A pile delivery device for pile pressing

Abstract

The utility model discloses a pile feeding device for pile pressing, which is connected with the top of a prefabricated pile foundation at the bottom, and then the pile foundation is sent into the soil to a specified depth and then disconnected. The bottom of the device is provided with a heating device and a cooling cavity, and the cooling cavity is connected with a cooling medium adding device on the ground through a cooling medium injection pipe. The heating device expands the bottom of the device to strengthen the connection when the device is connected, and the bottom of the device shrinks to facilitate disconnection when the device is disconnected by injecting a cooling medium such as liquid nitrogen. The device has two connection modes: one is that an inner threaded sleeve pipe is arranged on the top of the prefabricated pile foundation, and an outer thread is arranged on the bottom of the device; the other is that an annular end head plate with an L-shaped rotary insertion slot is fixed on the upper end surface of the prefabricated pile foundation, and a rotary buckle that is matched with the insertion slot is arranged on the lower end surface of the device. The device solves the problem that the traditional connection mode cannot be rigidly connected in vibration or high-frequency free resonance hammer construction, and improves the construction efficiency and quality.

Description

Technical Field

[0001] This utility model relates to the field of infrastructure construction, specifically to a pile driving device for pile driving. Background Technology

[0002] In pile foundation construction, the connection method between the pile driver and the pile foundation directly affects construction efficiency and quality. The traditional method involves inserting the sleeve at the lower end of the pile driver into the top of the pile foundation. However, if a rigid connection cannot be achieved between the pile driver and the top of the pile foundation, high-frequency non-resonant hammers cannot be used for pile driving, limiting construction efficiency and applicability. Especially under vibration or high-frequency non-resonant hammer construction conditions, traditional methods struggle to meet the rigid connection requirements, leading to difficulties in pile driving and impacting project progress and quality. Utility Model Content

[0003] To address this problem, this invention proposes a method for connecting a pile driving rod and a casing based on the principle of thermal expansion and contraction. This method involves pre-embedding a heating device at the bottom of the pile driving rod, utilizing thermal expansion to allow the lower end of the rod to expand and tightly fix itself to the casing, achieving an efficient and reliable connection. After the pile is driven to the predetermined elevation, a cooling medium such as dry ice or liquid nitrogen is injected, utilizing the principle of thermal contraction to cause the pile driving rod to shrink and loosen from the casing, thus allowing for rapid removal of the pile driving rod. This invention effectively solves the problem of the inability to rigidly connect the pile driving rod to the pile foundation during vibration or high-frequency non-resonant hammer construction, improving construction efficiency and quality, and has broad application prospects. The specific solution of this invention is as follows:

[0004] A pile driving device for pile driving, wherein the bottom of the pile driving device is integrally connected to the top of a precast pile foundation, and the connection between the pile driving device and the precast pile foundation is disconnected after the precast pile foundation is driven into the soil to a specified depth; wherein...

[0005] The precast pile foundation is provided with an internal threaded sleeve at the top, the pile driving device is provided with an external thread at the bottom, the pile driving device is provided with a heating device at the bottom and a cooling cavity is provided on the inner side of the bottom, and the cooling cavity is connected to the cooling medium adding device on the ground through a cooling medium injection pipe.

[0006] After the pile driving device is connected to the precast pile foundation, the bottom of the pile driving device is expanded by a heating device to strengthen the connection with the precast pile foundation, and the bottom of the pile driving device is contracted by injecting a cooling medium into the cooling cavity to facilitate disconnection from the precast pile foundation.

[0007] Furthermore, the pile driving device is an annular sleeve, and the heating device is a spiral resistance wire that is attached to the inner wall of the pile driving device.

[0008] The cooling cavity is located inside the bottom side wall of the pile driving device. The inner wall of the pile driving device is provided with a through hole connected to the cooling cavity. One end of the cooling medium injection pipe is connected to the through hole, and the other end is connected to the cooling medium adding device.

[0009] Furthermore, the cooling medium is liquid nitrogen.

[0010] This utility model also provides another pile driving device for pile driving, wherein the bottom of the pile driving device is detachably connected to the top of the precast pile foundation via a rotating buckle; wherein...

[0011] The precast pile foundation has an annular end plate fixed to its upper surface, and the annular end plate has four L-shaped rotating slots distributed around its circumference.

[0012] The lower end face of the pile driving device is coaxially fixed with a rotating buckle that engages with the annular end plate. The rotating buckle includes a hollow sleeve and strip buckles distributed circumferentially on the outer wall of the hollow sleeve. After the strip buckles are inserted into the rotating slot, they rotate circumferentially to fix the pile driving device to the precast pile foundation.

[0013] The rotating buckle is equipped with a heating device and a cooling chamber is provided in the side wall of the hollow sleeve. The cooling chamber is connected to the cooling medium adding device on the ground through a cooling medium injection pipe.

[0014] After the pile driving device is connected to the precast pile foundation, the rotating buckle is expanded by the heating device to strengthen the connection with the precast pile foundation, and the bottom of the rotating buckle is contracted by injecting cooling medium into the cooling cavity to facilitate disconnection from the precast pile foundation.

[0015] Furthermore, the pile driving device is an annular sleeve, and the heating device is a spiral resistance wire that fits against the inner wall of the hollow sleeve.

[0016] The cooling cavity is located inside the side wall of the hollow sleeve. The inner wall of the pile driving device is provided with a through hole connected to the cooling cavity. One end of the cooling medium injection pipe is connected to the through hole, and the other end is connected to the cooling medium adding device.

[0017] Furthermore, the cooling medium is liquid nitrogen.

[0018] The main technical advantages of this pile driving device are as follows:

[0019] 1. Reliable connection and easy disassembly: The bottom of the pile driving device expands through the heating device and is tightly fixed to the precast pile foundation, resulting in high connection strength; after the pile driving is completed, liquid nitrogen and other cooling media are injected to shrink the bottom, making it easy to disconnect the connection without complicated operations.

[0020] 2. Adaptable to various construction scenarios: It provides two connection methods, threaded connection and rotary snap-fit ​​connection, to adapt to different precast pile foundation structures, especially suitable for vibration or high-frequency non-resonance hammer construction, breaking through the limitations of traditional connection.

[0021] 3. Improve construction efficiency: Utilize the principle of thermal expansion and contraction to achieve rapid connection and separation, reduce downtime, avoid the difficulties of driving piles in traditional rigid connections, and significantly improve the efficiency of pile driving construction.

[0022] 4. Simple structure and easy maintenance: It adopts a modular design with ring sleeve and spiral resistance wire, which is compact in structure and has a reasonable layout of cooling chamber and pipeline, making it easy to install and maintain. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the pile driving device being connected to the precast pile foundation via a threaded connection in Embodiment 1 of this utility model;

[0025] Figure 2 This is a schematic diagram of a precast pile foundation with an internally threaded sleeve at the top, as shown in Embodiment 1 of this utility model.

[0026] Figure 3 This is a schematic diagram of a pile-driving device with external threads at the bottom and a heating device inside, as shown in Embodiment 1 of this utility model.

[0027] Figure 4 This is a schematic diagram of the spiral heating device in Embodiment 1 of this utility model;

[0028] Figure 5 This is a cross-sectional view of the pile-driving device with a cooling cavity in Embodiment 1 of this utility model;

[0029] Figure 6 This is a vertical sectional view of the bottom of the pile driving device in Embodiment 1 of this utility model;

[0030] Figure 7 This is a schematic diagram of the pile driving device being connected to the precast pile foundation using a rotating buckle method in Embodiment 2 of this utility model;

[0031] Figure 8 This is a schematic diagram of a precast pile foundation with an annular end plate at the top, as shown in Embodiment 2 of this utility model.

[0032] Figure 9 This is a schematic diagram of a pile-driving device with a rotating buckle at the bottom, as shown in Embodiment 2 of this utility model. Detailed Implementation

[0033] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with the present invention.

[0034] To fully understand this utility model, detailed steps and structures will be presented in the following description to illustrate the technical solution of this utility model. Preferred embodiments of this utility model are described in detail below; however, in addition to these detailed descriptions, this utility model may have other embodiments.

[0035] Example 1

[0036] like Figure 1-6 As shown, the pile driving device 2 adopts a ring-shaped metal sleeve structure, with a standard external threaded connector 4 machined at its bottom, forming an initial mechanical connection with the internal threaded sleeve 3 pre-embedded at the top of the precast pile foundation 1. During installation, the pile driving device 2 is screwed into the top of the pile foundation manually or mechanically to ensure that the thread engagement depth meets the design requirements, thus forming a preliminary fixation. This connection method utilizes the axial limiting characteristics of the thread and can withstand a certain vertical load, but it is prone to loosening due to thread clearance under vibration conditions. Therefore, a heating device is needed to further strengthen the connection.

[0037] The external threaded connector 4, as a key connecting component, integrates a dual-function heating and cooling module.

[0038] Heating device: A spiral resistance wire is used, which is tightly fitted to the inner wall of the connector and connected to the ground power supply through a high-temperature resistant wire. After the resistance wire is energized, the temperature of the connector can be raised by 100-200℃ within 10-30 seconds, causing the metal material to expand thermally, increasing the diameter of the external thread by 2-5mm, filling the tiny gap between the external thread and the internal thread sleeve 3, and forming an interference fit.

[0039] Cooling chamber 5: Designed as an annular cavity, distributed circumferentially around the external threaded joint 4, with a volume of approximately 0.5-1L. The chamber is connected to the cooling medium injection pipe on the inner wall of the pile driving device 2 through a through hole with a diameter of 8-12mm. The other end of the pipe is connected to a liquid nitrogen storage tank on the ground, which can quickly complete the filling of the chamber in a short time.

[0040] The main body of the pile driving device 2 is a ring-shaped sleeve made of seamless steel pipe. The inner wall is precision machined to ensure that the spiral heating resistance wire 7 fits tightly, reducing heat conduction loss. The resistance wire is wrapped with a high-temperature resistant insulating layer (such as ceramic fiber) to prevent short circuits or leakage. The wall thickness design of the cooling chamber 5 is designed to ensure structural strength while facilitating rapid heat conduction. The cooling medium injection pipe uses a flexible metal hose, which has vibration resistance and low-temperature resistance characteristics and can withstand the sudden temperature drop (-196℃) when liquid nitrogen flows.

[0041] After the pile driving device 2 completes the initial threaded connection with the pile foundation, the ground power switch is turned on, and the spiral resistance wire 7 is energized and heated. The heat is quickly conducted to the external threaded joint 4 through the metal sleeve. The external threaded joint 4 expands after being heated to eliminate thread gaps and generate interference pressure, increasing the connection strength by 3-5 times. The heating process is monitored in real time by a temperature sensor, and the power is automatically cut off after the set temperature is reached. Subsequently, the pile driver applies an axial load (usually 500-2000kN) to drive the pile foundation into the soil layer to the design elevation.

[0042] After the pile driving operation is completed, the cooling medium adding device injects liquid nitrogen and other cooling media 6 into the cooling chamber 5 inside the external threaded joint 4 through the cooling medium injection pipe, which quickly reduces the temperature of the external threaded joint 4 and causes the external threaded joint 4 to shrink. Then, by rotating the pile driving device 2 in the opposite direction, the connection between the pile driving device 2 and the precast pile foundation 1 can be easily disconnected. The precast pile foundation 1 remains in the soil, and the pile driving device 2 is used for other purposes.

[0043] Example 2

[0044] Example 2 is optimized for vibration conditions, employing a composite connection method combining mechanical snap-fit ​​and thermal expansion reinforcement. For example... Figure 7-9 As shown, the bottom of the pile driving device 2 is connected to the precast pile foundation 1 by a rotating buckle. An annular end plate 8 is welded to the upper surface of the precast pile foundation 1, with four L-shaped rotating slots 81 evenly distributed around its circumference. A rotating buckle 9 is fixed to the bottom of the pile driving device 2. The rotating buckle 9 includes a hollow sleeve 91 coaxially fixed to the lower surface of the pile driving device 2 (the outer diameter of the hollow sleeve 91 is smaller than the outer diameter of the precast pile foundation 1). Four strip-shaped buckles 92 are provided on the outer wall of the hollow sleeve 91 (the width matches the L-shaped rotating slots 81 and corresponds one-to-one with the positions of the four L-shaped rotating slots).

[0045] The annular end plate 8 is fixed to the pile foundation by welding. The vertical section of the L-shaped rotating slot 81 is used to guide the insertion of the snap-fit, and the horizontal section is used for rotation locking. During installation, the pile-driving device 2 is lowered vertically, the hollow sleeve 91 is fitted onto the top of the pile foundation, the strip snap-fit ​​92 is aligned with the vertical section of the slot and inserted to the bottom, and then the pile-driving device 2 is driven to rotate 90° clockwise by the hydraulic rotating mechanism. The strip snap-fit ​​92 slides along the horizontal section of the slot and finally snaps into the end of the slot, forming a mechanical lock (similar to the rotation lock of a socket and plug). This process can be completed within 1 minute, without the need for precise alignment of the threads, and the installation efficiency is significantly higher than that of threaded connections.

[0046] The hollow sleeve 91 of the rotating buckle 9 also integrates a spiral heating resistance wire 7 on its inner wall, with a power density slightly higher than that of the threaded connection, to meet faster heating requirements. A cooling chamber 5 is provided inside the hollow sleeve 91, and the cooling chamber 5 is connected to a cooling medium adding device on the ground through a cooling medium injection pipe.

[0047] After the rotation locking is completed, the heating resistance wire 7 is activated, and the temperature of the hollow sleeve 91 rises rapidly. The hollow sleeve 91 and the strip-shaped buckle 92 expand accordingly, tightly pressing against the inner hole of the annular end plate 8 and the inner wall of the L-shaped rotating slot 81, forming a dual locking mechanism of thermal expansion and mechanical clamping. During pile driving, the pile driving device 2 evenly transfers the load of the pile driver to the pile foundation, avoiding the stress concentration problem of traditional insertion-type connections. The heating process is monitored in real time by a temperature sensor, and the power is automatically cut off after the set temperature is reached. Subsequently, the pile driver applies an axial load, pressing the pile foundation into the soil layer to the design elevation.

[0048] After the pile driving operation is completed, the cooling medium adding device injects liquid nitrogen and other cooling media 6 into the cooling chamber 5 inside the hollow sleeve 91 through the cooling medium injection pipe, which quickly reduces the temperature of the hollow sleeve 91, causing the rotating buckle 9 to contract. Then, the pile driving device 2 can be rotated in the opposite direction to easily disconnect the connection between the pile driving device 2 and the precast pile foundation 1. The precast pile foundation 1 remains in the soil, and the pile driving device 2 is used for other purposes.

[0049] The preferred embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above. Devices and structures not described in detail herein should be understood as being implemented in a conventional manner within the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this utility model using the disclosed methods and techniques, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. This does not affect the essential content of this utility model. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model, without departing from the content of the technical solution of this utility model, still fall within the protection scope of the technical solution of this utility model.

Claims

1. A pile driving device for pile driving, characterized in that, The bottom of the pile driving device is detachably connected to the top of the precast pile foundation via threads; wherein... The precast pile foundation is provided with an internal threaded sleeve at the top, the pile driving device is provided with an external thread at the bottom, the pile driving device is provided with a heating device at the bottom and a cooling cavity is provided on the inner side of the bottom, and the cooling cavity is connected to the cooling medium adding device on the ground through a cooling medium injection pipe. After the pile driving device is connected to the precast pile foundation, the bottom of the pile driving device is expanded by a heating device to strengthen the connection with the precast pile foundation, and the bottom of the pile driving device is contracted by injecting cooling medium into the cooling cavity to facilitate disconnection from the precast pile foundation.

2. The pile driving device as described in claim 1, characterized in that, The pile driving device is an annular sleeve, and the heating device is a spiral resistance wire that is attached to the inner wall of the pile driving device. The cooling cavity is located inside the bottom side wall of the pile driving device. The inner wall of the pile driving device is provided with a through hole connected to the cooling cavity. One end of the cooling medium injection pipe is connected to the through hole, and the other end is connected to the cooling medium adding device.

3. The pile driving device as described in claim 1, characterized in that, The cooling medium is liquid nitrogen.

4. A pile driving device for pile driving, characterized in that, The bottom of the pile driving device is detachably connected to the top of the precast pile foundation via a rotating buckle; wherein... The precast pile foundation has an annular end plate fixed to its upper surface, and the annular end plate has four L-shaped rotating slots distributed around its circumference. The lower end face of the pile driving device is coaxially fixed with a rotating buckle that engages with the annular end plate. The rotating buckle includes a hollow sleeve and strip buckles distributed circumferentially on the outer wall of the hollow sleeve. After the strip buckles are inserted into the rotating slot, they rotate circumferentially to fix the pile driving device to the precast pile foundation. The rotating buckle is equipped with a heating device and a cooling chamber is provided in the side wall of the hollow sleeve. The cooling chamber is connected to the cooling medium adding device on the ground through a cooling medium injection pipe. After the pile driving device is connected to the precast pile foundation, the rotating buckle is expanded by the heating device to strengthen the connection with the precast pile foundation, and the bottom of the rotating buckle is contracted by injecting cooling medium into the cooling cavity to facilitate disconnection from the precast pile foundation.

5. The pile driving device as described in claim 4, characterized in that, The pile driving device is an annular sleeve, and the heating device is a spiral resistance wire that fits against the inner wall of the hollow sleeve. The cooling cavity is located inside the side wall of the hollow sleeve. The inner wall of the pile driving device is provided with a through hole connected to the cooling cavity. One end of the cooling medium injection pipe is connected to the through hole, and the other end is connected to the cooling medium adding device.

6. The pile driving device as described in claim 4, characterized in that, The cooling medium is liquid nitrogen.

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