A combined post-grouting device for ring-ribbed prestressed pipe piles and its construction method
Through the combined post-grouting device of the ring-ribbed prestressed pipe pile, the synergistic effect of multiple grouting reinforcement mechanisms on the pile side and pile end is achieved, solving the problems of low pile side resistance and large soil squeezing effect of traditional prefabricated pipe piles in deep soft soil foundations, and improving the bearing capacity of the pile foundation and the project quality.
Patent Information
- Application Number
- CN202310039948.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-01-12
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2043-01-12
AI Technical Summary
Traditional prefabricated pipe piles have low pile side resistance in deep soft soil foundations and are greatly affected by the soil squeezing effect. The single grouting method is not effective and it is difficult to improve the bearing capacity and project quality.
A combined post-grouting device for ring-ribbed prestressed pipe piles is used, combined with closed and open grouting on the pile side. Through the ring-ribbed prestressed pipe piles, steel pile caps, cast iron pile tips, grouting outer and inner pipes, simultaneous grouting of the pile sides and pile ends is achieved. The hollow closed grouting chambers and open grouting pipes are arranged in an alternating manner to form a combination of grouting reinforcement mechanisms.
It improves the bearing capacity of pile foundation, reduces the soil squeezing effect of pile sinking, expands the scope of grouting reinforcement, enhances the grouting effect, optimizes the construction quality, and expands the scope of use of prestressed pipe piles.
Smart Images
Figure CN116240882B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of building foundation construction, in particular to a combined post-grouting device for ring-ribbed prestressed pipe piles and a construction method thereof. Background Art
[0002] With the rapid development of construction technology, the field of pile foundation construction is changing with each passing day. Common prestressed pipe piles are a widely used type of pile foundation. Compared with traditional sunken pipe cast-in-place and bored cast-in-place piles, prefabricated pipe piles offer advantages such as factory production, high-quality piles, simple construction technology, short construction period, low cost, and convenient supervision. Therefore, they are widely used in foundation projects such as high-rise buildings, bridges, power facilities, and docks. However, when prestressed pipe piles are used as foundations in deep soft soil, their side resistance is low and they are significantly affected by the excess pore water pressure caused by the soil squeezing effect. This is extremely unreasonable for prestressed pipe piles that are primarily designed as friction piles. Due to economic factors, it is not advisable to increase the bearing capacity by increasing the pile length, pile diameter, or increasing the number of piles.
[0003] Post-grouting is a common pile reinforcement technique that combines pile foundation and grouting technologies. Generally, grout is pumped into the pile through a grouting pipe using a high-pressure pump to solidify the soil at the pile end and sides, thereby increasing the bearing capacity of the pile foundation and reducing pile foundation settlement. Currently, the most commonly used post-grouting methods are open grouting and closed grouting. Both grouting methods have their advantages and disadvantages. Open grouting involves directly pressing the grouting liquid into the soil layer through a grouting pipe. This method has low controllability of the grouting area and a discrete distribution of the grouting liquid. Furthermore, the grouting pressure and volume cannot be effectively controlled, resulting in poor grouting results. Closed grouting involves pressing the grouting liquid through a grouting pipe into a pre-designed expandable capsule, confining the grouting liquid to expand the capsule and form an enlarged head. However, closed grouting cannot solidify the soil around the pile. Clearly, single open or closed grouting methods still have significant shortcomings in post-grouting construction, and there is still significant room for improvement in the bearing capacity of pile foundations.
[0004] In summary, in the current prefabricated pipe pile construction, the single grouting method can no longer effectively achieve the purpose of reducing the length and diameter of prefabricated pipe piles and reducing the settlement and deformation of pile foundations, thereby improving economic benefits and project quality when faced with complex geological conditions. Summary of the Invention
[0005] The purpose of the present invention is to solve the problems of small range of traditional closed grouting reinforcement, difficult control of traditional open grouting reinforcement area, poor grouting effect of local soft soil layers, adverse effects caused by pile sinking soil squeezing effect, and difficulty in pile sinking due to the existence of hard interlayers or dense sand layers underground. A combined post-grouting device for ring-ribbed prestressed pipe piles is provided to improve the stability of the grouting construction quality of prestressed pipe piles, better control the grouting area, grouting pressure and grouting amount, realize joint grouting of the pile side and pile end, and further improve the bearing capacity of the prestressed pipe piles.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] A combined post-grouting device for a ring-ribbed prestressed pipe pile comprises a ring-ribbed prestressed pipe pile body, a steel pile cap, a pile-side closed grouting device, a cast iron conical pile tip, a grouting outer tube and a grouting inner tube that cooperate with each other. The steel pile cap is sleeved on the upper end of the ring-ribbed prestressed pipe pile body, the cast iron conical pile tip is connected to the lower end of the ring-ribbed prestressed pipe pile body, and the pile body is prefabricated with a pile-side closed grouting device and a grouting outer tube that runs through the entire pile body.
[0008] A fixed sleeve is provided in the steel pile cap, which is sleeved and connected to the upper end of the grouting outer tube, and lateral supports are connected around the fixed sleeve to limit the position of the sleeve and stabilize the grouting outer tube so that it will not rotate horizontally during the pile sinking process;
[0009] Each pile-side closed grouting device is equipped with three hollow closed grouting chambers wrapped in rubber capsules. The hollow closed grouting chambers are evenly distributed at equal angles in a dart shape in the pile-side closed grouting device. The hollow closed grouting chambers of the upper and lower adjacent pile-side closed grouting devices are distributed at staggered angles.
[0010] The grouting outer pipe also includes a pile side transverse grouting pipe and a spherical pressure chamber. The grouting outer pipe is connected to the pile side transverse grouting pipe through the spherical pressure chamber. The pile side transverse grouting pipe includes an open grouting pipe and a closed grouting pipe. The open grouting pipe and the closed grouting pipe on the same pile side grouting section are evenly distributed in a spoke-like manner along the radial direction of the ring-rib prestressed pipe pile body, and the open grouting pipes on different pile side grouting sections are distributed at a cross-angle.
[0011] An open grouting outlet is provided at the side of the pile body where the open grouting pipe is connected to the pile body. A disc-shaped permeable stone with a filling cotton wrapped around its side is embedded in the open grouting outlet. The diameter of the permeable stone and the open grouting outlet are adapted to each other, so as to provide good protection for the open grouting outlet during the transportation and sinking of the prefabricated pipe pile.
[0012] The grouting inner pipe is arranged in the grouting outer pipe, which includes a top pipe, a middle pipe and a bottom pipe connected in sequence. The connection between the top pipe and the middle pipe, and the connection between the middle pipe and the bottom pipe are provided with an inner pipe slurry outlet. An inflatable air bag is respectively provided above and below the inner pipe slurry outlet. The air supply pipe connected to the inflatable air bag is arranged close to the outer wall of the grouting inner pipe. The inflated inflatable air bag is arranged close to the inner wall of the grouting outer pipe, so that a closed pressure chamber is formed inside the grouting outer pipe, and the slurry outlet range of the inner pipe slurry outlet covers the space size of the spherical pressure chamber.
[0013] Furthermore, the cast iron conical pile tip includes a cone body, which is connected to the ring-rib prestressed pipe pile body through a pile tip connector. A pile end grouting ring pipe and a group of pile end transverse grouting pipes are provided in the cone. The pile end transverse grouting pipe is connected to the spherical pressure chamber of the grouting outer pipe. A horizontal grouting ring pipe outlet is provided at the connection between the pile end transverse grouting pipe and the pile end grouting ring pipe. A group of inclined pile end grouting side pipes are connected to the bottom of the pile end grouting ring pipe. Each pile end grouting side pipe is provided with a group of grouting side pipe outlets. The diameter of the grouting ring pipe outlet is smaller than that of the grouting side pipe outlet to ensure the same slurry discharge volume during the grouting process. The axis of the pile end grouting side pipe is inclined at an angle of 60° to the horizontal plane of the pile end grouting ring pipe, and the spacing between two adjacent pile end grouting side pipes is the same. Corresponding soil guide separation ribs are provided below the pile end grouting side pipes, which are fixed on the cast iron conical pile tip. The circumferential range of the soil guide separation ribs is greater than the diameter length of the pile end grouting side pipe to provide better protection for the side pipes.
[0014] Furthermore, a group of convex annular ribs are provided on the pile body of the annular rib prestressed pipe pile, and the convex annular ribs are horizontally arranged every 1 to 3 meters along the outer wall of the pile body, and the top pipe and the middle pipe, and the middle pipe and the bottom pipe of the grouting inner pipe are respectively connected and assembled by bolts, and the positions of the bolts are staggered with the positions of the lateral grouting pipes on the pile side to ensure that the grouting will not be hindered during grouting.
[0015] Furthermore, the inner diameter and outer diameter of the pile side closed grouting device are respectively the same as the inner and outer diameters of the ring-ribbed prestressed pipe pile body, so as to prevent the pile side closed grouting device from being crushed due to protrusion during the pile sinking process.
[0016] In order to further achieve the purpose of the present invention, a construction method of a combined post-grouting device for ring-rib prestressed pipe piles is provided, and the specific steps are as follows, including:
[0017] (1) The pile body of the ring-rib prestressed pipe pile is made by prestressing technology and centrifugal forming method. The pile body is prefabricated with a closed grouting device on the pile side and a grouting outer pipe arranged throughout the pile body. The grouting inner pipe is arranged inside the grouting outer pipe;
[0018] (2) The steel pile cap is fitted onto the upper end of the ring-ribbed prestressed pipe pile body to protect the pile head from being damaged when the pile is driven by hammer. The cast iron conical pile tip is welded to the ring-ribbed prestressed pipe pile body through a pile tip connector;
[0019] (3) The inner grouting tubes are tightly connected by stacking threaded connectors. The diameter of the inner grouting tubes is smaller than that of the outer grouting tubes. The inner grouting tubes can be flexibly moved up and down in the outer grouting tubes according to the different grouting positions on the pile side. During grouting construction, the grouting outlet of the inner tube is moved to the desired grouting position, and the inflatable airbag is inflated through the air pipe arranged on the outer wall of the inner grouting tube to form a closed pressure chamber in the outer grouting tube, thereby grouting the designated position;
[0020] (4) After the prestressed pipe piles are delivered to the soil layer at the designed depth, the cement slurry is pumped into the grouting inner pipe by a high-pressure pump on the ground, and then transferred to the closed pressure chamber consisting of the grouting inner pipe, the inflatable air bag and the grouting outer pipe. The grouting slurry is then sent to the grouting outlet through the prefabricated grouting pipes on the pile side and pile end and ejected.
[0021] Furthermore, in step (3), if open grouting is performed on the pile side and pile end simultaneously, a middle pipe of the grouting inner pipe of appropriate length is selected and stacked and connected with the top pipe by bolts to achieve the length of the grouting pipe; if open grouting is performed only on the pile end, it is only necessary to select a top pipe of appropriate length and send it to the spherical pressure chamber at the end of the pile body; if grouting is performed only on the designated position on the pile side, the top pipe, the middle pipe and the bottom pipe are stacked and connected by bolts to achieve the length of the grouting pipe.
[0022] Furthermore, during the pipe pile construction process, if the pipe pile encounters a hard soil layer when being hammered into the soil, the pile sinking process is temporarily stopped first, and a grouting inner tube is selected for grouting only at the pile end. A high-pressure water source is pressed into the grouting inner tube from the grouting inlet at the top of the pile body, so that the high-pressure water source is ejected from the horizontal grouting ring tube outlet and the lateral grouting side tube outlet to soften the soil layer at the pile end, so that the pipe pile can pass smoothly when encountering a hard interlayer. After the water injection pressure value drops sharply and the water pressure value is maintained for several minutes, the prefabricated pipe pile is sunk again.
[0023] Furthermore, during the closed grouting process, the hollow closed grouting chamber of the pile side closed grouting device is controlled by the grouting pressure and grouting amount to prevent it from excessive expansion and rupture or insufficient compaction of the pile side soil. After the grouting amount or grouting pressure meets the design requirements, the grouting is stopped. After the cement in the hollow closed grouting chamber is solidified, a permanent dart-shaped cement body can be formed on the pile side of the prestressed pipe pile, thereby enhancing the bearing capacity of the prestressed pipe pile.
[0024] Furthermore, the transversely opened grouting outlet on the pile side is also used as a drainage outlet for the prefabricated pipe pile. During the static pressure pile sinking process in deep soft soil foundation, due to the soil squeezing effect of pile sinking, the soft clay around the pile will produce a higher pore water pressure under the action of squeezing and disturbance. The pore water in the soil layer around the pile is filtered into the grouting outer pipe through the permeable stone, and then the pore water in the grouting outer pipe is pumped out by the ground water pump, reducing the stress increment and excess pore water pressure generated in the pile sinking process, thereby effectively reducing the damage of the soil squeezing effect to the project.
[0025] Furthermore, in the step (4), during the post-grouting process, the pile body of the ring-ribbed prestressed pipe pile is first subjected to open grouting on the pile side and pile end, and the grouting is stopped when slurry emerges from the ground at the pile top; the grouting inner pipe combination connection mode is reassembled, and the pile end and the local weak soil layer on the pile side are grouted separately; then the hollow closed grouting chamber in the closed grouting device on the pile side is grouted to form a dart-shaped expansion joint ring; finally, the pile side open grouting is performed to fill the hollow part caused by the grouting and compacting of the soil layer by the closed grouting device.
[0026] Compared with the prior art, the specific advantages of the technical solution of the present invention are:
[0027] (1) The present invention integrates a pile-side closed grouting device into a prestressed pipe pile by prefabrication. A "dart-shaped" hollow closed grouting chamber is provided in the closed grouting device, which can reduce the local weakening of the pile body by the closed grouting device formed by the traditional annular capsule. On the basis of improving the bearing capacity of the prefabricated pipe pile, the pile foundation size is further optimized and reduced, thereby reducing the project cost.
[0028] (2) The present invention utilizes a disassembly and installation combination of a grouting inner tube, combined with a grouting outer tube inside a pile, to achieve simultaneous grouting of the pile end and pile side, as well as separate grouting of the soft soil layer locally entrained in the pile body, thereby avoiding the problems of uneven and single grouting effect of traditional post-grouting devices, unstable grouting construction quality, and substandard bearing capacity of post-grouting prestressed pipe piles;
[0029] (3) The present invention expands the scope of grouting reinforcement, facilitates the control of the grouting slurry reinforcement area, improves the grouting effect, and concentrates the three grouting reinforcement mechanisms of compaction, penetration and splitting on the pile side and pile end through the combined post-grouting device, greatly enhancing the pile side resistance and pile end bearing capacity of the prestressed pipe pile, thereby effectively ensuring the grouting construction quality and enhancing the bearing capacity of the post-grouting prestressed pipe pile, further expanding the scope of use of the prestressed pipe pile;
[0030] (5) The present invention can achieve the purpose of softening the soil layer by jetting water during the pile sinking process, thereby assisting the pile sinking process. This avoids the defects of traditional prefabricated pipe piles, such as poor pile sinking effect when a local hard interlayer appears in the local soil layer, and even cracking of the pile head and pile body under heavy pressure.
[0031] (6) The present invention achieves the goal of filtering the pore water around the pile into the outer grouting pipe through the horizontally opened slurry outlet on the side of the pile and discharging it to the ground during the pile sinking process in deep soft soil. This accelerates the dissipation of the excess pore water pressure generated by the soft clay around the pile under the action of squeezing and disturbance, greatly reducing the stress increment and excess pore water pressure generated during the pile sinking process, thereby effectively reducing the damage of the soil squeezing effect to the project. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 This is a schematic diagram of the overall layout of the combined post-grouting device for ring-rib prestressed pipe piles of the present invention;
[0033] Figure 2 This is a schematic diagram of the steel pile cap structure of the present invention;
[0034] Figure 3 Schematic diagram of the open grouting outlet structure of the pile side transverse grouting pipe of the present invention;
[0035] Figure 4 It is a schematic diagram of the three-dimensional structure of the pile side closed grouting device of the present invention;
[0036] Figure 5 It is a schematic diagram of the cooperation between the pile side closed grouting device and the grouting outer pipe of the present invention;
[0037] Figure 6 This is a schematic diagram of the grouting inner pipe structure of the present invention;
[0038] Figure 7 This is a schematic diagram of the effect of using the inner and outer pipes in combination when grouting the pile sides and pile ends simultaneously according to the present invention;
[0039] Figure 8 This is a schematic diagram of the effect of using the inner and outer pipes in combination when only the pile side is grouting according to the present invention;
[0040] Figure 9 This is a schematic diagram of the effect of using the inner and outer pipes in combination when only the pile end is grouting according to the present invention;
[0041] Figure 10 Schematic diagram of the three-dimensional structure of the cast iron conical pile tip of the present invention;
[0042] Figure 11 A top view of the cast iron conical pile tip of the present invention;
[0043] Figure 12 This is a schematic diagram of the internal piping structure of the cast iron conical pile tip of the present invention;
[0044] Figure 13 This is a rendering of the ring-ribbed prestressed pipe pile of the present invention before grouting;
[0045] Figure 14It is a schematic diagram of the slurry diffusion effect of the pipe pile of the present invention during the combined post-grouting. Implementation Method Example
[0046] To make the present invention more clear, the following further describes a combined post-grouting device for ring-rib prestressed pipe piles and its construction method in conjunction with the accompanying drawings. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0047] The device of the present invention comprises a ring-ribbed prestressed pipe pile body 1, a steel pile cap 2, a pile side closed grouting device 3, a cast iron conical pile tip 4, a grouting outer pipe 5, and a grouting inner pipe 6.
[0048] See also Figures 1 to 5 The pile body 1 of the illustrated ring-rib prestressed pipe pile is 12 m long. The pile-side closed grouting device 3, the grouting outer pipe 5, the open grouting pipe 5011 and the closed grouting pipe 5012 of the pile-side transverse grouting pipe 501, and the open grouting outlet 503 are prefabricated inside the pile body. The grouting outer pipe 5 is connected to the pile-side transverse grouting pipe 501 through the spherical pressure chamber 502 and is connected by welding.
[0049] The number of pile-side closed grouting devices 3 to be arranged is determined according to the pile length. For a pile with a length of 12m, it should be arranged for the first time 4m above the pile end, and then another one should be arranged at a position 4m apart along the pile length. Preferably, the pile-side closed grouting device 3 is provided with hollow closed grouting chambers 301 wrapped with rubber capsules in different numbers according to the size of the pile diameter. The inner and outer diameters of the pile-side closed grouting device 3 should be adapted to the inner and outer diameters of the annular rib-shaped prestressed pipe pile body 1 to prevent the pile-side closed grouting device 3 from being crushed due to protrusion during the pile sinking process.
[0050] See also Figure 2 The inner and outer diameters of the steel pile cap 2 are adapted to the inner and outer diameters of the ring-ribbed prestressed pipe pile body 1. The thickness of the pile cap should be: when the pile body is sleeved and connected, the grouting outer tube 5 is slightly lower than the top surface of the steel pile cap 2 to ensure that it is not affected by the impact of a heavy hammer; the diameter of the fixed sleeve 201 is slightly larger than the diameter of the grouting outer tube 5, and is fixed in position by lateral support. During the pile sinking process, the fixed grouting outer tube 5 is not rotated in the horizontal direction.
[0051] See also Figure 3 、 Figure 4 and Figure 5The open grouting pipe 5011 is connected to the side of the pile body and is provided with an open grouting outlet 503. The side of the round permeable stone 504 is wrapped with filling cotton and embedded in the horizontal open grouting outlet 503 on the pile side. The diameter of the permeable stone 504 is adapted to the open grouting outlet 503 and is slightly larger than the diameter of the open grouting pipe 5011. It is not easy to fall off during the transportation and sinking of the prefabricated pipe piles, and it plays a good protective role for the horizontal open grouting outlet on the pile side. During the grouting construction process, the permeable stone 504 can be flushed out under the pressure of the high-pressure cement slurry pumped in by the high-pressure pump, and the impact on the post-grouting construction can be ignored.
[0052] See also Figure 4 and Figure 5 The pile-side closed grouting device 3 is provided with a hollow closed grouting chamber 301 wrapped with a rubber capsule, which is evenly arranged at equal angles in a "dart shape". The rubber capsule is seamlessly bonded to the concrete part of the pile body, meeting the requirements of air tightness and adhesion. The hollow closed grouting chambers of the first pile-side closed grouting device and the second pile-side closed grouting device arranged above and below are distributed at cross angles in the vertical direction.
[0053] See also Figure 6 The grouting inner pipe 6 is composed of a top pipe 601, a middle pipe 602, and a bottom pipe 603 connected by four bolts 607. Different grouting inner pipe connection combinations are made for different grouting methods and grouting positions; the diameter of the grouting inner pipe 6 is slightly smaller than the diameter of the grouting outer pipe 5, which is convenient for lifting up and down; the position of the bolt 607 is staggered with the horizontal grouting pipe 501 on the pile side to ensure that the grouting will not be hindered during grouting; the inflatable airbag 605 is annular, which is bonded to the upper and lower parts of the inner pipe slurry outlet 604, and it meets the requirements of air tightness and adhesion. The inflatable airbag 605 is inflated through the air supply pipe 606. The inflated airbag is tightly attached to the inner wall of the grouting outer pipe 5, thereby forming a closed pressure chamber inside the grouting outer pipe 5, and the slurry outlet range of the inner pipe slurry outlet 604 in the grouting inner pipe 6 covers the space size of the spherical pressure chamber 502;
[0054] See also Figure 10 、 Figure 11 and Figure 12The cast iron conical pile tip 4 includes a cone body 401, which is welded to the pile body through a pile tip connector 402, and the diameter of the conical bottom surface is adapted to the inner and outer diameters of the ring-ribbed prestressed pipe pile body 1; the pile end grouting ring pipe 403 and four pile end transverse grouting pipes 404 are prefabricated in the conical cone, and are connected to the grouting outer pipe 5 through the four pile end transverse grouting pipes 404; a horizontal grouting ring pipe outlet 405 is provided at the connection between the pile end transverse grouting pipe 404 and the pile end grouting ring pipe 403, and the pile end grouting side pipe 406 is inclined at an angle of 60° to the horizontal plane of the pile end grouting ring pipe 403. The four pile end grouting side pipes 406 are evenly spaced with two lateral grouting side pipe outlets 407. The diameter of the grouting ring pipe outlet 405 is smaller than that of the grouting side pipe outlet 407, ensuring that the grouting volume is the same during the grouting process. In order to protect the pile end grouting side pipes 406 and the grouting side pipe outlets 407 from being squeezed and damaged by the pile end soil layer during the pile sinking process, a soil guide separation rib 408 is arranged below the pile end grouting side pipe 406 and welded to the tapered pile tip. The circumferential range of the soil guide separation rib 408 is greater than the diameter of the pile end grouting side pipe 406, which can play a better protective role.
[0055] During the construction process of the device of the present invention: when the pile body 1 of the ring-ribbed prestressed pipe pile is facing a hard soil layer construction environment such as dense sandy soil, there is a problem of difficulty in sinking the pile, the pile sinking process can be temporarily stopped, and the top pipe 601 of the grouting inner pipe 6 of appropriate length is sent to the spherical pressure chamber 502 at the end of the pile body, and a high-pressure water source is pressed into the grouting inlet of the grouting inner pipe 6 at the top of the pile body, so that the high-pressure water source is slurry-discharged from the grouting ring pipe outlet 405 horizontally to the pile end grouting ring pipe 403 and the pile end grouting side pipe 406 laterally. The grouting side pipe 407 is ejected to soften the soil layer at the pile end, so that the pipe pile can pass smoothly when encountering a hard interlayer. After the water injection pressure value drops sharply and the water pressure value is maintained for several minutes, the prefabricated pipe pile is sunk again; the above operation is repeated until the pile sinking is completed; the hard soil layer is split and softened under the action of high-pressure water, making it easier for the slurry to combine with the softened hard soil layer during the subsequent grouting device construction, and better play the role of the post-grouting construction in improving the bearing capacity of the pile foundation.
[0056] Preferably, in actual engineering applications, prestressed pipe piles with a diameter of 500mm to 800mm are more commonly used. In order to further improve the bearing capacity characteristics of prestressed pipe piles, combined with the pile end water jetting assisted sinking construction process set in this device, it is recommended to increase the diameter of the prestressed pipe piles to 1500mm; on this basis, further adjustments are made to the pile side closed grouting device: when the pile diameter is less than 600mm, three hollow closed grouting chambers 301 wrapped with rubber capsules are set; when the pile diameter is 600mm to 1000mm, four hollow closed grouting chambers 301 wrapped with rubber capsules are set; when the pile diameter is 1000mm to 1500mm, six hollow closed grouting chambers wrapped with rubber capsules are set. Example
[0057] During the construction process using the device of the present invention: when the ring-ribbed prestressed pipe pile body 1 faces the deep soft soil foundation construction environment, the soil around the pile is disturbed by the pile sinking construction process, and a large amount of pore water is generated that cannot dissipate in time, forming a high pore water pressure. The pile sinking soil squeezing effect has a very adverse impact on the pile body and the surrounding environment.
[0058] By arranging the horizontal grouting pipe 501 on the pile side of the device, the open grouting port 5011 is used as a drainage hole, and the pore water in the soil layer around the pile is filtered through the permeable stone 504 and retained in the grouting outer pipe 5 in the pile body. A water pump is used on the ground to pump out the pore water in the grouting outer pipe 5, thereby effectively reducing the impact of the soil squeezing effect, reducing the water content of the soil, improving the strength of the soil, and enhancing the bearing capacity of the foundation. After the soil around the pile is consolidated to a stable state, the grouting device is used to grout and reinforce the soil at the pile end and pile side to further improve the bearing capacity of the pile foundation. Example
[0059] During the construction process of the device of the present invention: Figure 7 If open grouting is performed on the pile side and pile end at the same time, the middle tube 602 of the grouting inner tube 6 of appropriate length is selected, and it is stacked and connected with the top tube 601 by bolts 607 to achieve the length of the grouting pipeline. The combined and connected grouting inner tube 6 is lowered so that the inner tube grouting ports 604 correspond to the spherical pressure chambers 502 at the specified positions respectively. The grouting range of the inner tube grouting ports 604 covers the space size of the spherical pressure chamber 502. The cement slurry is pressed into the top tube 601 and transported to the multiple grouting closed pressure chambers formed by the inflatable airbag 605 after gas supply and expansion and tightly fitting with the grouting outer tube 5. Under the action of high pressure, it is ejected from the grouting ports on the pile side and pile end, thereby achieving the effect of simultaneous open grouting on the pile side and pile end.
[0060] See also Figure 9 If only open grouting is performed on the pile end, it is only necessary to select a top pipe 601 of the grouting inner pipe 6 of appropriate length and send it to the spherical pressure chamber 502 at the end of the pile body. Similarly, the inflatable airbag 605 is inflated and tightly fitted with the grouting outer pipe 5 to form a grouting closed pressure chamber. The cement slurry is only ejected through the slurry outlet at the pile end, thereby achieving the effect of open grouting only on the pile end.
[0061] See also Figure 8If grouting is only performed on the designated position on the pile side, the top pipe 601, the middle pipe 602 and the bottom pipe 603 of the grouting inner pipe 6 are stacked and connected by bolts 607 to achieve the length of the grouting pipeline. The inner pipe grouting outlet 604 corresponds to the spherical pressure chamber 502 at the designated position of the pile body. After the inflatable airbag 605 is expanded, it fits tightly with the grouting outer pipe 5 to form multiple grouting closed pressure chambers. The grouting inner pipe bottom pipe 603 is a solid pipe fitting used as a grouting pipe, thereby achieving the effect of grouting only the designated position on the pile side. Example
[0062] During the construction process using the device of the present invention, the following steps are adopted during the grouting construction process:
[0063] The first step: after the soil around the pile is consolidated to a stable state, a suitable grouting inner pipe 6 is installed, and open grouting is performed simultaneously through the open grouting pipe 5011 of the pile side transverse grouting pipe 501 and the pile end transverse grouting pipe 404. The cement slurry is pressed into the closed pressure chamber composed of the inflatable air bag 605 and the grouting outer pipe 5 through the grouting inner pipe 6, and is ejected from the grouting outlets on the pile side and the pile end; at the beginning, the slurry is in a mixed state with the soil around the pile and at the pile end, and the cement slurry is hydraulically injected into the gaps in the granular soil, gradually replacing and discharging the air and water therein, cementing the soil particles together, and enhancing the strength and anti-seepage ability of the soil; under the action of the pump slurry pressure, the cement slurry on the pile side seeps back along the pile body, further wraps and covers the pile body, fully fills the weak mud skin layer between the pile body and the soil layer, and further enhances the friction resistance of the pile body;
[0064] The second step is to disassemble and reassemble the grouting inner tube 6, and grout the soft soil layers of the pile end and the pile body separately; under the action of the grouting pressure, the grout and the soil around the pile end perform alternating effects such as penetration, filling, compaction, and splitting, and the slurry gradually replaces the soil within the grouting range to form a spherical enlarged head at the pile end. When the grouting pressure is further increased, the soil is further hydraulically split, and multiple network-like slurry veins are formed at the pile end, further enhancing the pile end bearing capacity and pile side friction resistance; then, the grouting inner tube combination mode is changed again, and the hollow closed grouting chamber 301 of the pile side closed grouting device 3 is grouted, and the capsule expands accordingly, compacting the soil around the pile, and finally forming a "dart-shaped" enlarged head;
[0065] Step 3: Open grouting is performed on the pile side and pile end again to fill the hollow part formed by grouting with the closed grouting device on the pile side.
[0066] The above combined grouting effect is shown in Figure 13 and Figure 14 Area A is the cement grouting reinforcement area on the pile side, and area B is the pile end expansion head formed by the cement slurry at the pile end.
[0067] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.
Claims
1. A combined post-grouting device for ring-rib prestressed pipe piles, characterized by: The invention comprises a ring-ribbed prestressed pipe pile body (1), a steel pile cap (2), a pile side closed grouting device (3), a cast iron conical pile tip (4), a grouting outer tube (5) and a grouting inner tube (6) which cooperate with each other, wherein the steel pile cap (2) is fitted on the upper end of the ring-ribbed prestressed pipe pile body (1), the cast iron conical pile tip (4) is connected to the lower end of the ring-ribbed prestressed pipe pile body (1), and the pile body is prefabricated with the pile side closed grouting device (3) and the grouting outer tube (5) arranged throughout the entire pile body; A fixed sleeve (201) is provided inside the steel pile cap (2), the fixed sleeve (201) is sleeve-connected to the upper end of the grouting outer pipe (5), and lateral support members (202) are connected around the fixed sleeve (201); Each pile side closed grouting device (3) is provided with three hollow closed grouting chambers (301) wrapped with rubber capsules. The hollow closed grouting chambers (301) are evenly arranged at equal angles in a dart shape in the pile side closed grouting device (3). The hollow closed grouting chambers (301) of two adjacent pile side closed grouting devices (3) are arranged at a cross-angle. The grouting outer tube (5) further comprises a pile side transverse grouting tube (501) and a spherical pressure chamber (502), the grouting outer tube (55) being connected to the pile side transverse grouting tube (501) via the spherical pressure chamber (502), the pile side transverse grouting tube (501) comprising an open grouting tube (5011) and a closed grouting tube (5012), the open grouting tube (5011) and the closed grouting tube (5012) on the same pile side grouting section being staggered and uniformly distributed in a spoke-like manner along the radial direction of the ring-rib-shaped prestressed pipe pile body (1), and the open grouting tubes (5011) on different pile side grouting sections being distributed at a cross-angle; An open grouting pipe (5011) is connected to a side of the pile body and an open grouting outlet (503) is provided. A disc-shaped permeable stone (504) is wrapped with filling cotton on the side and embedded in the open grouting outlet (503). The diameters of the permeable stone (504) and the open grouting outlet (503) are adapted to each other. The grouting inner tube (6) is arranged in the grouting outer tube (5), which includes a top tube (601), a middle tube (602) and a bottom tube (603) connected in sequence. The connection between the top tube (601) and the middle tube (602), and the connection between the middle tube (602) and the bottom tube (603) are both provided with an inner tube slurry outlet (604). An inflatable air bag (605) is provided above and below the inner tube slurry outlet (604), respectively. An air pipe (606) connected to the inflatable air bag (605) is arranged close to the outer wall of the grouting inner tube (6). The inflated inflatable air bag (605) is arranged close to the inner wall of the grouting outer tube (5), so that a closed pressure chamber is formed inside the grouting outer tube (5), and the slurry outlet range of the inner tube slurry outlet (604) covers the space size of the spherical pressure chamber (502); The cast iron conical pile tip (4) comprises a cone body (401), which is connected to the ring-rib prestressed pipe pile body (1) through a pile tip connector (402), a pile end grouting ring pipe (403) and a group of pile end transverse grouting pipes (404) are provided in the cone body, the pile end transverse grouting pipe (404) is connected to the spherical pressure chamber (502) of the grouting outer pipe (5), a horizontal grouting ring pipe outlet (405) is provided at the connection between the pile end transverse grouting pipe (404) and the pile end grouting ring pipe (403), a group of inclined pile end grouting side pipes (406) are connected below the pile end grouting ring pipe (403), and each pile end grouting ring pipe (403) is provided with a horizontal grouting ring pipe outlet (405). A group of grouting side pipe outlets (407) are provided on each grouting side pipe (406), the diameter of the grouting ring pipe outlet (405) is smaller than the diameter of the grouting side pipe outlet (407), the axis of the pile end grouting side pipe (406) is inclined at an angle of 60° to the horizontal plane of the pile end grouting ring pipe (403), and the spacing between two adjacent pile end grouting side pipes (406) is the same, and corresponding soil guide separation ribs (408) are provided below the pile end grouting side pipe (406), which are fixed on the cone body (401), and the circumferential range of the soil guide separation ribs (408) is greater than the diameter length of the pile end grouting side pipe (406).
2. The combined post-grouting device for annular rib-shaped prestressed pipe piles according to claim 1 is characterized in that: The ring-rib-shaped prestressed pipe pile body (1) is provided with a group of convex ring ribs (101), which are horizontally arranged at intervals of 1 to 3 m along the outer wall of the pile body, and the top pipe (601) and the middle pipe (602) of the grouting inner pipe (6), as well as the middle pipe (602) and the bottom pipe (603) are connected and assembled respectively by bolts (607), and the positions of the bolts (607) are staggered with the positions of the pile side transverse grouting pipes (501).
3. The combined post-grouting device for annular rib prestressed pipe piles according to claim 1 or 2, characterized in that: The inner diameter and outer diameter of the pile side closed grouting device (3) are respectively the same as the inner diameter and outer diameter of the ring-rib-shaped prestressed pipe pile body (1).
4. A construction method for the combined post-grouting device for annular ribbed prestressed pipe piles according to claim 1, comprising the following steps, characterized in that: Step 1: The pile body (1) of the ring-ribbed prestressed pipe pile is manufactured by using a prestressing process and a centrifugal forming method, and a pile side closed grouting device (3) and a grouting outer pipe (5) arranged throughout the entire pile body are prefabricated in the pile body, and a grouting inner pipe (6) is arranged inside the grouting outer pipe (5); Step 2: Fitting the steel pile cap (2) onto the upper end of the ring-ribbed prestressed pipe pile body (1) to protect the pile head of the ring-ribbed prestressed pipe pile from being damaged when the pile is sunk by hammering, and welding the cast iron conical pile tip (4) to the ring-ribbed prestressed pipe pile body (1) via the pile tip connector (402); Step 3: The grouting inner tube (6) is tightly connected by stacking threaded connectors. The diameter of the grouting inner tube (6) is smaller than the diameter of the grouting outer tube (5). The grouting inner tube (6) can be flexibly moved up and down in the grouting outer tube (5) according to the different grouting positions on the pile side. When grouting is carried out, the grouting outlet (604) of the inner tube is moved to the desired grouting position, and the inflatable air bag (605) is inflated through the air pipe (606) arranged on the outer wall of the grouting inner tube (6), so that a closed pressure chamber is formed in the grouting outer tube (5), thereby grouting the designated position; Step 4: After the prestressed pipe pile is delivered to the soil layer at the designed depth, the cement slurry is pumped into the grouting inner pipe (6) by a high-pressure pump on the ground, and is transmitted to the closed pressure chamber composed of the grouting inner pipe (6), the inflatable air bag (605) and the grouting outer pipe (5), and is sent to the grouting outlet through the prefabricated pile side and pile end grouting pipes and ejected out.
5. The construction method of the combined post-grouting device for annular rib-shaped prestressed pipe piles according to claim 4 is characterized in that: In the step 3, if open grouting is performed on the pile side and the pile end at the same time, a middle pipe (602) of the grouting inner pipe of suitable length is selected and stacked and connected with the top pipe (601) by bolts to achieve the length of the grouting pipe; if open grouting is performed only on the pile end, it is only necessary to select a top pipe (601) of suitable length and send it to the spherical pressure chamber at the end of the pile body; if grouting is performed only on the designated position of the pile side, the top pipe (601), the middle pipe (602) and the bottom pipe (603) are stacked and connected by bolts to achieve the length of the grouting pipe.
6. The construction method of the combined post-grouting device for annular rib-shaped prestressed pipe piles according to claim 4 is characterized in that: During the pipe pile construction process, if the pipe pile encounters a hard soil layer when being hammered into the soil, the pile sinking process is temporarily stopped first, and a grouting inner tube (6) is selected to grout only the pile end. A high-pressure water source is pressed into the grouting inlet of the grouting inner tube (6) at the top of the pile body, so that the high-pressure water source is ejected from the horizontal grouting ring tube grouting outlet (405) and the lateral grouting side tube grouting outlet (407) to soften the soil layer at the pile end, so that the pipe pile can pass smoothly when encountering a hard interlayer. After the water injection pressure value drops sharply and the water pressure value is maintained for several minutes, the prefabricated pipe pile is sunk again.
7. The construction method of the combined post-grouting device for annular rib-shaped prestressed pipe piles according to claim 4 is characterized in that: During the closed grouting process, the hollow closed grouting chamber (301) of the pile side closed grouting device (3) is controlled by the grouting pressure and the grouting amount. When the grouting amount or the grouting pressure meets the design requirements, the grouting is stopped. After the cement in the hollow closed grouting chamber (301) is solidified, a permanent dart-shaped cement body can be formed on the pile side of the prestressed pipe pile, thereby enhancing the bearing capacity of the prestressed pipe pile.
8. The construction method of the combined post-grouting device for annular rib-shaped prestressed pipe piles according to claim 4 is characterized in that: The open grouting pipe (5011) on the side of the pile is also used as a drainage pipe for the prefabricated pipe pile. During the static pressure pile sinking process in a deep soft soil foundation, due to the soil squeezing effect of the pile sinking, the soft clay around the pile will generate a higher pore water pressure under the action of squeezing and disturbance. The pore water in the soil layer around the pile is filtered into the grouting outer pipe (5) through the permeable stone (504), and then the pore water in the grouting outer pipe (5) is pumped out by the surface water pump, thereby reducing the stress increment and excess pore water pressure generated during the pile sinking process, thereby effectively reducing the damage of the soil squeezing effect to the project.
9. The construction method of the combined post-grouting device for annular rib-shaped prestressed pipe piles according to claim 4, characterized in that: In the step 4, during the post-grouting process, the pile body (1) of the ring-ribbed prestressed pipe pile is first subjected to open grouting on the pile side and pile end. When grouting liquid emerges from the ground at the pile top, the grouting is stopped. The combined connection mode of the grouting inner tube (6) is reassembled, and the pile end and the local weak soil layer on the pile side are grouted separately. Then, the hollow closed grouting chamber (301) in the closed grouting device (3) on the pile side is grouted to form a dart-shaped expansion joint ring. Finally, the pile side open grouting is performed to fill the hollow part caused by the grouting and compacting of the soil layer by the closed grouting device.