A super-long double casing structure for testing pile detection and a construction method thereof

Abstract

The application discloses a super-long double casing structure for test pile detection and a construction method thereof, and relates to the field of test pile detection.The super-long double casing structure for test pile detection comprises a section one and a section two, and the section one and the section two are connected by splicing; the difficulty of transportation and on-site assembly is reduced through maximum curing design of the product; the construction difficulty is reduced through the design of the connecting section of the double casing structure, the installation precision of the double casing is higher, and the adhesion of the inner casing and the outer casing caused by the different centers of the inner casing and the outer casing in the on-site splicing process of the double casing is avoided, so that the inaccurate experimental data caused by the adhesion is avoided.The construction method of the super-long double casing structure for test pile detection is simple in construction and high in installation precision.

Description

Technical Field

[0001] This invention relates to the technical field of test pile testing, specifically to a double-casing structure for test pile testing and its construction method. Background Technology

[0002] The most widely used foundation type in the construction industry is the pile foundation. With the increasing scarcity of urban land and the rapid development and utilization of underground space, the depth of foundation pits is also increasing in order to increase the underground building area. In order to shorten the construction period and meet the requirements of pile foundation construction, it is generally necessary to complete the test pile test and pile foundation construction as early as possible. Test pile construction is often carried out several meters above the bottom elevation of the foundation pit. In order to obtain accurate experimental data, the frictional resistance of the part above the top elevation of the pile needs to be completely eliminated, thereby providing data support for the later design.

[0003] Early on, no measures were taken to conduct test pile construction. After the static load test of the pile foundation, the design institute would estimate the actual bearing capacity by multiplying it by the corresponding reduction factor based on experience. This method mainly relies on experience for calculation and lacks theoretical basis. It often leads to waste of bearing capacity or insufficient bearing capacity of the pile foundation in the later stage, resulting in major quality accidents.

[0004] Chinese patent CN106948390A mentions the use of a double-casing structure to eliminate frictional resistance. This method has been widely used in engineering practice, but it does not involve the splicing and installation of ultra-long double-casing structures. When the empty pile is large, it needs to be manufactured and assembled in sections to meet the needs of transportation and hoisting.

[0005] The process involves sectional fabrication and transportation to the construction site. After being vertically lifted, the inner and outer casings are assembled and welded together. However, alignment difficulties often arise during the welding process, leading to jamming between the inner and outer casings and preventing the desired effect from being achieved. Furthermore, on-site assembly and welding prolongs the construction time and may induce other quality accidents such as hole collapse and hole shrinkage. Summary of the Invention

[0006] The purpose of this invention is to provide an ultra-long double-casing structure for test pile detection and its construction method, so as to overcome the technical problems of existing ultra-long double-casing structures, which are difficult to align during the segmented manufacturing and welding process, resulting in jamming between the inner and outer casings, failing to achieve the expected effect, and having a long construction time.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] An ultra-long double-casing structure for testing piles includes a first section and a second section, which are spliced ​​together.

[0009] The first section includes a lower inner sheath, a lower outer sheath, a connecting sheath, a first temporary fixing device, a belt, an annular gasket, a lower lifting lug, and a reinforcing plate. The lower outer sheath is fitted over the lower inner sheath. One end of the temporary fixing device is fixedly connected to the lower outer sheath, and the other end is fixedly connected to the inner sheath. The connecting sheath is fitted over the lower outer sheath. The lower outer sheath is placed on the annular gasket, which is set on the belt. The belt is fixedly connected to the lower inner sheath. The lower lifting lug is fixedly connected to one side of the sheath. The reinforcing plate is fixedly connected to the bottom of the belt.

[0010] Section 2 includes a port sealing plate, a second temporary fixing device, an upper inner casing, an upper outer casing, a supporting rib, and an upper lifting lug. The upper inner casing is located inside the upper outer casing. The upper ends of the upper inner casing and the upper outer casing are fixed and sealed with a sealing plate, and the lower ends are fixed with the second temporary fixing device. The supporting rib is located between the upper inner casing and the upper outer casing, and the upper lifting lug is located on the outside of the upper outer casing.

[0011] Preferably, both the first temporary fixing device and the second temporary fixing device are temporary fixing steel bars.

[0012] Preferably, the annular gasket is an annular rubber gasket.

[0013] Preferably, the belt is a steel belt.

[0014] Preferably, the belt is "L" shaped, with an annular gasket on the straight section of the belt.

[0015] Preferably, the annular gasket is about 20mm thick, and its outward-curved portion constrains the lower section of the outer casing to keep it centered.

[0016] Preferably, one end of the first temporary fixing device is welded to the lower outer casing, and the other end is welded to the lower inner casing.

[0017] Preferably, the port sealing plate is made of steel plate, and the port steel plate fully welds and seals the upper end of the upper inner casing and the upper outer casing.

[0018] A construction method for an ultra-long double-casing structure used for test pile detection includes the following steps:

[0019] S1. Use the lower lifting lug to lower section one into the pile hole until the inner casing and connecting casing of the lower section are above the ground. Use a spirit level to adjust the upper opening of section one to be level and temporarily fix it with a crossbeam.

[0020] S2. After lifting section two using the upper lifting lugs, align and weld the lower opening of the inner casing of the upper section and the upper opening of the inner casing of the upper section, remove the temporary fixation of section one, and then use a crane to lift it into the air and cut off the first fixing device and the second temporary fixing device.

[0021] S3. After sliding the connecting sleeve to the designated position, weld it fully to the lower outer sleeve and the upper outer sleeve respectively to form a closed structure;

[0022] S4. After the assembly and welding are completed, use a crane to slowly lower the entire enclosed structure until the belt is at the designed pile top elevation, and the entire installation and splicing process is completed.

[0023] Compared with the prior art, the present invention has the following technical effects:

[0024] This invention discloses an ultra-long double-casing structure for testing test piles. The structure comprises section one and section two, which are spliced ​​together. By maximizing the product's curing design, the difficulty of transportation and on-site assembly is reduced. The design of the connecting sections of the double-casing structure further reduces construction difficulty, resulting in higher installation accuracy and preventing misalignment of the inner and outer casings during on-site splicing, which could lead to adhesion and inaccurate experimental data. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a structural schematic diagram of a segment of an ultra-long double-casing structure for testing piles provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the second section of an ultra-long double-casing structure for testing piles provided in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the overall structure of an ultra-long double-casing structure for testing piles provided in an embodiment of the present invention;

[0029] In the diagram: 1. Lower inner casing; 2. Lower outer casing; 3. Connecting casing; 4. Port sealing plate; 5. First temporary fixing device; 6. Upper inner casing; 7. Upper outer casing; 8. Waist belt; 9. Annular gasket; 10. Lower lifting lug; 11. Reinforcing plate; 12. Support rib; 13. Upper lifting lug; 14. Second temporary fixing device. Detailed Implementation

[0030] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] This invention improves the structure of the double casing by redesigning the connection section, reducing construction difficulty and increasing installation accuracy. It avoids misalignment between the inner and outer casings during on-site assembly, preventing adhesion and inaccurate experimental data. Furthermore, it addresses the difficulty of casing connection when using double casings to eliminate skin friction above the pit bottom. The double casing structure isolates the pile from the surrounding soil, effectively eliminating skin friction and obtaining accurate and reliable experimental data.

[0037] As attached Figure 1-3 As shown, in a preferred embodiment of the present invention, an ultra-long double-casing structure for testing piles is provided, comprising a first section and a second section, which are spliced ​​together.

[0038] The first section includes a lower inner protective sleeve 1, a lower outer protective sleeve 2, a connecting sleeve 3, a first temporary fixing device 5, a waist belt 8, an annular gasket 9, a lower lifting lug 10, and a reinforcing plate 11. The lower outer protective sleeve 2 is fitted over the lower inner protective sleeve 1, temporarily forming a double-layered protective sleeve. The top of the lower inner protective sleeve 1 is higher than the top of the lower outer protective sleeve. One end of the temporary fixing device 5 is fixedly connected to the top of the lower outer protective sleeve 2, and the other end is fixedly connected to the lower inner protective sleeve 1. The connecting sleeve 3 is fitted over the lower outer protective sleeve 2. The lower outer protective sleeve 2 is placed on the annular gasket 9, and the rubber gasket deforms under its own weight to achieve a sealing effect. The annular gasket 9 is set on the waist belt 8, which is fixedly connected to the lower inner protective sleeve 1. The lower lifting lug 10 is fixedly connected to one side of the protective sleeve 3, and the reinforcing plate 11 is fixedly connected to the bottom of the waist belt 8.

[0039] Section Two includes a port sealing plate 4, a second temporary fixing device 14, an upper inner casing 6, an upper outer casing 7, a support rib 12, and an upper lifting lug 13. The upper inner casing 6 is located inside the upper outer casing 7. The tops of the upper inner casing 6 and the upper outer casing 7 are flush. The upper ends of the upper inner casing 6 and the upper outer casing 7 are fully welded shut by the port sealing plate 4. The lower part of the upper inner casing 6 extends beyond the lower opening of the upper outer casing 7. The lower openings of the upper inner casing 6 and the upper outer casing 7 are spot-welded and fixed by the second temporary fixing device 14. The support rib 12 is located between the upper inner casing 6 and the upper outer casing 7. The support rib 12 is used to provide support for the upper inner casing 6 and the upper outer casing 7, enhancing the stability and load-bearing capacity of the inner and outer casing structures. The upper lifting lug 13 is located on the outside of the upper outer casing 7.

[0040] In one embodiment of the present invention, the waist belt 8 is welded to the lower inner sleeve 1, and the port sealing plate 4 is made of steel plate. The port steel plate fully welds and seals the upper end of the upper inner sleeve 6 and the upper outer sleeve 7.

[0041] In one embodiment of the present invention, the waist belt 8 can be a steel waist belt, the waist belt 8 is "L" shaped, the annular gasket 9 is an annular rubber gasket, the annular gasket 9 is provided on the straight section of the steel waist belt 8, the thickness of the annular gasket 9 is about 20mm, and its outward folding part constrains the lower section outer protective sleeve 2 to make it centered.

[0042] In one embodiment of the present invention, both the first temporary fixing device 5 and the second temporary fixing device are temporary fixing steel bars. The temporary fixing steel bars temporarily spot weld the lower inner casing 1 to the upper two openings of the lower outer casing, which facilitates transportation and installation. The connecting casing 3 is sleeved outside the lower outer casing 2.

[0043] This invention also provides a construction method for an ultra-long double-casing structure for test pile detection, comprising the following steps:

[0044] Section 1 is lowered into the pile hole using the lower lifting lug 10 until the inner casing 1 and connecting casing 3 of the lower section are above the ground. The upper opening of section 1 is adjusted to be level using a spirit level and temporarily fixed by a crossbeam.

[0045] After lifting section two using the upper lifting lug 13, align and fully weld the lower opening of the upper inner casing 6 and the upper opening of the lower inner casing 1, remove the temporary fixation of section one, then lift it into the air with a crane, cut off all temporary fixing devices 5, slide the connecting casing 3 to the designated position, and then fully weld it to the lower outer casing 2 and the upper outer casing 1 respectively to form a closed structure.

[0046] After the assembly and welding are completed, the entire enclosed structure is slowly lowered using a crane until the steel belt 8 is at the designed pile top elevation, and the entire installation and splicing process is completed.

[0047] After the pile concrete is poured and before the pile foundation testing is conducted once the design strength is reached, the end sealing plate 4 is cut off, separating the inner and outer cylinders to allow for relative sliding. During the test loading, the soil above the pile top elevation does not contact the inner casing, thus obtaining accurate and valid experimental data.

[0048] This invention reduces the difficulty of transportation and on-site assembly by maximizing the solidification of the product design. The design of the connection section of the double-casing structure reduces the construction difficulty and makes the installation accuracy of the double-casing higher. It avoids the situation where the inner and outer casings are not concentric during the on-site splicing of the double casings, which leads to the adhesion of the inner and outer casings and thus inaccurate experimental data.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0050] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A construction method for an ultra-long double-casing structure used for test pile detection, characterized in that, The structure adopts an ultra-long double-tube structure, which includes a first section and a second section, and the first section and the second section are spliced ​​together. The first section includes a lower inner sleeve (1), a lower outer sleeve (2), a connecting sleeve (3), a first temporary fixing device (5), a belt (8), an annular gasket (9), a lower lifting lug (10), and a reinforcing plate (11). The lower outer sleeve (2) is fitted over the lower inner sleeve (1), and the top of the lower inner sleeve (1) is higher than the top of the lower outer sleeve (2). One end of the first temporary fixing device (5) is fixedly connected to the lower outer sleeve (2), and the other end is fixedly connected to the inner sleeve (1). The connecting sleeve (3) is slidably fitted over the lower outer sleeve (2) and is used to connect the upper inner sleeve (6) and the lower inner sleeve (1). After welding, the upper slide is connected to the upper outer casing (7), the lower outer casing (2) is placed on the annular gasket (9), the annular gasket (9) is set on the waist belt (8), the annular gasket (9) is an annular rubber gasket, the waist belt (8) is fixedly connected to the lower inner casing (1), the waist belt (8) is "L" shaped, the annular gasket (9) is set on the straight section of the waist belt (8), the annular gasket (9) is 20mm thick, its outward part constrains the lower outer casing (2) to make it centered, the lower lifting lug (10) is fixedly connected to one side of the casing (3), and the reinforcing plate (11) is fixedly connected to the bottom of the waist belt (8); Section 2 includes a port sealing plate (4), a second temporary fixing device (14), an upper inner casing (6), an upper outer casing (7), a support rib (12), and an upper lifting lug (13). The upper inner casing (6) is located inside the upper outer casing (7). The lower part of the upper inner casing (6) extends to the lower opening of the upper outer casing (7). The upper ends of the upper inner casing (6) and the upper outer casing (7) are fixed and sealed with the sealing plate (4), and the lower opening is fixed with the second temporary fixing device (14). The support rib (12) is located between the upper inner casing (6) and the upper outer casing (7). The upper lifting lug (13) is located on the outside of the upper outer casing (7). The port sealing plate (4) is made of steel plate. The port sealing plate (4) fully welds and seals the upper ends of the upper inner casing (6) and the upper outer casing (7). The construction method includes the following steps: S1. The first section is lowered into the pile hole by means of the lower lifting lug (10) until the inner casing (1) of the lower section and the connecting casing (3) are above the ground. The upper opening of the first section is adjusted to be horizontal by using a spirit level and temporarily fixed by a crossbeam. S2. After lifting the second section using the upper lifting lug (13), align and weld the lower opening of the upper inner tube (6) and the upper opening of the lower inner tube (1) to remove the temporary fixation of the first section. Then, use a crane to lift it into the air and cut off the first temporary fixing device (5) and the second temporary fixing device (14). S3. After sliding the connecting sleeve (3) to the designated position, weld it fully to the lower outer sleeve (2) and the upper outer sleeve (7) respectively to form a closed structure. S4. After the assembly and welding are completed, the entire enclosed structure is slowly lowered using a crane until the belt (8) is located at the designed pile top elevation, and the installation and splicing are completed. S5. After the concrete of the pile body is poured, before the pile foundation test is carried out when the design strength is reached, the port sealing plate (4) is cut off so that the inner and outer cylinders can be separated and can slide relative to each other.

2. The construction method of an ultra-long double-casing structure for test pile detection according to claim 1, characterized in that, Both the first temporary fixing device (5) and the second temporary fixing device (14) are temporary fixing steel bars.

3. The construction method of an ultra-long double-casing structure for test pile detection according to claim 1, characterized in that, The belt (8) is a steel belt.

4. The construction method of an ultra-long double-casing structure for test pile detection according to claim 1, characterized in that, One end of the first temporary fixing device (5) is welded to the lower outer casing (2), and the other end is welded to the lower inner casing (1).

Images