Karst development rock mass broken deep water high scour pile foundation toughening system and construction method

Abstract

The application provides a karst development rock mass broken deep water high scour pile foundation toughening system and a construction method, a steel casing and a glass fiber sleeve are arranged outside the pile foundation, a micro pile is arranged outside the steel casing and connected with the steel casing through an annular fixing plate and a connecting rod, an annular pouring flow guide groove is arranged at the bottom of the steel casing and connected with a grouting anchor rod and a fixing sleeve, a complex fiber solid waste base cement mortar is poured to make the slurry enter the cavity and the fissure of the karst development broken rock mass along the grouting anchor rod to fill and reinforce, meanwhile, modified foam concrete is used to fill and compact the karst cavity around the pile foundation; an annular steel plate bottom board stone cage frame is arranged outside the steel casing, an annular constraint cavity is formed through the micro pile positioning, a steel wire cable and a stone cage steel wire mesh, and the annular constraint cavity is filled with riprap. The application realizes the reinforcement and protection of the pile body, the rock mass around the pile and the peripheral protection structure, improves the overall stability and the durability and protection capacity of the pile foundation in the complex underwater environment, and has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of civil engineering, and in particular to a toughening system and construction method for deep-water high-scour pile foundations in karst-developed rock masses. Background Technology

[0002] With the continuous expansion of bridge, wharf, offshore wind power foundation, and other water-related engineering projects, pile foundations, as an important foundation type that bears the load of the superstructure and transfers the load to the deep foundation, are widely used in engineering construction under complex water conditions and soft soil conditions. In actual construction and operation, some pile foundations need to be in an underwater environment for extended periods, especially in rivers, lakes, nearshore areas, and areas with large tidal ranges. The pile body is easily affected by factors such as water flow erosion, wave action, impact from floating objects, and water erosion. Simultaneously, in some karst, weak interlayer, or geologically complex areas, the bearing conditions of the surrounding strata vary significantly, and local areas of the pile body may also be affected by scouring, void development, and foundation instability. Therefore, for both existing and newly constructed pile foundations, improving the stability and durability of the pile body in complex underwater environments and adverse geological conditions has become a key issue that needs to be considered during the construction and maintenance of water-related pile foundation projects.

[0003] Currently, for the protection and reinforcement of underwater pile foundations, engineering projects typically employ methods such as adding steel casings, encasing the pile in concrete or underwater grouting materials, installing steel sleeves and reinforcement components, and adding micropiles or grouting anchors to treat locally damaged areas of the pile or the surrounding soil. Among these, steel casings and steel sleeves can improve the pile's external resistance to scour and impact to a certain extent; underwater grouting materials can be used to fill voids and localized defects around the pile; and micropiles and grouting anchors are mainly used to improve the stress conditions of the surrounding soil. For pile foundations with karst development, localized cavities, or scour pits, it is usually necessary to combine underwater protection measures such as riprap and gabions to backfill and protect the area around the pile. In existing engineering practice, the above measures are often adopted according to the specific damage conditions. The construction process involves multiple stages, including underwater positioning, component installation, grouting, and soil reinforcement, placing high demands on the construction environment and operational precision.

[0004] However, traditional underwater pile foundation protection and reinforcement methods still have certain limitations in practical applications. On the one hand, the underwater construction environment is complex, with low visibility and limited working space. Steel casings, hoop sleeves, and other reinforcement components are prone to positioning deviations, insecure installations, or loose connections during installation, making it difficult to form a stable and reliable overall load-bearing relationship between the protective components and the pile body. On the other hand, underwater grouting is easily affected by water flow disturbances, grout diffusion, and limited pouring space, making it difficult to ensure that the grout fully fills the target area, and local voids and weak areas may still exist. For areas with karst development or large-scale scouring and erosion around the pile foundation, relying solely on external pile protection often cannot simultaneously solve the problems of pile protection and foundation bearing stability. Furthermore, traditional protective structures typically have many components, complex construction procedures, difficult underwater installation, and inconvenient post-installation maintenance. Under complex geological conditions and long-term underwater service, their overall stability and durability still require further improvement. Therefore, it is necessary to further optimize existing construction and protection methods to meet the needs of pile foundation protection and reinforcement under complex underwater environments and adverse geological conditions. Summary of the Invention

[0005] The purpose of this invention is to provide a toughening system and construction method for karst-developed, fractured, deep-water, high-scour pile foundations that solves the above-mentioned technical problems.

[0006] To address the aforementioned technical problems, this invention provides a construction method for a toughening system for deep-water, high-scour pile foundations in karst-developed, fractured rock masses, comprising the following steps: Step 1: Construct a cofferdam around the pile foundation; Step 2: Insert the grouting anchor into the fractured rock mass with karst development, and align the end of the grouting anchor with the fixed sleeve of the annular casting guide channel. Step 3: Place the steel casing on the outside of the bottom of the pile foundation, so that the top of the steel casing is located at the predetermined position on the outside of the pile foundation; Step 4: Connect the fixed sleeve to the grouting anchor rod and connect the fixed sleeve to the annular pouring guide channel. Establish a grouting channel from the annular pouring guide channel to the grouting anchor rod through the grouting hole and the fixed sleeve. Step 5: Arrange micropiles around the circumference of the steel casing so that the micropiles are inserted into the karst-developed and fractured rock mass surrounding the pile foundation; Step 6: First, install the annular fixing plate, connecting the annular fixing plate and the steel casing with a connecting rod, and then pass the micropile through the micropile insertion hole at the annular fixing plate. Step 7: Pour cement mortar into the annular pouring guide channel, so that the cement mortar enters the grouting anchor through the grouting hole and diffuses and fills the cavities and fissures of the karst-developed fractured rock mass. At the same time, use modified foamed concrete to fill and compact the karst cavities around the pile foundation. Step 8: Place the annular steel plate bottom plate gabion frame on the outside of the steel casing, so that the bottom plate rests on the top of the annular fixed plate, and let the micropile pass through the micropile insertion hole; lay gabion wire mesh around the bottom plate to form a circumferential constraint cavity, and fill the circumferential constraint cavity with riprap. Step 9: Place the fiberglass sleeve on the outside of the pile foundation, so that the bottom of the fiberglass sleeve rests in the fiberglass sleeve support groove on the top of the steel casing. Place the fixing lugs on the outer periphery of the fiberglass sleeve in the fixing lug support groove of the steel casing. Place the clamping plate on the outer periphery of the fiberglass sleeve in the clamping plate reserved hole of the steel casing. At the same time, fill the space between the fiberglass sleeve and the pile foundation with underwater epoxy grouting material, and set a fixing ring hoop on the outside of the fiberglass sleeve. Step 10: After the grouting reinforcement and connection of all protective structures are completed, dismantle the cofferdam.

[0007] Furthermore, in step nine, multiple rows of positioning elements are evenly arranged radially on the inner wall of the fiberglass sleeve, and the positioning elements abut against the outer wall of the pile foundation.

[0008] Furthermore, in step nine, the fixed ear plate support groove is set between two adjacent mating ear plates, and several vertical clamping plates are evenly provided on the outer side of the steel casing along the circumference. The vertical clamping plates are evenly provided with perforations on their sides, and the top of the vertical clamping plates is provided with a tensioning ear plate. The vertical clamping plates are located above the plane where the annular fixed plate and connecting rod are located.

[0009] Furthermore, in step four, a fixed sleeve penetrating the inner wall is provided on the outer side of the annular casting guide channel. The top of the inner side of the fixed sleeve is provided with a grouting hole and a first insertion hole. The bottom plate of the guide channel is located at the bottom of the annular casting guide channel, and the bottom plate of the guide channel is provided with an insertion port. The insertion port and the first insertion hole are vertically aligned so that the pin passes through the first insertion hole and the insertion port in sequence for fixation.

[0010] Furthermore, in step eight, the fixing ring is connected to the base plate through several columns, and a gabion wire mesh is provided between the fixing ring, the columns, and the base plate. Multiple rings are evenly distributed around the fixing ring in the circumferential direction. The base plate has a central reserved opening in the center, and multiple through micro pile insertion holes are provided above the top of the base plate.

[0011] Furthermore, multiple vertical arc-shaped ring plates are evenly arranged around the central reserved opening, and guide positioning slots matching the vertical locking plates are formed between adjacent vertical arc-shaped ring plates. Multiple second insertion holes are provided at the center of the top of the bottom plate, and the second insertion holes are perpendicularly connected to the guide positioning slots. A vertical rib plate is provided at the center of the outer side of the vertical arc-shaped ring plate, and a sleeve opening is provided at the intersection of the vertical rib plate and the vertical arc-shaped ring plate. A sleeve groove is evenly provided on the outer side of the vertical arc-shaped ring plate, and the sleeve groove and the sleeve opening are connected on the same plane.

[0012] Furthermore, the vertical clamping plate is placed in the guide positioning slot and the second insertion hole, and the annular sleeve passes through the sleeve opening in sequence and is clamped in the sleeve groove.

[0013] Furthermore, the micropile passes through the corresponding annular fixing plate and micropile insertion hole in sequence, and is fixed with the lower fixing bolt and the upper fixing bolt. The base plate rests on the top of the annular fixing plate, and the ring is fixed to the tensioning ear plate by steel wire cable.

[0014] Furthermore, in step seven, the modified foamed concrete comprises 45%-52% cement, 22%-30% slag powder, 14%-20% basalt powder, and 4%-8% bamboo-based biochar; the modified foamed concrete also contains composite fibers, including basalt fiber and natural plant fiber, wherein the volume ratio of basalt fiber to natural plant fiber is 1:1.5-1:2.5, and the total fiber volume content is 0.3%-0.6%.

[0015] This invention also discloses a toughening system for deep-water, high-scour pile foundations in karst-developed, fractured rock masses, which is obtained by construction according to the construction method of the toughening system for deep-water, high-scour pile foundations in karst-developed, fractured rock masses.

[0016] The beneficial effects of this invention are as follows: 1. This invention employs a steel casing, a fiberglass sleeve, and underwater epoxy grout to form a composite protective structure for the pile body. The fiberglass sleeve is fitted onto the outside of the pile foundation and positioned and locked using the fiberglass sleeve support groove, fixing lug, clamping plate, connecting lug, and screws and nuts on the top of the steel casing. At the same time, underwater epoxy grout is filled between the fiberglass sleeve and the pile foundation, forming a close composite protective interface between the fiberglass sleeve and the outer wall of the pile foundation. The overall constraint of the fiberglass sleeve is enhanced by fixing rings, thereby improving the integrity of the outer structure of the pile body and enhancing the pile body's protective ability against complex underwater environments and water erosion.

[0017] 2. This invention utilizes a ring-shaped collaborative connection structure between micropiles and steel casings. Through a ring-shaped fixing plate, upper fixing bolts, lower fixing bolts, and connecting rods, the circumferentially arranged micropiles are connected to the steel casing. This allows the micropiles to not only be inserted into the surrounding karst-developed and fractured rock mass to form auxiliary reinforcement components, but also to form an integral load-bearing and scour-resistant structure with the steel casing. Combined with vertical clamping plates, ring-shaped hoops, and related positioning components to constrain the external structure, this enhances the overall stability of the protection system around the pile foundation and reduces the impact of water erosion on the surrounding rock mass, leading to scouring and local instability.

[0018] 3. This invention utilizes an annular casting guide channel, a fixed sleeve, and grouting anchors to form a directional grouting channel. By setting the annular casting guide channel on the outer side of the bottom of the steel casing and connecting it to the grouting anchors using the fixed sleeve, the cement mortar injected into the annular casting guide channel can enter the grouting anchors through the grouting holes and then diffuse and fill the cavities and fissures inside the karst-developed fractured rock mass. At the same time, the bottom plate of the guide channel and the fixed sleeve are connected and fixed using insertion holes, insertion ports, and pins, which can centrally organize the grouting path, thereby improving the grout delivery capacity to the defect areas inside the fractured rock mass around the pile, realizing the filling and reinforcement of karst cavities, fissures, and loose areas, and improving the integrity of the fractured rock mass around the pile foundation.

[0019] 4. This invention uses fiber-reinforced solid waste-based modified foamed concrete to fill and compact the karst cavities around the pile foundation. The cementitious material system consists of cement, slag powder, basalt powder, and bamboo-based biochar, and is further incorporating basalt fiber and natural plant fiber, giving the modified foamed concrete both karst cavity filling and fiber composite toughening functions. Utilizing the good fluidity and filling capacity of foamed concrete, the overall integrity of the karst cavity and the overall stress conditions of the rock mass surrounding the pile foundation are improved. Furthermore, the synergistic effect of fiber reinforcement and solid waste-based lightweight materials is leveraged to reduce the self-weight of the filling material while improving its crack resistance, thus solving the problems of heavy self-weight and easy cracking of traditional concrete filling karst cavities.

[0020] 5. This invention utilizes a ring-shaped steel plate base plate gabion frame and riprap to form a ring-shaped anti-scour protection structure around the pile foundation. The ring-shaped containment space is formed by the base plate, fixing ring, columns, vertical ribs, vertical arc-shaped ring plate, and gabion wire mesh. Steel wire cables connect the ring to the fixing lugs, forming circumferential constraints on the gabion wire mesh and the internal riprap, allowing the riprap to be stably arranged around the pile foundation. At the same time, the gabion frame is fitted outside the steel casing and rests on the top of the ring fixing plate, so that the gabion protection structure, the steel casing, and the micropiles form an integral whole. This enhances the protection capability of the surrounding overburden and scour area, reduces the direct scouring effect of water flow on the surrounding soil and rock, and forms a multi-layered composite protection system together with internal grouting toughening and external steel casing protection. Attached Figure Description

[0021] Figure 1 This is a construction elevation view of a toughening system for pile foundations in deep water with high scour and fractured rock masses in karst development. Figure 2 This is a plan view of the annular casting guide channel; Figure 3 This is a three-dimensional schematic diagram of the detailed structure of the top of the steel casing; Figure 4 This is a three-dimensional schematic diagram of a gabion frame with a ring-shaped steel plate base. Figure 5 This is a three-dimensional schematic diagram of the construction of the connection between the annular steel plate base gabion frame and the steel casing; Figure 6 This is a three-dimensional schematic diagram of the annular casting guide channel; Figure 7 This is a three-dimensional schematic diagram of the connection between the fiberglass sleeve and the top of the steel casing; Figure 8 This is a three-dimensional schematic diagram of a fiberglass sleeve; Figure 9 This is a three-dimensional schematic diagram of the bottom structure of the annular steel plate gabion frame; Figure 10 This is a three-dimensional schematic diagram of the connection between the micropile and the steel casing; Figure 11 This is a three-dimensional schematic diagram of the construction of a toughening system for pile foundations in deep water with high scour and fractured rock masses in karst development. Figure 12 This is an elevation view of the steel casing structure; Figure 13 This is a three-dimensional schematic diagram of the connection between the annular casting guide channel and the steel casing.

[0022] Attached reference numerals: 1. Pile foundation; 2. Fiberglass sleeve; 3. Central reserved opening; 4. Screw; 5. Fixing ear plate; 6. Guide positioning bayonet; 7. Nut; 8. Steel casing; 9. Hoop opening; 10. Steel wire cable; 11. Fixing ring; 12. Column; 13. Upper fixing bolt; 14. Annular fixing plate; 15. Lower fixing bolt; 16. Cement mortar; 17. Annular cast-in-place diversion channel; 18. Micropile; 19. Grouting anchor; 20. Fixing sleeve; 21. Karst-developed fractured rock mass; 22. Base plate; 23. Ring sleeve; 24. Vertical rib plate; 25. Annular hoop; 26. Fixing hoop; 27. Tie-in ear plate; 28. Underwater epoxy grouting material; 29. ​​Positioning component; 30. Gabion wire mesh; 31. Vertical clamping plate; 32. Vertical arc-shaped ring plate; 33. Fixed ear plate support groove; 34. Clamping plate reserved hole; 35. Fiberglass sleeve support groove; 36. Top of steel casing; 37. Butt joint ear plate; 38. Micropile insertion hole; 39. Rock dumping; 40. Pin; 41. Drainage channel bottom plate; 42. Grouting hole; 43. Perforation; 44. Connecting rod; 45. Clamping plate; 46. Insertion hole; 47. Insertion hole; 48. Hoop groove; 49. Insertion port; 50. Modified foamed concrete; 51. Karst cavity. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0024] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are 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, the above terms should not be construed as limiting this invention.

[0025] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0026] like Figures 1-13 The present invention provides a construction method for a toughening system for deep-water, high-scour pile foundations in karst-developed, fractured rock masses, comprising the following steps: Step 1, Cofferdam Construction: A cofferdam is set up around the pile foundation 1 to form a relatively waterless working space, providing working conditions for the construction of steel casing 8, grouting anchor 19 and micro pile 18; Step 2: Inserting grouting anchor rods 19: Based on the distribution of cavities and fissures in the karst-developed fractured rock mass 21, insert the grouting anchor rods 19 into the karst-developed fractured rock mass 21 in a predetermined radial direction, and position the end of the grouting anchor rods 19 corresponding to the fixed sleeve 20 of the annular casting guide groove 17. Step 3: Install steel casing 8: First, assemble and weld the steel casing 8, then put the steel casing 8 on the outside of the bottom of the pile foundation 1, so that the top 36 of the steel casing is located at the predetermined position outside the pile foundation 1, and reserve the structure for connection with the fiberglass sleeve 2 and the annular steel plate bottom plate gabion frame. Step 4: Connect the fixing sleeve 20 to the grouting anchor rod 19: Connect the fixing sleeve 20 to the grouting anchor rod 19 and make the fixing sleeve 20 connected to the annular casting guide channel 17. Establish the grouting channel from the annular casting guide channel 17 to the grouting anchor rod 19 through the grouting hole 42 and the fixing sleeve 20. At the same time, use the pin 40 to fix it through the first insertion hole 46 and the insertion port 49 of the bottom plate 41 of the guide channel. Step 5, construction of micropiles 18: micropiles 18 are arranged around the steel casing 8 so that they are inserted into the karst-developed fractured rock mass 21 around the pile foundation 1 and form circumferentially distributed auxiliary load-bearing components. Step 6: Connecting the micropile 18 to the steel casing 8: First, install the annular fixing plate 14, so that the annular fixing plate 14 and the steel casing 8 are connected by the connecting rod 44. Then, pass the micropile 18 through the micropile insertion hole 38 at the annular fixing plate 14, and use the upper fixing bolt 13 and the lower fixing bolt 15 to fix the micropile 18 on both sides of the annular fixing plate 14, so that the micropile 18 and the steel casing 8 form a cooperative anti-scour structure. Step 7: Injecting cement mortar 16 and filling karst cavities 51: Inject cement mortar 16 into the annular casting guide channel 17, so that the cement mortar 16 enters the grouting anchor 19 through the grouting hole 42, and diffuses and fills the cavities and fissures of the karst-developed fractured rock mass 21, thus completing the grouting reinforcement of the fractured rock mass around the pile foundation 1. At the same time, modified foamed concrete 50 is used to fill and compact the karst cavities 51 around the pile foundation 1. Step 8: Install the annular steel plate bottom gabion frame: After the karst-developed fractured rock mass 21 is reinforced, the annular steel plate bottom gabion frame is fitted onto the outside of the steel casing 8, so that the bottom plate 22 rests on the top of the annular fixing plate 14, and the micropile 18 passes through the micropile insertion hole 38; then the ring 23 is connected to the tension ear plate 27 on the outer periphery of the steel casing 8 by the steel wire cable 10, and the gabion wire mesh 30 is laid around the bottom plate 22 to form a circumferential constraint cavity, and the circumferential constraint cavity is filled with riprap 39; Step 9: Install fiberglass sleeve 2: Place fiberglass sleeve 2 on the outside of pile foundation 1, so that the bottom of fiberglass sleeve 2 rests in the fiberglass sleeve support groove 35 of the top 36 of steel casing. Place the fixing ear plate 5 on the outer periphery of fiberglass sleeve 2 in the fixing ear plate support groove 33 of steel casing 8, and place the clamping plate 45 on the outer periphery of fiberglass sleeve 2 in the clamping plate reserved hole 34 of steel casing 8. Secure it by screws 4 and nuts 7 passing through the fixing ear plate 5. At the same time, fill the space between fiberglass sleeve 2 and pile foundation 1 with underwater epoxy grout 28, and set fixing ring 26 on the outside of fiberglass sleeve 2. Step 10: Remove the cofferdam: After the grouting reinforcement and connection of each protective structure are completed, remove the cofferdam to form a toughened and erosion-resistant system around the pile foundation 1, which consists of fiberglass sleeves 2, steel casings 8, micropiles 18, grouting anchors 19, cement mortar 16, and a ring-shaped steel plate bottom gabion frame.

[0027] This scheme also discloses a toughening system for deep-water high-scour pile foundations in karst-developed rock masses with fractured rock, including a fiberglass sleeve 2 protective structure, a micropile 18 working in conjunction with a steel casing 8 anti-scour structure, a diversion channel working in conjunction with an anchor grouting toughening structure, and an annular steel plate bottom plate gabion frame. The fiberglass sleeve 2 protective structure is used to protect the underwater pile foundation 1. It is set on the side wall of the pile foundation 1 above the steel casing 8 and includes a fiberglass sleeve 2, a fixing ear plate 5, a positioning element 29, and a clamping plate 45. The bottom of the fiberglass sleeve 2 rests in the fiberglass sleeve resting groove 35 of the top 36 of the steel casing. Multiple rows of positioning elements 29 are evenly arranged radially on the inner side wall of the fiberglass sleeve 2. The fixing ear plate 5 and the clamping plate 45 are evenly arranged at the bottom of the fiberglass sleeve 2. The micropiles 18, in conjunction with the steel casing 8, form an anti-scour structure to protect the underwater pile foundation 1. The structure includes a steel casing 8, an annular fixing plate 14, micropiles 18, a vertical clamping plate 31, a fixing ear plate support groove 33, a clamping plate pre-drilled hole 34, a top 36 of the steel casing, connecting ear plates 37, and connecting rods 44. Several micropiles 18 are fixed together by the annular fixing plate 14, upper fixing bolts 13, and lower fixing bolts 15. The inner wall of the annular fixing plate 14 is connected to the outer wall of the steel casing 8 by multiple connecting rods 44. A fiberglass sleeve is provided in the center of the top 36 of the steel casing. The steel casing top 36 is provided with a plurality of fixed ear plate resting grooves 33, a retaining plate reserved hole 34, and a connecting ear plate 37 along the circumferential direction. The fixed ear plate resting grooves 33 are located between two adjacent connecting ear plates 37, and the retaining plate reserved hole 34 is located near the inner side of the steel casing top 36. The steel casing 8 is provided with a plurality of vertical retaining plates 31 evenly along the circumferential direction on the outer side. The vertical retaining plates 31 are provided with through holes 43 evenly on the side. The top of the vertical retaining plates 31 is provided with a tensioning ear plate 27. The vertical retaining plates 31 are located above the plane where the annular fixed plate 14 and the connecting rod 44 are located. The grouting and toughening structure of the diversion channel and anchor bolt is used to toughen and reinforce the fractured rock mass 21 with karst development. It includes an annular cast diversion channel 17, grouting anchor bolts 19, fixing sleeves 20, pins 40, a bottom plate of the diversion channel 41, grouting holes 42, first insertion holes 46, and insertion slots 49. The annular cast diversion channel 17 is welded to the outer side of the bottom of the steel casing 8. A fixing sleeve 20 penetrating the inner wall of the annular cast diversion channel 17 is provided on the outer side of the annular cast diversion channel 17. The top of the inner side of the fixing sleeve 20 is provided with grouting holes 42 and first insertion holes 46. The outer end of the fixing sleeve 20 is connected to the grouting anchor bolts 19. The bottom plate of the diversion channel 41 is located at the bottom of the annular cast diversion channel 17, and the bottom plate of the diversion channel 41 has an insertion slot 49. The insertion slot 49 and the first insertion hole 46 are vertically aligned. The pins 40 pass through the first insertion hole 46 and the insertion slot 49 in sequence for fixation. The annular steel plate base gabion frame is used for riprap protection around the pile foundation 1. It is fitted over the outside of the steel casing 8 and rests on top of the annular fixing plate 14. It includes a central pre-reserved opening 3, a fixing ring 11, columns 12, a base plate 22, ring sleeves 23, vertical ribs 24, gabion wire mesh 30, a vertical arc-shaped ring plate 32, micropile insertion holes 38, and a second insertion hole 47. The fixing ring 11 is connected to the base plate 22 via several columns 12 to form the overall framework of the annular steel plate base gabion frame. Gabion wire mesh 30 is provided between the fixing ring 11, columns 12, and base plate 22. Multiple columns 12 are evenly distributed below the fixing ring 11, and are evenly distributed on the top of the base plate 22. Multiple ring sleeves 23 are evenly distributed circumferentially along the fixing ring 11. The base plate 22 has a central pre-reserved opening 3 in the center. 2. Multiple through-holes 38 for micro-piles are provided at the top. Multiple vertical arc-shaped ring plates 32 are evenly arranged around the central reserved opening 3. A guide positioning slot 6 matching the vertical fixing plate 31 is formed between adjacent vertical arc-shaped ring plates 32. Multiple second insertion holes 47 are provided at the center of the top of the bottom plate 22. The second insertion holes 47 are perpendicularly connected to the guide positioning slot 6. A vertical rib plate 24 is provided at the center of the outer side of the vertical arc-shaped ring plate 32. A hoop opening 9 is provided at the intersection of the vertical rib plate 24 and the vertical arc-shaped ring plate 32. Hoop grooves 48 are evenly arranged on the outer side of the vertical arc-shaped ring plate 32. The hoop grooves 48 and the hoop opening 9 are connected on the same plane. The riprap 39 is located in the annular steel plate bottom plate gabion frame cavity composed of the bottom plate 22, vertical rib plate 24, gabion wire mesh 30, vertical fixing plate 31 and vertical arc-shaped ring plate 32. The bottom of the fiberglass sleeve 2 rests in the fiberglass sleeve support groove 35 at the top of the steel casing 8. The fixing ear plate 5 rests in the fixing ear plate support groove 33. The clamping plate 45 rests in the clamping plate reserved hole 34 between the two docking ear plates 37. The screw 4 passes through the reserved hole of the docking ear plate 37 and the reserved hole of the fixing ear plate 5 in sequence, and is fixed with the nut 7. The positioning member 29 abuts against the outer wall of the pile foundation 1. Underwater epoxy grouting material 28 is provided between the fiberglass sleeve 2 and the outer wall of the pile foundation 1. Multiple fixing rings 26 are provided on the outer side of the fiberglass sleeve 2.

[0028] The steel casing 8 is fitted on the outer wall of the bottom pile foundation 1. The vertical clamping plate 31 is placed in the guide positioning slot 6 and the second insertion hole 47. The annular sleeve 25 passes through the sleeve opening 9 and is clamped in the sleeve groove 48.

[0029] The micropile 18 passes through the corresponding annular fixing plate 14 and micropile insertion hole 38 in sequence, and is fixed with the lower fixing bolt 15 and the upper fixing bolt 13. The base plate 22 rests on the top of the annular fixing plate 14. The ring 23 is fixed to the tie plate 27 by the steel wire cable 10. The gabion wire mesh 30 is hung between the tie range of the steel wire cable 10.

[0030] The annular pouring channel 17 contains cement mortar 16, which enters the grouting anchor 19 through the grouting hole 42 and fills the cavities and gaps between the karst-developed fractured rock mass 21. The karst cavities 51 around the pile foundation 1 are filled with modified foamed concrete 50. The modified foamed concrete 50 is a fiber-reinforced solid waste-based modified foamed concrete, which, by the total mass of cementitious materials, includes the following raw materials: cement 45%-52%; slag powder 22%-30%; basalt powder 14%-20%; bamboo-based biochar 4%-8%. Furthermore, the modified foamed concrete 50 also contains composite fibers, which are composed of basalt fibers and natural plant fibers (coconut shell fibers or sisal fibers). The volume ratio of basalt fibers to natural plant fibers is 1:1.5-1:2.5, and the total fiber volume content is 0.3%-0.6%.

[0031] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A construction method for a toughening system for deep-water, high-scour pile foundations in karst-developed, fractured rock masses, characterized in that... Includes the following steps: Step 1: Construct a cofferdam around the pile foundation (1); Step 2: Insert the grouting anchor (19) into the karst-developed fractured rock mass (21), and position the end of the grouting anchor (19) corresponding to the fixed sleeve (20) of the annular casting guide channel (17); Step 3: Place the steel casing (8) on the outside of the bottom of the pile foundation (1) so that the top (36) of the steel casing is located at the predetermined position outside the pile foundation (1); Step 4: Connect the fixed sleeve (20) to the grouting anchor (19) and connect the fixed sleeve (20) to the annular pouring guide channel (17). Establish the grouting channel from the annular pouring guide channel (17) to the grouting anchor (19) through the grouting hole (42) and the fixed sleeve (20). Step 5: Arrange micropiles (18) around the steel casing (8) so that the micropiles (18) are inserted into the karst-developed fractured rock mass (21) around the pile foundation (1); Step 6: First, install the annular fixing plate (14) so ​​that the annular fixing plate (14) and the steel casing (8) are connected by a connecting rod (44). Then, pass the micro pile (18) through the micro pile insertion hole (38) at the annular fixing plate (14). Step 7: Inject cement mortar (16) into the annular pouring guide channel (17), so that the cement mortar (16) enters the grouting anchor (19) through the grouting hole (42) and diffuses and fills the cavity and fissure of the karst-developed fractured rock mass (21). At the same time, modified foam concrete (50) is used to fill and compact the karst cavity (51) around the pile foundation (1). Step 8: Place the annular steel plate bottom plate gabion frame on the outside of the steel casing (8), so that the bottom plate (22) rests on the top of the annular fixed plate (14), and let the micropile (18) pass through the micropile insertion hole (38); lay gabion wire mesh (30) around the bottom plate (22) to form a circumferential constraint cavity, and fill the circumferential constraint cavity with riprap (39); Step 9: Place the fiberglass sleeve (2) on the outside of the pile foundation (1), so that the bottom of the fiberglass sleeve (2) rests in the fiberglass sleeve resting groove (35) of the top (36) of the steel casing, place the fixing ear plate (5) on the outer periphery of the fiberglass sleeve (2) in the fixing ear plate resting groove (33) of the steel casing (8), place the clamping plate (45) on the outer periphery of the fiberglass sleeve (2) in the clamping plate reserved hole (34) of the steel casing (8), fill the gap between the fiberglass sleeve (2) and the pile foundation (1) with underwater epoxy grouting material (28), and set a fixing ring hoop (26) on the outside of the fiberglass sleeve (2); Step 10: After the grouting reinforcement and connection of all protective structures are completed, dismantle the cofferdam.

2. The construction method of the toughening system for deep-water high-scour pile foundations in karst-developed rock masses as described in claim 1, characterized in that: In step nine, multiple rows of positioning elements (29) are evenly arranged radially on the inner wall of the fiberglass sleeve (2), and the positioning elements (29) abut against the outer wall of the pile foundation (1).

3. The construction method of the toughening system for deep-water high-scour pile foundations in karst-developed rock masses according to claim 1, characterized in that: In step nine, the fixed ear plate support groove (33) is set between two adjacent mating ear plates (37). Several vertical clamping plates (31) are evenly provided on the outer side of the steel casing (8) along the circumference. The vertical clamping plates (31) are evenly provided with perforations (43) on the side. The top of the vertical clamping plates (31) is provided with a tensioning ear plate (27). The vertical clamping plates (31) are located above the plane where the annular fixed plate (14) and the connecting rod (44) are located.

4. The construction method of the toughening system for deep-water high-scour pile foundations in karst-developed rock masses according to claim 1, characterized in that: In step four, a fixed sleeve (20) penetrating the inner wall is provided on the outer side of the annular casting guide channel (17). The top of the inner side of the fixed sleeve (20) is provided with a grouting hole (42) and a first insertion hole (46). The bottom plate (41) of the guide channel is located at the bottom of the annular casting guide channel (17), and the bottom plate (41) of the guide channel is provided with an insertion port (49). The insertion port (49) and the first insertion hole (46) are vertically aligned so that the pin (40) passes through the first insertion hole (46) and the insertion port (49) in sequence for fixation.

5. The construction method of the toughening system for deep-water high-scour pile foundations in karst-developed rock masses according to claim 3, characterized in that: In step eight, the fixing ring (11) is connected to the base plate (22) through several columns (12). A gabion wire mesh (30) is provided between the fixing ring (11), the columns (12) and the base plate (22). Multiple ring sleeves (23) are evenly distributed along the circumference of the fixing ring (11). The base plate (22) has a central reserved opening (3) in the center and multiple through micro pile insertion holes (38) are provided above the top of the base plate (22).

6. The construction method of the toughening system for deep-water high-scour pile foundations in karst-developed rock masses according to claim 5, characterized in that: The central reserved opening (3) is uniformly provided with multiple vertical arc-shaped ring plates (32) along the circumference. A guide positioning slot (6) matching the vertical clamping plate (31) is formed between adjacent vertical arc-shaped ring plates (32). Multiple second insertion holes (47) are provided at the center of the top of the bottom plate (22). The second insertion holes (47) are perpendicularly connected to the guide positioning slot (6). A vertical rib plate (24) is provided at the center of the outer side of the vertical arc-shaped ring plate (32). A sleeve opening (9) is provided at the junction of the vertical rib plate (24) and the vertical arc-shaped ring plate (32). A sleeve groove (48) is uniformly provided on the outer side of the vertical arc-shaped ring plate (32). The sleeve groove (48) and the sleeve opening (9) are connected on the same plane.

7. The construction method of the toughening system for deep-water high-scour pile foundations in karst-developed rock masses as described in claim 6, characterized in that: The vertical clamping plate (31) is placed in the guide positioning slot (6) and the second insertion hole (47), and the annular sleeve (25) passes through the sleeve opening (9) and is then clamped in the sleeve groove (48).

8. The construction method of the toughening system for karst-developed rock mass fractured deep-water high-scour pile foundation according to claim 3, characterized in that: The micropile (18) passes through the corresponding annular fixing plate (14) and micropile insertion hole (38) in sequence, and is fixed with the lower fixing bolt (15) and the upper fixing bolt (13). The base plate (22) rests on the top of the annular fixing plate (14), and the ring sleeve (23) is fixed on the tension ear plate (27) by the steel wire cable (10).

9. The construction method of the toughening system for deep-water high-scour pile foundations in karst-developed rock masses according to claim 1, characterized in that: In step seven, the modified foamed concrete (50) includes 45%-52% cement, 22%-30% slag powder, 14%-20% basalt powder, and 4%-8% bamboo-based biochar; the modified foamed concrete (50) also contains composite fibers, including basalt fiber and natural plant fiber, the volume ratio of basalt fiber to natural plant fiber is 1:1.5-1:2.5, and the total fiber volume content is 0.3%-0.6%.

10. A toughening system for deep-water, high-scour pile foundations in karst-developed, fractured rock masses, characterized in that: The toughening system for karst-developed rock mass fractured deep-water high-scour pile foundations is obtained by construction method according to any one of claims 1-9.

Images