A shotcrete device for post-grouting of precast piles

Abstract

This utility model provides a grouting device for post-grouting of precast piles, including a pressure cap, a valve sleeve, a nozzle structure, a piston assembly, an elastic reset device, a pressure-relieving telescopic rod, and a dynamic sealing assembly. The upper part of the pressure cap is threaded to the precast pile, and the lower part of the pressure cap is threaded to the top of the valve sleeve. A grouting through hole is provided in the middle of the pressure cap. The bottom outer wall of the valve sleeve has a conical structure, and the nozzle structure is located on the side wall of the valve sleeve. The grouting device for post-grouting of precast piles described in this utility model solves the problems of complex grouting device structures and inability to overcome the pressure blockage of grouting pipes caused by the soil squeezing effect of precast piles in related technologies, which lead to poor engineering applicability, high failure rate, and inability to guarantee effective grouting.

Description

Technical Field

[0001] This utility model belongs to the field of precast pile construction technology, and in particular relates to a grouting device for post-grouting of precast piles. Background Technology

[0002] Precast pile technology, with its highly standardized quality resulting from industrialized production, significantly shortened construction cycle due to rapid pile driving, and substantial reduction in on-site pollution from factory-based manufacturing, has become a core solution for modern pile foundation engineering and is widely applicable to various building and infrastructure projects. However, in complex and varied geological structures, traditional pile driving techniques struggle to accurately stimulate the potential resistance at the pile tip and sides, and the pile-soil interface interaction mechanism is not yet fully understood. Consequently, a gap remains between its theoretical bearing capacity and actual engineering performance, indicating that this potential is not fully realized.

[0003] Existing technologies include high-pressure jet grouting pile core insertion, deep mixing pile core insertion, and grouting after hole enlargement and pile driving to improve pile foundation bearing capacity. Although these methods have achieved some results, they often fail to gain widespread adoption due to the need for multiple equipment, complex construction processes, low efficiency, or excessive costs. Furthermore, the grouting devices in these technologies are complex in structure and cannot overcome the sealing problems caused by the precast pile soil squeezing effect, such as device locking failure, grouting pipe pressure blockage, soil reverse intrusion, and grout backflow. These issues result in poor engineering applicability, high failure rate, and inability to guarantee effective grouting. Summary of the Invention

[0004] In view of this, the present invention aims to at least partially solve one of the related technical problems.

[0005] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0006] A shotcrete device for post-grouting of precast piles includes a pressure cap, a valve sleeve, a spray hole structure, a piston assembly, an elastic reset device, a pressure-relieving telescopic rod, and a dynamic sealing assembly.

[0007] The upper part of the pressure cap is threadedly connected to the precast pile, the lower part of the pressure cap is threadedly connected to the top of the valve body sleeve, and the middle part of the pressure cap is provided with a grouting through hole;

[0008] The bottom outer wall of the valve body sleeve has a conical structure, and the spray hole structure is provided on the side wall of the valve body sleeve;

[0009] The piston assembly and the elastic reset device are both disposed inside the valve body sleeve. The piston assembly is slidably disposed inside the valve body sleeve. The bottom of the piston assembly is connected to the pressure-relieving telescopic rod. The pressure-relieving telescopic rod passes through the bottom of the valve body sleeve. One end of the elastic reset device abuts against the piston assembly, and the other end of the elastic reset device abuts against the bottom of the inner side of the valve body sleeve.

[0010] The piston assembly engages with the inner wall of the valve body sleeve via the dynamic sealing assembly;

[0011] In the un-grouted state, the elastic reset device pushes the piston assembly upward to block the grouting hole;

[0012] When the grouting pressure reaches the opening threshold, the piston assembly is pressed down and compresses the elastic reset device, so that the grouting hole is connected to the grouting through hole.

[0013] Furthermore, the piston assembly includes a first piston block, a second piston block, a pressure sensor, and two first telescopic rod assemblies. The pressure sensor is disposed between the first piston block and the second piston block. The bottom of the second piston block is connected to the pressure-relieving telescopic rod. Both the first piston block and the second piston block are slidably engaged with the inner wall of the valve body sleeve through a dynamic sealing assembly. The first piston block is connected to the second piston block through the two first telescopic rod assemblies.

[0014] Furthermore, the elastic reset device includes four elastic telescopic components, which are evenly distributed between the piston assembly and the bottom inner side of the valve body sleeve. The top of each elastic telescopic component is connected to the piston assembly, and the bottom of each elastic telescopic component is connected to the bottom inner side of the valve body sleeve.

[0015] Furthermore, the elastic telescopic assembly includes a first return spring and a second telescopic rod assembly. The top of the second telescopic rod assembly is connected to the bottom of the second piston block, and the bottom of the second telescopic rod assembly is connected to the bottom of the inner side of the valve body sleeve. The first return spring is sleeved on the outside of the second telescopic rod assembly.

[0016] Furthermore, the elastic reset device is a second reset spring, which is placed inside the valve body sleeve and its two ends respectively abut against the lower surface of the piston assembly and the bottom surface of the valve body sleeve.

[0017] Furthermore, the dynamic sealing assembly includes a first sealing ring, a second sealing ring, and an annular baffle. The first sealing ring is disposed on the outside of the first piston block, the second sealing ring is disposed on the outside of the second piston block, and the annular baffle is disposed at the bottom of the second piston block. The annular baffle can prevent the first sealing ring and the second sealing ring from falling off.

[0018] Furthermore, the piston assembly is a one-piece piston block.

[0019] Furthermore, the spray hole structure includes four grouting holes, which are evenly distributed on the side wall of the valve body sleeve.

[0020] Compared with existing technologies, the shotcrete device for post-grouting of precast piles described in this utility model has the following advantages:

[0021] 1. This technology fundamentally solves the technical pain points of traditional precast pile post-grouting processes, such as grouting device jamming, grouting hole blockage, and uncontrolled grout return caused by soil squeezing effect. The conical bottom structure of the valve sleeve, combined with an elastic reset device, ensures that the piston assembly can tightly seal the grouting hole in the non-grouting state, completely preventing soil intrusion. When the grouting pressure reaches the preset threshold, the piston assembly's two-stage telescopic structure (the first and second piston blocks are linked by a pressure sensor) can dynamically respond to pressure changes. The displacement of the pressure-relieving telescopic rod precisely controls the opening of the grouting hole, avoiding sealing failure caused by sudden pressure changes and achieving uniform grout injection. In addition, the dynamic sealing component adopts a layered sealing ring and anti-detachment baffle combination design, maintaining high-pressure sealing during piston reciprocating motion, completely eliminating the risk of grout backflow or external mud and sand infiltration.

[0022] 2. The four grouting holes evenly distributed on the side wall of the valve body sleeve, combined with the symmetrical layout of the elastic telescopic components, effectively disperse the grouting impact force and prevent component deformation caused by local stress concentration. The integrated design of the pressure sensor further enables real-time monitoring of the grouting process, providing a mechanical feedback basis for precise control of grouting parameters. This structural solution, integrating dynamic sealing, pressure buffering, and multi-channel injection functions, not only significantly improves the grouting success rate and pile foundation reinforcement effect but also greatly reduces the probability of maintenance downtime due to device failure, meeting the comprehensive requirements of modern pile foundation engineering for efficiency, durability, and intelligence. Attached Figure Description

[0023] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0024] Figure 1 This is a schematic diagram of a shotcrete device for post-grouting of precast piles, as described in an embodiment of this utility model.

[0025] Figure 2 This is a cross-sectional view of the shotcrete device described in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the dynamic sealing assembly described in an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100, gland; 200, valve body sleeve; 210, grouting hole; 220, threaded structure; 300, pressure-relieving telescopic rod; 400, piston assembly; 410, first piston block; 420, second piston block; 500, elastic telescopic assembly; 510, first sealing ring; 520, second sealing ring; 530, annular baffle. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0030] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] A shotcrete device for post-grouting of precast piles, such as Figure 1 As shown, it includes a pressure cap 100, a valve body sleeve 200, a spray hole structure, a piston assembly 400, an elastic reset device, a pressure-relieving telescopic rod 300, and a dynamic sealing assembly; the upper part of the pressure cap 100 is threadedly connected to the precast pile, the lower part of the pressure cap 100 is threadedly connected to the top of the valve body sleeve 200, and the middle part of the pressure cap 100 is provided with a grouting through hole.

[0034] The bottom outer wall of the valve body sleeve 200 has a conical structure, and the spray hole structure is set on the side wall of the valve body sleeve 200; the spray hole structure includes 4 grouting holes 210, which are evenly distributed on the side wall of the valve body sleeve 200.

[0035] Both the piston assembly 400 and the elastic reset device are located inside the valve body sleeve 200. The piston assembly 400 is slidably disposed inside the valve body sleeve 200. The bottom of the piston assembly 400 is connected to the pressure-relieving telescopic rod 300, which penetrates the bottom of the valve body sleeve 200. One end of the elastic reset device abuts against the piston assembly 400, and the other end abuts against the bottom of the inner side of the valve body sleeve 200. The piston assembly 400 cooperates with the inner wall of the valve body sleeve 200 through a dynamic sealing assembly. This fundamentally solves the technical pain points in the traditional precast pile post-grouting process, such as grouting device jamming, grouting hole blockage, and uncontrolled grout return caused by soil squeezing effect. The conical bottom structure of the valve body sleeve 200, combined with an elastic reset device, ensures that the piston assembly 400 can tightly seal the grouting hole in the non-grouting state, completely preventing soil intrusion. When the grouting pressure reaches the preset threshold, the two-stage telescopic structure of the piston assembly 400 (the first piston block 410 and the second piston block 420 are linked by a pressure sensor) can dynamically respond to pressure changes. The displacement of the pressure-relieving telescopic rod 300 precisely controls the opening of the grouting hole, avoiding sealing failure caused by sudden pressure changes and achieving uniform grout spraying. In addition, the dynamic sealing assembly adopts a layered sealing ring and anti-detachment baffle combination design, maintaining high-pressure sealing during piston reciprocating motion, completely eliminating the risk of grout backflow or external mud and sand infiltration.

[0036] In the un-grouted state, the elastic reset device pushes the piston assembly 400 upward to block the grouting hole; when the grouting pressure reaches the opening threshold, the piston assembly 400 is pressed downward and compresses the elastic reset device, so that the grouting hole is connected to the grouting through hole.

[0037] The four grouting holes evenly distributed on the side wall of the valve body sleeve 200, combined with the symmetrical layout of the elastic telescopic component 500, effectively disperse the grouting impact force and prevent component deformation caused by local stress concentration. The integrated design of the pressure sensor further enables real-time monitoring of the grouting process, providing a mechanical feedback basis for precise control of grouting parameters. This structural solution, integrating dynamic sealing, pressure buffering, and multi-channel injection functions, not only significantly improves the grouting success rate and pile foundation reinforcement effect but also greatly reduces the probability of maintenance downtime due to device failure, meeting the comprehensive requirements of modern pile foundation engineering for efficiency, durability, and intelligence.

[0038] The piston assembly 400 includes a first piston block 410, a second piston block 420, a pressure sensor, and two first telescopic rod assemblies. The pressure sensor is disposed between the first piston block 410 and the second piston block 420. The bottom of the second piston block 420 is connected to the pressure-relieving telescopic rod 300. Both the first piston block 410 and the second piston block 420 are slidably engaged with the inner wall of the valve body sleeve 200 through a dynamic sealing assembly. The first piston block 410 is connected to the second piston block 420 through the two first telescopic rod assemblies. The dynamic sealing assembly includes a first sealing ring 510, a second sealing ring 520, and an annular baffle 530. The first sealing ring 510 is disposed on the outside of the first piston block 410, the second sealing ring 520 is disposed on the outside of the second piston block 420, and the annular baffle 530 is disposed at the bottom of the second piston block 420. The annular baffle 530 can prevent the first sealing ring 510 and the second sealing ring 520 from falling off.

[0039] The elastic reset device includes four elastic telescopic components 500, which are evenly distributed between the piston assembly 400 and the bottom inner side of the valve body sleeve 200. The top of each elastic telescopic component 500 is connected to the piston assembly 400, and the bottom of each elastic telescopic component 500 is connected to the bottom inner side of the valve body sleeve 200. Each elastic telescopic component 500 includes a first reset spring and a second telescopic rod assembly. The top of the second telescopic rod assembly is connected to the bottom of the second piston block 420, and the bottom of the second telescopic rod assembly is connected to the bottom inner side of the valve body sleeve 200. The first reset spring is sleeved on the outside of the second telescopic rod assembly.

[0040] How this example works

[0041] Step 1: During the grouting preparation stage, the valve sleeve 200 (with a conical bottom structure) of the grouting device is connected to the pressure cap 100 by threaded fastening, and the grouting through hole at the upper end of the pressure cap 100 is connected to the grouting pipe pre-embedded in the reinforcing cage; then the pile is hoisted and driven as a whole. At this time, the elastic reset device (such as four evenly distributed elastic telescopic components 500 or an integral second reset spring) pushes the piston assembly 400 upward, so that the first piston block 410 tightly seals the four grouting holes on the side wall of the valve sleeve 200 through the dynamic sealing assembly, forming a physical isolation barrier to effectively resist the soil squeezing pressure and soil intrusion during the pile driving process.

[0042] Step 2: Post-grouting construction after pile positioning: High-pressure cement grout is injected into the through hole of the pressure cap 100 through the grouting pipe. When the pressure reaches the preset threshold, the grout pressure acts on the upper surface of the piston assembly 400. At this time, the dual-stage piston structure (the first piston block 410 and the second piston block 420 are linked by a pressure sensor and a telescopic rod, wherein the fixed part of the telescopic rod is built into the second piston block 420, and the telescopic part of the telescopic rod is placed outside between the first piston block 410 and the second piston block 420) moves downward under pressure, synchronously compressing the elastic reset device and driving the pressure-relieving telescopic rod 300 to slowly extend towards the soil at the pile end. As the piston assembly 400 moves downward, the grouting hole is connected to the inner cavity of the valve sleeve 200, and the grout is evenly sprayed radially towards the soil around the pile through the four evenly distributed grouting holes.

[0043] Step 3: During the grouting process, the layered sealing structure of the piston assembly 400 (the first and second sealing rings 520 are limited and prevented from detaching by the annular baffle 530) maintains the high-pressure dynamic sealing of the inner wall of the valve body sleeve 200, while the progressive compression characteristics of the elastic reset device release the soil reaction force through the pressure-relieving telescopic rod 300, ensuring the dynamic balance between the grouting hole opening and the grouting pressure; after the grouting is completed and the pressure decreases, the elastic reset device pushes the piston assembly 400 to reset and move upward, re-sealing the grouting hole and pulling up the pressure-relieving telescopic rod 300 to receive it, completely blocking the grout return channel and the risk of external soil backflow.

[0044] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A jet grouting device for post grouting of precast piles, characterized in that: It includes a gland (100), a valve body sleeve (200), a nozzle structure, a piston assembly (400), an elastic reset device, a pressure-relieving telescopic rod (300), and a dynamic sealing assembly; The upper part of the pressure cap (100) is threadedly connected to the precast pile, the lower part of the pressure cap (100) is threadedly connected to the top of the valve body sleeve (200), and the middle part of the pressure cap (100) is provided with a grouting through hole; The bottom outer wall of the valve body sleeve (200) has a conical structure, and the spray hole structure is provided on the side wall of the valve body sleeve (200); The piston assembly (400) and the elastic reset device are both disposed inside the valve body sleeve (200). The piston assembly (400) is slidably disposed inside the valve body sleeve (200). The bottom of the piston assembly (400) is connected to the pressure-relieving telescopic rod (300). The pressure-relieving telescopic rod (300) passes through the bottom of the valve body sleeve (200). One end of the elastic reset device abuts against the piston assembly (400), and the other end of the elastic reset device abuts against the bottom of the inner side of the valve body sleeve (200). The piston assembly (400) engages with the inner wall of the valve body sleeve (200) through the dynamic sealing assembly; in the non-grouting state, the elastic reset device pushes the piston assembly (400) upward to block the grouting hole; When the grouting pressure reaches the opening threshold, the piston assembly (400) is pressed down and compresses the elastic reset device, so that the grouting hole is connected to the grouting through hole.

2. A jet grouting device for post grouting of precast piles according to claim 1, characterized in that: The piston assembly (400) includes a first piston block (410), a second piston block (420), a pressure sensor, and two first telescopic rod assemblies. The pressure sensor is disposed between the first piston block (410) and the second piston block (420). The bottom of the second piston block (420) is connected to the pressure-relieving telescopic rod (300). Both the first piston block (410) and the second piston block (420) are slidably engaged with the inner wall of the valve body sleeve (200) through a dynamic sealing assembly. The first piston block (410) is connected to the second piston block (420) through two first telescopic rod assemblies.

3. A jet grouting device for post grouting of precast piles according to claim 2, characterized in that: The elastic reset device includes four elastic telescopic components (500), which are evenly distributed between the piston assembly (400) and the bottom inner side of the valve body sleeve (200). The top of the elastic telescopic component (500) is connected to the piston assembly (400), and the bottom of the elastic telescopic component (500) is connected to the bottom inner side of the valve body sleeve (200).

4. A device for post-grouting of precast piles according to claim 3, characterized in that: The elastic telescopic assembly (500) includes a first return spring and a second telescopic rod assembly. The top of the second telescopic rod assembly is connected to the bottom of the second piston block (420), and the bottom of the second telescopic rod assembly is connected to the bottom of the inner side of the valve body sleeve (200). The first return spring is sleeved on the outside of the second telescopic rod assembly.

5. A device for post-grouting of precast piles according to claim 2, characterized in that: The elastic reset device is a second reset spring, which is placed inside the valve body sleeve (200) and its two ends respectively abut against the lower surface of the piston assembly (400) and the inner bottom surface of the valve body sleeve (200).

6. A device for post-grouting of precast piles according to any one of claims 2-5, characterized in that: The dynamic sealing assembly includes a first sealing ring (510), a second sealing ring (520), and an annular baffle (530). The first sealing ring (510) is disposed on the outside of the first piston block (410), the second sealing ring (520) is disposed on the outside of the second piston block (420), and the annular baffle (530) is disposed at the bottom of the second piston block (420). The annular baffle (530) can prevent the first sealing ring (510) and the second sealing ring (520) from falling off.

7. A device for post-grouting of precast piles according to claim 1, characterized in that: The piston assembly (400) is a one-piece piston block.

8. A device for post-grouting of precast piles according to claim 6, characterized in that: The nozzle structure includes four grouting holes (210), which are evenly distributed on the side wall of the valve body sleeve (200).

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