Composite grouting screw anchor foundation

Abstract

The invention discloses a composite grouting spiral anchor foundation which comprises a hollow anchor rod, an anchor disc arranged outside the anchor rod, an outer cylinder arranged on the periphery of the anchor rod in a sleeving mode and a grouting cylinder coaxially arranged in an inner cavity of the anchor rod, a composite cavity is formed between the outer cylinder and the anchor rod, and guniting holes are formed in the outer cylinder. An annular groove is formed in the anchor rod and correspondingly communicates with a slurry outlet of the grouting barrel, and a positioning assembly used for limiting the relative position of the grouting barrel and the anchor rod is arranged in the grouting barrel. The relative positions of the grouting barrel and the anchor rod are limited through the positioning assembly, so that grouting is conducted after the grout outlet and the annular groove are stably communicated; slurry enters the composite cavity through the slurry outlet and the annular groove, is subjected to confluence buffering and pressure homogenization in the composite cavity and then is discharged outwards in the circumferential direction through the slurry spraying holes of the outer cylinder, so that slurry is discharged from the slurry spraying holes more uniformly, and the grouting controllability and the bearing stability are improved; the positioning assembly ensures that the communication state is kept consistent under lowering, screwing-in and pressure disturbance, and the reliability of the grouting channel is improved.

Description

Technical Field

[0001] This invention relates to the field of spiral anchor foundation technology, specifically to a composite grouting spiral anchor foundation. Background Technology

[0002] A spiral anchor foundation is an anchoring structure that uses torque applied to the top of the anchor bolt to screw the anchor body into the soil layer. The anchor disc and the surrounding soil's end bearing and friction provide pull-out / bearing capacity. Due to its convenient construction, high pile formation efficiency, and reliable load-bearing capacity, it has been widely used in slope protection, pull-out anchoring, and foundation reinforcement engineering. To further improve the interfacial bonding performance between the anchor body and the surrounding soil and rock, pressure grouting is often performed after the spiral anchor is screwed into place in engineering practice. This allows the grout to diffuse and solidify around the anchor body, thereby improving local soil properties, enhancing the bond / interlocking between the anchor body and the soil, and improving the overall anchoring force and stability.

[0003] Patent CN216157690U discloses a novel spiral grouting anchor bolt. The anchor bolt body is a hollow rod with spiral fins on its outer periphery. Grouting holes are located on the anchor bolt body between adjacent spiral fins, connecting the grouting holes to the hollow inner cavity of the anchor bolt body. This allows grout to be directly discharged from the inner cavity of the anchor bolt through multiple grouting holes, reinforcing the surrounding soil. However, this type of hollow cavity lacks a confluence buffer and pressure equalization structure for the direct discharge path of the grout through multiple holes. During grouting, the grout tends to overflow preferentially from the orifice with the least resistance, causing grout discharge from other orifices to be delayed or even absent. This results in uneven grout distribution around the anchoring zone, affecting the uniformity of the reinforcement effect and the load-bearing stability.

[0004] Patent CN205742203U discloses a grouting pipe connection device for anti-buoyancy anchor construction. It achieves connection between the grouting pipe and the hollow drill rod / anchor by having an outer sleeve and an inner pipe arranged coaxially, with a through hole on the side wall of the inner pipe corresponding to the inner port of the connecting pipe on the inner wall of the outer sleeve. However, this connection method relies on precise alignment of the through hole and the port. Under conditions such as lowering, screwing in, and fluctuations in grouting pressure, even slight offsets or angular changes in the inner and outer components can easily lead to misalignment of the connection port, throttling, or even intermittent flow interruption, resulting in unstable grouting and uncontrollable distribution.

[0005] Therefore, there is an urgent need for a composite grouting spiral anchor foundation that can maintain stable connectivity during grouting and buffer and homogenize the grout flow to improve grouting uniformity, controllability and construction reliability. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the purpose of this invention is to provide a composite grouting spiral anchor foundation to solve the problems of unstable grouting channels and uneven pressure distribution.

[0007] To achieve the above objectives, the present invention provides a composite grouting spiral anchor foundation, comprising an internally hollow anchor rod and an anchor plate disposed outside the anchor rod, and further comprising: At least one outer cylinder is fitted around the middle and / or lower part of the outer periphery of the anchor rod, and a composite cavity is formed between the outer cylinder and the anchor rod; The grouting cylinder is coaxially disposed within the anchor bolt cavity; and A positioning component is disposed inside the grouting cylinder and defines the relative position between the grouting cylinder and the anchor rod to maintain stable communication between the grout outlet of the grouting cylinder and the annular groove opened on the anchor rod. The grout in the grouting cylinder enters the composite cavity through the grout outlet and the annular groove in sequence. After being converged, buffered and pressure homogenized in the composite cavity, it is discharged through the spray hole opened on the outer cylinder.

[0008] Furthermore, the composite cavity includes at least one set of cavities spaced apart along the axial direction of the outer cylinder; Each set of the cavity assembly includes a pressurizing cavity communicating with the annular groove and a pressure equalizing cavity communicating with the pressurizing cavity through a connecting hole; the pressure equalizing cavity is communicating with at least two spray holes opened on the outer cylinder, and each of the spray holes is distributed at intervals along the circumference of the outer cylinder.

[0009] Furthermore, several grout outlets are provided along the circumference of the grouting cylinder, and each grout outlet is aligned with the annular groove in axial height; when the spiral anchor foundation is grouting, the grout inlet at the top of the grouting cylinder is connected to the external grouting equipment, and the grout outlet at the bottom of the grouting cylinder is connected to the annular groove.

[0010] Furthermore, the annular groove has a rounded corner transition structure at its opening edge.

[0011] Furthermore, at least two sealing rings are provided on the outer periphery of the grouting cylinder, the sealing rings being sealed to the inner wall of the anchor rod and located on both axial sides of the grout outlet.

[0012] Furthermore, the positioning component includes: A rotating component, which is rotatably connected to the bottom end of the inner cavity of the grouting cylinder; A torque rod, fixedly connected to the rotating component and extending axially along the grouting cylinder and penetrating the top end of the grouting cylinder; and The positioning component is slidably disposed with the grouting cylinder by a guide limiting structure set at the grout outlet, and cooperates with the rotating component through a cam module; When the rotating component rotates, the positioning component is driven by the cam module to move along the path defined by the guide and limiting structure.

[0013] Furthermore, the cam module includes a cam groove formed along the circumference of the rotating member and a cam post disposed on the positioning member; The upper and lower groove surfaces of the cam groove are respectively provided with an upper sliding groove and a lower sliding groove that are arranged opposite to each other; the cam column is inserted between the upper sliding groove and the lower sliding groove, and moves along the groove trajectory of the cam groove under the clamping and guiding constraint of the upper sliding groove and the lower sliding groove when the rotating part rotates.

[0014] Furthermore, at least two drag-reducing slots are formed on the rotating component, each drag-reducing slot is connected to the upper sliding groove and / or the lower sliding groove, and the connecting opening of each drag-reducing slot is located in the guide area of ​​the upper sliding groove and / or the lower sliding groove that corresponds to each other in the axial direction.

[0015] Furthermore, the top end of the grouting cylinder is provided with a locking structure, the locking structure comprising: The positioning blocks are distributed circumferentially along the torque rod, the handle is set at the top of the torque rod, the pin hole is opened on the rod body below the handle, and the locking pin passes through the pin hole.

[0016] Furthermore, a locking groove is provided on the positioning block, and the locking pin passes through the pin hole and is embedded in the locking groove to achieve circumferential locking of the torque rod.

[0017] Beneficial Effects: Compared with existing technologies, this invention features an outer cylinder fitted around the middle and / or lower part of the hollow anchor rod, forming a composite cavity between the outer cylinder and the anchor rod. The grout enters the annular groove on the anchor rod through the grouting cylinder, then enters the composite cavity to homogenize the pressure before being discharged outwards. By connecting the annular groove with the formed composite cavity, the grout undergoes confluence buffering and pressure homogenization within the composite cavity before being discharged through the grouting holes, resulting in more uniform grout discharge from each grouting hole and improved grouting controllability and load-bearing stability. By setting a positioning component within the grouting cylinder to position and / or limit the position of the grouting cylinder relative to the anchor rod, the connection between the grouting cylinder and the anchor rod remains stable during lowering, screwing, and grouting pressure disturbances, improving the reliability of the grouting channel and construction controllability. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 A schematic diagram of a composite grouting spiral anchor foundation; Figure 2 This is a front view of a composite grouting spiral anchor foundation; Figure 3 for Figure 2 Sectional view along AA; Figure 4 for Figure 3 A magnified view of a section at point A in the middle; Figure 5 for Figure 4 A magnified view of a section at point B in the middle; Figure 6 This is a schematic diagram of the grouting cylinder structure; Figure 7 for Figure 6 A magnified view of a section at point C; Figure 8 for Figure 6 A magnified view of a section at point D; Figure 9 This is a partial schematic diagram of the positioning component; Figure 10 for Figure 9 A magnified view of a section at point E in the middle.

[0020] Explanation of reference numerals in the attached figures: 1-Anchor bolt, 11-Anchor bolt inner cavity, 12-Annular groove; 2-Anchor plate; 3-Outer cylinder, 31-Spraying hole, 32-Composite cavity, 321-Pressure boosting cavity, 322-Pressure equalization cavity, 323-Connecting hole; 4- Grouting cylinder, 41- Grout outlet, 42- Grout inlet, 43- Sealing ring; 5-Positioning component, 51-Rotating component, 52-Torque rod, 53-Positioning component, 54-Guide limiting structure, 55-Cam module, 551-Cam groove, 5511-Upper sliding groove, 5512-Lower sliding groove, 552-Cam column, 56-Drag reduction slot; 6-Locking structure, 61-Positioning block, 62-Handle, 63-Pin hole, 64-Locking pin, 65-Locking groove. Detailed Implementation

[0021] 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.

[0022] like Figures 1 to 4 and Figure 8As shown, this embodiment provides a composite grouting spiral anchor foundation, including an internally hollow anchor rod 1 and an anchor plate 2 disposed outside the anchor rod 1. It also includes: at least one outer cylinder 3, which is sleeved on the middle and / or lower part of the outer periphery of the anchor rod 1, and a composite cavity 32 is formed between the outer cylinder 3 and the anchor rod 1; a grouting cylinder 4, which is coaxially disposed in the inner cavity 11 of the anchor rod; and a positioning component 5, which is disposed in the grouting cylinder 4 and defines the relative position between the grouting cylinder 4 and the anchor rod 1 to maintain stable communication between the grout outlet 41 of the grouting cylinder 4 and the annular groove 12 opened on the anchor rod 1; wherein, the grout in the grouting cylinder 4 enters the composite cavity 32 through the grout outlet 41 and the annular groove 12 in sequence to complete the confluence buffering and pressure homogenization, and is discharged through the spray hole 31 opened on the outer cylinder 3.

[0023] During operation, the spiral anchor foundation is first screwed into the soil and rock mass, so that the anchor plate 2 forms a bearing interface and completes the anchoring position during the screwing process. Then, the grouting cylinder 4 is coaxially inserted into the inner cavity 11 of the anchor rod, and the position of the grouting cylinder 4 relative to the anchor rod 1 is positioned and / or limited by the positioning component 5, so that the grouting cylinder 4 is in a connected working position and stably connected with the anchor rod 1. After the positioning is completed, grouting begins. During the grouting process, the grout enters the composite cavity 32 between the outer cylinder 3 and the anchor rod 1 through the grout outlet 41 and the annular groove 12 on the anchor rod 1 in sequence, and is discharged outward through the spray hole 31 after the pressure is homogenized by the composite cavity 32. Since the positioning component 5 positions and limits the grouting cylinder 4, the connection state between the grouting cylinder 4 and the anchor rod 1 remains consistent during the grouting process, thereby improving the controllability and reliability of the grouting process.

[0024] In a preferred embodiment, such as Figures 1 to 4 As shown, the anchor rod 1 has a hollow structure, forming an internal cavity 11. The lower end of the anchor rod 1 is designed with a pointed structure to facilitate insertion into the soil. Multiple anchor discs 2 are arranged around the outer periphery of the anchor rod 1, spaced apart along the axial direction of the anchor rod 1, to provide a bearing and pull-out interface during the screwing process. Simultaneously, multiple outer cylinders 3 can be provided, respectively fitted into the middle and lower regions of the anchor rod 1. Each outer cylinder 3 and the anchor rod 1 enclose a composite cavity 32 to connect the circumferential flow of the annular groove 12 and distribute it outwards.

[0025] Based on the aforementioned outer cylinder 3 sleeve relationship, the anchor rod 1 has an annular groove 12 at the axial position corresponding to the outer cylinder 3, and the annular groove 12 is connected to the composite cavity 32 inside the outer cylinder 3. After the grout enters the annular groove 12 from the grouting cylinder, it first expands and converges circumferentially at the annular groove 12, and then enters the composite cavity 32 and is discharged outward to the surrounding rock and soil.

[0026] like Figure 5 , Figure 8 and Figure 9As shown, to improve the smoothness and reliability of the positioning component 53 entering the annular groove 12 area, the groove opening edge of the annular groove 12 is provided with a rounded transition structure. When the grouting cylinder 4 is lowered to a predetermined height, the rotatable torque rod 52 can be rotated to make the positioning component 53 in a pre-expanded state and form a guiding contact with the rounded transition structure; the positioning component 53 slides into the annular groove 12 under the guidance and gradually enters the position, thereby reducing the probability of collision, scratching or misalignment, and improving the consistency of the grout outlet 41 and the annular groove 12 docking.

[0027] like Figures 2 to 4 As shown, in a preferred embodiment, the composite cavity 32 between the outer cylinder 3 and the anchor rod 1 is divided into multiple cavity groups along the axial direction of the anchor rod 1; a partition structure is provided between adjacent cavity groups to make the cavity spaces of adjacent cavity groups independent of each other. Multiple outer cylinders 3 correspond to the middle and lower regions of the anchor rod 1 respectively; multiple cavity groups can be set inside each outer cylinder 3 to form an axially segmented independent outer row unit.

[0028] Specifically, such as Figure 2 and Figure 4 As shown, each cavity assembly includes a pressurizing cavity 321 connected to the annular groove 12 and a pressure equalizing cavity 322 connected to the pressurizing cavity 321 through a connecting hole 323. At least two slurry spraying holes 31 are provided on the outer cylinder 3, and these holes are connected to the pressure equalizing cavity 322, with each hole spaced apart along the circumference of the outer cylinder 3. After the slurry enters the pressurizing cavity 321, it enters the pressure equalizing cavity 322 through the connecting hole 323, where it is buffered and homogenized, and then discharged outwards through the circumferentially distributed spraying holes 31.

[0029] In a preferred embodiment, the pressure boosting chamber 321 and the pressure equalizing chamber 322 are structurally and functionally coordinated as follows: the pressure boosting chamber 321 is arranged in a circumferential confluence channel near the annular groove 12, and the effective volume of the chamber is relatively small, making it easier for the slurry to form a stable pressure; the connecting hole 323 forms an equivalent "throttling-pressure stabilizing" effect, so that the pressure fluctuation in the pressure boosting chamber 321 is weakened after passing through the connecting hole 323; the pressure equalizing chamber 322 has a relatively large effective volume and is connected to the slurry injection hole 31, which is used to redistribute and buffer the slurry supply pressure of the slurry injection hole 31, thereby improving the consistency of the slurry injection hole 31 in terms of both start-up and slurry volume.

[0030] like Figure 4 As shown, in a further preferred implementation, the connecting hole 323 is located at the upper connecting position of the pressurizing chamber 321, and the spraying hole 31 is located in the upper region of the pressure equalizing chamber 322. This arrangement has the following working mechanism: The connecting hole 323 is located at the upper part of the pressurizing chamber 321, which creates a "settling zone" at the lower part of the pressurizing chamber 321. Fine particles or locally highly viscous agglomerates that may be entrained in the slurry are more likely to remain in the lower part of the chamber and are less likely to directly enter the connecting hole 323, thus reducing the probability of blockage. At the same time, the upper location of the connecting hole 323 facilitates the upward discharge of gas or voids within the pressurizing chamber 321 during the slurry filling process. The pressurizing chamber 321 is more easily filled with slurry, pressure builds up faster, and the pressure subsequently entering the equalizing chamber 322 is more stable.

[0031] The spray nozzle 31 is located in the upper part of the pressure equalization chamber 322, which allows a buffer and settling space to be formed in the lower part of the pressure equalization chamber 322. Particles are less likely to accumulate near the spray nozzle 31, reducing the risk of blockage. Simultaneously, the pressure equalization chamber 322 is more likely to achieve a "fill first, then spray" state before spraying, which is beneficial for multiple spray nozzles 31 to start spraying synchronously when they approach the same pressure threshold, reducing the phenomenon of "some nozzles spraying first, some nozzles lagging behind". Furthermore, the upper location of the spray nozzle 31 also reduces the impact of backflow and suction at the moment of pump shutdown. The inertia of the slurry and the retention space in the lower part of the pressure equalization chamber 322 can provide a certain buffer, making the pressure change at the spray nozzle 31 smoother.

[0032] like Figure 3 , Figure 4 and Figure 8 As shown, under the premise that the above-mentioned cavity group achieves pressure building and pressure equalization, the grouting cylinder 4 needs to provide a stable and repeatable grouting interface in the anchor bolt 1 so that the grout enters the corresponding annular groove 12 at a predetermined height and is continuously supplied with grout. Therefore, the arrangement of the grout outlet 41 and the sealing window structure of the grouting cylinder 4 are further described below.

[0033] The grouting cylinder 4 is coaxially arranged in the inner cavity 11 of the anchor bolt. Several grout outlets 41 are circumferentially opened at the bottom of the grouting cylinder 4, and each grout outlet 41 corresponds one-to-one with the annular groove 12 of the anchor bolt in axial height. When the grouting cylinder 4 is in the connected working position, the grout outlets 41 are connected to the annular groove 12, and the grout enters the annular groove 12 from the grouting cylinder 4 through the grout outlets 41, then enters the composite cavity 32 and is discharged externally. A grout inlet 42 is provided at the top of the grouting cylinder 4, which is connected to external grouting equipment to continuously supply grout into the grouting cylinder 4. To prevent the grout from flowing around to a non-target axial height and to ensure that the grout only enters the annular groove 12 in the area of ​​the corresponding grout outlet 41, in this embodiment, sealing rings 43 are provided on both sides of the grout outlet 41 in the axial direction to form an axially closed connecting window within the anchor bolt 1.

[0034] like Figure 4 and Figure 8As shown, at least two sealing rings 43 are provided on the outer periphery of the grouting cylinder 4. The sealing rings 43 are sealed to the inner wall of the anchor bolt 1 and are located on both sides of the grout outlet 41, forming an axially closed connecting window in the area where the grout outlet 41 is located. The grout enters the annular groove 12 stably from the grouting cylinder 4 at this window, avoiding unexpected axial crossflow of the grout along the outer periphery of the grouting cylinder 4 and reducing the risk of leakage at the connection point. At the same time, this sealing window can make the grout entering the annular groove 12 more concentrated, which is conducive to forming a stable circumferential flow at the annular groove 12.

[0035] like Figure 1 , Figure 4 , Figure 5 and Figures 8 to 10 As shown, based on the above-mentioned connecting window, in order to ensure that the correspondence between the grout outlet 41 and the annular groove 12 does not shift during the lowering, adjustment and grouting pressure disturbance, this embodiment uses the positioning component 5 to position and limit the grouting cylinder 4, and uses the guide limiting structure 54 to constrain the movement posture and stroke of the positioning component 53.

[0036] The positioning component 5 is disposed inside the grouting cylinder 4 and includes a rotating component 51, a torque rod 52, and a positioning component 53. The rotating component 51 is rotatably connected to the bottom end of the inner cavity of the grouting cylinder 4; the torque rod 52 is fixedly connected to the rotating component 51 and extends axially along the grouting cylinder 4, penetrating the top end of the grouting cylinder 4; the positioning component 53 is slidably disposed on the grouting cylinder 4 through a guide limiting structure 54 in the grout outlet 41 area of ​​the grouting cylinder 4, and cooperates with the rotating component 51 through a cam module 55. When the rotating component 51 rotates, the positioning component 53 is driven by the cam module 55 to move along the path defined by the guide limiting structure 54.

[0037] like Figure 5 , Figure 9 and Figure 10 As shown, the guide limiting structure 54 is used to constrain the circumferential rotation of the positioning member 53 and limit its sliding stroke, so that the positioning member 53 slides smoothly in a predetermined direction, avoiding swaying and rubbing, thereby reducing frictional resistance and improving the consistency of positioning. The guide limiting structure 54 can be configured as a combination of a guide groove and a guide key, or as an equivalent guide structure of a guide surface, a guide post, and a limiting flange.

[0038] The cam module 55 includes a cam groove 551 formed on the rotating member 51 and a cam post 552 set on the positioning member 53. The upper and lower groove surfaces of the cam groove 551 are respectively provided with an upper sliding groove 5511 and a lower sliding groove 5512, which are respectively arranged opposite to each other; the cam post 552 is inserted between the upper sliding groove 5511 and the lower sliding groove 5512. When the rotating member 51 rotates, the cam post 552 moves accordingly within the cam groove 551, and moves along the channel trajectory of the cam groove 551 under the clamping and guiding constraints of the upper sliding groove 5511 and the lower sliding groove 5512, so that the positioning member obtains a stable and controlled motion trajectory; this structure can reduce the sway and off-center load of the cam post 552 within the groove, and improve the stability of the positioning action.

[0039] At least two drag-reducing slots 56 are formed on the rotating component 51. Each drag-reducing slot 56 communicates with the cam groove 551 and is located in the corresponding axial region of the upper sliding groove 5511 and / or the lower sliding groove 5512. The drag-reducing slots 56 are used to form bypass and buffer spaces in the local area of ​​the cam column 552 movement. When the slurry environment causes local high viscous resistance or fine particle compression, the drag-reducing slots 56 can provide pressure relief and fluid buffer space, reduce local peak resistance and torque fluctuations, thereby reducing the probability of the rotating component 51 jamming and improving the operability of positioning adjustment.

[0040] like Figures 6 to 9 As shown, the top of the grouting cylinder 4 is equipped with a locking structure 6. The locking structure 6 includes a positioning block 61 distributed circumferentially along the torque rod 52, a handle 62 located at the top of the torque rod 52, a pin hole 63 opened on the rod body below the handle 62, and a locking pin 64 that can pass through the pin hole 63. A locking groove 65 is opened on the positioning block 61; when the locking pin 64 passes through the pin hole 63 and is embedded in the locking groove 65, the handle 62 and the torque rod 52 are restricted circumferentially, the rotating part 51 is held at a set angle position, and the relative position of the positioning part 53 in the grout outlet 41 area is synchronously maintained. Thus, the grouting cylinder 4 can be adjusted to the connected working position and circumferential locking can be completed before grouting; the connected state remains consistent during grouting, avoiding misalignment or changes in flow area due to pressure disturbance.

[0041] As described above, this embodiment utilizes the continuous flow path structure of the grouting cylinder 4, annular groove 12, and composite cavity 32 to ensure that the grout undergoes circumferential convergence and buffering before entering the discharge port, and achieves pressure homogenization within the cavity group before being discharged through the spray hole 31. The segmented cavity group structure within the outer cylinder 3 makes the pressure transmission and flow distribution of multi-point discharge more consistent. The arrangement of the connecting hole 323 and the spray hole 31 on the upper part of the cavity makes it easier to achieve consistency in settlement, venting, and spraying. The positioning component 5 and the top locking structure 6 inside the grouting cylinder 4 ensure that the connection position between the grouting cylinder 4 and the anchor rod 1 is adjusted and maintained stably in place before grouting. Furthermore, the drag-reducing groove 56 and other structures reduce the fluctuation of motion resistance in the grout environment, thereby improving the overall uniformity, controllability, and construction reliability of grouting.

[0042] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A composite grouting spiral anchor foundation, comprising an internally hollow anchor rod (1) and an anchor plate (2) disposed outside the anchor rod (1), characterized in that, Also includes: At least one outer cylinder (3) is fitted around the middle and / or lower part of the outer periphery of the anchor rod (1), and a composite cavity (32) is formed between the outer cylinder (3) and the anchor rod (1). Grouting cylinder (4) is coaxially arranged in the inner cavity (11) of the anchor rod (1); as well as Positioning component (5) is set inside the grouting cylinder (4) and defines the relative position between the grouting cylinder (4) and the anchor rod (1) to maintain stable communication between the grout outlet (41) of the grouting cylinder (4) and the annular groove (12) opened on the anchor rod (1); The grout in the grouting cylinder (4) enters the composite cavity (32) through the grout outlet (41) and the annular groove (12) in sequence to complete the confluence buffer and pressure equalization, and then is discharged through the spray hole (31) opened on the outer cylinder (3).

2. The composite grouting spiral anchor foundation according to claim 1, characterized in that, The composite cavity (32) includes at least one set of cavities spaced apart along the axial direction of the outer cylinder (3); Each set of the cavity assembly includes a pressurizing cavity (321) communicating with the annular groove (12) and a pressure equalizing cavity (322) communicating with the pressurizing cavity (321) through a connecting hole (323). The spray holes (31) are distributed circumferentially along the outer cylinder (3), and the pressure equalization cavity (322) is connected to at least two spray holes (31).

3. The composite grouting spiral anchor foundation according to claim 1, characterized in that, The grout outlet (41) is provided with several outlets along the circumference of the grouting cylinder (4), and each outlet (41) is consistent with the annular groove (12) in axial height. When the spiral anchor foundation is grouting, the inlet (42) at the top of the grouting cylinder (4) is connected to the external grouting equipment, and the outlet (41) at the bottom of the grouting cylinder (4) is connected to the annular groove (12).

4. The composite grouting spiral anchor foundation according to claim 1, characterized in that, The annular groove (12) has a rounded corner transition structure at the groove edge.

5. The composite grouting spiral anchor foundation according to claim 1, characterized in that, At least two sealing rings (43) are provided on the outer periphery of the grouting cylinder (4). The sealing rings (43) are sealed to the inner wall of the anchor rod (1) and are located on both sides of the grout outlet (41).

6. The composite grouting spiral anchor foundation according to claim 1, characterized in that, The positioning component (5) includes: Rotating component (51), which is rotatably connected to the bottom end of the inner cavity of the grouting cylinder (4); Torque rod (52), which is fixedly connected to the rotating member (51) and extends axially along the grouting cylinder (4) and through the top end of the grouting cylinder (4); and The positioning component (53) is slidably disposed with the grouting cylinder (4) by a guide limiting structure (54) set at the grout outlet (41), and cooperates with the rotating component (51) through a cam module (55); When the rotating component (51) rotates, the positioning component (53) is driven by the cam module (55) to move along the path defined by the guide limiting structure (54).

7. The composite grouting spiral anchor foundation according to claim 6, characterized in that, The cam module (55) includes a cam groove (551) circumferentially opened along the rotating member (51) and a cam post (552) disposed on the positioning member (53). The upper and lower groove surfaces of the cam groove (551) are respectively provided with an upper sliding groove (5511) and a lower sliding groove (5512) that are arranged opposite to each other; the cam post (552) is inserted between the upper sliding groove (5511) and the lower sliding groove (5512). When the rotating part (51) rotates, the cam post (552) moves along the channel trajectory of the cam groove (551) under the clamping and guiding constraint of the upper sliding groove (5511) and the lower sliding groove (5512).

8. The composite grouting spiral anchor foundation according to claim 7, characterized in that, At least two drag-reducing slots (56) are provided on the rotating component (51). Each drag-reducing slot (56) is connected to the upper sliding groove (5511) and / or the lower sliding groove (5512). The connecting openings of each drag-reducing slot (56) are located in the guide areas of the upper sliding groove (5511) and / or the lower sliding groove (5512) that are corresponding to each other in the axial direction.

9. The composite grouting spiral anchor foundation according to claim 1, characterized in that, The top end of the grouting cylinder (4) is provided with a locking structure (6), the locking structure (6) comprising: The positioning block (61) is distributed circumferentially along the torque rod (52), the handle (62) is set on the top of the torque rod (52), the pin hole (63) is opened on the rod body below the handle (62), and the locking pin (64) passes through the pin hole (63).

10. The composite grouting spiral anchor foundation according to claim 9, characterized in that, The positioning block (61) has a locking groove (65), and the locking pin (64) passes through the pin hole (63) and is embedded in the locking groove (65) to achieve circumferential locking of the torque rod (52).

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