Pipe jacking working well supporting structure and construction method thereof

Abstract

The invention discloses a pipe-jacking working well supporting structure and a construction method thereof.The pipe-jacking working well supporting structure comprises row piles and inner supports, the row piles are prestressed pipe piles, the prestressed pipe piles are arranged according to the shape of the cross section of a pipe-jacking working well to form supporting piles, and top beams used for pressing and fixing the prestressed pipe piles are installed at the tops of the prestressed pipe piles; a plurality of inner supports are horizontally arranged in the supporting piles in the height direction of the working well, the inner supports abut against the prestressed pipe piles, and a plurality of crawling devices used for achieving crawling of the inner supports in the height direction of the working well are installed between the inner supports and the supporting piles. The member is high in repeated utilization rate, low in construction cost and short in construction period.

Description

Technical Field

[0001] The invention relates to a pipe jacking project, and in particular to a pipe jacking working well support structure and a construction method thereof. Background Art

[0002] Pipe jacking construction is a pipeline burial construction technology that does not involve excavation or requires minimal excavation. Pipe jacking construction is to use the jacking force generated by the jacking equipment in the working well to overcome the friction between the pipeline and the surrounding soil, push the pipeline into the soil according to the designed slope, and transport the soil away. After one section of the pipe is pushed into the soil layer, the second section of the pipe is pushed in. The principle is to use the thrust of the main jacking cylinder and the pipeline room, relay room, etc. to push the tool pipe or tunnel boring machine from the working well through the soil layer and lift it into the receiving well. The pipeline follows the tool pipe or tunnel boring machine and is buried between the working well and the receiving well.

[0003] The working well of pipe jacking is an important part of pipe jacking construction. The working well construction usually adopts the caisson method or the foundation pit support excavation method. The caisson method has the disadvantages of high cost and slow construction speed, and it is easy to disturb the surrounding soil and cause the building to sink and crack. When the foundation pit support excavation method is adopted, the support structure needs to be constructed before excavation. This method can save construction time and cost. However, when the surrounding environment of the working well is complex, the excavation depth is large, and the geological conditions are poor, in order to ensure the safety of the working well support structure and the surrounding environment, a more reliable and rigid support method needs to be adopted. Considering the construction cost and safety, the commonly used support type is pile row + internal support. The pile row generally adopts concrete cast-in-place piles, and the internal support generally adopts concrete slabs or beams. The construction process of this support type includes rotary drilling, steel cage binding and hoisting, beam steel bar binding, formwork installation, concrete pouring, etc. The construction process is complicated, which seriously affects the construction period and increases the construction cost. In addition, its support components are almost all disposable and have a low reuse rate. Therefore, it is very important to develop a low-cost, easy-to-construct pipe jacking work shaft support structure. Summary of the invention

[0004] The technical problem to be solved by the present invention is that, in view of the shortcomings of the existing jacking pipe working shaft adopted concrete cast-in-place piles + concrete inner support support structure, which has complex construction procedures and inconvenient construction, the present invention provides a jacking pipe working shaft support structure with low cost and convenient construction and a construction method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A supporting structure for a jacking pipe working shaft comprises a pile row and an inner support, wherein the pile row adopts prestressed pipe piles, and each prestressed pipe pile is arranged according to the cross-sectional shape of the jacking pipe working shaft to form a supporting pile, and a crown beam for pressing and fixing the prestressed pipe pile is installed on the top of the prestressed pipe pile, and a plurality of inner supports are arranged inside the supporting pile along the height direction of the working shaft, and the inner support presses the prestressed pipe pile, and a plurality of crawling devices for realizing the crawling of the inner support along the height direction of the working shaft are installed between the inner support and the supporting pile.

[0007] Preferably, the crown beam comprises a first truss, the bottom of which is arranged with pipe pile sleeves whose number is the same as the prestressed pipe piles, and the pipe pile sleeves are sleeved on the tops of the prestressed pipe piles and fixed with fasteners.

[0008] Preferably, the inner support comprises a second truss, the outer periphery of which is arranged with cylinders whose number is the same as the prestressed pipe piles, and the telescopic ends of the cylinders are provided with blocks for clamping the prestressed pipe piles so as to tighten the prestressed pipe piles through the blocks.

[0009] Preferably, a main air intake pipe is installed on the second truss, and the main air intake pipe is connected to the air intake pipes of each cylinder. In this way, each cylinder can realize unified air intake and exhaust, which is convenient to operate, and each prestressed pipe pile is evenly stressed. Moreover, the prestressing force applied by the cylinder to the prestressed pipe pile can be controlled by controlling the size of the gas pressure.

[0010] Preferably, a positioning plate is fixedly installed on the outer periphery of the second truss, a movable plate is slidably installed on the positioning plate, and 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 tightening position of the cylinder consistent with the center position of the corresponding prestressed pipe pile, not only the prestressed pipe pile is evenly stressed, but also the pressure of the prestressed pipe pile can be evenly transferred to the cylinder.

[0011] Preferably, the block includes a first wedge block and a second wedge block that are relatively arranged, the first wedge block is fixedly installed, and the second wedge block is movably installed on the telescopic end of the cylinder through an adjusting bolt, so as to facilitate the adjustment of the block according to the diameters of different prestressed pipe piles, so that the block and the prestressed pipe piles can fit better, thereby achieving stable support and uniform force transmission.

[0012] Preferably, the crawling device comprises 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 seat, and the motor is a brake motor.

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

[0015] Based on the same inventive concept, the present invention also provides a construction method using the pipe jacking working shaft support structure, which comprises:

[0016] (1) Prestressed pipe piles are constructed before the construction of the pipe jacking working pit. After all prestressed pipe piles are constructed and support piles are formed, a certain depth is excavated on both 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;

[0017] (2) After the crown beam is installed, continue to excavate the earth inside the support pile to a certain depth and then install the first inner support. After installing the first inner support, continue to excavate the earth downward immediately. When the excavation reaches the position of the second inner support, install the second inner support. Repeat this process until all the inner supports are installed. The inner supports are installed in an integral hoisting manner.

[0018] (3) A crawling device is provided between the inner support and the supporting piles formed by the prestressed pipe piles.

[0019] The supporting structure for the pipe jacking work pit of the present invention has a high component reuse rate, low construction cost and short construction period, which is specifically manifested in the following aspects:

[0020] (1) The pile row of the present invention adopts prestressed pipe piles. The prestressed pipe piles not only have a fast construction speed and a simple construction process, but also can be pulled out and reused after the jacking work pit is backfilled, which can effectively reduce the construction cost.

[0021] (2) The crown beam and inner support of the present invention both adopt a circular arc tube truss structure, which has high strength and rigidity, can withstand large loads, and also has the advantages of high recycling rate, light weight, and convenient installation and removal. At the same time, the crown beam and inner support of the present invention can be directly hoisted to the site for installation, and the earthwork can be excavated immediately after the installation is completed (the traditional concrete inner support needs to wait until the concrete reaches a certain age before excavation, which affects the construction period), and it can also be simply dismantled as a whole after the construction of the working well is completed (if a concrete crown beam and inner support are used, the prestressed pipe piles will be damaged during the removal of the concrete crown beam and inner support, making it difficult to completely recycle the prestressed pipe piles), and the inner support can be moved up and down by a climbing device, and the middle part adopts a hollow structure, so that the inner support occupies less space in the working well, which 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), and its support rod adopts a cylinder with a gas pre-stressing device, which can pre-stress the prestressed pipe piles during construction, and the size of the pre-stressing force can also be easily adjusted, which can effectively restrain the horizontal displacement of the support piles and ensure the stability and safety of the working well.

[0023] (4) During the excavation of the working pit, the stress conditions of the support piles will change, and the internal support of the present invention can move up and down, and its support position can be adjusted at any time according to the stress conditions of the support piles. When a dangerous situation occurs in the working pit, if the displacement of the working pit cannot be effectively restrained by adjusting the support position of the internal support, the stability of the working pit can be ensured by quickly increasing the number of internal supports, because the installation process of the internal support is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of the overall structure of the supporting structure of the jacking working shaft of the present invention.

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

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

[0028] Figure 4 This is a diagram of the gas path structure on the inner support of the present invention.

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

[0030] Figure 6 It is a schematic diagram of the structure and action principle of the crawling component of the present invention.

[0031] In the figure:

[0032] 1. Prestressed pipe piles;

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

[0034] 3. Inner support; 31. Second truss; 32. Cylinder; 33. Stopper; 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 seat;

[0036] 5. Pipe jacking working well. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0038] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] See also Figure 1 , an embodiment of the support structure of the jacking working well of the present invention is mainly composed of prestressed pipe piles 1, crown beams 2, inner supports 3, crawling devices 4, etc. If the prestressed pipe piles 1 are arranged according to the cross-sectional shape of the jacking working well 5 to form support piles, the top of the support piles is installed with a crown beam 2 for pressing and fixing the prestressed pipe piles 1, and multiple inner supports 3 are arranged in the support piles along the height direction of the working well. The inner supports 3 press against each of the prestressed pipe piles 1, and multiple crawling devices 4 for realizing the inner supports 3 crawling along the height direction of the working well are installed between the inner supports 3 and the support piles.

[0041] See also Figure 2The crown beam 2 includes a first truss 21, and the bottom of the first truss 21 is provided with a number of pipe pile sleeves 22 that is the same as the number of prestressed pipe piles 1. The pipe pile sleeves 22 are sleeved on the top of each prestressed pipe pile 1 and fixed with fasteners 23. In this embodiment, the fasteners 23 are preferably compression screws.

[0042] See also Figure 3 , Figure 4 The inner support 3 includes a second truss 31, and the outer periphery of the second truss 31 is arranged with cylinders 32 of the same number as the prestressed pipe piles 1, and the telescopic end of the cylinder 32 is installed with a stopper 33 for clamping the prestressed pipe piles 1. The stopper 33 includes a first wedge block 331 and a second wedge block 332 arranged opposite to each other, the first wedge block 331 is fixedly installed, and the second wedge block 332 is movably installed on the telescopic end of the cylinder 32 through an adjusting bolt 333. A main air intake pipe 34 is installed on the second truss 31, and the main air intake pipe 34 is connected to the air intake pipes 38 of each cylinder 32 through an air pipe 37. The main air intake pipe 34, the air pipe 37, and the air intake pipe 38 are preferably elastically retractable air pipes.

[0043] In order to facilitate the stopper 33 to firmly clamp the prestressed pipe pile 1, a positioning plate 35 is fixedly installed on the outer periphery of the second truss 31, a movable plate 36 is slidably installed on the positioning plate 34, and the cylinder 32 is installed on the movable plate 36. In this way, the position of the cylinder 32 and the stopper 33 can be adjusted as needed, so that the stopper 33 just fits the outer surface of the prestressed pipe pile 1.

[0044] See also Figure 5 , Figure 6 The crawling device 4 includes a plurality of track grooves 41 installed between adjacent prestressed pipe piles 1 and a crawling assembly 42 installed between the track grooves 41 and the second truss 31. The crawling assembly 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 seat 424, and the motor 423 is a brake motor.

[0045] The working principle of the supporting structure of the pipe jacking working well of the present invention is as follows: during the excavation of the pipe jacking working well, a large soil pressure will be generated, and the soil pressure will be borne by the prestressed pipe pile 1 (support pile). The prestressed pipe pile 1 transmits the soil pressure to the cylinder 32 of the inner support 3. After the air pressure in the cylinder 32 increases, it provides support force to the prestressed pipe pile 1, thereby restraining the deformation of the soil and ensuring the safety during the excavation of the working well. The specific construction steps of the present invention are as follows:

[0046] (1) Before the construction of the jacking working well 5, the survey and layout should be carried out, and the specific position of each prestressed pipe pile 1 should be marked. Then, the prestressed pipe pile 1 should be constructed by hammering or static pressure. The overall outer contour of the jacking working well support structure of the present invention is preferably circular. After all the prestressed pipe piles 1 are constructed, a certain depth is excavated on both sides of the jacking working well, and then the crown beam 2 is installed on the top of the prestressed pipe pile 1. The first truss 21 of the crown beam 2 preferably adopts a circular arc tube truss structure composed of a steel plate and a steel pipe welded together.

[0047] Installation method of the crown beam 2: The crown beam 2 is provided with pile sleeves 22 whose number is the same as the prestressed piles 1. After the crown beam 2 is hoisted as a whole by a crane on site, the pile sleeves 22 are aligned with each prestressed pile 1 and then slowly lowered to allow each prestressed pile 1 to enter the pile sleeves 22, and then the pile sleeves 22 are fixed together with the prestressed pile 1 by fasteners 23 (tightening screws).

[0048] (2) After the crown beam 2 is installed, continue to excavate the earth to a certain depth and then install the first inner support 3. After the first inner support 3 is installed, continue to excavate the earth downward immediately. 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 preferably adopts a circular arc tube truss structure composed of welded steel pipes. The installation elevation and installation quantity of the inner support 3 are specifically calculated and confirmed by the design unit.

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

[0050] When installing the inner support 3, the inner support 3 is hoisted into the jacking working pit 5 as a whole, and 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 just aligned with the center position of the prestressed pipe pile 1, so that the prestressed pipe pile 1 is evenly stressed and the soil pressure on the prestressed pipe pile 1 can be evenly transmitted to the cylinder 32. The movable second wedge block 332 is adjusted in position by adjusting the bolt 333 according to the diameter of the prestressed pipe pile 1 so that it matches the diameter of the corresponding prestressed pipe pile 1. (Note: Since the diameter of each jacking working pit, as well as the diameter or spacing of the prestressed pipe piles, is different, the support rod of the prestressed pipe pile 1 is set as the cylinder 32 to adapt to working pits of different diameters, and the movable movable plate 36 and adjusting bolt 333 are set to adapt to prestressed pipe piles 1 of different diameters or spacings.)

[0051] (3) Crawling device

[0052] In order to adjust the up and down position of the inner support 3, the crawling device 4 is evenly arranged in the four directions of the inner support 3. The installation of the track groove 41 of the crawling device 4 needs to be extended and installed in sequence according to the excavation of the jacking working pit. 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, and the up and down 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 preferably adopts a brake motor because it has a locking function. When the inner support 3 moves to the specified position, the motor 423 stops starting, and the transmission shaft is locked by the brake inside the motor 423, so that the gear 422 is stuck in the rack 421, thereby realizing self-locking of the inner support 3 and ensuring that the inner support 3 does not move at the specified position, thereby preventing the inner support 3 from falling in the jacking working shaft and causing a safety accident.

[0054] The above is only a specific implementation scheme of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the art can make many possible changes and modifications to the technical scheme of the present invention by using the technical content disclosed above without departing from the scope of the technical scheme of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical scheme of the present invention should fall within the protection scope of the technical scheme of the present invention.

Claims

1. A pipe jacking work pit support structure, comprising a pile row and an inner support, characterized in that: The row of piles adopts prestressed pipe piles, and each prestressed pipe pile is arranged according to the cross-sectional shape of the jacking working well to form a supporting pile. A crown beam for pressing and fixing the prestressed pipe pile is installed on the top of the prestressed pipe pile. A plurality of inner supports are horizontally arranged in the supporting pile along the height direction of the working well. The inner support presses the prestressed pipe pile, and a plurality of crawling devices for realizing the crawling of the inner support along the height direction of the working well are installed between the inner support and the supporting pile.

2. The pipe jacking work well support structure according to claim 1 is characterized in that: The crown beam comprises a first truss, the bottom of which is arranged with pipe pile sleeves having the same number as the prestressed pipe piles, the pipe pile sleeves being sleeved on the tops of the prestressed pipe piles and fixed with fasteners.

3. The pipe jacking work shaft support structure according to claim 1, characterized in that: The inner support comprises a second truss, the outer periphery of which is arranged with cylinders having the same number as the prestressed pipe piles, and the telescopic ends of the cylinders are provided with blocks for clamping the prestressed pipe piles.

4. The pipe jacking work well support structure according to claim 3 is characterized in that: A main air intake pipe is installed on the second truss, and the main air intake pipe is connected to the air intake pipes of each cylinder.

5. The pipe jacking work well support structure according to claim 3 is characterized in that: A positioning plate is fixedly installed on the outer periphery of the second truss, a movable plate is slidably installed on the positioning plate, and the cylinder is installed on the movable plate.

6. The pipe jacking work well support structure according to claim 3, characterized in that: The stopper includes a first wedge block and a second wedge block which are 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.

7. The pipe jacking work well support structure 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.

8. The pipe jacking work well support structure according to claim 7, 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 seat, and the motor is a brake motor.

9. The pipe jacking work shaft support structure according to claim 1, characterized in that: The middle parts of the crown beam and the inner support are hollowed out to form an operation space.

10. A construction method using the pipe jacking work pit support structure according to any one of claims 1 to 9, characterized in that include: (1) Prestressed pipe piles are constructed before the construction of the pipe jacking working pit. After all prestressed pipe piles are constructed and support piles are formed, a certain depth is excavated on both 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 earth inside the support pile to a certain depth and then install the first inner support. After installing the first inner support, continue to excavate the earth downward immediately. When the excavation reaches the position of the second inner support, install the second inner support. Repeat this process until all the inner supports are installed. The inner supports are installed in an integral hoisting manner. (3) A crawling device is provided between the inner support and the supporting piles formed by the prestressed pipe piles.

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