Deep foundation pit pressure-bearing water pipe gushing treatment structure

Abstract

The utility model discloses a deep foundation pit pressure-bearing water pipe surge treatment structure which comprises a stratum and a piping occurrence point, and a steel casing is inserted in the stratum and is coaxial with the piping occurrence point. The utility model relates to the technical field of deep foundation pit foundations, in the beginning of piping, a cotton quilt is adopted as an inverted filter material for preliminary water stopping, then a steel casing is pressed above a piping point to form a cofferdam, gravels are laid around the steel casing, sand bags with a certain height are piled up, and leakage piping at the bottom opening of the casing is prevented; phosphoric acid and water glass mixed slurry is injected into the piping occurrence position in the steel casing, the height of the steel casing is increased according to the actual situation, water pressure is balanced, a hole is drilled outside a pit, cement and water glass mixed slurry is injected, the slurry is solidified to improve the stratum strength, a water-resisting layer is formed, dangerous cases are rapidly and effectively controlled, the treatment method is rapid and efficient, relapse is not prone to occurring, and the method is worthy of popularization and application. And the safety of the construction process is effectively ensured.

Description

Technical Field

[0001] This utility model relates to the field of deep foundation pit technology, specifically a structure for treating confined water seepage in deep foundation pits. Background Technology

[0002] With societal development, surface space is becoming increasingly scarce, making underground space development an inevitable trend, with foundation pits becoming larger and deeper. Therefore, deep foundation pit construction faces more complex problems, one of which is piping. Piping frequently occurs when excavating into sandy or silty soil layers rich in confined water. The water flow carries away soil particles, reducing the soil strength and threatening the safety of the foundation pit and surrounding buildings. Therefore, taking timely and effective measures when piping occurs is crucial.

[0003] Currently, common methods for dealing with piping include injecting cement grout around the piping point. After the grout solidifies, the formation strength increases and permeability decreases, effectively sealing the piping. Alternatively, a filter well can be constructed, with boulders or gravel placed at the piping point to reduce the water pressure. Both of these methods are effective for piping under low water pressure. However, when the formation is rich in confined water and the flow is rapid and large, injecting cement grout outside the well will result in it being washed away by the water flow, failing to stop the flow. The second method relies on experience, is prone to recurrence, requires on-site monitoring, and poses safety hazards.

[0004] While existing technologies may already offer solutions to the aforementioned problems, this case aims to provide an alternative or replacement technical solution. Utility Model Content

[0005] To address the problems mentioned in the background art, this utility model provides the following technical solution: a structure for treating confined water piping in deep foundation pits, comprising:

[0006] The stratum and the point of piping occurrence, wherein a steel casing is inserted on the stratum and coaxial with the point of piping occurrence;

[0007] The grouting pipe is inserted into the stratum and located inside the steel casing;

[0008] The filter material is filled between the steel casing and the grouting pipe in the pit;

[0009] A crushed stone cushion layer, wherein the crushed stone cushion layer is set on the stratum with a steel casing as the center;

[0010] Soil bags, wherein the soil bags are placed on the gravel cushion layer with the steel casing as the center;

[0011] Multiple external grouting pipes are inserted into the stratum through the soil bag and the crushed stone cushion layer, and the multiple external grouting pipes are arranged in a circular array at equal intervals with the steel casing as the center.

[0012] The first double grout is filled into the grouting pipe in the pit;

[0013] The second double grout is filled into the plurality of said pit external grouting pipes.

[0014] Preferably, the steel casing is a hollow structure, with interfaces at both ends, and the steel casing is inserted into the formation to a depth of not less than 3m.

[0015] Preferably, the steel casing has a height of 2.5m, a diameter that is 1.5m larger than the diameter of the piping point, and a wall thickness of 5mm.

[0016] Preferably, the crushed stone cushion layer has a crushed stone particle size of 40-150mm and a thickness of not less than 0.5m.

[0017] Preferably, the height of the soil bag is not less than 1m.

[0018] Preferably, the spacing between the plurality of external grouting pipes and the steel casing is 1.5m.

[0019] Preferably, the first dual slurry is a solution of phosphoric acid and water glass.

[0020] Preferably, the first slurry is a cement and water glass solution.

[0021] Beneficial effects

[0022] This utility model provides a structure for treating piping in deep foundation pits with confined water. Compared with existing technologies, it has the following advantages: At the initial stage of piping, cotton quilts are used as a filter material for initial water stoppage. Then, a steel casing is pressed in above the piping point to form a cofferdam. Crushed stones are laid around the steel casing, and sandbags of a certain height are piled up to prevent leakage and piping at the bottom of the casing. A mixture of phosphoric acid and water glass is injected into the piping point inside the steel casing. The height of the steel casing is increased according to the actual situation to balance the water pressure. Holes are drilled outside the pit, and a mixture of cement and water glass is injected. The solidification of the grout increases the soil strength, forming a water-resistant layer, quickly and effectively controlling the danger. This treatment method is fast, efficient, and less prone to recurrence, effectively ensuring the safety of the construction process. It has advantages such as speed, efficiency, good water-stopping effect, strong operability, and ease of implementation, providing technical support for piping treatment. Attached Figure Description

[0023] Figure 1This is a schematic diagram of the main sectional view of a deep foundation pit pressurized water piping treatment structure according to the present invention;

[0024] Figure 2 This is a top view schematic diagram of a deep foundation pit pressurized water piping treatment structure according to the present invention;

[0025] In the diagram: 1. Stratum, 2. Crushed stone cushion layer, 3. Grouting pipe outside the pit, 4. Soil bag, 5. Steel casing, 6. Grouting pipe inside the pit, 7. Filter material, 8. Piping point. Detailed Implementation

[0026] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0027] Example: Please refer to Figure 1-2 A structure for treating confined water piping in deep foundation pits, comprising:

[0028] The stratum and the point where piping occurs, with a steel casing inserted on the stratum and coaxial with the point where piping occurs;

[0029] The filter material is filled between the steel casing and the grouting pipe in the pit.

[0030] It should be noted that filter material is filled at the location of piping to achieve initial water stoppage. The filter material can be a cotton quilt. A steel casing is inserted into the formation, with the filter material inside the steel casing to isolate the pressurized water and prevent the piping from spreading further. During the installation of the steel casing, the center of the steel casing should be aligned with the location of the piping, and real-time monitoring should be conducted to ensure that the steel casing is vertical.

[0031] Crushed stone cushion layer, which is set on the stratum with a steel casing as the center;

[0032] Soil bags are placed on the gravel cushion layer with a steel casing as the center.

[0033] It should be noted that the crushed stone cushion layer is composed of crushed stone particles. The crushed stone cushion layer is laid and compacted within a 2.5m range of the outer diameter of the steel casing, and soil bags are piled on top of the crushed stone cushion layer.

[0034] The grouting pipe is inserted into the stratum and located inside the steel casing.

[0035] Multiple external grouting pipes are inserted into the stratum through the soil bags and crushed stone cushion layer, and the multiple external grouting pipes are arranged in a circular array at equal intervals with the steel casing as the center.

[0036] The first double grout is filled into the grouting pipe in the pit;

[0037] The second double grout is filled into multiple external grouting pipes;

[0038] It should be noted that the first double grout is injected into the steel casing through the grouting pipe inside the pit and under the cotton quilt. Grouting can be stopped only when there is no obvious water flow. The steel casing is raised according to the site conditions to make it 1m above the pressurized water level to balance the water pressure. The second double grout is injected into multiple grouting pipes outside the pit.

[0039] As a preferred and further option, the steel casing is a hollow structure, with interfaces at both ends, and the depth of the steel casing inserted into the formation is not less than 3m.

[0040] It should be noted that the structure and method of splicing two steel pipes using an interface is existing technology and is not an innovation of this technical solution. It will not be elaborated here. You can refer to a socket structure for steel pipe connection with publication number CN103953807B, which can extend the steel casing by connecting the interfaces of two steel casings.

[0041] As a preferred and further option, the height of the steel casing is 2.5m, the diameter of the steel casing is 1.5m larger than the diameter of the piping point, and the wall thickness of the steel casing is 5mm.

[0042] Preferably, the crushed stone cushion layer has a crushed stone particle size of 40-150mm and a thickness of not less than 0.5m;

[0043] As a preferred and further option, the height of the soil bag shall not be less than 1m;

[0044] As a preferred and further option, the spacing between the multiple external grouting pipes and the steel casing is 1.5m;

[0045] As a preferred and further option, the first dual slurry is a phosphoric acid and water glass solution, wherein slurry A is a 15% phosphoric acid solution and slurry B is a water glass solution with a Baume degree of 20, and slurry A and slurry B are mixed in a 1:1 ratio.

[0046] As a preferred and further option, the first grout is a cement and water glass solution. Grout A is made of 42.5 grade ordinary Portland cement with a water-cement ratio of 1:1; Grout B is a water glass solution with a Baume degree of 30. Grout A and grout B are mixed in a 1:1 ratio.

[0047] Working principle and method:

[0048] Step 1, as shown in the attached document Figure 1 and attached Figure 2 As shown, after piping is discovered, the location of the piping is immediately determined, and cotton quilts are filled into the area where the piping occurs as a filter material to achieve the purpose of initial water stoppage.

[0049] Step two, as shown in the attached document. Figure 1 and attached Figure 2 As shown, a steel casing is driven into the location where piping occurs. During the driving process, the center of the steel casing should be aligned with the location of the piping. At the same time, real-time monitoring should be conducted to ensure that the steel casing is vertical. The depth of the steel casing should be no less than 3m, the height of the steel casing should be 2.5m, the diameter should be 1.5m larger than the diameter of the piping point, and the wall thickness should be 5mm.

[0050] Step 3, as shown in the attached document Figure 1 and attached Figure 2 As shown, a crushed stone cushion layer is laid and compacted within a 2.5m radius of the outer diameter of the steel casing. Soil bags are piled on top of the crushed stone cushion layer. The crushed stone has a particle size of 40-150mm, uniform gradation, and a thickness of not less than 0.5m. The pile height of the soil bags is not less than 1m.

[0051] Step 4: Inject phosphoric acid and water glass grout into the piping point inside the steel casing through the grouting pipe inside the pit until there is no obvious water inflow. The grout materials are phosphoric acid and water glass solutions. A 15% phosphoric acid solution is used as grout A, and a 20 Baume water glass solution is used as grout B. Grout A and grout B are mixed in a 1:1 ratio. Then, raise the steel casing until it is 1m above the pressurized water level to balance the water pressure.

[0052] Step 5: Multiple grouting holes are laid out circumferentially around the steel casing for inserting multiple external grouting pipes. These external grouting pipes are positioned 1.5m radially from the steel casing and evenly arranged in a quincunx pattern. A ZLG-1200 drilling rig is used to drill holes with a diameter of 80mm and a vertical accuracy of less than 1%. The external grouting material for the steel casing consists of cement and water glass solution. 42.5 grade ordinary Portland cement is used, with a water-cement ratio of 1:1, to form grout A. A water glass solution with a Baume degree of 30 is used as grout B. Grout A and grout B are mixed in a 1:1 ratio.

[0053] Step 6: Grout in 3 sections every 1 meter from the bottom of the grouting hole upwards, with each section being 33cm high. After each section is completed, pull it up 33cm and grout again until it reaches a height of 2m below the ground. The grouting pressure is 0.2-1.2MPa, adjusted according to the actual grouting effect on site. The grouting pressure in a single hole is increased to the final pressure and grouting is continued for more than 10 minutes to complete the grouting.

[0054] Among them, a three-way valve is set at the grout outlet of the grouting machine, and grout A and grout B are injected through different grouting pipes, and finally mixed and injected into the formation in the three-way valve.

[0055] Step 7: After the grouting volume and pressure reach the design values, the external grouting pipe and the internal grouting pipe need to be lifted quickly, evenly, and at certain intervals. Then, the external grouting pipe and the internal grouting pipe should be cleaned.

[0056] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A structure for treatment of a confined water pipe gushing in a deep foundation pit, characterized by, It comprises: a stratum (1) and a piping point (8), a steel casing (5) is inserted on the stratum (1) and coaxial with the piping point (8); an in-pit grouting pipe (6) is inserted on the stratum (1) and located inside the steel casing (5); a filter material (7) is filled between the steel casing (5) and the in-pit grouting pipe (6); a gravel cushion (2) is arranged on the stratum (1) with the steel casing (5) as the center; a soil bag (4) is arranged on the gravel cushion (2) with the steel casing (5) as the center; a plurality of out-pit grouting pipes (3) are inserted on the stratum (1) through the soil bag (4) and the gravel cushion (2), and the plurality of out-pit grouting pipes (3) are arranged in a circular array at equal distances with the steel casing (5) as the center; a first double slurry is filled in the in-pit grouting pipe (6); a second double slurry is filled in the plurality of out-pit grouting pipes (3).

2. The structure for treatment of water pipe gushing of confined water in a deep foundation pit according to claim 1, characterized in that, The steel casing (5) is a hollow structure, both ends of the steel casing (5) are provided with interfaces, and the depth of the steel casing (5) inserted into the stratum (1) is not less than 3m.

3. The structure for treatment of water pipe gushing of confined water in a deep foundation pit according to claim 1, characterized in that, The height of the steel casing (5) is 2.5m, the diameter of the steel casing (5) is 1.5m larger than the diameter of the piping point (8), and the wall thickness of the steel casing (5) is 5mm.

4. The structure for treatment of water pipe gushing of confined water in a deep foundation pit according to claim 1, characterized in that, The gravel size of the gravel cushion (2) is 40-150mm, and the thickness of the gravel cushion (2) is not less than 0.5m.

5. The structure for treatment of water pipe gushing of confined water in a deep foundation pit according to claim 1, characterized in that, The height of the soil bag (4) is not less than 1m.

6. The structure for treatment of water pipe gushing of confined water in a deep foundation pit according to claim 1, wherein The spacing between the plurality of out-pit grouting pipes (3) and the steel casing (5) is 1.5m.

7. The structure for treatment of water pipe gushing of confined water in a deep foundation pit according to claim 1, wherein The first double slurry is phosphoric acid and water glass solution.

8. The structure for treatment of water pipe gushing of confined water in a deep foundation pit according to claim 1, wherein The first double slurry is cement and water glass solution.

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