Construction method of high-pressure jet grouting pile anchoring solidified soil-riprap combined scouring prevention and control structure

Abstract

The invention discloses a construction method of a high-pressure jet grouting pile anchoring solidified soil-riprap combined scouring prevention and control structure. The structure is composed of a high-pressure jet grouting pile and a solidified soil-riprap prevention and control body from bottom to top, and natural attachment of a pile body, riprap and a scour pit seabed is achieved through solidified soil; during construction, through scanning positioning, single-pipe high-pressure jet grouting is adopted to pump solidified soil slurry to a certain depth of the bottom of a scour pit at specific positions in front of a scour pit pile and on the pile side, and an anchoring pile body is reserved; and filling the scour pit with solidified soil slurry to a certain height, then filling riprap until solidified soil overflows, and carrying out self-leveling. After the solidified soil is cemented and formed, a solidified soil-riprap prevention and control body anchored by the solidified soil high-pressure jet grouting pile is formed in the scouring pit; structural integration is achieved through the solidified soil, the anchoring effect is exerted in combination with the high-pressure jet grouting piles, the risks of riprap secondary scouring and solidified soil edge undercutting are effectively reduced, and the construction cost of the full-pouring solidified soil is reduced.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering prevention and control technology and new energy, and relates to a construction method for a high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure; specifically, it relates to a construction method for a high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure for scour control of offshore wind power foundations, bridge piers and other structures. Background Technology

[0002] In marine environments, offshore wind turbine foundations are susceptible to localized erosion under the long-term effects of water currents, waves, and tides, threatening structural safety. Currently, commonly used erosion control measures include riprap, soil stabilization, and sand covering. Among these, simple riprap protection has limited erosion resistance and is prone to secondary erosion; while full-area soil stabilization is costly and its edges are easily eroded, affecting the overall protection effect and weakening the bearing capacity of the foundation.

[0003] To improve protective performance, current offshore wind power foundation scour control is increasingly adopting composite technologies. (Chinese Patent CN202322970308.6 discloses a protective structure for scour pits in offshore monopile foundations). This structure is located within the scour pit and combines multi-graded crushed stone with solidified soil filling its pores. After hardening, it forms a plate-like integral protective body, the top of which is lower than the surrounding original seabed surface, constituting a rigid protective layer. However, existing solidified soil-rubble composite control technologies still have several problems: the rubble is often naturally continuously graded, and the particle size and gradation are not specifically designed, resulting in excessively small pores between the stones, making it difficult for the solidified soil to fully penetrate and mix; the edges of the formed rigid protective body are still prone to erosion, and seabed cracks may extend along the original scour pit boundary towards the pile foundation, affecting overall stability and adversely impacting the pile foundation's bearing capacity. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure that can effectively reduce the risk of secondary scour by riprap and edge erosion of solidified soil, and reduce the construction cost of fully cast solidified soil. Another purpose of this invention is to provide a construction method for the control structure.

[0005] Technical solution: The high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure of the present invention includes large-particle-size uniformly graded rock, solidified soil and pile foundation, wherein the large-particle-size uniformly graded rock and solidified soil are filled together in the scour pit where the pile foundation is located. The solidified soil is solidified into high-pressure jet grouting piles and embedded in the scour pit at a depth below the bottom of a specific location on the pile side.

[0006] Furthermore, the high-pressure jet grouting pile is a fully cast-in-place solidified soil pile with a pile diameter of 0.06D and a pile length of 0.8H below the scour pit; where D is the diameter of the pile foundation and H is the depth of the scour pit.

[0007] Furthermore, the high-pressure jet grouting piles are constructed at four locations: 1D and 2D distances from the pile foundation in the positive direction of the pile side; There are two locations: one at a distance of 1D from the pile foundation in the positive direction, and one at the front and one at the rear of the pile.

[0008] Furthermore, the volume ratio of the solidified soil is: 36% soil, 14% solidifying agent, and 50% seawater.

[0009] Furthermore, the thickness of the slurry layer in the solidified soil is 0.8H, and its volume is approximately 0.5V, where V is the total volume of the scour pit.

[0010] Furthermore, by filling the slurry layer of the solidified soil with riprap, the solidified soil slurry overflows and scours the pit, self-levels, and occupies all the pores between the riprap, thus forming a solidified soil-riprap joint control system.

[0011] Furthermore, the solidified soil-rock control body is in the shape of an inverted cone, and its bottom is bonded to the top of the high-pressure jet grouting pile through solidified soil to form an integrated control structure, and the lower end of the high-pressure jet grouting pile is embedded in the seabed to achieve anchoring.

[0012] Furthermore, the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure has a supported tripod shape.

[0013] Furthermore, the large-particle-size uniformly graded pebbles form a pebbly body, wherein the pebbles have a particle size range of 500mm-700mm and an internal porosity of 40%-50%.

[0014] Furthermore, the construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure includes the following steps: Step (1) The location, extent, and depth of the scour pit in the pile foundation are determined by scanning. Step (2) At four specific locations on the positive side of the pile in the scour pit, solidified soil slurry is pumped to the bottom of the scour pit using a single-pipe high-pressure jet grouting pump. Step (3) At two specific locations in the positive direction before and after the pile in the scour pit, solidified soil slurry is pumped to a certain depth below the bottom of the scour pit using a single-pipe high-pressure jet grouting pump. Step (4) Fill the scour pit with a layer of solidified soil slurry; Step (5) Fill the scour pit with riprap until the solidified soil slurry completely covers the riprap and is level with the seabed.

[0015] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: 1. Based on the anchoring effect of high-pressure jet grouting piles, solidified soil bonding, and riprap stabilization, the overall integrity of the scour control structure is significantly enhanced; the high-pressure jet grouting piles provide under-bearing anchoring, effectively limiting the displacement of riprap under strong hydrodynamic forces, ensuring the stability of the protective structure under edge erosion conditions, and avoiding a significant reduction in the bearing capacity of the pile foundation; after the solidified soil slurry hardens, it effectively bonds the riprap, pile foundation, and seabed, forming a continuous integral structure, improving stability and deformation resistance, and avoiding the problems of delamination, voids, or loosening of traditional riprap layers; the solidified soil fills the pores of the riprap, blocking fluid turbulence and scour paths, significantly improving the overall scour resistance and reducing the risk of secondary scour; 2. By providing deep anchoring force through high-pressure jet grouting piles and using solidified soil as a bonding medium, the high-pressure jet grouting piles and the solidified soil-riprap protection body are integrated. It naturally integrates with the wind turbine pile foundation and seabed, constructing a composite control structure with high integrity and strong erosion resistance, effectively reducing the risk of secondary erosion of the riprap and edge erosion of the solidified soil, and lowering the construction cost of fully cast-in-place solidified soil; 3. The use of large-diameter, uniformly graded riprap, with its near-single-diameter characteristics, gives the riprap accumulation a large porosity, allowing the solidified soil to seep along the pores and fully cement the riprap; 4. Sufficient solidified soil slurry is pre-filled, followed by riprap filling. The riprap occupies space, causing the solidified soil slurry layer to rise and overflow onto the seabed surface. After the surface solidified soil self-levels, it automatically seals the top of the erosion pit, effectively reducing water erosion; 5. Compared to fully cast-in-place solidified soil, this invention can form a stable control body by implementing limited grouting on the pile side, in front of the pile, and in the riprap layer, significantly reducing material usage and construction costs, and has higher economic efficiency and operability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the pile side in the completed construction state of the present invention; Figure 2 This is a schematic diagram of the completed construction state of the present invention before pile laying; Figure 3 This is a top view of the completed construction state of the present invention; In the diagram, 1 is the pile foundation, 2 is large-diameter uniformly graded riprap, 3 is solidified soil, and 4 is a high-pressure jet grouting pile. Detailed Implementation

[0017] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0018] like Figure 1As shown, the construction method of the high-pressure jet grouting pile anchored solidified soil-rock composite scour control structure of the present invention provides deep anchoring force through high-pressure jet grouting pile 4, and uses solidified soil 3 as a cementing medium to realize the integration of high-pressure jet grouting pile 4 and solidified soil-rock protection body, and naturally fits with wind turbine pile foundation and seabed, to construct a composite control structure with high integrity and strong scour resistance; the scour control structure includes a solidified soil-rock composite control body, which is formed by cementing large-particle-size uniformly graded rock 2 and solidified soil 3, and fills the approximately inverted conical scour pit where the pile foundation 1 is located; The high-pressure jet grouting pile 4 is formed by fully casting and hardening (condensing) solidified soil 3. Its top end is self-consistent and integrated with the solidified soil-rock combined prevention and control body, and its bottom end is embedded at a certain depth below six specific positions in front of the scour pit pile and on the side of the pile to play an anchoring role. The high-pressure jet grouting pile 4 and the solidified soil-rock control body are bonded together by the solidified soil 3 to form an integrated control structure, which is a tripod structure with support and can fully and naturally fit with the seabed.

[0019] The construction method of the present invention includes the following steps, wherein the position of the high-pressure jet grouting pile 4 is as follows: Figure 3 As shown: S1. Locate the position, extent, and depth of the scour pit in the pile body by scanning and measuring. S2. At four specific locations on the positive side of the scour pit pile, solidified soil grout is pumped to a certain depth below the bottom of the scour pit using a single-pipe high-pressure jet grouting pump. S3. At two specific locations in the positive direction before and after the pile in the scour pit, solidified soil grout is pumped through a single-pipe high-pressure jet grouting pump to a certain depth below the bottom of the scour pit. S4. Fill the scour pit with a sufficiently thick layer of solidified soil grout 3. S5. Fill the scour pit with large-diameter, uniformly graded riprap 2 until the solidified soil slurry completely covers the riprap and overflows the seabed surface.

[0020] When construction is completed, the solidified soil 3 in the space of the high-pressure jet grouting pile 4 and the solidified soil 3 in the scour pit are hardened and formed at the same time. The overall high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure is a tripod structure with support. The upper solidified soil-rock control body is approximately inverted cone-shaped, and the lower high-pressure jet grouting pile 4 is embedded in the seabed.

[0021] Construction should be equipped with a soil-stabilizing mixing station, a high-pressure jet grouting single-pipe injection pipe, and a rock-dropping pipe, as well as a positioning vessel. The positioning vessel should be equipped with a multibeam echo sounder, an underwater monitoring system, or an ROV robot. The positioning vessel should locate the scour pit and delineate the grouting position of the high-pressure jet grouting piles by multibeam echo sounding. During the pumping of solidified soil and rock dumping by the construction vessel, the positioning vessel should use underwater monitoring equipment or an ROV robot to monitor and record images of the construction site, so that the back-end staff can understand the filling process in real time and adjust the construction details in a timely manner.

[0022] The preferred construction parameters include: high-pressure jet grouting pile 4, which is a fully cast-in-place solidified soil pile with a pile diameter of 0.06D and a pile length of 0.8H below the scour pit; where D is the diameter of pile 1 and H is the depth of the scour pit; The construction location of high-pressure jet grouting pile 4 is as follows Figure 2 As shown: four locations at a distance of 1D and 2D from the pile foundation in the positive direction of the pile side, and two locations at a distance of 1D from the pile foundation in the positive direction in front of and behind the pile; The thickness of the slurry layer of the solidified soil 3 is 0.8H, and its volume is approximately 0.5V; where V is the total volume of the scour pit. By filling the grout layer of solidified soil 3 with large-particle-size uniformly graded riprap 2, the grout of solidified soil 3 overflows from the scouring pit, self-levels, and occupies all the pores between the riprap, forming an approximately inverted cone-shaped solidified soil-riprap joint control body. Its bottom and the top of the high-pressure jet grouting pile 4 are integrated through the solidified soil 3, and the low end of the high-pressure jet grouting pile 4 is embedded in the seabed to achieve anchoring. The high-pressure jet grouting pile 4 anchored solidified soil-rock combined scour control structure is a tripod structure with support. The mix proportion (volume ratio) of solidified soil 3 is: 36% soil, 14% solidifying agent, and 50% seawater; the soil is seabed silt; and the solidifying agent is KZJ L series powdery solidifying agent.

[0023] In construction materials, the requirements for riprap (large-diameter uniformly graded riprap 2) include: having large-diameter and uniformly graded characteristics, with a particle size range of 500mm-700mm, not falling into the space of the high-pressure jet grouting pile 4 or forming an arch at the high-pressure jet grouting pile opening; and having an internal porosity of 40%-50%.

[0024] The requirements for solidified soil 3 include: the retention rate of solidified soil slurry is not less than 85% when the water flow velocity is 2.25 m / s; the strength of solidified soil 3 after solidification is able to withstand long-term wave loads; the undrained shear strength at 28 days is greater than 300 kPa; and it can meet the working conditions of most marine areas.

Claims

1. A high-pressure jet grouting pile anchored solidified soil-rock composite scour control structure, characterized in that, The structure includes large-diameter uniformly graded riprap (2), solidified soil (3) and pile foundation (1), wherein the large-diameter uniformly graded riprap (2) and solidified soil (3) are filled together in the scour pit where the pile foundation (1) is located. The solidified soil (3) solidifies into a high-pressure jet grouting pile (4) and is embedded to a depth below the bottom of a specific position on the front and side of the scour pit pile.

2. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 1, characterized in that, The high-pressure jet grouting pile (4) is a fully cast-in-place solidified soil pile with a pile diameter of 0.06D and a pile length of 0.8H below the scour pit; where D is the diameter of the pile foundation (1) and H is the depth of the scour pit.

3. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 1, characterized in that, The construction positions of the high-pressure jet grouting pile (4) are: 1D and 2D distances from the pile foundation (1) in the positive direction of the pile side, for a total of four positions; There are two locations: one in front of the pile and one behind the pile, at a distance of 1D from the pile foundation (1).

4. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 1, characterized in that, The volume ratio of the solidified soil (3) is: 36% soil, 14% solidifying agent, and 50% seawater.

5. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 1, characterized in that, The thickness of the slurry layer in the solidified soil (3) is 0.8H, and its volume is approximately 0.5V, where V is the total volume of the scour pit.

6. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 5, characterized in that, By filling the slurry layer of the solidified soil (3) with large-particle-uniformly graded pebbles (2), the solidified soil slurry overflows and scours the pit, self-levels, and occupies all the pores between the pebbles, thus forming a solidified soil-pebbles joint control system.

7. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 6, characterized in that, The solidified soil-rock control body is in the shape of an inverted cone. Its bottom and the top of the high-pressure jet grouting pile (4) are bonded together by solidified soil (3) to form an integrated control structure. The bottom of the high-pressure jet grouting pile (4) is embedded in the seabed to achieve anchoring.

8. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 7, characterized in that, The high-pressure jet grouting pile (4) anchors and solidifies the soil-rock combined scour control structure, which is a tripod-shaped structure with support.

9. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure according to claim 1, characterized in that, The large-particle-size uniformly graded pebbles (2) form a pebbles body, wherein the pebbles have a particle size range of 500mm-700mm and the internal porosity of the pebbles body is 40%-50%.

10. The construction method of the high-pressure jet grouting pile anchored solidified soil-rock combined scour control structure as described in any one of claims 1-9, characterized in that, Includes the following steps: Step (1) The location, extent, and depth of the scour pit in the pile foundation (1) are determined by scanning. Step (2) At four specific locations on the positive side of the pile in the scour pit, solidified soil (3) grout is pumped to the bottom of the scour pit using a single-pipe high-pressure jet grouting pump. Step (3) At two specific locations in the positive direction before and after the pile in the scour pit, solidified soil (3) slurry is pumped through a single-pipe high-pressure jet grouting pump to a certain depth below the bottom of the scour pit. Step (4) Fill the scour pit with a layer of solidified soil slurry; Step (5) Fill the scour pit with riprap until the solidified soil slurry completely covers the riprap and is level with the seabed.

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