Tunnel grout-stopping ring point-increasing grouting construction method

Abstract

The invention discloses a tunnel grout stop ring point-increasing grouting construction method. The method comprises the following steps that pipe pieces are installed; hydraulic filling of pea gravels; slurry enters a bent pipe joint through a grouting hole and enters a guide pipe in a grouting groove after being turned by the bent pipe joint, and grouting operation is conducted on the far end of the pipe piece through extension of the guide pipe; grouting is paused, wherein a bent pipe joint is damaged to achieve internal and external communication; near-end grouting is conducted, specifically, slurry enters a bent pipe joint through a grouting hole, and grouting operation is directly conducted on the near end of the pipe piece from inside to outside through the bent pipe joint; and repeating the steps. The method has the beneficial effects that supplementary grouting is conducted through the pre-buried grouting pipe, and the purpose of grouting range diffusion is achieved through a single grouting hole; the pre-buried guide pipe can directly convey the grout to an area where the grout is difficult to diffuse, the guarantee rate of forming a complete and continuous grout stop ring is greatly increased, and engineering risks and potential quality hazards caused by the incomplete grout stop ring are reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tunnel construction, and particularly relates to a tunnel grout-stopping ring point-increasing grouting construction method, which is used in the construction behind the tunnel segment wall to form a continuous closed grout-stopping ring. BACKGROUND

[0002] In tunnel construction, an annular gap is formed between the outer wall of the segment and the excavated rock wall after segment assembly. In order to stabilize the segment lining structure and make it bear force together with the surrounding rock, gravel is filled into the gap in time, and then cement grouting is performed to form a dense gravel-cement stone body. This is crucial for controlling ground deformation, ensuring segment stability and long-term waterproofing of the tunnel, especially in complex conditions such as long and steep slopes, under important buildings or water-rich strata.

[0003] However, in such tunnel projects, a particularly prominent technical problem is to prevent slurry running during subsequent secondary grouting, i.e. the phenomenon of a large amount of slurry flowing forward along the shield tail gap towards the direction of the shield machine. This not only causes waste of grouting materials and non-dense filling behind the lining, but also causes the grouting pressure to be unable to be effectively established, seriously affecting the grouting reinforcement effect and waterproof reliability. To solve this problem, the current conventional process is to apply a rapid-setting double-liquid slurry (cement-silicate) grout-stopping ring at intervals of a certain number of rings (such as 50 rings for straight sections and 30 rings for downhill sections). The grout-stopping ring aims to form a rapid-setting closed barrier in the tunnel to block the subsequent slurry from running forward. However, this process has inherent defects in practical application, which restrict its reliability - the integrity and continuity of the grout-stopping ring are difficult to guarantee: due to the limited number of grouting holes reserved on each segment, the ring flow and diffusion range of the double-liquid slurry injected from a single grouting hole in the gravel gap is severely restricted; the slurry tends to accumulate near the grouting hole and quickly solidify, often failing to effectively penetrate and connect to the far end area between the two adjacent grouting holes. This easily leads to the formation of a locally weak or interrupted grout-stopping ring in the ring direction, which cannot form a continuous and complete sealing ring.

[0004] This defective grout-stopping ring has particularly serious consequences in long and steep downhill sections, as the slope and gravity will exacerbate the slurry loss forward, not only failing to effectively stop the grouting, leading to material waste and non-dense filling, but also failing to effectively reduce the drainage pressure during tunnel operation. Therefore, under the premise of not increasing the number of segment grouting holes and avoiding the increase of manufacturing cost and assembly complexity, ensuring that the slurry injected from the limited grouting holes can form a continuous, complete and reliable ring sealing body has become a key technical problem that needs to be solved to improve the quality of tunnel construction, especially in complex hydrogeological conditions. SUMMARY

[0005] The purpose of the present application is to solve the problems of weak control ability of double-liquid slurry flow direction and uneven slurry diffusion in the existing grouting process, and provide a tunnel grouting ring increasing point grouting construction method, which preforms remote supplementary grouting on the distal end area of the grouting hole through the method of pre-buried pipe, and then directly performs conventional grouting ring construction from the grouting hole after the distal end is supplemented, so as to ensure the integrity and sealing reliability of the grouting ring, effectively avoid the slurry loss problem in the process of backfill grouting, and improve the grouting effect and engineering quality.

[0006] The purpose of the present application is achieved by the following technical solutions: A tunnel grouting ring increasing point grouting construction method, comprising the following steps: Step S1, segment installation: install the grouting segment in the tunnel; Step S2, pea gravel filling; Step S3, distal end grouting: the grouting segment is reserved with a grouting hole and a grouting groove, grouting is performed from inside to outside through the grouting hole, the slurry enters the elbow pipe joint through the grouting hole, and then enters the pipe in the grouting groove through the elbow pipe joint, and the pipe is extended to perform grouting operation on the distal end of the segment; Step S4, pause grouting: destroy the elbow pipe joint to realize internal and external communication; Step S5, proximal end grouting: grouting is performed from inside to outside through the grouting hole, the slurry enters the elbow pipe joint through the grouting hole, and then directly performs grouting operation on the proximal end of the segment from inside to outside through the elbow pipe joint; Step S6, repeat steps S3 to S5 until the grouting ring construction of all the preset grouting holes of the single ring is completed.

[0007] Further, in step S1, the elbow pipe joint and the pipe are installed in the grouting segment during pre-preparation of the grouting segment.

[0008] Further, in step S1, a closed hole cover is arranged at the inner hole of the grouting hole, and a temporary sleeve is arranged at the pipe opening of the pipe; in step S3, the closed hole cover and the temporary sleeve are removed before grouting.

[0009] Further, in step S1, a protective cover plate is arranged on the outer side of the grouting segment, covering the grouting hole and the grouting groove.

[0010] Further, in step S1, it further comprises a surrounding segment, and the grouting segment and the surrounding segment are arranged in sequence and at intervals, and the grouting segment and the surrounding segment jointly form a segment support structure.

[0011] Further, in step S3, whether the pipeline is blocked by sundries is detected before grouting.

[0012] Further, in the steps S3 and S5, the slurry is applied by using cement slurry and water glass double slurry, and the mixing ratio of the double slurry is: water: cement: water glass = 1: 1: 2.

[0013] Further, in the steps S3 and S5, the single-time grouting amount control mode of the grouting operation adopts the double-way control of the grouting pressure and the leakage of the slurry in the observation hole, and the end time of the supplementary grouting is controlled by monitoring the grouting pressure and the leakage of the slurry in the observation hole.

[0014] Further, in the step S6, the grouting pipe segments are grouted one by one from bottom to top.

[0015] Further, in the step S6, the proximal end of the grouting pipe segment is in the counterclockwise direction to the distal end.

[0016] The beneficial effects of the present application are: the grouting range is diffused from a single grouting hole by the supplementary grouting through the pre-embedded grouting pipe; the pre-embedded pipe can directly deliver the slurry to the area where the slurry is difficult to diffuse, greatly increasing the guarantee rate of forming a complete and continuous grouting ring, and reducing the engineering risks and quality risks caused by the incomplete grouting ring; at the same time, the construction process of the pre-embedded pipe does not need to change the existing shield machine and pipe segment assembly process, and mainly optimizes the pipe segment design and manufacturing stage.

[0017] The foregoing main scheme of the present application and each further selected scheme thereof can be freely combined to form multiple schemes, all of which are the schemes that can be adopted and claimed by the present application; and the present application can also be freely combined between the (each non-conflicting selection) selections and between the other selections. Those skilled in the art can understand that there are many combinations according to the existing technology and common knowledge after understanding the schemes of the present application, and all of them are the technical schemes claimed by the present application, which will not be listed here. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 is a schematic diagram of the grouting pipe segment structure of the present application.

[0019] Fig. 2 is a schematic diagram of the local structure of the outer side of the grouting pipe segment of the present application.

[0020] Fig. 3 is a schematic diagram of the construction of the present application.

[0021] In the figure: 100-grouting pipe segment, 200-enclosure pipe segment; 101-grouting hole, 102-closed hole cover, 103-bent pipe joint, 104-grouting groove, 105-pipe, 106-protection cover plate, 107-bolt, 108-temporary sleeve; ①-⑩-first to tenth grouting points. DETAILED DESCRIPTION

[0022] The following non-limiting examples are used to illustrate the present application.

[0023] Embodiment 1 Reference Figs. 1-3 As shown in the figure, a tunnel grouting ring point grouting construction method adopts a grouting pipe piece 100.

[0024] The grouting pipe piece 100 is a prefabricated reinforced concrete structure, which has the function of normal enclosure support, and the grouting pipe piece 100 is also optimized in structure to uniformly grout the back wall. One end of the grouting pipe piece 100 is provided with an internal and external through grouting hole 101, which realizes internal and external communication to grout from the inside to the outside of the pipe piece.

[0025] The outer side of the grouting pipe piece 100 is provided with a grouting groove 104 for the arrangement of a guide pipe 105. The grouting hole 101 and the grouting groove 104 are in communication to facilitate the processing and forming of the structure. The grouting hole 101 and the grouting groove 104 are both pre-buried and arranged during the pipe piece prefabrication process.

[0026] The grouting hole 101 and the grouting groove 104 are in communication with a bend pipe joint 103, which is used to connect the transition and realize the turning of the grout. The bend pipe joint 103 is in communication with the guide pipe 105 in the grouting groove 104, and the two ends of the guide pipe 105 are located at the two ends of the grouting pipe piece 100. Then the grouting operation can be carried out to the distal end through the guide pipe 105, and after completion, the bend pipe joint 103 is damaged, the proximal grouting operation can be carried out, and the grouting range can cover the near and far, so as to ensure the uniformity of grouting. The bend pipe joint 103 and the guide pipe 105 are installed and fixed during the pipe piece prefabrication process.

[0027] The grouting hole 101 is arranged along the radial direction to ensure the rapid communication between the inside and the outside. The inner hole of the grouting hole 101 is provided with a closed hole cover 102, which closes the grouting hole 101 to ensure the smoothness of the grouting hole 101 before grouting, and avoids the blockage caused by the falling of sundries into the hole.

[0028] The bend pipe joint 103 is L-shaped structure, one end of which extends into the grouting hole 101 to realize communication, so that the grout can enter the pipe joint from the grouting hole 101, and the other end of the bend pipe joint 103 is processed with threads to realize the connection and communication with the guide pipe 105, so that the grout is extended through the guide pipe 105 after turning through the bend pipe joint 103.

[0029] The grouting groove 104 is an arc-shaped groove with a size of 1500*20*20 mm, which is preset along the cross-sectional direction of the segment at the grouting hole of the outer wall of the segment during the production of the segment. The guide pipe 105 is a disposable grouting pipe with an inner diameter of 8 mm and an outer diameter of 12 mm, which is fixed between the segment and the segment by epoxy resin structural adhesive, and is placed in the arc-shaped groove to extend to the target area along the outer wall of the segment, i.e. the gap between the outer sides of the adjacent two grouting holes corresponding to the middle point of the segment.

[0030] The guide pipe 105 includes a support steel wire in the inner layer and a composite layer in the outer layer, and the composite layer includes a non-woven filter cloth and a nylon cloth net, i.e. the guide pipe 105 takes a steel spring as a support framework, which can ensure that the grouting channel is continuously smooth, the outer layer is a double filtration layer of composite non-woven filter cloth and nylon wire mesh, which has flexibility and can also ensure the wrapping and conveying of the grout, and the guide pipe can be arranged in the groove of the outer wall of the segment.

[0031] The outer side of the grouting segment 100 is provided with a flexible protective cover plate 106, which covers the grouting hole 101 and the grouting groove 104, and the cover plate width completely covers the guide pipe and the grouting hole to protect and shield the hole and the groove, so as to avoid the damage of sundries to the pipeline. The protective cover plate 106 is a plastic grid, preferably made of glass fiber reinforced plastic, and is fixed on the grouting segment 100 by bolts, and the bolts are used to anchor the cover plate on the segment concrete on both sides of the cover plate. The protective cover plate 106 is made of expanded metal bolts on both sides, and the number of single columns is four, which can anchor the flexible cover plate to the outer wall of the segment.

[0032] A temporary sleeve 108 is arranged at the pipe opening of the guide pipe 105, which is preferably made of rubber and used for sealing and protecting the port. The rubber sleeve is wrapped around the embedded guide pipe port for temporary sealing to prevent damage caused by the process of blowing and filling gravel.

[0033] The construction method includes the following steps: step S1, segment installation: installing the grouting segment 100 in the tunnel and performing normal enclosure support.

[0034] A closed hole cover 102 is arranged at the inner port of the grouting hole 101, and a temporary sleeve 108 is arranged at the pipe opening of the guide pipe 105 to prevent sundries from entering the grouting channel and causing blockage. A protective cover plate 106 is arranged on the outer side of the grouting segment 100, which covers the grouting hole 101 and the grouting groove 104 to prevent the blowing and filling gravel from entering the hole or groove and causing damage. After the installation of the protective measures is completed, the overall firmness is checked.

[0035] The segment also comprises a surrounding segment 200, the grouting segment 100 and the surrounding segment 200 are arranged in sequence and at intervals, and the grouting segment 100 and the surrounding segment 200 jointly form a segment support structure. The grouting segment 100 can perform grouting operation on both ends (proximal end and distal end) of itself, and then adjacent segments do not need to be structurally modified and can use conventional segments. The interval arrangement of the grouting segment 100 also ensures the uniformity of grouting.

[0036] Step S2, pea gravel filling: pea gravel is filled between the outer wall of the segment and the excavated rock wall.

[0037] Step S3, distal end grouting: the grouting segment 100 is provided with a grouting hole 101 and a grouting groove 104, grouting is performed from inside to outside through the grouting hole 101, the grout enters the elbow pipe joint 103 through the grouting hole 101, and after turning through the elbow pipe joint 103, the grout enters the guide pipe 105 in the grouting groove 104, and the grout extends through the guide pipe 105 to perform grouting operation on the distal end of the segment.

[0038] The closure hole cover 102 and the temporary sleeve 108 are removed before grouting. Whether the pipeline is blocked by sundries is detected before grouting. The grout is made of cement grout and water glass double-liquid grout, and the mixing ratio of the double-liquid grout is: water:cement:water glass=1:1:2. The single grouting amount control mode of the grouting operation adopts a double-direction control of grouting pressure and observation hole grout leakage, and the end time of the supplementary grouting is controlled by monitoring the grouting pressure and the observation hole grout leakage.

[0039] The extension of the guide pipe 105 allows the grout to spread and solidify in the distal end target area. This step aims to ensure that the most difficult to fill distal end area is effectively filled first. When the grouting pressure reaches 0.2-0.3 MPa or turbid cement double-liquid grout is observed to flow out, the supplementary grouting stage ends after 5 minutes of continuous pouring, and the grouting is paused.

[0040] Step S4, pause grouting: physically damage the elbow pipe joint 103 to achieve internal and external communication, and create a new channel from the grouting hole to the nearby shield tail gap.

[0041] Step S5, proximal end grouting: grouting is performed from inside to outside through the grouting hole 101, and the grout enters the elbow pipe joint 103 through the grouting hole 101, and then directly grouts the proximal end of the segment from inside to outside through the elbow pipe joint 103. The grout is made of cement grout and water glass double-liquid grout, and the mixing ratio of the double-liquid grout is: water:cement:water glass=1:1:2. The single grouting amount control mode of the grouting operation adopts a double-direction control of grouting pressure and observation hole grout leakage, and the end time of the supplementary grouting is controlled by monitoring the grouting pressure and the observation hole grout leakage.

[0042] When the bend pipe joint 103 is broken, the slurry no longer flows through the embedded conduit, but gushes out from the broken fracture, directly filling the shield tail gap in the proximal region near the grouting hole. When the grouting pressure is detected to reach 0.2-0.3 MPa, or turbid cement double-liquid slurry is observed to flow out, the proximal grouting stage is completed after 5 minutes of continuous grouting, and grouting is stopped.

[0043] Step S6, steps S3 to S5 are repeated until the single-ring all-pre-set grouting hole stop grouting ring construction work is completed. The grouting pipe segment 100 is grouted from bottom to top one by one, the proximal end of the grouting pipe segment 100 is in the counterclockwise direction from proximal to distal, that is, the direction of the upper conduit of the grouting pipe segment is the same, the direction of the conduit is the same in the cross section after the pipe segment is assembled, such arrangement can make the grouting points evenly distributed, and the grouting effect is better. The specific grouting sequence is Fig. 3 The first grouting point ① to the tenth grouting point ⑩ in the middle.

[0044] The foregoing basic examples and each further selected example of the present application can be freely combined to form multiple embodiments, all of which are embodiments that can be used and claimed by the present application. In the present application scheme, each selected example can be arbitrarily combined with any basic example and selected example.

[0045] The above is only the preferred embodiment of the present application, and does not limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A tunnel grout-stopping ring point grouting construction method, characterized in that, It comprises the following steps: Step S1, segment installation: install the segment (100) in the tunnel; Step S2, pea gravel filling; Step S3, distal grouting: the segment (100) is provided with a grouting hole (101) and a grouting groove (104), grouting is performed from inside to outside through the grouting hole (101), the slurry enters the elbow pipe joint (103) through the grouting hole (101), and after being turned by the elbow pipe joint (103), the slurry enters the guide pipe (105) in the grouting groove (104), and the guide pipe (105) is extended to perform grouting on the distal end of the segment; Step S4, pause grouting: destroy the elbow pipe joint (103) to realize internal and external communication; Step S5, proximal grouting: grouting is performed from inside to outside through the grouting hole (101), the slurry enters the elbow pipe joint (103) through the grouting hole (101), and the slurry is directly grouted from inside to outside on the proximal end of the segment through the elbow pipe joint (103); Step S6, repeat steps S3 to S5 until the grouting ring of all the preset grouting holes in a single ring is completed.

2. The construction method of point grouting with tunnel grout-stopping ring according to claim 1, characterized in that: In step S1, the elbow pipe joint (103) and the guide pipe (105) are installed in the segment (100) during prefabrication of the segment (100).

3. The construction method of point grouting with tunnel arch ring according to claim 1, characterized in that: In step S1, a closed hole cover (102) is arranged at the inner side of the grouting hole (101), and a temporary sleeve (108) is arranged at the pipe opening of the guide pipe (105); in step S3, the closed hole cover (102) and the temporary sleeve (108) are removed before grouting.

4. The construction method of point grouting with tunnel arch ring according to claim 1 or 3, characterized in that: In step S1, a protective cover plate (106) is arranged on the outer side of the segment (100), covering the grouting hole (101) and the grouting groove (104).

5. The construction method of point grouting with tunnel arch ring according to claim 1, characterized in that: In step S1, it further comprises a surrounding segment (200), the segment (100) and the surrounding segment (200) are arranged in sequence and at intervals, and the segment (100) and the surrounding segment (200) jointly form a segment support structure.

6. The construction method of point grouting with tunnel spigot ring according to claim 1, characterized in that: In step S3, the pipeline is detected before grouting to check whether it is blocked by impurities.

7. The construction method of point grouting with tunnel spigot ring according to claim 1, characterized in that: In steps S3 and S5, the slurry is made of cement slurry and water glass double-liquid slurry, and the mixing ratio of the double-liquid slurry is: water: cement: water glass = 1:1:

2.

8. The construction method of point grouting with tunnel arch ring according to claim 1 or 7, characterized in that: In steps S3 and S5, the single grouting amount control mode of the grouting operation adopts a double-direction control of grouting pressure and observation hole slurry leakage, and the monitoring of the grouting pressure and the observation hole slurry leakage controls the end time of the supplementary grouting.

9. The construction method of point grouting with tunnel spigot ring according to claim 1, characterized in that: In step S6, the segment (100) is grouted from bottom to top one by one.

10. The construction method of point grouting with tunnel arch ring according to claim 1 or 9, characterized in that: In step S6, the proximal end of the segment (100) is counterclockwise to the distal end.

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