A prestressed pipe pile post grouting device and a construction method thereof

Abstract

The application discloses a prestressed pipe pile post-grouting device (100), which comprises a grouting steel pipe (3), the pipe wall of the grouting steel pipe (3) comprises a grouting hole (30), the inside of the grouting steel pipe (3) is filled with coarse sand (7) for strengthening the rigidity of the grouting steel pipe (3), so that the grouting steel pipe (3) is guaranteed not to be damaged during pile sinking, the particle size of the coarse sand (7) is greater than the diameter of the grouting hole (3), the coarse sand (7) is prevented from leaking out of the grouting hole (30), the coarse sand (7) is dense in the grouting steel pipe (3), so that the coarse sand (7) is used for plugging the grouting hole (30) on the pipe wall of the grouting steel pipe (3) during pile sinking, and the soil is prevented from being pressed into the grouting steel pipe during the pile sinking process. According to the application, cement-soil mixing pile construction is not needed, post-grouting at the pile bottom can be performed at any time, absolute construction period is not occupied, and construction is more efficient. Compared with the prior art, the application reduces material use, is simple to process and low in installation cost.

Description

[0001] This application is a divisional application of Chinese patent application filed on June 2, 2020, with application number 202010492842.9 and invention title "A Post-Grouting Device for Prestressed Pipe Piles and its Construction Method". Technical Field

[0002] This invention relates to the field of building construction, and in particular to a post-grouting device for prestressed pipe piles and its construction method. Background Technology

[0003] Prestressed hollow square piles and prestressed pipe piles are factory-fabricated and driven using static pressure and hammer driving methods. They are characterized by high pile strength, high construction efficiency, and reliable quality. Due to the use of high-grade concrete and high compressive bearing capacity, they are widely used as compression piles in engineering construction. However, due to the relatively weak bond between the pile and soft soil layers, the bearing capacity of the foundation in many projects is far less than the pile strength, resulting in resource waste. Therefore, engineering technicians urgently need to develop methods to improve the bearing capacity of precast pile foundations. There are two main existing methods: (I) Reinforced Composite Piles: This method involves first constructing cement-soil mixing piles at the designed pile locations, and then inserting precast pile bodies into the cement-soil mixing piles to form a reinforced composite pile. The main purpose of this method is to pre-reinforce weak soil layers with cement-soil mixing piles, thereby increasing the interlocking force between the pile body and the soil, and thus improving the bearing capacity of the foundation.

[0004] This method has several drawbacks that need improvement: ① It adds an extra construction step, reducing construction efficiency; ② Cement-soil mixing pile construction requires a large amount of cement, resulting in high costs; ③ The implantation of precast piles into cement-soil mixing piles also discharges a large amount of cement and soil, causing significant environmental impact.

[0005] (II) Post-grouting at the pile bottom: This method is inspired by the post-grouting technology for bored piles to improve the bearing capacity of the pile foundation. It is more suitable for site soil layers within the pile body that are cohesive soil, silt, or gravelly soil. It mainly adopts the construction process of precast piles with grouting devices. After the static pressure pile driving is completed, post-grouting is carried out on the pile side and at the pile bottom to improve the bearing capacity of the foundation.

[0006] This method is mainly applied to prestressed concrete pipe piles. Its key technology is the post-grouting device, which can simultaneously perform post-grouting at the pile bottom and on the pile side. Its main components are steel pipes with sealing plates at both ends. One end, welded to the precast pile bottom plate, passes through a grouting pipe and is subsequently threaded to a grouting conduit inserted into the pile body for grouting. The other end can be welded to the pile tip for pile driving. Grout outlet holes are opened around the grouting device for post-grouting at the pile bottom. Protective plates are installed near the grout outlet holes to prevent the compaction of the sidewall soil during pile driving from affecting the grouting pressure at the pile bottom. Two pile side grout outlet pipes are welded to the side of the grouting device closest to the precast pile for post-grouting on the pile side. Reinforcing steel plates are welded to the outside of the grouting device to improve its strength and rigidity, ensuring its bearing capacity during pile driving. The inside of the grouting device is simultaneously filled with gravel to improve its compressive strength. Summary of the Invention

[0007] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a material-saving and environmentally friendly post-grouting device for prestressed pipe piles.

[0008] To achieve the above objectives, the present invention provides a post-grouting device for prestressed concrete pipe piles, comprising: a grout outlet steel pipe, a grout outlet steel pipe sealing plate, a rib plate, a pile sealing plate, a grouting device, a grouting pipe, and coarse sand; One end of the grout outlet steel pipe is connected to one side of the pile sealing plate, and the other end of the grout outlet steel pipe is sealed by the grout outlet steel pipe sealing plate. The wall of the grout outlet steel pipe includes a grout outlet hole. A through hole is opened on the opposite side of the pile sealing plate opposite to the grout outlet steel pipe. The grouting device is inserted into the grout outlet steel pipe through the through hole. The coarse sand is poured into the grout outlet steel pipe. The grouting pipe is connected to the grouting device. The rib is perpendicularly connected to the surface of the pile sealing plate and the periphery of the grout outlet steel pipe. There is at least one rib.

[0009] Furthermore, the ribs are cross-shaped.

[0010] Furthermore, there are multiple slurry outlet holes.

[0011] Furthermore, the grouting device includes a check valve.

[0012] Furthermore, the end of the grouting pipe connected to the grouting device includes a connecting thread.

[0013] Furthermore, the corners of the rib are chamfered.

[0014] This invention also discloses a construction method using the aforementioned prestressed pipe pile post-grouting device, comprising: The prestressed pipe pile post-grouting device is welded to the pile body; Connect the grouting pipe to the grouting device; The grouting expansion prestressed pipe pile and the grouting pipe are driven into the soil using the direct pile driving process until the pile reaches the design elevation. Cement grout is injected, and the cement grout is injected into the bottom of the pile through the grouting pipe and the grouting device after the prestressed pipe pile, forming an expansion section at the bottom of the pile.

[0015] Furthermore, the cement slurry uses P42.5 cement with a water-cement ratio between 0.55 and 0.60.

[0016] Furthermore, the direct pile driving process is either a static pressure process or a hammer driving process.

[0017] The technical advantages of this invention are: no cement-soil mixing pile construction is required, post-grouting at the pile bottom can be carried out at any time without affecting the absolute construction period, resulting in more efficient construction. In particular, compared with existing post-grouting devices, it reduces material usage, simplifies processing, and lowers installation costs.

[0018] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0019] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a cross-sectional view of a post-grouting device according to an embodiment of the present invention; Figure 2 This is a top view of a post-grouting device according to an embodiment of the present invention; Figure 3 This is a cross-sectional view of the construction state according to an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached drawings: 100-Post-grouting device; 200-Pile body; 1-Pile sealing plate; 2-Rib plate; 3-Grouting steel pipe; 4-Grouting steel pipe sealing plate; 5-Grouting device; 6-Grouting pipe; 7-Coarse sand; 10-Opening; 20-Welding surface. Detailed Implementation

[0021] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0022] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0023] like Figure 1 and Figure 2 As shown, the present invention discloses a post-grouting device for prestressed pipe piles, comprising: a grout outlet steel pipe 3, a grout outlet steel pipe sealing plate 4, a rib plate 2, a pile sealing plate 1, a grouting device 5, a grouting pipe 6, and coarse sand 7.

[0024] The grout outlet steel pipe 3 is a hollow steel pipe. One end of the grout outlet steel pipe 3 is connected to one side of the pile sealing plate 1, and the other end of the grout outlet steel pipe 3 is sealed by the grout outlet steel pipe sealing plate 4. The pipe wall of the grout outlet steel pipe 3 includes multiple grout outlet holes 30. A through hole 10 is opened on the opposite side of the pile sealing plate 1 opposite to the grout outlet steel pipe 3. The grout injector 5 is inserted into the grout outlet steel pipe 3 through the through hole 10. Coarse sand 7 is filled into the grout outlet steel pipe 3. The grouting pipe 6 is connected to the grout injector 7. The rib plate 2 is perpendicularly connected to the pile sealing plate 1, and there is at least one rib plate 2. Preferably, the particle size of the coarse sand 7 should be larger than the diameter of the grout outlet hole 30 to prevent coarse sand from leaking out of the grout outlet hole 30.

[0025] Multiple grout outlet holes 30 are distributed around the wall of the grout outlet steel pipe 30. During grouting by the grouting device 5, cement grout overflows from the outlet holes 30 into the soil, permeating and compacting the soil around the pile. Consequently, the soil around the pile undergoes upward pressure and expansion under the action of high-pressure cement grout, gradually reinforcing the pile perimeter and changing the consolidation state of the surrounding soil. This increases the pull-out resistance and bearing capacity of the pipe pile. In a preferred embodiment, there are multiple grout outlet holes 30, each with a diameter of 8–10 mm.

[0026] Since the grout outlet pipe 3 is a hollow steel pipe, and because it is in direct contact with the soil and bears the most stress, it needs to be reinforced during pile driving. In this embodiment, coarse sand 7 is used to fill the grout outlet pipe 3 to enhance its rigidity and ensure it is not damaged during pile driving. Simultaneously, during grouting, the cement grout can flow through the gaps between the coarse sand 7 particles without affecting the grouting pressure. Furthermore, the coarse sand 7 is also used to plug the grout outlet hole 30 during pile driving, preventing soil from being forced into the grout outlet pipe 3 as the pile drives forward. Therefore, the coarse sand 7 within the grout outlet pipe 3 should be dense.

[0027] Furthermore, the ribs 2 are multiple and cross-shaped to further break through the soil and increase the pressure of the pipe pile during the pile driving process.

[0028] Furthermore, the diameter of the slurry outlet pipe sealing plate 4 is larger than the diameter of the slurry outlet pipe 3. This facilitates the connection between the slurry outlet pipe sealing plate 4 and the slurry outlet pipe 3, preferably by welding.

[0029] Furthermore, the grouting device 5 includes a check valve to prevent backflow of cement grout injected through the grouting pipe 7.

[0030] Furthermore, in order to fix the grouting pipe 7 and the grouting device 5 and prevent the grouting pipe 7 from deviating from the grouting device 5 during the pile driving process, threads can be machined on the end of the grouting pipe 7, and the grouting pipe 7 and the grouting device 5 are threadedly connected.

[0031] Furthermore, the corners of the rib plate 2 are chamfered to reduce the resistance of the soil to the pile body during pile driving.

[0032] Furthermore, the pile body 200 and the post-grouting device 100 are separate components, allowing the pile body 200 and the post-grouting device 100 to be manufactured separately in the factory and transported to the construction site, where they can be directly welded together. Figure 3 The pile body 200 and the weld surface 20 with the post-grouting device 100 are shown.

[0033] This invention also discloses a construction method using the aforementioned prestressed pipe pile post-grouting device, comprising: Step S201: Weld the post-grouting device 100 to the pile body 200; Step S202: Connect the grouting pipe 6 to the grouting device 5; Step S203: The grouting expansion prestressed pipe pile and the grouting pipe are driven into the soil using the direct pile driving process until the pile reaches the design elevation; Step S204: Inject cement grout, which flows along the grouting pipe to the bottom of the prestressed pipe pile grouting device, forming an expansion section at the bottom of the pile.

[0034] Cement grout can be injected into the grouting pipe 6 using a high-pressure grouting pump. This construction method reduces the concrete pouring or mud replacement steps required in conventional pile driving, simplifying the process. Furthermore, the cement grout is directly injected through the grouting pipe 6 and overflows from the grout outlet 30, reducing the amount of cement grout used and controlling its flow path, thus minimizing material consumption, lowering costs, and having minimal environmental impact. Simultaneously, the pull-out resistance and stability of the prestressed concrete pipe piles remain unaffected, maintaining significant foundation bearing capacity. The direct pile driving techniques employed include static pressure or hammer driving, requiring simple equipment and offering wide applicability.

[0035] Furthermore, the cement slurry uses P42.5 cement with a water-cement ratio between 0.55 and 0.60. P42.5 refers to the strength grade of ordinary Portland cement, meaning that the 28-day compressive strength standard for ordinary Portland cement is not less than 42.5 MPa.

[0036] When preparing cement grout, careful stirring is essential to prevent segregation. The mixing system should have two grout tanks (a mixing tank and a holding tank). The cement mortar must be stirred in the mixing tank, filtered through a screen, and then placed in the dedicated holding tank. The holding tank should also be equipped with a mixing system, and the grout should not remain in the holding tank for more than 3 hours. During grouting, the grouting pressure and rate must be strictly controlled. The termination of grouting should be based on a dual control standard of grouting volume and pressure. The grouting flow rate should not exceed 50 L / min and should not be lower than the design requirements. The grouting pressure should be controlled between 1.0 and 1.8 MPa.

[0037] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A prestressed pipe pile post grouting device, characterized in that, The prestressed pipe pile post-grouting device includes a grout outlet steel pipe, the pipe wall of which includes grout outlet holes. The interior of the grout outlet steel pipe is filled with coarse sand to enhance its rigidity. The particle size of the coarse sand is larger than the diameter of the grout outlet holes. The coarse sand is dense in the grout outlet steel pipe, thereby blocking the grout outlet holes on the pipe wall during pile driving. The grout outlet steel pipe is a hollow steel pipe. One end of the grout outlet steel pipe is connected to one side of the pile sealing plate, and the other end of the grout outlet steel pipe is sealed by the grout outlet steel pipe sealing plate. A through hole is opened on the opposite side of the pile sealing plate and the grout outlet steel pipe. The grouting device is inserted into the grout outlet steel pipe through the through hole and the grouting pipe is connected to the grouting device. The grouting device is then welded to the pile body. The cement grout flows along the grouting pipe to the bottom of the grouting device of the prestressed pipe pile, forming an expansion section at the bottom of the pile.

2. The post-grouting device for a prestressed pipe pile according to claim 1, characterized in that, The prestressed pipe pile post-grouting device also includes a rib plate, which is perpendicularly connected to the surface of the pile sealing plate and the periphery of the grout outlet steel pipe in a cross shape.

3. The post-grouting device for prestressed pipe piles as described in claim 2, characterized in that, The ribs are cross-shaped.

4. The post-grouting device for prestressed pipe piles as described in claim 2, characterized in that, There is at least one rib.

5. The post-grouting device for prestressed concrete pipe piles as described in any one of claims 1 to 4, characterized in that, The slurry outlet steel pipe has multiple slurry outlet holes on its pipe wall.

6. The post-grouting device for prestressed concrete pipe piles as described in any one of claims 1 to 4, characterized in that, The grouting device includes a check valve.

7. The post-grouting device for prestressed concrete pipe piles as described in claim 6, characterized in that, The end of the grouting pipe that connects to the grouting device includes a connecting thread.

8. The post-grouting device for prestressed pipe piles as described in claim 2, characterized in that, The corners of the ribs are chamfered.

9. The post-grouting device for prestressed pipe piles as described in claim 5, characterized in that, The diameter of each slurry outlet hole on the pipe wall of the slurry outlet steel pipe is 8-10 mm.

10. A construction method using the post-grouting device for prestressed concrete pipe piles according to any one of claims 1 to 9, characterized in that, The method includes: The prestressed pipe pile post-grouting device is welded to the pile body; Connect the grouting pipe to the grouting device; The prestressed pipe piles and the grouting pipes are driven into the soil using the direct pile driving process until the piles reach the design elevation. Cement grout is injected and flows along the grouting pipe to the bottom of the prestressed pipe pile grouting device, forming an expansion section at the bottom of the pile.

11. The construction method as described in claim 10, characterized in that, The cement slurry uses P42.5 cement with a water-cement ratio between 0.55 and 0.

60.

12. The construction method as described in claim 10 or 11, characterized in that, The direct pile driving process is either a static pressure process or a hammer driving process.

13. The construction method as described in claim 10, characterized in that, The cement grout is injected into the grouting pipe using a high-pressure grouting pump.

Images