Variable-diameter high-pressure jet grouting pile

Abstract

According to the variable-diameter high-pressure jet grouting pile, an effective solution is correspondingly provided for a drill bit and a guniting blade, and the problems that the diameter of an existing high-pressure jet grouting pile cannot be adaptively adjusted according to the stratum condition, the grout outlet end is prone to being blocked, the fusion degree of cement and soil is not high, and the guniting blade is prone to being wound are expected to be solved. Comprising a high-pressure jet grouting drilling machine, the high-pressure jet grouting drilling machine is connected with a slurry feeding system, a hollow working drill shaft is arranged at the working end of the high-pressure jet grouting drilling machine, a variable-diameter drill bit is connected to the front end of the working drill shaft, and a group of continuously extending spiral stirring wings, a plurality of groups of stirring blades and a slurry spraying system are arranged outside the working drill shaft.

Description

Technical Field

[0001] The present application relates to the field of civil engineering construction, and specifically proposes a novel variable-diameter high-pressure jet grouting pile. Background Art

[0002] In recent years, with the continuous development of underground space, such as subways, underground parking lots, supermarkets or pedestrian walkways, many deep foundation pit projects have been generated, which are increasing in both scale and depth. At the same time, many deep foundation pit engineering problems that need to be solved urgently have inevitably emerged. The problems caused by the excavation of foundation pit projects are not only the changes in the stress field and displacement field of the supporting structure and the surrounding environment, but also a complex seepage field problem. In order to ensure the stability and safety of the foundation pit and its surrounding environment, water-stop curtains are generally adopted. Water-stop curtains are the general term for the water-stop series outside the main body of the project. They are continuous water-stop bodies used to prevent or reduce the inflow of groundwater from the side walls and bottom of the foundation pit into the foundation pit.

[0003] The equipment commonly used in the construction of water-stop curtains in the prior art usually includes high-pressure rotary jet piles and deep mixing piles. Although the high-pressure rotary jet pile technology has low drilling resistance and low cement consumption, its design and use defects are also obvious. For example, the excavation depth range of foundation pits in some areas varies greatly due to the large stratum changes, and the high-pressure rotary jet pile machine cannot adjust the diameter of the high-pressure rotary jet pile according to the stratum changes. Moreover, the high-pressure slurry discharge port is often set near the blades or above the mixing blades, which is easy to be blocked during the cement soil mixing process, which has a great impact on the construction progress; the single discharge port set at the bottom makes the discharge uneven, that is, the degree of fusion between cement and soil is not high; it does not have a cleaning effect on the discarded drainage boards and other debris contained in the foundation, and often forms entanglement during piling. The mixing blades are entangled and further affect the cutting and mixing of the cement soil, resulting in construction difficulties and seriously affecting the construction quality.

[0004] In view of this, this patent application is proposed. Summary of the invention

[0005] The variable diameter high-pressure rotary jet piles described in the present application aim to solve the problems existing in the above-mentioned prior art and to propose effective solutions for the drill bit and the grouting blades, in order to solve the many problems that the existing high-pressure rotary jet piles cannot adaptively adjust the diameter according to the formation conditions, the slurry outlet end is easily blocked, the fusion degree between cement and soil is not high, and the grouting blades are easily entangled.

[0006] To achieve the above-mentioned design purpose, the variable-diameter high-pressure rotary jet pile includes a high-pressure rotary jet drilling rig, which is connected to a slurry delivery system. A hollow working drill shaft is arranged at the working end of the high-pressure rotary jet drilling rig, a variable-diameter drill bit is connected to the front end of the working drill shaft, and a group of continuously extending and distributed spiral stirring wings and an array of stirring blades, as well as a grouting system are arranged outside the working drill shaft; the slurry delivery system is connected to the top of the working drill shaft, and includes at least one group of cement slurry delivery pipes, at least one group of low water-cement ratio cement slurry delivery pipes, at least one group of high-pressure water delivery pipes and at least one group of high-pressure gas delivery pipes, which are externally connected to a cement mixer and a high-pressure water tank device and extend vertically inwardly in the hollow cavity of the working drill shaft; the grouting system includes a cement slurry spraying device connected to the cement slurry delivery pipe, a low water-cement ratio cement slurry spraying device connected to the low water-cement ratio cement slurry delivery pipe, a high-pressure water jetting device connected to the high-pressure water delivery pipe, and a high-pressure gas jetting device connected to the high-pressure gas delivery pipe.

[0007] An array of cement slurry spraying devices is symmetrically connected to both sides of the outside of the working drill shaft. Each group of cement slurry spraying devices is provided with a cement slurry storage chamber and several sub-compartment cement slurry storage chambers. A cement slurry sub-compartment circulation hole for circulating cement slurry is provided between two adjacent sub-compartment cement slurry storage chambers. At least one cement slurry spraying port is provided at the outer end of each sub-compartment cement slurry storage chamber, and a cement slurry sub-compartment partition is provided between two adjacent cement slurry spraying ports.

[0008] The plurality of low water-cement ratio cement slurry spraying devices are symmetrically distributed on both sides of the outside of the working drill shaft, each group of cement slurry spraying devices and the adjacent low water-cement ratio cement slurry spraying devices are at the same vertical height of the working drill shaft, and the angle between the two in the horizontal section of the working drill shaft is 90°; each group of low water-cement ratio cement slurry spraying devices includes a low water-cement ratio cement slurry storage chamber and a low water-cement ratio cement slurry spraying port that are interconnected.

[0009] The plurality of high-pressure water jet devices are symmetrically distributed on both sides of the outside of the working drill shaft and are all located vertically below the low water-cement ratio cement slurry spraying device; each group of high-pressure water jet devices and an adjacent group of low water-cement ratio cement slurry spraying devices are in the same vertical section of the working drill shaft, and the angle between each group of high-pressure water jet devices and an adjacent group of cement slurry spraying devices in the same horizontal section of the working drill shaft is 90°; each group of high-pressure water jet devices includes a high-pressure water storage chamber and high-pressure water spray holes that are interconnected, and the high-pressure water spray holes are distributed upward along the outer wall of the working drill shaft at an angle of 10 to 25°.

[0010] The plurality of high-pressure gas injection devices are symmetrically distributed on both sides of the outside of the working drill shaft, and are all located vertically below the high-pressure water spraying device, and are in the same vertical section of the working drill shaft as the cement slurry spraying device; each group of high-pressure gas injection devices includes a high-pressure gas compression chamber and a high-pressure gas injection hole that are interconnected, and the high-pressure gas injection holes are distributed upward along the outer wall of the working drill shaft at an angle of 15 to 45 degrees.

[0011] A shotcrete gear control system is arranged at the overall upper end of the shotcrete system, and the shotcrete gear control system includes 2 groups of shotcrete rotating gears and 2 groups of low water-cement ratio cement slurry shotcrete rotating gears, and the adjacent shotcrete rotating gears and low water-cement ratio cement slurry shotcrete rotating gears are meshed; the 2 groups of cement slurry delivery pipes respectively pass through the vertical gaps of the 2 groups of shotcrete rotating gears, but the cement slurry delivery pipes do not rotate with the shotcrete rotating gears; the 2 groups of low water-cement ratio cement slurry delivery pipes respectively pass through the vertical gaps of the 2 groups of low water-cement ratio cement slurry shotcrete rotating gears, but the low water-cement ratio cement slurry delivery pipes do not rotate with the low water-cement ratio cement slurry shotcrete rotating gears; a low water-cement ratio cement slurry delivery pipe baffle for opening or closing the low water-cement ratio cement slurry delivery pipe is arranged on one side of the low water-cement ratio cement slurry shotcrete rotating gear.

[0012] One end of a baffle control rod is connected to one side of the shotcrete rotating gear, and the other end of the baffle control rod is connected to a low water-cement ratio cement slurry shotcrete connecting ring. The low water-cement ratio cement slurry shotcrete connecting ring is a hollow ring and the baffle control rod can rotate with the shotcrete rotating gear; the bottom of the low water-cement ratio cement slurry conveying pipe baffle is connected to the low water-cement ratio cement slurry shotcrete rotating gear through a group of springs.

[0013] The variable diameter drill bit is composed of a bottom drilling drill bit and a variable diameter cutting drill disc, and the variable diameter cutting drill disc is arranged at the upper end of the bottom drilling drill bit; the variable diameter cutting drill disc includes a variable diameter cutting drill disc rotating shaft and a fixed drill disc ring, the axial ends of the variable diameter cutting drill disc rotating shaft are respectively fixedly connected to the bottom drilling drill bit and the vertical direction of the working drill shaft, the circumferential direction of the fixed drill disc ring is fixedly connected to the inner wall of the bottom drilling drill bit, and a group of fixed drill shafts are fixedly connected in the horizontal radial direction between the variable diameter cutting drill disc rotating shaft and the fixed drill disc ring, each group of fixed drill shafts is connected to one end of a group of foldable cutting drill shafts through a variable diameter overlapping hinge, and the other end of the foldable cutting drill shaft is provided with a lateral cutting cutter; the same end of the group of foldable cutting drill shafts is respectively connected to the outer end of a group of fixed drill shafts, and the group of foldable cutting drill shafts is arranged clockwise along the outer circumference of the fixed drill disc ring.

[0014] Each group of stirring blades has an inclined angle of 30 to 60 degrees at the connection with the working drill shaft, and among the two adjacent groups of stirring blades in the same horizontal section of the working drill shaft, the inclined angle of the connection with the working drill shaft of one group is upward, and the inclined angle of the connection with the working drill shaft of the other group is downward.

[0015] Each group of the plurality of stirring blades and a group of cement slurry spraying devices are located in the same horizontal section of the working drill shaft.

[0016] In summary, the variable diameter high pressure jet grouting pile has the following advantages and beneficial effects:

[0017] 1. This application proposes a design scheme for a variable diameter drill bit and a new type of spraying blade. The variable diameter drill bit can be used to adjust different diameters according to the adaptability of different bottom conditions. As a whole, it is applicable to a variety of geological, stratigraphic and construction conditions, effectively improving construction efficiency and foundation pit engineering quality.

[0018] 2. The present application is applicable to the construction of high-pressure rotary jet piles. Through the new type of shotcrete blades and the use of two slurries with different water-cement ratios for mixed shotcrete, high-pressure water is sprayed to clean the shotcrete holes while increasing the high-pressure water jet and meeting the high-precision requirements of the cement slurry water-cement ratio. This ensures that the mud ejection end will not be blocked, thus meeting the construction requirements of achieving a high degree of fusion between the cement slurry and the soil under harsh formation conditions.

[0019] 3. The present application achieves the requirement that the spraying blades are not entangled by increasing high-pressure air holes and using high-pressure air to push the cement slurry and the soil to a high degree of fusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present application is now further described in conjunction with the following drawings;

[0021] Figure 1 This is a schematic diagram of the overall structure of the variable-diameter high-pressure jet grouting pile and the integrated drilling and jetting operation proposed in this application;

[0022] Figure 2 This is a front view of the working systems below the spiral stirring wing;

[0023] Figure 3 It is a side view of each working system below the spiral stirring blade;

[0024] Figure 4 It is a top view of the working systems below the spiral stirring wing;

[0025] Figure 5 Schematic diagram of the shotcrete gear control system closing the low water-cement ratio slurry shotcrete port;

[0026] Figure 6 Schematic diagram of the shotcrete gear control system opening the low water-cement ratio slurry shotcrete port;

[0027] Figure 7 It is a schematic diagram of a variable diameter drill bit;

[0028] Figure 8 This is a schematic diagram of the large diameter expansion of the variable diameter drill bit;

[0029] Fig. 9 This is a schematic diagram of the small diameter operation of a variable diameter drill bit;

[0030] Fig.10 Schematic diagram of a variable diameter overlapping hinge.

[0031] In the above drawings, 1. high-pressure jet grouting drill; 2. slurry delivery system; 3. working drill shaft; 4. spiral stirring wing; 5. stirring blade; 6. grouting system; 7. variable diameter drill bit;

[0032] 21. Cement slurry delivery pipe; 22. Low water-cement ratio cement slurry delivery pipe; 23. High-pressure water delivery pipe; 24. High-pressure gas delivery pipe;

[0033] 61. Cement slurry spraying device; 611. Cement slurry storage chamber; 612. Cement slurry storage chamber with compartments; 613. Cement slurry spraying port; 614. Cement slurry compartment partition; 615. Cement slurry compartment flow hole; 62. Cement slurry spraying device with low water-cement ratio; 621. Cement slurry storage chamber with low water-cement ratio; 622. Cement slurry spraying port with low water-cement ratio; 63. High-pressure water jet device; 631. High-pressure water storage chamber; 632. High-pressure water jet hole; 64. High-pressure gas jet device; 641. High-pressure gas compression chamber; 642. High-pressure gas jet hole; 65. Spraying gear control system; 651. Spraying rotating gear; 652. Cement slurry spraying rotating gear with low water-cement ratio; 653. Baffle plate for cement slurry conveying pipe with low water-cement ratio; 654. Baffle control rod; 655. Cement slurry spraying connecting ring with low water-cement ratio;

[0034] 71. Bottom drilling bit; 72. Variable diameter cutting drill disc; 721. Variable diameter cutting drill disc rotating shaft; 722. Fixed drill shaft; 723. Fixed drill disc ring; 724. Variable diameter overlapping hinge; 725. Foldable cutting drill shaft; 726. Lateral cutting blade; 727. Lateral maximum trajectory; DETAILED DESCRIPTION

[0035] In order to further explain the technical means adopted by the present application to achieve the predetermined design objectives, the following preferred implementation scheme is proposed in conjunction with the accompanying drawings.

[0036] In the following description, specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] Embodiment 1, as Figures 1 to 10 As shown, the variable-diameter high-pressure rotary jet pile proposed in the present application includes a high-pressure rotary jet drill 1, which is connected to a slurry delivery system 2. A hollow working drill shaft 3 is arranged at the working end of the high-pressure rotary jet drill 1, and a variable-diameter drill bit 7 is connected to the front end of the working drill shaft 3. A group of continuously extended and distributed spiral stirring wings 4 and an array of stirring blades 5, as well as a grouting system 6 are arranged outside the working drill shaft 3.

[0038] The slurry delivery system 2 is connected to the top of the working drill shaft 3, and includes two groups of cement slurry delivery pipes 21, two groups of low water-cement ratio cement slurry delivery pipes 22, two groups of high-pressure water delivery pipes 23 and two groups of high-pressure gas delivery pipes 24, which are externally connected to the cement mixer and the high-pressure water tank equipment and extend vertically inwardly in the hollow cavity of the working drill shaft 3;

[0039] Along the vertical direction of the working drill shaft 3, the stirring blade 5 is arranged below the spiral stirring wing 4;

[0040] The spiral stirring blades 4 extend counterclockwise outside the working drill shaft 3, so as to increase the stirring and contact area between the spiral stirring blades 4 and the soil body when rotating with the working drill shaft 3, and fully stir the cement slurry.

[0041] Each group of stirring blades 5 is connected to the working drill shaft 3 at an inclined angle of 45°, and in the two adjacent groups of stirring blades 5 in the same horizontal section of the working drill shaft 3, one group is connected to the working drill shaft 3 at an inclined angle upward, and the other group is connected to the working drill shaft 3 at an inclined angle downward, so that the two adjacent groups of stirring blades 5 are staggered and distributed to achieve the effect of fully stirring the cement slurry;

[0042] The spraying system 6 comprises two groups of cement slurry spraying devices 61 respectively connected to two groups of cement slurry delivery pipes 21, two groups of low water-cement ratio cement slurry spraying devices 62 respectively connected to two groups of low water-cement ratio cement slurry delivery pipes 22, two groups of high-pressure water jetting devices 63 respectively connected to two groups of high-pressure water delivery pipes 23, and two groups of high-pressure gas jetting devices 64 respectively connected to two groups of high-pressure gas delivery pipes 24;

[0043] Two groups of cement slurry spraying devices 61 are symmetrically connected to the two sides of the outside of the working drill shaft 3. Each group of cement slurry spraying devices 61 is provided with a cement slurry storage chamber 611 and several sub-chamber cement slurry storage chambers 612. A cement slurry sub-chamber flow hole 615 for circulating cement slurry is provided between two adjacent sub-chamber cement slurry storage chambers 612. A cement slurry sub-chamber flow hole 615 for circulating cement slurry is provided. A cement slurry spraying port 613 is provided at the outer end of each of the sub-chamber cement slurry storage chambers 612. A cement slurry sub-chamber partition 614 is provided between two adjacent cement slurry spraying ports 613. Thus, the cement slurry conveying pipe 21 conveys cement to the cement slurry storage chamber 611, so that the cement slurry flows evenly along the cement slurry storage chamber 611 to the sub-chamber cement slurry storage chamber 612. Through the cement slurry sub-chamber partition 614, the cement slurry is evenly poured in sub-chambers along the cement slurry spraying port 613.

[0044] The low water-cement ratio cement slurry sprayed by the low water-cement ratio cement slurry spraying device 62 is mixed with the high-pressure water sprayed by the high-pressure water jetting device 63 to obtain the water-cement ratio cement slurry required for the pile forming ratio.

[0045] Two groups of low water-cement ratio cement slurry spraying devices 62 are symmetrically distributed on both sides of the outside of the working drill shaft 3, and each group of cement slurry spraying devices 61 and the adjacent low water-cement ratio cement slurry spraying devices 62 are at the same vertical height of the working drill shaft 3, and the angle between the two in the horizontal section of the working drill shaft 3 is 90°;

[0046] Each set of low water-cement ratio cement slurry spraying devices 62 includes a low water-cement ratio cement slurry storage chamber 621 and a low water-cement ratio cement slurry spraying port 622 which are interconnected;

[0047] Two groups of high-pressure water jet devices 63 are symmetrically distributed on both sides of the outside of the working drill shaft 3, and are both located vertically below the low water-cement ratio cement slurry spraying device 62; each group of high-pressure water jet devices 63 and the adjacent group of low water-cement ratio cement slurry spraying devices 62 are in the same vertical section of the working drill shaft 3, and the angle between each group of high-pressure water jet devices 63 and the adjacent group of cement slurry spraying devices 61 in the same horizontal section of the working drill shaft 3 is 90°;

[0048] Each set of high-pressure water jetting devices 63 includes a high-pressure water storage chamber 631 and a high-pressure water jetting hole 632 which are interconnected. The high-pressure water jetting holes 632 are distributed upward along the outer wall of the working drill shaft 3 at an angle of 15 degrees, so as to use the jetted high-pressure water to flush the low water-cement ratio cement slurry spraying port 622 and the cement slurry spraying port 613;

[0049] Two sets of high-pressure gas injection devices 64 are symmetrically distributed on both sides of the outside of the working drill shaft 3, and are both located vertically below the high-pressure water spraying device 63, and are in the same vertical section of the working drill shaft 3 as the cement slurry spraying device 61;

[0050] Each set of high-pressure gas injection devices 64 includes a high-pressure gas compression chamber 641 and a high-pressure gas injection hole 642 that are interconnected. The high-pressure gas injection holes 641 are distributed upward along the outer wall of the working drill shaft 3 at an angle of 30 degrees, so as to utilize the injected high-pressure gas to promote the fusion of cement slurry and soil, thereby achieving a higher degree of fusion;

[0051] Furthermore, a spraying gear control system 65 may be provided at the entire upper end of the spraying system 6, wherein the spraying gear control system 65 includes two groups of spraying rotating gears 651 and two groups of low water-cement ratio cement slurry spraying rotating gears 652, and the adjacent spraying rotating gears 651 and low water-cement ratio cement slurry spraying rotating gears 652 are meshed; when the spraying is working, the spraying rotating gear 651 is rotated by the driving device and drives the low water-cement ratio cement slurry spraying rotating gear 652 to rotate;

[0052] The two groups of cement slurry delivery pipes 21 pass through the vertical gaps of the two groups of shotcrete rotating gears 651 respectively, but the cement slurry delivery pipes 21 do not rotate with the shotcrete rotating gears 651;

[0053] The two groups of low water-cement ratio cement slurry delivery pipes 22 respectively pass through the vertical gaps of the two groups of low water-cement ratio cement slurry spraying rotating gears 652, but the low water-cement ratio cement slurry delivery pipes 22 do not rotate with the low water-cement ratio cement slurry spraying rotating gears 652; a low water-cement ratio cement slurry delivery pipe baffle 653 for opening or closing the low water-cement ratio cement slurry delivery pipe 22 is provided on one side of the low water-cement ratio cement slurry spraying rotating gear 652; when the low water-cement ratio cement slurry delivery pipe baffle 653 closes the low water-cement ratio cement slurry delivery pipe 22, the low water-cement ratio cement slurry cannot be sprayed out from the low water-cement ratio cement slurry spraying device 62; otherwise, it can be sprayed out;

[0054] Furthermore, one end of a baffle plate control rod 654 is connected to one side of the shotcrete rotating gear 651, and the other end of the baffle plate control rod 654 is connected to a low water-cement ratio cement slurry shotcrete connecting ring 655, and the low water-cement ratio cement slurry shotcrete connecting ring 655 is a hollow circular ring and the baffle plate control rod 654 can rotate together with the shotcrete rotating gear 651;

[0055] The bottom of the low water-cement ratio cement slurry delivery pipe shielding plate 653 is connected to the low water-cement ratio cement slurry spraying rotating gear 652 through a set of springs. When the low water-cement ratio cement slurry spraying connecting ring 655 rotates to the vertical upper side of the low water-cement ratio cement slurry delivery pipe shielding plate 653 along with the spraying rotating gear 651, the low water-cement ratio cement slurry spraying connecting ring 655 presses down the low water-cement ratio cement slurry delivery pipe shielding plate 653 due to the bending and energy storage of the spring, and drives it to move downward until the low water-cement ratio cement slurry delivery pipe shielding plate 653 no longer closes the water-cement ratio cement slurry delivery pipe 22, and the low water-cement ratio cement slurry It can be sprayed out from the low water-cement ratio cement slurry spraying device 62; then, when the spring is bent more, the low water-cement ratio cement slurry delivery pipe shielding plate 653 is misaligned with the low water-cement ratio cement slurry spraying connecting ring 655 above it due to the large bending, and the low water-cement ratio cement slurry delivery pipe shielding plate 653 is no longer subjected to the downward pressure of the low water-cement ratio cement slurry spraying connecting ring 655, the elastic potential energy of the spring is released, and the low water-cement ratio cement slurry delivery pipe shielding plate 653 is able to rebound to the initial position, thereby continuing to shield the low water-cement ratio cement slurry delivery pipe 22, and the low water-cement ratio cement slurry spraying device 62 stops spraying;

[0056] Further, each group of the stirring blades 5 and a group of cement slurry spraying devices 61 are located in the same horizontal section of the working drill shaft 3;

[0057] The variable diameter drill bit 7 is used to realize the construction of high-pressure jet grouting piles of different diameters according to different soil geological conditions. It is composed of a bottom drilling drill bit 71 and a variable diameter cutting drill disc 72. The variable diameter cutting drill disc 72 is arranged at the upper end of the bottom drilling drill bit 71.

[0058] The variable diameter cutting drill disc 72 comprises a variable diameter cutting drill disc rotating shaft 721 and a fixed drill disc ring 723. The axial ends of the variable diameter cutting drill disc rotating shaft 721 are respectively fixedly connected to the bottom drilling drill bit 71 and the vertical direction of the working drill shaft 3. The circumferential direction of the fixed drill disc ring 723 is fixedly connected to the inner wall of the bottom drilling drill bit 71. A plurality of fixed drill shafts 722 are fixedly connected in the horizontal radial direction between the variable diameter cutting drill disc rotating shaft 721 and the fixed drill disc ring 723. Each group of fixed drill shafts 722 is connected to one end of a group of foldable cutting drill shafts 725 through a variable diameter overlapping hinge 724. The other end of the foldable cutting drill shaft 725 is provided with a lateral cutting knife 726. The same end of the plurality of foldable cutting drill shafts 725 is respectively connected to the outer end of a group of fixed drill shafts 722, and the plurality of foldable cutting drill shafts 725 are arranged clockwise along the outer circumference of the fixed drill disc ring 723.

[0059] After the bottom drilling drill bit 71 is used to break and drill the rock and soil, the array of foldable cutting drill shafts 725 of the variable diameter cutting drill disc 72 is rotated counterclockwise along the outer circumference of the fixed drill disc ring 723 to open, and the lateral cutting tool 726 at its end is used to cut the rock and soil, thereby further increasing the diameter of the drill hole; moreover, the lateral cutting tool 726 can also be used to ensure that the mixing blades 5 are not entangled during pile construction.

[0060] When the variable diameter drill bit 7 rotates clockwise, all the foldable cutting drill shafts 725 are simultaneously unfolded counterclockwise through the variable diameter overlapping hinge 724. The maximum unfolding angle of the foldable cutting drill shaft 725 relative to the fixed drill shaft 722 can be 180°, so that the drilling diameter formed by the lateral cutting knife 726 is expanded to the lateral maximum trajectory 727.

[0061] When the variable diameter drill bit 7 rotates counterclockwise, all the foldable cutting drill shafts 725 can be folded through the variable diameter overlapping hinges 724; when the counterclockwise rotation speed exceeds 60r / min, the foldable cutting drill shaft 725 is completely folded back to the inner circle of the fixed drill disk ring 723, that is, it is stored in the internal space of the bottom drilling drill bit 71 and is no longer exposed. At this time, drilling only relies on the bottom drilling drill bit 71.

[0062] Based on the use of the above-mentioned variable diameter high-pressure rotary jet grouting piles, the following high-pressure rotary jet grouting construction process can be carried out and implemented:

[0063] Step (1), according to the engineering geological and hydrogeological conditions in the site, select suitable cement, and specify the composition and dosage of admixtures such as early strength agent, quick setting agent, water glass, etc.;

[0064] Step (2), using a multifunctional high-pressure jet grouting drill, drilling and grouting in one, completing drilling and grouting simultaneously, completing instrument inspection, and ensuring that all construction machines and tools are operating normally;

[0065] Step (3), leveling the site, removing movable obstacles on the ground and underground, ensuring that the construction platform is flat and solid, improving temporary facilities for construction, formulating environmental protection measures, and arranging excavated soil discharge ditches and slurry collection pits;

[0066] Step (4), measure the location of pipelines and structures around the site, set up safety signs, and formulate safety protection measures;

[0067] Step (5) Conduct technical briefings to the construction team, including the surrounding pipelines, structure locations, engineering geology and hydrogeology data within the site, and construction requirements;

[0068] Step (6), measurement and setting out: measure and set out the construction axis according to the designed construction drawings and coordinate grid points;

[0069] Step (7), determine the hole position: determine the hole position on the construction axis, assign the pile number, hole number and serial number, and measure the ground elevation of each hole opening according to the reference point;

[0070] Step (8), stirring and slurrying: preparing two slurries with different water-cement ratios, one cement slurry configured according to a suitable water-cement ratio obtained by calculation, and the other cement slurry with a low water-cement ratio calculated according to the water spraying amount of the high-pressure water hole, ensuring that a suitable cement slurry can be obtained after adding the high-pressure water spraying amount to the cement slurry with a low water-cement ratio, and continuously injecting them into two different grouting pipes;

[0071] Step (9), drilling and spraying: using a variable diameter drill bit to drill holes, and spraying at the same time, the spraying is controlled by a spraying gear control system to spray appropriate low water-cement ratio cement slurry;

[0072] Step (10), water and gas spraying: spraying high-pressure water and high-pressure gas while drilling and spraying;

[0073] Step (11), changing the drill bit diameter: when the diameter of the lower pile needs to be adjusted, stop the clockwise rotation of the variable diameter drill bit, adjust the variable diameter drill bit to rotate counterclockwise, and the rotation speed exceeds 60r / min. The foldable cutting drill shaft and the stackable cutting drill disc can be completely overlapped by rotating counterclockwise for one minute. After the overlap is completed, the foldable cutting drill shaft and the stackable cutting drill disc are locked, and the drill bit continues to rotate clockwise to drill and spray.

[0074] Step (12), swing lifting: after the drill bit has drilled to the designed depth and the grout has been sprayed to the designed depth, the drill bit is rotated counterclockwise to lift the drill bit to the ground;

[0075] Step (13), pile formation: measuring the quality of the pile formation, and inspecting various parameters such as the strength and verticality of the pile;

[0076] Step (14), cleaning completion: After the high-pressure jet grouting of each hole is completed, the grouting pump and the grouting pipeline should be cleaned in time to prevent the slurry from settling and agglomerating in the grouting pipeline due to untimely and incomplete cleaning, thereby blocking the grouting pipeline and nozzle and affecting the construction of the next hole.

[0077] As described above, similar technical solutions can be derived from the solutions given in the drawings and descriptions. However, any solution content that does not deviate from the structure of the present invention still belongs to the scope of rights of the technical solution of this application.

Claims

1. A variable diameter high pressure jet grouting pile, characterized in that: The high-pressure rotary jet drilling machine is connected to a slurry delivery system, a hollow working drill shaft is arranged at the working end of the high-pressure rotary jet drilling machine, a variable-diameter drill bit is connected to the front end of the working drill shaft, a group of continuously extending spiral stirring wings and a group of stirring blades are arranged outside the working drill shaft, and a slurry spraying system; The slurry delivery system is connected to the top of the working drill shaft, and includes at least one set of cement slurry delivery pipes, at least one set of low water-cement ratio cement slurry delivery pipes, at least one set of high-pressure water delivery pipes and at least one set of high-pressure gas delivery pipes, which are externally connected to the cement mixer and the high-pressure water tank equipment and extend vertically inwardly and are arranged in the hollow cavity of the working drill shaft; The spraying system includes a cement slurry spraying device connected to a cement slurry delivery pipe, a low water-cement ratio cement slurry spraying device connected to a low water-cement ratio cement slurry delivery pipe, a high-pressure water jetting device connected to a high-pressure water delivery pipe, and a high-pressure gas jetting device connected to a high-pressure gas delivery pipe.

2. The variable diameter high pressure jet grouting pile according to claim 1 is characterized in that: An array of cement slurry spraying devices is symmetrically connected to both sides of the outside of the working drill shaft. Each group of cement slurry spraying devices is provided with a cement slurry storage chamber and several sub-compartment cement slurry storage chambers. A cement slurry sub-compartment circulation hole for circulating cement slurry is provided between two adjacent sub-compartment cement slurry storage chambers. At least one cement slurry spraying port is provided at the outer end of each sub-compartment cement slurry storage chamber, and a cement slurry sub-compartment partition is provided between two adjacent cement slurry spraying ports.

3. The variable diameter high pressure jet grouting pile according to claim 1 is characterized in that: The plurality of low water-cement ratio cement slurry spraying devices are symmetrically distributed on both sides of the outside of the working drill shaft, each group of cement slurry spraying devices and the adjacent low water-cement ratio cement slurry spraying devices are at the same vertical height of the working drill shaft, and the angle between the two in the horizontal section of the working drill shaft is 90°; each group of low water-cement ratio cement slurry spraying devices includes a low water-cement ratio cement slurry storage chamber and a low water-cement ratio cement slurry spraying port that are interconnected.

4. The variable diameter high pressure jet grouting pile according to claim 1 is characterized in that: The plurality of high-pressure water jet devices are symmetrically distributed on both sides of the outside of the working drill shaft and are all located vertically below the low water-cement ratio cement slurry spraying device; each group of high-pressure water jet devices and an adjacent group of low water-cement ratio cement slurry spraying devices are in the same vertical section of the working drill shaft, and the angle between each group of high-pressure water jet devices and an adjacent group of cement slurry spraying devices in the same horizontal section of the working drill shaft is 90°; each group of high-pressure water jet devices includes a high-pressure water storage chamber and high-pressure water spray holes that are interconnected, and the high-pressure water spray holes are distributed upward along the outer wall of the working drill shaft at an angle of 10 to 25°.

5. The variable diameter high pressure jet grouting pile according to claim 1 is characterized in that: The plurality of high-pressure gas injection devices are symmetrically distributed on both sides of the outside of the working drill shaft, and are all located vertically below the high-pressure water spraying device, and are in the same vertical section of the working drill shaft as the cement slurry spraying device; each group of high-pressure gas injection devices includes a high-pressure gas compression chamber and a high-pressure gas injection hole that are interconnected, and the high-pressure gas injection holes are distributed upward along the outer wall of the working drill shaft at an angle of 15 to 45 degrees.

6. The variable diameter high pressure jet grouting pile according to claim 1 is characterized in that: A shotcrete gear control system is arranged at the overall upper end of the shotcrete system, wherein the shotcrete gear control system comprises two groups of shotcrete rotating gears and two groups of low water-cement ratio cement slurry shotcrete rotating gears, and adjacent shotcrete rotating gears and low water-cement ratio cement slurry shotcrete rotating gears are meshed; Two groups of cement slurry delivery pipes pass through the vertical gaps of the two groups of shotcrete rotating gears respectively, but the cement slurry delivery pipes do not rotate with the shotcrete rotating gears; Two groups of low water-cement ratio cement slurry delivery pipes respectively pass through the vertical gaps of the two groups of low water-cement ratio cement slurry shotcrete rotating gears, but the low water-cement ratio cement slurry delivery pipes do not rotate with the low water-cement ratio cement slurry shotcrete rotating gears; A low water-cement ratio cement slurry delivery pipe shielding plate for opening or closing the low water-cement ratio cement slurry delivery pipe is arranged on one side of the low water-cement ratio cement slurry spraying rotating gear.

7. The variable diameter high pressure jet grouting pile according to claim 6 is characterized by: One end of a baffle control rod is connected to one side of the shotcrete rotating gear, and the other end of the baffle control rod is connected to a low water-cement ratio cement slurry shotcrete connecting ring. The low water-cement ratio cement slurry shotcrete connecting ring is a hollow ring and the baffle control rod can rotate with the shotcrete rotating gear; the bottom of the low water-cement ratio cement slurry conveying pipe baffle is connected to the low water-cement ratio cement slurry shotcrete rotating gear through a group of springs.

8. The variable diameter high pressure jet grouting pile according to claim 1 is characterized by: The variable diameter drill bit is composed of a bottom drilling drill bit and a variable diameter cutting drill disc, and the variable diameter cutting drill disc is arranged at the upper end of the bottom drilling drill bit; The variable diameter cutting drill disc comprises a variable diameter cutting drill disc rotating shaft and a fixed drill disc ring, the axial ends of the variable diameter cutting drill disc rotating shaft are respectively fixedly connected to the bottom drilling drill bit and the vertical direction of the working drill shaft, the circumferential direction of the fixed drill disc ring is fixedly connected to the inner wall of the bottom drilling drill bit, and a plurality of fixed drill shafts are fixedly connected in the horizontal radial direction between the variable diameter cutting drill disc rotating shaft and the fixed drill disc ring, each group of fixed drill shafts is connected to one end of a group of foldable cutting drill shafts through a variable diameter overlapping hinge, and a lateral cutting cutter is arranged at the other end of the foldable cutting drill shaft; the same end of the plurality of foldable cutting drill shafts is respectively connected to the outer end of a group of fixed drill shafts, and the plurality of foldable cutting drill shafts are arranged clockwise along the outer circumference of the fixed drill disc ring.

9. The variable diameter high pressure jet grouting pile according to claim 1, characterized in that: Each group of stirring blades has an inclined angle of 30 to 60 degrees at the connection with the working drill shaft, and among the two adjacent groups of stirring blades in the same horizontal section of the working drill shaft, the inclined angle of the connection with the working drill shaft of one group is upward, and the inclined angle of the connection with the working drill shaft of the other group is downward.

10. The variable diameter high pressure jet grouting pile according to claim 1 or 5, characterized in that: Each group of the plurality of stirring blades and a group of cement slurry spraying devices are located in the same horizontal section of the working drill shaft.

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