A method for fine-tuning the angle of corner pile anchor rods to avoid existing pile foundations in anchoring areas

Abstract

The present invention is a method for fine-tuning the angle of corner pile anchor rods that avoids existing pile foundations in an anchoring area, and the steps are as follows: tying a manufactured anchor rod angle adjustment box into a steel cage; adjusting the steel cage of the supporting pile steadily according to the design position of the supporting pile and the design position of the existing cast-in-place pile foundation in the anchoring area, ensuring that the center of the anchor rod angle adjustment box is aligned with the design anchoring area of ​​the positive corner anchor rod, and then pouring the supporting pile concrete; in the positive corner anchor rod hole forming operation, if the drill bit encounters an existing cast-in-place pile foundation, immediately withdraw the drilling machine, and use low-strength cement mortar to refill the formed anchor hole, fine-tune the drill bit position in the anchor rod angle adjustment box, and re-drill the hole. After the hole is formed, the positive corner anchor rod body is placed into the anchor hole, and pressure grouting is performed to form the positive corner anchor rod. The present invention can use the anchor rod angle adjustment box to fine-tune the positive corner anchor rod hole forming angle, avoid damage to the supporting pile when the pile body is re-drilled, and also avoid the decrease of the retaining bearing capacity of the supporting pile, and the operation is simple and the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit support, and in particular to a method for fine-tuning the driving angle of an angle pile anchor rod for avoiding an existing pile foundation in an anchoring area. Background Art

[0002] During the construction process, there are cases of phased construction, and there are also cases where the proposed building of the second phase is adjacent to the existing building of the first phase, and the pile foundation is set up under the existing building. The existing building has no basement, and the second phase building is designed to have a basement, and the basement floor is buried deeper than the existing floor of the first phase. In this case, the soil under the existing building floor needs to be protected before the foundation pit is excavated. When the pile anchor support system is used for protection, the positive corners below the existing building floor need to be protected by anchor rods. When setting the anchor holes, it is necessary to avoid the existing pile foundation, but the pile position can only be determined based on the drawings of the existing building. The positioning deviation of the pile foundation construction, the shrinkage of the pile hole, the expansion of the diameter, and even the positioning of the support piles may cause the drilling of the positive corners to conflict with the existing pile foundation. At this time, it is necessary to adjust the orientation of the anchor hole in the horizontal plane within a certain range, and it is necessary to withdraw the drill rod and adjust the angle appropriately before re-drilling the hole. For cast-in-place piles with one anchor at the outside corner, casing is often embedded at the position where the anchor rod is arranged on the pile body to facilitate the passage of the drill bit. It is very difficult to adjust the drilling angle on conventional cast-in-place piles with embedded casing. Summary of the invention

[0003] The present invention aims to solve the deficiencies of the prior art and provides a method for fine-tuning the driving angle of an angle pile anchor rod that avoids an existing pile foundation in an anchoring area.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for fine-tuning the angle of corner pile anchor rods to avoid existing pile foundations in anchoring areas, the specific steps are as follows:

[0006] S1. Production of anchor rod angle adjustment box:

[0007] The anchor angle adjustment box is prefabricated in the factory or welded on site;

[0008] The anchor rod angle adjustment box includes two horizontal plates arranged in parallel up and down, side plates are symmetrically arranged on the left and right sides between the two horizontal plates, and an adjustment channel is formed between the horizontal plates and the side plates. The width of the middle position of the horizontal plates is the smallest, and from the smallest width in the middle to the front and rear sides, it is an eight-shaped structure, and the front end face and the rear end face of the horizontal plate are both arc structures;

[0009] S2. Installation of anchor rod angle adjustment box:

[0010] When tying the steel cage of the support pile at the positive corner below the existing building floor, the longitudinal reinforcement of the support pile that conflicts with the anchor angle adjustment box is partially adjusted, and the originally evenly distributed longitudinal reinforcement of the support pile is arranged on both sides of the anchor angle adjustment box to form support pile reinforcement. According to the foundation pit support design drawing, the opening of the anchor angle adjustment box is aligned with the anchoring direction of the anchor rod at the positive corner, and the anchor angle adjustment box is fixed with the support pile reinforcement by welding or steel bar tying. Foam or sponge is filled inside the anchor angle adjustment box to avoid concrete being poured into the anchor angle adjustment box when pouring the support pile concrete, which affects the later use;

[0011] S3. Construction of support piles and crown beams:

[0012] Place the steel cage and anchor angle adjustment box into the pile hole of the supporting pile, pour concrete according to the design requirements, and cure until the strength meets the design requirements, and complete the construction of the supporting pile at the positive corner below the existing building floor; complete the construction of the cap beam on the top of the supporting pile, and cure until the concrete meets the design requirements, and the supporting pile and the cap beam form a whole;

[0013] S4. Direction adjustment of anchor rods at the outer corners:

[0014] Dig to a position 0.5m below the elevation of the anchor rod at the positive corner, remove the foam or sponge in the anchor rod angle adjustment box, and use the anchor drill to drill holes in the designed direction. When the drill bit encounters the existing cast-in-place pile foundation, immediately withdraw the drill and refill the existing anchor hole with low-strength quick-setting grouting material. Adjust the direction of the drill rod in the adjustment channel of the anchor rod angle adjustment box and drill in a direction away from the existing cast-in-place pile foundation. After the drill drill has drilled a hole, withdraw it, put the rod body of the positive corner anchor rod in the drill hole, and pressure-fill the anchor mortar.

[0015] S5. Protection of anchor rods at external corners:

[0016] A PVC anchor rod protection tube is installed at the end of the positive corner anchor rod within the range of the supporting pile body to prevent the positive corner anchor rod from being worn by the narrow part in the middle of the anchor rod angle adjustment box, and the gap between the PVC anchor rod protection tube and the anchor rod angle adjustment box is filled with sealing mortar to prevent the PVC anchor rod protection tube from swinging left and right;

[0017] S6. Tensioning construction of anchor rods at the outer corners:

[0018] The strength of the anchor body and the sealing mortar are maintained to meet the design requirements, the corner tension anchor rods and steel waist beams are installed, the rod bodies of the anchor rods at the external corners are tensioned and anchored, and the anchoring construction of the external corners below the floor of the existing building is completed.

[0019] In step S1, the minimum width of the middle position of the horizontal plate of the anchor rod angle adjustment box is 150 mm.

[0020] In step S1, the inclination angle of the hypotenuse of the figure eight structure at the front and rear ends of the horizontal plate is 15°.

[0021] In step S2, the anchor rod angle adjustment box is installed to maintain a horizontal state.

[0022] In step S4, the low-strength quick-setting grouting material used for anchor hole reinjection is a double-liquid grout of cement and water glass.

[0023] In step S4, after adjusting the direction of the drill rod in the adjustment channel of the anchor rod angle adjustment box, before the drill bit drills again, in order to ensure the stability of the drilling direction, a wedge block is temporarily placed against the side wall in the opening of the anchor rod angle adjustment box facing the foundation pit side to guide the drill rod.

[0024] In step S4, before pressure pouring the anchor mortar, a baffle is installed at the decomposition position of the free section and the anchor section of the anchor rod at the outer corner to avoid over-pouring of mortar in the free section due to poor control of the grouting amount.

[0025] The beneficial effects of the present invention are as follows: in the construction operation where the anchor hole drilling at the outer corner needs to avoid the existing bored pile foundation, the anchor angle adjustment box can be used to fine-tune the anchor hole drilling angle at the outer corner, thereby avoiding damage to the supporting piles when the pile body is re-drilled, and also avoiding a decrease in the retaining bearing capacity of the supporting piles. The operation is simple and the cost is low, and the drilling angle can be adjusted quickly, thereby avoiding delays in the construction of the retaining structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the anchor rod angle adjustment box in the present invention;

[0027] Figure 2 It is a schematic diagram of the anchor rod angle adjustment box in the present invention being installed on the steel cage;

[0028] Figure 3 It is a schematic diagram after the construction of the external corner anchor rod in the present invention is completed;

[0029] Figure 4 This is a front view of a PVC anchor rod protection tube arranged in the anchor rod angle adjustment box of the present invention;

[0030] Figure 5 It is a side view of a PVC anchor rod protection tube arranged in the anchor rod angle adjustment box of the present invention;

[0031] In the figure: 1-existing cast-in-place pile foundation; 2-support pile; 3-crown beam; 4-steel waist beam; 5-corner tension anchor rod; 6-external corner anchor rod; 7-support pile reinforcement; 8-support pile longitudinal reinforcement; 9-anchor rod angle adjustment box; 10-PVC anchor rod protection tube; 11-rebar cage; 12-existing building bottom plate below the external corner part;

[0032] 91- horizontal plate; 92- side plate; 93- adjustment channel;

[0033] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. The present invention is described in more detail by way of example with reference to the accompanying drawings in the following paragraphs. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0035] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0037] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0038] A method for fine-tuning the angle of corner pile anchor rods to avoid existing pile foundations in anchoring areas, the specific steps are as follows:

[0039] S1. Production of anchor rod angle adjustment box 9:

[0040] The anchor rod angle adjustment box 9 is prefabricated in the factory or welded on site;

[0041] The anchor rod angle adjustment box 9 can be made of steel plate, and can be integrally formed or welded;

[0042] Anchor rod angle adjustment box 9 Figure 1As shown, it includes two horizontal plates 91 arranged in parallel up and down, side plates 92 are symmetrically arranged on the left and right sides between the two horizontal plates 91, and an adjustment channel 93 is formed between the horizontal plate 91 and the side plates 92. The width of the horizontal plate 91 is the smallest at the middle position and it is in an eight-shaped structure from the smallest width in the middle to the front side and the rear side. The front end surface and the rear end surface of the horizontal plate 91 are both arc structures;

[0043] The minimum width of the middle position of the horizontal plate 91 of the anchor rod angle adjustment box 9 is 150 mm;

[0044] The inclined angle of the hypotenuse of the figure eight structure at the front and rear ends of the horizontal plate 91 is 15°;

[0045] Since the front and rear ends of the anchor rod angle adjustment box 9 are in a flared structure, the angle of the anchor rod 6 at the outer corner can be adjusted to a certain extent;

[0046] S2. Installation of anchor rod angle adjustment box 9:

[0047] The installation position of the anchor angle adjustment box 9 is determined according to the design elevation of the external corner anchor 6 and the length of the support pile 2;

[0048] When tying the steel cage 11 of the support pile 2 at the positive corner part 12 below the existing building floor, the support pile longitudinal reinforcement 8 that conflicts with the anchor rod angle adjustment box 9 is partially adjusted, and the originally evenly distributed support pile longitudinal reinforcement 8 is arranged on both sides of the anchor rod angle adjustment box 9 to form support pile reinforcement 7. Figure 2 As shown, according to the foundation pit support design drawing, the opening of the anchor rod angle adjustment box 9 is approximately aligned with the anchoring direction of the anchor rod 6 at the outer corner, and the anchor rod angle adjustment box 9 is fixed together with the support pile and reinforcement 7 by welding or steel bar binding, and foam or sponge is filled inside the anchor rod angle adjustment box 9 to prevent concrete from being poured into the anchor rod angle adjustment box 9 when pouring the support pile concrete, which affects the later use;

[0049] When installing the anchor rod angle adjustment box 9, it is necessary to connect the anchor rod angle adjustment box 9 with the steel cage 11 of the supporting pile 2 according to the buried depth of the anchor rod 6 at the positive corner. Since the two openings of the anchor rod angle adjustment box 9 are in a trumpet structure, which occupies the normal arrangement of the supporting pile longitudinal reinforcement 8, it is necessary to make local adjustments to the supporting pile longitudinal reinforcement 8, and arrange the supporting pile longitudinal reinforcement 8 affected by the opening of the anchor rod angle adjustment box 9 outside the anchor rod angle adjustment box 9, that is, Figure 2 The supporting piles and reinforcement 7;

[0050] The anchor rod angle adjustment box 9 is installed to maintain a horizontal state. When the support pile 2 is constructed to meet the verticality requirement, the anchor rod angle adjustment box 9 can be placed horizontally.

[0051] Construction of S3, support pile 2, and crown beam 3:

[0052] Put the steel cage 11 and the anchor angle adjustment box 9 into the pile hole of the supporting pile 2, and adjust the steel cage 11 of the supporting pile 2 smoothly according to the design position of the supporting pile 2 and the design position of the existing cast-in-place pile foundation 1 in the anchoring area, ensure that the center of the anchor angle adjustment box 9 is aligned with the designed anchoring area of ​​the anchor 6 at the positive corner, pour concrete according to the design requirements, and maintain until the strength meets the design requirements, and complete the construction of the supporting pile 2 at 12 positive corners below the existing building floor; complete the construction of the crown beam 3 on the top of the supporting pile 2, and maintain until the concrete meets the design requirements, and the supporting pile 2 and the crown beam 3 form a whole, such as Figure 3 As shown;

[0053] S4. Adjustment of the anchor rod 6 at the outer corner:

[0054] Dig to a position 0.5m below the elevation of the positive corner anchor 6, remove the foam or sponge in the anchor angle adjustment box 9, and use the anchor drill to drill holes in the designed direction. When the drill bit encounters the existing cast-in-place pile foundation 1, immediately withdraw the drill and refill the formed anchor hole with low-strength quick-setting grouting material, slightly adjust the direction of the drill rod in the adjustment channel 93 of the anchor angle adjustment box 9, and drill in a direction away from the existing cast-in-place pile foundation 1. After the drill drill has drilled a hole, withdraw it, put the rod body of the positive corner anchor 6 into the drill hole, and pressure-fill the anchor mortar;

[0055] The already formed boreholes need to be refilled with cement, water glass double liquid grout and other fast-setting low-strength grouting materials. The holes can only be re-drilled after the strength is increased. The purpose is to minimize the impact of abandoned boreholes on the drilling direction of the drill bit and avoid large drilling deviations in new boreholes.

[0056] After adjusting the direction of the drill rod in the adjustment channel 93 of the anchor rod angle adjustment box 9, before the drill bit drills again, in order to ensure the stability of the drilling direction, a wedge block is temporarily placed against the side wall in the opening of the anchor rod angle adjustment box 9 facing the foundation pit side to achieve the guiding effect on the drill rod;

[0057] After the hole is formed, the anchor rod 6 of the outer corner is placed and grouting is performed. Before the anchor mortar is pressed, a small baffle is installed at the decomposition position of the free section and the anchor section of the anchor rod 6 of the outer corner to avoid over-grouting of mortar in the free section due to poor control of the grouting amount.

[0058] S5. Protection of the external corner anchor 6:

[0059] A PVC anchor rod protection tube 10 is sleeved on the end of the positive corner anchor rod 6 within the range of the supporting pile 2 to prevent the positive corner anchor rod 6 from being worn by the narrow part in the middle of the anchor rod angle adjustment box 9, and the gap between the PVC anchor rod protection tube 10 and the anchor rod angle adjustment box 9 is filled tightly with sealing mortar to prevent the PVC anchor rod protection tube 10 from swinging left and right. Figure 4 , Figure 5 As shown;

[0060] Specifically, after pouring the mortar, the PVC anchor rod protection tube 10 needs to be immediately put on the rod body of the anchor rod 6 at the outer corner, and the gap between the opening of the anchor rod angle adjustment box 9 facing the inner side of the foundation pit and the PVC anchor rod protection tube 10 is sealed with cement mortar. After the anchor body and the sealing mortar are cured to the design strength, the steel waist beam 4 in the pit and the anchor pulling work of the anchor rod 6 at the outer corner can be carried out;

[0061] S6. Tensioning construction of anchor rod 6 at the outer corner:

[0062] After the strength of the anchor body and the sealing mortar meet the design requirements, the corner tension anchor rods 5 and the steel waist beam 4 are installed. The corner tension anchor rods 5 and the positive corner anchor rods 6 are installed at a certain distance apart from top to bottom. The rod body of the positive corner anchor rod 6 is tensioned and anchored to complete the anchoring construction of the positive corner part 12 below the existing building floor.

[0063] According to the present invention, in the construction operation where the hole drilling of the anchor rod 6 at the outer corner needs to avoid the existing bored pile foundation 1, the anchor rod angle adjustment box 9 can be used to fine-tune the hole drilling angle of the anchor rod 6 at the outer corner, so as to avoid damage to the supporting pile 2 when the pile body is re-drilled, and also avoid the reduction of the retaining bearing capacity of the supporting pile 2. The operation is simple and the cost is low, and the adjustment of the drilling angle can be realized relatively quickly, thus avoiding delays in the construction of the retaining structure.

[0064] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for fine-tuning the angle of corner pile anchor rods to avoid existing pile foundations in the anchoring area, characterized in that: The specific steps are: S1. Production of anchor rod angle adjustment box (9): The anchor rod angle adjustment box (9) is prefabricated in a factory or welded on site; The anchor rod angle adjustment box (9) comprises two horizontal plates (91) arranged in parallel up and down, side plates (92) are symmetrically arranged on the left and right sides between the two horizontal plates (91), and an adjustment channel (93) is formed between the horizontal plates (91) and the side plates (92). The width of the horizontal plates (91) is the smallest at the middle position and the horizontal plates (91) are in an eight-shaped structure from the middle position with the smallest width to the front side and the rear side. The front end face and the rear end face of the horizontal plates (91) are both arc-shaped structures. The minimum width of the horizontal plates (91) at the middle position of the anchor rod angle adjustment box (9) is 150 mm. S2. Installation of anchor rod angle adjustment box (9): When tying the steel cage (11) of the support pile (2) at the positive corner portion (12) below the existing building floor, the support pile longitudinal reinforcement (8) that conflicts with the anchor rod angle adjustment box (9) is partially adjusted, and the originally evenly distributed support pile longitudinal reinforcement (8) is arranged on both sides of the anchor rod angle adjustment box (9) to form support pile parallel reinforcement (7). According to the foundation pit support design drawing, the opening of the anchor rod angle adjustment box (9) is aligned with the anchoring direction of the positive corner anchor rod (6), and the anchor rod angle adjustment box (9) and the support pile parallel reinforcement (7) are fixed together by welding or steel bar tying, and foam or sponge is filled inside the anchor rod angle adjustment box (9) to prevent concrete from being poured into the anchor rod angle adjustment box (9) when pouring the support pile concrete, which affects the later use; S3. Construction of support piles (2) and crown beams (3): Place the steel cage (11) and the anchor angle adjustment box (9) into the pile hole of the support pile (2), pour concrete according to the design requirements, and cure until the strength reaches the design requirements, completing the construction of the support pile (2) at the positive corner part (12) below the existing building floor; complete the construction of the cap beam (3) on the top of the support pile (2), and cure until the concrete reaches the design requirements, and the support pile (2) and the cap beam (3) form a whole; S4. Adjustment of the external corner anchor rod (6): Dig to a position 0.5 m below the elevation of the positive corner anchor rod (6), remove the foam or sponge in the anchor rod angle adjustment box (9), and use the anchor drilling machine to drill a hole in the designed direction. When the drill bit encounters the existing cast-in-place pile foundation (1), immediately withdraw the drilling machine and refill the formed anchor hole with low-strength quick-setting grouting material. Adjust the direction of the drill rod in the adjustment channel (93) of the anchor rod angle adjustment box (9) and drill in a direction away from the existing cast-in-place pile foundation (1). After the drilling machine has drilled the hole, withdraw the rod body of the positive corner anchor rod (6) and place it in the drill hole, and pressure-fill the anchor mortar. S5. Protection of the external corner anchor rod (6): A PVC anchor rod protection tube (10) is sleeved on the end of the positive corner anchor rod (6) within the range of the pile body of the support pile (2) to prevent the positive corner anchor rod (6) from being worn by the narrow middle portion of the anchor rod angle adjustment box (9), and a gap between the PVC anchor rod protection tube (10) and the anchor rod angle adjustment box (9) is filled tightly with a sealing mortar to prevent the PVC anchor rod protection tube (10) from swinging left and right; S6. Tensioning construction of the external corner anchor rod (6): After the anchor body strength and the sealing mortar have reached the design requirements, the corner tension anchor rods (5) and the steel waist beam (4) are installed, and the rod body of the external corner anchor rod (6) is tensioned and anchored, thereby completing the anchoring construction of the external corner portion (12) below the existing building floor.

2. A method for fine-tuning the angle of corner pile anchor rods for avoiding existing pile foundations in the anchoring area according to claim 1, characterized in that: In step S1, the inclination angle of the hypotenuse of the figure eight structure at the front and rear ends of the horizontal plate (91) is 15°.

3. A method for fine-tuning the angle of corner pile anchor rods for avoiding existing pile foundations in the anchoring area according to claim 2, characterized in that: In step S2, the anchor rod angle adjustment box (9) is installed to maintain a horizontal state.

4. A method for fine-tuning the angle of corner pile anchor rods for avoiding existing pile foundations in the anchoring area according to claim 3, characterized in that: In step S4, the low-strength quick-setting grouting material used for anchor hole reinjection is a double-liquid grout of cement and water glass.

5. A method for fine-tuning the angle of corner pile anchor rods for avoiding existing pile foundations in the anchoring area according to claim 4, characterized in that: In step S4, after adjusting the direction of the drill rod in the adjustment channel (93) of the anchor rod angle adjustment box (9), before the drill bit re-enters the drilling, in order to ensure the stability of the drilling direction, a wedge block is temporarily placed close to the side wall of the opening of the anchor rod angle adjustment box (9) facing the foundation pit, thereby achieving a guiding effect on the drill rod.

6. A method for fine-tuning the angle of corner pile anchor rods for avoiding existing pile foundations in the anchoring area according to claim 5, characterized in that: In step S4, before pressure pouring the anchor mortar, a baffle is installed at the separation position of the free section and the anchor section of the external corner anchor rod (6) to avoid over-pouring of mortar in the free section due to poor control of the grouting amount.

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