Mud leakage prevention construction method for overlong cast-in-place pile in offshore riprap area

Abstract

The invention relates to the technical field of offshore riprap area super-long cast-in-place piles, and discloses an offshore riprap area super-long cast-in-place pile slurry leakage prevention construction method which comprises the following steps: S1, early-stage preparation work; s2, positioning and drilling are carried out; s3, hole cleaning treatment is carried out; s4, grouting slurry; s5, the pile top elevation of the cast-in-place pile is determined and marked; and S6, performing subsequent treatment. Through the design of the super-long cast-in-place pile, the cast-in-place pile sinks deep underground, the stability and the anti-seismic property of a pile body are improved, and the foundation is protected from being affected by water flow and wave scouring; hole cleaning treatment is conducted after drilling is completed, the hole wall is kept clean, the quality of follow-up grouting slurry is guaranteed, slurry leakage prevention measures are taken during slurry grouting, filler and water flow in the cast-in-place pile are isolated, the slurry leakage phenomenon is reduced, the grouting speed and pressure of the cast-in-place pile are controlled, and it is guaranteed that the grouting slurry is full and tightly solidified.

Description

Technical Field

[0001] The invention relates to the technical field of super-long cast-in-place piles in offshore riprap areas, and in particular to a slurry leakage prevention construction method for super-long cast-in-place piles in offshore riprap areas. Background Art

[0002] Extra-long bored piles refer to bored piles that are longer than ordinary bored piles, and are generally required to be more than 20 meters long. In offshore riprap areas, due to the scouring of seawater and the impact of waves, the foundation is prone to holes, so extra-long bored piles are used to increase the stability and seismic performance of the pile body. The extra-long bored pile method is used to sink the pile body deeper into the ground, and the bored pile anti-leakage slurry technology is used to protect the foundation from the impact of water flow and wave scouring.

[0003] After searching, the patent with application number CN201810426981.4 discloses a method for constructing bored piles in fractured geology, including the following steps: 1) preparing a slag barrel; 2) preparing a reinforced cage for bored piles; 3) drawing holes for bored piles; 4) extracting hole slag with a slag barrel; 5) removing hole slag with a slag barrel; 6) lowering the reinforced cage for bored piles; 7) squeezing and widening a leak-proof slurry bag; 8) pouring concrete; and 9) grouting outside the leak-proof slurry bag. The beneficial effects of the invention are as follows: a bottom cutting blade and a water guide pipe are arranged at the bottom of the slag removal barrel, which can greatly reduce the difficulty of extracting slag from the crack area and improve the on-site construction efficiency; an auxiliary slag flushing pipe is arranged inside the slag removal barrel to help improve the slag discharge effect of the slag removal barrel; the grout sealing end plate is arranged to avoid the slag removal barrel from being raised, effectively enhance the connection strength of the structure, realize the coordinated force of building materials with different properties, and improve the integrity of the structure; a leak-proof slurry bag is arranged at the crack position, and a crack reinforcement body is arranged on the outside of the bag, which can not only prevent the outflow of the injected cement slurry, but also save building materials.

[0004] The bored piles prepared by the current anti-leakage grouting construction method are shorter and less stable, which reduces the stability and seismic performance of the pile body. The bored piles are easily affected by water flow and wave scouring; and the treatment effect on the borehole is not good. After grouting, the filling material in the bored pile cannot be effectively isolated from the water flow, and leakage is prone to occur. Therefore, we need to propose a anti-leakage grouting construction method for super-long bored piles in offshore riprap areas. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preventing leakage of super-long bored piles in offshore riprap areas. Through the design of super-long bored piles, the bored piles are sunk deep underground, which increases the stability and seismic resistance of the pile body and protects the foundation from being affected by water flow and wave scouring. After the drilling is completed, the hole is cleaned to keep the hole wall clean and ensure the quality of the subsequent grouting. When grouting, anti-leakage measures are taken to isolate the filler in the bored pile from the water flow, reduce leakage, and control the grouting speed and pressure of the bored pile to ensure that the grouting grout is substantial and tightly solidified, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preventing leakage of super-long cast-in-place piles in offshore riprap areas, comprising the following steps: S1. Preliminary preparations: Build a stable construction platform in the offshore riprap area and prepare the machinery and equipment required for construction; S2. Positioning and drilling: select demonstration piles for positioning as a reference for subsequent construction, determine the specific location and spacing of the super-long cast-in-place piles, and finally use a drilling rig to carry out the drilling construction of the super-long cast-in-place piles; S3, hole cleaning: After the drilling is completed, clean the sand and gravel inside the borehole to keep the hole wall clean; S4. Grouting: Use pumping technology to inject premixed grout into the bored hole of the bored pile, and take anti-leakage measures to isolate the filling material in the bored pile from the water flow to reduce leakage; S5. Determine the top elevation of the bored pile and mark it; S6. Subsequent processing: After the injected slurry solidifies, pile top treatment and quality inspection are carried out.

[0007] Preferably, in step S2, positioning and drilling include positioning demonstration piles, pile position positioning, and drilling construction, wherein the process of positioning demonstration piles is on-site investigation and design, demonstration pile selection and installation, and verification and adjustment of installed demonstration piles; the process of pile position positioning is: clarifying the installation parameters of extra-long cast-in-place piles, on-site measurement and marking the positions of cast-in-place piles, and verifying and adjusting the marked cast-in-place pile positions; the process of drilling construction is: selecting and debugging the drilling rig, setting drilling parameters, controlling and monitoring the drilling process, taking protective measures to protect the hole wall from collapse, and drilling acceptance.

[0008] Preferably, in step S3, the process of cleaning the borehole is as follows: S31. Select a high-pressure water washer or air compressor as the hole cleaning equipment according to the diameter and depth of the drill hole; S32. Before cleaning the hole, check whether there are large pieces of gravel or obstacles inside the hole; S33, connecting the hole cleaning device to the borehole opening, adjusting the pressure and flow rate of the cleaning fluid according to the diameter and depth of the borehole, and keeping the nozzle moving stably in the borehole; S34. During the hole cleaning process, closely monitor the color and turbidity of the cleaning fluid to judge the cleanliness inside the drill hole.

[0009] Preferably, in step S4, the process of grout perfusion is as follows: S41. According to the grout formula, make the grout proportion and pre-stir the grout using a stirring device to ensure that the grout is uniform and has stable performance; S42. According to the depth and diameter of the drill hole, select a pumping device and debug it; S43. Pump the grout into the drill hole. During the process of grout perfusion, control the injection speed and pressure of the injected grout; S44. Closely monitor the grouting process, observe the changes in the grouting volume and grouting pressure, and adjust the grouting parameters or check the grouting equipment in a timely manner according to the situation.

[0010] Preferably, in step S4, the anti-leakage measures are as follows: During the drill hole process or before grouting, according to the diameter and depth of the drill hole, insert the bottom of a steel casing with appropriate length and strong stiffness into the stable layer or rock layer to resist the risks of borehole wall collapse and leakage.

[0011] Preferably, in step S5, clarify the top design elevation of the extra-long cast-in-place pile, and use a total station or a level to measure the elevation of the construction site. According to the measurement results, determine whether there is a deviation between the actual top elevation and the design elevation of each cast-in-place pile; if there is an elevation deviation, adjust the elevation in a timely manner and make a mark.

[0012] Preferably, the pumping device includes a grouting pipe for inserting into the drill hole, a feeding pipe for conveying the grout to the grouting pipe, and a lifting mechanism for driving the grouting pipe to lift and lower.

[0013] Preferably, the feeding pipe includes a connecting pipe, a flow valve is installed on the connecting pipe, one end of the connecting pipe is connected with a grout delivery hose, the top of the grouting pipe is connected with a grouting funnel, and the grout delivery hose is connected with the grouting funnel.

[0014] Preferably, the lifting mechanism includes a first lifting plate, a second lifting plate, and a third lifting plate arranged in a U shape. A first electric sliding table is installed on the inner side wall of the first lifting plate, and the sliding seat of the first electric sliding table is connected to the outer wall of the second lifting plate. A second electric sliding table is installed on the inner side wall of the second lifting plate, and the sliding seat of the second electric sliding table is connected to the outer wall of the third lifting plate.

[0015] Preferably, a fixing block is installed at the upper end of the inner wall of the third lifting plate, a chain is connected to the bottom of the fixing block, two ear seats are installed on the side of the grouting funnel, and the bottom of the chain is connected to the ear seats.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses the design of super-long bored piles to sink the bored piles deep underground, thereby increasing the stability and earthquake resistance of the pile body and protecting the foundation from the impact of water flow and wave scouring; 2. The present invention performs hole cleaning after drilling is completed to keep the hole wall clean and ensure the quality of subsequent grouting slurry. During grouting, anti-leakage measures are taken to isolate the filler in the bored pile from the water flow, reduce leakage, and control the grouting speed and pressure of the bored pile to ensure that the grouting slurry is substantial and tightly solidified. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flowchart of the present invention; Figure 2 It is a schematic structural diagram of the pumping equipment of the present invention.

[0018] In the figure: 1. Lifting plate one; 2. Lifting plate two; 3. Lifting plate three; 4. Fixed block; 5. Chain; 6. First electric slide; 7. Second electric slide; 8. Connecting pipe; 9. Flow valve; 10. Slurry delivery hose; 11. Grouting pipeline; 12. Grouting funnel; 13. Ear seat. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1-2 The present invention provides a technical solution: a method for preventing leakage of super-long cast-in-place piles in offshore riprap areas, comprising the following steps: S1. Preliminary preparations: Build a stable construction platform in the offshore riprap area and prepare the machinery and equipment required for construction; According to the project requirements and geological conditions, select the appropriate construction platform location. The structure of the construction platform is designed to ensure that it can bear the weight of construction equipment and personnel, and resist seawater scouring and wave impact.

[0021] After the platform is built, conduct a comprehensive safety inspection to ensure there are no potential safety hazards, and regularly maintain and service the construction platform to extend its service life.

[0022] Machinery and equipment include drilling rigs (or vibratory drills), high-pressure water washers, pumping machines, concrete mixing stations and other equipment. The equipment must be installed and debugged before construction, and construction personnel must be trained on equipment operation to ensure that they can operate the equipment proficiently.

[0023] S2. Positioning and drilling: select demonstration piles for positioning as a reference for subsequent construction, determine the specific location and spacing of the super-long cast-in-place piles, and finally use a drilling rig to carry out the drilling construction of the super-long cast-in-place piles; In step S2, positioning and drilling include positioning demonstration piles, pile location positioning, and drilling construction; Among them, the process of locating demonstration piles includes on-site investigation and design, selection and installation of demonstration piles, and verification and adjustment of installed demonstration piles; The process of pile positioning is: clarify the installation parameters of extra-long bored piles, measure and mark the positions of bored piles on site, and verify and adjust the marked positions of bored piles; the installation parameters of extra-long bored piles include the specific number, position, spacing and direction of extra-long bored piles.

[0024] The process of drilling construction is: selecting and debugging the drilling rig, setting drilling parameters, controlling and monitoring the drilling process, taking protective measures to prevent the hole wall from collapsing, and drilling acceptance.

[0025] S3, hole cleaning: After the drilling is completed, clean the sand and gravel inside the borehole to keep the hole wall clean; In step S3, the process of cleaning the borehole is as follows: S31. Select a high-pressure water washer or air compressor as the hole cleaning equipment according to the diameter and depth of the drill hole; S32. Before cleaning the hole, check whether there are large pieces of gravel or obstacles inside the borehole; check whether the connecting pipes and nozzles of the hole cleaning equipment are unobstructed to ensure that the cleaning fluid can be sprayed out smoothly.

[0026] S33, connecting the hole cleaning device to the borehole opening, adjusting the pressure and flow rate of the cleaning fluid according to the diameter and depth of the borehole, and keeping the nozzle moving stably in the borehole to avoid damage to the hole wall; S34. During the hole cleaning process, closely monitor the color and turbidity of the cleaning fluid to determine the cleanliness of the inside of the borehole.

[0027] During the hole cleaning process, pay attention to protecting the hole wall to prevent the cleaning fluid from scouring or corroding the hole wall. If chemical cleaning agents are required, ensure that the cleaning agents have no corrosive effect on the hole wall material. After the hole is cleaned, use detection tools (such as endoscopes, cameras, etc.) to inspect the inside of the borehole to confirm that there is no residual sand and gravel on the hole wall.

[0028] S4. Grouting: Use pumping technology to inject premixed grout into the bored hole of the bored pile, and take anti-leakage measures to isolate the filling material in the bored pile from the water flow to reduce leakage; In step S4, the process of pouring grout is as follows: S41. Mix the slurry according to the slurry formula and use a stirring device to pre-stir the slurry to ensure uniform mixing and stable performance; S42. Select and debug the pumping equipment according to the depth and diameter of the borehole; S43, pumping the slurry into the borehole, and controlling the speed and pressure of injecting the slurry during the process of injecting the slurry; S44. Closely monitor the grouting process, observe the changes in grouting volume and grouting pressure, and adjust grouting parameters or check grouting equipment in time according to the situation.

[0029] In step S4, the slurry leakage prevention measures are as follows: During the drilling process or before grouting, the bottom of a steel casing of suitable length and strong rigidity is inserted into a stable layer or rock layer according to the diameter and depth of the borehole to resist the risk of hole wall collapse and grout leakage.

[0030] As the anti-leakage slurry material for cast-in-place piles, select slurry materials with high strength, good water resistance and strong anti-seepage performance to ensure that the slurry materials can form a dense waterproof layer and effectively isolate the filling materials in the pile from the water flow; When constructing in the offshore riprap area, it is necessary to pay close attention to water level changes. By setting up small mud pools, large mud pools, filter screens and other devices, the mud liquid level in the hole can be lowered to reduce the water head difference inside and outside the casing. The water level difference inside and outside the casing should be checked regularly. If the water level difference is found to be too large, timely measures should be taken to adjust it.

[0031] After the grouting is completed, the grouting holes are sealed and the leakage prevention effect is checked. If leakage is found, timely remedial measures must be taken to ensure the bearing capacity of the pile and the construction quality.

[0032] S5. Determine the top elevation of the bored pile and mark it; In step S5, the design elevation of the top of the super-long bored pile is determined, and the elevation of the construction site is measured using a total station or a level. Based on the measurement results, it is determined whether there is a deviation between the actual top elevation of each bored pile and the design elevation; if there is a deviation in the elevation, the elevation is adjusted in time and marked.

[0033] S6. Subsequent processing: After the injected slurry solidifies, pile top treatment and quality inspection are carried out.

[0034] After the grouting material is completely cured, subsequent treatment can be carried out. Trim the pile top to ensure it is flat, without cracks and defects. If pile top heightening or shortening treatment is required, operate strictly in accordance with the design requirements. Conduct pile integrity testing, such as low-strain testing, ultrasonic testing, etc., to ensure there are no cracks, cavities and other defects in the pile body. Conduct bearing capacity testing, such as static load test, dynamic load test, etc., to ensure that the pile body meets the design requirements.

[0035] The pumping equipment includes a grouting pipeline 11 for inserting into the drill hole, a feeding pipe for conveying the slurry to the grouting pipeline 11, and a lifting mechanism for driving the grouting pipeline 11 to lift and lower. The lifting mechanism is installed on an engineering vehicle (not shown in the figure) for use.

[0036] The feeding pipe includes a connecting pipe 8, on which a flow valve 9 is installed. The flow valve 9 is used to adjust the flow rate, speed and pressure of grouting. One end of the connecting pipe 8 is connected with a slurry feeding hose 10, and the top of the grouting pipeline 11 is connected with a grouting funnel 12. The slurry feeding hose 10 is connected with the grouting funnel 12, and the slurry can be pumped into the grouting pipeline 11 through the feeding pipe.

[0037] The lifting mechanism includes a lifting plate one 1, a lifting plate two 2, and a lifting plate three 3 arranged in a U shape. The inner side wall of the lifting plate one 1 is installed with a first electric sliding table 6, and the sliding seat of the first electric sliding table 6 is connected to the outer wall of the lifting plate two 2. The inner side wall of the lifting plate two 2 is installed with a second electric sliding table 7, and the sliding seat of the second electric sliding table 7 is connected to the outer wall of the lifting plate three 3.

[0038] When lifting the grouting pipeline 11, the first electric sliding table 6 drives the lifting plate two 2 to move upward, the second electric sliding table 7 drives the lifting plate three 3 to move upward, and the lifting plate three 3 drives the grouting pipeline 11 to move upward.

[0039] At the upper end of the inner wall of the lifting plate three 3, a fixing block 4 is installed. The bottom of the fixing block 4 is connected with a chain 5. Two ear seats 13 are installed on the side of the grouting funnel 12, and the bottom of the chain 5 is connected to the ear seats 13.

[0040] When the pumping equipment is in use, when the engineering vehicle drives the pumping equipment to move near the drill hole, assemble a grouting pipeline 11 with a suitable size according to the drill hole depth and diameter, and install the grouting pipeline 11 on the lifting mechanism through the connection between the chain 5 and the ear seat 13, and then connect the feeding pipe to the grouting funnel 12; Then put the grouting pipeline 11 into the drill hole, and the bottom of the grouting pipeline 11 does not touch the bottom of the drill hole (the distance is 30 - 80 cm). Let the slurry flow into the grouting pipeline 11 through the feeding pipe to start grouting. The liquid level height of the slurry in the drill hole gradually rises, and after grouting to a certain height, drag the grouting pipeline 11 to rise through the lifting mechanism (lift the grouting pipeline 11 while grouting).

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preventing leakage of super-long cast-in-place piles in offshore riprap areas, characterized in that: The following steps are involved: S1. Preliminary preparations: Build a stable construction platform in the offshore riprap area and prepare the machinery and equipment required for construction; S2. Positioning and drilling: select demonstration piles for positioning as a reference for subsequent construction, determine the specific location and spacing of the super-long cast-in-place piles, and finally use a drilling rig to carry out the drilling construction of the super-long cast-in-place piles; S3, hole cleaning: After the drilling is completed, clean the sand and gravel inside the borehole to keep the hole wall clean; S4. Grouting: Use pumping technology to inject premixed grout into the bored hole of the bored pile, and take anti-leakage measures to isolate the filling material in the bored pile from the water flow to reduce leakage; S5. Determine the top elevation of the bored pile and mark it; S6. Subsequent processing: After the injected slurry solidifies, pile top treatment and quality inspection are carried out.

2. The method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 1 is characterized by: In step S2, positioning and drilling include positioning demonstration piles, pile position positioning, and drilling construction, wherein the process of positioning demonstration piles is on-site investigation and design, demonstration pile selection and installation, and verification and adjustment of installed demonstration piles; the process of pile position positioning is: clarifying the installation parameters of extra-long cast-in-place piles, on-site measurement and marking the positions of cast-in-place piles, and verifying and adjusting the marked cast-in-place pile positions; the process of drilling construction is: selecting and debugging the drilling rig, setting drilling parameters, controlling and monitoring the drilling process, taking protective measures to protect the hole wall from collapse, and drilling acceptance.

3. The method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 1 is characterized in that: In step S3, the process of cleaning the borehole is as follows: S31. Select a high-pressure water washer or air compressor as the hole cleaning equipment according to the diameter and depth of the drill hole; S32. Before cleaning the hole, check whether there are large pieces of gravel or obstacles inside the hole; S33, connecting the hole cleaning device to the borehole opening, adjusting the pressure and flow rate of the cleaning fluid according to the diameter and depth of the borehole, and keeping the nozzle moving stably in the borehole; S34. During the hole cleaning process, closely monitor the color and turbidity of the cleaning fluid to determine the cleanliness of the inside of the borehole.

4. The method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 1 is characterized by: In step S4, the process of pouring grout is as follows: S41. Mix the slurry according to the slurry formula and use a stirring device to pre-stir the slurry to ensure uniform mixing and stable performance; S42. Select and debug the pumping equipment according to the depth and diameter of the borehole; S43, pumping the slurry into the borehole, and controlling the speed and pressure of injecting the slurry during the process of injecting the slurry; S44. Closely monitor the grouting process, observe the changes in grouting volume and grouting pressure, and adjust grouting parameters or check grouting equipment in time according to the situation.

5. The method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 1 is characterized by: In step S4, the slurry leakage prevention measures are as follows: During the drilling process or before grouting, the bottom of a steel casing of suitable length and strong rigidity is inserted into a stable layer or rock layer according to the diameter and depth of the borehole to resist the risk of hole wall collapse and grout leakage.

6. The method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 1 is characterized by: In step S5, the design elevation of the top of the super-long cast-in-place pile is determined, and the elevation of the construction site is measured using a total station or a level, and based on the measurement results, it is determined whether there is a deviation between the actual top elevation of each cast-in-place pile and the design elevation; If there is any deviation in the elevation, adjust the elevation in time and mark it.

7. The method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 4 is characterized by: The pumping equipment includes a grouting pipeline (11) for inserting into the interior of a borehole, a feed pipe for conveying grout to the grouting pipeline (11), and a lifting mechanism for driving the grouting pipeline (11) to lift and lower.

8. The method for preventing leakage of super-long bored piles in offshore riprap areas according to claim 7 is characterized by: The feed pipe includes a connecting pipe (8), a flow valve (9) is installed on the connecting pipe (8), one end of the connecting pipe (8) is connected with a grout delivery hose (10), the top of the grouting pipeline (11) is connected with a grouting funnel (12), and the grout delivery hose (10) is connected with the grouting funnel (12).

9. A method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 8, characterized in that: The lifting mechanism includes a first lifting plate (1), a second lifting plate (2), and a third lifting plate (3) arranged in a U shape. A first electric slide table (6) is installed on the inner side wall of the first lifting plate (1), and the slide seat of the first electric slide table (6) is connected to the outer wall of the second lifting plate (2). A second electric slide table (7) is installed on the inner side wall of the second lifting plate (2), and the slide seat of the second electric slide table (7) is connected to the outer wall of the third lifting plate (3).

10. A method for preventing leakage of super-long cast-in-place piles in offshore riprap areas according to claim 9, characterized in that: A fixing block (4) is installed at the upper end of the inner wall of the third lifting plate (3), a chain (5) is connected to the bottom of the fixing block (4), two ear seats (13) are installed on the side of the grouting funnel (12), and the bottom of the chain (5) is connected to the ear seats (13).

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