High-pressure-injection-grouting pedestal pile, high-pressure-injection-grouting pedestal pile construction method and high-pressure-injection-grouting pedestal pile construction equipment

Abstract

The invention relates to a high-pressure-jet-grouting pedestal pile and a high-pressure-jet-grouting pedestal pile construction method and equipment, and the high-pressure-jet-grouting pedestal pile comprises a pile body which is formed in a pile hole, and a pedestal pit with the diameter larger than that of the pile body is formed in an undisturbed soil body in the lower portion of the pile body; the expanding body is formed by solidifying the formed concrete which is fed into the expanded pit through post-pressure and is in a sphere-like shape; the lower surrounding body is formed in the mode that cement paste which is firstly pressed and fed into the expanded pit is extruded by the formed concrete which is later pressed and fed to the periphery and then solidified, and the solidified lower surrounding body wraps the peripheral side of the expanded body; the upper surrounding body is formed in the mode that cement paste which is firstly pressed into the expanded pit is solidified after being overflowed into a gap between the pile body and the pile hole by the forming concrete which is pressed later, and the upper surrounding body surrounds the peripheral side of the bottom end of the pile body. According to the anti-explosion pile, the surrounding soil body is basically not disturbed, the noise is low, the anti-explosion pile can be achieved, the upper surrounding body and the lower surrounding body which are integrally solidified and formed wrap and protect the joint part between the pile body and the expansion body, and the anti-shearing capacity of the joint part of the pile body and the expansion body can be greatly improved.

Description

Technical Field

[0001] The present application relates to the technical field of pile foundation construction, and in particular to a high-pressure jetting grouting and bottom-enlarged pile, a high-pressure jetting grouting and bottom-enlarged pile construction method and construction equipment thereof. Background Art

[0002] The expanded base pile is a special type of pile foundation that increases the pile's bearing capacity by creating an expanded head at the bottom of the pile. This design allows the pile to provide greater support when subjected to vertical and horizontal loads; the pile body can be a prefabricated pipe pile or a cast-in-place pile. At present, the expanded head at the bottom of the expanded base pile is mainly formed by compacting the filler with a heavy hammer, which can provide the pile body with better bearing performance even in some soft soil layers.

[0003] As the technical advantages of expanded base piles continue to emerge, expanded base piles have gradually been applied to various pile foundation projects. However, expanded base piles that form an enlarged head by ramming filler have some natural disadvantages. For example, the surrounding soil is greatly disturbed during the ramming process with a heavy hammer. If the pile positions are closely arranged or there are existing buildings adjacent to them, it is easy to cause interference to the pile foundations or existing buildings at adjacent pile positions; and the noise during the ramming process is not easy to control. If prefabricated pipe piles are used as the pile body, there is a risk of the prefabricated pipe piles being rammed to pieces during the ramming process of the filler with a heavy hammer. In addition, the connection between the pile body and the enlarged head of the expanded base pile is weak, making it difficult to bear large horizontal loads.

[0004] Therefore, the construction process of using a heavy hammer to ram the filling material to form an enlarged head still has certain limitations, which to a certain extent restricts the development and advancement of the base expansion pile technology. For this reason, it is necessary to improve a new base expansion pile type and construction method to solve the above-mentioned shortcomings and facilitate the promotion and application of the base expansion pile technology. Summary of the invention

[0005] In order to improve the problems of soil disturbance, loud noise, easy pile explosion and low horizontal load bearing capacity of the enlarged head and pile body caused by heavy hammer tamping when the enlarged head of the enlarged base pile is formed, the present application provides a high-pressure jet grouting enlarged base pile, a high-pressure jet grouting enlarged base pile construction method and construction equipment.

[0006] The first aspect of the present application provides a high pressure jetting grouting pile that adopts the following technical solution: A high pressure jetting grouting pile, comprising: The pile body is formed in the pile hole, and the lower part of the pile body is formed with an expanded bottom pit with a diameter larger than the diameter of the pile body in the original soil; The expanded body is formed by curing the molded concrete that is subsequently pressed into the bottom expansion pit and is spherical in shape; The lower enclosure is formed by the cement slurry first pressed into the bottom expansion pit being squeezed around by the molded concrete that is later pressed and then solidified, and the solidified lower enclosure is wrapped around the periphery of the expansion body; An upper enclosure, formed by the cement slurry first pressed into the bottom expansion pit and then solidified by the formed concrete that is subsequently pressed into the gap between the pile body and the pile hole, and surrounding the circumference of the bottom end of the pile body; and The reinforcement body is formed by mixing cement slurry and loose soil that are first pressed into the bottom expansion pit to form cement soil, and then the molded concrete that is pressed later penetrates into the original soil body outside the bottom expansion pit and solidifies, and it surrounds the circumference of the lower enclosure.

[0007] Furthermore, an anti-pullout member is connected between the enlarged body and the pile body, and one end of the anti-pullout member is buried in the pile body and the other end is buried in the enlarged body.

[0008] The second aspect of the present application provides a high pressure jetting grouting and enlarging pile construction method using the following technical solution: A high pressure jetting grouting and enlarged pile construction method comprises the following steps: S1. Equipment enters the site and the pile position is marked according to the construction requirements; S2. Take the corresponding fixed pile cylinder according to the designed pile diameter and press it down to the bearing layer at the pile position; S3. Remove the soil in the hollow portion of the pile cylinder; S4. The bottom expansion pit is formed by jetting cutting or diameter expansion cutting in the original soil at the bottom of the pile cylinder; if the jetting cutting method is adopted, the injected cement slurry is mixed with the cut loose soil to form cement soil; if the diameter expansion cutting method is adopted, after the bottom expansion pit is formed, cement slurry is injected into the bottom expansion pit and mixed with the cut loose soil to form cement soil; S5. Pressurize the molded concrete into the bottom expansion pit and limit the molded concrete from rising in the hollow portion of the pile cylinder, so that the cement soil in the bottom expansion pit is squeezed into the original soil around the bottom expansion pit and into the gap between the pile cylinder and the pile hole; S6. pouring concrete into the hollow part of the pile cylinder to form a pile body.

[0009] Furthermore, after the molded concrete and cement soil in the bottom expansion pit in step S5 are solidified, the solidified molded concrete forms an expanded body, the cement soil in the bottom expansion pit is solidified to form a lower enclosure wrapped outside the expanded body, the cement soil in the gap between the pile cylinder and the pile hole is solidified to form an upper enclosure wrapped around the bottom end of the rail pile cylinder and connected to the lower enclosure, and the cement soil on the pit wall of the bottom expansion pit that penetrates into the original soil body is solidified to form a reinforcement body wrapped around the periphery of the lower enclosure.

[0010] Furthermore, if anti-pullout piles are constructed, in step S6, before the formed concrete in the bottom-enlarged pit begins to set, an anti-pullout member is inserted into the bottom-enlarged pit, and the upper portion of the anti-pullout member extends into the hollow portion of the pile cylinder.

[0011] Furthermore, if cast-in-place piles are constructed, the pile cylinder in step S2 is set to be a steel pipe with an inner diameter equal to the designed pile diameter; If prefabricated piles are used, the pile cylinder in step S2 is set as a prestressed pipe pile with an outer diameter equal to the designed pile diameter.

[0012] Furthermore, the diameter of the bottom expansion pit formed in step S4 is not less than 1.5 times the designed pile diameter and the depth is not less than 500 mm.

[0013] Furthermore, in step S4, cement slurry is sprayed into the original soil at the bottom of the pile cylinder by a high-pressure nozzle, and the lower the compression modulus of the original soil at the bottom of the pile cylinder is, the smaller the spraying pressure is.

[0014] The third aspect of the present application provides a high-pressure jetting grouting and expansion pile construction equipment adopts the following technical solution: A high-pressure jetting grouting and bottom-enlarging pile construction equipment, used to implement the above-mentioned high-pressure jetting grouting and bottom-enlarging pile construction method, comprising: a main shaft, the interior of which is penetrated to form a grouting channel; A spiral conveying blade is spirally wound on the outer peripheral wall of the main shaft and extends along the length direction of the main shaft; A drill bit, which is mounted at the bottom end of the main shaft and is used to drill into the soil or rock layer and stir the soil; A plurality of nozzles are provided and installed at the bottom end of the main shaft; A slurry delivery pipe is fixedly connected to the outer wall of the main shaft along the length direction of the main shaft, and the slurry delivery pipe is connected to the plurality of nozzles; A sealing plate, movably mounted on the bottom end of the main shaft and used to seal the grouting channel; and The rotary lifting machine is used to drive the main shaft to rotate forward, reverse or lift.

[0015] Furthermore, when executing step S3, the rotary lifting machinery is controlled to drive the main shaft to rotate forward and continuously insert the main shaft into the hollow portion of the pile cylinder, the soil is crushed by means of the drill bit, and the crushed soil is output upward by the spiral conveying blades.

[0016] Furthermore, when executing step S4, the rotary lifting machinery is controlled to move the main shaft downward to extend at least 500 mm from the lower end of the pile cylinder, the main shaft is kept in a rotating state, and cement slurry of a set pressure is delivered to the slurry pipe, so that the cement slurry is sprayed from the plurality of nozzles to perform jet cutting on the surrounding soil; at the same time, the drill bit follows the rotation to stir the cut soil and cement slurry to form cement soil.

[0017] Furthermore, when executing step S5, the rotary lifting machinery is controlled to drive the main shaft to reverse, the sealing of the bottom end of the main shaft by the sealing plate is released, and the molded concrete is poured into the grouting channel of the main shaft, and the downward thrust of the spiral conveying blade when rotating in the opposite direction is used to force the molded concrete to squeeze the cement soil, so that the cement soil is squeezed toward the surrounding side and into the gap between the fixed pile tube and the pile hole.

[0018] Furthermore, the sealing plate is movably connected to the bottom end of the main shaft. When the main shaft moves downward against the soil, the sealing plate blocks the grouting channel at the bottom end of the main shaft; when the main shaft is lifted up, the sealing plate is separated from the grouting channel at the bottom end of the main shaft.

[0019] Furthermore, the drill bit comprises: A base, detachably mounted on the bottom end of the spindle; A drilling head, detachably mounted on a side of the base away from the main shaft, for drilling in soil or rock; The stirring head is detachably mounted on the side wall of the base and is used for stirring the plate in the crushed soil / rock mass. The stirring head is provided in plurality and surrounds the periphery of the drilling head.

[0020] Furthermore, the drill bit comprises: A base, detachably mounted on the bottom end of the spindle; A movable plate is arranged below the base, and a drilling head is detachably mounted on a side of the movable plate away from the base; An expansion disk, whose upper arm is hinged to the side of the base and whose lower arm is hinged to the side of the movable plate, and a plurality of the expansion disks are arranged at equal intervals around the base; and A stabilizing column has one end fixedly connected to the movable plate and the other end extending into the grouting channel.

[0021] In summary, the beneficial technical effects of this application are: 1. The enlarged head of the high-pressure jetting pile of the present application is composed of an inner enlarged body and an outer lower surrounding body. There is no need to tamp the soil with a heavy hammer, and the disturbance to the surrounding soil is minimal. The construction noise is also extremely low. It is suitable for piles with high requirements for construction noise control or where the piles are densely located or close to the original construction piles. 2. Even if the high-pressure jetting and grouting piles of the present application are prefabricated piles, the prestressed pipe piles can also serve as good slurry delivery pipelines, which can facilitate the pressurized pumping of cement slurry and concrete. At the same time, during the slurry delivery process, the bottom of the prestressed pipe pile is temporarily sealed or pressurized, so that the molded concrete that is subsequently pressed can squeeze the cement slurry at a higher pressure to penetrate into the gap between the pile body and the pile hole, thereby promoting the formation of the upper enclosure. Therefore, there is no possibility of explosion of the prestressed pipe piles; 3. The solidified upper and lower enclosures in the high-pressure jetting and expanded bottom pile of the present application are formed as a whole by expanding the cement soil in the expansion pit, and can form a sheath surrounding the pile body and the expansion body, which can not only reduce the corrosion of the steel bars in the high-pressure jetting and expanded bottom pile after forming by groundwater during the later use, but also improve the local structural strength of the expansion body and the pile body; and the sheath composed of the upper and lower enclosures can well wrap the joint between the pile body and the expansion body, which can fully ensure the structural strength between the joints of the two, and improve the shear resistance at the joints of the two, thereby significantly improving the horizontal load performance of the high-pressure jetting and expanded bottom pile; 4. The lower enclosure, upper enclosure and reinforcement of the present application are all formed by mixing and solidifying high-pressure sprayed cement slurry with the loose soil when the bottom pit is expanded, which can effectively solve the problem in the prior art that after the pile foundation is formed, there is often sediment at the bottom of the pile hole that cannot be completely cleaned, which affects the bearing performance of the pile foundation after forming; 5. During the construction of the high-pressure jetting and bottom-expanding piles of the present application, the pile barrel is directly pressed down to the bearing layer without pre-drilling, which simplifies the construction steps and greatly improves the construction efficiency. In addition, the pile barrel is tightly wrapped by the soil layer, which can also improve the fit between the bottom of the pile body and the bearing layer elevation after forming. It is not easy to sink during the construction process and is easier to construct according to the design requirements. When taking soil from the hollow part, it can be extended all the way to the bottom of the pile barrel and a bottom-expanding pit can be formed at the bottom of the pile barrel. Even if the construction is carried out in a stratum rich in groundwater, it will not cause significant interference to the subsequent construction steps. Compared with the operation of sealing the bottom pipe piles and then pressing the piles when encountering groundwater in conventional technology, the construction method of the present application is simpler and more economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a structural cross-sectional view of the high-pressure jetting grouting and enlarged bottom pile of the present application when the pile body is a prefabricated pile; Figure 2 This is a structural cross-sectional view of the high-pressure jetting pile of the present application when the pile body is a cast-in-place pile; Figure 3 This is a structural cross-sectional view of the high-pressure jetting grouting and expansion pile of the present application when it is an anti-pullout pile; Figure 4 This is a construction flow chart of the high pressure jetting grouting and enlarged pile of the present application; Figure 5It is a schematic diagram of the overall structure of the high-pressure jetting grouting and enlarging pile construction equipment of the present application; Figure 6 It is a structural cross-sectional view of the fourth embodiment of the high-pressure jetting grouting and enlarging pile construction equipment of the present application; Figure 7 This is a structural cross-sectional view of Embodiment 5 of the high-pressure jetting grouting and enlarging pile construction equipment of the present application; Figure 8 It is a structural cross-sectional view of Example 6 of the high-pressure jet grouting and expansion pile construction equipment of the present application.

[0023] Description of reference numerals: 1. Pile body; 11. Pile cylinder; 111. Steel pipe; 112. Prestressed pipe pile; 2. Enlarge the body; 31. Lower enclosure; 32. Upper enclosure; 4. Reinforcement; 5. Anti-pullout parts; 6. Original soil; 61. Pile hole; 62. Expanded pit; 7. Main shaft; 71. Grouting channel; 72. Spiral conveying blade; 73. Closing plate; 731. Sliding rod; 732. Anti-slip head; 733. Guide cone; 74. Positioning sleeve; 8. Drill bit; 81. Base; 82. Drilling head; 83. Mixing head; 84. Movable plate; 841. Through hole; 85. Expanding plate; 86. Stabilizing column; 861. Slurry delivery channel; 87. Spring; 91. Nozzle; 92. Slurry delivery pipe. DETAILED DESCRIPTION

[0024] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application. Embodiment 1:

[0025] The present application embodiment discloses a high pressure jetting grouting pile. Figure 1 and Figure 2 , which includes: The pile body 1 is formed in the pile hole 61, and the lower part of the pile body 1 is formed with an expanded bottom pit 62 with a diameter larger than the diameter of the pile body 1 in the original soil 6; and the pile body 1 can be a cast-in-place pile body 1 or a prefabricated pile body 1, for example, formed by pouring concrete in the hollow part of the prestressed pipe pile 112.

[0026] The enlarged body 2 is formed by curing the molded concrete that is pressed into the bottom expansion pit 62 and is spherical in shape. Specifically, the molded concrete can be selected with different grades of concrete according to the properties of the bearing layer soil.

[0027] The lower enclosure 31 is formed by cement slurry first pressed into the bottom expansion pit 62 and then squeezed toward the surrounding by the molded concrete that is pressed later and then solidified. The solidified lower enclosure 31 is wrapped around the two sides of the expansion body.

[0028] The upper enclosure 32 is formed by the cement slurry first pressed into the bottom expansion pit 62 and then solidified by the molded concrete that is later pressed into the gap between the pile body 1 and the pile hole 61. It surrounds the bottom of the pile body 1 and is specifically in the shape of a cone that is small at the top and large at the bottom. The upper enclosure 32 and the lower enclosure 31 are solidified as a cement-soil mixture of cement slurry and the loose soil in the bottom expansion pit 62 when the pit is formed. The two are combined into a sheath that is sleeved on the close ends of the expansion body 2 and the pile body 1 and the junction between the two. And The reinforcement body 4 is formed by mixing cement slurry with loose soil which is first pressed into the bottom expansion pit 62 to form cement soil, and then the molded concrete which is pressed later penetrates into the original soil body 6 outside the bottom expansion pit 62 and solidifies. It surrounds the side of the lower enclosure 31.

[0029] Therefore, compared with the enlarged head formed by compacting the filling material in the conventional enlarged bottom pile, the enlarged head of the high-pressure jetting enlarged bottom pile of the present application is composed of the enlarged body 2 in the core area, the lower enclosure 31 of the outer layer, and the reinforcement body 4 intruding into the original soil 6. On the one hand, this high-pressure jetting enlarged bottom pile does not need to tamp the soil with a heavy hammer, and the disturbance to the surrounding soil is extremely small, and the construction noise is also extremely low. It is suitable for piles with high requirements for construction noise control or piles with dense pile positions or close to the original construction. On the other hand, even if prefabricated piles are constructed, the prestressed pipe pile 112 can also be used as a good slurry delivery pipe 92, which can facilitate the pressurized pumping of cement slurry and concrete. At the same time, during the slurry delivery process, the bottom end of the prestressed pipe pile 112 is temporarily closed or pressurized, and the molded concrete that is pressed later can also squeeze the mixture of cement slurry and virtual soil with a higher pressure to make it penetrate into the gap between the pile body 1 and the pile hole 61, promoting the formation of the upper enclosure 32, so there is no possibility of pile explosion in the prestressed pipe pile 112.

[0030] On the third aspect, the solidified upper enclosure 32 and the lower enclosure 31 are integrally formed by expanding the cement soil in the bottom expansion pit 62, and can form a sheath surrounding the pile body 1 and the enlarged body 2. This can not only reduce the rust erosion of the steel bars in the high-pressure jetting and bottom expansion pile after forming by groundwater during later use, but also improve the local structural strength of the enlarged body 2 and the pile body 1; and the sheath composed of the upper enclosure 32 and the lower enclosure 31 can well wrap the joint between the pile body 1 and the enlarged body 2, which can fully ensure the structural strength between the joints, and improve the shear resistance at the joints, thereby significantly improving the horizontal load performance of the high-pressure jetting and bottom expansion pile.

[0031] Fourthly, since the lower enclosure 31, the upper enclosure 32 and the reinforcement body 4 are all formed by mixing and solidifying high-pressure sprayed cement slurry with the loose soil when the bottom expansion pit 62 is formed, it can effectively solve the problem in the prior art that after the pile foundation is formed, there is often sediment at the bottom of the pile hole 61 that cannot be thoroughly cleaned, which affects the bearing performance of the single pile of the pile foundation after formation.

[0032] Moreover, during actual construction, if the expanded bottom pit 62 is formed by rotary jet cutting, when the cement slurry is sprayed to form the expanded bottom pit 62, the hollow and cracked parts in the original soil 6 around the expanded bottom pit 62 are cut off under the impact of the high-pressure cement slurry, so that the pit wall of the expanded bottom pit 62 can be basically a hardened soil layer or rock layer; and then when the formed concrete is also pressed into the expanded bottom pit 62 at a certain pressure, a part of the cement soil in the expanded bottom pit 62 will penetrate into these hollows or cracks in the original soil 6 on the side of the expanded bottom pit 62. After this part of the cement soil is solidified and hardened, a reinforcement body 4 is formed surrounding the outer periphery of the expanded bottom pit 62, which not only strengthens the compactness of the original soil 6 around the expanded head after forming, but also can significantly enhance the bonding tightness between the expanded head after forming and the surrounding original soil 6, thereby also improving the stability and single pile bearing performance of the high-pressure jetting expanded bottom pile of the present application. Embodiment 2:

[0033] The present application embodiment discloses a high pressure jetting grouting and enlarging pile, referring to Figure 3 , which is different from the first embodiment in that: When constructing pull-out piles, a pull-out member 5 can be further connected between the enlarged body 2 and the pile body 1, with one end of the pull-out member 5 buried in the pile body 1 and the other end buried in the enlarged body 2; the pull-out member 5 can specifically be a pull-out steel cage or pull-out bars or any other rod-shaped object with an outward expansion portion in the enlarged body 2.

[0034] Therefore, with the help of the setting of the anti-pullout member 5, the connection strength between the pile body 1 and the enlarged body 2 can be further strengthened, and the anti-pullout performance of the high-pressure injection grouting and enlarged bottom pile of the present application can be improved; moreover, since the enlarged body 2 is cast by formed concrete, it is simpler to insert the anti-pullout member 5 into the enlarged head. It only needs to be inserted before the enlarged head begins to set. Compared with inserting the anti-pullout member 5 into the enlarged head formed by tamping and compacting the filling material, it is more convenient and can greatly improve the construction efficiency. Embodiment three:

[0035] The present application discloses a high pressure jetting grouting and enlarging pile construction method, referring to Figure 4 , which comprises the following steps: S1. Equipment enters the site and pile positions are marked according to construction requirements.

[0036] S2. Take the corresponding pile cylinder 11 according to the designed pile diameter, and press it down to the bearing layer at the pile position; specifically, if a cast-in-place pile is constructed, the pile cylinder 11 is set as a steel pipe 111 with an inner diameter equal to the designed pile diameter; if a prefabricated pile is constructed, the pile cylinder 11 is set as a prestressed pipe pile 112 with an outer diameter equal to the designed pile diameter; and when pressing the pile cylinder 11 down to the bearing layer, static pressure, vibration hammer, spinning and the like can be used.

[0037] S3. The soil in the hollow part of the pile cylinder 11 is taken out, specifically, the soil in the pile cylinder 11 is taken out by spiral to form an operation channel; and the spiral soil taking form is not limited to the conventional auger or long spiral method.

[0038] S4. The original soil 6 at the bottom of the pile barrel 11 is cut by jetting or expanded diameter cutting to form an expanded bottom pit 62; if the jetting cutting method is adopted, the injected cement slurry is mixed with the cut loose soil to form cement soil, which is accumulated in the expanded bottom pit 62; if the expanded diameter cutting method is adopted, after the expanded bottom pit 62 is formed, cement slurry is injected into the expanded bottom pit 62 and mixed with the cut loose soil to form cement soil, which is accumulated in the expanded bottom pit 62. Wherein, when the jetting cutting method is adopted, the cement slurry is sprayed by a high-pressure nozzle into the original soil 6 at the bottom of the pile barrel 11 in a rotary manner. The lower the compression modulus of the original soil 6 at the bottom of the pile barrel 11, the smaller the spraying pressure; and the diameter of the expanded bottom pit 62 is not less than 1.5 times the designed pile diameter, and the depth is not less than 500 mm. The lower the compression modulus of the original soil 6 at the bottom of the pile barrel 11, the greater the depth of the expanded bottom pit 62.

[0039] S5. Pressurize the molded concrete into the bottom expansion pit 62, and limit the molded concrete from surging in the hollow part of the pile cylinder 11, so that the cement soil in the bottom expansion pit 62 is squeezed into the original soil 6 on the side of the bottom expansion pit 62 and into the gap between the pile cylinder 11 and the pile hole 61. Thus, when the molded concrete and cement soil in the bottom expansion pit 62 are solidified, the solidified molded concrete forms a spherical enlarged body 2, the cement soil in the bottom expansion pit 62 is solidified to form a lower enclosure 31 wrapped around the outside of the enlarged body 2, the cement soil in the gap between the pile body 1 and the pile hole 61 is solidified to form an upper enclosure 32 that wraps around the bottom of the pile cylinder 11 and connects to the lower enclosure 31, and the cement soil on the pit wall of the bottom expansion pit 62 that penetrates into the original soil is solidified to form a reinforcement body 4 wrapped around the outer periphery of the lower enclosure 31.

[0040] S6. Pour concrete into the hollow part of the pile cylinder 11 to form the pile body 1; and when constructing precast piles, if the length of the pile body 1 is greater than 10m, it is not necessary to pour concrete throughout the hollow part of the prestressed pipe pile 112.

[0041] Therefore, by directly pressing the pile barrel 11 down to the bearing layer, there is no need to drill holes in advance, which simplifies the construction steps and greatly improves the construction efficiency. Moreover, the pile barrel 11 is tightly wrapped by the soil layer, which can also improve the fit between the bottom of the pile body 1 and the bearing layer elevation after forming, and is not easy to settle during the construction process, and it is easier to accurately form piles in the designed bearing layer according to the design requirements. And when taking soil from the hollow part of the pile barrel 11, it can be extended all the way to the bottom of the pile barrel 11, and the bottom expansion pit 62 can be formed at the bottom of the pile barrel 11. Even if the construction is carried out in a stratum rich in groundwater, it will not cause significant interference to the subsequent construction steps. Compared with the operation of sealing the bottom pipe piles and then pressing the piles in the conventional technology when encountering groundwater, the construction method of this application is simpler and more economical.

[0042] In the process of forming the bottom expansion pit 62, if the rotary jet cutting method is adopted, the soil at the bearing layer can be effectively cut by means of the cement slurry with high pressure rotary jet, so as to form the bottom expansion pit 62 with a diameter much larger than the designed pile diameter; at the same time, the probability of pipe blockage is low during the high pressure pumping of the cement slurry, and the cement slurry after cutting the soil can also be mixed with the cut loose soil to form cement soil, which can completely solve the hidden dangers caused by the pile bottom sediment; and this cement soil has good fluidity and viscosity, which is convenient for the concrete to expand and squeeze the cement soil when the concrete is poured under pressure. Therefore, in the process of pressurized pouring of concrete, by limiting the upwelling of the concrete in the hollow part of the pile barrel 11, the concrete can be filled as fully as possible under the pile barrel 11, and the cement soil can be squeezed to flow to the circumference and the upper side, so as to ensure that the expanded body 2 after forming has a sufficiently large bearing area.

[0043] Moreover, the upper surrounding body 32 and the lower surrounding body 31 thus constructed are integrally formed by expanding the cement soil in the bottom expansion pit 62, and can form a sheath surrounding the outer periphery of the formed pile body 1 and the enlarged body 2, which can not only reduce the rust erosion of the steel bars in the high-pressure jetting and bottom expansion pile by groundwater during later use, extend the service life of the pile foundation, but also improve the local structural strength of the enlarged body 2 and the pile body 1; and the sheath composed of the upper surrounding body 32 and the lower surrounding body 31 can well wrap the joint between the pile body 1 and the enlarged body 2 after formation, which can fully ensure the structural strength between the joints of the two, and improve the shear resistance at the joints of the two, thereby significantly improving the horizontal load performance of the high-pressure jetting and bottom expansion pile.

[0044] Similarly, in another feasible embodiment, if anti-pullout piles are constructed, in step S6, before the formed concrete in the expanded bottom pit 62 begins to set, an anti-pullout member 5 is inserted into the expanded bottom pit 62, and the upper part of the anti-pullout member 5 extends into the hollow part of the pile cylinder 11. The anti-pullout member 5 can specifically be an anti-pullout steel cage or anti-pullout bars or any other rod-shaped object with an outward expansion portion in the enlarged body 2.

[0045] Furthermore, during the specific construction, after the shaping concrete in the bottom expansion pit 62 is poured, the anti-pullout member 5 can be inserted into the hollow portion of the pile cylinder 11; or, after the shaping concrete in the bottom expansion pit 62 is poured, the concrete of the pile body 1 can be continuously poured to maintain sufficient downward pressure of the shaping concrete in the bottom expansion pit 62 to maintain the forming of the upper enclosure 32, and the anti-pullout member 5 can be inserted after the pouring of the pile body 1 is completed, which can also simplify the construction steps and improve the construction efficiency. Therefore, the latter is selected in this embodiment. Embodiment 4:

[0046] The present application embodiment discloses a high pressure jetting grouting and enlarging pile construction equipment, which is used to execute the high pressure jetting grouting and enlarging pile construction method as described above, referring to Figure 5 and Figure 6 , which includes: The main shaft 7 has a grouting passage 71 formed therein; The spiral conveying blade 72 is spirally wound on the outer peripheral wall of the main shaft 7 and is extended along the length direction of the main shaft 7. In the specific configuration, the outer diameter of the spiral conveying blade 72 is adapted to the inner diameter of the pile cylinder 11 to ensure a good conveying effect; A drill bit 8 is mounted at the bottom end of the main shaft 7 and is used to drill into the soil or rock layer and stir the soil; There are several nozzles 91 installed at the bottom of the main shaft 7. Specifically, in order to ensure the symmetry of cement slurry jet cutting, multiple nozzles 91 are arranged in a circular array on the periphery of the main shaft 7; The slurry delivery pipe 92 is fixedly connected to the outer wall of the main shaft 7 along the length direction of the main shaft 7. The slurry delivery pipe 92 is connected to the plurality of nozzles 91. Specifically, one slurry delivery pipe 92 may be provided, or two or more slurry delivery pipes may be provided. A sealing plate 73 is movably mounted on the bottom end of the main shaft 7 and is used to seal the grouting channel 71; and The rotary lifting mechanism is used to drive the main shaft 7 to rotate forward, reverse or lift.

[0047] And when the above-mentioned construction method is specifically implemented, the operation can be performed manually according to the construction steps, or a preset program can be set and the operation can be automatically performed by construction equipment. If the construction equipment is used for automatic execution, the rotary lifting machinery is connected to a microcomputer, and the built-in program of the microcomputer controls the rotary lifting machinery to perform the corresponding steps.

[0048] During specific execution, for example, when executing step S3, the rotary lifting machinery is controlled to drive the main shaft 7 to rotate forward and continue to insert the main shaft 7 into the hollow part of the pile cylinder 11, the soil is crushed by the drill bit 8, and the crushed soil is output upward by the spiral conveying blade 72.

[0049] When executing step S4, the rotary lifting machinery is controlled to move the main shaft 7 downward to extend at least 500 mm from the lower end of the pile cylinder 11, and the main shaft 7 is kept rotating. Cement slurry of a set pressure is delivered to the slurry delivery pipe 92, so that the cement slurry is sprayed out from a plurality of nozzles 91 to perform rotary jet cutting on the surrounding soil. At the same time, the drill bit 8 stirs the cut loose soil and cement slurry as it rotates to form cement soil.

[0050] When executing step S5, the rotary lifting machinery is controlled to drive the main shaft 7 to reverse, release the blockage of the bottom end of the main shaft 7 by the sealing plate 73, and pour the molded concrete into the grouting channel 71 of the main shaft 7. The downward thrust of the spiral conveying blade 72 when rotating in the opposite direction forces the molded concrete to squeeze the cement soil. Without external auxiliary pressurization, the pile barrel 11 and the spiral conveying blade 72 can be used to achieve pressurized pouring of the molded concrete, so that the cement soil is quickly squeezed toward the surrounding side of the bottom expansion pit 62 and into the gap between the pile barrel 11 and the pile hole 61.

[0051] Therefore, only through the high-pressure jet grouting and expansion pile construction equipment of the present application, multiple processes such as soil extraction in the pile barrel 11, soil / rock layer drilling, shotcrete cutting, rotary mixing, and formed concrete pumping and pressurization can be realized simultaneously, which can greatly shorten the time required to switch operations between different large-scale equipment in conventional operations and significantly improve construction efficiency. In addition, the spiral conveying blade 72 can be used as a spiral soil extractor when rotating forward, and can effectively convey the crushed soil in the hollow part of the pile cylinder 11 and the bottom of the pile cylinder 11 to the outside of the pile hole 61; and when rotating reversely, it can have the effect of pressing downward, and can effectively suppress the molded concrete conveyed from the grouting channel 71 of the main shaft 7 from surging in the hollow part of the pile cylinder 11, so that the molded concrete can fully squeeze the cement soil in the bottom expansion pit 62, so that the cement soil can be fully squeezed toward the surrounding side and the gap between the pile cylinder 11 and the pile hole 61 and finally form an upper enclosure 32, further improving the practicality and convenience of the high-pressure jet grouting and bottom expansion pile construction equipment of the present application, can greatly reduce the construction cost during the high-pressure jet grouting and bottom expansion pile construction, and has significant economic benefits.

[0052] Specifically, as some adaptive optimization, refer to Figure 5 and Figure 6 The sealing plate 73 is movably connected to the bottom end of the main shaft 7. When the main shaft 7 moves downward against the soil, the sealing plate 73 blocks the grouting channel 71 at the bottom end of the main shaft 7; when the main shaft 7 is lifted up, the sealing plate 73 is separated from the grouting channel 71 at the bottom end of the main shaft 7.

[0053] In one embodiment, the sealing plate 73 is lifted and arranged at the bottom end of the main shaft 7, and a plurality of sliding rods 731 are fixedly connected to the upper end of the sealing plate 73. A plurality of positioning sleeves 74 that are sleeved and adapted with the plurality of sliding rods 731 are fixedly connected to the inner wall of the grouting channel 71 of the main shaft 7, and an anti-slip head 732 whose outer diameter is larger than that of the sliding rod 731 is fixedly connected to the upper end of the sliding rod 731. Thus, when the main shaft 7 pushes the soil down, the soil layer below pushes the sliding rod 731 up to block the grouting channel 71 to prevent the broken soil from entering the grouting channel 71; and when the main shaft 7 is lifted up, the sealing plate 73 moves down under the action of its own gravity to expose the grouting channel 71. At this time, when the shaped concrete is poured into the grouting channel 71 of the main shaft 7, the shaped concrete can be directly poured into the area where the drill bit 8 is located, without the intervention of an external power mechanism, and the operation is simple. Furthermore, in order to facilitate overflow of the molded concrete, a guide cone 733 may be provided on the upper end surface of the sealing plate 73 to prevent the molded concrete from accumulating on the upper end surface of the sealing plate 73 and affecting the sealing effect of the sealing plate 73 .

[0054] In another embodiment, the sealing plate 73 is hinged at the bottom end of the main shaft 7, and the free end of the sealing plate 73 is connected to a pulling cable extending from the grouting channel 71 to the upper part of the main shaft 7. The free end of the pulling cable can pass through the upper part of the main shaft 7 and extend to the outside of the main shaft 7, and a tightening card is provided on the outside of the pulling cable. When the main shaft 7 moves downward, the pulling cable is pulled so that the sealing plate 73 blocks the grouting channel 71 at the lower end of the main shaft 7, which can prevent the broken soil from entering the grouting channel 71; when the main shaft 7 is lifted, the pulling cable can be released so that the sealing plate 73 can be freely flipped under its own weight to open the grouting channel 71 at the lower end of the main shaft 7, and the sealing plate 73 can also achieve a flexible opening and closing effect on the grouting channel 71.

[0055] In addition, in order to facilitate drilling in different soil and rock layers and adapt to the construction of different pile diameters, Reference Figure 5 and Figure 6 , the above-mentioned drill bit 8 comprises: The base 81 can be detachably mounted on the bottom end of the main shaft 7, and can be specifically fixed on the bottom end of the main shaft 7 in a bolted manner.

[0056] The drilling head 82 can be detachably mounted on the side of the base 81 away from the main shaft 7, and is used for drilling in soil or rock. In the specific setting, considering the patency of the grouting channel 71 during grouting, the drilling head 82 is set on the side of the sealing plate 73 away from the main shaft 7, and the middle of the base 81 is hollow for the movement of the sealing plate 73. And at this time, if the sealing plate 73 is lifted and set on the main shaft 7, at least two groups of sliding rods 731 are set or the cross section of the sliding rod 731 is set to be non-circular to prevent the sealing plate 73 from rotating; if the sealing plate 73 is hinged on the main shaft 7, a plurality of raised and groove structures should be set at the corresponding parts of the sealing plate 73 and the main shaft 7, so that when the sealing plate 73 blocks the main shaft 7, the raised and groove structures can prevent the sealing plate 73 from rotating to reduce damage to the hinged part of the sealing plate 73.

[0057] The stirring head 83 can be detachably mounted on the side wall of the base 81 and is used to stir the plate in the crushed soil / rock mass. There are multiple stirring heads 83 and they surround the drilling head 82 . The outer edge of the stirring head 83 does not protrude from the outer side of the spiral conveying blade 72 .

[0058] Therefore, before construction, a suitable drilling bit 82 can be selected and installed on the base 81 according to the different properties of the soil / rock layer at the bearing layer to ensure that the main shaft 7 can drill into the set soil / rock layer; at the same time, when constructing pile diameters of different design sizes, it is only necessary to assemble the corresponding drill bit 8 to the appropriate main shaft 7, which can greatly reduce the setting cost of construction equipment and thus reduce construction costs. Embodiment five:

[0059] The present application embodiment discloses a high pressure jetting grouting and enlarging pile construction equipment, referring to Figure 7 , which is different from the fourth embodiment in that: Drill bit 8 includes: The base 81 is detachably mounted on the bottom end of the main shaft 7; The movable plate 84 is disposed below the base 81, and a drilling head 82 is detachably mounted on a side of the movable plate 84 away from the base 81; The expansion disk 85 has a large arm hinged to the side of the base 81 and a small arm hinged to the side of the movable plate 84. A plurality of expansion disks 85 are arranged at equal intervals around the base 81. In this embodiment, two expansion disks 85 are arranged. In the specific arrangement, diamond drills, soil scraping plows, etc. can be arranged on the outer side walls of the large arm and the small arm of the expansion disk 85 to adapt to the expansion operation of different soil properties; and The stabilizing column 86 has one end fixedly connected to the movable plate 84 and the other end extending into the grouting channel 71 .

[0060] And, specifically, in order to facilitate the pressure pouring of concrete, the stabilizing column 86 slides through the sealing plate 73 at the bottom end of the main shaft 7; in addition, in another embodiment, a spring 87 can be further provided between the movable plate 84 and the sealing plate 73 and sleeved on the outside of the stabilizing column 86 to keep the expansion disk 85 in a tightened state when there is no external force.

[0061] As a result, when the drill bit 8 follows the main shaft 7 to rotate and move downward in the pile barrel 11, the expansion disk 85 cannot be opened due to the limiting effect of the pile barrel 11 on the expansion disk 85. At this time, the large arm and small arm of the expansion disk 85 are tightened and fitted around the stabilizing column 86, and the drilling head 82 on the movable plate 84 drills the soil or rock layer as the main shaft 7 rotates; and when the drill bit 8 extends out of the pile barrel 11 and is located below the bearing layer, the main shaft 7 is first lifted out of the hollow part of the pile barrel 11, the drilling head 82 at the bottom end of the movable plate 84 is pulled down, and then the main shaft 7 continues to be lowered into the hollow part of the pile barrel 11. As the main shaft 7 gradually moves downward, the movable plate 84 is pressed against the hardened soil or rock layer at the bottom end of the bearing layer, and the large arm and small arm of the expansion disk 85 are gradually opened. As the main shaft 7 continues to rotate, an expansion pit 62 can be formed below the bearing layer by expanding and cutting.

[0062] After the bottom expansion pit 62 is formed, cement slurry is continuously rotated and sprayed into the bottom expansion pit 62 through multiple nozzles 91 to mix the cement slurry with the cut virtual soil stirring plate to form cement soil; then the main shaft 7 is lifted, and at this time the movable plate 84 and the sealing plate 73 both move downward under their own weight, and the grouting channel 71 at the bottom end of the main shaft 7 is opened, and the molded concrete can be pressure-filled into the main shaft 7. After the molded concrete flows out, the main shaft 7 is rotated in the opposite direction, so that the spiral conveying blades 72 push the pressure-filled concrete downward to squeeze the cement soil, so as to ensure the formation of the enlarged head of the high-pressure jet grouting bottom expansion pile in this application. Embodiment six:

[0063] The present application embodiment discloses a high pressure jetting grouting and enlarging pile construction equipment, referring to Figure 8 , which is different from the fifth embodiment in that: A slurry delivery channel 861 connected to the grouting channel 71 is provided in the stabilizing column 86, a through hole 841 connected to the slurry delivery channel 861 is provided on the movable plate 84, a sealing plate 73 is raised and lowered on the movable plate 84 and is used to block the slurry delivery channel 861 when the movable plate 84 is pressed down and fed; a notch is provided at the bottom end of the main shaft 7 for the stabilizing column 86 to slide through.

[0064] Therefore, after the drilling head 82 on the movable plate 84 is disassembled, when the main shaft 7 is lowered to the bottom of the hollow part of the pile cylinder 11, the movable plate 84 presses against the hardened soil layer or rock layer at the bottom of the bearing layer, and the bottom expansion pit 62 can also be formed under the bearing layer by expanding the diameter and cutting. Then, when the main shaft 7 is lifted, the sealing plate 73 on the movable plate 84 moves downward under its own gravity, so that the grouting channel 861 is opened. At this time, when the molded concrete is transported to the grouting channel 71, it can be transported to the bottom expansion pit 62 through the bottom of the through hole 841 on the movable plate 84 through the grouting channel 861, which can also realize the convenient transportation of the molded concrete.

[0065] Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second", "third" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "One" or "one" and similar words do not indicate a quantitative limit, but indicate that there is at least one. "Include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0066] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high pressure jetting grouting pile, characterized in that: include: A pile body (1) is formed in a pile hole (61), and a bottom expansion pit (62) having a diameter greater than that of the pile body (1) is formed in the original soil (6) at the lower part of the pile body (1); The enlarged body (2) is formed by curing the molded concrete that is subsequently pressed into the bottom enlargement pit (62) and is spherical in shape; The lower enclosure (31) is formed by mixing cement slurry and loose soil that are first pressed into the bottom expansion pit (62) to form cement soil, which is then squeezed around by the molded concrete that is subsequently pressed and then solidified. The solidified lower enclosure (31) is wrapped around the periphery of the expansion body (2); The upper enclosure (32) is formed by mixing cement slurry and loose soil that are first pressed into the bottom expansion pit (62) to form cement soil, and then the molded concrete that is subsequently pressed overflows into the gap between the pile body (1) and the pile hole (61) and solidifies, and surrounds the circumference of the bottom end of the pile body (1); as well as The reinforcement body (4) is formed by mixing cement slurry with loose soil that is first pressed into the bottom expansion pit (62) to form cement soil, and then the molded concrete that is subsequently pressed into the bottom expansion pit (62) penetrates into the original soil body (6) outside the bottom expansion pit (62) and solidifies, and surrounds the circumference of the lower enclosure (31).

2. The high pressure jetting grouting pile according to claim 1 is characterized in that: An anti-pullout member (5) is connected between the enlarged body (2) and the pile body (1); one end of the anti-pullout member (5) is buried in the pile body (1) and the other end is buried in the enlarged body (2).

3. A high pressure jetting grouting and enlarging pile construction method, characterized in that: The following steps are involved: S1. Equipment enters the site and the pile position is marked according to the construction requirements; S2. Take the corresponding fixed pile tube (11) according to the designed pile diameter and press it down to the bearing layer at the pile position; S3. Taking out the soil in the hollow portion of the pile cylinder (11); S4. In the original soil (6) at the bottom of the pile cylinder (11), a bottom expansion pit (62) is formed by jetting cutting or diameter expansion cutting. If the jetting cutting method is adopted, the injected cement slurry is mixed with the cut loose soil to form cement soil. If the diameter expansion cutting method is adopted, after the bottom expansion pit (62) is formed, cement slurry is injected into the bottom expansion pit (62) and mixed with the cut loose soil to form cement soil. S5. Pressurizing the molded concrete into the bottom expansion pit (62) and limiting the molded concrete from flowing upward in the hollow portion of the pile cylinder (11), so that the cement soil in the bottom expansion pit (62) is squeezed into the original soil (6) around the bottom expansion pit (62) and into the gap between the pile cylinder (11) and the pile hole (61); S6. pouring concrete into the hollow portion of the pile cylinder (11) to form a pile body (1).

4. The high pressure jetting grouting pile according to claim 3, characterized in that: In step S5, after the molded concrete and cement soil in the bottom expansion pit (62) are solidified, the solidified molded concrete forms an expanded body (2), and after the cement soil in the bottom expansion pit (62) is solidified, it forms a lower enclosure (31) wrapped around the outside of the expanded body (2), and the cement soil in the gap between the pile cylinder (11) and the pile hole (61) is solidified to form an upper enclosure (32) that wraps around the bottom end of the rail pile cylinder (11) and is connected to the lower enclosure (31), and the cement soil on the pit wall of the bottom expansion pit (62) that penetrates into the original soil is solidified to form a reinforcement body (4) wrapped around the outer periphery of the lower enclosure (31).

5. The high pressure jetting grouting and enlarging pile construction method according to claim 3 is characterized in that: If anti-pullout piles are constructed, in step S6, before the formed concrete in the enlarged bottom pit (62) begins to set, an anti-pullout member (5) is inserted into the enlarged bottom pit (62), and the upper portion of the anti-pullout member (5) extends into the hollow portion of the pile cylinder (11).

6. The high pressure jetting grouting and enlarging pile construction method according to claim 3 is characterized in that: If cast-in-place piles are to be constructed, the pile cylinder (11) in step S2 is set as a steel pipe (111) having an inner diameter equal to the designed pile diameter; If prefabricated piles are used, the pile cylinder (11) in step S2 is set as a prestressed pipe pile (112) having an outer diameter equal to the designed pile diameter.

7. The high pressure jetting grouting and enlarging pile construction method according to claim 3 is characterized in that: The diameter of the bottom expansion pit (62) formed in step S4 is not less than 1.5 times the designed pile diameter, and the depth is not less than 500 mm.

8. The high pressure jetting grouting and enlarging pile construction method according to claim 3 is characterized in that: In step S4, cement slurry is sprayed into the original soil (6) at the bottom of the pile cylinder (11) by a high-pressure nozzle, and the lower the compression modulus of the original soil (6) at the bottom of the pile cylinder (11), the smaller the spraying pressure.

9. A high-pressure jetting grouting and bottom-enlarging pile construction equipment, used to implement the high-pressure jetting grouting and bottom-enlarging pile construction method according to any one of claims 3 to 8, characterized in that: include: A main shaft (7) having a grouting passage (71) formed therein; A spiral conveying blade (72) is spirally wound around the outer peripheral wall of the main shaft (7) and is extended along the length direction of the main shaft (7); A drill bit (8) mounted on the bottom end of the main shaft (7) and used for drilling into a soil layer or a rock layer and stirring the soil; A plurality of nozzles (91) are provided and mounted on the bottom end of the main shaft (7); A slurry delivery pipe (92) is fixedly connected to the outer wall of the main shaft (7) along the length direction of the main shaft (7), and the slurry delivery pipe (92) is connected to the plurality of nozzles (91); a sealing plate (73) movably mounted on the bottom end of the main shaft (7) and used to seal the grouting channel (71); and The rotary lifting machine is used to drive the main shaft (7) to rotate forward, reverse or lift.

10. The high pressure jetting grouting and enlarging pile construction equipment according to claim 9, characterized in that: When executing step S3, the rotary lifting machine is controlled to drive the main shaft (7) to rotate forward and to continuously insert the main shaft (7) into the hollow portion of the pile fixing cylinder (11), the soil is crushed by means of the drill bit (8), and the crushed soil is output upward by the spiral conveying blade (72).

11. The high pressure jetting grouting and enlarging pile construction equipment according to claim 10, characterized in that: When executing step S4, the rotary lifting machine is controlled to move the main shaft (7) downward to extend at least 500 mm from the lower end of the pile fixing cylinder (11), the main shaft (7) is kept in a rotating state, and cement slurry of a set pressure is delivered to the slurry delivery pipe (92), so that the cement slurry is sprayed out from the plurality of nozzles (91) to jet-cut the surrounding soil; at the same time, the drill bit (8) stirs the cut soil and cement slurry while rotating to form cement soil.

12. The high pressure jetting grouting and enlarging pile construction equipment according to claim 11, characterized in that: When executing step S5, the rotary lifting machine is controlled to drive the main shaft (7) to reverse, the sealing of the bottom end of the main shaft (7) by the sealing plate (73) is released, and the molded concrete is poured into the grouting channel (71) of the main shaft (7). The molded concrete is forced to squeeze the cement soil by means of the downward thrust of the spiral conveying blade (72) when rotating in the opposite direction, so that the cement soil is squeezed toward the peripheral side and into the gap between the pile cylinder (11) and the pile hole (61).

13. The high pressure jetting grouting and enlarging pile construction equipment according to claim 12, characterized in that: The sealing plate (73) is movably connected to the bottom end of the main shaft (7); when the main shaft (7) moves downward against the soil, the sealing plate (73) blocks the grouting channel (71) at the bottom end of the main shaft (7); when the main shaft (7) is lifted upward, the sealing plate (73) is separated from the grouting channel (71) at the bottom end of the main shaft (7).

14. The high pressure jetting grouting and enlarging pile construction equipment according to any one of claims 9 to 13, characterized in that: The drill bit (8) comprises: A base (81) is detachably mounted on the bottom end of the main shaft (7); A drilling head (82) is detachably mounted on a side of the base (81) away from the main shaft (7) and is used for drilling in soil or rock; The stirring head (83) is detachably mounted on the side wall of the base (81) and is used to stir the plate in the crushed soil / rock mass. The stirring heads (83) are provided in plurality and surround the circumference of the drilling head (82).

15. The high pressure jetting grouting and enlarging pile construction equipment according to any one of claims 9 to 13, characterized in that: The drill bit (8) comprises: A base (81) is detachably mounted on the bottom end of the main shaft (7); A movable plate (84) is arranged below the base (81), and a drilling head (82) is detachably mounted on a side of the movable plate (84) facing away from the base (81); an expanding disk (85), the upper arm of which is hinged to the side of the base (81) and the lower arm of which is hinged to the side of the movable plate (84), and a plurality of expanding disks (85) are arranged at equal intervals around the base (81); and A stabilizing column (86) has one end fixedly connected to the movable plate (84) and the other end extending into the grouting channel (71).

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