Construction method of building slag brick + dry cement, slurry retaining wall

Abstract

The purpose of this invention is to provide a construction method for using construction waste bricks + dry cement and mud slurry for wall protection in soft plastic and fluid plastic strata. This method belongs to the field of pile foundation technology in building construction. The steps are as follows: After borehole collapse, construction waste bricks are placed inside the borehole. A rotary drill bit carries a mixture of dry cement and construction waste to the collapsed area at the bottom of the borehole. First, a conical drill bit statically presses the placed construction waste bricks at the bottom of the borehole. Then, the conical drill bit rotates in the opposite direction, squeezing and expanding the bricks to the collapsed borehole wall in the soft plastic layer. Finally, the conical drill bit touches the bottom, opens the valve, and is raised 2 meters. It then rotates in the forward direction to discharge the mixture from the drill bit. The drill bit repeatedly rises and falls and rotates in the opposite direction at the collapsed area at the bottom of the borehole, expanding and filling the construction waste bricks + dry cement filler to the borehole wall in the soft plastic and fluid plastic layer, forming a layer of construction waste and cement mixed mud slurry wall protection at the collapsed area. The brick-concrete wall protection formed by this invention can effectively resist the lateral pressure exerted on the borehole wall by the plastic and fluid plastic soil layer.

Description

Technical Field

[0001] This invention belongs to the field of pile foundation technology in building construction, specifically relating to a construction method of using slag bricks + dry cement and mud slurry for wall protection in fluid plastic and soft plastic foundations. Background Technology

[0002] Mud-wall bored pile construction is widely used in pile foundation engineering. When drilling rigs encounter thick layers of soft plastic or fluid plastic silt, the conventional approach is to extend the casing, increase the mud consistency, increase the mud specific gravity, and add cement. However, when encountering complex foundations with large areas of interbedded highly sensitive soil and liquefiable soil, the amount of cement used will undoubtedly increase significantly. If the treatment effect does not meet the design requirements, additional measures such as grouting around the pile points are required, which will increase the project cost. Currently, this type of problem remains a challenge for the industry. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a construction method using slag bricks, dry cement, and mud slurry for wall protection. This method can effectively solve complex foundation problems encountered during mud slurry wall cast-in-place pile construction, such as large areas of interbedded highly sensitive soil and liquefiable soil.

[0004] The present invention adopts the following technical solution:

[0005] A construction method using construction waste bricks, dry cement, and mud slurry for wall protection includes the following steps:

[0006] The first step is to fill the mud hole of the cast-in-place pile with construction waste bricks with a particle size ≤240mm up to the bottom of the hole, with a filling thickness of 2 to 3m;

[0007] The second step is to set up mixing and material extraction boreholes near the pile points; mix construction waste and dry cement in a 1:1 mass ratio in the boreholes, with the maximum particle size of the construction waste ≤120mm.

[0008] The third step involves using a double-bottomed cone drill bit to drill through the material intake hole and load the mixed filler material of construction waste and dry cement.

[0009] The fourth step is to close the valve and then quickly send the mixed filler to the collapsed part of the mud hole using the drill rod and the cone drill bit.

[0010] The fifth step is to use a conical drill bit to press the construction slag bricks that have been thrown into the bottom of the hole, and then rotate the conical drill bit in the opposite direction to press and expand the bricks into a soft plastic and fluid plastic layer to form the hole wall.

[0011] Step 6: After the cone drill bit touches the bottom, rotate it clockwise. After opening the valve, lift it 2 meters and continue rotating clockwise at a constant speed. Use gravity to discharge the slag and dry cement mixture in the drill bit.

[0012] Step 7: Rotate the rotary drill bit in the opposite direction and repeatedly raise and lower it at the collapsed part of the hole to evenly expand and fill the mixed filler to the hole wall;

[0013] Step 8: After standing for 72 hours, continue drilling. If the hole collapses again below, repeat the above steps.

[0014] The depth of the collapsed section of the mud hole in the cast-in-place pile is greater than 6m.

[0015] The diameter of the material extraction borehole is the same as that of the cast-in-place pile, and the depth does not exceed 3m. After the borehole is drilled, a protective casing is installed, and a layer of construction slag is laid at the bottom of the hole.

[0016] The amount of construction waste bricks dumped is calculated based on the extent of the collapse, and the maximum thickness does not exceed 3 meters.

[0017] The mixed filler cement is ordinary Portland cement with a grade of 42.5; the amount of material mixed each time is 3 / 4 of the volume of the material drilling hole.

[0018] The time for transporting the mixed filler through the cone drill bucket is controlled within 3 minutes.

[0019] When the rotary drilling bit rotates in the opposite direction to form a brick-concrete retaining wall, the lifting range of the rotary drilling bit is controlled within 3m.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. When the foundation contains a thick layer of fluid plastic or a large area of ​​interbedded and coexisting highly sensitive soil and liquefiable soil, the method of this invention is fast, simple and effective.

[0022] 2. It can save a lot of cement when dealing with large-area pile point collapse in mud-wall cast-in-place piles.

[0023] 3. The brick-concrete filling material in this invention can effectively improve the geological conditions of fluid and soft plastic layers. Attached Figure Description

[0024] Figure 1 Schematic diagram of filling the orifice with construction waste bricks;

[0025] Figure 2 A schematic diagram showing the transport of the mixture by the drill bit;

[0026] Figure 3 A schematic diagram illustrating how a drill bit uses gravity to expel the mixture.

[0027] Figure 4 A schematic diagram showing the brick-concrete-cement and mud-slurry wall formed after the drill barrel is repeatedly raised and lowered.

[0028] Among them: 1-filling the bored pile opening with construction waste bricks; 2-cone drill bucket; 2.1-drill bucket valve; 3-mixed filler; 4-brick-concrete-cement-slurry wall protection. Detailed Implementation

[0029] The invention will be further described with reference to the accompanying drawings.

[0030] As shown in the figure, the construction steps for using slag bricks, dry cement, and mud slurry for wall protection are as follows:

[0031] 1. Set up material feeding hole

[0032] Before constructing the mud-wall cast-in-place piles, a rotary drilling rig can be used to drill a hole near the mud pit. The diameter of the hole should be the same as that of the engineering pile, and the depth should not exceed three meters. After drilling, a casing should be installed, and a layer of construction slag should be laid at the bottom of the hole.

[0033] 2. Proportioning of slag material for pile hole preparation

[0034] Ordinary silicate dry cement of grade 42.5 and construction slag with a particle size ≤120mm are used as filler materials. The construction slag and dry cement are mixed in a mass ratio of 1:1. During mixing, the amount of material mixed each time is 3 / 4 of the volume of the material hole.

[0035] 3. Determine the location of the collapsed hole

[0036] When the construction of mud-wall cast-in-place piles is slow and the amount of slag produced increases significantly, construction should be stopped immediately, the mud circulation pump should be shut down, and the location of the collapsed hole should be determined by referring to the fluid plastic layer scale in the geological survey data.

[0037] 4. Fill with construction waste bricks

[0038] In the mud hole of the cast-in-place pile, construction waste bricks with a particle size of ≤240mm are thrown into the hole to the bottom of the hole, with a thickness of 2 to 3 meters.

[0039] 5. Load the mixed filler material of construction waste and dry cement.

[0040] Raise the cone drill bit from the borehole, open the drill bit valve, rotate it clockwise in the feed hole, and load the mixed construction waste and dry cement filler into the drill barrel. Then reverse the direction and close the valve.

[0041] 6. Transporting mixed packing materials

[0042] Use the drill rod and cone drill bit to quickly deliver the filling material to the collapsed part of the mud hole within 3 minutes. When the drum touches the bottom, rotate it forward, open the valves on both sides of the drill bit, then lift the drill bit slightly and rotate it forward at a constant speed. Use gravity to pour the mixed filling material in the drill bit to the area around the drill bit.

[0043] 7. Formation of brick-concrete-cement and mud slurry wall protection

[0044] The drill barrel is repeatedly raised and lowered at the bottom and rotated in the opposite direction at a uniform speed for 20 minutes to evenly expand and fill the filling material to the hole wall. The raising and lowering range of the drill barrel should be controlled within 3 meters.

[0045] 7. Interval time

[0046] After the brick-concrete-cement and mud slurry walls have stabilized, the drill bit should be pulled out. Based on the characteristics of low underground temperature and cement dilution, drilling should only be resumed after at least 72 hours of solidification. During this period, drilling at adjacent pile points is strictly prohibited.

[0047] 8. Continuous construction

[0048] After the treated brick-concrete-cement and mud slurry wall protection has solidified, start the drilling rig to continue drilling. If the soft plastic or fluid plastic layer is thick and the hole collapses again at the bottom, the above steps can be repeated.

Claims

1. A construction method using construction waste bricks + dry cement and mud slurry for wall protection, characterized in that: Includes the following steps: The first step is to fill the mud holes of the cast-in-place piles with construction waste bricks with a particle size of ≤240mm to the collapsed area, with a filling thickness of 2-3m. The second step is to set up mixing and material extraction boreholes near the pile points; mix construction waste and dry cement in a 1:1 mass ratio in the boreholes, with the maximum particle size of the construction waste ≤120mm. The third step involves using a double-bottomed cone drill bit to drill through the mixing and material extraction hole to load and remove the construction waste and dry cement mixed filler. The fourth step is to close the valve and then use the drill rod and double-bottom cone drill bit to quickly send the mixed filler to the collapsed part of the mud hole. The fifth step involves using a double-bottom conical drill bit to press and fill the construction slag bricks at the bottom of the hole. Then, the double-bottom conical drill bit rotates in the opposite direction to press and expand the bricks into a soft plastic or fluid plastic layer to form the hole wall. Step 6: After the double-bottom cone drill bit touches the bottom, rotate it clockwise. After opening the valve, lift it 2 meters and continue rotating clockwise at a constant speed. Use gravity to discharge the slag and dry cement mixture in the drill bit. Step 7: Rotate the rotary drill bit in the opposite direction and repeatedly raise and lower it at the collapsed part of the hole to evenly expand and fill the mixed filler to the hole wall; Step 8: After standing for 72 hours, continue drilling. If the hole collapses again below, repeat the above steps.

2. The construction method of using construction waste bricks + dry cement and mud slurry for wall protection according to claim 1, characterized in that: The depth of the collapsed section of the mud hole in the cast-in-place pile is greater than 6m.

3. The construction method of using construction waste bricks + dry cement and mud slurry for wall protection according to claim 1, characterized in that: The diameter of the mixing and material extraction borehole is the same as that of the cast-in-place pile, and the depth does not exceed 3m. After the borehole is drilled, a protective casing is installed, and a layer of construction slag is laid at the bottom of the hole.

4. The construction method of using construction waste bricks + dry cement and mud slurry for wall protection according to claim 1, characterized in that: The amount of construction waste bricks dumped is calculated based on the extent of the collapse, and the maximum thickness does not exceed 3 meters.

5. The construction method of using construction waste bricks + dry cement and mud slurry for wall protection according to claim 1, characterized in that: The mixed filler cement is ordinary Portland cement with a grade of 42.5; the amount of material mixed each time is 3 / 4 of the volume of the material extraction borehole.

6. The construction method of using construction waste bricks + dry cement and mud slurry for wall protection according to claim 1, characterized in that: The time for transporting the mixed filler in the double-bottom cone drill bucket is controlled within 3 minutes.

7. The construction method of using construction waste bricks + dry cement and mud slurry for wall protection according to claim 1, characterized in that: When the rotary drilling bit rotates in the opposite direction to form a brick-concrete retaining wall, the lifting range of the rotary drilling bit is controlled within 3m.

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