Combined jet grouting pile reinforcing structure for railway bridge and culvert foundation reinforcement and construction method

Abstract

The invention discloses a combined jet grouting pile reinforcing structure for railway bridge and culvert foundation reinforcement and a construction method, and belongs to the technical field of jet grouting pile construction. The combined jet grouting pile reinforcing structure for railway bridge and culvert foundation strengthening comprises a sleeve used for supporting and protecting the inner wall of a grouting hole, the sleeve comprises a first half cylinder and a second half cylinder, the second half cylinder rotates on the inner wall of the first half cylinder, and multiple sets of limiting plates used for rotating the second half cylinder are arranged on the surface of the second half cylinder; the upper and lower adjacent sleeves are connected through a first extension plate and a second extension plate; when the drill rod is used for drilling the grouting hole, the sleeve is arranged on the surface of the drill rod in a sleeving mode and synchronously descends along with descending of the drill rod, so that the purpose of timely protection is achieved, the situation that in the drilling process, due to soil instability or hole collapse, the hole diameter of the grouting hole is decreased or the grouting hole is blocked is prevented, and it is guaranteed that follow-up grouting operation is conducted smoothly.

Description

Technical Field

[0001] This invention relates to the field of jet grouting construction technology, and in particular to a combined jet grouting pile reinforcement structure and construction method for strengthening railway bridge and culvert foundations. Background Technology

[0002] Jet grouting is a mature foundation reinforcement method widely used in geotechnical engineering, particularly in urban underground space development, tunnel engineering, and deep foundation pit support. Its basic principle is to use a high-pressure jet stream to forcibly mix cement grout with the soil, forming a cement-soil consolidation body with high strength and low permeability. This improves soil properties, achieving the goals of foundation reinforcement, increased bearing capacity, settlement control, and seepage prevention.

[0003] In the construction of rail transit and railway infrastructure, the foundation treatment of bridge and culvert sections is particularly critical. These sections often have complex geological conditions (such as the presence of weak soil layers, sand layers, karst development areas, etc.) and large superstructure loads, requiring extremely high standards for the uniformity, stability, and settlement control of the foundation. Therefore, jet grouting piles are used to strengthen the foundation.

[0004] In existing construction techniques, it is usually necessary to insert a sleeve into the grouting hole after drilling to prevent local collapse of the grouting hole, which would affect the construction of the jet grouting pile. However, the sleeve is inserted after the drill rod is pulled out. This means that during the time interval between drilling and sleeve insertion, and during the sleeve insertion process, the unstable soil layer on the hole wall is prone to peeling and hole collapse. This not only reduces the borehole diameter and depth, affecting the effective diameter and length of the subsequent jet grouting pile and reducing the reinforcement effect, but may also make it difficult to successfully lower the sleeve into place, or even require re-drilling. This increases the construction steps, prolongs the construction period, and increases the construction cost.

[0005] Therefore, this application proposes a combined jet grouting pile reinforcement structure and construction method that facilitates the installation of protective sleeves during drilling. Summary of the Invention

[0006] The purpose of this invention is to solve the problems in the prior art by proposing a combined jet grouting pile reinforcement structure and construction method for strengthening railway bridge and culvert foundations.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A combined jet grouting pile reinforcement structure for strengthening railway bridge and culvert foundations includes a sleeve for supporting and protecting the inner wall of the grouting hole. The sleeve includes a first half-cylinder and a second half-cylinder. The second half-cylinder rotates inside the first half-cylinder. Multiple sets of limiting plates for the rotation of the second half-cylinder are provided on the surface of the second half-cylinder. The upper and lower adjacent sleeves are connected by a first extension plate and a second extension plate.

[0008] In some embodiments, the limiting plate is arc-shaped, one end of the limiting plate rotates on the surface of the second half-cylinder, and the hinge end of the limiting plate is close to one side of the second half-cylinder. The length of the limiting plate matches the opening width of the first half-cylinder.

[0009] In some embodiments, the limiting plate is fixed to the surface of the second half-cylinder by a sliding plate and a connecting hole. The sliding plate is arc-shaped and slides horizontally on the surface of the limiting plate. The connecting hole is opened on the surface of the second half-cylinder. A first locking block that cooperates with the connecting hole is fixed on the side of the sliding plate facing the second half-cylinder.

[0010] In some embodiments, the first extension plate is fixed to the top of the first half-cylinder, the second extension plate is fixed to the top of the second half-cylinder, and the inner wall of the first extension plate is fixed with a slide rail connected to the second half-cylinder at the adjacent top.

[0011] In some embodiments, the diameter of the first extension plate is the same as the diameter of the first half-cylinder, the diameter of the second extension plate is the same as the diameter of the second half-cylinder, and the length of the first extension plate is the same as the opening width of the first half-cylinder.

[0012] In some embodiments, a plurality of second locking blocks that cooperate with the second extension plate are fixed at the bottom of the first half-cylinder. The second locking blocks are L-shaped and have their openings facing downwards.

[0013] In some embodiments, the surfaces of the first extension plate and the second extension plate are respectively provided with through holes, and the sleeve moves up and down with the drill rod via a pull rope.

[0014] In some embodiments, the sleeve is temporarily fixed in height by a support assembly comprising two bases and a clamping block for holding the sleeve, wherein a threaded rod is rotatably connected to the top of the bases and the clamping block is threaded onto the surface of the threaded rod.

[0015] In some embodiments, a support block is horizontally slidable on the top of the clamping block, and the top of the support block has a groove that mates with the through hole.

[0016] The construction method of combined jet grouting piles for reinforcing railway bridge and culvert foundations, based on the aforementioned combined jet grouting pile reinforcement structure for reinforcing railway bridge and culvert foundations, includes the following steps: S1. Drilling preparation: Measure the pile position before construction and nail it with bamboo sticks. After the drilling rig is in place, level and center the pile rig, and adjust the verticality of the pile rig to ensure that the drill rod is consistent with the pile position. S2. Drilling and Protection: The drill rod drives the high-pressure water jet to assist the drill bit in drilling, so as to drill a grouting hole with a diameter larger than that of the drill bit. At the same time as drilling, the sleeve is put on the surface of the drill rod and the sleeve is installed on the surface of the power head of the drilling machine by pulling rope, so that the sleeve descends with the drill rod, thereby protecting the grouting hole through the sleeve while drilling. S3. Grouting preparation: After drilling, the sleeve is temporarily fixed using the support assembly to separate the sleeve from the power head. Since the sleeve diameter is larger than the drill bit diameter, the power head can pull out the drill rod and drill bit separately. Then, the grouting pipe is inserted into the sleeve until the bottom of the hole. At this time, the lower end of the grouting pipe is located below the bottom of the sleeve. The power head is then connected to the top of the sleeve again by the pull rope. S4. Shotcrete Construction: High-pressure jet grouting is performed through the grouting pipe, with a pressure > 20 MPa and a flow rate > 50 L / min. Compressed air pressure is 0.5–0.7 MPa, flow rate > 1.5 m³ / min, lifting speed < 0.14 m / min, and uniform rotation speed. This process forms a cement-soil consolidation body, and the sleeve rises synchronously as the grouting pipe rises.

[0017] Compared with the prior art, the present invention provides a combined jet grouting pile reinforcement structure and construction method for strengthening railway bridge and culvert foundations, which has the following beneficial effects.

[0018] 1. This invention provides timely protection by placing a sleeve on the surface of the drill rod when drilling grouting holes, and lowering it synchronously with the drill rod as it descends. This prevents the grouting hole diameter from becoming smaller or becoming blocked due to soil instability or hole collapse during drilling, thus ensuring the smooth progress of subsequent grouting operations.

[0019] 2. In this invention, by setting the sleeve as a first half-cylinder and a second half-cylinder to form an open sleeve, it is easy to put it on the surface of the drill rod. By rotating the second half-cylinder, the opening of the first half-cylinder is closed, and the angle of the second half-cylinder is limited by the limiting plate to form a closed sleeve.

[0020] 3. By setting a first extension plate and a second extension plate, when connecting the upper and lower sleeves, the first half-cylinder corresponds to the lower second half-cylinder, and the bottom of the first half-cylinder is inserted into the surface of the second extension plate. Then, the upper second half-cylinder is rotated to close the first half-cylinder, so that the second half-cylinder corresponds to the first extension plate. During the rotation, the dovetail groove at the bottom of the second half-cylinder is inserted into the slide rail surface, thereby connecting the upper and lower adjacent sleeves, which facilitates the quick connection of the upper and lower sleeves.

[0021] Other advantages, objectives and features of the invention will be set forth in part in the description which follows; and in part will be apparent to those skilled in the art upon examination of the following description; or may be learned from practice of the invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the drilling process of the present invention in use.

[0023] Figure 2 This is a front view structural diagram of the present invention.

[0024] Figure 3 This is a schematic diagram of the exploded structure of the present invention.

[0025] Figure 4 This is a schematic diagram of the second half-cylinder in the open state in this invention.

[0026] Figure 5 This is a schematic diagram of the limit plate in the open state in this invention.

[0027] Figure 6 This is a top view cross-sectional structural diagram of the present invention.

[0028] Figure 7 This is a schematic diagram of the connection state structure of the present invention.

[0029] Figure 8 This is a schematic diagram of the first cross-sectional structure of the connection state of the present invention.

[0030] Figure 9 This is a second cross-sectional structural diagram of the connection state of the present invention.

[0031] Figure 10 For the present invention Figure 8 Enlarged structural diagram at point A in the middle.

[0032] Figure 11 For the present invention Figure 9 Enlarged structural diagram at point B.

[0033] Figure 12 This is a partial structural diagram of the present invention.

[0034] Figure 13 This is a schematic diagram of the supporting component in use in this invention.

[0035] Figure 14 This is a schematic diagram of the rotary spraying state of the present invention.

[0036] In the picture: 1. First half-cylinder; 2. Second half-cylinder; 201. Limiting plate; 2011. Slide plate; 2012. First locking block; 2013. Connecting hole; 3. First extension plate; 301. Slide rail; 4. Second extension plate; 401. Second locking block; 5. Through hole; 6. Pull rope; 7. Support assembly; 701. Base; 702. Clamping block; 703. Threaded rod; 704. Support block; 8. Grouting hole; 9. Drill rod; 10. Grouting pipe; 11. Cement-soil consolidation body. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0038] Reference Figure 1-14 The combined jet grouting pile reinforcement structure for strengthening railway bridge and culvert foundations includes a sleeve for supporting and protecting the inner wall of the grouting hole 8. The sleeve includes a first half-cylinder 1 and a second half-cylinder 2. The first half-cylinder 1 is larger than half a circle, and the second half-cylinder 2 is half a circle. The diameter of the second half-cylinder 2 is smaller than the diameter of the first half-cylinder 1. The second half-cylinder 2 rotates on the inner wall of the first half-cylinder 1. The inner wall of the first half-cylinder 1 and the surface of the second half-cylinder 2 are provided with guide rails for the rotation of the second half-cylinder 2. The surface of the second half-cylinder 2 is provided with multiple sets of limiting plates 201 for the rotation of the second half-cylinder 2. The height of the sleeve is the same as the height of the drill rod 9.

[0039] It is understandable that when drilling the grouting hole 8 using drill rod 9, the sleeve is fitted onto the surface of drill rod 9 and descends synchronously with the descent of drill rod 9. The diameter of the sleeve matches the diameter of the grouting hole 8, and the inner diameter of the sleeve is larger than the diameter of the drill bit of drill rod 9. The drill bit uses a high-pressure water jet assisted drill bit for drilling. The high-pressure water jet assisted drill bit (the principle of the high-pressure water jet assisted drill bit is that while the drilling rig is rotating and drilling, high-pressure water is delivered to the drill bit through drill rod 9. The high-pressure fluid is ejected from the side nozzle at extremely high speed, forming a high-speed jet that directly impacts, cuts and scours the soil or weak rock on the hole wall, causing it to disintegrate, peel off and be carried out of the hole by circulating mud, thereby further expanding the hole diameter beyond the standard hole diameter cut by the mechanical drill bit) is existing technology, so it will not be described in detail. When installing the sleeve, the second half-cylinder 2 is rotated into the first half-cylinder 1 to form an open sleeve, which is convenient to fit onto the surface of the drill rod 9. By rotating the second half-cylinder 2, the opening of the first half-cylinder 1 is closed, and the angle of the second half-cylinder 2 is limited by the limiting plate 201. The sleeve is then inserted into the grouting hole 8 and descends with the drill rod 9, thereby achieving the purpose of timely protection and preventing the diameter of the grouting hole 8 from becoming smaller or blocked due to soil instability or hole collapse during drilling, ensuring the smooth progress of subsequent grouting operations. By setting a guide rail, the second half-cylinder 2 can be rotated stably on the inner wall of the first half-cylinder 1, and the height between the second half-cylinder 2 and the first half-cylinder 1 is limited.

[0040] Specifically, the limiting plate 201 is arc-shaped and matches the surface diameter of the second half-cylinder 2. One end of the limiting plate 201 rotates on the surface of the second half-cylinder 2, and the hinge end of the limiting plate 201 is close to one side of the second half-cylinder 2. The length of the limiting plate 201 matches the opening width of the first half-cylinder 1. The limiting plate 201 is fixed to the surface of the second half-cylinder 2 via the sliding plate 2011 and the connecting hole 2013. The sliding plate 2011 is arc-shaped and slides horizontally on the surface of the limiting plate 201. The connecting hole 2013 is opened on the surface of the second half-cylinder 2. A first locking block 2012 that cooperates with the connecting hole 2013 is fixed on the side of the sliding plate 2011 facing the second half-cylinder 2. The second locking block 401 is L-shaped.

[0041] Understandably, when the second half-cylinder 2 rotates to a closed state with the first half-cylinder 1, the hinged end of the limiting plate 201 limits the rotation angle of the second half-cylinder 2, ensuring that both sides of the second half-cylinder 2 are located on the inner wall of the first half-cylinder 1. As the limiting plate 201 rotates, it comes into contact with the surface of the second half-cylinder 2. At this time, both ends of the limiting plate 201 abut against the opening sides of the first half-cylinder 1, thus preventing the first half-cylinder 1 from rotating in any direction. Simultaneously, when the grouting hole 8 collapses, the thrust acting on the surface of the second half-cylinder 2 and the limiting plate 201 easily causes deformation of the second half-cylinder 2. At this time, the limiting plate... The two ends of the limiting plate 201 abut against the two sides of the first half-cylinder 1, sharing the pressure of the second half-cylinder 2 and effectively increasing the support strength of the second half-cylinder 2; preventing the second half-cylinder 2 from being excessively deformed and affecting the opening and closing of the second half-cylinder 2; when the limiting plate 201 is in contact with the surface of the second half-cylinder 2, the first locking block 2012 is inserted into the connecting hole 2013, and by moving the sliding plate 2011, the L-shaped first locking block 2012 is locked onto the inner wall of the second half-cylinder 2, thereby limiting the rotation of the limiting plate 201, preventing the limiting plate 201 from rotating, and keeping the limiting plate 201 in contact with the second half-cylinder 2.

[0042] Specifically, the upper and lower adjacent sleeves are connected by a first extension plate 3 and a second extension plate 4. The first extension plate 3 is fixed to the top of the first half-cylinder 1, and the second extension plate 4 is fixed to the top of the second half-cylinder 2. The inner wall of the first extension plate 3 is fixed with a slide rail 301 that connects to the adjacent top of the second half-cylinder 2. The bottom of the second half-cylinder 2 is provided with a dovetail groove that cooperates with the slide rail 301. The diameter of the first extension plate 3 is the same as the diameter of the first half-cylinder 1, the diameter of the second extension plate 4 is the same as the diameter of the second half-cylinder 2, the length of the first extension plate 3 is the same as the opening width of the first half-cylinder 1, the first extension plate 3 is used to cooperate with the adjacent second half-cylinder 2, and the second extension plate 4 is used to cooperate with the adjacent first half-cylinder 1. The bottom height of the second half-cylinder 2 is higher than the bottom height of the first half-cylinder 1, and the height of the first extension plate 3 is higher than the height of the second extension plate 4.

[0043] It is understandable that by setting the first extension plate 3 and the second extension plate 4, when connecting the upper and lower sleeves, the upper sleeve is inserted into the surface of the lower first extension plate 3 and the second extension plate 4 for initial connection. Since the diameter of the first half-cylinder 1 is larger than the diameter of the second half-cylinder 2, when inserted, the second half-cylinder 2 is located on the inner wall of the first half-cylinder 1, and the first half-cylinder 1 is in an open state, which makes it easy to fit on the surface of the drill rod 9, so that the first half-cylinder 1 corresponds to the lower second half-cylinder 2. The bottom of the first half-cylinder 1 is inserted into the surface of the second extension plate 4. Then, the upper second half-cylinder 2 is rotated to close the first half-cylinder 1, so that the second half-cylinder 2 corresponds to the first extension plate 3. During the rotation, the dovetail groove at the bottom of the second half-cylinder 2 is inserted into the surface of the slide rail 301, thereby connecting the upper and lower adjacent sleeves. At the same time, after insertion, the upper first half-cylinder 1 abuts against the top of the lower first half-cylinder 1. Since the length of the first extension plate 3 is the same as the opening width of the first half-cylinder 1, the rotation of the upper first half-cylinder 1 can be limited. By setting the height of the first extension plate 3 to be higher than the height of the second extension plate 4, when the first half-cylinder 1 is inserted into the surface of the second extension plate 4, the second half-cylinder 2 is located above the second extension plate 4, thus avoiding interference between the second half-cylinder 2 and the second extension plate 4.

[0044] Specifically, the bottom of the first half-cylinder 1 is fixed with a plurality of second locking blocks 401 that cooperate with the second extension plate 4. The second locking blocks 401 are L-shaped and have their openings facing downwards.

[0045] It is understandable that by setting the second locking block 401, when inserting the first half-cylinder 1, the second locking block 401 is inserted into the top of the second extension plate 4, so that the first half-cylinder 1 can be kept in a vertical state, which makes it easier to operate and rotate the second half-cylinder 2.

[0046] Specifically, the first extension plate 3 and the second extension plate 4 are respectively provided with through holes 5. The two through holes 5 are at the same height and are both located below the slide rail 301. The sleeve moves up and down with the drill rod 9 via the pull rope 6. The upper end of the pull rope 6 is attached to the power head surface of the drill rig via a hook, and the lower end of the pull rope 6 is attached to the two through holes 5 via a hook.

[0047] It is understandable that by setting through holes 5 and pull ropes 6, the pull ropes 6 are hung in the through holes 5 of the topmost sleeve. During drilling, the power head drives the drill rod 9 to descend. Under the action of gravity, the sleeve follows the power head to descend, thereby achieving the purpose of timely protection. During jet grouting, the nozzle is driven to rise gradually, and the sleeve is pulled out from the grouting hole 8.

[0048] Specifically, the sleeve is temporarily fixed in height by the support assembly 7. The support assembly 7 includes two bases 701 and a clamping block 702 for clamping the sleeve. The two bases 701 are semi-circular and are fixedly connected by bolts. A threaded rod 703 is rotatably connected to the top of the base 701. The clamping block 702 is threadedly connected to the surface of the threaded rod 703. The end of the clamping block 702 facing the sleeve is provided with anti-slip texture.

[0049] Understandably, since the pull rope 6 of the traction sleeve needs to be removed when splicing the upper and lower sleeves, the sleeve is in a suspended state at this time and needs to be fixed. Therefore, by setting the support component 7, before removing the pull rope 6, the threaded rod 703 is rotated to drive the clamping block 702 to abut against the surface of the sleeve, thereby clamping and fixing the sleeve to prevent it from falling and facilitating the splicing of the sleeve; the base 701 is placed on top of the grouting hole 8 and the two bases 701 are connected with bolts.

[0050] Specifically, a support block 704 slides horizontally on the top of the clamping block 702, and the top of the support block 704 has a groove that matches the through hole 5.

[0051] Understandably, when the grouting hole 8 is drilled, there is a gap between the bottom of the sleeve and the bottom of the grouting hole 8, and the sleeve is suspended in the air for the start of the jet grouting pile. However, when the drill rod 9 is replaced with the grouting pipe 10, it takes a long time. At this time, the fixing effect of the sleeve by the clamping block 702 deteriorates over time and is prone to loosening, causing the sleeve to fall. Therefore, by setting the support block 704, after the sleeve is clamped, the support block 704 is inserted into the through hole 5, thereby preventing the clamping block 702 from loosening and causing the sleeve to fall.

[0052] This embodiment also provides a construction method for combined jet grouting piles for reinforcing railway bridge and culvert foundations. Based on the above-mentioned combined jet grouting pile reinforcement structure for reinforcing railway bridge and culvert foundations, the method includes the following steps: S1. Drilling preparation: Before construction, measure the pile position and nail it with bamboo sticks, one stick for each pile, to ensure that the center displacement deviation of the pile hole is less than 50mm. After the drilling rig is in place, level and center the pile rig, and adjust the verticality of the pile rig to ensure that the drill rod 9 is consistent with the pile position. Check the length of the drill rod 9 and mark the depth line next to the drilling tower with red paint to ensure that the bottom elevation of the hole meets the design depth. S2. Drilling and Protection: The drill rod 9 drives the high-pressure water jet to assist the drill bit in drilling, so as to drill a grouting hole 8 that is larger than the diameter of the drill bit. At the same time as drilling, the sleeve is placed on the surface of the drill rod 9, and the sleeve is installed on the surface of the power head of the drilling machine by the pull rope 6. The sleeve descends with the drill rod 9, so that the grouting hole 8 is protected by the sleeve while drilling. During the descent of the sleeve, the bottom of the sleeve is kept at a distance from the drill bit. S3. Grouting preparation: After drilling, the sleeve is temporarily fixed using the support component 7 to separate the sleeve from the power head. Since the diameter of the sleeve is larger than the diameter of the drill bit, the power head can pull out the drill rod 9 and the drill bit separately. Then, the grouting pipe 10 is inserted into the sleeve until the bottom of the hole. At this time, the lower end of the grouting pipe 10 is located below the bottom of the sleeve. The power head is then connected to the top of the sleeve again by the pull rope 6. S4. Shotcrete Construction: High-pressure jet grouting is performed through grouting pipe 10, with pressure > 20 MPa and flow rate > 50 L / min. Compressed air pressure is 0.5–0.7 MPa, flow rate > 1.5 m³ / min, lifting speed < 0.14 m / min, and uniform rotation speed. This process forms a cement-soil consolidated body 11. As the grouting pipe 10 rises, the sleeve rises synchronously.

[0053] In this invention, when installing the sleeve, two bases 701 are placed on top of the grouting hole 8 and connected by bolts. The second half-cylinder 2 is rotated into the first half-cylinder 1 to form an open sleeve, which is convenient for fitting onto the surface of the drill rod 9. By rotating the second half-cylinder 2, the opening of the first half-cylinder 1 is closed, and the angle of the second half-cylinder 2 is limited by the limiting plate 201, so that the pull rope 6 is hung in the through hole 5. The sleeve is inserted into the grouting hole 8. During drilling, the power head drives the drill rod 9 to descend. Under the action of gravity, the sleeve follows the power head to descend, thereby achieving the purpose of timely protection and preventing the diameter of the grouting hole 8 from becoming smaller or blocked due to soil instability or hole collapse during drilling, ensuring the smooth progress of subsequent grouting operations. When connecting the upper and lower sleeves, the first half-cylinder 1 is aligned with the lower second half-cylinder 2. The bottom of the first half-cylinder 1 is inserted into the surface of the second extension plate 4. Then, the upper second half-cylinder 2 is rotated to align with the first half-cylinder 2. 1. When closed, the second half-cylinder 2 aligns with the first extension plate 3. During rotation, the dovetail groove at the bottom of the second half-cylinder 2 is inserted into the surface of the slide rail 301, thereby connecting the upper and lower adjacent sleeves. Simultaneously, after insertion, the upper first half-cylinder 1 abuts against the top of the lower first half-cylinder 1. Since the length of the first extension plate 3 is the same as the opening width of the first half-cylinder 1, the rotation of the upper first half-cylinder 1 can be limited, completing the connection of the upper and lower sleeves. The pull rope 6 is hung on the top of the uppermost sleeve, causing the spliced ​​sleeve to continuously descend. When splicing the sleeve, the threaded rod 703 is rotated, causing the clamping block 702 to abut against the sleeve surface, thereby clamping and fixing the sleeve to prevent it from falling and facilitating the splicing of the sleeve. When the grouting hole 8 is drilled, a support block 704 is set. After clamping the sleeve, the support block 704 is inserted into the through hole 5, thereby preventing the clamping block 702 from loosening and causing the sleeve to fall.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0056] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A combined jet grouting pile reinforcement structure for strengthening railway bridge and culvert foundations, characterized in that, Includes a sleeve for supporting and protecting the inner wall of the grouting hole (8), the sleeve including a first half-cylinder (1) and a second half-cylinder (2), the second half-cylinder (2) being rotatably connected to the inner wall of the first half-cylinder (1), and the surface of the second half-cylinder (2) being provided with multiple sets of limiting plates (201) for limiting the rotation of the second half-cylinder (2). The upper and lower adjacent sleeves are connected by a first extension plate (3) and a second extension plate (4).

2. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 1, characterized in that, The limiting plate (201) is arc-shaped. One end of the limiting plate (201) is rotatably connected to the surface of the second half-cylinder (2), and the hinge end of the limiting plate (201) is close to one side of the second half-cylinder (2). The length of the limiting plate (201) matches the opening width of the first half-cylinder (1).

3. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 1, characterized in that, The limiting plate (201) is fixed to the surface of the second half cylinder (2) by the sliding plate (2011) and the connecting hole (2013). The sliding plate (2011) is arc-shaped and is horizontally slidably connected to the surface of the limiting plate (201). The connecting hole (2013) is opened on the surface of the second half cylinder (2). A first locking block (2012) that cooperates with the connecting hole (2013) is fixed on the side of the sliding plate (2011) facing the second half cylinder (2).

4. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 1, characterized in that, The first extension plate (3) is fixed to the top of the first half cylinder (1), the second extension plate (4) is fixed to the top of the second half cylinder (2), and the inner wall of the first extension plate (3) is fixed with a slide rail (301) connected to the adjacent top of the second half cylinder (2).

5. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 1, characterized in that, The diameter of the first extension plate (3) is the same as the diameter of the first half-cylinder (1), the diameter of the second extension plate (4) is the same as the diameter of the second half-cylinder (2), and the length of the first extension plate (3) is the same as the opening width of the first half-cylinder (1).

6. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 1, characterized in that, The bottom of the first half-cylinder (1) is fixed with a plurality of second locking blocks (401) that cooperate with the second extension plate (4). The second locking blocks (401) are L-shaped and have their openings facing downwards.

7. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 1, characterized in that, The first extension plate (3) and the second extension plate (4) are respectively provided with through holes (5), and the sleeve moves up and down with the drill rod (9) via the pull rope (6).

8. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 1, characterized in that, The sleeve is temporarily fixed in height by a support assembly (7), which includes two bases (701) and a clamping block (702) for clamping the sleeve. A threaded rod (703) is rotatably connected to the top of the base (701), and the clamping block (702) is threadedly connected to the surface of the threaded rod (703).

9. The combined jet grouting pile reinforcement structure for railway bridge and culvert foundation strengthening according to claim 8, characterized in that, The top of the clamping block (702) is horizontally slidably connected to a support block (704), and the top of the support block (704) has a groove that matches the through hole (5).

10. A construction method for combined jet grouting piles for reinforcing railway bridge and culvert foundations, based on the combined jet grouting pile reinforcement structure for reinforcing railway bridge and culvert foundations as described in any one of claims 1-9, characterized in that... Includes the following steps: S1. Drilling preparation: Before construction, measure the pile position and nail it with bamboo sticks. After the drilling machine is in place, level and center the pile machine and adjust the verticality of the pile machine to ensure that the drill rod (9) is consistent with the pile position. S2. Drilling and Protection: The drill rod (9) drives the high-pressure water jet to assist the drill bit in drilling, so as to drill a grouting hole (8) larger than the diameter of the drill bit. At the same time as drilling, the sleeve is placed on the surface of the drill rod (9), and the sleeve is installed on the surface of the power head of the drilling machine by the pull rope (6), so that the sleeve descends with the drill rod (9), thereby protecting the grouting hole (8) through the sleeve while drilling. S3. Grouting preparation: After drilling, the sleeve is temporarily fixed by the support assembly (7) to separate the sleeve from the power head. Since the diameter of the sleeve is larger than the diameter of the drill bit, the power head can pull out the drill rod (9) and the drill bit separately. Then, the grouting pipe (10) is inserted into the sleeve until the bottom of the hole. At this time, the lower end of the grouting pipe (10) is located below the bottom of the sleeve. The power head is connected to the top of the sleeve again by the pull rope (6). S4. Grouting construction: High-pressure jet grouting is carried out through the grouting pipe (10), with pressure >20MPa, flow rate >50L / min, compressed air pressure 0.5~0.7MPa, flow rate >1.5m³ / min, lifting speed <0.14m / min, and uniform rotation speed to carry out jet grouting construction of the jet grouting pile, forming a cement-soil solidified body (11). While the grouting pipe (10) rises, the sleeve rises synchronously.

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