A drag-reducing isolation structure applied to a precast pile and a construction method thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING ZHONGYAN DADI TECH CO LTD
- Filing Date
- 2024-01-03
- Publication Date
- 2026-06-26
AI Technical Summary
In soft soil and fill strata, the downward displacement of the soil around the pile is greater than that of the pile itself, which leads to an increase in negative friction, affecting the bearing capacity and settlement of the pile. Existing technologies are difficult to completely eliminate negative friction and are complex or costly to implement.
The structure employs a drag-reducing isolation structure, including precast piles, drag-reducing isolation materials, an isolation protective layer, and an energy circulation channel. A high-temperature medium is injected through an energy medium pump, and the drag-reducing isolation material slides due to temperature changes, reducing the impact of negative skin friction. This is achieved through multiple active drag reductions.
It effectively reduces negative skin friction, minimizes uneven settlement, improves safety and construction efficiency, reduces construction costs, and has continuous engineering application value.
Smart Images
Figure CN117627058B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pile foundation construction technology, and in particular to a construction method for a drag-reducing isolation structure applied to precast piles. Background Technology
[0002] Pile foundations are widely used in modern civil engineering due to their high vertical stiffness and bearing capacity, low settlement, and ability to withstand certain horizontal loads. However, when constructing pile foundations in soft soil or special soil strata (such as deep fill strata), the downward displacement of the surrounding soil often exceeds the downward displacement of the pile itself due to factors such as soil consolidation under its own weight, subsidence, lowering of the groundwater level, or surface overloading. This results in downward friction on the pile, creating a downward tension load on the pile sides—the so-called negative friction. The presence of negative friction increases the load on the pile, reduces the bearing capacity of the compression pile, and may lead to excessive settlement, causing building tilting and cracking, directly affecting the functionality and safety of the engineering structure. Therefore, reducing negative friction on the pile has become a key concern in the engineering field.
[0003] Currently, commonly used methods for eliminating negative skin friction are mainly divided into two categories: one is to control the source of negative skin friction, that is, to eliminate the harmfulness of the soil itself that is prone to generating negative friction through foundation treatment methods (dynamic compaction, preloading consolidation, etc.). This method has a long construction cycle and is generally not effective for deep soil layers. The other is to isolate the pile body from the surrounding soil. This type of method is more commonly used, including coating the pile surface with an asphalt film, installing unloading sleeves, installing protective sleeves, and driving isolation piles. This type of method has a more complex processing technology, which increases the manufacturing cost of the pile. While reducing negative friction, it also reduces positive friction.
[0004] Chinese invention patent CN201710668378.2 describes a construction method for reducing negative skin friction of pipe piles, including the following steps: Step 1: Estimating the depth of the neutral point of negative skin friction, prefabricating or processing connecting components. The connecting components are used to connect the upper and lower pipe piles. The lower part of the connecting components is fixedly connected to the lower pipe pile, and the upper part is sleeved with the upper pipe pile; Step 2: Site leveling and pre-filling; Step 3: Pipe pile construction; Step 4: Foundation and building construction, thus reducing negative skin friction. The connecting components allow for settlement space to reduce the impact of negative skin friction. However, the reliability of the external structure cannot be guaranteed, and settlement is a long-term process. If the settlement is less than the preset value, the pile bearing capacity is significantly reduced; if the settlement is greater than the preset value, the pile is still affected by negative skin friction, and the problem is not effectively solved.
[0005] Chinese utility model patent CN201822098968.9 describes an enlarged-base composite pipe pile structure for reducing negative skin friction in backfill strata, including a pile hole (1), pipe piles (2), an isolation layer (3), a centering support (4), concrete (7), and backfill (5). Pipe piles (2) are installed inside the pile hole (1). Concrete (7) is poured into the pile hole below the neutral point (6), and backfill (5) is used to fill the space between the pipe piles above the neutral point (6) and the pile hole. Although an isolation layer is set above the neutral point, and backfill is used to reduce negative skin friction, the isolation layer still cannot effectively eliminate negative skin friction.
[0006] In summary, the technology for eliminating negative skin friction in deep soft soil layers and backfilled areas still requires further research. Although many scholars have conducted extensive research and achieved some results, the methods for eliminating negative skin friction are still one-off, or incomplete, and are not implemented simultaneously with the surrounding soil. Based on this, this invention proposes a construction method for a drag-reducing isolation structure applied to precast piles. This method can actively reduce the impact of negative skin friction and can be used continuously and multiple times, with good drag-reduction effects. Summary of the Invention
[0007] To address the aforementioned technical problems in existing technologies, this invention proposes a construction method for a drag-reducing isolation structure applied to precast piles, overcoming the shortcomings of existing technologies. It can effectively solve the problem of settlement during and after construction in soft soil or filled soil areas. Furthermore, through multiple active drag reductions, it reduces the impact of negative skin friction on precast piles, lowers the possibility of uneven settlement, and increases safety margins, demonstrating significant engineering application and promotional value.
[0008] To achieve the above objectives, the present invention adopts the following technical solution:
[0009] A drag-reducing isolation structure for precast piles is characterized by comprising a precast pile, drag-reducing isolation material, an isolation protective layer, an energy circulation channel, and an energy medium pump; the drag-reducing isolation material is uniformly distributed on the surface of the precast pile, and the isolation protective layer wraps around the precast pile and the drag-reducing isolation material; the energy circulation channel is located inside the precast pile, and the energy circulation channel is connected to the energy medium pump through a pipeline.
[0010] Preferably, the exterior of the isolation and protective layer contains soil or mixed materials in different states. In particular, the soil or mixed materials include in-situ soil, disturbed soil, cement-soil mixture, concrete, and mortar, and the isolation and protective layer is bonded to the soil or mixed materials.
[0011] Preferably, the precast piles include precast hollow concrete pipe piles, precast solid concrete pipe piles, precast hollow concrete square piles, precast solid concrete square piles, and precast hollow steel pipe piles.
[0012] Preferably, the drag-reducing and insulating material includes one of mineral oil, synthetic oil, and waxy lubricant.
[0013] Preferably, the material of the protective layer includes one of polytetrafluoroethylene, polyethylene, and polypropylene.
[0014] Preferably, the energy circulation channel is provided with 2 to 4 U-shaped loops in each precast pile, and the energy circulation channel is a metal pipe or a composite material pipe;
[0015] When the energy circulation channel is made of metal, if the precast pile is a precast concrete hollow pipe pile or a precast concrete hollow square pile, the energy circulation channel is installed inside the concrete material or inside the hollow structure of the hollow precast pile and is in close contact with the concrete structure; if the precast pile is a precast hollow steel pipe pile, the energy circulation channel is installed inside the hollow structure of the precast pile and is in close contact with the steel pipe pile; if the precast pile is a precast solid concrete pipe pile or a precast solid concrete square pile, the energy circulation channel is installed inside the concrete material and close to the outer surface of the precast pile.
[0016] When the energy circulation channel is made of composite material, if the precast pile is a precast concrete hollow pipe pile or a precast concrete hollow square pile, the energy circulation channel is installed inside the concrete material and close to the outer surface of the precast pile; if the precast pile is a precast hollow steel pipe pile, the energy circulation channel is installed inside the hollow structure of the precast pile and in close contact with the steel pipe pile; if the precast pile is a precast solid concrete pipe pile or a precast solid concrete square pile, the energy circulation channel is installed inside the concrete material and close to the outer surface of the precast pile.
[0017] A construction method for a drag-reducing and isolation structure applied to precast piles, characterized by the following specific construction steps:
[0018] Step 1: Fabrication of precast piles
[0019] During the fabrication of precast piles, energy circulation channels are embedded within them. The specific embedding method is as follows:
[0020] When the energy circulation channel is made of metal, if it is installed inside a precast concrete hollow or solid pile, the energy circulation channel is tied into the precast pile reinforcement cage before the precast pile is centrifuged and precast together with the precast pile; if it is installed in the hollow part of a precast concrete hollow pile, the energy circulation channel is welded to the precast pile reinforcement cage with connecting steel bars before the precast pile is centrifuged; if it is installed in the hollow part of a precast steel pipe pile, the energy circulation channel is directly welded to the inner surface of the precast steel pipe pile.
[0021] When the energy circulation channel is made of composite material, if it is installed inside a precast concrete hollow or solid pile, the energy circulation channel is tied into the precast pile reinforcement cage before the precast pile is centrifuged and precast together with the precast pile; if it is installed in the hollow part of a precast concrete hollow pile, the energy circulation channel is installed in the metal clip by welding it to the precast pile reinforcement cage before the precast pile is centrifuged; if it is installed in the hollow part of a precast steel pipe pile, the energy circulation channel is installed in the metal clip by welding it to the inner surface of the steel pipe pile before centrifuging.
[0022] Step 2: Fabrication of drag-reducing and isolation materials
[0023] Different drag-reducing materials are selected based on the desired isolation effect. Mineral oil and wax lubricants are commonly used materials on the market. Synthetic oil is processed in the following way to ensure that mineral oil, synthetic oil, and wax lubricants remain in a liquid state at room temperature above 30°C, and gradually turn into a grease-like solid state below 30°C.
[0024] (1) Vegetable oil is produced by pressing plants or plant seeds, mainly including peanut oil, rapeseed oil, corn oil and sesame oil;
[0025] (2) Pre-treat the vegetable oil to remove moisture and impurities;
[0026] (3) Carry out the hydrogenation reaction. Add nickel as a catalyst in the reactor, control the temperature between 200℃ and 350℃, and control the pressure between 3MPa and 5MPa, so that the treated vegetable oil and hydrogen can react fully. The reaction time is 2 hours to 3 hours.
[0027] (4) After the reaction is complete, remove the catalyst and refine the mixture at high temperature, with the temperature controlled between 400℃ and 450℃. Remove the extract and cool it to room temperature.
[0028] (5) The extract obtained in step (4) undergoes isolithoexchange with ethanol at 60-70°C, and sodium hydroxide is added as a catalyst. After the reaction is complete, the modified vegetable oil is obtained by distillation.
[0029] (6) Modified vegetable oil accounts for 75%~85%, then add additives to change viscosity and flowability, such as polymethyl methacrylate or kerosene, either of which can be selected, accounting for 2%~3%, then add dispersant, either polyvinyl alcohol or polyacrylate, accounting for 3%~6%, then add emulsifier, polyoxyethylene derivative, accounting for 3%~6%, then add flow improver, polyolefin copolymer, accounting for 7%~10%, and after mixing evenly, obtain synthetic oil;
[0030] Step 3: Create an isolation and protective layer
[0031] Polytetrafluoroethylene, polyethylene, and polypropylene are extruded to form a film structure, and the film is made into different thicknesses from 0.01 mm to 2 mm according to the requirements.
[0032] Step 4: Apply drag-reducing and insulating material
[0033] First, clean the impurities from the surface of the precast pile. Then, use a brush to evenly apply any one of mineral oil, synthetic oil, or wax lubricant to the outer surface of the precast pile.
[0034] Step 5: Apply an isolation and protective layer
[0035] Within 30 minutes of applying the drag-reducing isolation material, wrap the isolation protective layer around the surface of the precast pile, and ensure that the drag-reducing isolation material is evenly distributed between the precast pile and the isolation protective layer;
[0036] Step Six: Implanting the treated precast piles
[0037] The treated precast piles are inserted into the in-situ soil or other materials; when two precast piles need to be connected, the energy circulation channel is connected at the same time. After the two precast piles are connected, drag-reducing isolation material is applied on site and an isolation protective layer is wrapped in time.
[0038] Step 7: Energy circulation reduces negative friction resistance
[0039] When the soil around the pile settles to 1-2cm, a high-temperature medium is injected into the energy circulation channel through an energy medium pump. After heat exchange, the pile temperature increases to over 30℃, the drag-reducing isolation material becomes liquid, and the precast pile and the isolation protective layer slide completely, thus removing the pull-down load acting on the precast pile.
[0040] Step 8: Continuous Maintenance
[0041] Within one year after construction, energy cycling is performed every month to eliminate negative friction resistance. After one year, energy cycling is performed every three months. After three years, energy cycling is performed every six months. After five years, energy cycling is performed every twelve months.
[0042] Preferably, the energy circulation process in step seven to eliminate negative skin friction is further explained as follows: After the pile is installed, due to the heat released by construction friction and the heat released by the hydration of other materials, the mineral oil, synthetic oil, and wax lubricant remain in a liquid state. After hydration is completed, as the pile exchanges heat with the surrounding environment, the temperature gradually decreases to below 30°C. At this time, the surrounding soil gradually undergoes consolidation and settlement, and the cement-soil pile is subjected to a downward load. At this time, the mineral oil, synthetic oil, and wax lubricant are all in a solid state, and part of the downward load is transferred to the precast pile. At this time, a high-temperature medium is injected into the energy circulation channel through an energy medium pump to increase the pile body temperature and remove the downward load acting on the precast pile.
[0043] Preferably, the energy circulation channels between different piles are connected in batches, with 1 to 10 piles connected, and the connection lines of the energy circulation channels are reasonably selected according to the pile distribution.
[0044] Preferably, the drag-reducing and isolation material is one of the following: thermosensitive degrading material, electromagnetic induction degrading material, and vibration degrading material. Depending on the drag-reducing and isolation material, heat exchange, electricity, and vibration are used to achieve the material's deformation, ultimately achieving the effect of drag reduction and isolation.
[0045] The beneficial technical effects of this invention are as follows:
[0046] (1) By setting up drag-reducing isolation materials and isolation protective layers between cement soil piles and precast piles, a mutually sliding structure is formed; (2) Through in-depth research on drag-reducing isolation materials, materials whose state changes with temperature are prepared, thereby ensuring the effectiveness of drag-reducing structure; (3) By setting up energy circulation channels and energy medium pumps, and by actively reducing drag multiple times, the influence of negative friction on precast piles is reduced, the possibility of uneven settlement is reduced, and the safety margin is increased, which has good engineering application value and promotion value. Attached Figure Description
[0047] Figure 1 This is a schematic diagram of the overall structure in which the energy circulation channel is set inside the concrete of the precast pile in the construction method of the drag-reducing isolation structure applied to precast piles according to the present invention.
[0048] Figure 2 This is a schematic diagram of the overall structure of an energy circulation channel located within the hollow part of the precast pile concrete in a construction method for a drag-reducing and isolation structure applied to precast piles according to the present invention.
[0049] In the diagram: 1-Precast pile, 2-Drag reduction and isolation material, 3-Isolation and protection layer, 4-Soil or mixed material, 5-Energy circulation channel, 6-Energy medium pump. Detailed Implementation
[0050] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:
[0051] Example 1: A drag-reducing and isolation structure for precast piles is applied to composite piles, specifically, a precast pile 1 with a drag-reducing and isolation structure is inserted into the middle of a cement-soil mixing pile. The specific construction is as follows:
[0052] like Figures 1-2 As shown, a drag-reducing isolation structure applied to precast piles includes a precast pile 1, a drag-reducing isolation material 2, an isolation protective layer 3, an energy circulation channel 5, and an energy medium pump 6. The drag-reducing isolation material 2 is evenly distributed on the surface of the precast pile 1, and the isolation protective layer 3 wraps around the precast pile 1 and the drag-reducing isolation material 2. The energy circulation channel 5 is located inside the precast pile 1, and the energy circulation channel 5 is connected to the energy medium pump 6 through a pipe.
[0053] Preferably, the soil or mixed material 4 outside the isolation and protective layer 3 is cement-soil material, that is, the isolation and protective layer 3 is bonded to the cement-soil mixing pile.
[0054] Preferably, the precast pile 1 includes precast hollow concrete pipe piles, precast solid concrete pipe piles, precast hollow concrete square piles, precast solid concrete square piles, and precast hollow steel pipe piles.
[0055] Preferably, the drag-reducing and insulating material 2 includes one of mineral oil, synthetic oil, and waxy lubricant.
[0056] Preferably, the material of the isolation and protective layer 3 includes one of polytetrafluoroethylene, polyethylene, and polypropylene.
[0057] Preferably, the energy circulation channel 5 is provided with 2 to 4 U-shaped loops in each precast pile 1, and the energy circulation channel 5 is a metal pipe or a composite material pipe;
[0058] When the energy circulation channel 5 is made of metal, if the precast pile 1 is a precast concrete hollow pipe pile or a precast concrete hollow square pile, the energy circulation channel 5 is installed inside the concrete material or inside the hollow structure of the hollow precast pile 1 and is in close contact with the concrete structure; if the precast pile 1 is a precast hollow steel pipe pile, the energy circulation channel 5 is installed inside the hollow structure of the precast pile 1 and is in close contact with the steel pipe pile; if the precast pile 1 is a precast concrete solid pipe pile or a precast concrete solid square pile, the energy circulation channel 5 is installed inside the concrete material and close to the outer surface of the precast pile 1.
[0059] When the energy circulation channel 5 is made of composite material, if the precast pile 1 is a precast concrete hollow pipe pile or a precast concrete hollow square pile, the energy circulation channel 5 is installed inside the concrete material and close to the outer surface of the precast pile 1; if the precast pile 1 is a precast hollow steel pipe pile, the energy circulation channel 5 is installed inside the hollow structure of the precast pile 1 and in close contact with the steel pipe pile; if the precast pile 1 is a precast concrete solid pipe pile or a precast concrete solid square pile, the energy circulation channel 5 is installed inside the concrete material and close to the outer surface of the precast pile 1.
[0060] A construction method for a drag-reducing and isolation structure applied to precast piles, characterized by the following specific construction steps:
[0061] Step 1: Fabrication of precast piles 1
[0062] During the fabrication of precast pile 1, the energy circulation channel 5 is embedded, and the specific embedding method is as follows:
[0063] When the energy circulation channel 5 is made of metal, if it is installed inside a precast concrete hollow or solid pile, the energy circulation channel 5 is tied into the reinforcing cage of the precast pile 1 before the precast pile 1 is centrifuged, and precast together with the precast pile 1; if it is installed in the hollow part of a precast concrete hollow pile, the energy circulation channel 5 is connected to the reinforcing cage of the precast pile 1 by welding connecting steel bars before the precast pile 1 is centrifuged; if it is installed in the hollow part of a precast steel pipe pile, the energy circulation channel 5 is directly welded to the inner surface of the precast steel pipe pile.
[0064] When the energy circulation channel 5 is made of composite material, if it is installed inside a precast concrete hollow or solid pile, the energy circulation channel 5 is tied into the reinforcing cage of the precast pile 1 before centrifugation and precast together with the precast pile 1; if it is installed in the hollow part of a precast concrete hollow pile, the energy circulation channel 5 is installed in the metal clip by welding it to the reinforcing cage of the precast pile 1 before centrifugation; if it is installed in the hollow part of a precast steel pipe pile, the energy circulation channel 5 is installed in the metal clip by welding it to the inner surface of the steel pipe pile before centrifugation.
[0065] Step 2: Fabrication of drag-reducing and isolation materials 2
[0066] Different drag-reducing isolation materials are selected according to different isolation effects. Among them, mineral oil and wax lubricants are commonly used materials on the market. Synthetic oil is processed in the following way to ensure that mineral oil, synthetic oil, and wax lubricants are in a liquid state at room temperature above 30°C, and gradually become grease-like solid state below 30°C.
[0067] (1) Vegetable oil is produced by pressing plants or plant seeds, mainly including peanut oil, rapeseed oil, corn oil and sesame oil;
[0068] (2) Pre-treat the vegetable oil to remove moisture and impurities;
[0069] (3) Carry out the hydrogenation reaction. Add nickel as a catalyst in the reactor, control the temperature between 200℃ and 350℃, and control the pressure between 3MPa and 5MPa, so that the treated vegetable oil and hydrogen can react fully. The reaction time is 2 hours to 3 hours.
[0070] (4) After the reaction is complete, remove the catalyst and refine the mixture at high temperature, with the temperature controlled between 400℃ and 450℃. Remove the extract and cool it to room temperature.
[0071] (5) The extract obtained in step (4) undergoes isolithoexchange with ethanol at 60-70°C, and sodium hydroxide is added as a catalyst. After the reaction is complete, the modified vegetable oil is obtained by distillation.
[0072] (6) Modified vegetable oil accounts for 75%~85%, then add additives to change viscosity and flowability, such as polymethyl methacrylate or kerosene, either of which can be selected, accounting for 2%~3%, then add dispersant, either polyvinyl alcohol or polyacrylate, accounting for 3%~6%, then add emulsifier, polyoxyethylene derivative, accounting for 3%~6%, then add flow improver, polyolefin copolymer, accounting for 7%~10%, and after mixing evenly, obtain synthetic oil;
[0073] Step 3: Create an isolation and protective layer 3
[0074] Polytetrafluoroethylene, polyethylene, and polypropylene are extruded to form a film structure, and the film is made into different thicknesses from 0.01 mm to 2 mm according to the requirements.
[0075] Step 4: Apply drag-reducing and insulating material 2
[0076] First, clean the impurities from the surface of the precast pile 1. Then, apply any one of mineral oil, synthetic oil, or wax lubricant evenly to the outer surface of the precast pile 1 using a brush.
[0077] Step 5: Apply an isolation and protective layer 3
[0078] Within 30 minutes of applying the drag-reducing isolation material 2, wrap the isolation protective layer 3 around the surface of the precast pile 1, and ensure that the drag-reducing isolation material 2 is evenly distributed between the precast pile 1 and the isolation protective layer 3.
[0079] Step Six: Implanting the treated precast pile 1
[0080] The treated precast pile 1 is inserted into the cement-soil mixing pile; when two precast piles 1 need to be connected, the energy circulation channel 5 is connected at the same time. After the two precast piles 1 are connected, the drag-reducing isolation material 2 is applied on site, and the isolation protective layer 3 is wrapped in time.
[0081] Step 7: Energy circulation reduces negative friction resistance
[0082] When the soil around the pile settles to 1-2cm, the high-temperature medium is injected into the energy circulation channel 5 through the energy medium pump 6. After heat exchange, the temperature of the pile increases to more than 30℃, the drag-reducing isolation material 2 becomes liquid, the precast pile 1 and the isolation protective layer 3 slide completely, and the pull-down load acting on the precast pile 1 is removed.
[0083] Step 8: Continuous Maintenance
[0084] Within one year after construction, energy cycling is performed every month to eliminate negative friction resistance. After one year, energy cycling is performed every three months. After three years, energy cycling is performed every six months. After five years, energy cycling is performed every twelve months.
[0085] Preferably, the energy circulation process in step seven to eliminate negative frictional resistance is further explained as follows: After the pile is installed, due to the heat released by construction friction and the heat released by the hydration of other materials, the mineral oil, synthetic oil, and wax lubricant remain in a liquid state. After hydration is completed, as the pile exchanges heat with the surrounding environment, the temperature gradually decreases to below 30°C. At this time, the surrounding soil gradually undergoes consolidation and settlement over time, and the cement-soil pile is subjected to a downward load. At this time, the mineral oil, synthetic oil, and wax lubricant are all in a solid state, and part of the downward load is transferred to the precast pile 1. At this time, the high-temperature medium is injected into the energy circulation channel 5 through the energy medium pump 6 to increase the temperature of the pile body and remove the downward load acting on the precast pile 1.
[0086] Preferably, the energy circulation channel 5 between different piles is equipped with batch connection, with the number of connected piles being 1 to 10, and the connection line of the energy circulation channel 5 is reasonably selected according to the pile distribution.
[0087] Example 2: A drag-reducing and isolation structure for precast piles is applied to composite piles, specifically, a precast pile 1 with a drag-reducing and isolation structure is inserted into the middle of a cement-soil mixing pile. The specific construction is as follows:
[0088] like Figures 1-2 As shown, an electric conductor is laid in the energy circulation channel 5. The resistance-reducing isolation material is an electromagnetic induction denaturing material, which works on the same principle as the thermosensitive denaturing material. The original heat exchange medium is changed to an electric current, and finally, when the current is applied, the electromagnetic induction causes the material to denature into a fluid-like substance, thereby achieving resistance reduction and isolation.
[0089] Example 3: A drag-reducing and isolation structure for precast piles is applied in pipe pile engineering. The specific construction is as follows:
[0090] like Figures 1-2 As shown, by placing an excitation sphere in the energy channel, the drag-reducing isolation material is an excitation-modified material, which is the same as the principle of the thermosensitive modulated material. When drag reduction is required, the excitation sphere is activated to move within the precast pile 1, and finally the excitation-modified material is transformed into a fluid-like substance, thereby achieving drag reduction and isolation.
[0091] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention are also within the protection scope of the present invention.
Claims
1. A construction method for a drag-reducing and isolation structure applied to precast piles, characterized in that, The system includes precast piles, drag-reducing and isolation materials, an isolation and protective layer, an energy circulation channel, and an energy medium pump. The drag-reducing and isolation materials are evenly distributed on the surface of the precast piles, and the isolation and protective layer wraps around both the precast piles and the drag-reducing and isolation materials. The energy circulation channel is located inside the precast piles and is connected to the energy medium pump via a pipeline. The specific construction steps are as follows: Step 1: Fabrication of precast piles During the fabrication of precast piles, energy circulation channels are embedded within them. The specific embedding method is as follows: When the energy circulation channel is made of metal: when installed inside a precast concrete hollow or solid pile, the energy circulation channel is tied into the precast pile reinforcement cage before the precast pile is centrifuged and precast together with the precast pile; when installed in the hollow part of a precast concrete hollow pile, the energy circulation channel is welded to the precast pile reinforcement cage with connecting steel bars before the precast pile is centrifuged; when installed in the hollow part of a precast steel pipe pile, the energy circulation channel is directly welded to the inner surface of the precast steel pipe pile. When the energy circulation channel is made of composite material: when installed inside a precast concrete hollow or solid pile, the energy circulation channel is tied into the precast pile reinforcement cage before the precast pile is centrifuged and precast together with the precast pile; when installed in the hollow part of a precast concrete hollow pile, the energy circulation channel is installed inside the metal clip by welding to the precast pile reinforcement cage before the precast pile is centrifuged; when installed in the hollow part of a precast steel pipe pile, the energy circulation channel is installed inside the metal clip by welding to the inner surface of the steel pipe pile with metal clips. Step 2: Fabrication of drag-reducing and isolation materials Different drag-reducing materials are selected based on different isolation effects. Synthetic oils are processed in the following manner to ensure that mineral oils, synthetic oils, and wax lubricants remain in a liquid state above room temperature (30°C), and gradually change to a grease-like solid state below 30°C: (1) Vegetable oil is produced by pressing plants or plant seeds, mainly including peanut oil, rapeseed oil, corn oil and sesame oil; (2) Pre-treat the vegetable oil to remove moisture and impurities; (3) Carry out the hydrogenation reaction. Add nickel as a catalyst in the reactor, control the temperature between 200℃ and 350℃, and control the pressure between 3MPa and 5MPa, so that the treated vegetable oil and hydrogen can react fully. The reaction time is 2 hours to 3 hours. (4) After the reaction is complete, remove the catalyst and refine the mixture at high temperature, with the temperature controlled between 400℃ and 450℃. Remove the extract and cool it to room temperature. (5) The extract obtained in step (4) undergoes isolithoexchange with ethanol at 60-70°C, and sodium hydroxide is added as a catalyst. After the reaction is complete, the modified vegetable oil is obtained by distillation. (6) Modified vegetable oil accounts for 75%~85%, then add additives to change viscosity and flowability, such as polymethyl methacrylate or kerosene, accounting for 2%~3%, then add one of the dispersants, polyvinyl alcohol or polyacrylate, accounting for 3%~6%, then add the emulsifier, polyoxyethylene derivative, accounting for 3%~6%, then add the flow improver, polyolefin copolymer, accounting for 7%~10%, and mix evenly to obtain synthetic oil; Step 3: Create an isolation and protective layer Polytetrafluoroethylene, polyethylene, and polypropylene are extruded to form a film structure, and the film is made into different thicknesses from 0.01 mm to 2 mm according to the requirements. Step 4: Apply drag-reducing and insulating material First, clean the impurities from the surface of the precast pile. Then, use a brush to evenly apply any one of mineral oil, synthetic oil, or wax lubricant to the outer surface of the precast pile. Step 5: Apply an isolation and protective layer Within 30 minutes of applying the drag-reducing isolation material, wrap the isolation protective layer around the surface of the precast pile, and ensure that the drag-reducing isolation material is evenly distributed between the precast pile and the isolation protective layer; Step Six: Implanting the treated precast piles The treated precast piles are then inserted into the in-situ soil or other materials. When two precast piles need to be connected, the energy circulation channel is connected at the same time. After the two precast piles are connected, drag-reducing isolation material is applied on site and an isolation protective layer is wrapped in time. Step 7: Energy circulation reduces negative friction resistance When the soil around the pile settles to 1-2cm, a high-temperature medium is injected into the energy circulation channel through an energy medium pump. After heat exchange, the pile temperature increases to over 30℃, the drag-reducing isolation material becomes liquid, and the precast pile and the isolation protective layer slide completely, thus removing the pull-down load acting on the precast pile. Step 8: Continuous Maintenance Within one year after construction, energy cycling is performed every month to eliminate negative friction resistance. After one year, energy cycling is performed every three months. After three years, energy cycling is performed every six months. After five years, energy cycling is performed every twelve months.
2. The construction method for a drag-reducing and isolation structure applied to precast piles according to claim 1, characterized in that: The outer surface of the isolation and protective layer contains soil or mixed materials in different states. The isolation and protective layer is bonded to the soil or mixed materials in different states. The soil in different states includes in-situ soil and disturbed soil. The mixed materials include cement-soil mixtures, concrete, and mortar.
3. The construction method for a drag-reducing and isolation structure applied to precast piles according to claim 1, characterized in that: The energy circulation channels between different piles can be connected in batches, with the number of connected piles ranging from 1 to 10. The connection lines of the energy circulation channels are selected reasonably according to the distribution of the piles.
4. The construction method for a drag-reducing and isolation structure applied to precast piles according to claim 1, characterized in that: Drag-reducing and isolation materials are one of the following: thermosensitive modulating materials, electromagnetic induction modulating materials, and vibration modulating materials. Depending on the type of drag-reducing and isolation material, heat exchange, electric current, and vibration are used to modify the material, ultimately achieving the effect of drag reduction and isolation.