High-pressure jet pile machine suitable for the construction process of consolidation and expansion piles

Abstract

The present application provides a high-pressure rotary jet pile machine suitable for the construction process of consolidation and expansion piles, which belongs to the field of pile foundation construction. A plurality of cement-soil composite monomers are connected to form a cement-soil composite consolidation body. On the one hand, the outer diameter of the cement-soil composite consolidation body is increased, and the expansion pile is shorter than the traditional cast-in-place pile. On the other hand, cement slurry is not sprayed at the center of the cement-soil composite consolidation body, which reduces the amount of cement used. During the construction of the cement-soil composite monomer, when the drill rod is rotated to the cement nozzle facing inward, the round seat is rotated to the injection hole downward or upward, so that less cement is diffused to the main pile position, avoiding excessive cement from being brought out when drilling holes in the main pile position later, reducing the difficulty of expansion construction and improving construction efficiency. When the drill rod is rotated to the cement nozzle facing outward, the first control structure drives the driving structure to rotate the round seat to the injection hole horizontally outward, so that the injected cement is diffused farther to the outside away from the main pile position, so that the outer diameter of the formed cement-soil composite consolidation body is increased.

Description

Technical Field

[0001] The present application belongs to the technical field of pile foundation construction, and more specifically, to a high-pressure rotary jet pile machine suitable for the construction process of consolidated expanded plate piles. Background Art

[0002] The consolidated expanded plate pile technology organically integrates the pile expansion technology and the composite foundation treatment technology, and innovates it into a new pile foundation process technology. The core of this technology is to carry out the pile-making process of expanding the plate in a pre-set consolidated body to form a composite pile structure in which the plate protrudes from the pile body, the plate is embedded in the consolidated body and is integrated with the consolidated body.

[0003] However, in the current construction process of consolidated expanded plate piles, it is necessary to first form a consolidated body at a predetermined position, and then drill holes in the consolidated body and expand the plate to form a plate cavity. In this process, the drill will pass through the consolidated body cast in the early stage, which increases the difficulty of drilling and causes waste of cement slurry in the early stage of the consolidated body. Therefore, it is necessary to further improve the construction technology and construction equipment of conventional expanded plate pile foundation, and at the same time avoid the phenomenon of hole collapse in the expanded plate pile construction to ensure the construction quality. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a high-pressure rotary jet pile machine suitable for the consolidation expanded plate pile construction process, so as to solve to a certain extent the technical problems existing in the existing conventional expanded plate pile foundation construction technology, that is, drilling holes through the consolidation body during the construction process, resulting in great difficulty in drilling and waste of cement slurry of the consolidation body.

[0005] To achieve the above purpose, the technical solution adopted in this application is:

[0006] On the one hand, a consolidation expanded plate pile construction process is provided, comprising:

[0007] The cement-soil composite consolidation body is constructed by using a high-pressure rotary jet pile machine to perform multiple drilling operations around the main pile position; during each drilling operation, grouting is sprayed from bottom to top at multiple predetermined elevation positions to form cement-soil composite monomers; the cement-soil composite monomers formed at the same predetermined elevation position in each drilling operation are connected to form a cement-soil composite consolidation body;

[0008] Pile hole construction: using a rotary drilling rig to rotary drill pile holes at the main pile position, and forming a disc cavity with an enlarged diameter on each cement-soil composite consolidation body;

[0009] During the steel cage installation construction, the steel cage will be lowered into the pile hole;

[0010] Underwater concrete pouring, pouring concrete into the pile hole from bottom to top through a conduit to form the pile body.

[0011] In some embodiments, in the cement-soil composite consolidation body construction step, a double ultra-high pressure triple pipe method is used for construction;

[0012] In the construction of a single cement-soil composite consolidation body, cement is P.O42.5 ordinary Portland cement, and the water-cement ratio of cement slurry is 1.0; during grouting, the drill rod lifting speed is 5~20cm / min, the drill rod rotation speed is 18~25r / min, the pressure of the high-pressure cement slurry jet is 36~40MPa, the cement slurry flow rate is 220~240L / min, the air flow pressure is 1.3MPa, and the gas flow rate is 5~8m3 / min;

[0013] During the construction of a single cement-soil composite consolidation body, the high-pressure rotary jet pile driver drills to the specified elevation and then performs jet grouting. The jet grouting should adopt the above-mentioned parameters and be carried out from bottom to top according to the triple pipe method construction process.

[0014] In certain embodiments, in the cement-soil composite consolidation body construction steps, during each drilling operation, the verticality of the drill rod should be controlled within 0.2 degrees, the center of the guide frame of the drill rod should be consistent with the center of the power head, and the deviation between the drilling position and the designed pile position should not exceed 50 mm.

[0015] In some embodiments, the pile hole construction step includes:

[0016] Measure and stake out, confirm the main pile position data, use the total station to stake out the main pile position on the spot through the coordinate method, and stake out the secondary pile position;

[0017] The casing is buried and positioned by digging a pit, and the bottom and the outer sides of the casing are backfilled with clay soil and compacted in layers; the inner diameter of the casing is 30cm larger than the pile diameter, the buried depth of the casing is 2.7m, the plane position deviation between the center of the casing and the center of the main pile position is not more than 5cm, the vertical inclination is not more than 1%, and the top of the casing is 0.3m higher than the original ground;

[0018] The pile hole and the plate cavity are formed. The drilling rig first drills the hole, and after drilling to the cement-soil composite consolidation body at the predetermined elevation, the plate expansion construction is carried out. The drilling construction and the plate expansion construction are carried out alternately until the predetermined depth is reached;

[0019] The first hole cleaning is to use a drilling rig to clean the slag. The thickness of the sediment after the first hole cleaning shall not be greater than 200mm, and the mud index shall meet the requirements; when cleaning the hole, the water level in the hole should be kept at about 0.5m below the casing;

[0020] After the hole is completed, the pile hole and the cavity are scanned and self-checked with a caliper to measure whether the pile hole and the cavity meet the following requirements: the hole diameter is not less than the designed pile diameter, the hole inclination is allowed to have a deviation of 1%, the sediment thickness at the bottom of the hole is allowed to be ≤200, the diameter is allowed to have a deviation of -50mm, the cavity elevation is allowed to have a deviation of ±100mm, and the cavity height is allowed to have a deviation of -100mm; after the hole is completed and the cavity is tested, the second hole cleaning is carried out;

[0021] The second hole cleaning is done by slurry replacement method. When cleaning the hole, the water level in the hole should be kept at about 0.5m below the casing.

[0022] The beneficial effect of the consolidation and expansion pile construction process provided in the embodiment of the present application is that compared with the prior art, the consolidation and expansion pile construction process in the embodiment of the present application, by performing multiple drilling operations around the main pile position, forms a cement-soil composite consolidation body connected by multiple cement-soil composite monomers. On the one hand, the outer diameter of the cement-soil composite consolidation body is increased, and the expanded pile is shorter than the traditional cast-in-place pile. On the other hand, cement slurry is not sprayed at the center position of the cement-soil composite consolidation body, thereby reducing the amount of cement. When the pile hole is rotary drilled at the main pile position, the pile hole passes through the cement-soil composite consolidation body, and the cement soil body at the center position of the cement-soil composite consolidation body is dug out, and the consolidation body is expanded, so that the cast pile body is connected to the cement-soil composite consolidation body.

[0023] Another technical solution adopted by the present application is to provide a high-pressure rotary jet pile machine, including: a consolidation and expansion pile construction process applicable to any of the above; the high-pressure rotary jet pile machine includes a main machine and a drill rod, and the drill rod includes:

[0024] The outer casing has a cement nozzle, a water nozzle and an air nozzle on the side wall of one end where the drill bit is installed;

[0025] An inner sleeve is coaxially sleeved inside the outer sleeve; a cylindrical gap between the inner sleeve and the outer sleeve forms a cement slurry cavity, and the cement slurry cavity is connected to the cement nozzle; and

[0026] The inner second sleeve is coaxially sleeved inside the inner one sleeve; the cylindrical gap between the inner second sleeve and the inner one sleeve forms a water flow cavity, and the water flow cavity is connected with the water flow nozzle through an inner connecting pipe; the inner second sleeve forms an air flow cavity, and the air flow cavity is connected with the air flow nozzle through the inner second connecting pipe;

[0027] Wherein, the cement nozzle comprises:

[0028] A round seat having a through injection hole; the round seat is embedded in a circular cavity on the side wall of the outer casing, and the outer end of the injection hole faces the outside of the outer casing, and the inner end is connected to the cement slurry cavity; the round seat can swing along the axial plane of the outer casing, and the outer end of the injection hole changes the injection angle through the swing of the round seat; and

[0029] A driving structure, comprising a gear and a rack; the gear is connected to the round seat; the rack is meshed with the gear to drive the round seat to swing through the gear; and

[0030] The high-pressure rotary jet pile driver also includes a first control structure, which includes a first push-up cam and a first push rod; the first push-up cam is arranged at the top of the drill rod and is fixedly arranged; the first push rod is arranged on the inner wall of the outer casing and is slidably arranged along the axial direction, and one end is driven by the first push-up cam and the other end drives the rack;

[0031] During the rotation of the drill rod, the first push cam drives the first push rod to axially reciprocate; when the drill rod rotates until the cement nozzle faces inward, the first push rod drives the round seat to rotate through the rack and gear until the injection hole is tilted downward or upward; when the drill rod rotates until the cement nozzle faces outward, the first push rod drives the round seat to rotate through the rack and gear until the injection hole is horizontally outward.

[0032] In some embodiments, the top of the drill pipe is provided with a first rotary joint connected to the outer casing; the first push-out cam is a cylindrical cam sleeved on the top of the outer casing, and the first push-out cam is fixed by the first rotary joint;

[0033] The upper end of the first pushing rod passes through the outer sleeve and is provided with a roller embedded in the cam groove of the first pushing cam.

[0034] In some embodiments, the inner sleeve further comprises:

[0035] A first blocking plate is disposed on the inner wall of the inner sleeve and is slidably disposed along the axial direction to block or open the inner connecting tube;

[0036] The second control structure comprises a second push cam and a second push rod; the second push cam is arranged at the top of the drill rod and is fixedly arranged; the second push rod is arranged on the inner wall of the inner sleeve and is slidably arranged along the axial direction, and one end of the second push cam drives the first blocking plate, and the other end drives the first blocking plate;

[0037] During the rotation of the drill rod, the second push cam drives the second push rod to move axially back and forth; when the drill rod is rotated to the point where the cement nozzle faces inward, the second push rod drives the first blocking plate to at least partially cover the inner connecting tube; when the drill rod is rotated to the point where the cement nozzle faces outward, the second push rod drives the first blocking plate to open the inner connecting tube.

[0038] In some embodiments, the top of the drill pipe is provided with a second rotary joint connected to the inner sleeve; the second push-out cam is a cylindrical cam sleeved on the top of the inner sleeve, and the second push-out cam is fixed by the second rotary joint;

[0039] The upper end of the second push rod passes through the outside of the inner sleeve and is provided with a roller embedded in the cam groove of the second push cam.

[0040] In some embodiments, the inner second sleeve further comprises:

[0041] A second blocking plate is provided on the inner wall of the inner second sleeve and is slidably arranged along the axial direction to block or open the inner second connecting pipe;

[0042] The third control structure comprises a third push cam and a third push rod; the third push cam is arranged at the top of the drill rod and is fixed; the third push rod is arranged on the inner wall of the inner second casing and is slidably arranged along the axial direction, and one end is driven by the third push cam and the other end drives the second blocking plate;

[0043] During the rotation of the drill rod, the third push cam drives the third push rod to move axially back and forth; when the drill rod rotates to the point where the cement nozzle faces inward, the third push rod drives the second blocking plate to at least partially cover the two inner connecting tubes; when the drill rod rotates to the point where the cement nozzle faces outward, the third push rod drives the second blocking plate to open the two inner connecting tubes.

[0044] In some embodiments, the top of the drill pipe is provided with a third rotating joint connected to the inner second casing; the third ejection cam is a cylindrical cam sleeved on the top of the inner second casing, and the third ejection cam is fixed by the third rotating joint;

[0045] The upper end of the third push rod passes through the outside of the inner two sleeves and is provided with a roller embedded in the cam groove of the third push cam.

[0046] The beneficial effect of the high-pressure rotary jet pile machine provided in the embodiment of the present application is that: compared with the prior art, the high-pressure rotary jet pile machine in the embodiment of the present application can be applied to any of the above-mentioned consolidation expansion pile construction processes, and the first push rod is pushed by the first push cam during the rotation of the drill rod, so that the first push rod reciprocates up and down, so that the first push rod drives the round seat of the cement nozzle to rotate through the gear and the rack, thereby changing the direction of the cement slurry sprayed from the spray hole;

[0047] When the drill rod rotates until the cement nozzle faces inward, the first control structure drives the driving structure to rotate the round seat until the injection hole is tilted downward or upward, so that the injected cement diffuses less toward the main pile position, reducing the difficulty of drilling holes and expanding the plate at the main pile position in the later stage, and also reducing the excessive removal of cement slurry injected in the early stage, thereby reducing waste;

[0048] Moreover, the use of downward or upward deflected spraying through the spray hole can not reduce the spraying amount of cement compared with the conventional closed spray hole method, so that a large amount of cement can be diffused to the surrounding under pressure, so that the cement-soil composite monomers adjacent to the same predetermined elevation position are more closely connected together;

[0049] When the drill rod rotates until the cement nozzle faces outward, the first control structure drives the driving structure to rotate the round seat until the injection hole faces horizontally outward, so that the injected cement spreads farther to the outside away from the main pile position, thereby increasing the outer diameter of the formed cement-soil composite consolidation body. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0051] Figure 1 A specific construction flow chart of the consolidation and expansion pile construction process provided in the embodiment of the present application;

[0052] Figure 2 A specific construction flow chart of a cement-soil composite monomer in the consolidation and expansion pile construction process provided in the embodiment of the present application;

[0053] Figure 3 A specific construction flow chart of the pile hole construction steps in the consolidation and expansion pile construction process provided in the embodiment of the present application;

[0054] Figure 4 A partial view of the upper end of the drill rod of the high-pressure rotary jet pile driver provided in an embodiment of the present application;

[0055] Figure 5 A schematic diagram of the internal structure of a drill rod of a high-pressure rotary jet pile driver provided in an embodiment of the present application;

[0056] Figure 6 for Figure 5 The enlarged view of point A in the middle;

[0057] Figure 7 A schematic diagram of the internal structure of the upper end of the inner sleeve of the drill rod of the high-pressure rotary jet pile driver provided in an embodiment of the present application;

[0058] Figure 8 A schematic diagram of the internal structure of the lower end of the inner sleeve of the drill rod of the high-pressure rotary jet pile driver provided in an embodiment of the present application;

[0059] Fig. 9 A schematic diagram of the internal structure of the upper end of the inner second casing of the drill rod of the high-pressure rotary jet pile driver provided in an embodiment of the present application;

[0060] Fig.10 A schematic diagram of the internal structure of the lower ends of the inner second casings of the drill rod of the high-pressure rotary jet pile driver provided in an embodiment of the present application.

[0061] Among them, the reference numerals in the figure are:

[0062] 2-drill pipe; 21-outer casing; 211-cement slurry chamber; 22-inner casing; 221-water flow chamber; 222-inner connecting pipe one; 23-inner second casing; 231-air flow chamber; 232-inner second connecting pipe; 24-cement nozzle; 241-round seat; 242-injection hole; 243-gear; 244-rack; 25-water flow nozzle; 251-first blocking plate; 26-air flow nozzle; 261-second blocking plate; 3-first rotary joint; 31-first push cam; 32-first push rod; 4-second rotary joint; 41-second push cam; 42-second push rod; 5-third rotary joint; 51-third push cam; 52-third push rod. DETAILED DESCRIPTION

[0063] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0064] Please also read Figures 1 to 3 The following is an explanation of the consolidation and expansion pile construction process provided in the embodiment of the present application. A consolidation and expansion pile construction process comprises:

[0065] The construction of cement-soil composite consolidation body uses a high-pressure rotary jet pile machine to perform multiple drilling operations around the main pile position; during each drilling operation, grouting is sprayed from bottom to top at multiple predetermined elevation positions to form cement-soil composite monomers; the cement-soil composite monomers formed at the same predetermined elevation position by each drilling operation are connected to form a cement-soil composite consolidation body;

[0066] Pile hole construction: using a rotary drilling rig to rotary drill pile holes at the main pile position, and forming a disc cavity with an enlarged diameter on each cement-soil composite consolidation body;

[0067] During the steel cage installation construction, the steel cage will be lowered into the pile hole;

[0068] Underwater concrete pouring, pouring concrete into the pile hole from bottom to top through a conduit to form the pile body.

[0069] Compared with the prior art, the consolidation and expansion pile construction process of the embodiment of the present application performs multiple drilling operations around the main pile position to form a cement-soil composite consolidation body connected by multiple cement-soil composite monomers. On the one hand, the outer diameter of the cement-soil composite consolidation body is increased, and the pile length is shortened compared with the traditional cast-in-place pile. On the other hand, cement slurry is not sprayed at the center position of the cement-soil composite consolidation body, which reduces the amount of cement. When the pile hole is rotary drilled at the main pile position, the pile hole passes through the cement-soil composite consolidation body, and the cement soil body at the center position of the cement-soil composite consolidation body is dug out to expand the consolidation body, so that the cast pile body is connected to the cement-soil composite consolidation body.

[0070] Before the formal construction of the consolidation and expansion pile construction process in this embodiment, the construction preparation work is first carried out, and the construction preparation work includes:

[0071] (1) Before the construction of consolidation expansion piles, the site should be leveled, debris should be cleared, temporary power and water systems should be established, and a mud pool should be constructed.

[0072] (2) Drilling rigs must be inspected after entering the site. The drill bit diameter and length, drill rod length and quantity, etc. of the drilling rigs should be measured and marked one by one and must not be mixed. After the drilling rig is positioned, the relevant parameters of the drilling rig (such as the number and total length of drill rods, drill plate elevation, drilling time, etc.) should be made into identification plates and hung on each drilling rig. During the drilling process, the height difference of the four corners of the drill plate should be measured every four hours to ensure the verticality of the drill rod.

[0073] (3) Before construction, pile positions are marked and pile guards are set. The pile positions are located by total station, welded steel piles are marked, and the center of the pile position is determined by the center of the crosshairs. The deviation between the central axis of the casing and the designed pile position is controlled to be no more than 5 cm, and the vertical inclination is less than 1 / 150. The next process (drilling rig in place) is carried out after the pile position, pile guards and casing are tested and qualified by the quality inspection engineer and the on-site supervision engineer.

[0074] After the construction preparation work is completed, a crawler RJP (Rodin Jet Pile, RJP method is to use the kinetic energy of ultra-high pressure jet fluid to destroy the organizational structure of the foundation, mix and stir these destroyed soil particles and hardened materials to form a large diameter pile body) pile driver equipped with dual high-pressure pumps to carry out the construction of cement soil composite monomers. The specific process flow is shown in Figure 2 By forming a plurality of cement-soil composite monomers at the same predetermined elevation, the plurality of cement-soil composite monomers are connected to form a cement-soil composite consolidation body, and then a disc cavity with an enlarged diameter is formed on each cement-soil composite consolidation body in the pile hole construction step.

[0075] After the construction of the cement-soil composite consolidation body is completed, the pile hole is rotary excavated at the main pile position by using a drilling rig. When the drilling rig reaches the position of the embedded consolidation body, the drilling rig performs the expansion plate construction in the consolidation body. The drilling and expansion plate construction are carried out alternately until the hole reaches the predetermined depth, and the steel cage is lowered to pour concrete. Specifically, the pile hole construction, steel cage installation construction and underwater concrete pouring can refer to the existing construction process, which will not be repeated here.

[0076] See also Figure 1 and Figure 2 As a specific implementation method of the consolidation expansion pile construction process provided by the present application, in the cement-soil composite consolidation body construction step, the double ultra-high pressure triple pipe method is used for construction;

[0077] In the construction of a single cement-soil composite consolidation body, P.O42.5 ordinary Portland cement is used, and the water-cement ratio of the cement slurry is 1.0. Solid waste cementitious materials can be used to replace part of the cement to prepare solid waste cement slurry; during grouting, the drill rod lifting speed is 5~20cm / min, the drill rod rotation speed is 18~25r / min, the pressure of the high-pressure cement slurry jet is 36~40MPa, the cement slurry flow rate is 220~240L / min, the air flow pressure is 1.3MPa, and the gas flow rate is 5~8m3 / min;

[0078] During the construction of a single cement-soil composite consolidation body, the high-pressure rotary jet pile driver drills to the specified elevation and then sprays grouting. The spray grouting should use the above-mentioned parameters and be carried out from bottom to top according to the triple pipe construction process.

[0079] In this embodiment, by selecting appropriate cement slurry ratio, drill rod rotation and lifting parameters, cement slurry jet parameters, and air flow parameters, the volume of the formed cement-soil composite monomer can be expanded, while the formation of bubble cavities can be avoided, thereby improving the strength of the formed cement-soil composite monomer.

[0080] See also Figure 2As a specific implementation method of the consolidation expanded plate pile construction process provided in this application, in the cement-soil composite consolidation body construction step, each time the drilling operation is performed at the secondary pile position, the verticality of the drill rod must be controlled within 0.2 degrees, the center of the guide frame of the drill rod should be consistent with the center of the power head, and the deviation between the drilling position and the designed pile position shall not be greater than 50 mm.

[0081] In this embodiment, the positions of the cement-soil composite monomers formed by the same drilling operation should be accurate, so as to ensure that the cement-soil composite monomers formed by each drilling operation at the same predetermined elevation position can be connected to form a cement-soil composite consolidation body.

[0082] In a more detailed embodiment, in the construction steps of the cement-soil composite consolidation body, the specific construction method and technical measures for each drilling operation include the following parts (1) to (9):

[0083] (1) Leveling the construction site

[0084] Before construction, the depth and location of underground obstacles should be ascertained, and exploration pits should be dug and clearly marked. Appropriate protection measures should be taken for civil power and telecommunication lines within the construction area, and necessary written procedures should be completed.

[0085] The construction waste in the construction area must be cleaned up, and then the site must be leveled and compacted, and water and electricity must be brought to the site. Fences should be set up around the site.

[0086] (2) Measurement and positioning

[0087] ① Obtain the main pile position of the bored pile from the Engineering and Technology Department, clearly mark and number the calibrated reference points, and take protective measures.

[0088] ② Place the secondary piles of RJP from the main piles and make clear and reliable pile position marks. In addition, measurement records should be kept for review.

[0089] (3) Pile driver in place

[0090] The RJP pile driver is leveled and fixed in place, and equipped with air compressors, cement slurry preparation systems and other machinery and materials. The pile driver is aligned and adjusted to verticality. The RJP equipment has a self-leveling device, which is used in conjunction with project measurement and setting out to control the verticality of the pile foundation; the allowable inclination of the rotary jet pipe shall not exceed 0.5%, and then drilling is carried out. The triple pipe method is used for construction, with two ultra-high pressure pumps and high-pressure pipes to ensure the pressure and spray radius of the nozzle.

[0091] RJP pile driver verticality assurance measures:

[0092] 1. The verticality of the drill rod should be controlled within 0.2 degrees.

[0093] 2. The gap between the power head and the drill rod should not be too large.

[0094] 3. The center of the drill rod guide frame should be consistent with the center of the power head.

[0095] 4. The drill pipe and the square head of the drill pipe cannot be skewed.

[0096] 5. The drill bit square box and center cone cannot be skewed.

[0097] 6. The deviation between the drilling position and the designed pile position shall not exceed 50mm.

[0098] 7. The distance between the drilling rig and the high-pressure grouting pump should not be too far.

[0099] 8. The drill rod of the drilling rig must be positioned using a drill rod guide frame.

[0100] (4) Secondary pile drilling

[0101] The purpose of drilling the secondary pile position is to insert the grouting nozzle on the drill rod to the predetermined elevation position, form a cement-soil composite monomer at the predetermined elevation position, and then form a cement-soil composite consolidation body, and stabilize the geology of the pile foundation expansion position by pre-embedded consolidation body. To prevent mud and sand from clogging the nozzle, water should be injected while drilling, and the water pressure should generally not exceed 1Mpa.

[0102] The deviation between the drilling position and the designed position shall not exceed 50mm. Detailed drilling records should be made during the drilling process.

[0103] During the drilling process, the verticality of the drill rod should be observed at all times, and any deviation should be adjusted in time.

[0104] (5) Preparation of curing agent slurry

[0105] While the RJP pile driver is drilling, the curing agent slurry (cement slurry, etc.) is mixed in the background and poured into the aggregate hopper before grouting. The slurry is prepared strictly according to the design requirements, and the water-cement ratio is controlled at 1.0.

[0106] When calculating the amount of cement added according to the requirements of the drawings, the specific gravity of the soil is 19KN / m³, and the cement addition ratio is 15%. After calculation, the amount of cement added per cubic solid body is: 19KN / m³ / 10×15%=285kg. Each solid body is composed of 5 cylinders with a diameter of 1.4 meters and a height of 2m. The cement consumption of each solid body is: 0.7×0.7×π×2×5×285=4385kg.

[0107] (6) Rotary grouting

[0108] A drilling operation requires spraying grouting at multiple predetermined elevations to form multiple cement-soil composite monomers from bottom to top. During the operation, the drill rod should be drilled to the deepest point, then gradually lifted, and sprayed with grouting from bottom to top to form each cement-soil composite monomer.

[0109] As the drill rod of the RJP pile driver is lifted, grouting can be sprayed only after the nozzle reaches the predetermined elevation. When the grouting parameters reach the specified values, it can be sprayed, rotated and lifted at the same time, and finally cement-soil composite monomers are formed at each predetermined elevation.

[0110] During the jet grouting process, construction should be carried out strictly in accordance with the design and test pile parameters.

[0111] The overlap length of the grouting pipe when lifting in sections shall not be less than 100mm.

[0112] In the process of high-pressure jet grouting, if there are abnormal conditions such as sudden pressure drop, increase or abnormal grouting (the amount of grouting is greater than 20% of the grouting amount or no grouting) the causes should be identified and timely measures should be taken.

[0113] The slurry should not be stirred for more than 4 hours. If it exceeds this time, the slurry should be disposed of as waste.

[0114] Construction records should be kept during rotary grouting construction and the records should be detailed and accurate.

[0115] (7) Tube removal and flushing

[0116] After the rotary jetting construction is completed, the grouting pipe should be pulled out quickly and the pipe should be flushed with clean water. In order to prevent the slurry from solidifying and shrinking and affecting the pile top elevation, measures such as grouting backfilling or secondary grouting can be adopted in the original hole position if necessary.

[0117] (8) Pile driver displacement

[0118] The motor should be turned off first, then all the grouting pipes of the RJP pile driver should be lifted out of the ground, and then the pile driver should be moved to the new pile position.

[0119] (9) Construction records

[0120] During the construction process, the foreman is responsible for filling in the construction record, which records in detail the pile position number, pile length, cross-sectional area, sinking (lifting) mixing and spraying time and depth, cement dosage, test block number, cement mixing ratio, and water-cement ratio. During the construction process, the quality inspector, technical person in charge, and on-site supervision engineer supervise the construction, and the construction record is submitted to the project supervisor for approval.

[0121] See also Figure 1 and Figure 3 As a specific implementation method of the consolidation expansion pile construction process provided in this application, the pile hole construction steps include:

[0122] Measure and stake out, confirm the main pile position data, use the total station to stake out the main pile position on the spot through the coordinate method, and lay out the secondary pile position; determine the secondary pile position based on the main pile position to ensure that the relative position between the secondary pile position and the main pile position is more accurate;

[0123] The casing is buried and positioned by digging a pit, and the bottom and the outer sides of the casing are backfilled with clay soil and compacted in layers; the inner diameter of the casing is 30cm larger than the pile diameter, the buried depth of the casing is 2.7m, the plane position deviation between the center of the casing and the center of the main pile position is no more than 5cm, the vertical inclination is no more than 1%, and the top of the casing is 0.3m higher than the original ground;

[0124] The pile hole and the plate cavity are formed. The drilling rig first drills the hole, and after drilling to the cement-soil composite consolidation body at the predetermined elevation, the plate expansion construction is carried out. The drilling construction and the plate expansion construction are carried out alternately until the predetermined depth is reached;

[0125] The first hole cleaning is to use a drilling rig to clean the slag. The thickness of the sediment after the first hole cleaning shall not be greater than 200mm, and the mud index shall meet the requirements; when cleaning the hole, the water level in the hole should be kept at about 0.5m below the casing;

[0126] After the hole is completed, the pile hole and the cavity are scanned and self-checked with a caliper to measure whether the pile hole and the cavity meet the following requirements: the hole diameter is not less than the designed pile diameter, the hole inclination is allowed to have a deviation of 1%, the sediment thickness at the bottom of the hole is allowed to be ≤200, the diameter is allowed to have a deviation of -50mm, the cavity elevation is allowed to have a deviation of ±100mm, and the cavity height is allowed to have a deviation of -100mm; after the hole is completed and the cavity is tested, the second hole cleaning is carried out;

[0127] The second hole cleaning is done by slurry replacement method. When cleaning the hole, the water level in the hole should be kept at about 0.5m below the casing.

[0128] The pile hole formed in this embodiment is more accurately positioned, and the disc cavity can be accurately located at the center of the cement-soil composite consolidation body, so that the subsequently cast pile body can be better combined with the cement-soil composite consolidation body.

[0129] The specific construction process includes the following parts (1) to (6):

[0130] (1) Measurement and layout

[0131] Verify the coordinates of the pile positions of the bridge, confirm the pile position data provided by the design drawings, and have the surveyors use the total station to conduct on-site stakeout of the pile positions (coordinate method) and lay out the positions of the bored piles. Drive in wooden piles no shorter than 30 cm, nail steel nails on them, and make clear marks, measure the elevation of the working surface, and determine the depth of the pile driving. After the pile position is determined, use the crosshairs to lay out four guard piles, and use the four guard piles as the basis for burying the casing. After the casing is buried, use the total station to re-measure the pile position and verify the accuracy of the construction pile position and guard piles.

[0132] (2) Steel casing production and burial

[0133] The casing is made of steel, and is made of 8mm thick steel plate with a height of 3 meters. 5mm thick and 15cm high reinforcement rings are welded on the top, middle and bottom. The joints of the casing steel plate are welded densely and full. The inner wall of the welded joint should be smooth without protrusions and no water leakage. A 20cm×20cm overflow port is opened on the top of the casing. The inner diameter of the casing is 30cm larger than the pile diameter, and the buried depth of the casing is 2.7m; the plane position deviation between the center of the casing and the center of the pile is not more than 5cm, the vertical inclination is not more than 1%, and the top of the steel casing is 0.3m higher than the original ground. The casing is positioned by digging a pit, and clay soil is backfilled and compacted in layers at the bottom and around the outside of the casing to prevent leakage at the bottom of the casing.

[0134] (3) Drilling rig in place

[0135] Before placing the drilling rig, tamp the ground around the pile hole to ensure that the drilling rig is placed stably; lay out the lines according to the designed pile position, bury the casing, and fill clay around the casing; before drilling, the drilling rig should be leveled vertically and horizontally, and the guide sleeve should be installed. When the drilling rig is in place, ensure that the center of the drill bit and the center of the pile position are on the same plumb line, and the centering error is less than 10mm; after the drilling rig is in place, measure the elevation of the top of the casing. At the same time, fill in the inspection form, and only after the supervising engineer has checked and accepted the centering of the drilling rig and the verticality of the drill rod, can drilling be carried out. Before formal drilling, the drilling rig must first be tested for operation to check the stability and condition of the drilling rig to ensure that the subsequent hole construction can be carried out continuously.

[0136] (4) Drilling

[0137] The rotary drilling rig uses a barrel-type drill bucket. After the drilling rig is in place, adjust the verticality of the drill rod, inject the prepared mud, and then drill. When the drill bit drops to the predetermined depth, rotate the drill bucket and apply pressure to squeeze the soil into the drill bucket. When the instrument automatically shows that the barrel is full, the bottom of the drill bucket is closed, and the drill bucket is lifted to unload the soil to the stacking location. During the drilling rig construction process, ensure that the mud surface is never lower than the bottom of the casing to ensure the stability of the hole wall. Through the rotation of the drill bucket, soil cutting, lifting, unloading soil and mud supporting the hole wall, the cycle is repeated until the hole is formed.

[0138] (5) Pile hole and disc cavity forming

[0139] Before drilling, the vertical distance between the maximum diameter position of the rotary cutter drill bit after it is opened and the drill bit collar (drilling and expansion machine drill bit) or the bottom of the rotary cutter drill bit (rotary cutter drill bit of a rotary drilling rig) should be measured. When drilling to a certain position, the distance should be exceeded.

[0140] The drilling rig first drills a hole, drills to the first disk position, and carries out disk expansion construction. After the disk diameter at the disk end meets the design requirements as shown by the disk expansion indicator, drilling continues, and drilling and expansion are carried out alternately.

[0141] The drilling depth reaches the depth specified in the drawing, and the slag is cleared by the drilling rig. The thickness of the sediment after the hole cleaning shall not be greater than 200mm, and the mud index shall meet the requirements. When cleaning the hole, the water level in the hole should be kept at about 0.5m below the casing to prevent the hole from collapsing.

[0142] (6) Hole forming and cavity detection

[0143] After the consolidation and expansion pile is completed, the pile hole and the disc cavity are scanned and self-inspected with a caliper. The inspection items include: hole depth, hole diameter, disc position, disc cavity diameter and disc cavity height.

[0144] After drilling and cavity inspection, the data should be reported to the supervisor in a timely manner, and the next construction process can only be carried out if it meets the inspection and evaluation standards.

[0145]

[0146] (7) Clearing the hole

[0147] The hole is cleaned by slurry replacement method. When cleaning the hole, pay attention to maintaining the water level in the hole to prevent hole collapse.

[0148] The purpose of hole cleaning is to remove drilling slag and sediment layer, minimize the thickness of sediment at the bottom of the hole, and prevent excessive sediment from remaining at the bottom of the pile and reducing the integrity of the pile body. Hole cleaning is carried out twice. The first hole cleaning is carried out after the drilling depth reaches the designed depth. The first hole cleaning should meet the requirements of the specification, otherwise the steel cage should not be lowered.

[0149] Thickness detection of sedimentation layer: a steel plate with a length of 12cm × width of 12cm × thickness of 1cm is made on site, a lifting ring is welded in the middle of the steel plate, and the lifting ring is connected to the measuring rope for measurement. Experienced staff on site use the steel plate to measure the distance H1 to the surface of the sedimentation layer at the bottom of the pile, and then use Ф25 steel bars to make a vertical tool with a length of 15cm, which is lowered to the bottom of the sedimentation layer to measure the distance H2. The thickness of the sedimentation layer is the difference between the two distance measurements, that is: H=H2-H1.

[0150] After the steel cage is hoisted in and before the underwater concrete is poured, the performance index of the mud in the hole and the thickness of the sediment at the bottom of the hole should be checked again. If they do not meet the requirements, the hole should be cleaned for the second time. The hole cleaning before pouring concrete must meet the following standards:

[0151] After hole cleaning, the relative density of the mud should be controlled at 1.03-1.10, the viscosity should be 17-20 Pa·s, the sand content should be less than 2%, and the colloid content should be greater than 98%. The thickness of the bottom sediment should not exceed the design requirements; it is strictly forbidden to use the method of deepening the drilling depth instead of hole cleaning.

[0152] See also Figures 4 to 10The embodiment of the present application also provides a high-pressure rotary jet pile machine, which includes: a consolidation and expansion pile construction process applicable to any of the above items; the high-pressure rotary jet pile machine includes a main machine and a drill rod, and the drill rod includes:

[0153] The outer casing has a cement nozzle, a water nozzle and an air nozzle on the side wall of one end where the drill bit is installed;

[0154] An inner sleeve is coaxially sleeved inside the outer sleeve; a cylindrical gap between the inner sleeve and the outer sleeve forms a cement slurry cavity, and the cement slurry cavity is connected to the cement nozzle; and

[0155] The inner second sleeve is coaxially sleeved inside the inner first sleeve; the cylindrical gap between the inner second sleeve and the inner first sleeve forms a water flow cavity, which is connected to the water flow nozzle through the inner first connecting pipe; the inner second sleeve forms an air flow cavity, which is connected to the air flow nozzle through the inner second connecting pipe;

[0156] Among them, cement nozzles include:

[0157] A round seat having a through injection hole; the round seat is embedded in a circular cavity on the side wall of the outer casing, and the outer end of the injection hole faces the outside of the outer casing, and the inner end is connected to the cement slurry cavity; the round seat can swing along the axial plane of the outer casing, and the outer end of the injection hole changes the injection angle through the swing of the round seat; and

[0158] The driving structure includes a gear and a rack; the gear is connected to the round seat; the rack is meshed with the gear to drive the round seat to swing through the gear; and

[0159] The high-pressure rotary jet pile driver also includes a first control structure, which includes a first push-up cam and a first push rod; the first push-up cam is arranged at the top of the drill rod and is fixedly arranged; the first push rod is arranged on the inner wall of the outer casing and is slidably arranged along the axial direction, and one end is driven by the first push-up cam and the other end drives the rack;

[0160] During the rotation of the drill rod, the first push cam drives the first push rod to move axially back and forth; when the drill rod rotates to the point where the cement nozzle faces inward, the first push rod drives the round seat to rotate through the rack and gear until the injection hole is tilted downward or upward; when the drill rod rotates to the point where the cement nozzle faces outward, the first push rod drives the round seat to rotate through the rack and gear until the injection hole faces horizontally outward.

[0161] Compared with the prior art, the high-pressure jet grouting pile machine of the embodiment of the present application, when the drill rod is drilled into the ground to perform jet grouting of cement-soil composite monomers, when the drill rod is rotated to the point where the cement nozzle faces inward (the side close to the main pile position), the first control structure drives the driving structure to rotate the round seat to the point where the injection hole is tilted downward or upward, so that the injected cement diffuses less toward the main pile position, reducing the difficulty of drilling and expanding the main pile position in the later stage, improving the construction efficiency, and also reducing the excessive removal of cement poured in the early stage, thereby reducing waste;

[0162] Moreover, the use of downward or upward deflected spraying through the spray hole can not reduce the amount of cement sprayed, compared with the conventional closed spray hole method, so that a large amount of cement can be diffused to the surrounding under pressure, so that the cement-soil composite monomers adjacent to the same predetermined elevation position are more closely connected together;

[0163] When the drill rod rotates to the side where the cement nozzle faces outward (away from the main pile position), the first control structure drives the driving structure to rotate the round seat to the side where the injection hole faces outward horizontally, thereby causing the injected cement to spread farther to the outside away from the main pile position, thereby increasing the outer diameter of the formed cement-soil composite consolidation body.

[0164] In the specific implementation, the main machine is mainly used to erect the drill rod and control the drill rod to perform drilling operations, and also provides the drill rod with high-pressure cement, high-pressure water, and high-pressure air required for grouting. The specific structure of the main machine can refer to the common jet grouting machine on the market, and will not be repeated here.

[0165] The outer casing, the inner casing and the second inner casing are coaxially sleeved together in sequence to form a drill pipe. The upper end of the drill pipe is rotatably connected to the main machine, and the drill bit is installed at the lower end. At the position near the drill bit at the lower end of the drill pipe, the outermost outer casing is provided with three types of nozzles: cement nozzle, water nozzle and air nozzle. The number and position of various nozzles can refer to the common rotary grouting pile machine on the market, and can also be adjusted according to the actual needs of the project. The cement nozzle is directly connected to the cement slurry cavity, the water nozzle is connected to the water cavity through the inner first connecting pipe running through the inner casing, and the air nozzle is connected to the air cavity through the inner second connecting pipe running through the inner casing and the second inner casing.

[0166] The round seat of the cement nozzle is disc-shaped and has injection holes along the diameter. The round seat is embedded in the circular cavity on the side wall of the outer casing, which can flexibly adjust the direction of the injection hole and prevent gaps from forming when the round seat rotates a certain angle, thus preventing cement slurry from leaking. In a specific implementation, the inner end of the injection hole can be a bell mouth, which is conducive to the entry of cement slurry.

[0167] The round seat can be partially protruded from the outer wall of the outer casing, so that when the round seat rotates, the outer end of the injection hole will not be blocked by the outer wall of the outer casing. Usually, the protruding height of the round seat does not exceed the circumscribed circle of the drill bit to reduce the friction between the protruding part of the round seat and the hole wall. In addition, baffles can be welded on the outer wall of the outer casing, and the baffles are respectively located on the upper and lower sides and the left and right sides of the round seat, which can reduce the friction of the surrounding soil layer on the protruding part of the round seat when drilling.

[0168] The gear of the driving structure is fixed on the rotating shaft of the round seat to drive the round seat to rotate. A mounting groove is provided on the inner wall of the outer sleeve, and the rack is slidably installed in the mounting groove to cooperate with the gear. An axial guide groove is also provided on the inner wall of the outer sleeve, the lower end of which is connected to the mounting groove of the rack and the upper end passes through the outer sleeve; the first push rod of the first control structure is slidably installed in the guide groove, and the lower end is fixedly connected to the rack, and the upper end passes through the outer sleeve along the guide groove to cooperate with the first push cam.

[0169] The first push cam of the first control structure can be connected to the main machine part so as to remain fixed and not rotate with the drill rod. When the drill rod rotates, the first push rod rotates with the drill rod, so that the first push rod moves along the first push cam and is driven by the first push cam according to the cam curve, thereby driving the rack to slide up and down.

[0170] The cam curve of the first push cam is designed as follows: during the process of the drill rod rotating one circle, when the drill rod is turned to an angle where the cement nozzle faces inward, the first push rod pushes the rack downward to make the injection hole of the round seat deflect upward, or the first push rod pulls the rack upward to make the injection hole of the round seat deflect downward; when the drill rod is turned to an angle where the cement nozzle faces outward, the first push rod drives the rack to make the injection hole of the round seat horizontal. The cam curve of the first push cam has a smooth transition to reduce the jamming of the first push rod.

[0171] See also Figure 4 and Figure 5 The embodiment of the present application also provides a high-pressure rotary jet pile driver, wherein a first rotary joint connected to an outer casing is provided at the top of the drill rod; the first push-up cam is a cylindrical cam sleeved on the top of the outer casing, and the first push-up cam is fixed by the first rotary joint;

[0172] The upper end of the first push rod passes through the outer sleeve and is provided with a roller embedded in the cam groove of the first push cam.

[0173] In this embodiment, the first rotary joint is mainly used to connect the high-pressure cement pipe on the main machine with the rotating cement slurry chamber, and its main structure can refer to the rotary pipe joint structure commonly used in the rotary grouting pile driver on the market.

[0174] In a specific implementation, the first push cam is fixed to the first rotary joint so as not to rotate with the drill rod. A cam groove is provided on the outer wall of the first push cam, and the roller at the upper end of the first push rod rolls along the cam groove, so that the up and down movement of the first push rod can be controlled by controlling the curve of the cam groove.

[0175] See also Figure 7 and Figure 8 The embodiment of the present application also provides a high-pressure rotary jet pile driver, wherein the inner sleeve also includes:

[0176] A first blocking plate is disposed on the inner wall of the inner sleeve and is slidably disposed along the axial direction to block or open an inner connecting tube;

[0177] The second control structure includes a second push cam and a second push rod; the second push cam is arranged at the top of the drill pipe and is fixed; the second push rod is arranged on the inner wall of the inner sleeve and is slidably arranged along the axial direction, and one end of the second push cam is driven by the second push cam, and the other end drives the first blocking plate;

[0178] During the rotation of the drill rod, the second push cam drives the second push rod to move axially back and forth; when the drill rod rotates to the point where the cement nozzle faces inward, the second push rod drives the first blocking plate to at least partially cover the inner connecting tube; when the drill rod rotates to the point where the cement nozzle faces outward, the second push rod drives the first blocking plate to open the inner connecting tube.

[0179] In practice, a slide groove is provided on the inner wall of the inner sleeve at the position where the inner connecting pipe is connected, and the first blocking plate is axially slidable up and down in the slide groove, so that the inner connecting pipe can be blocked or opened by sliding the first blocking plate.

[0180] An axial guide groove is also provided on the inner wall of the inner sleeve, the lower end of the guide groove is connected to the slide groove of the first blocking plate, and the upper end passes through the outside of the inner sleeve; the second push rod of the second control structure is slidably arranged in the guide groove, and the lower end is fixedly connected to the first blocking plate, and the upper end passes through the outside of the inner sleeve along the guide groove to cooperate with the second push cam.

[0181] The second push cam of the second control structure can be connected to the main machine part so as to remain fixed and not rotate with the drill rod. When the drill rod rotates, the second push rod rotates with the drill rod, so that the second push rod moves along the second push cam and is driven by the second push cam according to the cam curve, thereby driving the first blocking plate to slide up and down, covering or opening the inner connecting pipe.

[0182] The cam curve of the second push-up cam is designed as follows: during one rotation of the drill rod, when the drill rod is turned to an angle where the cement nozzle faces inward, the second push rod pushes the first blocking plate downward, so that the first blocking plate partially or completely blocks the inner connecting pipe, and the water nozzle reduces or stops spraying; when the drill rod is turned to an angle where the cement nozzle faces outward, the second push rod drives the first blocking plate to move upward, so that the inner connecting pipe is fully opened, and the water nozzle sprays normally. The cam curve of the second push-up cam has a smooth transition, which reduces the jamming of the second push rod.

[0183] See also Figure 4 and Figure 7 The embodiment of the present application also provides a high-pressure rotary jet pile driver, wherein a second rotary joint connected to an inner sleeve is provided at the top of the drill rod; the second push-out cam is a cylindrical cam sleeved on the top of the inner sleeve, and the second push-out cam is fixed by a second rotary joint;

[0184] The upper end of the second push rod passes through the inner sleeve and is provided with a roller embedded in the cam groove of the second push cam.

[0185] In a specific implementation, the second push cam is fixed to the second rotary joint so as not to rotate with the drill rod. A cam groove is provided on the outer wall of the second push cam, and the roller at the upper end of the second push rod rolls along the cam groove, so that the up and down movement of the second push rod can be controlled by controlling the curve of the cam groove.

[0186] See also Fig. 9 and Fig.10 The embodiment of the present application also provides a high-pressure rotary jet pile driver, wherein the inner second casing also includes:

[0187] A second blocking plate is disposed on the inner wall of the inner second sleeve and is slidably disposed along the axial direction to block or open the inner second connecting pipes;

[0188] The third control structure includes a third push cam and a third push rod; the third push cam is arranged at the top of the drill pipe and is fixed; the third push rod is arranged on the inner wall of the inner second casing and is slidably arranged along the axial direction, and one end of the third push rod is driven by the third push cam and the other end drives the second blocking plate;

[0189] During the rotation of the drill rod, the third push cam drives the third push rod to move axially back and forth; when the drill rod rotates to the point where the cement nozzle faces inward, the third push rod drives the second blocking plate to at least partially block the two inner connecting tubes; when the drill rod rotates to the point where the cement nozzle faces outward, the third push rod drives the second blocking plate to open the two inner connecting tubes.

[0190] In practice, a slide groove is provided on the inner wall of the inner second sleeve and at the position where the inner second connecting pipes are connected, and the second blocking plate is axially slidable up and down in the slide groove, so that the inner second connecting pipes can be blocked or opened by sliding the second blocking plate.

[0191] Two axial guide grooves are also provided on the inner wall of the inner two sleeves, the lower end of the guide groove is connected to the sliding groove of the second blocking plate, and the upper end passes through the outside of the inner two sleeves; the third push rod is slidably arranged in the guide groove, and the lower end is fixedly connected to the second blocking plate, and the upper end passes through the outside of the inner two sleeves along the guide groove to cooperate with the third push cam.

[0192] The third push cam of the third control structure can be connected to the main machine part so as to remain fixed and not rotate with the drill rod. When the drill rod rotates, the third push rod rotates with the drill rod, so that the third push rod moves along the third push cam and is driven by the third push cam according to the cam curve, thereby driving the second blocking plate to slide up and down, covering or opening the inner two connecting pipes.

[0193] The cam curve of the third push-up cam is designed as follows: during one rotation of the drill rod, when the drill rod is turned to an angle where the cement nozzle faces inward, the third push rod pushes the second blocking plate downward, so that the second blocking plate partially or completely blocks the second inner connecting pipe, and the airflow nozzle reduces or stops spraying; when the drill rod is turned to an angle where the cement nozzle faces outward, the third push rod drives the second blocking plate to move upward, so that the second inner connecting pipe is fully opened, and the airflow nozzle sprays normally. The cam curve of the third push-up cam has a smooth transition, which reduces the jamming of the third push rod.

[0194] See also Figure 4 and Fig. 9 The embodiment of the present application also provides a high-pressure rotary jet pile driver, wherein a third rotary joint connected to the inner second casing is provided at the top of the drill rod; the third push-up cam is a cylindrical cam sleeved on the top of the inner second casing, and the third push-up cam is fixed by a third rotary joint;

[0195] The upper end of the third push rod passes through the outside of the inner two sleeves and is provided with a roller embedded in the cam groove of the third push cam.

[0196] In a specific implementation, the third push cam is fixed to the third rotary joint so as not to rotate with the drill rod. A cam groove is provided on the outer wall of the third push cam, and the roller at the upper end of the third push rod rolls along the cam groove, so that the up and down movement of the third push rod can be controlled by controlling the curve of the cam groove.

[0197] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A high-pressure jet grouting machine suitable for the construction process of consolidation and expansion piles, characterized in that: include: The high-pressure jet pile driver comprises a main machine and a drill rod, wherein the drill rod comprises: The outer casing has a cement nozzle, a water nozzle and an air nozzle on the side wall of one end where the drill bit is installed; An inner sleeve is coaxially sleeved inside the outer sleeve; a cylindrical gap between the inner sleeve and the outer sleeve forms a cement slurry cavity, and the cement slurry cavity is connected to the cement nozzle; and The inner second sleeve is coaxially sleeved inside the inner one sleeve; the cylindrical gap between the inner second sleeve and the inner one sleeve forms a water flow cavity, and the water flow cavity is connected with the water flow nozzle through an inner connecting pipe; the inner second sleeve forms an air flow cavity, and the air flow cavity is connected with the air flow nozzle through the inner second connecting pipe; Wherein, the cement nozzle comprises: A round seat having a through injection hole; the round seat is embedded in a circular cavity on the side wall of the outer casing, and the outer end of the injection hole faces the outside of the outer casing, and the inner end is connected to the cement slurry cavity; the round seat can swing along the axial plane of the outer casing, and the outer end of the injection hole changes the injection angle through the swing of the round seat; and A driving structure, comprising a gear and a rack; the gear is connected to the round seat; the rack is meshed with the gear to drive the round seat to swing through the gear; and The high-pressure rotary jet pile driver also includes a first control structure, which includes a first push-up cam and a first push rod; the first push-up cam is arranged at the top of the drill rod and is fixedly arranged; the first push rod is arranged on the inner wall of the outer casing and is slidably arranged along the axial direction, and one end is driven by the first push-up cam and the other end drives the rack; During the rotation of the drill rod, the first push cam drives the first push rod to reciprocate axially; when the drill rod rotates until the cement nozzle faces inward, the first push rod drives the round seat to rotate through the rack and gear until the injection hole is deflected downward or upward; when the drill rod rotates until the cement nozzle faces outward, the first push rod drives the round seat to rotate through the rack and gear until the injection hole is horizontally outward; The top of the drill pipe is provided with a first rotary joint connected to the outer casing; the first push-out cam is a cylindrical cam sleeved on the top of the outer casing, and the first push-out cam is fixed by the first rotary joint; The upper end of the first push rod passes through the outer sleeve and is provided with a roller embedded in the cam groove of the first push cam; The consolidation and expansion pile construction process comprises: The cement-soil composite consolidation body is constructed by using a high-pressure rotary jet pile machine to perform multiple drilling operations around the main pile position; during each drilling operation, grouting is sprayed from bottom to top at multiple predetermined elevation positions to form cement-soil composite monomers; the cement-soil composite monomers formed at the same predetermined elevation position in each drilling operation are connected to form a cement-soil composite consolidation body; Pile hole construction: using a rotary drilling rig to rotary drill pile holes at the main pile position, and forming a disc cavity with an enlarged diameter on each cement-soil composite consolidation body; During the steel cage installation construction, the steel cage will be lowered into the pile hole; Underwater concrete pouring, pouring concrete into the pile hole from bottom to top through a conduit to form the pile body.

2. The high-pressure jet grouting machine suitable for the consolidation and expansion pile construction process according to claim 1, characterized in that: The inner sleeve also includes: A first blocking plate is disposed on the inner wall of the inner sleeve and is slidably disposed along the axial direction to block or open the inner connecting tube; The second control structure comprises a second push cam and a second push rod; the second push cam is arranged at the top of the drill rod and is fixedly arranged; the second push rod is arranged on the inner wall of the inner sleeve and is slidably arranged along the axial direction, and one end of the second push cam drives the first blocking plate, and the other end drives the first blocking plate; During the rotation of the drill rod, the second push cam drives the second push rod to move axially back and forth; when the drill rod is rotated to the point where the cement nozzle faces inward, the second push rod drives the first blocking plate to at least partially cover the inner connecting tube; when the drill rod is rotated to the point where the cement nozzle faces outward, the second push rod drives the first blocking plate to open the inner connecting tube.

3. The high-pressure jet grouting machine suitable for the consolidation and expansion pile construction process as claimed in claim 2, characterized in that: The top of the drill pipe is provided with a second rotary joint connected to the inner sleeve; the second push-out cam is a cylindrical cam sleeved on the top of the inner sleeve, and the second push-out cam is fixed by the second rotary joint; The upper end of the second push rod passes through the outside of the inner sleeve and is provided with a roller embedded in the cam groove of the second push cam.

4. The high-pressure jet grouting pile machine suitable for the consolidation and expansion pile construction process according to claim 1, characterized in that: The inner second sleeve also includes: A second blocking plate is provided on the inner wall of the inner second sleeve and is slidably arranged along the axial direction to block or open the inner second connecting pipe; The third control structure comprises a third push cam and a third push rod; the third push cam is arranged at the top of the drill rod and is fixed; the third push rod is arranged on the inner wall of the inner second casing and is slidably arranged along the axial direction, and one end is driven by the third push cam and the other end drives the second blocking plate; During the rotation of the drill rod, the third push cam drives the third push rod to move axially back and forth; when the drill rod rotates to the point where the cement nozzle faces inward, the third push rod drives the second blocking plate to at least partially cover the two inner connecting tubes; when the drill rod rotates to the point where the cement nozzle faces outward, the third push rod drives the second blocking plate to open the two inner connecting tubes.

5. The high-pressure jet grouting pile machine suitable for the consolidation and expansion pile construction process as claimed in claim 4, characterized in that: The top of the drill pipe is provided with a third rotating joint connected to the inner second casing; the third ejection cam is a cylindrical cam sleeved on the top of the inner second casing, and the third ejection cam is fixed by the third rotating joint; The upper end of the third push rod passes through the outside of the inner second sleeve and is provided with a roller embedded in the cam groove of the third push cam.

6. The high-pressure jet grouting machine suitable for the consolidation and expansion pile construction process according to claim 1, characterized in that: In the cement-soil composite consolidation body construction step, a double ultra-high pressure triple pipe method is used for construction; In the construction of a single cement-soil composite consolidation body, cement is P.O42.5 ordinary Portland cement, and the water-cement ratio of cement slurry is 1.0; during grouting, the drill rod lifting speed is 5~20cm / min, the drill rod rotation speed is 18~25r / min, the pressure of the high-pressure cement slurry jet is 36~40MPa, the cement slurry flow rate is 220~240L / min, the air flow pressure is 1.3MPa, and the gas flow rate is 5~8m 3 / min; During the construction of a single cement-soil composite consolidation body, the high-pressure rotary jet pile driver drills to the specified elevation and then performs jet grouting. The jet grouting should adopt the above-mentioned parameters and be carried out from bottom to top according to the triple pipe method construction process.

7. The high-pressure jet grouting pile machine suitable for the consolidation and expansion pile construction process according to claim 1, characterized in that: In the cement-soil composite consolidation body construction steps, each time a hole is drilled, the verticality of the drill rod must be controlled within 0.2 degrees, the center of the guide frame of the drill rod should be consistent with the center of the power head, and the deviation between the drilling position and the designed pile position must not exceed 50 mm.

8. The high-pressure jet grouting pile machine suitable for the consolidation and expansion pile construction process according to claim 1, characterized in that: The pile hole construction steps include: Measure and stake out, confirm the main pile position data, use the total station to stake out the main pile position on the spot through the coordinate method, and stake out the secondary pile position; The casing is buried and positioned by digging a pit, and the bottom and the outer sides of the casing are backfilled with clay soil and compacted in layers; the inner diameter of the casing is 30cm larger than the pile diameter, the buried depth of the casing is 2.7m, the plane position deviation between the center of the casing and the center of the main pile position is not more than 5cm, the vertical inclination is not more than 1%, and the top of the casing is 0.3m higher than the original ground; The pile hole and the plate cavity are formed. The drilling rig first drills the hole, and after drilling to the cement-soil composite consolidation body at the predetermined elevation, the plate expansion construction is carried out. The drilling construction and the plate expansion construction are carried out alternately until the predetermined depth is reached; The first hole cleaning is to use a drilling rig to clean the slag. The thickness of the sediment after the first hole cleaning shall not be greater than 200mm, and the mud index shall meet the requirements; when cleaning the hole, the water level in the hole shall be maintained at 0.5m below the casing; After the hole is completed, the pile hole and the cavity are scanned and self-checked with a caliper to measure whether the pile hole and the cavity meet the following requirements: the hole diameter is not less than the designed pile diameter, the hole inclination is allowed to have a deviation of 1%, the sediment thickness at the bottom of the hole is allowed to be ≤200, the diameter is allowed to have a deviation of -50mm, the cavity elevation is allowed to have a deviation of ±100mm, and the cavity height is allowed to have a deviation of -100mm; after the hole is completed and the cavity is tested, the second hole cleaning is carried out; The second hole cleaning is done by slurry replacement method. When cleaning the hole, the water level in the hole should be maintained at 0.5m below the casing.

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