A support structure for a pipe jacking working shaft and its construction method

Abstract

This invention discloses a support structure and construction method for a pipe jacking shaft, comprising pile rows and internal supports. The pile rows are prestressed pipe piles, arranged according to the cross-sectional shape of the pipe jacking shaft to form support piles. A cap beam is installed on the top of each prestressed pipe pile to press and fix it in place. Multiple internal supports are horizontally arranged along the height of the shaft within the support piles, pressing against the prestressed pipe piles. Furthermore, multiple crawling devices are installed between the internal supports and the support piles to enable the internal supports to move along the height of the shaft. This invention features high component reuse rate, low construction cost, and short construction period.

Description

Technical Field

[0001] This invention relates to pipe jacking engineering, specifically to a support structure for a pipe jacking working shaft and its construction method. Background Technology

[0002] Pipe jacking is a pipeline installation technique that involves little or no excavation. In pipe jacking, the jacking force generated by jacking equipment within a working shaft overcomes the friction between the pipe and the surrounding soil, pushing the pipe into the ground at a designed slope, and then removing the excavated soil. After one section of pipe is pushed into the soil, the second section is lowered and the jacking continues. The principle is to use the thrust from the main jacking cylinder and intermediate sections (such as the pipe section and the relay section) to advance the tool pipe or tunneling machine from the working shaft through the soil until it is lifted into the receiving shaft. The pipeline follows closely behind the tool pipe or tunneling machine, and is buried between the working shaft and the receiving shaft.

[0003] The working shaft is a crucial component of pipe jacking construction. Construction of the working shaft typically employs either the caisson method or the excavation method with foundation pit support. The caisson method suffers from high costs and slow construction speed, and it easily disturbs the surrounding soil, potentially causing building subsidence and cracking. The foundation pit support method requires the construction of a support structure before excavation, saving time and costs. However, when the surrounding environment of the working shaft is complex, the excavation depth is large, or the geological conditions are poor, a more reliable and rigid support method is needed to ensure the safety of the working shaft support structure and the surrounding environment. Considering both construction costs and safety, the commonly used support type is currently pile foundation + internal bracing. The pile foundation typically uses cast-in-place concrete piles, while the internal bracing generally uses concrete slabs or beams. This type of support involves complex construction procedures, including rotary drilling, reinforcement cage binding and hoisting, beam reinforcement binding, formwork installation, and concrete pouring. These procedures significantly impact the construction period and increase costs. Furthermore, the support components are almost always disposable, resulting in low reuse rates. Therefore, it is very important to develop a support structure for pipe jacking working wells that is low in cost and easy to construct. Summary of the Invention

[0004] The technical problem to be solved by this invention is that, in view of the shortcomings of the existing concrete cast-in-place pile + concrete internal support structure used in pipe jacking working shafts, which has complex construction procedures and inconvenience, this invention provides a low-cost and convenient pipe jacking working shaft support structure and its construction method.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A support structure for a pipe jacking shaft includes a row of piles and internal supports. The piles are prestressed pipe piles, and each prestressed pipe pile is arranged according to the cross-sectional shape of the pipe jacking shaft to form a support pile. A cap beam for pressing and fixing the prestressed pipe pile is installed on the top of the prestressed pipe pile. Multiple internal supports are arranged inside the support pile along the height direction of the shaft. The internal supports press against the prestressed pipe piles, and multiple crawling devices for enabling the internal supports to crawl along the height direction of the shaft are installed between the internal supports and the support piles.

[0007] Preferably, the cap beam includes a first truss, the bottom of which is arranged with a pile sleeve corresponding to the number of prestressed pipe piles, the pile sleeve being fitted onto the top of the prestressed pipe piles and fixed with fasteners.

[0008] Preferably, the internal support includes a second truss, and the outer periphery of the second truss is arranged with cylinders that are the same number as the number of prestressed pipe piles. The telescopic end of the cylinder is equipped with a stop for securing the prestressed pipe pile, so as to press the prestressed pipe pile tightly through the stop.

[0009] Preferably, a main air intake pipe is installed on the second truss, which connects to the air intake pipes of each cylinder. This allows for unified air intake and exhaust of each cylinder, facilitating operation, ensuring uniform stress on each prestressed concrete pile, and allowing control of the prestressing force applied to the prestressed concrete pile by adjusting the gas pressure.

[0010] Preferably, a positioning plate is fixedly installed on the outer periphery of the second truss, and a movable plate is slidably installed on the positioning plate. The cylinder is installed on the movable plate, so that the position of the cylinder can be adjusted by sliding the movable plate on the positioning plate, thereby making the pressing position of the cylinder consistent with the center position of the corresponding prestressed pipe pile. This not only ensures that the prestressed pipe pile is subjected to uniform force, but also that the pressure of the prestressed pipe pile is evenly transmitted to the cylinder.

[0011] Preferably, the stop block includes a first wedge block and a second wedge block arranged opposite to each other. The first wedge block is fixedly installed, and the second wedge block is movably installed on the telescopic end of the cylinder via an adjusting bolt, so as to facilitate adjustment of the stop block according to the diameter of different prestressed pipe piles, so that the stop block fits better with the prestressed pipe pile, achieving stable support and uniform force transmission.

[0012] Preferably, the crawling device includes a track groove installed between adjacent prestressed pipe piles and a crawling assembly installed between the track groove and the second truss.

[0013] Preferably, the crawling assembly includes a rack arranged on the track groove, a gear meshing with the rack, and a motor for driving the gear. The motor is fixedly mounted on the second truss via a motor mount, and the motor is a brake motor.

[0014] Preferably, the middle part of the crown beam and the inner support is hollowed out to form an operating space, so as to facilitate the excavation of soil in the working well through the operating space.

[0015] Based on the same inventive concept, the present invention also provides a construction method utilizing the aforementioned pipe jacking well support structure, comprising:

[0016] (1) Before the construction of the pipe jacking working shaft, prestressed pipe piles are constructed. After all the prestressed pipe piles are constructed and the support piles are formed, a certain depth is excavated on both the inner and outer sides of the support piles, and the capping beam is installed on the top of the support piles formed by the prestressed pipe piles. The capping beam is hoisted as a whole during installation.

[0017] (2) After the crown beam is installed, continue to excavate the soil inside the support pile to a certain depth and then install the first inner support. After the first inner support is installed, continue to excavate the soil. When the excavation reaches the position of the second inner support, install the second inner support. Repeat this process until all inner supports are installed. The inner supports are installed by overall hoisting.

[0018] (3) A crawling device is installed between the internal support and the support pile formed by the prestressed pipe pile.

[0019] The support structure for the pipe jacking working shaft of this invention features high component reuse rate, low construction cost, and short construction period, specifically manifested in:

[0020] (1) The piles of this invention use prestressed pipe piles. Prestressed pipe piles are not only fast to construct and simple to construct, but can also be pulled out and reused after the backfilling is completed in the pipe jacking working well, which can effectively reduce construction costs.

[0021] (2) The capping beam and internal support of this invention both adopt a circular arc truss structure. This structure has high strength and rigidity, can withstand large loads, and also has the advantages of high recyclability, light weight, and convenient installation and dismantling. At the same time, the capping beam and internal support of this invention can be directly hoisted to the site for installation. After installation, the earthwork can be excavated immediately (traditional concrete internal supports require the concrete to reach a certain age before excavation, which affects the construction period). After the construction of the working well is completed, it can also be easily dismantled as a whole (if concrete capping beam and internal support are used, the dismantling of concrete capping beam and internal support will damage the prestressed pipe piles, making it difficult to completely recycle the prestressed pipe piles). In addition, the internal support can be moved up and down by a climbing device. The hollow structure in the middle makes the internal support occupy less space in the working well, and can provide more space for construction materials and construction machinery to enter and exit the working well.

[0022] (3) The internal support of the present invention can adapt to working wells of different diameters by adjusting the length of the support rod (i.e., the extension and retraction of the cylinder). The support rod is made of a cylinder with a gas pre-pressurization device, which can pre-force the prestressed pipe pile construction. The magnitude of the pre-force is also easy to adjust, which can effectively constrain the horizontal displacement of the support pile and ensure the stability and safety of the working well.

[0023] (4) During the excavation of the working well, the stress on the support piles will change. The internal support of this invention can move up and down, and its support position can be adjusted at any time according to the stress on the support piles. When a dangerous situation occurs in the working well, if adjusting the support position of the internal support is no longer effective in restraining the displacement of the working well, the stability of the working well can be ensured by quickly increasing the number of internal supports because the installation process of the internal support is simple. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of the support structure for the pipe jacking working well of the present invention.

[0026] Figure 2 This is a schematic diagram of the structure of the crown beam of the present invention.

[0027] Figure 3 This is a schematic diagram of the internal support structure of the present invention.

[0028] Figure 4 This is a diagram of the air passage structure on the internal support of the present invention.

[0029] Figure 5 This is a schematic diagram of the crawling device of the present invention.

[0030] Figure 6 This is a schematic diagram illustrating the structure and operating principle of the crawling component of the present invention.

[0031] In the picture:

[0032] 1. Prestressed concrete pipe piles;

[0033] 2. Crown beam; 21. First truss; 22. Pipe pile sleeve; 23. Fasteners;

[0034] 3. Internal support; 31. Second truss; 32. Cylinder; 33. Stop block; 331. First wedge block; 332. Second wedge block; 333. Adjusting bolt; 34. Main air intake pipe; 35. Positioning plate; 36. Movable plate; 37. Air pipe; 38. Air intake pipe;

[0035] 4. Crawling device; 41. Track groove; 42. Crawling assembly; 421. Rack; 422. Gear; 423. Motor; 424. Motor mount;

[0036] 5. Pipe jacking working shaft. Detailed Implementation

[0037] The present invention will be further described below with reference to specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, 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; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] Please see Figure 1 An embodiment of the support structure for the pipe jacking working shaft of the present invention mainly consists of prestressed pipe piles 1, capping beams 2, internal supports 3, and crawling devices 4. The prestressed pipe piles 1 are arranged according to the cross-sectional shape of the pipe jacking working shaft 5 to form support piles. A capping beam 2 for pressing and fixing the prestressed pipe piles 1 is installed on the top of the support piles. Multiple internal supports 3 are arranged along the height direction of the working shaft inside the support piles. The internal supports 3 press against each of the prestressed pipe piles 1, and multiple crawling devices 4 are installed between the internal supports 3 and the support piles to enable the internal supports 3 to crawl along the height direction of the working shaft.

[0041] Please see Figure 2The cap beam 2 includes a first truss 21, the bottom of which is arranged with pile sleeves 22 in the same number as the prestressed pipe piles 1. The pile sleeves 22 are fitted onto the top of each prestressed pipe pile 1 and fixed with fasteners 23. In this embodiment, the fasteners 23 are preferably clamping screws.

[0042] Please see Figure 3 , Figure 4 The inner support 3 includes a second truss 31, with cylinders 32 arranged around its outer periphery in a number consistent with the number of prestressed pipe piles 1. The telescopic ends of the cylinders 32 are fitted with stops 33 for securing the prestressed pipe piles 1. Each stop 33 includes a first wedge 331 and a second wedge 332 arranged opposite each other. The first wedge 331 is fixedly installed, while the second wedge 332 is movably installed at the telescopic end of the cylinder 32 via adjusting bolts 333. A main air inlet pipe 34 is installed on the second truss 31, and the main air inlet pipe 34 is connected to the air inlet pipes 38 of each cylinder 32 via air pipes 37. The main air inlet pipe 34, air pipes 37, and air inlet pipes 38 are preferably elastically telescopic air pipes.

[0043] To facilitate the stable clamping of the prestressed concrete pipe pile 1 by the stop block 33, a positioning plate 35 is fixedly installed on the outer periphery of the second truss 31, and a movable plate 36 is slidably installed on the positioning plate 34. The cylinder 32 is installed on the movable plate 36. In this way, the cylinder 32 and the stop block 33 can be adjusted in position as needed so that the stop block 33 fits precisely against the outer surface of the prestressed concrete pipe pile 1.

[0044] Please see Figure 5 , Figure 6 The crawling device 4 includes multiple track grooves 41 installed between adjacent prestressed pipe piles 1 and crawling components 42 installed between the track grooves 41 and the second truss 31. The crawling component 42 includes a rack 421 arranged on the track groove 41, a gear 422 meshing with the rack 421, and a motor 423 for driving the gear 422. The motor 423 is fixedly installed on the second truss 31 via a motor mount 424, and the motor 423 is a brake motor.

[0045] The working principle of the support structure for the pipe jacking working shaft of this invention is as follows: During the excavation of the pipe jacking working shaft, significant earth pressure is generated. This earth pressure is borne by the prestressed pipe piles 1 (support piles). The prestressed pipe piles 1 transmit the earth pressure to the cylinders 32 of the inner support 3. The increased air pressure within the cylinders 32 provides supporting force to the prestressed pipe piles 1, thereby constraining soil deformation and ensuring safety during the excavation of the working shaft. The specific construction steps using this invention are as follows:

[0046] (1) Before the construction of the pipe jacking working shaft 5, surveying and setting out should be carried out to mark the specific position of each prestressed pipe pile 1. Then, the prestressed pipe pile 1 should be constructed using the hammer driving method or the static pressure method. The overall outer contour of the support structure of the pipe jacking working shaft of the present invention is preferably circular. After all the prestressed pipe piles 1 have been constructed, after excavating to a certain depth on both the inner and outer sides of the pipe jacking working shaft, the capping beam 2 should be installed on the top of the prestressed pipe piles 1. The first truss 21 of the capping beam 2 is preferably a circular arc pipe truss structure welded together from steel plates and steel pipes.

[0047] Installation method of cap beam 2: The cap beam 2 is equipped with pipe pile sleeves 22 in the same number as the prestressed pipe piles 1. After the cap beam 2 is lifted as a whole by a crane on site, the pipe pile sleeves 22 are aligned with each prestressed pipe pile 1 and then slowly lowered so that each prestressed pipe pile 1 enters the pipe pile sleeve 22. Then, the pipe pile sleeves 22 are fixed together with the prestressed pipe piles 1 by fasteners 23 (clamping screws).

[0048] (2) After the cap beam 2 is installed, continue excavating the earth to a certain depth and then install the first inner support 3. After the first inner support 3 is installed, the earth can be excavated to continue. When the excavation reaches the position of the second inner support 3, the second inner support 3 can be installed. The second truss 31 of the inner support 3 is preferably a circular arc tube truss structure composed of welded steel pipes. The specific installation elevation and quantity of the inner support 3 shall be calculated and confirmed by the design unit.

[0049] Installation method of internal support 3: Cylinders 32 are evenly arranged on the outer periphery of the second truss 31 of the internal support 3. The air inlet pipe 38 of the cylinder 32 is connected through the air pipe 37, and the main air inlet pipe 34 is set on the air pipe 37. This air inlet method of the cylinder is conducive to the unified air intake and exhaust of the cylinder 32, making the operation convenient, the force on each prestressed pipe pile 1 is uniform, and the prestressing force applied to the prestressed pipe pile 1 by the cylinder 32 can be controlled by controlling the gas pressure. The cylinder 32 pushes the stop 33 at its telescopic end to tighten the prestressed pipe pile 1, thereby constraining the displacement of the prestressed pipe pile 1.

[0050] When installing the inner support 3, the entire inner support 3 is hoisted into the jacking shaft 5. The cylinder 32 is fixed on the movable plate 36. The movable plate 36 moves left and right on the positioning plate 35 to adjust the position of the cylinder 32 so that the cylinder 32 is aligned with the center of the prestressed pipe pile 1. This ensures that the prestressed pipe pile 1 is subjected to uniform force and that the soil pressure on the prestressed pipe pile 1 is evenly transmitted to the cylinder 32. The movable second wedge block 332 is adjusted according to the diameter of the prestressed pipe pile 1 using the adjusting bolt 333 to match the diameter of the corresponding prestressed pipe pile 1. (Note: Since the diameter of each jacking shaft and the diameter or spacing of the prestressed pipe piles may vary, the support rod of the prestressed pipe pile 1 is set as a cylinder 32 to accommodate shafts of different diameters. The movable plate 36 and adjusting bolt 333 are set to accommodate prestressed pipe piles 1 of different diameters or spacings.)

[0051] (3) Crawling device

[0052] In order to adjust the vertical position of the inner support 3, crawling devices 4 are evenly arranged in the four directions of the inner support 3. The track groove 41 of the crawling device 4 needs to be installed in sequence according to the excavation of the pipe jacking working shaft. The track groove 41 is fixed to the prestressed pipe piles 1 on both sides by screws. A rack 421 is arranged in the track groove 41. The vertical movement of the inner support 3 is realized by the meshing transmission of the gear 422 and the rack 421.

[0053] The motor 423 of the crawling device 4 is preferably a brake motor because it has a locking function. When the inner support 3 moves to the designated position, the motor 423 stops starting and locks the transmission shaft through the brake inside the motor 423, so that the gear 422 is locked in the rack 421, realizing the self-locking of the inner support 3, ensuring that the inner support 3 does not move in the designated position, and preventing the inner support 3 from falling into the jacking shaft and causing a safety accident.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present invention, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A support structure for a pipe jacking shaft, comprising piles and internal bracing, characterized in that, The piles are prestressed pipe piles, and each prestressed pipe pile is arranged according to the cross-sectional shape of the jacking shaft to form a support pile. A cap beam for pressing and fixing the prestressed pipe pile is installed on the top of the prestressed pipe pile. Multiple inner supports are arranged horizontally along the height direction of the working shaft inside the support pile. The inner supports press against the prestressed pipe pile, and multiple crawling devices for enabling the inner supports to crawl along the height direction of the working shaft are installed between the inner supports and the support pile. The internal support includes a second truss, and cylinders with the same number of prestressed pipe piles are arranged around the outer periphery of the second truss. The telescopic end of the cylinder is equipped with a stop for securing the prestressed pipe pile. A main air intake pipe is installed on the second truss, and the main air intake pipe is connected to the air intake pipe of each of the cylinders; A positioning plate is fixedly installed on the outer periphery of the second truss, and a movable plate is slidably installed on the positioning plate, with the cylinder mounted on the movable plate.

2. The support structure for the pipe jacking working shaft according to claim 1, characterized in that, The cap beam includes a first truss, at the bottom of which are arranged pipe pile sleeves of the same number as the prestressed pipe piles. The pipe pile sleeves are fitted onto the top of the prestressed pipe piles and fixed with fasteners.

3. The support structure for the pipe jacking working shaft according to claim 1, characterized in that, The stop block includes a first wedge block and a second wedge block arranged opposite to each other. The first wedge block is fixedly installed, and the second wedge block is movably installed at the telescopic end of the cylinder via an adjusting bolt.

4. The support structure for the pipe jacking working shaft according to claim 1, characterized in that, The crawling device includes a track groove installed between adjacent prestressed pipe piles and a crawling assembly installed between the track groove and the second truss.

5. The support structure for the pipe jacking working shaft according to claim 4, characterized in that, The crawling assembly includes a rack arranged on the track groove, a gear meshing with the rack, and a motor for driving the gear. The motor is fixedly mounted on the second truss via a motor mount, and the motor is a brake motor.

6. The support structure for the pipe jacking working shaft according to claim 1, characterized in that, The central hollowed-out portion of the crown beam and the inner support forms an operating space.

7. A construction method using the support structure for a pipe jacking working shaft as described in any one of claims 1-6, characterized in that... include: (1) Before the construction of the pipe jacking working shaft, prestressed pipe piles are constructed. After all the prestressed pipe piles are constructed and the support piles are formed, a certain depth is excavated on both the inner and outer sides of the support piles, and the cap beam is installed on the top of the support piles formed by the prestressed pipe piles. The cap beam is hoisted as a whole during installation. (2) After the crown beam is installed, continue to excavate the soil inside the support pile to a certain depth and then install the first inner support. After the first inner support is installed, continue to excavate the soil. When the excavation reaches the position of the second inner support, install the second inner support. Repeat this process until all inner supports are installed. The inner supports are installed by overall hoisting. (3) A crawling device is installed between the internal support and the support pile formed by the prestressed pipe pile.

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