A high-load bearing formed spiral anchor foundation and construction process

Abstract

The present invention discloses a high-load-bearing formed spiral anchor foundation and a construction process, which relates to the technical field of spiral anchor foundations. The invention comprises a hollow anchor rod and at least one spiral anchor plate and a plurality of grouting holes provided at the lower section of the anchor rod. A pressure plate structure is coaxially provided at the middle section of the anchor rod. The diameter of the pressure plate structure is substantially equal to the diameter of the spiral anchor plate. The pressure plate structure is used to compact the soil around the anchor rod as the anchor rod is screwed into the ground. In the process of the middle section of the anchor rod being screwed into the ground, the pressure plate structure compacts the soil around the anchor rod disturbed by the spiral anchor plate, thereby improving the pull-out bearing capacity. In the later stage of high-pressure grouting of the anchor rod, the cement slurry cannot rise from the high-density soil in the spiral anchor plate and around the anchor rod, but can only rise to the ground from the relatively low-density soil away from the anchor rod. Thus, the cement slurry is fully injected into the underground soil, the grouting range is wide, the grouting effect is good, and the bearing capacity, especially the horizontal bearing capacity, of the high-load-bearing formed spiral anchor foundation is significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of spiral anchor foundations, in particular to a high-load bearing formed spiral anchor foundation and a construction process. Background Art

[0002] With the long-distance construction of transmission lines, traditional large-scale excavation foundation construction takes a long time. Helical anchor foundations offer many advantages, such as shorter construction periods and superior environmental performance. However, due to the thinness of the anchor rods, the horizontal bearing capacity of helical anchor foundations is relatively low. Therefore, post-grouting helical anchor foundations and the more expensive group anchor helical anchor foundations are currently the most widely used.

[0003] Patent publication number CN215669471U discloses a grouting-type composite spiral anchor pile foundation, comprising an anchor rod and an anchor plate that rotates helically around the rod and is fixed to the sidewall of the rod. The system also includes a high-pressure grouting pipe disposed within the rod and extending to the outside of the rod, with a high-pressure grouting hole at the end. This system enhances the bearing capacity of the spiral anchor while reducing the variability of the bearing capacity of the spiral anchor foundation and reducing the amount of steel used.

[0004] Although traditional post-grouting spiral anchor foundations such as the above-mentioned patent can improve the vertical and horizontal bearing capacities of the foundation to a certain extent through high-pressure grouting technology, due to the disturbance of the soil by the anchor plate, the cement slurry will rise to the surface around the anchor rod during the high-pressure grouting process and cannot be fully injected into the underground soil, resulting in a small grouting range of the spiral anchor foundation and limited improvement in bearing capacity, especially the small improvement in horizontal bearing capacity. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-load-bearing formed spiral anchor foundation and construction process to solve the problem of traditional post-grouting spiral anchor foundation, in which the anchor plate disturbs the soil, and during the high-pressure grouting process, cement slurry rises up along the surface around the anchor rod and cannot be fully injected into the underground soil, resulting in insufficient grouting of the spiral anchor foundation and limited improvement in bearing capacity, especially a small increase in horizontal bearing capacity.

[0006] In order to achieve the above-mentioned objectives, the present invention provides the following technical solutions: a high-load-bearing formed spiral anchor foundation, comprising a hollow anchor rod and at least one spiral anchor plate and a plurality of grouting holes arranged in the lower section of the anchor rod, the middle section of the anchor rod being coaxially provided with a pressure plate structure, the diameter of the pressure plate structure being substantially equal to the diameter of the spiral anchor plate, and the pressure plate structure being used to compact the soil around the anchor rod during the process of the anchor rod being screwed into the ground.

[0007] Furthermore, the pressure plate structure includes a circular pressure plate arranged coaxially with the anchor rod.

[0008] Furthermore, the pressure plate structure also includes a stabilizing ring coaxially fixedly connected to the pressure plate, and a conical ring coaxial with the pressure plate and with a diameter decreasing from top to bottom is fixedly connected between the edge of the pressure plate and the middle of the stabilizing ring. The stabilizing ring and the conical ring are both located below the pressure plate.

[0009] Furthermore, the pressure plate structure and the anchor rod are welded or screwed.

[0010] Furthermore, the pressure plate structure and the anchor rod are movably connected along the axial direction to adjust the distance between the pressure plate structure and the top of the anchor rod.

[0011] Furthermore, the pressure plate structure is fitted with the anchor rod through a clearance between the sleeve and the anchor rod to achieve axial movement along the anchor rod. A first limiting bolt is radially threaded on the sleeve, and a plurality of first limiting holes arranged along the axial direction of the anchor rod are opened on the middle section of the anchor rod. The pressure plate structure is plugged into and fitted with any first limiting hole through the first limiting bolt to lock the pressure plate structure and the anchor rod.

[0012] Furthermore, the pressure plate structure is matched with the anchor rod through the clearance of the sleeve to achieve axial movement along the anchor rod, and a high-position adjusting rod is connected to one side of the anchor rod in an axial sliding manner. The bottom of the high-position adjusting rod is used to abut and cooperate with the sleeve, and a second limiting bolt is screwed on the top. The upper section of the anchor rod is provided with a plurality of second limiting holes arranged along the axial direction of the anchor rod, and the high-position adjusting rod is plugged and matched with any second limiting hole through the second limiting bolt to lock the high-position adjusting rod and the anchor rod.

[0013] Furthermore, a spiral guide groove is provided on the peripheral side surface of the middle section of the anchor rod, and the spiral direction of the guide groove is opposite to the spiral direction of the spiral anchor plate. A convex portion is provided on the inner wall of the sleeve, and the convex portion is located in the guide groove so that the pressure plate structure can move along the guide groove.

[0014] Furthermore, the pitch of the guide groove is 50-100 mm.

[0015] The present invention also provides a construction process, which is based on the above-mentioned high-load-bearing formed spiral anchor foundation and includes the following steps: S1, connecting the top of the anchor rod to a spiral anchor drilling rig, so that the middle and lower sections of the anchor rod are screwed into the soil, and the pressure plate structure compacts the soil around the anchor rod downward, forming a 650-750mm deep hole between the pressure plate structure and the ground, and the upper section of the anchor rod is exposed 300mm above the ground; S2, removing the spiral anchor drilling rig, pouring PO42.5 cement slurry into the hole, and subsequently curing for 24 hours; S3, connecting the top of the anchor rod to a grouting machine, injecting PO42.5 cement slurry into the inner cavity of the anchor rod, and pressing the PO42.5 cement slurry into the soil through the grouting hole for curing for 24 hours. The grouting rate is controlled at 18-30L / min, and the grouting pressure is maintained at 0.7-1.5MPa. The grouting termination condition is surface grouting; S4, removing the grouting machine, and the construction is completed after curing for 24 hours.

[0016] Compared with the prior art, the present invention provides a high-load-bearing formed spiral anchor foundation and construction process. Although the spiral anchor plate disturbs the soil around the anchor rod during the process of screwing the lower section of the anchor rod into the ground, the pressure plate structure compacts the soil around the anchor rod disturbed by the spiral anchor plate during the process of screwing the middle section of the anchor rod into the ground. The soil originally on the upper part of the pressure plate structure is pressed to the bottom of the pressure plate structure, thereby increasing the cohesion and internal friction angle, and thus improving the pull-out bearing capacity of the high-load-bearing formed spiral anchor foundation. The holes automatically formed above the pressure plate structure are used to pour cement slurry, and no additional holes need to be excavated. In the later stage of high-pressure grouting of the anchor rod, the cement slurry cannot rise from the high-density soil in the spiral anchor plate and around the anchor rod, and can only rise to the ground from the relatively low-density soil far away from the anchor rod, so that the cement slurry is fully injected into the underground soil, the grouting range is wide, the grouting effect is good, and the bearing capacity, especially the horizontal bearing capacity, of the high-load-bearing formed spiral anchor foundation is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly describe the embodiments of the present application or the technical solutions in the prior art, a brief introduction to the drawings required for use in the embodiments is given below.

[0018] Figure 1 A schematic diagram of the overall structure provided for Example 1;

[0019] Figure 2 A schematic structural diagram of the pressure plate structure provided in Example 1;

[0020] Figure 3 A schematic diagram of the overall structure provided for Example 2;

[0021] Figure 4 A cross-sectional view of the overall structure provided for Example 2;

[0022] Figure 5 This is a schematic diagram of the overall structure provided for Example 3;

[0023] Figure 6 A schematic diagram of the partial structure provided for Example 3;

[0024] Figure 7 This is a schematic diagram of the overall structure provided for Example 4;

[0025] Figure 8 This is a structural schematic diagram of the pressure plate structure provided in Example 4.

[0026] Description of reference numerals:

[0027] 1. Anchor rod; 101. Lower section; 102. Middle section; 103. Upper section; 2. Grouting hole; 3. Spiral anchor plate; 4. Flange plate; 5. Reinforcing rib; 6. Pressure plate structure; 601. Pressure plate; 602. Stabilizing ring; 603. Conical ring; 604. Sleeve; 7. First limiting bolt; 8. First limiting hole; 9. High-position adjusting rod; 10. Second limiting bolt; 11. Second limiting hole; 12. Guide groove; 13. Protrusion. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] Example 1

[0030] See also Figure 1-2 , an embodiment of the present invention provides a high-load-bearing formed spiral anchor foundation, including an anchor rod 1, the interior of the anchor rod 1 has a hollow inner cavity, the top of the anchor rod 1 is fixedly connected to a flange 4, a plurality of reinforcing ribs 5 are provided between the lower surface of the flange 4 and the peripheral side of the anchor rod 1, the lower section 101 of the anchor rod 1 is provided with at least 1-3 spiral anchor plates 3 and a plurality of grouting holes 2, each grouting hole 2 is connected to the inner cavity of the anchor rod 1, the middle section 102 of the anchor rod 1 is fixedly connected to a pressure plate structure 6 by welding or screwing, the pressure plate structure 6 is 950-1050mm away from the top of the anchor rod 1, is circular as a whole and is coaxially arranged with the anchor rod 1, the diameter of the pressure plate structure 6 is substantially equal to the diameter of the spiral anchor plate 3 (an error of ±2mm is allowed), and the pressure plate structure 6 is used to compact the soil around the anchor rod 1 during the process of the anchor rod 1 being screwed into the ground. The pressure plate structure 6 includes at least a circular pressure plate 601 coaxially arranged with the anchor rod 1. In order to make the pressure plate 601 press down the soil better and prevent the pressure plate 601 from deforming easily during the pressing process, in addition to improving the strength of the pressure plate 601 itself, a stabilizing ring 602 is coaxially fixedly connected to the pressure plate 601. A cone ring 603 is fixedly connected between the outer edge of the pressure plate 601 and the middle part of the stabilizing ring 602. The cone ring 603 is coaxial with the pressure plate 601 and the diameter of the cone ring 603 decreases from top to bottom. The stabilizing ring 602 and the cone ring 603 are both located below the pressure plate 601, and the stabilizing ring 602, the cone ring 603 and the pressure plate 601 are welded together.

[0031] In the high-load-bearing formed spiral anchor foundation in the above technical solution, although the spiral anchor plate 3 disturbs the soil around the anchor rod 1 during the process of screwing the lower section 101 of the anchor rod 1 into the ground, the pressure plate structure 6 compacts the soil around the anchor rod 1 disturbed by the spiral anchor plate 3 during the process of screwing the middle section 102 of the anchor rod 1 into the ground, and the soil originally on the upper part of the pressure plate structure 6 is pressed to the bottom of the pressure plate structure 6, thereby increasing the cohesion and internal friction angle, thereby improving the pull-out bearing capacity of the high-load-bearing formed spiral anchor foundation, and the hole formed above the pressure plate structure 6 is used to pour cement slurry, without the need for additional excavation of holes. In the later high-pressure grouting stage of the anchor rod 1, the cement slurry cannot rise from the high-density soil inside the spiral anchor plate 3 and around the anchor rod 1, and can only rise to the ground from the relatively low-density soil far away from the anchor rod 1, so that the cement slurry is fully injected into the underground soil, the grouting range is wide, the grouting effect is good, the bearing capacity of the high-load-bearing formed spiral anchor foundation is high, and especially the horizontal bearing capacity is significantly improved.

[0032] The design of the pressure plate structure 6 is that when the pressure plate 601 presses the soil downward, the stabilizing ring 602 penetrates into the soil below the pressure plate 601, and both the inner and outer sides of the stabilizing ring 602 are filled with compacted soil, thereby effectively reducing the degree of outward deformation of the pressure plate 601; the cone ring 603 is arranged on the outer side of the stabilizing ring 602, and is in a shape of wide at the top and narrow at the bottom. In the process of compacting the soil downward with the pressure plate 601, on the one hand, the soil below the pressure plate 601 originally all acts on the pressure plate 601 upward, and part of it is dispersed by the conical surface of the cone ring 603 into a horizontal inward force on the pressure plate 601 and the stabilizing ring 602, which can further reduce the degree of outward deformation of the pressure plate 601, and on the other hand When the soil is pressed down by the cone ring 603, part of the soil is compacted to the bottom of the cone ring 603, and the other part of the soil is guided to the outside of the cone ring 603 by the conical surface of the cone ring 603, so that the soil below the pressure plate 601 is compacted while the soil outside the pressure plate 601 is also compacted, that is, the density of the side wall of the hole above the pressure plate 601 is also improved, and the cone ring 603 squeezes part of the soil below the pressure plate 601 to the outside of the pressure plate 601, which can further increase the depth of the pressure plate 601 pressed into the soil without reducing the diameter of the pressure plate 601, thereby increasing the depth of the hole above the pressure plate 601 and the depth of cement poured in the subsequent hole, which can improve the bearing capacity of the high-load-bearing formed spiral anchor foundation.

[0033] Example 2

[0034] See Figure 3-4In order to improve the geological adaptability of the high-load-bearing formed spiral anchor foundation, the pressure plate structure 6 and the anchor rod 1 are designed to be movably connected. The inner ring of the pressure plate 601 of the pressure plate structure 6 is welded with a sleeve 604. The pressure plate 601 is clearance-matched with the anchor rod 1 through the sleeve 604, so that the pressure plate structure 6 can move along the axial direction of the anchor rod 1, thereby adjusting the distance between the pressure plate structure 6 and the top of the anchor rod 1.

[0035] A locking structure is also designed between the sleeve 604 and the anchor rod 1, which can lock the sleeve 604 to the anchor rod 1. Specifically, the locking structure adopts a structure in which a first limiting bolt 7 cooperates with multiple first limiting holes 8, that is, a first limiting bolt 7 is radially screwed on the sleeve 604, and multiple first limiting holes 8 are opened on the middle section 102 of the anchor rod 1. Each first limiting hole 8 is equidistantly arranged along the axial direction of the anchor rod 1. The pressure plate structure 6 can be plugged and matched with any first limiting hole 8 through the first limiting bolt 7. When the pressure plate structure 6 moves to the specified position along the anchor rod 1, the first limiting bolt 7 is rotated to be inserted into the currently corresponding first limiting hole 8, thereby locking the pressure plate structure 6 and the anchor rod 1.

[0036] In this embodiment, the distance between the pressure plate structure 6 and the top of the anchor rod 1 can be adjusted to account for the differences in the original soil density of different plots. For plots with high original soil density, the distance between the pressure plate structure 6 and the top of the anchor rod 1 is shortened. In this way, when the high-load-bearing formed spiral anchor foundation is screwed into the ground to a predetermined depth, the pressure plate structure 6 has a relatively small stroke to compact the soil below. This can not only make the soil below the pressure plate 601 more dense, but also reduce the load on the pressure plate 601 to avoid excessive deformation of the pressure plate 601 and reduce the load on the spiral anchor drilling rig. For plots with low original soil density, the distance between the pressure plate structure 6 and the top of the anchor rod 1 is lengthened. In this way, when the high-load-bearing formed spiral anchor foundation is screwed into the ground to a predetermined depth, the pressure plate structure 6 has a relatively large stroke to compact the soil below. This can also make the soil below the pressure plate 601 more dense, form a deeper hole above the pressure plate 601 for pouring cement, and enhance the overall bearing capacity of the high-load-bearing formed spiral anchor foundation.

[0037] Example 3

[0038] See Figure 5-6, the difference between this embodiment and the second embodiment lies in the specific structure of the locking structure. In this embodiment, the locking structure adopts a structure in which a high-position adjusting rod 9, a second limiting bolt 10 and a plurality of second limiting holes 11 cooperate with each other, that is, a high-position adjusting rod 9 is axially slidably connected to one side of the anchor rod 1, and a plurality of vertically arranged rings are provided on the side of the anchor rod 1. The high-position adjusting rod 9 is passed through each ring. The high-position adjusting rod 9 moves along the anchor rod 1 to change the distance between its bottom and the pressure plate structure 6. The bottom of the high-position adjusting rod 9 is used to abut and cooperate with the sleeve 604 to limit the pressure plate structure 6 moves upward along the anchor rod 1. A second limiting bolt 10 is screwed onto the top of the high-position adjustment rod 9. A plurality of second limiting holes 11 are formed in the upper section 103 of the anchor rod 1. Each second limiting hole 11 is equidistantly arranged along the axial direction of the anchor rod 1. The second limiting bolt 10 is screwed onto the top of the high-position adjustment rod 9. The high-position adjustment rod 9 can be plugged into any second limiting hole 11 through the second limiting bolt 10. When the high-position adjustment rod 9 is adjusted to a preset position, the second limiting bolt 10 is rotated to be inserted into the corresponding second limiting hole 11, thereby locking the high-position adjustment rod 9 to the anchor rod 1. The number of locking structures is preferably 3-6, equidistantly distributed around the anchor rod 1. Each locking structure needs to be adjusted synchronously during adjustment. During the process of the pressure plate structure 6 compacting the soil, the pressure plate structure 6 can be abutted and limited together, thereby effectively preventing the large reaction force of the pressure plate structure 6 from causing the single high-position adjustment rod 9 to bend and deform.

[0039] During the process of spinning the high-load-bearing formed spiral anchor foundation into the ground, when the pressure plate 601 has been pressed into the soil but the high-load-bearing formed spiral anchor foundation has not yet been in place, if the load of the spiral anchor drilling rig spinning the high-load-bearing formed spiral anchor foundation increases significantly or exceeds the set load, at this time, it is only necessary to pause the power output of the spiral anchor drilling rig, loosen the second limit bolt 10 and move the high-position adjusting rod 9 upward so that the bottom of the high-position adjusting rod 9 is upwardly separated from the pressure plate structure 6 by a certain distance, and then lock the high-position adjusting rod 9 and the anchor rod 1 by screwing the second limit bolt 10 into the currently corresponding second limit hole 11, and then continue to start the spiral anchor drilling rig to spin the high-load-bearing formed spiral anchor foundation downward. The pressure plate structure 6 moves upward relative to the anchor rod 1 during the descent of the anchor rod 1 until it abuts against the bottom of the high-position adjusting rod 9 again, and the high-load-bearing formed spiral anchor foundation can be smoothly spun into place.

[0040] The advantage of this embodiment is that it can adjust the high-position adjustment rod 9 from the upper section 103 of the anchor rod 1 exposed to the ground based on the resistance feedback after the pressure plate structure 6 is pressed into the soil, thereby achieving the purpose of adjusting the distance between the pressure plate structure 6 that has been pressed into the soil and the top of the anchor rod 1. There is no need to retract the anchor rod 1 upward until the pressure plate structure 6 returns to the ground before adjusting the position of the pressure plate structure 6 as in the second embodiment.

[0041] Example 4

[0042] See Figure 7-8 The difference between this embodiment and the third embodiment is that a spiral guide groove 12 is additionally provided on the circumferential side surface of the middle section 102 of the anchor rod 1. The spiral direction of the guide groove 12 is opposite to the spiral direction of the spiral anchor plate 3. The pitch of the guide groove 12 is 50-100 mm. A protrusion 13 is provided on the inner wall of the sleeve 604. The protrusion 13 is located in the guide groove 12 so that the pressure plate structure 6 can move along the guide groove 12. In this way, the distance between the pressure plate structure 6 and the top of the anchor rod 1 can be adjusted by simply moving the pressure plate structure 6 along the guide groove 12.

[0043] During the period when the high-load-bearing formed spiral anchor foundation in Example 3 is being rotated underground, the upward reaction force and the reaction force in the reverse rotation direction that the pressure plate structure 6 is subjected to when compacting the soil are both relatively large, especially when the soil is compacted more tightly under the pressure plate structure 6. This causes the high-position adjusting rod 9 to be subjected to very large vertical pressure and horizontal torsional force at the same time (the horizontal torsional force is generated by the friction between the pressure plate structure 6 and the compacted soil and the abutment friction between the bottom of the high-position adjusting rod 9 and the sleeve 604). As a result, the high-position adjusting rod 9 of the steel structure is still likely to bend and deform. On the one hand, the distance between the pressure plate structure 6 and the top of the anchor rod 1 is reduced. On the other hand, after the high-position adjusting rod 9 is bent, it is difficult for it to move along the anchor rod 1, so that the position of the high-position adjusting rod 9 and the pressure plate structure 6 cannot be adjusted.

[0044] This embodiment solves the problem faced in the third embodiment by adding a reverse spiral guide groove 12 and a protrusion 13 that cooperates with the guide groove 12 . The present embodiment ensures that the pressure plate structure 6 can be moved and adjusted along the anchor rod 1 through the high-position adjusting rod 9. In this embodiment, during the period when the post-grouting spiral anchor foundation is rotating underground, a part of the upward reaction force exerted on the pressure plate structure 6 when compacting the soil directly acts on the upper groove wall of the guide groove 12, that is, on the anchor rod 1, and only the remaining part of the upward reaction force acts on the high-position adjusting rod 9, thereby greatly reducing the vertical pressure exerted on the high-position adjusting rod 9. Almost all of the reaction force in the reverse direction exerted on the pressure plate structure 6 when compacting the soil is absorbed by the upper groove wall of the guide groove 12, that is, absorbed by the anchor rod 1, thereby fully alleviating the horizontal torsional force exerted by the pressure plate structure 6 on the high-position adjusting rod 9, making the high-position adjusting rod 9 of the same material and strength not easy to bend and deform, and the high-position adjusting rod 9 can always accurately limit the pressure plate structure 6, and the high-position adjusting rod 9 can move smoothly along the anchor rod 1 when the height of the pressure plate structure 6 needs to be adjusted. Therefore, in this embodiment, only 1-2 locking structures are required, the high-position adjusting rod 9 is not easily deformed, and a smaller number of locking structures also makes it convenient to screw the second limiting bolt 10 to adjust the high-position adjusting rod 6.

[0045] The present invention also provides a construction process for a high-load forming spiral anchor foundation, which mainly includes the following steps: first, the flange 4 on the top of the anchor rod 1 is screwed to the flange 4 at the power output end of the spiral anchor drilling rig, so that the middle section 102 and the lower section 101 of the anchor rod 1 are screwed into the soil, and the pressure plate structure 6 compacts the soil around the anchor rod 1 downward, forming a hole with a depth of 650-750mm (preferably 700mm) between the pressure plate structure 6 and the ground, and the upper section 103 of the anchor rod 1 is exposed 300mm above the ground, and the high-load forming spiral anchor foundation spinning stage is completed; then the spiral anchor drilling rig is dismantled and the PO42.5 cement slurry is poured into the hole and subsequently cured for 24 hours; then the flange 4 on the top of the anchor rod 1 is sealed and screwed with the flange 4 at the end of the grouting pipe of the grouting machine, and PO42.5 cement slurry is injected into the inner cavity of the anchor rod 1. The PO42.5 cement slurry is pressed into the soil through the grouting hole 2 and cured for 24 hours. The grouting rate is controlled at 18-30L / min, and the grouting pressure is maintained at 0.7-1.5MPa. The grouting termination condition is that the grouting emerges from the ground; finally, the grouting machine is dismantled, and after the grouting cement slurry is cured for 24 hours, the construction of the high-load-bearing formed spiral anchor foundation is completed.

[0046] The screw anchor drill provides rotational force and downward pressure for the anchor rod 1, employing existing technology. The grouting machine, used to inject pressurized cement slurry into the inner cavity of the anchor rod 1, also employs existing technology. The water-cement ratio (mass ratio of water to cement) of the PO42.5 cement slurry used in both applications ranges from 0.4 to 0.6, preferably 0.5. This construction process significantly improves the vertical and horizontal bearing capacity of the pressure-type, post-grouting screw anchor foundation. Moreover, since the pressure plate structure 6 will compact the soil beneath it and the soil on the side walls of the hole, grouting operations can be carried out while injecting PO42.5 cement slurry into the hole. The injected PO42.5 cement slurry will not bubble upward along the spiral anchor plate 3 and the anchor rod 1, so that the PO42.5 cement slurry in the hole and the PO42.5 cement slurry injected through the inner cavity of the anchor rod 1 can be simultaneously cured for 24 hours. There is no need to wait for the PO42.5 cement slurry in the hole to be cured for 24 hours before grouting operations, thereby shortening the construction period by half.

[0047] Furthermore, in single-pile vertical pullout static load tests, the ultimate pullout bearing capacity of the high-load-bearing formed spiral anchor foundation, when configured with a spiral anchor plate diameter ratio of 2.5, increased by 80.47% compared to traditional spiral anchor foundations. When configured with a spiral anchor plate diameter ratio of 3.5, the ultimate pullout bearing capacity of the high-load-bearing formed spiral anchor foundation increased by 67.13% compared to traditional spiral anchor foundations. In single-pile in-situ tests, the ultimate horizontal bearing capacity of the high-load-bearing formed spiral anchor foundation, with a 140mm anchor rod diameter and a 3.5 spiral anchor plate diameter ratio, increased by 219.06% compared to traditional spiral anchor foundations. The ultimate horizontal bearing capacity of the high-load-bearing formed spiral anchor foundation, with an anchor rod diameter of 140mm and a 3.5 spiral anchor plate diameter ratio, increased by 103.33% compared to traditional spiral anchor foundations.

[0048] The above description of certain exemplary embodiments of the present invention should not be construed as limiting the scope of protection of the claims of the present invention. For those skilled in the art, the described embodiments may be modified in other different ways without departing from the spirit and scope of the present invention.

Claims

1. A high-load bearing formed spiral anchor foundation, comprising a hollow anchor rod (1) and at least one spiral anchor plate (3) and a plurality of grouting holes (2) provided on the lower section (101) of the anchor rod (1), characterized in that: A pressure plate structure (6) is coaxially arranged on the middle section (102) of the anchor rod (1), wherein the diameter of the pressure plate structure (6) is substantially equal to the diameter of the spiral anchor plate (3), and the pressure plate structure (6) is used to compact the soil around the anchor rod (1) when the anchor rod (1) is screwed into the ground; The pressure plate structure (6) and the anchor rod (1) are movably connected along the axial direction to adjust the distance between the pressure plate structure (6) and the top of the anchor rod (1); The pressure plate structure (6) is clearance-matched with the anchor rod (1) through the sleeve (604) to achieve axial movement along the anchor rod (1); one side of the anchor rod (1) is axially slidably connected to a high-position adjustment rod (9); the bottom of the high-position adjustment rod (9) is used to abut against the sleeve (604); the top is screwed with a second limiting bolt (10); the upper section (103) of the anchor rod (1) is provided with a plurality of second limiting holes (11) arranged axially along the anchor rod (1); the high-position adjustment rod (9) is plugged into and matched with any second limiting hole (11) through the second limiting bolt (10) to lock the high-position adjustment rod (9) with the anchor rod (1).

2. The high-load bearing formed spiral anchor foundation according to claim 1, characterized in that: The pressure plate structure (6) comprises a circular pressure plate arranged coaxially with the anchor rod (1).

3. The high-load bearing formed spiral anchor foundation according to claim 2, characterized in that: The pressure plate structure (6) further comprises a stabilizing ring (602) coaxially fixedly connected to the pressure plate, a conical ring (603) coaxial with the pressure plate and with a diameter decreasing from top to bottom fixedly connected between the outer edge of the pressure plate and the middle of the stabilizing ring (602), and both the stabilizing ring (602) and the conical ring (603) are located below the pressure plate.

4. The high-load bearing formed spiral anchor foundation according to claim 1, characterized in that: A spiral guide groove (12) is provided on the peripheral side surface of the middle section (102) of the anchor rod (1), and the spiral direction of the guide groove (12) is opposite to the spiral direction of the spiral anchor plate (3). A convex portion (13) is provided on the inner wall of the sleeve (604), and the convex portion (13) is located in the guide groove (12) so that the pressure plate structure (6) can move along the guide groove (12).

5. The high-load bearing formed spiral anchor foundation according to claim 4, characterized in that: The pitch of the guide groove (12) is 50-100 mm.

6. A construction process, characterized in that: The high-load bearing formed spiral anchor foundation according to any one of claims 1 to 5 is implemented, comprising the following steps: S1. Connect the top of the anchor rod (1) to the screw anchor drill, screw the middle section (102) and the lower section (101) of the anchor rod (1) into the soil, and compact the soil around the anchor rod (1) downwards with the pressure plate structure (6). A hole with a depth of 650-750 mm is formed between the pressure plate structure (6) and the ground, and the upper section (103) of the anchor rod (1) is exposed 300 mm above the ground. S2. Remove the screw anchor drill, pour PO42.5 cement slurry into the hole, and then maintain for 24 hours; S3. Connect the top of the anchor rod (1) to the grouting machine and inject PO42.5 cement slurry into the inner cavity of the anchor rod (1). The PO42.5 cement slurry is pressed into the soil through the grouting hole (2) and cured for 24 hours. The grouting rate is controlled at 18-30L / min and the grouting pressure is maintained at 0.7-1.5MPa. The grouting termination condition is the emergence of grouting on the ground. S4. Remove the grouting machine and the construction will be completed after 24 hours of curing.

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