from the bottom of the pipe body to both sides of the pipe body; the exhaust hole at least has an arc-shaped through hole extending from the top of the pipe body to both sides of the pipe body.

3. The grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel according to claim 1, Characterized in that, The exhaust hole is a cross-shaped through hole, and the center point of the cross-shaped through hole is located at the highest point of the top of the cross section of the pipe body.

4. The grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel according to claim 1, Characterized in that, The grouting pipe cavity and the exhaust and overflow pipe cavity are sealed and partitioned in the pipe body by a partition plate. The partition plate is an arc-shaped sealing plate protruding from the grouting pipe cavity to the exhaust and overflow pipe cavity side.

5. The grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel according to claim 1, Characterized in that, The grouting pipe cavity is provided with an airbag outlet on one side of the operating end of the pipe body, and the inflation port of the plugging airbag is detachably nested in the airbag outlet.

6. A method for preventing void formation in the arch crown of the secondary lining of a tunnel, with mold Characterized in that, Using the grouting pipe for preventing void formation in the arch crown of the secondary lining of a tunnel according to any one of claims 1 to 5, including the following steps: After the initial support of the tunnel is completed and before the secondary lining starts, the grouting pipe for preventing void formation in the arch crown of the secondary lining of the tunnel is pre-pasted along the center line of the arch crown of the waterproof board, and the exhaust holes of the grouting pipe for preventing void formation in the arch crown of the secondary lining of the tunnel are closely attached to the top of the waterproof board; Inflate the plugging airbag so that the inflated plugging airbag fills the entire grouting pipe cavity, and then pour the secondary lining concrete; Before the initial setting of the secondary lining concrete, deflate the plugging airbag and extract it from the grouting pipe cavity, tighten the spiral plug at the airbag outlet, then grout into the grouting pipe cavity of the grouting pipe for preventing void formation in the arch crown of the secondary lining of the tunnel. When slurry flows out from the exhaust and overflow port of the grouting pipe for preventing void formation in the arch crown of the secondary lining of the tunnel, tighten the spiral plug at the exhaust and overflow port to carry out pressure maintenance.

7. The method for preventing void formation in the arch crown of the secondary lining of a tunnel according to claim 6, Characterized in that, The curved surface radian of the exhaust hole is greater than the radian of the arch crown of the waterproof board.

8. The method for preventing void formation in the arch crown of the secondary lining of a tunnel according to claim 6, Characterized in that, A grouting valve is provided on the grouting port of the non-separation grouting pipe for the second lining arch crown of the tunnel. The grouting valve is hermetically connected to the grouting port through an S-shaped adapter; a grout stop valve capable of closing the grouting pipe cavity is provided at the grouting port of the non-separation grouting pipe for the second lining arch crown of the tunnel.

9. The method for non-separation grouting of the second lining arch crown of the tunnel according to claim 8, characterized in that, after the pressure holding is completed, tighten the grout stop valve to prevent the backflow of the slurry in the grouting pipe cavity, and at the same time close the grouting valve to end the grouting.

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