Construction device, construction method and structure of high-pressure jet grouting type spiral anchor composite foundation

Abstract

The invention relates to the technical field of electric power construction, in particular to a construction device, construction method and structure of a high-pressure rotary spraying type screw anchor composite foundation, which comprises a high-pressure rotary spraying type screw anchor, a high-pressure grouting system, a power screw-in system and a rotary joint. The situation that a nozzle is blocked is avoided, high-pressure rotary spraying is achieved when the anchor body spirally drills downwards, high-pressure rotary spraying cement slurry is used as a soil improvement means, disturbance related to anchor installation is relieved, the performance of soil in a disturbance area is enhanced, and the diameter of an anchor rod is greatly increased so that the buckling resistance can be improved; and meanwhile, the rotary jet grouting scheme of the large-diameter spiral anchor is considered, and application and popularization of the high-pressure rotary jet type spiral anchor composite foundation can be powerfully promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power construction, and in particular to a construction device, a construction method and a structure of a high-pressure rotary grouting type spiral anchor composite foundation. Background Art

[0002] China's rapid economic and technological development is fueling a rapidly growing demand for electricity. Construction of transmission lines across various voltage levels, including high voltage, ultra-high voltage, and ultra-high voltage, is underway. Foundation engineering is a crucial component of transmission line construction, contributing significantly to the overall cost, construction period, and labor consumption. Furthermore, foundation engineering is crucial to the operational safety of the entire line. If a tower foundation collapses, slides, or becomes dislodged, the entire line could be paralyzed.

[0003] State Grid Corporation of China is fully promoting fully mechanized construction technology for transmission lines. However, traditional transmission line tower foundations have a low mechanization rate and a long construction period. Furthermore, with the advancement of transmission line tower technology, traditional foundations are less suitable for some new tower types (such as narrow-base towers and multi-circuit self-supporting poles), and are prone to problems such as unreasonable stress and excessive specifications. Therefore, it is necessary to innovatively develop a series of new tower foundation types suitable for fully mechanized construction of transmission lines, targeting different geological conditions (such as mountainous areas, flatlands, and muddy areas), and different tower types (such as iron towers, self-supporting poles, and narrow-base towers).

[0004] In soft soil areas such as river networks and swamps, conventional transmission line tower foundation types include slab foundations, rigid step foundations, and cast-in-place pile foundations. Slab and rigid step foundations require significant excavation, require significant amounts of rebar and concrete, and are therefore expensive and require low mechanized construction rates. Cast-in-place pile foundations, however, often require larger diameters and lengths due to their bearing capacity requirements. However, due to road conditions and terrain restrictions, some tower locations are difficult for large machinery to reach, and smaller machinery cannot meet the required pile diameters. In response to these circumstances, a more rational foundation type is needed to reduce construction difficulty and workload, minimize damage to the natural environment, lower project costs, and facilitate mechanized construction.

[0005] Screw anchor foundations are made of steel and consist of one or more screw anchor plates welded to a steel pipe. They can be quickly installed by applying torque to the top of the screw anchor. This torque can be applied using an excavator drive assembly or a modified rotary drilling rig, resulting in a high degree of mechanization in foundation construction. Screw anchor foundations also offer the following advantages: 1. They can provide both uplift and downlift loads; 2. Bearing capacity can be assessed and verified using installation torque; 3. They can be installed at an angle; and 4. They provide bearing capacity immediately after installation. In the past decade, the use of screw anchor foundations for transmission line foundations has grown significantly. Screw anchors are primarily used in strong clay and sandy soils. However, the silt and mucky soils prevalent in Zhejiang Province are characterized by high water content, high porosity, low shear strength, and high disturbance resistance. When used in silt and mucky soils, screw anchors can suffer from issues such as lower-than-expected bearing capacity and poor corrosion resistance. Screw anchors often need to be installed at considerable depths to ensure adequate bearing capacity. However, the use of deep piles in tower foundations is less economical. At greater depths, the risk of encountering boulders during helical anchor installation increases significantly, sometimes rendering it impossible to drive the anchor into the ground. Furthermore, at greater depths, the risk of buckling under compression increases, requiring an increase in the diameter or wall thickness of the helical anchor rod, further reducing its economic viability. Helical anchor installation involves a certain amount of disturbance, and the highly disturbing nature of silt and muddy soils limits the anchor's full bearing capacity.

[0006] To address the aforementioned issues, Chinese patent application "CN109505305 A High-Pressure Jet-Jet Spiral Anchor Composite Foundation and Its Fabrication Method," published on March 22, 2019, proposes a high-pressure jet-jet spiral anchor composite foundation. This high-pressure jet-jet spiral anchor composite foundation consists of a jet-jet spiral anchor and a cement-soil outer pile surrounding and encasing the jet-jet spiral anchor. This novel foundation utilizes high-pressure jet-jet cement slurry as a soil conditioning method to mitigate disturbances associated with anchor installation, enhance soil properties within the disturbed area, and significantly increase the diameter of the anchor rod. Theoretical analysis indicates that the bearing capacity of a high-pressure jet-jet spiral anchor composite foundation is significantly improved compared to conventional spiral anchors. However, some of the concepts proposed in this invention have not been implemented, such as the problem of hole clogging after the vertical nozzle is installed, the lack of consideration for the detailed structure of the shotcrete pipe, and the lack of consideration for jet-jet grouting solutions for large-diameter spiral anchors. Consequently, the lack of corresponding construction machinery and methods for constructing high-pressure jet-jet spiral anchor composite foundations has prevented the feasibility of high-pressure jet-jet spiral anchor composite foundations from being verified, limiting their widespread application.

[0007] Based on this, this case is brought forward. Summary of the Invention

[0008] One of the purposes of the present invention is to provide a construction device for a high-pressure rotary jet spiral anchor composite foundation, to correct the points that cannot be implemented in the background technology scheme, to verify the feasibility of the high-pressure rotary jet spiral anchor composite foundation, and to promote the popularization and application of the high-pressure rotary jet spiral anchor composite foundation.

[0009] In order to achieve the above object, the technical solution of the present invention is as follows:

[0010] A construction device for a high-pressure rotary jet type spiral anchor composite foundation, comprising a high-pressure rotary jet type spiral anchor, a high-pressure grouting system, a power screwing system and a rotary joint. The high-pressure rotary jet type spiral anchor comprises a flange, an anchor rod, a spiral anchor plate, a grouting pipe and an anchor head.

[0011] The upper end of the anchor rod is fixed to the flange, and the flange is connected to the power screw-in system through a rotary joint. A grouting pipeline is provided in the anchor rod, and a grouting channel is provided in the rotary joint. One end of the grouting channel is connected to the output end of the high-pressure grouting system through a pipeline, and the other end of the grouting channel is connected to the grouting pipeline;

[0012] The anchor plate is arranged on the outer wall of the anchor rod, one end of the shotcrete pipe is located in the anchor rod and is connected to the grouting pipeline, the other end of the shotcrete pipe extends out of the anchor rod and the extended section is partially embedded in the anchor plate and partially located outside the anchor plate, the shotcrete pipe is provided with a normal injection nozzle and a tangential injection nozzle relative to the anchor rod, and the tangential injection nozzle is located on the side opposite to the precession direction;

[0013] The anchor head is fixed at the bottom of the anchor rod.

[0014] Furthermore, the high-pressure grouting system includes a high-pressure grouting machine and a cement slurry mixing barrel. The cement slurry mixing barrel provides the cement slurry required for injection by mixing cement and water. The high-pressure grouting machine provides high pressure for the cement slurry. Its input end extracts the cement slurry in the cement slurry mixing barrel through a pipeline, and its output end is connected to the grouting channel in the rotary joint through a pipeline.

[0015] Furthermore, the power precession system includes a drive head assembly, a robotic arm, a moving part and a power part. The drive head assembly is installed on the robotic arm, and the rotary joint is fixed on the rotation output end of the drive head assembly. The power part is used to provide power to the drive head assembly, the robotic arm and the moving part. The drive head assembly is used to apply torque to the high-pressure rotary jet spiral anchor. The robotic arm is used to adjust the installation angle of the high-pressure rotary jet spiral anchor, apply downward pressure or apply upward pulling force. The robotic arm and the power part are installed on the moving part, and the position is transferred through the moving part.

[0016] Furthermore, a shallow groove is provided on the surface where the flange is connected to the rotary joint, and a sealing ring is placed in the shallow groove.

[0017] Furthermore, the high-pressure rotary jet spiral anchor includes a baffle, which is fixed on the side of the spraying pipe facing the spiraling direction, and the length of the baffle is greater than the length of the spraying pipe exposed from the anchor rod.

[0018] Furthermore, the diameter of the anchor rod is less than 630 mm, the upper end of the anchor rod is open and hollow, the hollow portion of the anchor rod forms the grouting pipeline, and the anchor head adopts a conical head.

[0019] Furthermore, the diameter of the anchor rod is greater than or equal to 630 mm, and both ends of the anchor rod are open and hollow. The hollow part of the anchor rod is installed with a built-in pipe serving as a grouting pipeline through a fixing plate. The anchor head includes a small conical head plate and a large conical head plate that are vertically welded and fixed, and a conversion joint is provided between the rotary joint and the flange.

[0020] A second object of the present invention is to provide a structure of a high-pressure rotary grouting type spiral anchor composite foundation, including the above-mentioned high-pressure rotary grouting type spiral anchor.

[0021] A third object of the present invention is to provide a construction method for a high-pressure rotary grouting spiral anchor composite foundation, based on the above-mentioned high-pressure rotary grouting spiral anchor composite foundation construction device, comprising the following steps:

[0022] S1. Assemble the power screwing system and high-pressure grouting system, and position the high-pressure jet-jet screw anchor at the point to be driven;

[0023] S2. The high-pressure grouting system has been tested and passed the jet grouting pressure and sealing effect test;

[0024] S3. Preparation of cement slurry;

[0025] S4. A high-pressure grouting machine extracts cement slurry and pressurizes it into a high-pressure jet-jet screw anchor. The grouting pressure shall not exceed 2 MPa.

[0026] S5. After all nozzles of the high-pressure jet-jet screw anchor are screwed into the ground, increase the grouting pressure to above 20 MPa;

[0027] S6. Maintain a rotational speed of 5 to 15 rpm and an average descent speed of 5 to 15 cm / min. The average descent speed is controlled by rotating the high-pressure jet anchor to the specified depth, then reversing and rotating it upwards, repeatedly spraying the grout up and down, while simultaneously assisting with control by lifting or lowering the excavator arm until the high-pressure jet anchor reaches the target depth.

[0028] S7. After reaching the target depth, first stop the screwing, then stop the grouting, and separate the upper power screwing system and high-pressure grouting system from the high-pressure rotary grouting screw anchor at the flange;

[0029] S8. Connect the next high-pressure jet-jet spiral anchor to the upper power screwing system and high-pressure grouting system, and move it to the point to be driven into position through the moving part;

[0030] S9. Repeat steps S2 to S7 until the last high-pressure jet-jet spiral anchor is completed;

[0031] S10. High pressure grouting system cleaning;

[0032] S11. After the high-pressure jet-grouting spiral anchor composite foundation has solidified for a certain period of time, drill the jet-grouting solid rock core for indoor mechanical and physical tests, or conduct a foundation static load test. After it meets the design requirements, the superstructure construction can be carried out.

[0033] Furthermore, in step S6, when the diameter of the anchor rod is greater than or equal to 630 mm, the high-pressure rotary jet spiral anchor is only screwed into the depth of one pitch at a time. After reaching the specified depth, the high-pressure rotary jet spiral anchor is reversed. After the slurry volume within the depth range reaches the design value, it is rotated downward in the forward direction to the depth of one pitch until the high-pressure rotary jet spiral anchor is screwed to the target depth.

[0034] The advantages of the present invention are: it corrects the points that cannot be implemented in the invention of the Chinese patent "CN109505305 A High-pressure rotary jet spiral anchor composite foundation and its manufacturing method" with a publication date of 2019.03.22, and develops relevant equipment to verify the feasibility of the revised new high-pressure rotary jet spiral anchor composite foundation. For example, the vertical nozzle is eliminated, and two types of nozzles, tangential and normal, are designed to avoid nozzle clogging. High-pressure rotary jetting is achieved when the anchor body spirally drills downward, and high-pressure rotary jetting cement slurry is used as a means of soil improvement to reduce disturbances associated with anchor installation, enhance soil properties in the disturbed area, and greatly increase the diameter of the anchor rod to improve anti-buckling ability. At the same time, the rotary jet grouting scheme for large-diameter spiral anchors is considered, which can effectively promote the promotion and application of high-pressure rotary jetting spiral anchor composite foundations. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic diagram of the construction device in the embodiment;

[0036] Figure 2 Schematic diagram of the structure of a small-diameter high-pressure rotary jet spiral anchor in an embodiment;

[0037] Figure 3 for Figure 2 A magnified schematic diagram of part A in FIG;

[0038] Figure 4 for Figure 2 Schematic cross-sectional view of ;

[0039] Figure 5 Schematic diagram of the structure of a large-diameter high-pressure rotary jet spiral anchor in an embodiment;

[0040] Figure 6 for Figure 5 An enlarged schematic diagram of part B;

[0041] Figure 7 for Figure 5 Schematic cross-sectional view of ;

[0042] Figure 8 for Figure 5 Schematic diagram of the internal structure;

[0043] Figure 9 A schematic diagram of a conversion joint between a large-diameter, high-pressure jet-jet spiral anchor and a rotary joint;

[0044] Figure 10 A physical diagram of the construction device in the embodiment;

[0045] Figure 11 This is a physical picture of a small-diameter, high-pressure jet-jet spiral anchor in the embodiment;

[0046] Figure 12 Schematic diagram of the position of the small-diameter high-pressure rotary jet type spiral anchor tangential injection nozzle and the baffle in the embodiment;

[0047] Figure 13 This is a physical picture of a large-diameter, high-pressure jet-jet spiral anchor in the embodiment;

[0048] Figure 14 This is a physical diagram of the interior of a large-diameter, high-pressure jet-jet spiral anchor in an embodiment;

[0049] Description of labels

[0050] 1. High-pressure rotary jet screw anchor; 2. Rotary jet slurry; 3. Rotary joint; 4. Conversion flange between the rotary joint and the power precession system; 5. Drive head assembly; 6. Excavator; 7. Forearm; 8. Connecting pipes; 9. High-pressure grouting machine; 10. Cement slurry mixing drum; 11. Flange; 12. Anchor rod; 13. Anchor plate; 14. Shotcrete pipe; 15. Baffle; 16. Conical anchor head; 17. Normal jet nozzle; 18. Tangential jet nozzle; 19. Bolt hole; 20. Shallow groove; 21. Hollow part of small-diameter high-pressure rotary jet screw anchor; 22. Small conical head plate; 23. Large conical head plate; 24. Transition pipe; 25. Internal pipe; 26. Fixing plate; 27. Conversion joint. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the embodiments. It should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. used herein to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0052] This embodiment proposes a construction device for a high-pressure rotary grouting spiral anchor composite foundation, such as Figures 1 to 14 As shown, it includes a high-pressure rotary jet spiral anchor 1, a high-pressure grouting system, a power screw-in system and a rotary joint 3.

[0053] The high-pressure rotary grouting spiral anchor 1 comprises a flange 11, an anchor rod 12, a spiral anchor plate 13, a grouting pipe 14, and an anchor head. The upper end of the anchor rod 12 is integrally formed with the flange 11, which can be connected to the power precession system via a rotary joint 3. A grouting pipeline is provided within the anchor rod 12, and a grouting channel is provided within the rotary joint 3. One end of the grouting channel is connected to the output end of the high-pressure grouting system via a connecting pipe 8, and the other end of the grouting channel is connected to the grouting pipeline. The anchor plate 13 is disposed on the outer wall of the anchor rod 12. One end of the grouting pipe 14 is located within the anchor rod 12 and connected to the grouting pipe. The other end of the grouting pipe 14 extends out of the anchor rod 12, with the extended section partially embedded in the anchor plate 13 and partially located outside the anchor plate 13. The grouting pipe 14 is provided with a normal spray nozzle 17 and a tangential spray nozzle 18 relative to the anchor rod 12, with the tangential spray nozzle 18 located on the side away from the precession direction. The anchor head is fixed to the bottom of the anchor rod 12.

[0054] The high-pressure rotary jet spiral anchor 1 can be divided into a large-diameter (anchor rod 12 diameter is greater than or equal to 630 mm) high-pressure rotary jet spiral anchor and a small-diameter (anchor rod 12 diameter is less than 630 mm) high-pressure rotary jet spiral anchor.

[0055] like Figures 2 to 4 、 Figures 11 to 12 As shown, it is a schematic diagram of the structure of a small-diameter high-pressure rotary jet spiral anchor. Since the anchor rod 12 of the small-diameter high-pressure rotary jet spiral anchor 1 has a small diameter, the upper end of the anchor rod 12 is open and hollow. The hollow part of the anchor rod 12 directly forms the grouting pipeline, and the anchor head adopts a conical anchor head 16.

[0056] like Figures 5 to 9 、 Figures 13 and 14As shown in the figure, it is a schematic diagram of the structure of a large-diameter high-pressure rotary jet type spiral anchor. The diameter of the anchor rod 12 of the large-diameter high-pressure rotary jet type spiral anchor 1 is large, and the torque required for screwing is huge. The domestically produced drive head assembly 5 cannot provide sufficient torque, so the anchor rod 12 is designed to have a hollow cylindrical structure with both ends open to reduce the torque required for screwing. Therefore, it is impossible to adopt the solution of directly using the internal hollow part as a grouting pipeline. In this embodiment, a steel built-in pipe 25 is set inside the anchor rod 12 of the large-diameter high-pressure rotary jet type spiral anchor as a grouting pipeline. The built-in pipe 25 is fixed in position by a fixing plate 26 to prevent the soil from entering from the inside of the anchor rod 12 and damaging the built-in pipe 25. The upper end of the built-in pipe is connected to the rotary joint 3 through a transition pipe 24, and the lower end of the built-in pipe 25 is connected to the grouting pipe 14 on both sides through a tee. The large-diameter high-pressure rotary jet spiral anchor uses a small conical head plate 22 and a large conical head plate 23 vertically welded as the anchor head. On the one hand, it plays a role in breaking the ground, further reducing the torque required for screwing. On the other hand, the three-way weld at the bottom of the built-in pipe 25 of the large conical head plate 23 plays a role in fixing the built-in pipe 25.

[0057] The high-pressure rotary grouting spiral anchor 1 is directly connected to the rotary joint 3 by bolts. For large-diameter high-pressure rotary grouting spiral anchors, since the flange diameter of the spiral anchor is larger than the flange diameter of the rotary joint 3, a conversion joint 27 (i.e., conversion flange, can be seen) needs to be added. Figure 9 ).

[0058] Preferably, a shallow groove 20 is provided on the surface where the flange 11 is connected to the rotary joint 3, and a sealing ring is placed in the shallow groove 20 to play a sealing role.

[0059] like Figure 3 、 Figure 4 、 Figure 6 、 Figure 7 and Figure 12 As shown, the grouting pipe 14 contains one normal jet nozzle 17 and two tangential jet nozzles 18. A portion of the grouting pipe 14 is embedded in the anchor plate 13 to fix and protect the grouting pipe 14 during the construction process, and a portion is located outside the anchor plate 13 to increase the ground-breaking range and enhance the grouting effect. The normal jet nozzle 17 is mainly used to spray slurry to expand the diameter of the spiral anchor, and the tangential jet nozzle 18 is mainly used to perform rotary jet reinforcement on the soil within the projection range of the anchor plate 13. The high-pressure rotary jet spiral anchor 1 of this embodiment also includes a baffle 15. The baffle 15 is located on the side of the rotation direction of the lower grouting pipe 14, and the length of the baffle 15 is greater than the length of the grouting pipe 14 exposed from the anchor rod 12, which plays a role in protecting the grouting pipe 14 and preventing the normal jet nozzle 17 from being blocked by the side soil.

[0060] like Figure 1As shown, the high-pressure grouting system includes a high-pressure grouting machine 9 and a cement slurry mixing barrel 10. The cement slurry mixing barrel 10 provides the cement slurry required for injection by mixing cement and water. The high-pressure grouting machine 9 provides high pressure for the cement slurry. Its input end extracts the cement slurry in the cement slurry mixing barrel 10 through a pipeline, and its output end is connected to the grouting channel in the rotary joint 3 through a pipeline. The high-pressure grouting system injects the cement slurry into the high-pressure rotary jet screw anchor 1 under high pressure. The high-pressure rotary jet screw anchor 1 rotates and sprays the high-pressure rotary jet slurry. After the high-pressure slurry impacts the surrounding soil, it can destroy the original soil structure and mix with the surrounding soil to form cement soil. High-pressure rotary jet cement slurry is used as a means of soil improvement to reduce the disturbance associated with anchor installation, enhance the soil properties in the disturbed area, and greatly increase the diameter of the anchor rod 12 to improve the anti-buckling ability.

[0061] The power precession system includes a drive head assembly 5 and an excavator 6. The drive head assembly 5 is connected to the excavator 6 via an excavator arm 7, a swing frame, an oil pipe, etc. The hydraulic system of the excavator 6 provides power to the drive head assembly 5 through the oil pipe. The drive head assembly 5 applies torque to the high-pressure rotary grouting screw anchor 1 to screw the high-pressure rotary grouting screw anchor 1 into the ground. The rotary joint 3 and the conversion flange 4 play the role of transmitting torque in this process. By adjusting the excavator 6 arm and the excavator arm 7, the installation angle of the high-pressure rotary grouting screw anchor 1 can be adjusted, downward pressure can be applied to promote the screwing of the screw anchor, or upward pulling force can be applied to slow down or stop the screw anchor from rotating upward, or even cooperate with the screw anchor to rotate in reverse. In addition, after constructing a high-pressure rotary grouting screw anchor 1, the excavator 6 can be started to quickly move to another pile location.

[0062] The power precession system controls the precession speed and depth of the high-pressure rotary jet spiral anchor 1, and the high-pressure grouting system controls the grouting pressure and slurry flow of the high-pressure rotary jet spiral anchor 1. The two work together to complete the construction of the high-pressure rotary jet spiral anchor 1 composite foundation. The construction includes the following steps:

[0063] S1. Power screw precession system assembly, high-pressure grouting system assembly, high-pressure rotary jet spiral anchor 1 to be driven into place;

[0064] S2. Pump water and pressurize the high-pressure grouting machine 9 to test the jetting pressure and sealing effect. If the pressure reaches 20 MPa or above and is maintained for 30 minutes without sealing failure, the test passes. If the pressure cannot be reached, increase the speed of the high-pressure grouting machine 9 or replace the nozzle with a smaller diameter and debug until the target pressure value is reached.

[0065] S3. Pour cement and water into a high-speed mixing drum at a certain ratio and stir at high speed. After stirring, pour the cement into the lower cement mixing drum through a pipe and stir to maintain the uniformity of the mixture. At the same time, continue to pour cement and water into the higher cement mixing drum and stir.

[0066] S4 high-pressure grouting machine 9 extracts pressurized cement slurry and injects it into the high-pressure jet-jet spiral anchor 1, the grouting pressure is not higher than 2MPa;

[0067] S5. After all nozzles of the high-pressure jet-jet spiral anchor 1 are screwed into the ground below, the grouting pressure is increased to more than 20MPa;

[0068] S6. Maintain a rotation speed of 5 to 15 rpm and an average descent speed of 5 to 15 cm / min. The average descent speed is controlled by screwing the high-pressure jet-jet spiral anchor 1 to the specified depth, then reversing and rotating it back and forth, and repeatedly spraying the grout up and down. At the same time, auxiliary control is performed by lifting or pressing the excavator 6 arm 7 until the high-pressure jet-jet spiral anchor 1 is screwed to the target depth.

[0069] In this step, when the diameter of the anchor rod 12 is greater than or equal to 630 mm (i.e., a large-diameter high-pressure rotary jet type spiral anchor), the high-pressure rotary jet type spiral anchor 1 is only screwed into the depth of one pitch at a time. After reaching the specified depth, the high-pressure rotary jet type spiral anchor 1 is reversed, and after the slurry volume in the depth range reaches the design value, it is screwed down to the depth of one pitch until the high-pressure rotary jet type spiral anchor 1 is screwed to the target depth. The reason is that after the large-diameter high-pressure rotary jet type spiral anchor is lowered to a certain depth, the excavator 6 cannot lift it up by lifting the small arm 7 due to its own weight. Since the mud is in a liquid state, it cannot provide sufficient self-attack force to reverse the large-diameter spiral anchor, thereby being unable to realize repeated grouting up and down, so it is necessary to only screw into the depth of one pitch each time.

[0070] S7 after reaching the target depth, first stop the screw into, then stop grouting, the upper power screw into the system and high-pressure grouting system and high-pressure rotary jet spiral anchor 1 separated at the flange 11;

[0071] S8. The next high-pressure jet-jet spiral anchor 1 is connected to the upper power screwing system and the high-pressure grouting system, and is moved to the point to be driven into position by the mobile portion;

[0072] S9 repeat steps S2 to S7 until the last high-pressure jet-jet spiral anchor 1 is completed;

[0073] S10 high-pressure grouting system cleaning, high-pressure grouting machine 9 pumping water to clean the mud in the pipe, use a mud pump to clean the residual mud in the cement mixing barrel, use a pump to pump water to clean the cement mixing barrel;

[0074] S11. After the high-pressure jet-grouting spiral anchor 1 composite foundation solidifies for a certain period of time, drill the jet-grouting solid rock core for indoor mechanical and physical tests, or conduct a foundation static load test. After it meets the design requirements, the superstructure construction can be carried out.

[0075] The above embodiments are only used to illustrate the concept of the present invention, and are not intended to limit the protection of the present invention. Any non-substantial changes to the present invention using this concept should fall within the scope of protection of the present invention.

Claims

1. A construction device for a high-pressure rotary grouting type spiral anchor composite foundation, comprising a high-pressure rotary grouting type spiral anchor, a high-pressure grouting system, a power screw-in system and a rotary joint, characterized in that: The high-pressure rotary spray type spiral anchor comprises a flange, an anchor rod, a spiral anchor plate, a spraying pipe and an anchor head; The upper end of the anchor rod is fixed to the flange, and the flange is connected to the power screw-in system through a rotary joint. A grouting pipeline is provided in the anchor rod, and a grouting channel is provided in the rotary joint. One end of the grouting channel is connected to the output end of the high-pressure grouting system through a pipeline, and the other end of the grouting channel is connected to the grouting pipeline; The anchor plate is arranged at the outer wall of the anchor rod, one end of the shotcrete pipe is located in the anchor rod and communicated with the grouting pipeline, the other end of the shotcrete pipe extends out of the anchor rod and the extended section is partially embedded in the anchor plate and partially located outside the anchor plate, the shotcrete pipe is provided with a normal injection nozzle and a tangential injection nozzle relative to the anchor rod, and the tangential injection nozzle is located on the side opposite to the screwing direction; The anchor head is fixed at the bottom of the anchor rod.

2. A construction device for a high-pressure rotary grouting type spiral anchor composite foundation as claimed in claim 1, characterized in that: The high-pressure grouting system includes a high-pressure grouting machine and a cement slurry mixing barrel. The cement slurry mixing barrel provides cement slurry required for injection by mixing cement and water. The high-pressure grouting machine provides high pressure for the cement slurry. Its input end draws cement slurry in the cement slurry mixing barrel through a pipeline, and its output end is connected to the grouting channel in the rotary joint through a pipeline.

3. A construction device for a high-pressure rotary grouting type spiral anchor composite foundation as claimed in claim 1, characterized in that: The power precession system includes a drive head assembly, a mechanical arm, a moving part and a power part. The drive head assembly is installed on the mechanical arm, and the rotary joint is fixed on the rotating output end of the drive head assembly. The power part is used to provide power to the drive head assembly, the mechanical arm and the moving part. The drive head assembly is used to apply torque to the high-pressure rotary jet spiral anchor. The mechanical arm is used to adjust the installation angle of the high-pressure rotary jet spiral anchor, apply downward pressure or apply upward pulling force. The mechanical arm and the power part are installed on the moving part, and the position is transferred through the moving part.

4. A construction device for a high-pressure rotary grouting type spiral anchor composite foundation as claimed in claim 1, characterized in that: A shallow groove is arranged on the surface where the flange is connected to the rotary joint, and a sealing ring is placed in the shallow groove.

5. A construction device for a high-pressure rotary grouting type spiral anchor composite foundation as claimed in claim 1, characterized in that: The high-pressure rotary jetting screw anchor comprises a baffle, which is fixed on one side of the shotcrete pipe facing the screwing direction, and the length of the baffle is greater than the length of the shotcrete pipe exposed from the anchor rod.

6. A construction device for a high-pressure rotary grouting type spiral anchor composite foundation as claimed in any one of claims 1 to 5, characterized in that: The diameter of the anchor rod is less than 630 mm, the upper end of the anchor rod is open and hollow, the hollow part of the anchor rod forms the grouting pipeline, and the anchor head adopts a conical head.

7. A construction device for a high-pressure rotary grouting type spiral anchor composite foundation as claimed in any one of claims 1 to 5, characterized in that: The diameter of the anchor rod is greater than or equal to 630 mm, and the two ends of the anchor rod are open and hollow. The hollow part of the anchor rod is installed with a built-in pipe serving as a grouting pipeline through a fixing plate. The anchor head includes a small conical head plate and a large conical head plate that are vertically welded and fixed. A conversion joint is arranged between the rotating joint and the flange.

8. A structure of a high-pressure jet-sprayed spiral anchor composite foundation, characterized in that: It comprises the high-pressure rotary jet spiral anchor as described in any one of claims 1 to 7.

9. A construction method for a high-pressure rotary grouting spiral anchor composite foundation, characterized in that: The construction device of the high-pressure rotary grouting type spiral anchor composite foundation according to any one of claims 1 to 7 comprises the following steps: S1. Assemble the power screwing system, assemble the high-pressure grouting system, and put the high-pressure rotary jet screw anchor in place at the point to be driven; S2. The high pressure grouting system has been tested and passed the jetting pressure and sealing effect test; S3. Cement slurry preparation; S4. The high-pressure grouting machine extracts cement slurry and pressurizes it into the high-pressure rotary jet screw anchor. The grouting pressure is not higher than 2MPa; S5. After all nozzles of the high-pressure jet-jet screw anchor are screwed into the ground, the grouting pressure is increased to above 20 MPa; S6. Maintain the rotation speed at 5 to 15 rpm and the average descent speed at 5 to 15 cm / min. The average descent speed is controlled by repeatedly spraying the high-pressure rotary grouting screw anchor up and down after the high-pressure rotary grouting screw anchor is screwed to the specified depth, and then reversed and rotated up. At the same time, auxiliary control is performed by lifting or pressing down the excavator arm until the high-pressure rotary grouting screw anchor is screwed to the target depth; S7. After reaching the target depth, first stop the screwing and then stop the grouting, and separate the upper power screwing system and the high-pressure grouting system from the high-pressure rotary jet screw anchor at the flange; S8. Connect the next high-pressure rotary jet screw anchor to the upper power screwing system and the high-pressure grouting system, and move it to the point to be driven into place through the moving part; S9. Repeat steps S2 to S7 until the last high-pressure jet-sprayed spiral anchor is constructed; S10. High pressure grouting system cleaning; S11. After the high-pressure jet-jet spiral anchor composite foundation solidifies for a certain period of time, drill the jet-jet solid rock core for indoor mechanical and physical tests, or conduct a foundation static load test. After it meets the design requirements, the superstructure is constructed.

10. A construction method for a high-pressure rotary grouting type spiral anchor composite foundation as claimed in claim 9, characterized in that: In step S6, when the diameter of the anchor rod is greater than or equal to 630 mm, the high-pressure rotary jet spiral anchor is only screwed into the depth of one pitch at a time. After reaching the specified depth, the high-pressure rotary jet spiral anchor is reversed. After the slurry volume in the depth range reaches the design value, it is then screwed downward to the depth of one pitch until the high-pressure rotary jet spiral anchor is screwed to the target depth.

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