Device and method for improving pulling resistance of large-diameter non-soil-squeezing tubular pile

Abstract

The invention discloses a device and method for improving the anti-pulling performance of a large-diameter non-soil-squeezing pipe pile. The device comprises a pipe pile, the pipe pile sinks to a set elevation, a core drilling machine drills an inclined hole into a rock stratum along an inner cavity of the pipe pile, a reinforcement cage is arranged in the inclined hole, and a grouting pipe is used for injecting steel fiber concrete into the inner cavity of the pipe pile. Two high-pressure grouting pipes are pre-buried in designed reserved positions on the two sides in the pipe pile, and high-pressure nozzles are arranged at the lower ends of the high-pressure grouting pipes; the concrete mixing tank is used for injecting steel fiber concrete, one end of the concrete mixing tank is in pipeline connection with the high-pressure rotary jet grouting machine, and the high-pressure rotary jet grouting machine is in pipeline connection with the high-pressure grouting pipe; a groove is formed in the side wall, located at the soft soil layer, of the pipe pile, a bag is embedded in the groove, and sawteeth are arranged on the surface of the bag. Compared with the prior art, the method has the advantages that the uplift performance of the uplift pile is comprehensively improved through four measures for improving the uplift resistance of the pile on the pile bottom rock-socketed layer, the aquifer, the hard soil layer and the soft soil layer.

Description

Technical Field

[0001] The present invention relates to the technical field of pile foundation engineering, and specifically to a device and method for improving the uplift performance of large-diameter non-displacement pipe piles. Background Art

[0002] As a key foundation engineering technology means, the main purpose of uplift piles is to effectively resist the uplift forces borne by buildings or structures, and they are widely used in the anti-floating of large basements, the uplift resistance of high-rise buildings, the uplift resistance of offshore wharf platforms, the anchor pile foundations of suspension bridges and cable-stayed bridges, the pile foundations of large dock floors, etc. In modern urban construction, the construction of large basements is common. Since basements often have a large area and depth, when the groundwater level is high, the huge buoyancy generated by groundwater will exert an uplift effect on the basement structure. High-rise buildings such as skyscrapers and TV towers not only bear their own huge vertical gravity loads, but may also be affected by horizontal loads such as wind forces and seismic forces. In some cases, these horizontal loads will generate upward components, forming uplift forces. Offshore wharf platforms are in a marine environment and not only have to bear the vertical loads from the superstructure, but also have to cope with the periodic uplift forces caused by the ebb and flow of seawater tides and the additional uplift forces caused by wave impacts. For large bridge projects such as suspension bridges and cable-stayed bridges, the anchor pile foundation, as a key component, bears huge tensile forces. The main cable of a suspension bridge transmits the tensile force to the anchor pile through the anchor block, and the stay cables of a cable-stayed bridge also exert a strong uplift force on the tower foundation. In the construction of large shipyards, the dock floor needs to bear various complex loads such as the weight of ships in the dock, water pressure, and possible buoyancy. Uplift piles play an indispensable role in the above fields and can effectively resist these uplift forces, thus ensuring the stability and safety of these buildings and structures in a complex stress environment. In the prior art, relying on the on-site construction method of follow-the-drill pipe piles, if PHC pipe piles are constructed using the hammering method or the jacking method, their diameters are usually less than 600 mm and it is difficult for the pile bottom to be embedded in hard rock soil layers. Therefore, the bearing capacity of a single pile is difficult to meet the design requirements. For large-diameter pipe piles, their end resistance and side resistance are both large, making it difficult to sink the piles, and it is easy to cause pile body damage or pipe pile deviation during construction. Therefore, generally, the method of bored cast-in-place piles is adopted to construct large-diameter pipe piles, but when constructing large-diameter pipe piles by bored cast-in-place piles, there are disadvantages such as difficult control of pile body quality, low construction efficiency, mud pollution of the environment, high cost, and difficult control of pile position deviation.

[0003] The information disclosed in this background art section is only intended to increase the understanding of the overall background of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art already known to those of ordinary skill in the art. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a device and method for improving the pull-out resistance of large-diameter non-squeezing pipe piles.

[0005] In order to solve the above problems, the technical solution of the present invention is: a device for improving the pull-out resistance of large-diameter non-squeezing soil pipe piles, comprising pipe piles, rock formations, a drilling coring machine, a steel cage, a concrete pump truck, steel fiber concrete, a cover plate, a vacuum pump, a drainage pipe, a water storage tank, and a concrete mixing tank; The upper end of the rock layer is provided with an aquifer, a hard soil layer and a soft soil layer in sequence; The pipe pile is sunk to a set elevation, the core drilling machine drills an inclined hole into the rock formation along the inner cavity of the pipe pile, the steel cage is arranged inside the inclined hole, a concrete delivery pump is arranged at one end of the concrete pump truck, a grouting pipe is connected to the other end of the concrete delivery pump, the grouting pipe is used to inject steel fiber concrete into the inner cavity of the pile, a plurality of first coarse-grained concrete drainage holes are arranged on the side of the pipe pile, a cover plate is arranged on the top of the inner cavity of the pipe pile, a high-pressure pipe is arranged inside the pipe pile, the upper end of the high-pressure pipe is connected to a vacuum pump, a pipe at one end of the vacuum pump is connected to a water tank, and a water outlet is arranged at the other end of the water tank; A second coarse-grained concrete drainage hole is provided inside the pipe pile, a drainage pipe is provided inside the pipe pile, and the upper end of the drainage pipe is connected to a vacuum pump; Two high-pressure grouting pipes are pre-buried at the designed reserved positions on both sides of the pipe pile, and a high-pressure nozzle is provided at the lower end of the high-pressure grouting pipe; The concrete mixing tank is used to inject steel fiber concrete, and a pipeline at one end of the concrete mixing tank is connected to a high-pressure rotary jet grouting machine, and the pipeline of the high-pressure rotary jet grouting machine is connected to a high-pressure grouting pipe; A groove is arranged on the side wall of the pipe pile located at the soft soil layer, a bag is inlaid on the groove, and saw teeth are arranged on the surface of the bag.

[0006] Furthermore, a pile shoe is provided at the bottom of the pipe pile, and pile clamps are provided on both sides of the upper part of the pipe pile, and the pile shoe is about 2m below the rock layer.

[0007] Furthermore, the high-pressure pipe is provided with a pressure gauge and a plurality of control valves.

[0008] The present application also includes a large diameter non-squeezing soil anti-pullout pile construction method, comprising the following steps: Step 1: embed the rock layer at the bottom of the pipe pile, use a core drilling machine to drill inclined holes along the inner cavity of the pipe pile to the rock layer, one inclined hole every 60 degrees, a total of six inclined holes in one pipe pile position, the inclined holes are used to place the steel cage later, after drilling the inclined holes, the sediment in the holes needs to be cleaned up, so that the steel cage can be accurately placed in the inclined holes later, and the steel fiber concrete can be more evenly and completely wrapped when sealing the bottom; after placing the steel cage, a prestress needs to be applied to the steel cage, the umbrella-shaped barbs of the steel cage are opened, and the barbs are inserted into the soil to improve The pull-out resistance of the pile is then tested by injecting steel fiber concrete into the pile cavity with a concrete pump truck to seal the bottom. When sealing the bottom, first use a concrete pump to inject steel fiber concrete into the steel cage at the bottom of the pipe pile, then use a vibrating rod to extend into the steel cage to vibrate the steel fiber concrete to ensure that the steel fiber concrete at the steel cage in the inclined hole is uniform, and then inject steel fiber concrete into the bottom of the pipe pile and vibrate it evenly. The bottom of the pipe pile is embedded in the rock for about 0.5m. Finally, the pile driver is used to deliver the pipe pile to the top of the pipe pile to the designated elevation position; Step 2: In the aquifer, determine the soil layer information and groundwater storage information based on the previous geological survey, design the number and position of the first coarse-grained concrete drainage holes of the pipe pile, and pour coarse-grained concrete at the designated position of the pipe pile. The water in the aquifer can enter and exit the inner cavity of the pipe pile through the first coarse-grained concrete drainage holes. Then install a cover plate on the top of the pipe pile. The cover plate on the top of the pipe pile and the steel fiber concrete embedded in the rock layer at the bottom of the pipe pile seal the inner cavity of the pipe pile. Apply positive pressure to the inner cavity of the pipe pile through a vacuum pump and a high-pressure pipe. A pressure gauge and multiple control valves are provided on the high-pressure pipe to prevent damage caused by excessive pressure in the pipeline. The water in the inner cavity is squeezed out to the aquifer through the first coarse-grained concrete drainage hole by pressure, and the water in the aquifer diffuses away from the pile periphery under the positive pressure of the inner cavity of the pipe pile, and then the pile side is grouted through the pre-buried grouting pipe in the pipe pile until the grouting is stopped after the upper end of the pipe pile emerges. After the pile side grouting is completed, the first coarse-grained concrete drainage hole needs to be taken out, and the grouting liquid is chiseled at the corresponding position of the first coarse-grained concrete drainage hole to the position of the aquifer, and the second coarse-grained concrete drainage hole is put in. The second coarse-grained concrete drainage hole connects the inner cavity of the pipe pile, the grouting liquid and the aquifer, and the water in the aquifer can enter and exit the inner cavity of the pipe pile through the second coarse-grained concrete drainage hole; Step 3: In the hard soil layer, determine the position and thickness of the hard soil layer through the preliminary geological survey. When prefabricating large-diameter pipe piles, embed two two-centimeter-thick high-pressure grouting pipes at the reserved positions on both sides of the pipe piles. Before construction, inject the steel fiber concrete into the concrete mixing tank through the concrete delivery pump of the concrete pump truck. Use a high-pressure rotary jet grouting machine to extract the steel fiber concrete in the concrete mixing tank, and spray the slurry into the hard soil layer through a high-pressure nozzle. Connect with the grouting liquid on the pile side as a whole to hook the hard soil layer; Step 4: Soft soil layer. According to the position of the pipe piles corresponding to the soft soil layer found in the previous geological survey, grooves are set around the side walls when prefabricating the pipe piles. Bags are embedded in the grooves. The surface of the bags is uneven and serrated. The grouting pipes embedded in advance are connected to the bags. When grouting on the pile side, grouting is injected into the bags through the pre-buried grouting pipes until grouting emerges from the pile end and then stops. After the construction is completed, the grouting effect of the bags needs to be tested, and the active soil pressure is tested by a micro soil pressure box to qualitatively check the grouting quality.

[0009] Furthermore, in step one, a steel cage with umbrella-shaped barbs is prefabricated in a steel processing workshop. The length of the steel cage is determined according to the pile length and the bearing layer at the bottom of the pile. The steel bars are cut and processed according to the design drawings and the size of the steel cage. The main bars and stirrups are connected into a steel cage by welding or binding. The weld quality must be ensured during welding, and the binding must be firm to prevent the steel cage from deforming during transportation and installation. The umbrella-shaped barbs are welded to the steel cage keel in a circle by welding. The top of the placed steel cage must be exposed in the inner cavity of the pipe pile to ensure that the center of the steel cage coincides with the center of the pile hole, and the verticality deviation of the steel cage does not exceed the allowable value of the specification.

[0010] Furthermore, in step two, the grouting pipe is made of steel and does not need to be taken out after the grouting is completed. It will not affect the strength of the pipe pile if it is pre-buried in the pipe pile. The grouting pipe is connected by welding. After the pile is connected, a water flow test is required to ensure that the grouting pipe is unobstructed. The first coarse-grained concrete is made of the same material as the second coarse-grained concrete. Negative pressure is applied to the inner cavity of the pipe pile through a vacuum pump and a high-pressure pipe, and water from the aquifer around the pipe pile is sucked into the inner cavity of the pipe pile through the negative pressure. Then, the water is pumped into the water tank through the drainage pipe in the inner cavity of the pipe pile. A water outlet is set at the back of the water tank, so that the water in the water tank can be used in other places in the construction project, saving water.

[0011] Furthermore, in step three, the high-pressure grouting pipe is made of steel, and the high-pressure nozzle is inclined upward at 45° to leak out of the pile. Multiple high-pressure grouting nozzles can be set according to needs. The high-pressure rotary jet grouting machine includes an air compressor and a high-pressure pump. The air compressor is used to increase the pressure and adjust the injection pressure, injection flow rate and lifting speed parameters. The pressure of high-pressure jet grouting is 20-40MPa, the air pressure is 0.7-0.8MPa, the slurry flow rate is 80-120L / min, and the lifting speed is 10-25cm / min. The high-pressure rotary jet grouting machine is equipped with a high-pressure gauge to monitor the pressure changes in real time during the grouting process to ensure pressure stability.

[0012] The advantages of the present invention compared with the prior art are: The present invention provides four measures for improving the pull-out resistance of the pile in the rock layer, aquifer, hard soil layer and soft soil layer at the bottom of the pile, which comprehensively improve the pull-out resistance of the pull-out pile; The pile bottom is embedded in the rock layer. By setting a circle of open steel cage at the bottom of the pipe pile, and sealing the bottom with steel fiber concrete to connect it with the pile bottom as a whole, the mechanical bite force and bonding force between the pile body and the foundation soil at the bottom of the pile can be enhanced, and the load can be better transferred to the deep solid rock layer to improve the pull-out resistance of the pile; In aquifers, the pull-out resistance of piles can be improved by draining water around the piles, lowering the groundwater level and reducing buoyancy. In the hard soil layer, the steel fiber concrete slurry is sprayed into the hard soil layer by a high-pressure rotary jet grouting machine to connect with the pile side grouting liquid as a whole to hook the hard soil layer soil and increase the pull-out resistance of the pile; In soft soil layers, by setting a serrated bag on the pile wall and injecting grout into the bag on the side of the pile, the bag expands to exert confining pressure on the pile body, forming a hoop-like effect, which can constrain the pile body and increase the lateral bearing capacity of the pile to improve the pull-out resistance of the pile. In engineering applications, comprehensive consideration of economic benefits and based on the underground soil geological conditions ascertained by geological surveys can be used to select one or more of the above four measures as the most effective and economical measures; BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0014] Figure 2 This is a schematic diagram of the rock formation construction of the present invention. Figure 1 .

[0015] Figure 3 This is a schematic diagram of the rock formation construction of the present invention. Figure 2 .

[0016] Figure 4 This is a schematic diagram of the rock formation construction of the present invention. Figure 3 .

[0017] Figure 5 This is a schematic diagram of the rock formation construction of the present invention. Figure 4 .

[0018] Figure 6 This is a schematic diagram of the aquifer construction of the present invention. Figure 1 .

[0019] Figure 7 This is a schematic diagram of the aquifer construction of the present invention. Figure 2 .

[0020] Figure 8 This is a schematic diagram of the aquifer construction of the present invention. Figure 3 .

[0021] Figure 9 This is a schematic diagram of the hard soil layer construction of the present invention. Figure 1 .

[0022] Figure 10 Schematic diagram of the construction of the hard soil layer of the present invention Figure 2 .

[0023] Figure 11 Schematic diagram of the construction of the soft soil layer of the present invention Figure 1 .

[0024] Figure 12 Schematic diagram of the construction of the soft soil layer of the present invention Figure 2 .

[0025] As shown in the figure: 1. Pipe pile; 2. Pile clamp; 3. Pile shoe; 4. Rock stratum; 5. Core drilling machine; 6. Steel reinforcement cage; 7. Concrete pump truck; 8. Concrete conveying pump; 9. Steel fiber concrete; 10. Aquifer; 11. First coarse-grained concrete drainage hole; 12. Cover plate; 13. Vacuum pump; 14. High-pressure pipe; 15. Pressure gauge; 16. Control valve; 17. Grouting pipe; 19. Second coarse-grained concrete drainage hole; 20. Drain pipe; 21. Water storage tank; 22. Water outlet; 23. Hard soil layer; 24. High-pressure grouting pipe; 25. High-pressure nozzle; 26. Concrete mixing pool; 27. High-pressure jet grouting machine; 28. Soft soil layer; 29. Pocket; 30. Sawtooth. Specific embodiments

[0026] The following will further illustrate the specific embodiments of the present invention with reference to the accompanying drawings. Among them, the same parts are denoted by the same reference numerals.

[0027] It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the accompanying drawings, and the terms "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component.

[0028] In order to make the content of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0029] As Figure 1 - shown, a construction method for a large-diameter non-excavated anti-pull pile includes the following steps: First, after the construction of drilling-sinking-pile discharging with the pipe pile following the drill is completed, the pipe pile 1 sinks to the set elevation, and the pile clamp 2 is used to clamp the pile to prevent the pile from falling. At this time, the drill bit drills more than 0.5 m below the rock stratum, the pile shoe 3 at the bottom of the pile is about 2 m below the rock stratum, the enlarged drill bit and the long spiral rod are pulled out, and the rotary bucket is used to clean the sediment at the bottom of the pile, and then the construction of the anti-pull pile starts.

[0030] Step 1: Embed the pipe pile 1 into the rock stratum 4 at the bottom. Use a core drilling machine 5 to drill inclined holes along the inner cavity of the pipe pile 1 towards the rock stratum 4. One inclined hole is drilled every 60°, and a total of six inclined holes are drilled at one pipe pile 1 position. These inclined holes are used to place the steel reinforcement cage 6 later. After drilling the inclined holes, the sediment in the holes needs to be cleaned up to facilitate the accurate placement of the steel reinforcement cage 6 into the inclined holes later, so that when it is sealed with steel fiber concrete 9, the steel reinforcement cage 6 can be more evenly and completely wrapped. After placing the steel reinforcement cage 6, a prestress needs to be applied to the steel reinforcement cage 6 to open the umbrella-shaped barbs of the steel reinforcement cage 6, and the barbs are driven into the soil to improve the uplift resistance of the pipe pile 1. Then, use a concrete pump truck 7 and a concrete delivery pump 8 to inject steel fiber concrete 9 into the inner cavity of the pipe pile 1 for bottom sealing. When sealing the bottom, first use the concrete delivery pump to inject steel fiber concrete 9 into the steel reinforcement cage 6 at the bottom of the pipe pile 1, and then insert a vibrating rod into the steel reinforcement cage 6 to vibrate the steel fiber concrete 9 to ensure that the steel fiber concrete is uniform at the position of the steel reinforcement cage 6 in the inclined hole. Then, inject steel fiber concrete 9 into the bottom of the pipe pile 1 and vibrate it evenly. The pipe pile 1 is embedded in the rock about 0.5 m. Finally, use a pile driver to drive the pipe pile 1 and send the top of the pipe pile 1 to the designated elevation position according to the design; Precast the steel reinforcement cage 6 with umbrella-shaped barbs in the steel bar processing workshop. The length of the steel reinforcement cage 6 is determined according to the length of the pipe pile 1 and the bottom bearing layer. According to the design drawings and the dimensions of the steel reinforcement cage 6, cut the steel bars for processing, and use welding or binding methods to connect the main bars and stirrups into the steel reinforcement cage 6. When welding, ensure the weld quality, and when binding, ensure the binding is firm to prevent the steel reinforcement cage 6 from deforming during transportation and installation. The umbrella-shaped barbs are welded in a circle on the keel of the steel reinforcement cage 6 by welding. The top of the placed steel reinforcement cage 6 needs to be exposed in the inner cavity of the pipe pile 1 to ensure that the center of the steel reinforcement cage 6 coincides with the center of the hole of the pipe pile 1, and the verticality deviation of the steel reinforcement cage 6 does not exceed the allowable value specified in the code; At the bottom of the pile where it is embedded in the rock stratum, by setting a circle of open steel reinforcement cages at the bottom of the pipe pile 1 and connecting them with the bottom of the pile as a whole after sealing with steel fiber concrete 9, the mechanical biting force and adhesive force between the pile body and the foundation soil at the bottom of the pile can be enhanced, and the load can be better transmitted to the deep solid rock stratum to improve the uplift resistance of the pile.

[0031] Step 2: In the aquifer 10, according to the previous geological survey, the soil layer information and groundwater occurrence information are determined, the number and position of the first coarse-grained concrete drainage holes 11 of the pipe pile 1 are designed, and the coarse-grained concrete is poured at the designated position of the pipe pile 1. The water in the aquifer 10 can enter and exit the inner cavity of the pipe pile 1 through the first coarse-grained concrete drainage holes 11, and then a cover plate 12 is installed on the top of the pipe pile 1. The cover plate 12 on the top of the pipe pile 1 and the steel fiber concrete 9 embedded in the rock layer 4 at the bottom of the pipe pile 1 seal the inner cavity of the pipe pile 1. A positive pressure is applied to the inner cavity of the pipe pile 1 through a vacuum pump 13 and a high-pressure pipe 14. A pressure gauge 15 and a plurality of control valves 16 are provided on the high-pressure pipe 14 to prevent damage caused by excessive pressure in the pipeline. The cavity applies positive pressure to squeeze the water in the inner cavity through the first coarse-grained concrete drainage hole 11 to the aquifer 10. The water in the aquifer 10 diffuses away from the pile circumference under the positive pressure of the inner cavity of the pipe pile. Then, the pile side is grouted through the pre-buried grouting pipe 17 in the pipe pile 1 until the grouting is stopped after the upper end of the pipe pile 1 emerges. After the pile side grouting is completed, the first coarse-grained concrete drainage hole 11 needs to be taken out, and the grouting liquid is chiseled at the corresponding position of the first coarse-grained concrete drainage hole 11 to the position of the aquifer, and the second coarse-grained concrete drainage hole 19 is put in. The second coarse-grained concrete drainage hole 19 connects the inner cavity of the pipe pile 1, the grouting liquid and the aquifer 10, and the water in the aquifer 10 can enter and exit the inner cavity of the pipe pile 1 through the second coarse-grained concrete drainage hole 19; The grouting pipe 17 is made of steel and does not need to be taken out after the grouting is completed. It will not affect the strength of the pipe pile 1 if it is pre-buried in the pipe pile 1. The grouting pipe 17 is connected by welding. After the pile is connected, a water flow test is required to ensure that the grouting pipe is unobstructed and not blocked. The first coarse-grained concrete is made of the same material as the second coarse-grained concrete. Negative pressure is applied to the inner cavity of the pipe pile 1 through the vacuum pump 13 and the high-pressure pipe 14, and the water of the aquifer 10 around the pipe pile 1 is sucked into the inner cavity of the pipe pile 1 through the negative pressure, and then the water is pumped into the water storage tank 21 through the drainage pipe 20 in the inner cavity of the pipe pile 1. A water outlet 22 is set behind the water storage tank 21, and the water in the water storage tank 21 can be used in other places of the construction project to save water; In the aquifer 10, the water around the pipe pile 1 is discharged to lower the groundwater level and reduce the buoyancy, thereby increasing the pull-out resistance of the pile in disguised form.

[0032] Step 3: In the hard soil layer 23, the position and thickness of the hard soil layer 23 are determined through the preliminary geological survey. When prefabricating the large-diameter pipe pile 1, two two-centimeter-thick high-pressure grouting pipes 24 are pre-buried at the designed reserved positions on both sides of the pipe pile 1. Before construction, the steel fiber concrete 9 is first injected into the concrete mixing tank 26 through the concrete delivery pump 8 of the concrete pump truck 7, and the steel fiber concrete 9 in the concrete mixing tank 26 is extracted by the high-pressure rotary jet grouting machine 27. The slurry is sprayed into the hard soil layer 23 soil body through the high-pressure nozzle 25, and is connected with the pile side grouting liquid as a whole to hook the hard soil layer 23 soil body, thereby improving the pull-out resistance of the pile; In step three, the high-pressure grouting pipe 24 is made of steel, and the high-pressure nozzle 25 is inclined upward at 45° to leak out of the pile. Multiple high-pressure nozzles 25 can be set as needed. The high-pressure rotary jet grouting machine 27 includes an air compressor and a high-pressure pump. The air compressor is pressurized to adjust the injection pressure, injection flow rate and lifting speed parameters. The pressure of high-pressure jet grouting is 20-40MPa, the air pressure is 0.7-0.8MPa, the slurry flow rate is 80-120L / min, and the lifting speed is 10-25cm / min. The high-pressure rotary jet grouting machine 27 is provided with A high-pressure gauge is used to monitor the pressure changes in real time during the grouting process to ensure that the pressure is stable. If there is an abnormal situation such as a sudden increase or decrease in pressure, a large amount of slurry bubbling, etc., the grouting should be stopped in time. The reasons may be that the pores of the formation are too large, the injection pressure is too high, or the slurry ratio is improper. Measures such as adjusting the injection parameters and adding accelerators can be taken to deal with it. In the hard soil layer 23, the steel fiber concrete 9 slurry is sprayed into the hard soil layer 23 by a high-pressure rotary jet grouting machine 27 to connect with the grouting liquid on the pile side as a whole to hook the soil of the hard soil layer 23, thereby increasing the pull-out resistance of the pile.

[0033] Step 4, soft soil layer 28, according to the position of the pipe pile 1 corresponding to the soft soil layer found in the early geological survey, a groove is set in the side wall of the prefabricated pipe pile 1, and a bag 29 is embedded in the groove. The surface of the bag 29 is uneven and serrated 30. The grouting pipe 17 pre-buried in advance is connected to the bag 29. When grouting the pile side, grouting is injected into the bag 29 through the pre-buried grouting pipe 17 until the pile end is grouted and the grouting is stopped; after the construction is completed, the grouting effect of the bag 29 needs to be tested, and the active soil pressure is tested by a micro soil pressure box to qualitatively check the grouting quality; Grouting is a key link. Following the principle of "small flow, long time", ensure that the slurry evenly fills the bag 29, so that the bag 29 is fully expanded and achieves the expected squeezing effect of the soil. The bulging bag 29 with serrations 30 on the surface of the bag 29 can better squeeze and hook out the soft soil, greatly improving the pull-out resistance of the pile. According to the thickness of the soft soil layer 28, multiple bags 29 can be set on the pile wall. After the multiple bags 29 are expanded, they form circles of bamboo piles, effectively grabbing the surrounding soil and preventing the pile from being pulled out. In the soft soil layer, by setting a serrated bag on the pile wall and grouting into the bag on the side of the pile, the expansion of the bag produces confining pressure on the pile body, forming a hoop-like effect, which can constrain the pile body and increase the lateral bearing capacity of the pile to improve the pull-out resistance of the pile.

[0034] The electrical components appearing in this article are all connected to an external main controller and 220V AC power, and the main controller can be a conventional known device that controls a computer, etc. The specific implementation method of the present disclosure omits the detailed description of known functions and known components. To ensure the compatibility of the equipment, the operating methods used are consistent with the parameters of marketed equipment.

[0035] The above description of the present invention and its implementation manners is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. In general, if those of ordinary skill in the art are inspired by it and design, without creative efforts, structural manners and embodiments similar to the technical solution without departing from the gist of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A device for improving the pull-out resistance of large-diameter non-squeezed soil pipe piles, characterized in that: It includes a pipe pile (1), a rock layer (4), a coring machine (5), a steel cage (6), a concrete pump truck (7), steel fiber concrete (9), a cover plate (12), a vacuum pump (13), a drainage pipe (20), a water storage tank (21), and a concrete mixing tank (26); An aquifer (10), a hard soil layer (23), and a soft soil layer (28) are sequentially provided at the upper end of the rock layer (4); The pipe pile (1) is sunk to a set elevation, the core drilling machine (5) drills an inclined hole into the rock layer (4) along the inner cavity of the pipe pile (1), the steel cage (6) is arranged inside the inclined hole, a concrete delivery pump (8) is provided at one end of the concrete pump truck (7), the other end of the concrete delivery pump (8) is connected to a grouting pipe (17), the grouting pipe (17) is used to inject steel fiber concrete (9) into the inner cavity of the pipe pile (1), a plurality of first coarse-grained concrete drainage holes (11) are provided on the side of the pipe pile (1), a cover plate (12) is provided at the top of the inner cavity of the pipe pile (1), a high-pressure pipe (14) is provided inside the pipe pile (1), the upper end of the high-pressure pipe (14) is connected to a vacuum pump (13), one end of the vacuum pump (13) is connected to a water tank (21), and the other end of the water tank (21) is provided with a water outlet (22); A second coarse-grained concrete drainage hole (19) is provided inside the pipe pile (1), a drainage pipe (20) is provided inside the pipe pile (1), and the upper end of the drainage pipe (20) is connected to a vacuum pump (13); Two high-pressure grouting pipes (24) are pre-buried at the designed reserved positions on both sides of the pipe pile (1), and a high-pressure nozzle (25) is provided at the lower end of each high-pressure grouting pipe (24); The concrete mixing tank (26) is used to inject steel fiber concrete (9); a pipeline at one end of the concrete mixing tank (26) is connected to a high-pressure rotary jet grouting machine (27); and a pipeline of the high-pressure rotary jet grouting machine (27) is connected to a high-pressure grouting pipe (24); The side wall of the pipe pile (1) located at the soft soil layer (28) is provided with a groove, a bag (29) is embedded in the groove, and saw teeth (30) are provided on the surface of the bag (29).

2. The device for improving the pull-out resistance of large-diameter non-squeezed soil pipe piles according to claim 1, characterized in that: A pile shoe (3) is provided at the bottom of the pipe pile (1), and pile clamps (2) are provided on both sides of the upper part of the pipe pile (1), and the pile shoe (3) is about 2 m below the rock layer.

3. The device for improving the pull-out resistance of large-diameter non-squeezed soil pipe piles according to claim 1, characterized in that: The high-pressure pipe (14) is provided with a pressure gauge (15) and a plurality of control valves (16).

4. A method for using the device for improving the pull-out resistance of large-diameter non-squeezed soil pipe piles according to claims 1-3, characterized in that: The following steps are involved: Step 1: embed the rock layer (4) at the bottom of the pipe pile (1), use a core drilling machine (5) to drill inclined holes along the inner cavity of the pipe pile (1) toward the rock layer (4), one inclined hole every 60 degrees, and a total of six inclined holes in one pipe pile (1). The inclined holes are used to place the steel cage (6) later. After drilling the inclined holes, the sediment in the holes needs to be cleaned up to facilitate the subsequent accurate placement of the steel cage (6) in the inclined holes, so that the steel cage (6) can be more evenly and completely wrapped when the bottom is sealed with steel fiber concrete (9); after placing the steel cage (6), a prestress needs to be applied to the steel cage (6), the umbrella-shaped barbs of the steel cage (6) are opened, and the barbs are inserted into the soil to improve the pipe pile (1). The pull-out resistance is then increased by injecting steel fiber concrete (9) into the inner cavity of the pipe pile (1) through a concrete pump truck (7) using a concrete delivery pump (8) to seal the bottom. When sealing the bottom, the steel fiber concrete (9) is first injected into the steel cage (6) at the bottom of the pipe pile (1) using a concrete delivery pump, and then a vibrating rod is inserted into the steel cage (6) to vibrate the steel fiber concrete (9) to ensure that the steel fiber concrete at the steel cage (6) in the inclined hole is uniform. Then, the steel fiber concrete (9) is injected into the bottom of the pipe pile (1) and vibrated evenly. The bottom of the pipe pile (1) is embedded in the rock for about 0.5m. Finally, the pile delivery device is used to deliver the pipe pile (1) to the top of the pipe pile (1) to the position of the designed elevation; Step 2: In the aquifer (10), soil layer information and groundwater storage information are determined based on the previous geological survey, and the number and position of the first coarse-grained concrete drainage holes (11) of the pipe pile (1) are designed. Coarse-grained concrete is poured at the designated position of the pipe pile (1). Water in the aquifer (10) can enter and exit the inner cavity of the pipe pile (1) through the first coarse-grained concrete drainage holes (11). Then, a cover plate (12) is installed on the top of the pipe pile (1). The cover plate (12) on the top of the pipe pile (1) and the steel fiber concrete (9) embedded in the rock layer (4) at the bottom of the pipe pile (1) seal the inner cavity of the pipe pile (1). Positive pressure is applied to the inner cavity of the pipe pile (1) through a vacuum pump (13) and a high-pressure pipe (14). A pressure gauge (15) and a plurality of control valves (16) are provided on the high-pressure pipe (14) to prevent damage caused by excessive pressure in the pipeline. Positive pressure is applied to the inner cavity of the pipe pile (1) to squeeze the water in the inner cavity out to the aquifer (10) through the first coarse-grained concrete drainage hole (11); the water in the aquifer (10) diffuses in a direction away from the pile circumference under the positive pressure in the inner cavity of the pipe pile; then, grouting is performed on the pile side through a grouting pipe (17) pre-buried in the pipe pile (1) until grouting is stopped after grouting emerges from the upper end of the pipe pile (1); after grouting on the pile side is completed, the first coarse-grained concrete drainage hole (11) is removed; grouting liquid is chiseled at a position corresponding to the first coarse-grained concrete drainage hole (11) to the position of the aquifer; and a second coarse-grained concrete drainage hole (19) is inserted; the second coarse-grained concrete drainage hole (19) is connected to the inner cavity of the pipe pile (1), the grouting liquid and the aquifer (10); water in the aquifer (10) can enter and exit the inner cavity of the pipe pile (1) through the second coarse-grained concrete drainage hole (19); Step 3: In the hard soil layer (23), the position and thickness of the hard soil layer (23) are determined through preliminary geological survey. When prefabricating the large-diameter pipe pile (1), two two-centimeter-thick high-pressure grouting pipes (24) are pre-buried at the designed reserved positions on both sides of the pipe pile (1). Before construction, the steel fiber concrete (9) is first injected into the concrete mixing tank (26) through the concrete delivery pump (8) of the concrete pump truck (7). The steel fiber concrete (9) in the concrete mixing tank (26) is extracted by a high-pressure rotary grouting machine (27), and the slurry is sprayed into the hard soil layer (23) through a high-pressure nozzle (25), and is connected with the pile side grouting liquid as a whole to hook the hard soil layer (23) soil; Step 4, soft soil layer (28), according to the position of the pipe pile (1) corresponding to the soft soil layer found in the previous geological survey, a groove is set in the side wall of the prefabricated pipe pile (1), and a bag (29) is embedded in the groove. The surface of the bag (29) is uneven and has serrated edges (30). The bag (29) is connected to a pre-buried grouting pipe (17). When grouting the pile side, grouting is injected into the bag (29) through the pre-buried grouting pipe (17) until grouting is stopped after the pile end emerges. After the construction is completed, the grouting effect of the bag (29) needs to be tested, and the active soil pressure is tested by a micro-soil pressure box to qualitatively check the grouting quality.

5. The method for using the device for improving the pull-out resistance of large-diameter non-squeezed soil pipe piles according to claim 4 is characterized in that: In step 1, a steel cage (6) with umbrella-shaped barbs is prefabricated in a steel processing workshop. The length of the steel cage (6) is determined according to the length of the pipe pile (1) and the bottom bearing layer. According to the design drawings and the size of the steel cage (6), the steel bars are cut and processed. The main bars and stirrups are connected to form the steel cage (6) by welding or binding. The quality of the weld seam must be ensured during welding. The binding must be firm to prevent the steel cage (6) from deforming during transportation and installation. The umbrella-shaped barbs are welded to the keel of the steel cage (6) by welding. The top of the placed steel cage (6) must be exposed in the inner cavity of the pipe pile (1). It is ensured that the center of the steel cage (6) coincides with the center of the hole of the pipe pile (1). The verticality deviation of the steel cage (6) does not exceed the allowable value of the specification.

6. A method for using the device for improving the pull-out resistance of large-diameter non-squeezed soil pipe piles according to claim 4, characterized in that: In step 2, the grouting pipe (17) is made of steel and does not need to be removed after grouting is completed. It is pre-buried in the pipe pile (1) and will not affect the strength of the pipe pile (1). The grouting pipe (17) is connected by welding. After the pile is connected, a water flow test is required to ensure that the grouting pipe is unobstructed and not blocked. The first coarse-grained concrete and the second coarse-grained concrete are made of the same material. Negative pressure is applied to the inner cavity of the pipe pile (1) through a vacuum pump (13) and a high-pressure pipe (14), and water in the aquifer (10) around the pipe pile (1) is sucked into the inner cavity of the pipe pile (1) through the negative pressure. Then, the water is pumped into the water storage tank (21) through the drainage pipe (20) in the inner cavity of the pipe pile (1). A water outlet (22) is provided at the rear of the water storage tank (21). The water in the water storage tank (21) can be used in other places of the construction project, thereby saving water.

7. A method for using the device for improving the pull-out resistance of large-diameter non-squeezed soil pipe piles according to claim 4, characterized in that: In step 3, the high-pressure grouting pipe (24) is made of steel, and the high-pressure nozzle (25) is inclined upward at 45 degrees to leak out of the pile. A plurality of high-pressure nozzles (25) can be provided as required. The high-pressure rotary jet grouting machine (27) includes an air compressor and a high-pressure pump. The air compressor is used to increase the pressure and adjust the injection pressure, injection flow rate and lifting speed parameters. The pressure of the high-pressure jet grouting is 20-40 MPa, the air pressure is 0.7-0.8 MPa, the slurry flow rate is 80-120 L / min, and the lifting speed is 10-25 cm / min. The high-pressure rotary jet grouting machine (27) is provided with a high-pressure gauge to monitor the pressure change in real time during the grouting process to ensure pressure stability.

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