Device and process for pit bottom piping plugging

Abstract

The invention relates to a device and process for pit bottom piping plugging. The device comprises a grouting pipe, a grouting system and a bag section. The bag section is fixed on the grouting pipe through a flange and is 5m away from the bottom end of the grouting pipe; the grouting pipe is connected with a grouting system, the bag section is of a double-layer composite structure, the outer layer is a high-strength polyester woven layer, and the lining is a butyl rubber sealing film; the outer diameter of the bag section in the folded state is 20-30 mm, the bag section is evenly expanded to 300-500 mm after grouting, the channel wall is extruded after expansion, and fast-setting grout is prevented from flowing upwards. The method is suitable for the pit bottom piping of the ultra-deep foundation pit, and is particularly suitable for the pit bottom piping working condition with the leakage amount larger than 10 m < 3 > / h.

Description

Technical Field

[0001] The present invention relates to the technical field of deep foundation pit construction, and in particular to a process and device for blocking pipe bursts at the bottom of a pit, which is particularly suitable for applications with a leakage greater than 10m 3 / h deep foundation pit bottom pipe leakage blocking operation. Background Art

[0002] During the foundation pit construction process, pipe bursts at the bottom of the pit are one of the common risks of deep foundation pits. When the seepage channel is eroded to a certain extent, the amount of water and sand gushing out is very large. During grouting, the slurry is flushed out of the channel, making it very difficult to seal. Traditional methods mainly use stabilization measures such as recharge and compressed concrete. The recharge method requires continuous injection of an equal amount of water to maintain pressure balance, but it consumes tens of thousands of cubic meters of water resources; the compressed concrete method mainly relies on pouring concrete for sealing, which requires large-scale equipment support and a solidification period of more than 72 hours, delaying the construction period and increasing the risk of landslides.

[0003] Traditional plugging methods have significant defects:

[0004] 1. Recharge method: It requires continuous injection of tens of thousands of cubic meters of water to maintain pressure balance, which consumes huge water resources and cannot cure pipe bursts;

[0005] 2. Pressed concrete method: Relying on large equipment to pour concrete, the setting period exceeds 72 hours, delaying the construction period and increasing the risk of landslides;

[0006] 3. Single-liquid grouting method (such as patent document CN104631478A): The slurry is easily dispersed by gushing water, the curing speed is slow, and the plugging success rate is low;

[0007] 4. Double liquid bag sealing method (such as patent document CN106320728A): It is only applicable to basement floor holes. The bag has a limited expansion range and cannot adapt to the complex leakage channels of deep foundation pits. It also lacks subsequent enhanced sealing measures.

[0008] Therefore, there is an urgent need for a plugging device and process that is easy to operate, fast and efficient, and adaptable to complex piping channels. Summary of the Invention

[0009] The present invention aims to solve the problems of water resource waste, long construction period, low plugging success rate and poor adaptability existing in traditional methods. A device and process for plugging pipe bursts at the bottom of a pit are proposed. First, a flat vibrator is used to vibrate a grouting pipe with a bag into a leakage channel for a certain distance, and then the grouting system is connected to start grouting. During the grouting process, the bag is grouted and expanded, and the channel is squeezed to block the upwelling of the fast-setting grouting liquid, thereby effectively plugging the gushing channel, thereby achieving the treatment of water gushing from the foundation pit.

[0010] To achieve the above-mentioned purpose, the technical solution of the present invention is: a device for sealing pit bottom pipe bursts, comprising a grouting pipe, a grouting system and a bladder section; the bladder section is fixed to the grouting pipe through a flange, 5m away from the bottom end of the grouting pipe; the grouting pipe is connected to the grouting system, and the bladder section adopts a double-layer composite structure, the outer layer is a high-strength polyester woven layer, and the inner layer is lined with a butyl rubber sealing film; the outer diameter of the bladder section in the folded state is 20-30mm, and after grouting, it expands evenly to 300-500mm, and after expansion, it squeezes the channel wall to block the upward flow of fast-setting slurry.

[0011] Furthermore, the grouting system adopts a hydraulic dual-fluid grouting pump or a polyurethane grouting pump.

[0012] Furthermore, the grouting pipe is composed of a DN50 galvanized steel pipe and a DN20 galvanized steel pipe of the bag section connected by an adapter.

[0013] Furthermore, the grouting system is equipped with a dual-channel switching valve, which can control the cement-water glass dual slurry ratio at 3:1; the grouting flow rate of the polyurethane grouting pump is 50L / min.

[0014] A process for blocking a pit bottom piping burst, using the above-mentioned device for blocking a pit bottom piping burst, comprises the following steps:

[0015] Step 1: Assemble the grouting pipe with the bag section and vibrate the grouting pipe into the leakage channel using a flat plate vibrator so that the bag section is 5m away from the grouting surface and the pipe end is more than 1.5m beyond the grouting outlet;

[0016] Step 2: Connect the grouting system and inject fast-setting slurry into the leakage channel. The fast-setting slurry is a cement-water glass two-liquid slurry or an oil-soluble two-component polyurethane;

[0017] Step 3: Connect the grouting system and inject cement slurry into the bag section to expand the bag to a diameter of 300-500mm, squeezing the channel wall to prevent the slurry from rising;

[0018] Step 4: After the main channel is plugged, double-liquid slurry is injected within a radius of 2m centered on the piping point to strengthen the plugging.

[0019] Furthermore, in step 3, the water:cement:bentonite ratio of the cement mixture is 0.6:1:0.03, and the grouting pressure is controlled at 0.5-1 MPa.

[0020] Furthermore, in step 4, if cement-water glass two-liquid slurry is injected, the ratio is 3:1, and the curing time is ≤60s; if oil-soluble two-component polyurethane is injected, the mass ratio of A / B components is 10:1, and the curing time is ≤20s.

[0021] Furthermore, in step 4, the double-liquid slurry for enhanced plugging is a cement-water glass double-liquid slurry with a ratio of 3:1 and a curing time of ≤60s.

[0022] The beneficial effects of the present invention are:

[0023] 1. Improve the effect of traditional grouting: Through the use of fast-setting slurry (curing within 1 minute or 20 seconds) and the physical barrier of the bag, the problems of slow curing and easy dispersion of slurry in traditional methods are solved, and the construction period is greatly shortened. The addition of the bag belt section can prevent the slurry from surging and improve the plugging effect compared with traditional grouting.

[0024] 2. High reliability: The double-layer bag structure enhances sealing, and the later stage of grouting is strengthened to expand the sealing range and reduce the risk of recurrence.

[0025] 3. Strong adaptability: Flat vibrator-assisted implantation ensures that the grouting pipe penetrates deep into the channel, and the bag has a large expansion range (300-500mm), adapting to piping paths of different sizes;

[0026] 4. Save processing costs: Compared with the re-injection method and the pressed concrete method, it saves water resources and large equipment costs, and the cost of double-liquid slurry materials is low; the traditional re-injection water or pressed concrete costs are very high, this method uses cement-water glass double-liquid slurry, which can greatly reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a cross-sectional view of the device for blocking piping at the bottom of a pit according to the present invention. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, an embodiment of the present invention provides a device and process for blocking pipe bursts at the bottom of a pit, including a grouting pipe 1, a grouting system 2, and a bag section 3.

[0030] The bag section 3 is fixed on the grouting pipe 1 through a flange, 5m away from the bottom end of the grouting pipe; the grouting pipe 1 is connected to the grouting system 2, and the bag section adopts a double-layer composite structure, with a high-strength polyester woven layer on the outer layer and a butyl rubber sealing film lined on the inner layer; the outer diameter of the bag section 3 in the folded state is 20-30mm, and it expands evenly to 300-500mm after grouting. After expansion, it squeezes the channel wall to block the upward flow of the fast-setting slurry.

[0031] Preferably, the grouting system 2 adopts a hydraulic dual-fluid grouting pump or a polyurethane grouting pump.

[0032] Preferably, the grouting pipe is composed of a DN50 galvanized steel pipe and a DN20 galvanized steel pipe of the bag section connected by an adapter.

[0033] Preferably, the grouting system 2 is equipped with a dual-channel switching valve, which can control the cement-water glass dual slurry ratio at 3:1; the grouting flow rate of the polyurethane grouting pump is 50L / min.

[0034] Pipe bursting at the bottom of a pit is one of the common risks of deep foundation pits. When the seepage channel is washed to a certain extent, a large amount of water and sand will burst out. During grouting, the slurry will be flushed out of the channel, making it very difficult to seal. Many projects adopt stabilization measures such as backfilling and concrete compression, resulting in huge economic losses. The present invention provides an economical and effective sealing solution. First, a flat vibrator is used to vibrate a grouting pipe with a bag into the seepage channel for a certain distance, and then the grouting system is connected to start grouting. During the grouting process, the bag is grouted and expanded to block the upwelling of the fast-setting grouting liquid by squeezing the channel, thereby effectively sealing the water gushing channel. The grouting liquid can be a 3:1 cement-water-glass two-liquid slurry, and the curing time is controlled to be less than 1 minute. In winter, the curing can be accelerated by heating the mixing water. When the amount of water gushing is large, an oil-soluble two-component polyurethane can also be used to control the curing time to be less than 20 seconds. Cement slurry is used for grouting in the bag, and the bag adopts a non-expanding circular structure with a diameter of 300-500mm after expansion. After the gushing channel is sealed, double liquid grouting is performed on the surrounding 2m area to enhance the sealing effect. This invention is suitable for the bottom pipe burst of ultra-deep foundation pits, especially for the case where the leakage volume is greater than 10m 3 / h pit bottom piping condition.

[0035] This process uses a bag fixed on the grouting pipe. The bag is fixed at a distance of 5m from the grouting surface. Grouting and hole expansion are carried out inside the bag to block the upwelling of the fast-setting slurry, thereby better achieving the purpose of plugging leaks.

[0036] The grouting pipe uses a DN50 galvanized steel pipe, and in the bag section, a DN20 galvanized steel pipe is used, connected with an adapter.

[0037] The bag is fixed to the DN20 galvanized steel pipe through a flange. It adopts a double-layer composite structure with a high-strength polyester braided layer on the outer layer and a butyl rubber sealing film lined on the inner layer.

[0038] The outer diameter of the bag in the folded state is 20-30mm, and it expands evenly to 300-500mm after grouting. After expansion, it squeezes the channel wall to block the upward flow of the fast-setting slurry.

[0039] The grouting system is selected according to different working conditions. If cement-water glass dual-liquid slurry is injected, a hydraulic dual-liquid grouting pump is selected with a maximum grouting flow of 90L / min. It uses a dual-channel switching valve and can accurately control the ratio of the dual-liquid slurry at 3:1, ensuring that the slurry solidification time is within 1 minute; if oil-soluble two-component polyurethane is injected, a polyurethane grouting pump is selected with a grouting flow of 50L / min. After the slurry enters the water gushing channel, foaming and solidification are completed within 20 seconds.

[0040] Grouting has the following steps: ① Install the bladder bag on the galvanized pipe; ② Use a flat vibrator to vibrate the grouting pipe to the designated position; ③ Connect the grouting system; ④ Grouting, when the quick-setting slurry is observed to surge, inject grouting into the bladder bag to expand it to 30-50mm; ④ Continue grouting, after the water gushing treatment is completed, inject double-liquid slurry within 2m of the water gushing point to enhance the sealing effect.

[0041] The method of use of the present invention is as follows:

[0042] 1. Construction Process

[0043] ① Preliminary preparation: assemble the grouting pipe (1) and the bag section (2), and connect the grouting system (3);

[0044] ②Pipe implantation: Use a flat plate vibrator to vertically vibrate the grouting pipe into the piping channel until the pipe end is more than 1.5m beyond the piping outlet;

[0045] ③ Channel blocking: switch the grouting pipeline and inject fast-setting slurry into the channel:

[0046] ④ Bag grouting: Start the grouting pump and inject pure cement slurry (water-cement ratio 0.6:1) into the bag section. The pressure is controlled at 0.5-1MPa until the bag expands to the designed diameter (300-500mm);

[0047] Conventional working conditions: cement-water glass two-liquid slurry (cement slurry:water glass=3:1), field test curing time ≤60s;

[0048] Large water inrush condition: inject oil-soluble polyurethane (A / B component mass ratio 10:1), curing time ≤ 20s;

[0049] ⑤ Strengthen the plugging: After the main channel is plugged, double-liquid grouting reinforcement is carried out in the area with a radius of 2m centered on the pipe burst point.

[0050] The present invention is not limited to the above embodiments. Any adjustment to the bag material, slurry ratio, and grouting pressure within the spirit and principles of the present invention shall fall within the protection scope of the present invention.

Claims

1. A device for blocking piping at the bottom of a pit, characterized by: It includes a grouting pipe, a grouting system and a bladder section; the bladder section is fixed on the grouting pipe through a flange, 5m away from the bottom end of the grouting pipe; the grouting pipe is connected to the grouting system, and the bladder section adopts a double-layer composite structure, the outer layer is a high-strength polyester woven layer, and the inner layer is lined with a butyl rubber sealing film; the outer diameter of the bladder section in the folded state is 20-30mm, and after grouting, it expands evenly to 300-500mm, and after expansion, it squeezes the channel wall to block the rapid-setting slurry from flowing upward.

2. The device for blocking piping at the bottom of a pit according to claim 1, characterized in that: The grouting system adopts a hydraulic double-fluid grouting pump or a polyurethane grouting pump.

3. The device for blocking piping at the bottom of a pit according to claim 1, characterized in that: The grouting pipe is composed of a DN50 galvanized steel pipe and a DN20 galvanized steel pipe of the bag section connected by an adapter.

4. The device for blocking piping at the bottom of a pit according to claim 1, characterized in that: The grouting system is equipped with a dual-channel switching valve, which can control the cement-water glass dual slurry ratio at 3:1; the grouting flow rate of the polyurethane grouting pump is 50L / min.

5. A process for blocking a pipe burst at the bottom of a pit, using the device for blocking a pipe burst at the bottom of a pit according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Assemble the grouting pipe with the bag section and vibrate the grouting pipe into the leakage channel using a flat plate vibrator so that the bag section is 5m away from the grouting surface and the pipe end is more than 1.5m beyond the grouting outlet; Step 2: Connect the grouting system and inject fast-setting slurry into the leakage channel. The fast-setting slurry is a cement-water glass two-liquid slurry or an oil-soluble two-component polyurethane; Step 3: Connect the grouting system and inject cement slurry into the bag section to expand the bag to a diameter of 300-500mm, squeezing the channel wall to prevent the slurry from rising; Step 4: After the main channel is plugged, double-liquid slurry is injected within a radius of 2m centered on the piping point to strengthen the plugging.

6. The process for blocking piping at the bottom of a pit according to claim 5, characterized in that: In step 3, a cement mixture slurry of water:cement:bentonite is injected at a ratio of 0.6:1:0.03, and the grouting pressure is controlled at 0.5-1 MPa.

7. The process for blocking piping at the bottom of a pit according to claim 5, characterized in that: In step 2, if cement-water glass two-liquid slurry is injected, the ratio is 3:1 and the curing time is ≤60s; if oil-soluble two-component polyurethane is injected, the A / B component mass ratio is 10:1 and the curing time is ≤20s.

8. The process for blocking piping at the bottom of a pit according to claim 5, characterized in that: In step 4, the double liquid slurry for strengthening the plugging is cement-water glass double liquid slurry, the ratio of which is 3:1, and the curing time is ≤60s;.

Images