Anti-disengaging construction method for water conservancy tunnel lining

Abstract

The invention relates to an anti-disengaging construction method for a water conservancy tunnel lining, which comprises the following steps: step S101, pre-burying a monitoring system and a grouting system: when reinforcing steel bars of the tunnel lining are bound, burying the monitoring system and the grouting system at a vault of the tunnel lining; s103, a tunnel lining is poured, and backfill grouting is conducted, specifically, the tunnel lining is poured; and when the monitoring system measures that the vault of the tunnel lining is void, backfill grouting is conducted on the vault through the grouting system. According to the anti-disengaging construction method, the vault disengaging condition is monitored in real time through the monitoring system, the lining arch disengaging condition and disengaging position can be accurately fed back, and the backfill effect can be mastered in real time in the backfill grouting process; when the disengaging problem occurs, the grouting system is used for backfill grouting, the grouting system adopts a circulating grouting mode, operation is easy, all technological processes are convenient to construct, materials are saved, the cost is reduced, the engineering construction risk is reduced, applicability is high, and the method can be used for water delivery tunnel lining concrete pouring disengaging prevention construction of any form.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel construction, relates to the lining structure of a tunnel, and particularly relates to a construction method for preventing air voids in the lining of a water conservancy tunnel. Background Technique

[0002] With the rapid development of the domestic urbanization process, in underground water conveyance projects such as urban rail transit, municipal utility tunnels, and water conservancy projects, a composite lining form is often adopted, that is, a layer of concrete lining is poured again inside the initial support segment or shotcrete; due to limited methods for pouring and vibrating the lining concrete of the tunnel, the concrete cannot be effectively vibrated during the process of being pumped to the formwork surface over a long distance, often resulting in the problem of air voids in the arch crown of the lining concrete. Traditional remedial measures for air voids include the following several kinds:

[0003] 1. Reserve a backfill grouting pipe at the arch crown part. This method requires reserving a vertically penetrating grouting pipe for the structure during the process of tying the steel bars of the tunnel lining, and a large number of grouting pipelines need to be buried, which is likely to form a water seepage channel for the lining structure, affecting the quality of the tunnel structure. The workload of plugging the grouting pipes in the later stage is extremely large; and for a water conveyance tunnel, the lining concrete is in a long-term underwater wet environment, and the buried grouting steel pipes will inevitably be corroded, resulting in the corrosion of the steel bars of the lining structure, seriously affecting the structural quality.

[0004] 2. After the construction of the tunnel lining is completed, according to the water seepage situation of the structure, drill holes and grout for backfill in the arch crown range of the tunnel lining. This method does not require reserving backfill grouting pipelines, but the later backfill grouting is not targeted enough, and it is extremely easy to encounter structural steel bars during the drilling process, which will cause irreversible damage to the original lining structure and reduce the lining structure quality.

[0005] Therefore, we propose a construction method for preventing air voids in the lining of a water conservancy tunnel to solve the above problems. Summary of the Invention

[0006] The purpose of the invention is to overcome the deficiencies of the prior art and provide a construction method for preventing air voids in the lining of a water conservancy tunnel that is convenient to use and has relatively high quality.

[0007] To solve the above problems, the technical solution of the invention is as follows:

[0008] A construction method for preventing air voids in the lining of a water conservancy tunnel includes the following steps:

[0009] Step S101, embed a monitoring system and a grouting system:

[0010] When tying the steel bars of the tunnel lining, embed a monitoring system and a grouting system at the arch crown of the tunnel lining;

[0011] Step S103, pour the tunnel lining and conduct backfill grouting:

[0012] Concreting the inner lining of the tunnel;

[0013] When the monitoring system measures the void under the crown of the tunnel inner lining, grouting is carried out through the grouting system to backfill and grout the crown.

[0014] In a further embodiment, the monitoring system includes a number of pressure sensors and a display. The number of pressure sensors are fixedly installed at intervals axially at the top end of the tunnel inner lining, and the number of pressure sensors are all connected to the display.

[0015] In a further embodiment, the number of pressure sensors are arranged in a number of rows, and the number of pressure sensors in each row are arranged along the entire length of the tunnel inner lining;

[0016] An installation included angle is formed between the two outermost rows of pressure sensors.

[0017] In a further embodiment, the grouting system includes a slurry filtering tank, grouting equipment, a grouting pipe and a circulation pipeline. The slurry filtering tank, grouting equipment and grouting pipe are connected together through the circulation pipeline and form a closed-loop line structure;

[0018] The grouting pipe is located inside the tunnel inner lining.

[0019] In a further embodiment, a pressure gauge and a flowmeter are successively installed on the slurry outlet section of the circulation pipeline, and a pressure gauge, a flowmeter and a grout stop valve are successively installed on the slurry return section of the circulation pipeline.

[0020] In a further embodiment, a number of annular installation grooves are formed at intervals on the grouting pipe, and a number of grouting holes are formed on the circumference of the installation grooves.

[0021] In a further embodiment, a sealing ring is sleeved at the installation groove, and the sealing ring is made of an elastic material;

[0022] During grouting, the sealing ring is stretched and the slurry flows out;

[0023] When not grouting, the sealing ring retracts into the installation groove.

[0024] In a further embodiment, both ends of the grouting pipe are connected to the circulation pipeline through sleeves, and the sleeves are located at the bottom end of the tunnel inner lining.

[0025] In a further embodiment, after step S103 of concreting the tunnel inner lining and backfill grouting, the circulation pipeline is removed, and the sleeves are filled and sealed with mortar.

[0026] In a further embodiment, the installation included angle is 30 degrees.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. The anti-void construction method pre-buries a monitoring system and a grouting system at the crown part of the tunnel lining. During the concrete pouring process of the tunnel lining, the crown void condition is monitored in real time through the monitoring system, which can accurately feedback the void condition and void position of the arch part of the lining. During the backfill grouting process, the backfill effect can also be grasped in real time. When void problems occur, the grouting system is used for backfill grouting. The grouting system adopts a cyclic grouting mode, and harmless grouting of the concrete structure is achieved by adjusting the slurry ratio. The operation is simple, the construction of each process is convenient, the materials are saved, the cost is reduced, and the construction risk of the project is lowered. Moreover, it has strong applicability and can be used for anti-void construction during the concrete pouring process of any form of water conveyance tunnel lining, truly realizing the purpose of automatic monitoring of the crown anti-void during the concrete pouring and backfill grouting processes.

[0029] 2. The grouting pipes of this anti-void construction method are arranged along the entire length of the tunnel lining and only penetrate the tunnel lining at both ends of the tunnel, which can avoid the position of structural steel bars. Later, the damage to the original concrete structure can be minimized through the plugging sleeve. The plugging sleeve uses high-strength epoxy polymer cement mortar, and its high strength and waterproof performance prevent problems such as the internal water pressure of the pipeline causing corrosion or oxidation reaction to the internal structure of the concrete through the reserved grouting pipeline, and can effectively protect the water-facing structure of the water conveyance tunnel.

[0030] 3. The pressure sensors of this anti-void construction method adopt distributed compaction sensors, and the pressure sensors are wrapped with aluminum foil, which can not only waterproof but also appropriately reduce the pressure sensitivity and reduce the influence of other factors such as environmental water vapor on the monitoring results. Moreover, the distributed compaction sensors can be used with a small battery. During the construction process, the entire distributed compaction sensor and the battery can be buried in the tunnel lining without leaving an external voltage interface, which is safe, reliable, and easy to operate. Description of the Drawings

[0031] Figure 1 It is a flowchart of an anti-void construction method for a water conservancy tunnel lining;

[0032] Figure 2 It is a schematic diagram of an anti-void construction method for a water conservancy tunnel lining;

[0033] Figure 3 It is a side view of the pressure sensor of an anti-void construction method for a water conservancy tunnel lining;

[0034] Figure 4 It is one of the schematic diagrams of the grouting pipe of an anti-void construction method for a water conservancy tunnel lining;

[0035] Figure 5 It is another schematic diagram of the grouting pipe of an anti-void construction method for a water conservancy tunnel lining;

[0036] Figure 6Schematic diagram of a casing for a construction method of preventing voids in the lining of a hydraulic tunnel.

[0037] In the figure: 1, primary support lining; 2, tunnel lining; 3, monitoring system; 31, pressure sensor; 32, display; 4, grouting system; 41, pressure gauge; 42, flowmeter; 43, grout stop valve; 44, slurry filter tank; 45, grouting equipment; 46, grouting pipe; 461, sealing ring; 462, installation groove; 463, grouting hole; 47, casing; 48, joint; 49, circulation pipeline; α, installation angle. Specific implementation mode

[0038] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0039] Example 1:

[0040] A construction method for preventing voids in the lining of a hydraulic tunnel, as Figures 1 to 6 shown, includes the following steps:

[0041] S101. Embedded monitoring system 3 and grouting system 4

[0042] When constructing the tunnel lining 2 on the inner side of the primary support lining 1 of the tunnel and binding the steel bars of the tunnel lining 2, the monitoring system 3 and the grouting system 4 are buried at the crown position of the tunnel lining 2. The monitoring system 3 is located at the top end of the tunnel lining 2, and the grouting system 4 is located inside the tunnel lining 2 and the tunnel.

[0043] As Figures 2 to 3As shown in the figure, the monitoring system 3 includes a number of pressure sensors 31 and a display 32. The number of pressure sensors 31 is arranged in three rows. The pressure sensors 31 in each row are arranged along the entire length of the tunnel lining 2. There is an installation angle α between the two rows of pressure sensors 31 on the outermost side. The installation angle α is 30°. The outside of the pressure sensors 31 is wrapped with aluminum foil, which can not only prevent water but also appropriately reduce the pressure sensitivity and reduce the influence of other factors such as environmental water vapor on the monitoring results. A number of pressure sensors 31 are all connected to the display 32. The display 32 can be provided with a number of warning lights or be an intelligent display screen, which is used to display the monitoring situation of a number of pressure sensors 31, that is, the concrete pouring density of the arch part of the tunnel lining 2, and can realize the automatic monitoring of the void of the arch part of the tunnel lining 2. Preferably, the pressure sensor 31 adopts a distributed compaction sensor, and the distance between adjacent pressure sensors 31 is 50 cm.

[0044] As Figures 2 to 6 shown, the grouting system 4 includes two pressure gauges 41, two flow meters 42, a grout stop valve 43, a grout filter tank 44, a grouting device 45, a grouting pipe 46 and a circulation pipeline 49. The circulation pipeline 49 is connected to the grouting pipe 46 to form a closed annular structure, which is suitable for circulating grouting. The grouting pipe 46 is fixedly installed inside the top end of the tunnel lining 2. The circulation pipeline 49 is located inside the tunnel. The grouting device 45 is fixedly installed in the middle of the circulation pipeline 49. The grouting device 45 divides the circulation pipeline 49 into two sections. One section located at the output end of the grouting device 45 is the grout outlet section, and one section located at the input end of the grouting device 45 is the grout return section. Pressure gauges 41 and flow meters 42 are fixedly installed at intervals in both the grout outlet section and the grout return section. The grout stop valve 43 and the grout filter tank 44 are also fixedly installed at intervals in the grout return section, realizing the recycling of the grout and monitoring the grouting situation through the pressure gauges 41 and the flow meters 42. The grouting pipe 46 is arranged along the entire length of the tunnel lining 2. A number of annular installation grooves 462 are made at intervals on the grouting pipe 46. A number of grouting holes 463 are made at circumferential intervals inside the installation grooves 462. A sealing ring 461 is sleeved outside the installation grooves 462. The sealing ring 461 is made of rubber or other elastic materials, so that the sealing ring 461 can wrap the installation grooves 462 to block the grouting holes 463 when grouting is not carried out. When grouting, the sealing ring 461 is washed outwards by the grout for grouting, realizing non-discriminatory backfilling in the later stage. Both ends of the grouting pipe 46 are respectively connected to the circulation pipeline 49 through sleeves 47. The sleeves 47 are located at the bottom end of the tunnel lining 2. The sleeves 47 are of a barrel-shaped structure, and the bottom end of the sleeves 47 is open, which is suitable for connecting to the circulation pipeline 49. The bottom end of the grouting pipe 46 is fixedly installed inside the top end of the joint 48. The lower end of the joint 48 extends into the sleeve 47, which is suitable for connecting the grouting pipe 46 and the sleeve 47. Preferably, the sleeve 47 is a PVC pipe, which is convenient for subsequent roughening treatment of the inner wall; the distance between adjacent two installation grooves 462 is 300 mm.

[0045] S103, pouring tunnel lining 2 and backfilling grouting

[0046] 1. After the steel structure of the tunnel lining 2 is tied, the formwork trolley is installed and concrete is poured as required. During the pouring process, the display 32 is used to monitor the hollowing of the vault of the tunnel lining 2 in real time; once the hollow position of the vault is detected, the vault range is backfilled and grouting is performed through the grouting pipe 46; before starting grouting, the stop valve 43 is closed, and the sealing ring 461 of the grouting pipe 46 is flushed open by pouring high-pressure water. The opening pressure should not exceed 1MPa; ensure that the grouting After the pipe 46 can be used normally, the stop valve 43 is opened to start grouting. The grouting adopts graded grouting. The grouting slurry adopts cement slurry consistent with the concrete mix ratio. The water-binder ratio of the cement slurry adopts six levels: 5, 3, 2, 1, 0.7, and 0.5. During grouting, the slurry changes from dilute to concentrated step by step. The water-binder ratio is 5 when the grouting starts. During the grouting process, the injection rate is calculated through the data of the flow meter 42 of the slurry return section and the slurry discharge section of the circulation pipeline 49. The principle of graded adjustment of the slurry water-binder ratio is as follows:

[0047] (1) When the grouting pressure remains unchanged and the injection rate continues to decrease, the current water-binder ratio is maintained;

[0048] (2) When the injection rate is greater than 30L / min, the water-binder ratio can be adjusted according to the specific situation;

[0049] (3) When the injection rate is zero, the stop valve 43 can be closed, and grouting can be continued for 5 to 10 minutes using the water-binder ratio with the highest concentration. During the grouting process, the grouting pressure is controlled not to exceed 70% of the concrete shear strength. The grouting backfill effect can be judged by the monitoring system 3. If the display 32 shows that there is still void space, other measures need to be taken to backfill the void space in a targeted manner.

[0050] After the grouting is completed and the strength is maintained for 7 days, the casing 47 is cleaned with a concrete coring drill and the inner wall of the casing 47 is roughened. Then, the casing 47 is filled and sealed with high-strength epoxy resin mortar, and the display 32 is removed to complete the backfill grouting.

[0051] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preventing hollowing out of a water conservancy tunnel lining, characterized in that: The following steps are involved: Step S101, pre-buried monitoring system (3) and grouting system (4): When tying the steel bars of the tunnel lining (2), a monitoring system (3) and a grouting system (4) are buried in the arch of the tunnel lining (2); Step S103: pouring tunnel lining (2) and backfilling grouting: Casting the tunnel lining (2); When the monitoring system (3) measures that the vault of the tunnel lining (2) is hollow, the vault is backfilled and grouted through the grouting system (4).

2. The anti-cavitation construction method for the lining of a water conservancy tunnel according to claim 1 is characterized in that: The monitoring system (3) comprises a plurality of pressure sensors (31) and a display (32); the plurality of pressure sensors (31) are fixedly installed at axial intervals on the top end of the tunnel lining (2); and the plurality of pressure sensors (31) are connected to the display (32).

3. The anti-cavitation construction method of the water conservancy tunnel lining according to claim 2 is characterized in that: The plurality of pressure sensors (31) are arranged in a plurality of rows, and the plurality of pressure sensors (31) in each row are arranged along the entire length of the tunnel lining (2); An installation angle (α) is formed between the two outermost rows of pressure sensors (31).

4. The anti-cavitation construction method for the inner lining of a water conservancy tunnel according to claim 3 is characterized in that: The grouting system (4) comprises a slurry filtering pool (44), a grouting device (45), a grouting pipe (46) and a circulation pipeline (49); the slurry filtering pool (44), the grouting device (45) and the grouting pipe (46) are connected together through the circulation pipeline (49) to form a closed circulation circuit structure; The grouting pipe (46) is located inside the tunnel lining (2).

5. The anti-cavitation construction method for the inner lining of a water conservancy tunnel according to claim 4 is characterized in that: The slurry discharge section of the circulation pipeline (49) is installed with a pressure gauge (41) and a flow meter (42) in sequence, and the slurry return section of the circulation pipeline (49) is installed with the pressure gauge (41), the flow meter (42) and a slurry stop valve (43) in sequence.

6. The anti-cavitation construction method for the inner lining of a water conservancy tunnel according to claim 5 is characterized in that: The grouting pipe (46) is provided with a plurality of annular mounting grooves (462) at intervals, and the mounting groove (462) is provided with a plurality of grouting holes (463) on its circumference.

7. The anti-cavitation construction method for the inner lining of a water conservancy tunnel according to claim 6 is characterized in that: A sealing ring (461) is mounted on the installation groove (462), and the sealing ring (461) is made of elastic material; During grouting, the sealing ring (461) is stretched and the slurry flows out; When grouting is not performed, the sealing ring (461) retracts into the installation groove (462).

8. The anti-cavitation construction method for the inner lining of a water conservancy tunnel according to claim 7 is characterized in that: Both ends of the grouting pipe (46) are connected to the circulation pipeline (49) through a sleeve (47), and the sleeve (47) is located at the bottom end of the tunnel lining (2).

9. The anti-cavitation construction method for the inner lining of a water conservancy tunnel according to claim 8, characterized in that: After pouring the tunnel lining (2) and backfilling and grouting in step S103, the circulation pipeline (49) is removed and the casing (47) is filled and sealed with mortar.

10. The anti-cavitation construction method for the inner lining of a water conservancy tunnel according to any one of claims 3 to 9, characterized in that: The installation angle (α) is 30 degrees.

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