Construction method for plugging deep buried water-rich sewage pipe in deep foundation pit of subway station

Abstract

The present invention discloses a method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station, which is characterized by comprising the following steps: 1) plugging an upstream sewage pipe; 2) pumping out accumulated water in the sewage pipe; 3) plugging a downstream sewage pipe; 4) plugging the sewage pipe mouth. The present invention plugs the upstream water pipe, and uses an airbag lowering hole combined with a concrete pouring hole, and uses the airbag and concrete pouring to plug the upstream sewage pipe, which can create conditions for subsequent plugging construction downstream; at the same time, the present invention injects concrete downstream of the sewage pipe through a grouting pipe to plug the downstream position of the sewage pipe, thereby improving the plugging effect of the sewage pipe and effectively preventing sewage from infiltrating into the subway foundation pit; the method of the present invention has low cost, short construction period, good plugging effect, sewage will not infiltrate into the foundation pit, and solves the problem of excessive site area occupied by plugging construction.

Description

Technical Field

[0001] The invention relates to a sewage pipe plugging construction method, and in particular to a sewage pipe plugging construction method deeply buried in a deep foundation pit of a subway station. Background Art

[0002] In recent years, with the development of urban rail transit, subway projects are basically constructed in prosperous areas of the city. The traffic flow in prosperous areas is large, the pipelines are complex, and the size of pipelines is getting larger and larger, making relocation more and more difficult. In addition, subways are basically located at the intersections of urban main roads. There are a large number of pipelines at the intersections, and there are no conditions for pipeline relocation in other surrounding locations, or the relocation costs are too high. Some subway foundation pits have deep buried sewage pipes.

[0003] At present, the following technical solutions are usually adopted to seal sewage pipes: (1) using slope excavation and pouring concrete to seal; (2) using three-tube jet grouting piles and sleeve valve pipe grouting to reinforce the sealing.

[0004] The above-mentioned traditional construction methods all have the following defects: (1) Slope excavation will occupy the site, be costly, and increase the source of danger; (2) The slurry reinforced by sleeve valve pipe grouting is easily washed away by sewage, resulting in waste and may not achieve the blocking effect. Summary of the invention

[0005] In view of the above problems, the present invention provides a construction method for sealing water-rich sewage pipes deeply buried in deep foundation pits of subway stations. The method of the present invention has low cost, short construction period, good sealing effect, sewage will not seep into the foundation pit, and solves the problem of excessive site area occupied by the sealing construction.

[0006] The present invention is achieved through the following technical solutions.

[0007] The method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station is characterized by comprising the following steps:

[0008] 1) Blocking of upstream sewage pipe

[0009] According to the position of the sewage pipe in the deep foundation pit, the upstream pipeline position is located on the construction access road, and then two air bag lowering holes are drilled at the upstream pipeline position, and the air bag is lowered into the sewage pipe through the air bag lowering holes, and then the air bag is filled with air, and then a concrete pouring hole is drilled at the upstream pipeline position between the two air bag lowering holes, and concrete is poured into the sewage pipe through the concrete pouring hole, so that the concrete fills the pipeline between the two air bags, and after filling, the air bag lowering hole and the concrete pouring hole are blocked;

[0010] 2) Pumping out water from sewage pipes

[0011] Pump out the accumulated water in the downstream sewage pipe. When the accumulated water depth is pumped out to 10-15 cm, place sandbags 2-3 m upstream of the retaining piles in the sewage pipe to block the sewage pipe. Then drain the accumulated water in the sewage pipe downstream of the sandbags.

[0012] 3) Blockage of downstream sewage pipe

[0013] Sandbags are stacked on the outermost side of the sewage pipe outlet as the outer fetal membrane, and a grouting pipe is reserved so that the outer side of the grouting pipe is pressed by the sandbags and fixed with the steel bars in the retaining piles by welding with U-shaped steel bars. Then, the sewage pipe is fully poured with micro-expansive concrete through the grouting pipe. When the concrete strength reaches 80%, the outer sandbags are removed. Then, double-liquid slurry is injected into the pipe through the grouting pipe to stop water. After the grouting is completed, the exposed grouting pipe is cut off;

[0014] 4) Seal the sewage pipe opening

[0015] Clean out the soil and rocks between the retaining piles on both sides of the sewage pipe, control the distance between the soil and rock surface downstream between the retaining piles and the outer wall of the retaining piles to 300mm~400mm, then chisel out the sewage pipe and the concrete inside the pipe at the pipe mouth to reserve space for pouring cast-in-place concrete, then lay cast-in-place steel mesh, install formwork and pour cast-in-place concrete in sequence. After the cast-in-place concrete reaches the set strength, the formwork can be removed for maintenance.

[0016] Preferably, in step (1), the diameters of the airbag lowering holes and the concrete pouring holes are 500 to 750 mm, and the distance between the two airbag lowering holes is 1.5 to 2.5 m.

[0017] Preferably, in step (2), before draining the accumulated water in the sewage pipe, first check whether there are harmful gases in the sewage pipe. If there are no harmful gases, subsequent construction can be carried out; if there are harmful gases, the harmful gases should be removed before subsequent construction.

[0018] Preferably, in step (3), the grouting pipe is a flower pipe, a valve is installed on the outside of the grouting pipe, and the slurry holes are arranged in a plum blossom shape at intervals of 120 to 180 mm along the wall of the grouting pipe. The positions of the slurry holes are 90 degrees to each other, and the diameter of the slurry holes is 5 to 8 mm.

[0019] Preferably, in step (3), the construction mix ratio of the double liquid slurry is, by mass, cement: water glass: water reducing agent = 378:215:14.

[0020] Preferably, in step (3), the micro-expansive concrete is C30 micro-expansive concrete, and when pouring the micro-expansive concrete, the amount of micro-expansive concrete is increased every 0.15 to 0.25 m 3 The concrete is vibrated using an inserted vibrator.

[0021] Preferably, in step (4), after the soil and rocks between the retaining piles on both sides of the sewage pipe are removed, the soil and rocks attached to the pile body should also be cleaned, and the pile body concrete should be roughened, and the roughening should remove at least 75% of the coarse aggregate on the exposed surface.

[0022] Preferably, in step (4), the casting steel mesh is laid by first implanting steel bars on the retaining piles, with the implantation depth being 150 to 250 mm, and then the casting steel mesh is laid, and the main bars of the casting steel mesh are welded to the steel bars implanted on the retaining piles.

[0023] Preferably, in step (4), the cast concrete is C20 concrete, and the cast concrete is gently vibrated or tapped on the outside of the formwork every 0.5 to 1.2 m of pouring height.

[0024] Preferably, in step (4), after the cast concrete is demolded and cured, C20 mesh sprayed concrete and structural exterior walls are constructed on the outside of the cast concrete.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1) The construction method of the present invention can directly block the sewage pipe on the construction access road without the need for slope excavation and concrete pouring. Compared with slope excavation and blocking, it is more economical and has a shorter construction period, and solves the problem of excessive site occupation in conventional sewage pipe blocking construction.

[0027] 2) The construction method of the present invention first blocks the upstream water pipe, and adopts a combination of airbag lowering holes and concrete pouring holes, and uses airbags and concrete pouring to block the upstream sewage pipe, which can create conditions for subsequent downstream blocking construction; then, the present invention injects concrete downstream of the sewage pipe through a grouting pipe to block the downstream position of the sewage pipe, thereby improving the blocking effect of the sewage pipe and effectively preventing sewage from seeping into the subway foundation pit; and the present invention further ensures the structural stability and force strength of the blocking component by constructing cast concrete, mesh sprayed concrete and structural exterior walls at the sewage pipe outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a construction diagram for plugging the upstream sewage pipe;

[0029] Figure 2 This is the main view of the construction of pumping out the accumulated water in the sewage pipe and plugging the downstream sewage pipe;

[0030] Figure 3 This is a top view of the construction of pumping out the accumulated water in the sewage pipe and plugging the downstream sewage pipe;

[0031] Figure 4 This is a construction diagram for plugging the downstream sewage pipe;

[0032] The meanings of the symbols in the above figure are: 1-retaining wall; 2-cap beam; 3-concrete support; 4-guard piles; 5-air bag; 6-air bag lowering hole; 7-sewage pipe; 8-concrete pouring hole; 9-sandbag; 10-grouting pipe; 11-net sprayed concrete; 12-structural exterior wall; 13-cast concrete; 14-U-shaped steel bar; 15-construction access road. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc., are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0035] Example

[0036] Please refer to the construction method for sealing the deep buried water-rich sewage pipe in the deep foundation pit of the subway station Figures 1 to 4 , which comprises the following steps:

[0037] 1) Blocking of upstream sewage pipe

[0038] According to the position of the sewage pipe 7 in the deep foundation pit, the upstream pipeline position of the sewage pipe is located on the construction access road 15, and then two airbag lowering holes 6 are drilled at the upstream pipeline position by a drilling machine with a diameter of 600mm, and the spacing between the two airbag lowering holes 6 is controlled to be 2m; the airbag 5 is lowered into the sewage pipe 7 through the airbag lowering holes 6, and then the airbag 5 is filled with air; then, a concrete pouring hole 8 is drilled at the upstream pipeline position between the two airbag lowering holes 6 by a drilling machine with a diameter of 600mm, and C30 concrete is poured into the sewage pipe 7 through the concrete pouring holes 8, and the pouring interval is 0.2m. 3 Concrete is vibrated for 1 minute using an inserted vibrator to fill the pipe between the two air bags 5. After filling, the air bag lowering hole 6 and the concrete pouring hole 8 are sealed;

[0039] A drilling machine with a diameter of 600 mm is used for drilling, so that the diameter of the airbag lowering hole and the concrete pouring hole can be controlled to be 600 mm; when using the concrete pouring hole for concrete pouring, a 1m×1m×0.2m wooden box with upper and lower openings can be made on the ground and placed on the concrete pouring hole to facilitate the pouring of concrete;

[0040] 2) Pumping out water from sewage pipes

[0041] Pump out the accumulated water in the downstream sewage pipe 7. When the accumulated water depth is pumped out to 10-15 cm, stack sandbags 9 in the sewage pipe 7 2.5 m upstream of the pile edge of the retaining pile 4 to block the sewage pipe 7. Then drain the accumulated water in the sewage pipe 7 downstream of the sandbags. Before pumping out the accumulated water in the downstream sewage pipe, first check whether there is harmful gas in the sewage pipe. If there is no harmful gas, then proceed with the subsequent construction. If there is harmful gas, then remove the harmful gas before proceeding with the subsequent construction.

[0042] 3) Blockage of downstream sewage pipe

[0043] Sandbags 9 are stacked at the outermost side of the sewage pipe outlet as the outer fetal membrane, and a grouting pipe 10 is reserved so that the outer side of the grouting pipe 10 is pressed by the sandbags 9 and the U-shaped steel bars 14 are welded and fixed to the steel bars in the retaining pile 4. Then, C30 micro-expansive concrete is poured into the sewage pipe 7 through the grouting pipe 10. Every 0.2m 3 Concrete is vibrated for 1 minute using an inserted vibrator. When the concrete strength reaches 80%, the outer sandbag 9 is removed. Then, double-liquid slurry is injected into the pipeline through the grouting pipe 10 to stop water. During the grouting process, the construction workers and supervisors shall monitor the whole process and keep records. After the grouting is completed, the exposed grouting pipe shall be cut off;

[0044] Among them, the grouting pipe is a flower pipe, and a valve is installed on the outside of the grouting pipe. The slurry holes are arranged in a plum blossom shape at intervals of 120 to 180 mm along the wall of the grouting pipe. The positions of the slurry holes are 90 degrees to each other, and the apertures of the slurry holes are 5 to 8 mm. The construction mix ratio of the double liquid slurry is calculated by mass as cement: water glass: water reducer = 378:215:14, and the setting time of the on-site mix ratio experiment is 30s to 60s. The calculation and verification process of the construction mix ratio of the double liquid slurry is that the construction mix ratio of the double liquid slurry is cement slurry: water glass = 1:1 (volume ratio); 0.5m3 of cement slurry is required for each cubic meter of double liquid slurry. 3 , water glass dilution 0.5m 3 ; During construction, 378kg of cement is used for every 0.5 cubic meter of cement slurry, with a water-cement ratio of 1:1; water glass dilution is made according to the original liquid (35be) 1:3 dilution ratio; 215kg of water glass original liquid is required for every 0.5 cubic meter of water glass dilution; at the same time, 14kg of water reducer is added to each cubic meter of double liquid slurry;

[0045] 4) Seal the sewage pipe opening

[0046] Clean the soil and rocks between the retaining piles 4 on both sides of the sewage pipe 7, control the distance between the soil and rock surface downstream between the retaining piles and the outer wall of the retaining piles to be 300mm-400mm, remove the loose soil and rocks remaining between the piles, clean the soil and rocks attached to the pile body, and roughen the pile body concrete, and the roughening needs to chisel out at least 75% of the coarse aggregate on the exposed surface; then chisel out the sewage pipe and the concrete in the pipe at the pipe mouth position to reserve the pouring space for the cast concrete 13, and then lay the cast steel mesh, install the formwork and pour the cast concrete in sequence. After the cast concrete reaches the set strength, it can be demolded for maintenance; after the demolding and maintenance of the cast concrete is completed, C20 mesh sprayed concrete 11 and the structural outer wall 12 are constructed on the outside of the cast concrete;

[0047] Among them, the specific method of laying cast steel mesh is to first implant C20 steel bars on the retaining piles, with a depth of 200mm. After the anchor glue solidifies, a pull-out test is performed; then the cast steel mesh is laid, and the main bars of the cast steel mesh are welded to the steel bars implanted on the retaining piles; the cast steel mesh uses C20 steel bars and C14 steel bars, with a grid size of 150mm×150mm, and the steel bars are welded. The C20 main bars are directly welded to the steel bars implanted inside the retaining piles, and the C14 steel bars are tied to the upper and lower layers of steel mesh;

[0048] The specific method of installing the formwork is to first check and clean the formwork to ensure that the surface of the formwork is flat and smooth, and apply a release agent; then carry out layered and segmented construction at a vertical interval of 3m, and install the formwork in layers and segments; use 18mm thick wooden formwork between piles, use 50mm×70mm square wood with a spacing of 200mm in the vertical direction, and use A48 double-jointed steel pipes for vertical reinforcement with a spacing of 500mm. Pre-insert M12 expansion screws and weld the extended screws, and fix them with butterfly buckles after extending them out of the formwork. Use A48 steel pipe diagonal braces to reinforce the formwork on the outside with a spacing of 1500mm; use sponge strips to plug and compact the bottom of the formwork to prevent concrete from leaking from the bottom;

[0049] The specific method for pouring cast-in-place concrete is to pour C20 cast-in-place concrete in layers. For every 1m of cast-in-place concrete height, use a vibrating rod or rubber hammer to gently vibrate or tap the outside of the formwork to ensure that the concrete sinks evenly to the bottom. After the first layer is poured, pour the second layer. Repeat the vibration and tapping operations to ensure that the concrete is dense and uniform. Concrete pouring should be carried out continuously. If it must be interrupted, the interval time should be shortened as much as possible, and the second layer of concrete should be poured before the first layer of concrete solidifies. The maximum interval time should be determined according to the type of cement used, air temperature and concrete solidification conditions. Generally, if it exceeds 2h, it should be treated as a construction joint.

Claims

1. A construction method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station, characterized in that The steps include: Step (1) Blocking the upstream sewage pipe According to the position of the sewage pipe in the deep foundation pit, the upstream pipeline position is located on the construction access road, and then two air bag lowering holes are drilled at the upstream pipeline position, and the air bag is lowered into the sewage pipe through the air bag lowering holes, and then the air bag is filled with air, and then a concrete pouring hole is drilled at the upstream pipeline position between the two air bag lowering holes, and concrete is poured into the sewage pipe through the concrete pouring hole, so that the concrete fills the pipeline between the two air bags, and after filling, the air bag lowering hole and the concrete pouring hole are blocked; Step (2) Pumping out the water from the sewage pipe Pump out the accumulated water in the downstream sewage pipe. When the accumulated water depth is pumped out to 10-15 cm, place sandbags 2-3 m upstream of the retaining piles in the sewage pipe to block the sewage pipe. Then drain the accumulated water in the sewage pipe downstream of the sandbags. Step (3) Blocking the downstream sewage pipe Sandbags are stacked on the outermost side of the sewage pipe outlet as the outer fetal membrane, and a grouting pipe is reserved so that the outer side of the grouting pipe is pressed by the sandbags and fixed with the steel bars in the retaining piles by welding with U-shaped steel bars. Then, the sewage pipe is fully poured with micro-expansive concrete through the grouting pipe. When the concrete strength reaches 80%, the outer sandbags are removed. Then, double-liquid slurry is injected into the pipe through the grouting pipe to stop water. After the grouting is completed, the exposed grouting pipe is cut off; Step (4) Seal the sewage pipe opening Clean the soil and rocks between the retaining piles on both sides of the sewage pipe, control the distance between the soil and rock surface downstream between the retaining piles and the outer wall of the retaining piles to 300 mm to 400 mm, then chisel out the sewage pipe and the concrete inside the pipe at the pipe mouth to reserve space for pouring cast-in-place concrete, then lay cast-in-place steel mesh, install formwork and pour cast-in-place concrete in sequence. After the cast-in-place concrete reaches the set strength, the formwork can be removed for maintenance.

2. The method for plugging a deep-buried sewage pipe in a deep foundation pit of a subway station according to claim 1, characterized in that: In the step (1), the diameters of the airbag lowering holes and the concrete pouring holes are 500 to 750 mm, and the distance between the two airbag lowering holes is 1.5 to 2.5 m.

3. The method for plugging a deep-buried sewage pipe in a deep foundation pit of a subway station as claimed in claim 1, characterized in that: In step (2), before draining the accumulated water in the sewage pipe, first check whether there is harmful gas in the sewage pipe. If there is no harmful gas, subsequent construction can be carried out; if there is harmful gas, the harmful gas should be removed before subsequent construction.

4. The method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station as claimed in claim 1, characterized in that: In the step (3), the grouting pipe is a flower pipe, a valve is installed on the outside of the grouting pipe, and the slurry outlet holes are arranged in a plum blossom shape at intervals of 120 to 180 mm along the wall of the grouting pipe. The positions of the slurry outlet holes are 90 degrees to each other, and the diameter of the slurry outlet holes is 5 to 8 mm.

5. The method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station as claimed in claim 1, characterized in that: In the step (3), the construction mix ratio of the double liquid slurry is, by mass, cement: water glass: water reducing agent = 378:215:

14.

6. The method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station as claimed in claim 1, characterized in that: In the step (3), the micro-expansive concrete is C30 micro-expansive concrete. When pouring the micro-expansive concrete, every 0.15 to 0.25 m 3 The concrete is vibrated using an inserted vibrator.

7. The method for plugging a deep-buried sewage pipe in a deep foundation pit of a subway station as claimed in claim 1, characterized in that: In step (4), after the soil and rocks between the retaining piles on both sides of the sewage pipe are removed, the soil and rocks attached to the pile body should also be cleaned, and the pile body concrete should be roughened. The roughening process requires that at least 75% of the coarse aggregate is chiseled out on the exposed surface.

8. The method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station as claimed in claim 1, characterized in that: In the step (4), the casting steel mesh is laid by first implanting steel bars on the retaining piles, with the implantation depth being 150 to 250 mm, and then the casting steel mesh is laid, and the main bars of the casting steel mesh are welded to the steel bars implanted on the retaining piles.

9. The method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station as claimed in claim 1, characterized in that: In the step (4), the cast concrete is C20 concrete, and the cast concrete is gently vibrated or tapped on the outside of the formwork every 0.5 to 1.2 m of pouring height.

10. The method for plugging a deep-buried water-rich sewage pipe in a deep foundation pit of a subway station according to any one of claims 1 to 9, characterized in that: In the step (4), after the cast concrete is removed from the formwork and cured, C20 mesh sprayed concrete and the structural exterior wall are constructed on the outside of the cast concrete.

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