Shield under-pressure bin opening construction method combining mortar bin filling and in-river grouting reinforcement

Abstract

The invention relates to a shield under-pressure cabin opening construction method combining mortar cabin filling with in-river grouting reinforcement, which is used for carrying out rapid cabin opening operation when a shield tunneling machine encounters bad hydrogeological conditions of a fault zone under a river, and comprises the following steps: S1, closing bottom gates of an excavation cabin and an air cushion cabin; s2, preparing inert mortar; s3, sealing protection; s4, a water stop hoop is constructed; s5, the excavation bin is filled compactly; s6, overwater grouting reinforcement and coring inspection are carried out; s7, opening the bin under pressure, cleaning the inert mortar and overhauling; s8, shield tunneling is recovered; a safe and stable bin opening environment is formed through inert mortar and shield tunneling machine external grouting reinforcement, the problem that conventional bin opening operation cannot be implemented when stones on the excavation face of the water-rich fault zone stratum collapse is solved, the bin opening operation requirement is met, meanwhile, soil near the excavation face of the shield tunneling machine is reinforced, and the construction efficiency is improved. And the risk that the excavation face of the adjacent part is broken and rocks collapse again is reduced, the risk that the shield is trapped is reduced, and the method has high application and popularization value in shield tunnel engineering.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction, and in particular to a shield pressure-opening construction method combining mortar bunker filling with river grouting reinforcement. Background Art

[0002] In recent years, with the rapid development of urban infrastructure, shield tunneling has been widely used to cross oceans and large rivers. Due to the development of fissures in the water-rich fault zones on the seabed / riverbed, the instability of the joint structure surface, the easy dumping or collapse of the rock and soil on the excavation surface, and the hydraulic connection between groundwater and surface water, the hydrogeological conditions are complex. During the shield advancement process, broken rocks on the excavation surface often collapse, causing serious stagnation in the warehouse, cutterhead jamming or tool damage. The shield machine's warehouse opening operation is becoming more and more frequent. The conventional mud membrane pressure opening method has a short pressure maintenance durability time. When the excavation surface collapses, it can no longer guarantee safe warehouse entry operations, which will cause the shield to be shut down for a long time and extend the construction period.

[0003] The existing bunker filling technologies have the following shortcomings: 1. The bunker filling uses cement mortar, cement double-liquid slurry or cement slurry, shield mud and other materials, which not only poses a risk of damage to the main drive seal, but also makes cleaning difficult; 2. Most of them are suitable for excavation surfaces without obvious collapse or voids. They are not suitable for broken strata such as fault zones, which are prone to poor excavation surface stability, large-scale collapse, or require long-term bunker opening for disposal, and cannot achieve a safe pressure maintenance effect; 3. They only meet the current short-term bunker opening needs, and no pre-grouting reinforcement is implemented in the area near the shutdown position. Similar opening problems are very likely to occur again after the shield is pushed again.

[0004] Based on this, there is an urgent need for a method for shield filling and opening operations, which enables the shield machine to quickly clean, safely, and stably open the chamber for a long time when encountering adverse hydrogeological conditions in the fault zone, and can play a certain preventive effect on similar collapses in adjacent complex geological areas. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a shield belt pressure opening construction method combining mortar filling and grouting reinforcement in the river, so as to solve the problem in the prior art that the shield machine cannot open the chamber quickly when encountering adverse hydrogeological conditions in the fault zone.

[0006] To achieve the above object, the present invention provides a shield pressure opening construction method combining mortar filling and river grouting reinforcement, which is used for rapid opening operation of the shield machine when encountering adverse hydrogeological conditions in the fault zone under the river, and comprises the following steps: S1. Close the bottom gates of the excavation chamber and the air cushion chamber; S2, preparing inert mortar; S3, sealing protection; S4. Apply water-stop ring; S5. Excavate and fill the warehouse tightly; S6. Water grouting reinforcement and coring inspection; S7. Open the warehouse under pressure to clean the inert mortar and conduct maintenance; S8. Shield tunneling resumes excavation.

[0007] By adopting this technical solution, a safe and stable opening and disposal environment is formed through inert mortar and external grouting reinforcement of the shield machine, which solves the problem of being unable to carry out conventional opening operations when rocks collapse on the excavation surface of the water-rich fault zone strata, reduces the risk of the shield being trapped, saves construction time, and has a high promotion and application value in shield tunnel projects.

[0008] Furthermore, the step S1 includes cleaning the air cushion bin by circulating mud and water, and after the cleaning is completed, closing the gate connecting the excavation bin and the bottom of the air cushion bin.

[0009] By adopting this technical solution, the subsequent injection of inert mortar can be prevented from entering the air cushion chamber, thereby reducing the subsequent cleaning workload.

[0010] Furthermore, the inert mortar in step S2 is prepared by adding slaked lime to the synchronous mortar used when the shield machine is working.

[0011] By adopting this technical solution, the synchronous mortar in the existing mixing site on the ground can be directly utilized to increase the efficiency of obtaining the inert mortar, thereby increasing the efficiency of the warehouse opening operation. The inert mortar has appropriate strength, which can facilitate subsequent cleaning.

[0012] Furthermore, the step S3 includes injecting grease into the cutter head main drive seal, hinge seal and shield tail sealing system of the shield machine to form sealing protection.

[0013] By adopting this technical solution, subsequent mud leakage can be prevented from damaging the seal of the shield machine.

[0014] Furthermore, the step S4 includes injecting double liquid slurry outwardly through the reserved holes of the shield machine shell and the grouting holes of the rear segments of the shield tail, and the double liquid slurry forms a water-stop ring after solidification.

[0015] By adopting this technical solution, the water-stop ring blocks the water seepage channel behind the shield machine, preventing the shield machine from being trapped by subsequent slurry consolidation.

[0016] Furthermore, the step S5 includes injecting the inert mortar prepared in step S2 into the excavation chamber of the shield machine, and discharging the mud in the excavation chamber from the top while injecting the inert mortar, until the excavation chamber and the hollow area of ​​the excavation face are filled with the inert mortar.

[0017] By adopting this technical solution, the excavation chamber and the top cavity can be filled densely.

[0018] Furthermore, the above-water grouting reinforcement in step S6 includes setting up a drilling and grouting platform on the river surface to perform drilling and grouting reinforcement around the shield machine.

[0019] By adopting this technical solution, the water seepage channels around the shield machine can be isolated and the rock and soil stability around the excavation face can be enhanced.

[0020] Furthermore, the coring inspection in step S6 includes taking coring at one point on each side between the first and second rows of holes in front of the cutter head of the shield machine after the shield machine is reinforced by drilling and grouting around the shield machine, and verifying the effect of the drilling and grouting reinforcement around the shield machine by the coring rate.

[0021] By adopting this technical solution, the coring rate can directly reflect the reinforcement effect, and meeting the coring rate requirements can increase the safety of subsequent warehouse opening operations.

[0022] Furthermore, step S7 includes opening the excavation chamber door of the shield machine under pressure after the shield machine pre-drills reserved holes and the main chamber balance valve determines that the inert mortar is stably solidified, and personnel enter through the manlock to gradually clean the solidified inert mortar in the excavation chamber, and then inspect and replace the shield machine's cutter and cutter disc.

[0023] By adopting this technical solution, the solidified inert mortar is cleaned to expose the internal space of the excavation bin, so as to complete the bin opening and maintenance work.

[0024] Furthermore, step S8 includes opening the bottom gates of the excavation chamber and the air cushion chamber after step S7 is completed, and the personnel carrying tools and debris retreat to the mangate for decompression. After the decompression is completed, synchronous mortar is injected through the mud and water pipeline to raise the liquid level of the excavation chamber and the air cushion chamber, and then the shield machine excavation construction is resumed.

[0025] Compared with the prior art, the present invention has the following beneficial effects: By using inert mortar and external grouting reinforcement of the shield machine, a safe and stable opening and disposal environment is formed, which solves the problem of being unable to carry out conventional opening operations when rocks collapse on the excavation surface of the water-rich fault zone. While meeting the needs of opening operations, the soil near the excavation surface of the shield machine is effectively reinforced, reducing the risk of excavation surface broken rocks collapsing in adjacent areas, reducing the risk of shield being trapped, saving construction time, and having a high value of promotion and application in shield tunnel projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic flow chart of the shield pressure opening construction method of the mortar bunker filling combined with river grouting reinforcement in the present invention; Figure 2 It is a schematic diagram of the effect of the water-stop ring hoop in the shield pressure opening construction method of the mortar bunker filling combined with the river grouting reinforcement in the present invention; Figure 3 It is a schematic diagram of the filling effect in the shield pressure opening construction method of the present invention combining mortar filling with river grouting reinforcement; Figure 4 It is a schematic diagram of river surface drilling and grouting in the shield pressure warehouse opening construction method of the present invention combining mortar warehouse filling with river grouting reinforcement; Figure 5 It is a schematic diagram of the longitudinal section of grouting reinforcement in the shield pressure opening construction method of the present invention combining mortar filling and river grouting reinforcement; Figure 6 It is a schematic plan view of grouting reinforcement in the shield pressure opening construction method of the present invention combining mortar filling with river grouting reinforcement. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0028] The present invention provides a shield pressure opening construction method combining mortar filling and grouting reinforcement in the river, which is used for rapid opening operation of the shield machine when it encounters adverse hydrogeological conditions in the fault zone under the river, such as Figure 1 As shown, the following steps are included: S1. Close the gates at the bottom of the excavation chamber and the air cushion chamber: clean the air cushion chamber of the shield machine by circulating mud and water. After the cleaning is completed, close the gates connecting the excavation chamber and the bottom of the air cushion chamber. The gate opening is reduced to 0% to prevent the subsequent injection of inert mortar from entering the air cushion chamber, thereby reducing the workload of subsequent cleaning; Furthermore, before closing the bottom gates of the excavation chamber and the air cushion chamber, the cutter head of the shield machine should be rotated to a predetermined position, and the predetermined position mainly considers the priority and convenience of subsequent chamber opening operations.

[0029] S2. Preparation of inert mortar: Inert mortar is prepared from yellow sand, fly ash, bentonite, slaked lime and water. The weight ratio of the inert mortar per cubic meter is yellow sand: fly ash: bentonite: slaked lime: water = 1180kg: 300kg: 80kg: 150kg: 250kg. The initial setting time of the inert mortar is 3-4 days, and the compressive strength after 7 days is only 0.8MPa. Furthermore, in order to increase the efficiency of obtaining the inert mortar, slaked lime can be directly added to the synchronous mortar used in the shield machine for preparation.

[0030] S3. Sealing protection: Inject grease into the cutter head main drive seal, hinged seal and shield tail sealing system of the shield machine to form sealing protection.

[0031] S4. Construction of water stop ring: Please refer to the attached Figure 2 , double liquid slurry is injected outward through the reserved holes of the shield machine shell and the grouting holes of the rear segment of the shield tail, and the double liquid slurry forms a water-stop ring after solidification; Furthermore, specifically, first verify the position of the segment behind the shield tail, and use the reserved grouting holes to inject cement double liquid slurry into the second to fourth ring segments after the shield tail is removed, with a volume ratio of cement slurry: water glass = 1:1, a cement slurry water-cement ratio of 1.0, and water glass stock solution: water = 1:2; then use the reserved grouting holes to inject the double liquid slurry with a volume ratio of slurry with mud effect: water glass = 20:1, and slurry with mud effect: water = 1:2, and finally use the reserved grouting ball valves for the middle shield and front shield of the shield machine shell to inject the double liquid slurry with mud effect; Furthermore, a ratio test should be carried out on site before injection of the double liquid slurry, and the initial setting time of the double liquid slurry should be controlled within 25~30s.

[0032] S5, filling and compacting the excavation bin: injecting the inert mortar prepared in step S2 into the excavation bin of the shield machine, and discharging the slurry in the excavation bin from the top while injecting the inert mortar, until the excavation bin and the hollow area of ​​the excavation surface are filled with the inert mortar; Furthermore, the inert mortar is mixed on the ground and transported to the tunnel, and then the inert mortar is injected into the excavation chamber by the synchronous grouting pump on the shield machine, from the bottom breast plate reserved hole, the center rotation reserved hole, and the excavation chamber door reserved hole from the bottom to the waist and then to the top. During the grouting, the pressure of the excavation chamber does not exceed 5.0 bar. The thin mud in the excavation chamber is first discharged from the excavation chamber door reserved hole. After the waist is filled densely, it is adjusted to be discharged from the top advance drilled reserved hole to ensure that the excavation chamber and the top cavity are filled densely. Figure 3 As shown, continuous injection should be performed to prevent pipe blockage caused by long-term stagnation. After injection, bentonite should be used to clean the grouting pipeline; Furthermore, the excavation chamber pressure during injection molding shall not exceed 5.0 bar, which is determined by combining the bearing capacity of the main drive seal and the transition chamber door, and shall be reduced by 1-2 bar on the basis of the lower value. At the same time, this pressure shall be controlled at 1.3-1.5 times the water and soil pressure at the top of the excavation face; Furthermore, after the excavation bin is filled, wait for 2-3 days until the inert mortar solidifies, and then check the water seepage in the excavation bin through the reserved holes in the breast plate and the reserved holes in the excavation bin door. If the mortar is dense and there is no water seepage after a small amount of clean water is discharged, the filling is qualified.

[0033] S6. Water grouting reinforcement and coring inspection: Please refer to the attached Figure 4 , the water grouting reinforcement includes setting up a drilling and grouting platform on the river surface, drilling and grouting reinforcement around the shield machine, isolating the water seepage channel around the shield machine, and enhancing the rock and soil stability around the excavation surface; Furthermore, drilling and grouting reinforcement is to use a flat barge to set up a drilling and grouting platform on the water, and adopt a steel casing plus sleeve valve pipe retreat grouting process; Figure 5As shown in the figure, the grouting reinforcement range is mainly from 2m in front of the shield cutterhead to 2.5m above the shield body, with a total reinforcement length of 4.5m, and a reinforcement depth of 4.0m above the arch to 3m into the hard rock. A 0.5m gap is reserved above the shield body to prevent the shield machine from being trapped by the reinforcement body; the reinforcement width is 2.0m on both sides of the excavation contour line, with a total width of 10.5m; Further, such as Figure 6 As shown in the figure, the grouting points are arranged in a plum blossom shape with a spacing of 1.5m. Four rows of holes are arranged, with a total of 30 holes. Among them, the 19 holes close to the shield machine are partially injected with phosphoric acid double liquid slurry. Figure 5 , Figure 6 The middle hole is shown in light grey, and the rest is injected with cement double liquid slurry. Figure 5 , Figure 6 The middle hole is shown in dark grey; Furthermore, the volume ratio of the phosphoric acid double liquid slurry is phosphoric acid solution: water glass = 1:1, phosphoric acid stock solution: water = 1:18, phosphoric acid Baume degree 5°Be', water glass stock solution: water = 1:1.3, water glass Baume degree 18°Be'; the volume ratio of the cement double liquid slurry is cement slurry: water glass = 1:1, the cement slurry water-cement ratio is 1.0, water glass stock solution: water = 1:1.8, water glass Baume degree 15°Be'; the initial setting time of the phosphoric acid double liquid slurry is controlled to be 20-25s; Furthermore, the standard for stopping grouting at a certain depth of a single hole is that the grouting pump pressure increases by 1.0MPa compared with the initial pressure, or the excavation chamber pressure increases to 5.0bar; the lifting height each time is 1.0m, and the grouting pipeline is cleaned with clean water before lifting to prevent pipe blockage. The grouting volume needs to be increased in weak areas such as the hollow area at the top of the shield; before sealing the hole, the sleeve valve pipe above the top of the reinforcement area is swept into pieces, and then low-concentration cement double-liquid slurry is re-injected, with a weight ratio of cement slurry: water glass = 1:1, cement slurry water-cement ratio of 1.0, water glass stock solution: water = 1:3.6, water glass Baume degree 10°Be', and the grouting volume is determined as 1.2 times the theoretical amount of the maximum borehole volume.

[0034] The core sampling inspection includes taking cores at one point on each side between the first and second rows of holes in front of the cutter head of the shield machine after drilling and grouting reinforcement around the shield machine. The core sampling rate verifies the effect of drilling and grouting reinforcement around the shield machine. Preferably, cores are taken at the inner center of the triangle adjacent to the reinforcement point, that is, the point in the reinforcement body that is farthest from the grouting point. The core rate of the original sandy and strongly weathered rock layer is 70%. If the core rate reaches more than 90% after grouting, it proves that the reinforcement effect is good.

[0035] S7. Open the chamber under pressure to clean the inert mortar and conduct maintenance: After the inert mortar is stabilized by pre-drilling the reserved holes of the shield machine and the main chamber balance valve, the chamber is opened under pressure to open the excavation chamber door of the shield machine. The personnel pressurize the chamber to 2.5 bar through the man-operated gate, open the excavation chamber door, and gradually clean the inert mortar in the excavation chamber, clean the stones that are trapped in the excavation chamber, and inspect and replace the cutter and cutter disc. The cleaning order is the excavation chamber, the connecting bolts on the chest plate, the cutter box and the cutter, the cutter disc spokes, and the cutter disc panel. During the cleaning of the excavation chamber, it should be cleaned layer by layer, and the connecting pipe between the excavation chamber and the air cushion chamber should be cleaned first, so as to restore the air cushion chamber and the excavation chamber connected pressure maintenance system. When cleaning layer by layer, the mud inlet pipelines and reserved holes should be cleared simultaneously. Furthermore, judging the stability of the inert mortar consolidation means conducting water seepage observations in the tunnel for three consecutive days. The shield machine pre-drills the reserved holes and drills a 1m exploration hole through the main chamber balance valve. The water seepage is only a small amount of intermittent dripping, which proves that the filling chamber is dense and the reinforcement effect is good.

[0036] Furthermore, the pressure of pressurized operation is set to be 0.5-1.0 bar lower than the central water and soil pressure, and fine-tuned according to the seepage conditions of the exposed excavation surface. The fine-tuning range of single-bin operation should be lower than 0.1 bar. During the cleaning process, the air compressor of the pressure maintenance system is connected to monitor the loading and unloading changes, and the water seepage increases. When the loading time accounts for more than 20% of the total loading and unloading time, the personnel should withdraw from the excavation bin, re-inject new bentonite slurry, and re-establish the pressurized bin environment.

[0037] S8. Shield tunneling resumes: After the work in the chamber is completed, the bottom gates of the excavation chamber and the air cushion chamber are opened, and the personnel carry tools and debris to exit to the mangate for decompression. After the decompression is completed, the liquid level of the excavation chamber and the air cushion chamber is slowly raised through the mud and water pipeline, and then new bentonite slurry is injected until the viscosity of the mud in the excavation chamber reaches 25s. Prepare to turn the cutter head left and right, and resume construction after getting out of trouble.

[0038] The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, certain details in the embodiments should not constitute a limitation of the present invention, and the scope of protection of the present invention shall be defined by the scope of the attached claims.

Claims

1. A shield pressure opening construction method combining mortar filling and grouting reinforcement in the river, which is used for rapid opening of the shield machine when it encounters adverse hydrogeological conditions in the fault zone under the river, and is characterized by: The steps include: S1. Close the bottom gates of the excavation chamber and the air cushion chamber; S2, preparing inert mortar; S3, sealing protection; S4. Apply water-stop ring; S5. Excavate and fill the warehouse tightly; S6. Water grouting reinforcement and coring inspection; S7. Open the warehouse under pressure to clean the inert mortar and conduct maintenance; S8. Shield tunneling resumes excavation.

2. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 1 is characterized by: The step S1 includes cleaning the air cushion bin by circulating mud and water, and after the cleaning is completed, closing the gate connecting the excavation bin and the bottom of the air cushion bin.

3. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 1 is characterized by: In step S2, the inert mortar is prepared by adding slaked lime to the synchronous mortar used when the shield machine is working.

4. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 1 is characterized in that: The step S3 includes injecting grease into the cutter head main drive seal, hinge seal and shield tail seal system of the shield machine to form sealing protection.

5. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 1 is characterized by: The step S4 includes injecting double liquid slurry outwardly through the reserved holes of the shield machine shell and the grouting holes of the rear segments of the shield tail, and forming a water-stop ring hoop after the double liquid slurry solidifies.

6. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 1 is characterized by: The step S5 includes injecting the inert mortar prepared in step S2 into the excavation chamber of the shield machine, and discharging the slurry in the excavation chamber from the top while injecting the inert mortar, until the excavation chamber and the hollow area of ​​the excavation surface are filled with the inert mortar.

7. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 1 is characterized by: The above-water grouting reinforcement in step S6 includes setting up a drilling and grouting platform on the river surface to perform drilling and grouting reinforcement around the shield machine.

8. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 7 is characterized by: The coring inspection in step S6 includes taking coring at one point on each side between the first and second rows of holes in front of the cutter head of the shield machine after drilling and grouting reinforcement around the shield machine, and verifying the effect of drilling and grouting reinforcement around the shield machine through the coring rate.

9. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 1 is characterized by: The step S7 includes opening the excavation chamber door of the shield machine under pressure after the shield machine pre-drills reserved holes and the main chamber balance valve determines that the inert mortar is stably consolidated, and personnel enter through the manlock to gradually clean the inert mortar consolidated in the excavation chamber, and then inspect and replace the shield machine's cutter and cutterhead.

10. The shield pressure opening construction method of mortar filling combined with river grouting reinforcement according to claim 9 is characterized in that: The step S8 includes opening the bottom gates of the excavation chamber and the air cushion chamber after the step S7 is completed, and the personnel carry tools and sundries and retreat to the man gates for decompression. After the decompression is completed, synchronous mortar is injected through the mud and water pipeline to raise the liquid level of the excavation chamber and the air cushion chamber, and then the shield machine excavation construction is resumed.

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