A method for eliminating the need for chiseling inside a lattice column in a foundation pit

Abstract

A method for eliminating the need for chiseling within a lattice column in a foundation pit is characterized by installing a water bag inside the lattice column. After the concrete is poured into the lower column piles, water is injected into the water bag. Then, fluidized solidified soil is filled between the lattice column and the pile holes containing the column. After excavation, the outlet of the water bag is opened to allow the water to flow away, and the water bag is removed, thus eliminating the need for chiseling the lattice column. The water bag includes an outer layer, an inner layer, and inlet / outlet ports. The outer layer has bolt fixing holes for connection to the angle steel of the lattice column. The inner layer is made of a deformable material that expands when filled with water. The inlet / outlet ports are located at the top and bottom of the water bag, and the number of inlet / outlet ports is determined by the rate of water inflow and outflow. The bags designed in this invention can be connected in series to length according to actual needs, and can be disassembled and reused, which has the characteristics of strong engineering adaptability and reusability; by filling the gap between the grid column and the pile hole with fluid solidified soil, the manual chiseling of the gap between the pile and the hole can be avoided; by using water filling, the amount of concrete used is reduced, which is ecological and environmentally friendly and also greatly reduces costs.

Description

Technical Field

[0001] This invention relates to the field of foundation pit engineering, and in particular to a method for removing lattice columns in foundation pit engineering. Background Technology

[0002] Underground engineering construction inevitably involves foundation pit excavation. According to current regulations, foundation pits with a single span greater than 20m require the installation of pile foundations to support their self-weight. The most common form of pile foundations is a lattice column at the top and reinforced concrete at the bottom, with the upper and lower sections connected by lattice columns inserted into the reinforced concrete at a certain depth. This design fully utilizes the load-bearing capacity of the lower piles, while the upper lattice column, a hollow steel structure, allows for easy passage of the reinforcing steel in the concrete support, forming a complete load-bearing node. It also allows for welding to the lattice column for easy splicing. However, during construction, the entire upper structure of the pile hole, i.e., the upper lattice column, is often filled with plain concrete. After excavation, the concrete inside and outside the lattice column needs to be manually removed to allow it to function. This removal process is time-consuming and is a significant reason why the foundation pit support may not function promptly. Furthermore, the removal generates considerable noise, one of the main sources of noise during foundation pit construction, negatively impacting the surrounding environment, worker health, and safety. Furthermore, the removal process can only be done manually, which is very costly. Therefore, there is an urgent need to improve the method of removing lattice columns.

[0003] Currently, some technicians have proposed a method for quickly cleaning lattice columns (CN 221461609 U), which involves filling the inside of the lattice column with foam adhesive to reduce the need for concrete removal. However, this method only fills the inside; the external concrete still needs to be removed. Furthermore, the foam adhesive filling still requires manual excavation and poses a significant fire risk, as lattice columns often require welding during construction, and the high temperatures of welding can easily ignite the foam adhesive. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for eliminating the need for chiseling away lattice columns in foundation pit engineering, avoiding the removal of concrete and overcoming the shortcomings of existing methods. This invention involves installing a water-filled bag on the lattice column. After the lower column pile is poured with concrete, water is injected into the bag, filling the lattice column completely. Then, fluidized solidified soil is filled between the lattice column and the pile hole to seal the hole. After excavation, the inlet and outlet of the water-filled bag are opened to allow the water to drain away, and the bag is removed and reused. This achieves the elimination of the need for chiseling away lattice columns. This invention has the advantages of low cost, reusability, and environmental friendliness, and is particularly suitable for situations where chiseling away concrete is not required for lattice columns in foundation pit engineering.

[0005] This invention provides a method for eliminating the need for chiseling lattice columns in foundation pit engineering. The core of this method involves installing a water bag inside the lattice column. After the concrete is poured into the lower pile of the lattice column, water is injected into the water bag. Then, fluidized solidified soil is filled between the lattice column and the pile hole containing the column. After excavation, the outlet of the water bag is opened to allow the water to flow away, and the water bag is then removed, thus eliminating the need for chiseling the lattice column. The method specifically includes the following steps:

[0006] Step 1: After completing the connection between the steel reinforcement of the column pile and the lattice column, install the bags in series on the lattice column; the number of bags is greater than or equal to 2.

[0007] Step 2: Hoist the column piles and lattice columns into the pile holes;

[0008] Step 3: Use a guide pipe to pour concrete into the lower part of the column pile;

[0009] Step 4: After the concrete has initially set, fill the bag with water;

[0010] Step 5: After the bag is filled with water, fill the space between the lattice column and the pile hole with fluidized solidified soil;

[0011] Step 6: Remove the soil at the location of the first concrete support and construct the first concrete support.

[0012] Step 7: Remove the first layer of soil, which is at the same height as the first concrete support; drain the water from the bags above ground, and construct the second concrete support in accordance with the method in Step 6.

[0013] Step 8: Remove the second layer of soil, which is at the same height as the second concrete support; drain the water from the bags above ground, and construct the third concrete support using the method described in Step 6.

[0014] Step 9: Repeat the construction of concrete supports, excavation, and drainage of water from the bags, following the same method as steps 6-8, to finally complete the excavation of the foundation pit.

[0015] Preferably, the bag includes an outer bag layer, an inner bag layer, and inlet and outlet ports; the outer bag layer is equipped with bolt fixing holes and is connected to the angle steel of the lattice column by bolts; the inner bag layer is made of deformable material and expands when filled with water; the inlet and outlet ports are located at the top and bottom of the bag, and the number of inlet and outlet ports is determined by the rate of water inflow and outflow.

[0016] Preferably, the multiple bags are connected in series such that the inlet and outlet of adjacent bags are connected.

[0017] Preferably, the compressive strength of the solidified fluidized soil after solidification is less than 4 MPa, so that the excavator can directly remove the solidified fluidized soil during excavation, avoiding manual removal.

[0018] Preferably, the water in the bag is drained by digging an inlet and outlet at the bottom, allowing the water to flow out naturally.

[0019] Preferably, after the water in the bag is drained, the bolts are unscrewed, the empty bag is removed, and it is extracted from the gap in the lattice column, thus achieving manual removal and reuse of the bag.

[0020] Preferably, the outer layer of the bag matches the internal space of the lattice column; the inner layer of the bag is in a naturally contracted state when not filled with water, forming an internal hollow structure that fits the inner side of the lattice column, which can provide a lowering channel for the concrete pouring duct.

[0021] Preferably, the outer layer of the bag is made of high-temperature resistant earthen arch fabric; the inner layer of the bag is made of rubber with high deformability.

[0022] Preferably, after the bag is filled with water, the outer layer of the bag fits into the space inside the lattice column, and the inner layer of the bag is compressed, thereby squeezing the reserved inner cavity structure until it is filled.

[0023] The present invention also provides the application of the above method in foundation pit engineering.

[0024] The present invention has the following technical effects:

[0025] 1. The bags designed in this invention can be connected in series to length according to actual needs, and can be disassembled and reused, which has the characteristics of strong engineering adaptability and reusability.

[0026] 2. This invention avoids the need for manual chiseling of the gap between the pile and the hole by filling the gap between the grid column and the pile hole with fluidized solidified soil.

[0027] 3. This invention utilizes water filling, which reduces the amount of concrete used, is environmentally friendly, and also greatly reduces costs.

[0028] 4. This invention eliminates the need for manual concrete removal, greatly reducing labor costs and improving efficiency; it also avoids noise and improves the construction environment. Attached Figure Description

[0029] Figure 1 This is a diagram of the column pile hoisting process.

[0030] Figure 2 Drawings showing the completion of concrete pouring for the column piles.

[0031] Figure 3 The image shows the bag after it has been filled with water.

[0032] Figure 4 This is a diagram showing the construction of the first support structure.

[0033] Figure 5 To complete the first layer of soil excavation.

[0034] Figure 6 To complete the excavation of the second layer of soil.

[0035] Figure 7 To complete the excavation of the third layer of soil.

[0036] Figure 8 This is a diagram of the lattice column structure before it is filled with water.

[0037] Figure 9 This is a diagram of the lattice column structure after it has been filled with water.

[0038] Figure 10 This is the AA section diagram of the lattice column when it is not filled with water.

[0039] Figure 11 This is the AA section diagram of the lattice column after it has been filled with water.

[0040] The attached diagram is labeled as follows: 1-Ground; 2-Pile hole; 3-Crane; 4-Column pile reinforcement; 5-Lattice column; 6-Concrete; 7-First concrete support; 8-Second concrete support; 9-Third concrete support; 10-Fluidized solidified soil; 21-Angle steel; 22-Gluing plate; 30-Bag; 31-Outer layer of bag; 32-Inner layer of bag; 33-Bolt; 34-Inlet and outlet; 35-Water. Specific Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments.

[0042] Example 1

[0043] This implementation case involves a shopping mall foundation pit project with a depth of 12m, excavated in three layers, each 4m deep. Due to the soft soil area, a support structure of three layers of concrete supports plus diaphragm walls was adopted. To avoid manual removal of the concrete from the column piles, the method of this invention was used. The total length of the column piles is 24m, and the lattice columns are 750mm × 750mm square cross-section steel lattice columns. Each lattice cell is 2m long, and a total of 8 lattice cells are connected in series to achieve concrete removal without the need for manual chiseling of the lattice columns. The main steps include:

[0044] Step 1: After welding the reinforcing bars of the column pile and the lattice column, install the 8 bags in series on the angle steel of the lattice column.

[0045] Step 2: Use a crane to lift the entire column pile into the pile hole.

[0046] Step 3: Use a guide pipe to pour C35 concrete into the lower part of the column pile.

[0047] Step 4: After the concrete has initially set, fill the bag with water at a pressure of 150 kPa.

[0048] Step 5: After the bag is filled with water, fluidized solidified soil is filled between the lattice column and the pile hole. The final compressive strength of the fluidized solidified soil is controlled within 4MPa.

[0049] Step 6: Excavate the soil at the first concrete support to a depth of 1m, and construct the first concrete support with a cross-sectional dimension of 1m high and 0.8m wide.

[0050] Step 7: Remove the first layer of soil, which is 4m thick; excavate the inlet and outlet from the bottom to drain the water from the bags above ground; after the water in the bags is drained, unscrew the bolts, remove the empty bags, and remove the lattice column from the void; and construct the second concrete support, with a cross-section of 1m high and 0.8m wide.

[0051] Step 8: Remove the second layer of soil, which is 4m thick; excavate the inlet and outlet from the bottom to drain the water from the bags above ground; after the water in the bags is drained, unscrew the bolts, remove the empty bags, and remove the lattice column from the void; construct the third concrete support, with a cross-section of 1m high and 0.8m wide.

[0052] Step 9: Remove the third layer of soil, which is 4m thick; excavate the inlet and outlet from the bottom to drain the water from the bags above ground; after the water in the bags is drained, unscrew the bolts, remove the empty bags, and remove the lattice columns from the lattice column vents; finally, the foundation pit excavation is completed.

[0053] The accompanying drawings clearly show the specific locations of the various parts and their interconnections. These illustrations provide visual support for specific embodiments of the present invention, aiding in understanding its technical principles and practical applications.

[0054] Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A method for eliminating the need for chiseling within a lattice column in a foundation pit, characterized in that, A water bag is installed inside the lattice column. After the concrete is poured into the lower pile of the lattice column, water is injected into the water bag. Then, fluidized solidified soil is filled between the lattice column and the pile hole where the lattice column is located. After the soil layer is excavated, the outlet of the water bag is opened to allow the water to flow away, and the water bag is removed, thus achieving the lattice column without chiseling. The specific steps include: Step 1: After completing the connection between the steel reinforcement of the column pile and the lattice column, install the bags in series on the lattice column; the number of bags is greater than or equal to 2. Step 2: Hoist the column piles and lattice columns into the pile holes; Step 3: Use a guide pipe to pour concrete into the lower part of the column pile; Step 4: After the concrete has initially set, fill the bag with water; Step 5: After the bag is filled with water, fill the space between the lattice column and the pile hole with fluidized solidified soil; Step 6: Remove the soil at the location of the first concrete support and construct the first concrete support. Step 7: Remove the first layer of soil, drain the water from the bags above ground, and construct the second layer of concrete support in accordance with the method in Step 6. Step 8: Remove the second layer of soil, drain the water from the bags above ground, and construct the third layer of concrete support in accordance with the method in Step 6. Step 9: Repeat the construction of concrete supports, excavation, and water release from the bags, following the methods in steps 6-8, to finally complete the excavation of the foundation pit.

2. The method according to claim 1, characterized in that, The bag includes an outer layer, an inner layer, and inlet / outlet ports; the outer layer has bolt fixing holes for connection to the angle steel of the lattice column; the inner layer is made of deformable material and expands when filled with water; the inlet / outlet ports are located at the top and bottom of the bag, and the number of inlet / outlet ports is determined by the rate of water inflow and outflow.

3. The method according to claim 2, characterized in that, Multiple bags are connected in series by linking the inlet and outlet of adjacent bags.

4. The method according to claim 1, characterized in that, The compressive strength of the solidified fluidized soil after solidification is less than 4 MPa, so that the excavator can directly remove the fluidized soil during excavation, avoiding manual removal.

5. The method according to claim 2, characterized in that, The water in the bag is drained by digging inlet and outlet at the bottom, allowing the water to flow out naturally.

6. The method according to claim 5, characterized in that, After the water in the bag is drained, the bolts are loosened, the empty bag is removed, and it is pulled out from the gap in the lattice column, thus achieving manual removal and reuse of the bag.

7. The method according to claim 6, characterized in that, The outer layer of the bag matches the internal space of the lattice column; the inner layer of the bag is in a naturally contracted state when not filled with water, forming an internal hollow structure that fits the inside of the lattice column, which can provide a channel for the duct to be lowered for pouring concrete.

8. The method according to claim 2, characterized in that, The outer layer of the bag is made of high-temperature resistant earthen arch fabric; the inner layer of the bag is made of rubber with high deformability.

9. The method according to claim 2, characterized in that, After the bag is filled with water, the outer layer of the bag fits into the space inside the lattice column, and the inner layer of the bag is compressed, thereby squeezing the reserved inner cavity structure until it is filled.

10. The application of the method according to any one of claims 1-9 in foundation pit engineering.

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