Construction methods for extracting PC (polycarbonate) piles

Abstract

This application discloses a construction method for extracting PC (Precast Concrete) piles, comprising the following steps: S1, before pile extraction, dividing three adjacent steel pipe piles into a construction unit from the outside to the inside at the outermost end of the support structure; S2, at the start of pile extraction, installing steel plate baffles and extracting the Larssen steel sheet piles on both sides of the middle steel pipe pile; S3, moving a hydraulic bulldozer above the outer steel pipe pile and fixing it to the steel plate baffle; S4, extracting the outer steel pipe pile while simultaneously compacting the soil inside the pile using the hydraulic bulldozer; after the steel pipe pile is extracted 10cm, removing the hydraulic bulldozer and extracting all the steel pipe piles; S5, repeating steps S3-S4 for the middle steel pipe pile until it is extracted; S6, removing the steel plate baffles and reserving the inner steel pipe pile; S7, repeating steps S1-S6 until all piles of the support structure are extracted. This method can effectively resist the soil adhering to the pile during pile extraction, improving the stability of the surrounding soil during PC pile extraction.

Description

Technical Field

[0001] This application relates to the field of foundation pit support engineering technology, and in particular to a construction method for extracting PC method piles. Background Technology

[0002] Precast concrete (PC) piles are composite piles formed by combining Larssen piles with steel pipes to create various cross-sections. They are connected to Larssen sheet piles via interlocking connections welded to the steel pipe piles. The steel pipe piles retain soil, while the sheet piles retain water. PC piles are commonly used in deep foundation pit support. Compared to traditional cast-in-place piles of the same stiffness, they can save approximately 6% to 16% in cost, and this cost does not even consider the treatment costs of the cast-in-place pile slurry, making them relatively more economical. Furthermore, in terms of retaining pile construction, PC piles have a shorter construction period than cast-in-place piles, and the entire process is pollution-free, with simple inspection and acceptance procedures, and they can be reused. Therefore, PC piles are highly valued and favored in the foundation pit industry.

[0003] After the deep foundation pit construction is completed and backfilled, the support structure needs to be dismantled. For the extraction of PC method piles, the traditional method is to first extract the Larssen sheet piles on both sides of the steel pipe pile, and then extract the steel pipe pile itself. However, because the soil around the PC method pile has been in contact with the pile body for too long, it will generate adhesion to the pile body. This can lead to excessive soil carrying around the pile during extraction, causing ground settlement and displacement, and other quality problems, seriously affecting the subsequent construction cycle.

[0004] Therefore, in order to improve the stability of the soil around the pile during the extraction of PC piles, it is necessary to improve the existing pile extraction methods. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application provides a construction method for extracting PC method piles. By installing steel plate baffles and hydraulic bulldozing devices around the pile body, the method solves the quality problems such as excessive soil carried by the pile body during the extraction of PC method piles, which cause ground settlement and displacement.

[0006] This application provides a construction method for extracting PC method piles, with the following technical solution:

[0007] A construction method for extracting PC method piles includes the following steps:

[0008] S1. Before the pile extraction construction, the adjacent steel pipe piles I1, II and III are divided into a construction unit from the outside to the inside at the outermost end of the PC method pile support structure along the length direction.

[0009] S2. When the pile extraction construction begins, steel plate baffles are installed around the steel pipe piles and Larssen sheet piles in the construction unit, and the Larssen sheet piles on both sides of steel pipe pile II are extracted respectively.

[0010] S3. Move the hydraulic bulldozing device above the steel pipe pile I and fix it on the steel plate baffle;

[0011] S4. Use a pile extractor to extract steel pipe pile I, and at the same time use a hydraulic bulldozer to squeeze the soil inside the pile; when steel pipe pile I is pulled out 10cm, remove the hydraulic bulldozer and pull out all of steel pipe pile I.

[0012] S5. Repeat steps S3-S4 for steel pipe pile II until it is pulled out.

[0013] S6. After steel pipe pile I and steel pipe pile II in the construction unit are pulled out, remove the steel plate baffle and reserve steel pipe pile III as the benchmark for subsequent construction units.

[0014] S7. Repeat steps S1-S6 until all piles of the support structure are pulled out.

[0015] Furthermore, the steel plate baffle is installed at the connection between the PC method pile and the ground within the construction unit to resist the soil around the PC method pile and reduce the adhesion of soil to the outside of the pile during the pile extraction process.

[0016] Furthermore, the steel plate baffle is composed of an upper baffle plate and a lower baffle plate spliced ​​together. The upper baffle plate and the lower baffle plate are provided with connecting parts for splicing and assembly on the side facing the PC method pile. The connecting parts are respectively located at both ends of the length direction of the baffle plate facing the PC method pile.

[0017] Furthermore, a conformal section that conforms to the horizontal cross-section of the PC method pile is provided between the connecting parts of the upper and lower baffle plates.

[0018] Furthermore, there is a 10cm gap between the conformal sections of the upper and lower baffle plates and the steel pipe piles I and II; there is also a 10cm gap between the conformal sections of the upper and lower baffle plates and the Larssen sheet piles on both sides of the steel pipe pile II.

[0019] Furthermore, the connecting parts are a straight connecting part and a conformal connecting part. The straight connecting part is located on the side of steel pipe pile I away from steel pipe pile II, and the conformal connecting part is located on the side of steel pipe pile III away from steel pipe pile II.

[0020] Furthermore, the conformal connection portion is conformally arranged with the Larssen sheet pile on the side of the steel pipe pile III away from the steel pipe pile II.

[0021] Furthermore, the steel plate baffle is provided with anchor points, which are used for the installation and fixation of the hydraulic bulldozing device.

[0022] Furthermore, the hydraulic bulldozing device includes a support assembly and a squeezing assembly for squeezing the soil inside the pile during the extraction of the steel pipe pile. The support assembly is connected to the steel plate baffle through anchor points.

[0023] In summary, this application has at least one of the following beneficial effects: The construction method for extracting PC method piles provided in this application is applicable to the extraction construction of PC method pile support structures. By installing steel plate baffles and hydraulic bulldozing devices around the pile body, the soil attached to the steel plate piles can be effectively resisted during the extraction process, thereby reducing the phenomenon of soil being carried out during the extraction process and improving the stability of the surrounding soil when extracting PC method piles. At the same time, this construction method is simple to operate, the required steel plate baffles and hydraulic bulldozing devices have low manufacturing costs, can be reused, are green and environmentally friendly, and have no pollution or waste, thus having a certain degree of economic efficiency. Attached Figure Description

[0024] Figure 1 This is a structural schematic diagram of an embodiment of this application;

[0025] Figure 2 This is a top view of an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the steel plate baffle structure in the embodiments of this application;

[0027] Figure 4 This is a schematic diagram illustrating the operation of an embodiment of this application;

[0028] Explanation of reference numerals in the attached drawings: 1-Steel pipe pile I; 2-Steel pipe pile II; 3-Steel pipe pile III; 4-Larsen sheet pile; 5-Steel sheet baffle; 6-Hydraulic bulldozing device; 7-Soil; 8-Anchor point; 9-Construction unit with completed pile extraction; 10-Construction unit currently undergoing pile extraction; 51-Upper baffle; 52-Lower baffle; 61-Support assembly; 62-Extrusion assembly; 511-Straight connection of upper baffle; 512-Conformal connection of upper baffle; 521-Straight connection of lower baffle; 522-Conformal connection of lower baffle. Detailed Implementation

[0029] The present application will be further described in detail below with reference to the accompanying drawings.

[0030] A construction method for extracting PC method piles includes the following steps:

[0031] S1. Before the pile extraction construction, the adjacent steel pipe piles I1, II2 and III3 are divided into a construction unit from the outside to the inside at the outermost end of the PC method pile support structure along the length direction.

[0032] S2. When the pile extraction construction begins, steel plate baffles 5 are installed around the steel pipe piles and Larssen sheet piles in the construction unit, and Larssen sheet piles 4 between steel pipe pile II2 and steel pipe pile I1 and steel pipe pile III3 are extracted respectively.

[0033] S3. Move the hydraulic bulldozing device 6 above the steel pipe pile I1 and fix it on the steel plate baffle 5;

[0034] S4. Use a pile extractor to extract the steel pipe pile I1, and at the same time use a hydraulic bulldozer 6 to squeeze the soil inside the pile; when the steel pipe pile I1 is pulled out 10cm, remove the hydraulic bulldozer 6 and pull out the steel pipe pile I1 completely.

[0035] S5. Repeat steps S3-S4 for steel pipe pile II2 until all of them are pulled out.

[0036] S6. After steel pipe piles I1 and II2 in the construction unit are pulled out, remove the steel plate baffle 5 and reserve steel pipe pile III3 as the benchmark for subsequent construction units.

[0037] S7. Repeat steps S1-S6 until all piles of the PC method pile support structure are pulled out.

[0038] In this embodiment, starting from the outermost end of the support structure, the three adjacent steel pipe piles and the two Larssen sheet piles used to connect the three steel pipe piles in the PC method pile support structure are first divided into a construction unit. Then, steel plate baffles 5 are installed around the steel pipe piles and Larssen sheet piles 4 in the construction unit to improve the stability of the soil around the piles during pile extraction. A hydraulic bulldozer device 6 is installed above the steel pipe piles to squeeze the soil inside the piles during the extraction process. After all the steel pipe piles I1, II2, and Larssen sheet piles 4 in the construction unit are extracted, the steel plate baffles 5 and the hydraulic bulldozer device 6 are installed in the subsequent divided construction units. The Larssen sheet piles are extracted first, and then the steel pipe piles are extracted. The reason for this phased extraction is that it reduces the impact on the overall quality of the soil 7 during pile extraction and decreases the difficulty of extraction. Furthermore, Larssen sheet piles are generally shorter than steel pipe piles, and their plate-like shape makes them easier to extract first. Subsequent extraction of steel pipe piles requires the use of a hydraulic bulldozer 6 for compression; phased extraction reduces repetitive work. The hydraulic bulldozer 6 is mainly used to block the soil inside the steel pipe pile from being moved during extraction, similar to the principle of an injection syringe. As the steel pipe pile moves upward with the extraction machine, the hydraulic bulldozer 6 blocks and compresses the soil inside the pile, making the soil more compact and preventing it from being moved by the pile during subsequent extraction. Figure 4 As shown, after all the steel pipe piles I1, II2 and Larssen sheet piles 4 in construction unit 9, which has completed the pile extraction construction, are pulled out, steel pipe pile III3 is left as the reference, and steel pipe pile III3 in construction unit 9, which has completed the pile extraction construction, is used as steel pipe pile I1 in construction unit 10, which is currently carrying out pile extraction construction.

[0039] In this embodiment, combined with Figure 1 As shown, the steel plate baffle 5 is installed at the connection between the PC method pile and the ground within the construction unit. It is used to block the soil around the PC method pile and reduce the adhesion of soil to the outside of the pile during the pile extraction process. Generally, after the foundation pit is backfilled, a portion of the top of the PC method pile is reserved for subsequent construction. The steel plate baffle 5 is installed and fixed using the reserved portion of the PC method pile. At the same time, the steel plate baffle 5 is mainly used to block soil. The steel plate baffle 5 should preferably be made of steel plate with a certain thickness. The specific thickness can be selected according to the required rigidity during use. In this embodiment, the steel plate baffle 5 is made of ordinary steel plate with a thickness of 1cm.

[0040] In this embodiment, the steel plate baffle 5 is assembled from an upper baffle 51 and a lower baffle 52. The upper baffle 51 and the lower baffle 52 are provided with connecting parts for splicing on the side facing the PC pile. The connecting parts are respectively provided at both ends of the length direction of the baffle facing the PC pile. A conforming section that follows the horizontal cross section of the PC pile is provided between the connecting parts of the upper baffle 51 and the lower baffle 52.

[0041] Combination Figure 2 and Figure 3 As shown, the steel plate baffle 5 is composed of two pieces, an upper baffle 51 and a lower baffle 52, which are spliced ​​together and fixed at the connection points at both ends along the length direction by bolt assemblies. Making the steel plate baffle 5 into a modular form rather than a single piece makes the installation and disassembly of the steel plate baffle 5 simpler, and also makes it easier to transport and store when not in use, taking up less space. The connection point between the upper baffle 51 and the lower baffle 52 facing the PC pile is made into a conformal section that follows the horizontal cross-section of the PC pile. The purpose is not only to stabilize the soil around the pile, but also to block the soil moved by the outside of the pile, reducing the occurrence of quality problems on the ground.

[0042] In this embodiment, combined with Figure 2 As shown, there is a 10cm gap between the conformal sections of the upper baffle 51 and the lower baffle 52 and the steel pipe piles I1 and II2; there is also a 10cm gap between the conformal sections of the upper baffle 51 and the lower baffle 52 and the Larssen sheet piles 4 on both sides of the steel pipe pile II2; the gap between the steel pipe piles I1 and II2 and the steel plate baffle 5 is mainly to take into account that the installation position of each steel pipe pile in the construction unit may deviate from the position on the drawing during installation. Therefore, it is necessary to reserve a gap on the steel plate baffle 5 for the position of the pulled-out steel pipe pile. It is more appropriate to leave a 10cm gap when processing the steel plate baffle 5; the gap between the conformal sections of the upper baffle 51 and the lower baffle 52 and the Larssen sheet piles 4 on both sides of the steel pipe pile II2 is for the same reason as the gap set for the steel pipe piles mentioned above, and will not be repeated here.

[0043] In this embodiment, combined with Figure 2 and Figure 3 As shown, the connecting parts of the upper baffle 51 and the lower baffle 52 are a straight connecting part and a conformal connecting part, respectively. The connecting parts of the upper baffle 51 are the upper baffle straight connecting part 511 and the upper baffle conformal connecting part 512, and the connecting parts of the lower baffle 52 are the lower baffle straight connecting part 521 and the lower baffle conformal connecting part 522. The upper baffle straight connecting part 511 and the lower baffle straight connecting part 521 are located on the side of the steel pipe pile I1 away from the steel pipe pile II2, and the upper baffle conformal connecting part 512 and the lower baffle conformal connecting part 522 are located on the side of the steel pipe pile III3 away from the steel pipe pile II2. The upper baffle conformal connecting part 512 and the lower baffle conformal connecting part 522 are conformally connected to the Larssen sheet pile 4 on the side of the steel pipe pile III3 away from the steel pipe pile II2.

[0044] In this embodiment, the steel plate baffle 5 is provided with anchor points 8, which are used for the installation and fixing of the hydraulic bulldozing device 6. The hydraulic bulldozing device 6 includes a support assembly 61 and a squeezing assembly 62 for squeezing the soil inside the pile when the steel pipe pile is extracted. The support assembly 61 is connected to the steel plate baffle 5 through the anchor points 8.

[0045] Combination Figure 1 As shown, the support component 61 in the hydraulic bulldozing device 6 is a support assembled from several ordinary steel pipes. In this embodiment, three steel pipes are combined to form a triangular support, which can leave space for the pile extractor to perform preliminary pile extraction on the steel pipe pile while ensuring the stability of the support. At the same time, anchor points 8 for fixing the triangular support are provided on the steel plate baffle 5, which makes the assembly and disassembly of the triangular support simpler and easier for workers to operate. The extrusion component 62 is formed by combining a hydraulic jack and a disc. The size of the disc is 5cm smaller than the internal size of the steel pipe pile, leaving a 5cm gap. This is to avoid affecting the operation of the pile extractor when the verticality of the steel pipe pile is poor; the hydraulic jack provides a directional squeezing force to the soil inside the pile when the steel pipe pile is pulled out, causing the soil inside the pile to fall off the inner wall of the pile, and at the same time making the soil below the disc more compact; the hydraulic bulldozing device 6 can be removed when the steel pipe pile is pulled out 10cm. It mainly uses a principle similar to an injection needle. When the steel pipe pile moves upward with the pile extractor, the squeezing component 62 blocks and squeezes the soil inside the pile, making the soil inside the pile more compact. In the subsequent pile extraction process, the soil inside the pile is not easily moved by the pile body.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A construction method for extracting PC method piles, characterized in that: Includes the following steps: S1. Before the pile extraction construction, the outermost end of the PC method pile support structure is divided into steel pipe pile I, steel pipe pile II and steel pipe pile III as a construction unit from the outside to the inside. S2. When the pile extraction construction begins, install steel plate baffles at the construction unit and extract the Larssen steel sheet piles on both sides of steel pipe pile II respectively. S3. Move the hydraulic bulldozing device above the steel pipe pile I and fix it on the steel plate baffle; S4. Use a pile extractor to extract steel pipe pile I, and at the same time use a hydraulic bulldozer to squeeze the soil inside the pile; when steel pipe pile I is pulled out 10cm, remove the hydraulic bulldozer and pull out all of steel pipe pile I. S5. Repeat steps S3-S4 for steel pipe pile II until it is pulled out. S6. After steel pipe pile I and steel pipe pile II in the construction unit are pulled out, remove the steel plate baffle and reserve steel pipe pile III as the benchmark for subsequent construction units. S7. Repeat steps S1-S6 until all piles of the support structure are pulled out. The steel plate baffle is installed at the connection between the PC method pile and the ground within the construction unit to resist the soil around the PC method pile and reduce the adhesion of soil to the outside of the pile during the pile extraction process. The steel plate baffle is composed of an upper baffle plate and a lower baffle plate spliced ​​together. The upper baffle plate and the lower baffle plate are provided with connecting parts for splicing and assembly on the side facing the PC method pile. The connecting parts are respectively provided at both ends of the length direction of the baffle plate facing the PC method pile. A conformal section that conforms to the horizontal cross-section of the PC method pile is provided between the connecting parts of the upper and lower baffle plates. The upper and lower sections of the baffle plate have a 10cm gap with steel pipe pile I and steel pipe pile II; the upper and lower sections of the baffle plate have a 10cm gap with the Larssen sheet piles on both sides of steel pipe pile II.

2. The construction method for extracting PC method piles according to claim 1, characterized in that: The connecting parts are a straight connecting part and a conformal connecting part. The straight connecting part is located on the side of steel pipe pile I away from steel pipe pile II, and the conformal connecting part is located on the side of steel pipe pile III away from steel pipe pile II.

3. The construction method for extracting PC method piles according to claim 2, characterized in that: The conformal connection is conformally arranged with the Larssen sheet pile on the side of steel pipe pile III away from steel pipe pile II.

4. The construction method for extracting PC method piles according to claim 1, characterized in that: Anchor points are provided on the steel plate baffle, which are used for the installation and fixation of the hydraulic bulldozing device.

5. The construction method for extracting PC method piles according to claim 4, characterized in that: The hydraulic bulldozing device includes a support assembly and a squeezing assembly for squeezing the soil inside the pile during the extraction of the steel pipe pile. The support assembly is connected to the steel plate baffle through anchor points.

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