A construction method for sector piles

Abstract

The present invention discloses a construction method for a fan-shaped pile, which comprises the following steps: Step 1, drilling a pilot hole; Step 2, inserting a barrier sheet: splicing a barrier sheet and an auxiliary sheet with the same semi-circular cross-section into a circular pipe, adjusting the orientation and then inserting it into the pile tip, pressing it into the pilot hole by guiding through the pile tip, and then pulling out the auxiliary sheet, leaving the barrier sheet in the pilot hole; Step 3, lowering a rotary spray head: connecting a rotary spray head with a main spray orifice to a grouting pipe, and controlling the rotary spray head to gradually sink to the bottom of the pilot hole by a drilling rig; Step 4, swing spraying construction: inputting a jet medium into the grouting pipe, spraying the jet medium into the soil through the main spray orifice of the rotary spray head, driving the rotary spray head to gradually rise by the drilling rig, and at the same time, the rotary spray head swings repeatedly left and right around the center line of the grouting pipe to complete the swing spraying construction; Step 5, forming a pile. The present invention realizes the construction of a fan-shaped pile by improving the rotary spray head and setting a barrier sheet, and has the advantages of convenient construction and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering, and particularly relates to a construction method for sector-shaped piles. Background Art

[0002] When reinforcing the foundation of an existing building, usually only the soil under the foundation is reinforced. Currently, the high-pressure jet grouting technology has been widely applied. The high-pressure jet grouting technology is to insert a grouting pipe with a jet nozzle into the designed soil layer depth, and then eject the jet medium in the form of a high-pressure jet from the jet nozzle to impact and cut the soil. In this way, grouting is continuously ejected from the bottom upwards. After the mixed grout solidifies, a consolidated body with a certain strength is formed in the soil layer. Among them, according to the different jet media, it can be divided into the single-pipe method, the double-pipe method, and the triple-pipe method. The single-pipe method: a single-layer jet pipe, only injecting cement slurry. The double-pipe method: also known as the slurry-gas jet method, is to simultaneously eject two media, high-pressure cement slurry and air, from a double grouting pipe in a horizontal jet to impact and break the soil. The triple-pipe method: is a slurry, water, and gas jet method, using a triple grouting pipe that separately conveys three media of water, gas, and slurry.

[0003] When using the above high-pressure jet grouting technology for reinforcement, since the equipment cannot be close to the foundation edge, the center of the jet grouting pile can only be designed outside the foundation contour line. Thus, whether it is a circular cross-section pile formed by the jet grouting method or a double-sector cross-section pile formed by the swing jet method, only about 1 / 3 of the jet grouting pile can extend under the foundation. When the foundation width is large, the jet grouting pile cannot reach the other side of the foundation, and it is necessary to construct another row of jet grouting piles on the other side of the foundation. In this way, it will inevitably cause waste of the high-pressure jet grouting pile, and the engineering cost of the reinforcement treatment is high. Summary of the Invention

[0004] In order to solve the problems pointed out in the background art, the present invention proposes a construction method for sector-shaped piles. By improving the jet nozzle and setting barrier sheets, a single-side swing jet construction method is formed to realize the construction of sector-shaped piles, which is convenient for construction and has a low cost.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A construction method for sector-shaped piles, comprising the following steps:

[0007] Step 1: Drilling a pilot hole:

[0008] Mechanically drill the marked hole positions through a drill rig;

[0009] Step 2: Inserting a barrier sheet:

[0010] Splice barrier sheets and auxiliary sheets with the same semi-circular cross-section into a circular pipe. After adjusting the orientation, insert it into the pile tip, and press it into the pilot hole by guiding through the pile tip. Then pull out the auxiliary sheet and keep the barrier sheet in the pilot hole;

[0011] Step 3: Sinking the rotary nozzle:

[0012] Connect the rotary nozzle with the main nozzle to the grouting pipe, and the drill rig controls the rotary nozzle to gradually sink to the bottom of the pilot hole;

[0013] Step 4: Swing jet grouting construction:

[0014] Input the jet medium into the grouting pipe. The jet medium is sprayed into the soil through the main nozzle of the rotary nozzle. The drill rig drives the rotary nozzle to gradually rise. At the same time, the rotary nozzle swings back and forth around the center line of the grouting pipe to complete the swing jet grouting construction;

[0015] Step 5: Pile formation:

[0016] When the grouting position of the rotary nozzle reaches the top of the pilot hole, pull out the barrier sheet. Wait for the slurry to solidify, and the fan-shaped pile is formed.

[0017] Further, the auxiliary sheet described in Step 2 has the same structure as the barrier sheet, or a semi-circular pipe sheet with the same diameter as the barrier sheet is adopted.

[0018] Further, the jet medium described in Step 4 adopts any one of the single-pipe method, the double-pipe method or the triple-pipe method.

[0019] Further, the diameter of the pilot hole described in Step 1 is 75 - 250 mm.

[0020] Further, the barrier sheet retained in the pilot hole in Step 2 is located on the back side of the spraying direction of the main nozzle. The barrier sheet includes a matrix and multiple rows of round holes distributed on the outer wall of the matrix. A row of reinforcing ribs is arranged between adjacent two rows of the round holes.

[0021] Further, a branch nozzle is opened on one side of the rotary nozzle opposite to the main nozzle in Step 3. A roller is arranged on each side of the branch nozzle.

[0022] Further, the angle of the left and right repeated swing of the rotary nozzle around the center line of the grouting pipe described in Step 4 can be controlled within 120°.

[0023] Through the above technical solutions, the beneficial effects of the present invention are:

[0024] In the swing jet grouting construction of the present invention, the rotary nozzle swings back and forth around the center line of the grouting pipe. The roller moves on the inner wall of the barrier sheet, and the branch nozzle of the rotary nozzle shoots low-pressure water flow towards the inner wall of the barrier sheet to remove obstacles for the movement of the roller on the inner wall of the barrier sheet and reduce its movement resistance.

[0025] The outer wall of the barrier sheet closely adheres to the inner wall of the pilot hole during the swing of the rotary nozzle, protecting the soil on this side from being cut. At the same time, the soil on the wall of the pilot hole supports the barrier sheet to provide support for the correct position of the rotary nozzle.

[0026] In the present invention, reinforcing ribs and round holes are provided on the barrier sheet to allow moisture to enter and be retained, reducing the resistance during the process of pulling out the barrier sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic connection diagram of the grouting pipe and the rotary nozzle in the third step of the present invention.

[0028] Figure 2 It is a schematic diagram of the state of the rotary nozzle and the barrier sheet in the pilot hole in the fourth step of the present invention.

[0029] Figure 3 It is a top view of the barrier sheet in the present invention.

[0030] Figure 4 It is a side view of the barrier sheet in the present invention.

[0031] Figure 5 It is a schematic structural diagram of the first step of the present invention.

[0032] Figure 6 It is a schematic structural diagram of the second step of the present invention.

[0033] Figure 7 It is the present invention Figure 6 A sectional view taken along line A-A in the present invention.

[0034] Figure 8 It is a schematic structural diagram of the third step of the present invention.

[0035] Figure 9 It is a schematic structural diagram of the fourth step of the present invention.

[0036] Figure 10 It is a schematic structural diagram of the fifth step of the present invention.

[0037] Figure 11 It is the present invention Figure 10 A sectional view taken along line B-B in the present invention.

[0038] The reference numerals in the drawings are:

[0039] 1 is the barrier sheet, 101 is the matrix, 102 is the round hole, 103 is the reinforcing rib, 2 is the auxiliary sheet, 3 is the rotary nozzle, 4 is the grouting pipe, 5 is the main nozzle, 6 is the branch nozzle, and 7 is the roller. DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention will be further described below in conjunction with the drawings and specific embodiments:

[0041] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "left", "right", "upper", "lower", "horizontal", "vertical", etc. are based on the attached Figure 1The orientation or positional relationship shown is 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 operate in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0042] Embodiment 1

[0043] As Figures 1 to 11 shown, a construction method for fan-shaped piles includes the following steps:

[0044] Step 1: Drilling a pilot hole:

[0045] Please refer to Figure 5 again, and mechanically drill the marked hole position through a drilling rig;

[0046] Step 2: Inserting the barrier sheet 1:

[0047] Please refer to Figure 6 again, splice the barrier sheet 1 and the auxiliary sheet 2 with the same semi-circular cross-section into a circular tube, adjust the orientation and insert it into the pile tip, and press it into the pilot hole through the downward extension of the pile tip, then pull out the auxiliary sheet 2 and retain the barrier sheet 1 in the pilot hole;

[0048] Step 3: Lowering the rotary nozzle 3:

[0049] Please refer to Figure 1 and Figure 8 again, connect the rotary nozzle 3 with the main nozzle 5 to the grouting pipe 4, and the drilling rig controls the rotary nozzle 3 to gradually sink to the bottom of the pilot hole;

[0050] Step 4: Swing jet grouting construction:

[0051] Please refer to Figure 9 again, input the jet medium into the grouting pipe 4, the jet medium is ejected into the soil through the main nozzle 5 of the rotary nozzle 3, the drilling rig drives the rotary nozzle 3 to gradually rise, and at the same time the rotary nozzle 3 swings left and right repeatedly around the center line of the grouting pipe 4 to complete the swing jet grouting construction;

[0052] Step 5: Forming the pile:

[0053] Please refer to Figure 10 again, when the grouting station of the rotary nozzle 3 reaches the top of the pilot hole, pull out the barrier sheet 1, and wait for the slurry to solidify to form a fan-shaped pile.

[0054] Please refer to Figure 7 again, the structure of the auxiliary sheet 2 described in Step 2 is the same as that of the barrier sheet 1, or a semi-circular pipe sheet with the same diameter as the barrier sheet 1 is used.

[0055] In the present invention, the jet medium described in Step 4 adopts any one of the single-tube method, the double-tube method, or the triple-tube method.

[0056] In this embodiment, the diameter of the pilot hole described in step one is 75 - 250 mm.

[0057] Please refer to again Figure 3 、 Figure 4 and Figure 8 , in step two, the barrier sheet 1 retained in the pilot hole is located on the back side of the spraying direction of the main spray nozzle 5. The barrier sheet 1 includes a matrix 101 and multiple rows of round holes 102 distributed on the outer wall of the matrix 101. A row of reinforcing ribs 103 is arranged between two adjacent rows of the round holes 102.

[0058] Please refer to again Figure 2 , in step three, a branch spray nozzle 6 is provided on one side of the rotary spray head 3 opposite to the main spray nozzle 5. A roller 7 is arranged on each side of the branch spray nozzle 6.

[0059] In this embodiment, the angle at which the rotary spray head 3 swings back and forth around the center line of the grouting pipe 4 in step four can be controlled within 120°.

[0060] After drilling a pilot hole in the foundation, lower the barrier sheet 1 into the pilot hole, connect the grouting pipe 4 with the rotary spray head 3, and sink to the bottom of the pilot hole for swing spraying. During swing spraying, the rotary spray head 3 swings back and forth around the center line of the grouting pipe 4, and the roller 7 moves on the inner side wall of the barrier sheet 1. The branch spray nozzle 6 of the rotary spray head 3 shoots low-pressure water flow towards the inner side wall of the barrier sheet 1 to remove obstacles for the movement of the roller 7 on the inner side wall of the barrier sheet 1 and reduce its movement resistance.

[0061] Taking the single-pipe method as an example, the outer wall of the barrier sheet 1 closely adheres to the inner wall of the pilot hole during the swinging process of the rotary spray head 3, protecting the soil on that side from being cut. At the same time, the soil on the inner wall of the pilot hole supports the barrier sheet 1, providing support for the correct positioning of the rotary spray head 3. Meanwhile, the cement slurry is sprayed out from the main spray nozzle 5 of the rotary spray head 3, impacting the soil on the inner wall of the pilot hole. When the dynamic pressure of the spraying flow exceeds the soil strength, the soil on the hole wall exfoliates and mixes with the cement slurry. Then, gradually lift the rotary spray head 3 upward and swing it left and right at a certain speed to forcibly stir and mix the cement slurry with the exfoliated soil. After the mixed slurry solidifies, the fan-shaped pile construction of the present invention is formed.

[0062] It is worth mentioning that after the above-mentioned fan-shaped pile swing spraying is completed, a steel reinforcement cage is further inserted into the pile to form a reinforced fan-shaped jet grouting pile. The specific technical requirements and implementation methods can be seen in the patent document with the authorization announcement number CN 214940359 U, an old pile under-pile structure. When the steel reinforcement cage is lowered into the hole, it can be replaced with the currently mature post-inserted steel bar placement technology in the industry. Moreover, when the present invention lowers the steel reinforcement cage, the implementation of a single-sector cross-section pile is more convenient than that of a double-sector cross-section pile. Therefore, it also provides a more flexible design option for the under-pile layout under the old pile in the above-mentioned patent document.

[0063] The above-described embodiments are only preferred embodiments of the present invention and do not limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structure, features, and principles described in the scope of the present invention patent shall be included within the scope of the patent application of the present invention.

Claims

1. A construction method for sector piles, characterized in that, It includes the following steps: Step 1, drilling a pilot hole: Mechanically drill the marked hole positions through a drilling rig; Step 2, inserting the barrier sheet (1): Splice the barrier sheet (1) and the auxiliary sheet (2) with the same semi-circular cross-section into a circular tube. After adjusting the orientation, insert it into the pile tip, and press it into the pilot hole by guiding it through the pile tip. Then pull out the auxiliary sheet (2) and keep the barrier sheet (1) in the pilot hole; Step 3, lowering the swing nozzle (3): Connect the swing nozzle (3) with the main nozzle (5) to the grouting pipe (4), and the drilling rig controls the swing nozzle (3) to gradually sink to the bottom of the pilot hole; Step 4, swing jet grouting construction: Input the jet medium into the grouting pipe (4). The jet medium is sprayed into the soil through the main nozzle (5) of the swing nozzle (3). The drilling rig drives the swing nozzle (3) to gradually rise, and at the same time, the swing nozzle (3) swings left and right repeatedly around the center line of the grouting pipe (4) to complete the swing jet grouting construction; Step 5, forming a pile: When the grouting position of the swing nozzle (3) reaches the top of the pilot hole, pull out the barrier sheet (1). Wait for the slurry to solidify, and a fan-shaped pile is formed.

2. The construction method of a sector pile according to claim 1, wherein The auxiliary sheet (2) described in Step 2 has the same structure as the barrier sheet (1), or a semi-circular pipe sheet with the same diameter as the barrier sheet (1) is used.

3. A method for constructing a sector pile according to claim 1, characterized in that The jet medium described in Step 4 adopts any one of the single pipe method, the double pipe method, or the triple pipe method.

4. A construction method of a sector pile according to claim 1, characterized in that, The diameter of the pilot hole described in Step 1 is 75 - 250 mm.

5. A method for constructing a sector pile according to claim 1, characterized in that, The barrier sheet (1) retained in the pilot hole in Step 2 is located on the back side of the spraying direction of the main nozzle (5). The barrier sheet (1) includes a matrix (101) and multiple rows of circular holes (102) distributed on the outer wall of the matrix (101). A row of reinforcing ribs (103) is arranged between adjacent two rows of the circular holes (102).

6. A method for constructing a sector pile according to claim 1, characterized in that, On the side of the swing nozzle (3) opposite to the main nozzle (5) in Step 3, a branch nozzle (6) is opened, and a roller (7) is arranged on each side of the branch nozzle (6).

7. A construction method for sector piles according to claim 1, characterized in that, The angle of the swing nozzle (3) swinging left and right repeatedly around the center line of the grouting pipe (4) in Step 4 is controlled within 120°.

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