Pipeline casing structure for preventing collapse during pile foundation construction in karst formations

Abstract

This application discloses a casing structure for anti-collapse holes in pile foundation construction in karst formations, including an outer sleeve and an inner sleeve. The inner sleeve is disposed inside the outer sleeve. The outer sleeve includes multiple first sleeve sections connected end-to-end, and the inner sleeve includes multiple second sleeve sections connected end-to-end. It also includes: an installation component, with the installation component mounted on the top of each second sleeve section; lifting lugs welded to the installation component; a first vertical reinforcing rib, with the first vertical reinforcing rib having a sliding groove adapted to the installation component. The outer sleeve and inner sleeve are driven into the hole, forming an anti-collapse casing structure that effectively prevents pile hole collapse. During the hoisting of the second sleeve sections, a main hook is used to connect the second sleeve section to the main lifting cable, allowing the second sleeve section to be vertically hoisted to the guiding and positioning device, which improves the efficiency of driving and connecting the inner sleeve.

Description

Technical Field

[0001] This application relates to the field of pile foundation casing technology, and in particular to a pile foundation anti-collapse casing structure for karst formations. Background Technology

[0002] The GZSG-3 section of the new Zhuhai-Zhaoqing High-Speed ​​Railway Gaoming-Zhaoqing East section's pre-station engineering project spans from DK25+565 to DK41+207.817, with a total length of 15.643km. The Xijiang Grand Bridge, located between Yong'an Town and Shapu Town in Zhaoqing City, Guangdong Province, crosses the main channel of the Xijiang River approximately 3.5km downstream of the existing Xijiang Grand Bridge on the Jiangzhao Expressway. It is a three-tower cable-stayed bridge with a span of (70+148+435+435+148+70) meters, currently the world's largest steel box girder composite railway cable-stayed bridge, and a key and challenging project along the entire line.

[0003] According to geological exploration data, the piers of the Xijiang Grand Bridge are overlain by Quaternary Holocene alluvial-diluvial deposits (Q4al+pl) and underlain by Lower Carboniferous rock terraces (C1y). The rock and soil layers are classified from top to bottom as: silt (0), fine sand {(2)4-2}, and limestone {(11)4-2, (11)4-3}. Among them, limestone karst phenomena are well developed, mainly in the form of caves. For the piers in karst strata, it is necessary to pre-grout the caves and lower double-layer steel casings throughout the construction process to avoid the occurrence of hole collapse accidents.

[0004] In existing technology, both the inner and outer casings are horizontally hoisted to the borehole position using wire ropes, employing a two-point lifting method with two wire ropes as the main lifting tools. Horizontal hoisting is carried out using wire ropes and shackles. However, during the insertion or connection process of the horizontally hoisted inner casing, it is necessary to rotate it to a vertical position in mid-air. This significantly increases the workload required for inserting or connecting the inner casing, especially for inner casings with deeper insertion depths.

[0005] Therefore, it is necessary to propose a casing structure for anti-collapse holes in pile foundation construction in karst formations, which facilitates the insertion or connection of the inner casing. This has become an important technical problem that urgently needs to be solved. Utility Model Content

[0006] This application provides a casing structure for anti-collapse holes in pile foundation construction in karst formations, aiming to solve the problem that in the prior art, when horizontally hoisted inner casings are inserted or connected, it is necessary to rotate the inner casing to a vertical position in the air, which greatly increases the workload required for inserting or connecting inner casings, especially for inner casings with a deep insertion depth.

[0007] To achieve the above objectives, this application proposes a casing structure for anti-collapse holes in pile foundation construction in karst formations, comprising an outer sleeve and an inner sleeve, the inner sleeve being disposed inside the outer sleeve. The outer sleeve comprises multiple first sleeve sections connected end-to-end, and the inner sleeve comprises multiple second sleeve sections connected end-to-end. The structure also includes: an installation component, with the installation component disposed on the top of each second sleeve section; lifting lugs, welded to the installation component; a first vertical reinforcing rib, with the first vertical reinforcing rib having a first vertical reinforcing rib, the sliding groove being adapted to the installation component.

[0008] In some embodiments, the device further includes: a first transverse reinforcing rib, wherein the first transverse reinforcing rib is disposed on the inner side of the first sleeve section, and the first transverse reinforcing rib is connected to the first vertical reinforcing rib.

[0009] In some embodiments, the device further includes a second vertical reinforcing rib, which is circumferentially spaced on the inner side of the second sleeve section.

[0010] In some embodiments, it also includes: The second transverse reinforcing rib is provided on the inner side of the second sleeve section, and the second transverse reinforcing rib is connected to the second vertical reinforcing rib.

[0011] In some embodiments, it further includes: a first tapered portion, wherein the bottom of the bottommost first sleeve section is provided with a first tapered portion; and a second tapered portion, wherein the bottom of the bottommost second sleeve section is provided with a second tapered portion.

[0012] In some embodiments, two adjacent first sleeve sections are connected by welding, and two adjacent second sleeve sections are connected by welding.

[0013] This application proposes a casing structure for anti-collapse holes in pile foundation construction in karst formations. The structure includes an outer sleeve and an inner sleeve, with the inner sleeve located inside the outer sleeve. The outer sleeve comprises multiple first sleeve sections connected end-to-end, and the inner sleeve comprises multiple second sleeve sections connected end-to-end. It also includes: an installation component, with the installation component mounted on the top of each second sleeve section; lifting lugs welded to the installation component; a first vertical reinforcing rib, with the first vertical reinforcing rib having a groove adapted to the installation component. The outer sleeve and inner sleeve are driven into the hole, forming the anti-collapse casing structure and effectively preventing pile hole collapse. During the hoisting of the second sleeve sections, a main hook connects the second sleeve section to the main lifting cable, allowing the second sleeve section to be vertically hoisted to the guiding and positioning device before being slowly lowered to the riverbed, thus improving the efficiency of driving and connecting the inner sleeve. The first vertical reinforcing rib enhances the structural strength of the outer sleeve, preventing deformation. Secondly, the width of the groove in the first vertical reinforcing rib is adapted to the width of the mounting component section, improving stability during the lowering of the second sleeve section through the cooperation of the mounting component and the groove. Furthermore, the cooperation between the mounting component and the corresponding groove ensures the coaxiality of the outer and inner sleeves. Attached Figure Description

[0014] 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, wherein: Figure 1 This is a three-dimensional structural diagram of a pile foundation anti-collapse hole casing structure used in karst formation construction according to one embodiment of this application; Figure 2 for Figure 1 Enlarged view of part A in the middle; Figure 3 This is a cross-sectional view of a pile foundation anti-collapse casing structure used in karst formation construction according to an embodiment of this application; Figure 4 for Figure 3 Enlarged view of part B in the middle; Figure 5 This is a three-dimensional structural diagram of the first sleeve section in one embodiment of this application.

[0015] In the figure: outer sleeve 1, first sleeve section 11, first welding bevel 12, first vertical reinforcing rib 13, slide groove 14, first horizontal reinforcing rib 15, first tapering section 16, inner sleeve 2, second sleeve section 21, mounting part 23, lifting hole 24, lifting lug 25, second vertical reinforcing rib 26, second horizontal reinforcing rib 27, second tapering section 28, second welding bevel 29. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0017] See Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, this application proposes a casing structure for anti-collapse holes in pile foundation construction in karst formations, including an outer sleeve 1 and an inner sleeve 2. The inner sleeve 2 is disposed inside the outer sleeve 1. The outer sleeve 1 includes multiple first sleeve sections 11 connected end to end, and the inner sleeve 2 includes multiple second sleeve sections 21 connected end to end. It also includes: an installation component 23, which is provided on the top of the second sleeve section 21; a lifting lug 25, which is welded to the installation component 23; a first vertical reinforcing rib 13, which is provided on the inner side of the first sleeve section 11; and a sliding groove 14, which is provided on the first vertical reinforcing rib 13 and is adapted to the installation component 23.

[0018] The outer sleeve 1 and the inner sleeve 2 constitute the anti-collapse hole casing structure. The number of the first sleeve section 11 and the second sleeve section 21 can be selected according to the design elevation to match the design elevation. The anti-collapse hole casing structure is lowered using a vibratory hammer of not less than 400mm, but the total weight of the vibratory hammer must not exceed the design load of the construction platform. If penetration is difficult, a rotary drilling rig can be used to remove the core soil for lowering after the drilling platform is erected. To ensure the accurate positioning and verticality of the anti-collapse hole casing, a guide positioning device needs to be installed on the construction platform. The guide positioning device is not the inventive point of this application, and the specific structure of the guide positioning device is not limited here.

[0019] When driving the anti-collapse casing structure, a crawler crane is used to hoist a vibratory hammer for driving, vibrating the steel casing into the rock layer. During the driving process, two total stations observe the outer casing 1 from two vertical angles to ensure that the deviation of the center position and the inclination of the outer casing 1 meet the requirements, with a permissible horizontal error of 50mm and a vertical inclination of no more than 1%. If any abnormality is found, driving should be stopped immediately, the cause investigated, and effective corrective measures taken. If the outer casing 1 or inner casing 2 fails to sink during the driving process, vibration should be stopped immediately, and a rotary drilling rig should be used to create a pilot hole to reduce the side friction resistance of the casing. Then, the vibratory hammer should be used to continue driving, repeating this process until the outer casing 1 and inner casing 2 are driven to the design elevation.

[0020] The mounting component 23 is welded to the outside of the second sleeve section 21, and the lifting lug 25 is welded to the mounting component 23. The lifting lug 25 has a lifting hole 24 and is made of 18mm steel plate. Lifting is carried out using the lifting lug 25 and shackles. Before vertical lifting, the second sleeve section 21 needs to be rotated from horizontal to vertical.

[0021] In this embodiment, during hoisting, the main hook is attached to the lifting lug 25 at the top of the second sleeve section 21 via a sling shackle, and the auxiliary hook is attached to the bottom of the second sleeve section 21 via a shackle and wire rope. The second sleeve section 21 is then hoisted using a combination of main and auxiliary slings; the main sling ascends while the auxiliary sling descends. As the descent increases, when the second sleeve section 21 is in a vertical position, the auxiliary sling is released. After the pile is erected, the second sleeve section 21 is hoisted onto the guide positioning device and slowly lowered to the riverbed surface.

[0022] The first vertical reinforcing rib 13 can first enhance the structural strength of the outer sleeve 1 and prevent the outer sleeve 1 from deforming. Secondly, the width of the groove 14 of the first vertical reinforcing rib 13 is adapted to the width of the section of the mounting component 23. The cooperation between the mounting component 23 and the groove 14 can improve the stability of the second sleeve section 21 during the lowering process.

[0023] In this embodiment, two lifting lugs 25 are provided, and two mounting parts 23, two first vertical reinforcing ribs 13 and two sliding grooves 14 are also provided. During the lowering process of the second sleeve section 21, the coaxiality of the second sleeve section 21 and the first sleeve section 11 is ensured by the cooperation of the two mounting parts 23 with the corresponding sliding grooves 14, and the coaxiality of the outer sleeve 1 and the inner sleeve 2 is also ensured.

[0024] Specifically, the outer sleeve 1 and inner sleeve 2 are driven into the hole by insertion, forming an anti-collapse casing structure to effectively prevent the pile hole from collapsing. During the hoisting of the second sleeve section 21, the main hook connects the second sleeve section 21 to the main sling, allowing it to be vertically hoisted to the guide positioning device before being slowly lowered to the riverbed. This improves the efficiency of inserting and connecting the inner sleeve 2. The first vertical reinforcing rib 13 firstly enhances the structural strength of the outer sleeve 1, preventing deformation. Secondly, the width of the groove 14 of the first vertical reinforcing rib 13 is adapted to the width of a section of the mounting component 23. The cooperation between the mounting component 23 and the groove 14 improves the stability of the second sleeve section 21 during lowering. Furthermore, the cooperation between the mounting component 23 and the corresponding groove 14 ensures the coaxiality of the outer sleeve 1 and the inner sleeve 2.

[0025] In detail, before construction, the positioning and layout work is completed, and then drilling is carried out under the action of the rotary drilling rig until the top surface of the limestone is reached. The outer casing 1 is lowered to the top surface of the limestone, and the drill bit is replaced to carry out further drilling to reach the designed pile bottom elevation. The inner casing is then lowered to the bottom of the hole. The drill bit is replaced again to perform bottom cleaning and sediment removal. Finally, the steel cage and guide pipe are lowered, and the sediment condition is further re-measured. Only after ensuring that everything is correct can the concrete pouring construction be carried out. After that, the outer casing is pulled out.

[0026] The first sleeve section 11 and the second sleeve section 21 are made of Q345 steel plate.

[0027] See Figure 5 As shown, in some embodiments, it further includes: a first transverse reinforcing rib 15, which is provided on the inner side of the first sleeve section 11, and the first transverse reinforcing rib 15 is connected to the first vertical reinforcing rib 13. The first transverse reinforcing rib 15 is welded to the inner side of the first sleeve section 11, and the first transverse reinforcing rib 15 is welded to the first vertical reinforcing rib 13. The provision of the first transverse reinforcing rib 15 is beneficial to further increase the structural rigidity of the outer sleeve 1, disperse the stress on the outer sleeve 1, and prevent the outer sleeve 1 from deforming.

[0028] In this embodiment, two or more first transverse reinforcing ribs 15 are provided axially spaced on the inner side of a single first sleeve section 11 to improve the structural rigidity of the outer sleeve 1 and prevent the outer sleeve 1 from deforming under the action of external force.

[0029] See Figure 3 and Figure 4As shown, in some embodiments, it further includes a second vertical reinforcing rib 26, which is circumferentially spaced on the inner side of the second sleeve section 21. The second vertical reinforcing rib 26 is used to enhance the rigidity of the second sleeve section 21 and disperse the external force on the second sleeve section 21, thereby preventing the second sleeve section 21 from deforming.

[0030] In this embodiment, the second vertical reinforcing rib 26 includes eight ribs spaced apart circumferentially. Two rings of second vertical reinforcing ribs 26 are provided inside the second sleeve section 21. One ring of second vertical reinforcing ribs 26 is located near the top of the second sleeve section 21, and the other ring of second vertical reinforcing ribs 26 is located near the bottom of the second sleeve section 21. The two rings of second vertical reinforcing ribs 26 effectively enhance the structural rigidity of the top and bottom of the inner sleeve 2, and effectively prevent the second sleeve section 21 from deforming during the insertion process.

[0031] See Figure 3 and Figure 4 As shown, in some embodiments, it further includes: a second transverse reinforcing rib 27, which is provided on the inner side of the second sleeve section 21, and the second transverse reinforcing rib 27 is connected to the second vertical reinforcing rib 26. The second transverse reinforcing rib 27 is welded to the inner side of the second sleeve section 21, and the second transverse reinforcing rib 27 is connected to the second vertical reinforcing rib 26 by welding. The provision of the second transverse reinforcing rib 27 is beneficial to enhancing the structural rigidity of the inner sleeve 2 and effectively preventing deformation of the second sleeve section 21.

[0032] See Figure 1 and Figure 3 As shown, in some embodiments, it further includes: a first tapered portion 16, which is provided at the bottom of the bottommost first sleeve section 11. Along the axial downward direction, the inner diameter of the first tapered portion 16 remains constant while the outer diameter gradually decreases. The first tapered portion 16 is integrally formed with the first sleeve section 11. A second tapered portion 28 is provided at the bottom of the bottommost second sleeve section 21. Along the axial downward direction, the inner diameter of the second tapered portion 28 remains constant while the outer diameter gradually decreases. The second tapered portion 28 is integrally formed with the second sleeve section 21. The provision of the first tapered portion 16 and the second tapered portion 28 can effectively reduce the difficulty of driving the first sleeve section 11 and the second sleeve section 21, and increase the speed at which the first sleeve section 11 and the second sleeve section 21 penetrate the riverbed.

[0033] See Figure 1 , Figure 3 , Figure 4 and Figure 5As shown, in some embodiments, the method further includes: two adjacent first sleeve sections 11 are connected by welding, and two adjacent second sleeve sections 21 are connected by welding. Welding forms a stable connection between the two adjacent first sleeve sections 11 and the two adjacent second sleeve sections 21, and welding is waterproof, enabling the outer and inner sleeves to withstand sufficient water pressure and ensuring no leakage.

[0034] In this embodiment, a first welding bevel 12 is provided at the top of the bottommost first sleeve section 11, and a first welding bevel 12 is provided at both ends of the middle first sleeve section 11. A second welding bevel 29 is provided at the top of the bottommost second sleeve section 21, and a second welding bevel 29 is provided at both ends of the middle second sleeve section 21. The welding between two adjacent first sleeve sections 11 and two adjacent second sleeve sections 21 adopts double-sided bevel welding. All welding must be continuous in order to ensure that the outer and inner protective sleeves can withstand sufficient water pressure and prevent water leakage.

[0035] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A casing structure for preventing collapse of pile foundations in karst formations, comprising an outer casing (1) and an inner casing (2), wherein the inner casing (2) is disposed inside the outer casing (1), the outer casing (1) comprises multiple first casing segments (11) connected end-to-end, and the inner casing (2) comprises multiple second casing segments (21) connected end-to-end, characterized in that, Also includes: Mounting component (23), which is disposed on the top of the second sleeve section (21); Lifting lug (25), said lifting lug (25) is welded to the mounting part (23); The first vertical reinforcing rib (13) is provided on the inner side of the first sleeve section (11). The slide (14) is provided on the first vertical reinforcing rib (13), and the slide (14) is adapted to the mounting part (23).

2. The slurry hole collapse protection casing structure for pile construction in karst stratum according to claim 1, characterized in that, Also includes: The first transverse reinforcing rib (15) is provided on the inner side of the first sleeve section (11), and the first transverse reinforcing rib (15) is connected to the first vertical reinforcing rib (13).

3. The slurry hole collapse protection casing structure for pile construction in karst stratum according to claim 1, characterized in that, Also includes: The second vertical reinforcing rib (26) is arranged circumferentially on the inner side of the second sleeve section (21).

4. The slurry ground pile construction hole collapse protection casing structure according to claim 3, characterized in that, Also includes: The second transverse reinforcing rib (27) is provided on the inner side of the second sleeve section (21), and the second transverse reinforcing rib (27) is connected to the second vertical reinforcing rib (26).

5. The sloughing hole protection casing structure for pile construction in karst stratum according to claim 1, characterized in that, Also includes: The first tapered section (16) is provided at the bottom of the first sleeve section (11) at the very bottom. The second tapering section (28) is provided at the bottom of the second sleeve section (21) at the very bottom.

6. The sloughing hole protection casing structure for pile construction in karst stratum according to claim 1, characterized in that, The two adjacent first sleeve sections (11) are connected by welding, and the two adjacent second sleeve sections (21) are connected by welding.

Images