Permanent and temporary combined foundation reinforcement method

Abstract

The invention discloses a permanent and temporary combined foundation reinforcement method which comprises the following steps: S1, determining design parameters: performing field investigation on a field environment, identifying an original building, and determining the parameters after structural analysis; s2, according to the parameters determined in the step S2, paying-off and line inspection, water drill positioning, pile pressing hole digging, hole opening reinforcing, water drill cutting and edge cleaning are conducted on site; s3, according to the positions of the pile holes determined in the step S2, 12 M32 anchor rods are arranged near each pile hole, the anchoring length is 500 mm, and KL-80 cementing materials are adopted; S4, according to the positions of the anchor rods in the step 3, a pile pressing frame is installed; and S5, after the pile is pressed to the designed final pile pressing force, certain pressure stress is kept for pile sealing, and KL-40 materials are poured. By means of the method, it can be effectively guaranteed that structural settlement under different foundation forms meets the requirement, safe use of the existing building is guaranteed, meanwhile permanent and temporary combination is considered, the influence on the existing building is reduced, and the reinforcement cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and particularly to a foundation reinforcement method combining permanent and temporary structures. Background Art

[0002] According to the field investigation, in the current building foundation reinforcement projects, the most commonly used methods mainly include increasing the foundation bottom area method, anchor rod jacked pile method, high-pressure jet grouting method, root pile method, lime pile method, etc. In the reconstruction and expansion projects, while ensuring the normal use safety of the existing buildings, it is also necessary to consider the impact of the expansion project on the existing buildings and avoid damaging the original structure. The above single methods can no longer fully meet the foundation reinforcement treatment under the complex on-site conditions. Summary of the Invention

[0003] The purpose of the present invention is to provide a foundation reinforcement method combining permanent and temporary structures in view of the deficiencies of the prior art.

[0004] The technical solution adopted by the present invention to solve the above technical problems is as follows: A foundation reinforcement method combining permanent and temporary structures, comprising the following steps: S1. Determine the design parameters: Conduct on-site investigations on the site environment, identify the original buildings, and determine the parameters after structural analysis; S2. According to the parameters determined in step S2, conduct layout verification, water drill positioning, opening pile pressing holes, hole opening reinforcement, water drill cutting, and edge cleaning on the site; S3. According to the pile hole positions determined in step S2, arrange 12 M32 anchor rods near each pile hole, with an anchoring length of 500 mm, and use KL-80 cementitious material; S4. Install the pile pressing frame according to the positions of the anchor rods in step 3; S5. After the pile is pressed to the designed final pile pressing force, maintain a certain compressive stress for pile sealing and pour KL-40 material.

[0005] Preferably, step S2 includes the following steps: S21. Layout verification: Use a chalk line to mark the positions of the water drill holes on the foundation slab where pile pressing is required according to the drawing requirements, and recheck the positions of the cutting hole lines; S22. Water drill positioning: Fix the drill on the concrete surface outside the cutting hole line with anchor rods according to the position of the hole line; S23. Hole opening reinforcement: Reinforce the edges of the newly opened holes according to the requirements of the construction drawings; S24. Water drill cutting: Connect the power supply of the water drill, place the water drill bit inside the cutting hole line, and drill and cut side by side along the line; S25. Edge cleaning: Use a pneumatic hammer to remove the redundant concrete inside the cutting line of the hole opening.

[0006] Preferably, step S3 comprises the following steps: S31. Laying out and positioning: Mark the location and model of the drilling holes for embedding reinforcement according to the design requirements; S32. Drilling: Drilling should be done with a water drill. If the steel bars cannot be cut, the hole position should be adjusted to avoid them. For high-efficiency structural adhesives or KL-80 cementitious materials, the drilling diameter is d+4~8mm, and the anchoring length is 20d / 10d. The hole wall should be kept dry. S33, hole cleaning: After drilling, use compressed air to blow out the dust in the hole, then use a brush to clean the hole wall, and then check the hole depth and hole diameter. After processing, plug the hole with silk cotton to keep the hole dry; S34, steel bar rust removal: the rust within the anchorage length of the steel bar should be removed and polished to bring out the metallic luster; the anchorage length of the embedded steel bar is 22d, the reserved length should be able to meet the lap length required by the design, and the two adjacent bars should be staggered by 35d; after the steel bar processing is completed, the rust treatment should be carried out; for ordinary steel bars without serious corrosion, the floating rust on the embedded part should be cleaned with a wire brush, and severely rusted steel bars cannot be used as embedded steel bars. If the steel bars are stained with oil, they should be cleaned with acetone; S35, Adhesive preparation: Structural adhesive is composed of two components, A and B. Take a clean container and weighing scale to mix according to the mixing ratio in the instructions, and stir with a stirrer for about 5-10 minutes until the color is uniform; S36, rebar planting: pinch the prepared anchoring glue into strips and put them into the hole. If the hole is deep, use thin steel bars to lightly tamp it. The amount of anchoring glue should be such that a small amount of material overflows after the steel bar is inserted. Insert the steel bar that has been rust-removed into the hole filled with structural glue, rotate the steel bar, insert and pull it out repeatedly, and stir the dust remaining on the hole wall into the structural glue until the surface of the structural glue attached to the steel bar is free of dust. Straighten and fix the steel bar; S37, curing and protection: Structural adhesive can be cured well at room temperature and low temperature. If the curing temperature is around 25℃, it can be used under load in 48 hours; if the curing temperature is around 5℃, it can be used under load in 72 hours; the steel bars should not be disturbed within 12 hours after planting, and if there is a major disturbance, the steel bars should be re-planted; S38. Determine the time for rebar planting: The entire process from mixing the glue to rebar planting is completed within 30 minutes. The next process can be carried out 24 hours after the rebar planting is completed. The initial setting time of the glue can be controlled by increasing or decreasing the amount of material B (curing agent); S39. Inspection: Use jack, anchor and reaction frame system to conduct pull-out test.

[0007] Preferably, in step S4, the soil geological conditions on site should be clearly understood before the pile pressing construction. The pile pressing frame should be kept vertical, and the nuts of the anchor bolts should be tightened evenly. The pile section should be kept vertical when in place, so that the jack and the pile axis are on the same vertical line. During the pile pressing construction process, axial compression should be maintained at all times. Electric jacks are used for pile pressing, and the pile pressing construction should be carried out symmetrically to prevent uneven foundation stress. When pressing the pile, the jack must be kept perpendicular to the pile section axis. Steel plate pads should be set between the jack and the pile top. The pile joints adopt welded pile joints. When connecting the upper and lower piles, the upper and lower pile faces must be aligned. When connecting the piles, the axes of the upper and lower piles should be kept consistent to shorten the pile connection time. When connecting the piles, the upper and lower sections should be aligned to ensure uniform force on the joint contact surface. Inside the steel pipe column at the pile connection, a ϕ250*6 internal steel casing is provided.

[0008] Preferably, step S5 includes the following steps: S51. When the pile is pressed to the designed final pile pressing force, maintain a certain compressive stress for pile sealing and pour KL-40 material. After the pile sealing material meets the strength requirements, remove the bearing equipment. If the pile top is not pressed to the designed position, the exposed pile head must be cut off; S52. Cleaning the pile pressing hole: Clean up the sundries, soil, and the original formwork in the pile pressing hole; S53. Chiseling the inverted bell mouth at the pile opening: To ensure the punching shear effect of the connection surface between the pile sealing concrete and the original pile cap, chisel the 300mm opening range of the pile hole into an inverted bell mouth with a smaller upper part and a larger lower part according to the design requirements. The bottom opening of the chiseled surface is about 40 - 60mm wider than the top opening on each side; S54. Installation of the pile sealing reaction frame and jack: After the chiseling of the pile sealing opening is completed, clean the opening, install a small pile pressing reaction frame for pile sealing on the original pre-buried screw of pile pressing using a connector, and set a pile sealing steel pipe on the steel pipe pile. The pile sealing steel pipe uses a 150*5 steel pipe. Set a jack between the pile sealing steel pipe and the reaction frame, and press the jack to the designed pile sealing force; S55. Pouring the slightly expanded KL-40 pile sealing concrete: After the pile sealing pressure of the steel pipe pile reaches the designed value, wet the pile sealing opening with water, and set a circle of 203 water-swelling waterproof glue at the groove. Then use KL-40 high-strength non-shrinking material for pile sealing pouring. The pouring surface is 150mm lower than the top of the pile cap; S56. Weld and restore the upper reinforcement of the original foundation slab at the pile top with the same specification. The welding requirements are determined according to the design drawing; S57. After the strength of the pile sealing concrete meets the design requirements, remove the pile sealing reaction frame and the jack, clean the floating ash and impurities on the surface of the pile pressing anchor rod, restore the upper reinforcement, and formwork and pour concrete in this area for protection.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: The permanent-temporary combined foundation reinforcement method described in the present invention changes the traditional single foundation reinforcement method. Through the analysis of structural settlement differences under different foundations, it is considered to utilize part of the structure of the existing building, avoiding unnecessary demolition and reconstruction, improving the resource utilization efficiency, comprehensively utilizing a variety of foundation reinforcement methods, and at the same time using special cementitious materials, which can effectively ensure the safety of the existing building during use and reduce the impact on the existing building; The present invention overcomes the problems of high cost of foundation reinforcement, narrow construction working surface, and great construction difficulty at present. At the same time, it can ensure the construction speed, shorten the reinforcement period, avoid irreversible structural safety impacts on the existing building, and reduce the comprehensive cost; The operation of the present invention is simple, the construction noise is small, reducing the impact of dust and noise pollution on the surrounding environment, effectively solving the contradiction among society, economy and environment caused by reinforcement, and having a certain reference effect on similar projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. In the accompanying drawings: Figure 1 is the process flow chart of the present invention; Figure 2 is the schematic diagram of the working principle of pile pressing of the present invention; Figure 3 is the schematic diagram of the arrangement of solid anchor rods of the present invention; Figure 4 is the schematic diagram of steel pipe piles of the present invention; Figure 5 is the schematic diagram of the seal pile waterproof joint. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0011] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the described embodiments.

[0012] Please refer to Figures 1 to 5, The specific application of a permanent-temporary combined foundation reinforcement method in the construction of a certain subway station. The existing building to be reinforced has one basement floor and three above-ground floors, with a frame structure. The foundation form is a pile-raft foundation, using ϕ500 prestressed pipe piles with a pile length of 35m. The raft slab is 500mm thick, and the raft slab concrete is C40 impermeable concrete. The basement car ramp part uses a raft foundation with a raft slab thickness of 600mm, and the car ramp raft slab concrete is C40 impermeable concrete. A 500mm thick 1:1 layered and tamped sand-gravel cushion + 100mm thick plain concrete cushion is provided under the raft slab. The glass curtain wall structure above the car ramp uses steel columns. The north steel columns act on the car ramp roof slab, and the south steel columns act on the original foundation beam with the original foundation beam size of 1m * 1m. During the excavation of the foundation pit for the peripheral expansion project, the car ramp and the curtain wall structure above it were monitored to have large settlements, and both the settlement amount and settlement rate were large. To ensure the subsequent safe use of the building, the subsequent use of the glass curtain wall, and the safety of surrounding pedestrians, etc., and considering the connection between the subsequent expansion project and the existing building, it is necessary to carry out foundation reinforcement treatment on it.

[0013] The process of a permanent-temporary combined foundation reinforcement method in this embodiment is as Figure 1 shown, and specifically includes the following steps: S1. Determine design parameters: Conduct on-site investigations on the site environment and appraise the original building. After structural analysis, determine the following parameters: At the car ramp, 6 A273 * 10 static pressure steel pipe piles are used, with a pile length of 31m, a pile pressing force of 1100kN, and a bearing capacity characteristic value of 550kN; At the glass curtain wall steel columns, 6 A273 * 10 static pressure steel pipe piles are used, with a length of 21m, a pile pressing force of 500kN, and a bearing capacity characteristic value of 250kN. The plane size of the foundation beam under the original columns is increased in section to 3m * 3m, and a surrounding beam structure is adopted. The connection surface between the new part and the original foundation is roughened, and C12 dowel bars are added. The enlarged part uses C30 concrete, and the post-grouting process at the pile end is adopted to further improve the bearing capacity of the pile foundation; S2. According to the parameters determined in step S2, carry out layout verification, water drill positioning, opening of pile pressing holes, hole reinforcement, water drill cutting, and edge cleaning on site, specifically including the following steps: S21. Layout verification: Use a chalk line to mark the positions of the water drill holes on the foundation slab at the positions where pile pressing is required according to the drawing requirements, and review the positions of the cutting hole lines; S22. Water drill positioning: According to the position of the hole line, fix the drill on the concrete surface outside the cutting hole line with a bolt; S23. Hole reinforcement: Reinforce the edges of the newly opened holes according to the requirements of the construction drawings; S24. Water drill cutting: Connect the power supply of the water drill, place the water drill bit inside the cutting hole line, and drill and cut side by side along the line; S25. Edge cleaning: Use a jackhammer to remove the excess concrete inside the cutting line of the hole opening. S3. According to the pile hole positions determined in step S2, arrange 12 M32 anchor bolts near each pile hole, with an anchorage length of 500 mm, and use KL-80 gelling material. The steps are as follows: S31. Setting out and positioning: Mark the drilling positions and types of the post-inserted bars according to the design requirements. However, if there are stressed steel bars on the base material, the drilling positions can be appropriately adjusted (preferably within 4d). S32. Drilling: It is advisable to use a water drill for drilling. If there are steel bars that cannot be cut, the hole positions should be adjusted to avoid them. For high-performance structural adhesives or KL-80 gelling materials, the drilling diameter is d + 4 - 8 mm, and the anchorage length is 20d / 10d, which can ensure that the post-inserted bars reach the yield point until they are pulled out. The hole wall of the drilling should preferably be kept dry, but slightly damp hole walls (no water accumulation in the holes) have basically no impact on the anchoring force. S33. After drilling, use compressed air to blow out the dust in the hole, then brush the hole wall with a brush (preferably repeat 2 times), then check the hole depth and diameter. After processing, plug the hole opening tightly with cotton wool to prevent water from flowing into the hole or other sundries from falling into it, and keep the hole dry. S34. Reinforcement rust removal: The rust within the anchorage length range of the reinforcement should be removed completely (it is also recommended to remove the blue outer skin of new reinforcement), and a metallic luster should be polished. Using an angle grinder and a wire wheel disc can achieve a faster removal speed. The post-inserted bar anchorage length is 22d, and the reserved length should be able to meet the lap length required by the design, depending on the specific situation, and the adjacent two bars should be staggered by 35d. After the reinforcement is processed, rust removal treatment should be carried out. For ordinary reinforcement without serious rust, use a wire brush to clean the floating rust on the embedded part. Severely rusted reinforcement cannot be used as post-inserted bars. If the reinforcement is stained with oil, clean it with acetone. S35. Adhesive preparation: The structural adhesive consists of two components, A and B. Take a clean container (plastic or metal basin, free of oil, water, and impurities) and a weighing scale, mix them according to the mixing ratio in the instruction manual, and use a stirrer to stir for about 5 - 10 minutes until the color is uniform (metallic gray). It is best to stir in the same direction to avoid mixing air to form bubbles as much as possible. The stirring teeth can be made by welding a cross-shaped Φ14 steel bar to the end of a jackhammer drill bit. S36. Post-inserting bars: The construction workers wear thread gloves or leather gloves, knead the prepared anchoring glue into strips and put them into the holes. If the holes are deeper, use a thin steel bar to gently tamp them. The filling amount of the anchoring glue should be such that there is a small amount of agent overflowing after inserting the reinforcement. This anchoring glue does not flow, and it is also easy to insert post-inserted bars in horizontal holes and inverted vertical holes. Insert the rust-removed reinforcement into the hole filled with structural adhesive, and rotate the reinforcement, repeatedly insert and pull out, stir the remaining dust on the hole wall into the structural adhesive until the surface of the structural adhesive attached to the reinforcement is free of dust. Straighten and fix the reinforcement, and do not disturb the reinforcement before the glue cures to avoid affecting the anchoring effect. S37. Curing and protection: The structural adhesive can be well cured at normal temperature and low temperature. If the curing temperature is about 25°C, it can be loaded for use after 48 hours. If the curing temperature is about 5°C, it can be loaded for use after 72 hours. The steel bars shall not be disturbed within 12 hours after the steel bars are implanted. If there is a large disturbance, it is advisable to re-implant the steel bars; S38. Determine the time for implanting steel bars: The initial setting time of the structural adhesive is very fast. The whole process from mixing the adhesive to implanting the steel bars should be completed within 30 minutes. The next process can be carried out 24 hours after the steel bars are implanted. After the structural adhesive begins to set and harden, it can no longer be used for implanting steel bars. If there are special requirements for the initial setting time, the initial setting time of the adhesive can be controlled by increasing or decreasing the amount of Component B (curing agent) according to the ambient temperature during use and the requirements for the use of the anchor. The amount of Component B has no obvious effect on the anchoring strength; S39. Inspection: The mechanical properties of the structural adhesive are excellent. Normal operation can achieve the result that the steel bar is pulled off while the anchoring end remains intact. Generally, a jack, an anchor and a reaction frame system are used for the pull-out test. Generally, the load is applied in stages to the standard value of the steel bar strength, and the test results are intuitive, reliable and simple.

[0014] S4. Before the pile pressing construction, the soil layer geological conditions on the site should be clearly understood. At the same time, the inspection of the equipment should be done well to ensure reliable use; the pile pressing frame should be kept vertical, and the nuts of the anchor bolts should be tightened evenly. The pile section must be kept vertical when it is in place, so that the jack and the pile axis are on the same vertical line. During the pile pressing construction process, the axial compression should be maintained at all times. If there is any deviation, it should be adjusted in time; an electric jack is used for pile pressing. The pile pressing construction should be carried out symmetrically to prevent uneven foundation stress. When pressing the pile, the jack must be kept perpendicular to the pile section axis, and a steel plate cushion block should be set between the jack and the pile top. The pile section is a steel pipe pile with a diameter of 273×10, and the pile section length is 2m - 3m. The pile joints adopt welded pile joints. When connecting the upper and lower piles, the upper and lower pile faces must be aligned to prevent pile face misalignment. When connecting the piles, the axes of the upper and lower piles should be kept consistent, and the pile connection time should be shortened as much as possible. It is required that the preparatory work is sufficient and the process cooperation is close; when connecting the piles, the upper and lower sections should be aligned to ensure uniform stress on the joint contact surface; a ϕ250*6 inner steel casing is arranged inside the steel pipe column at the pile joint.

[0015] During pile pressing, it is not advisable to stop midway. Otherwise, due to the overly long intermittent time, the pile pressing resistance will increase, making construction difficult. The pile pressing force should reach the designed final pile pressing force. Attention should be paid to the maintenance of instruments such as pressure gauges, and they should be repaired in a timely manner and calibrated regularly to reduce measurement errors. The construction standard of pile pressing is controlled by both the designed final pile pressing force and the pile penetration depth. In case of abnormal situations, relevant parties should be consulted to clarify the reasons and handle them properly. After pile pressing is completed, first insert a grouting pipe with a diameter of ϕ30 into the steel pipe pile, and fill it with sand and gravel. The filling height of the sand and gravel is 2.0m. After the filling of the sand and gravel is completed, pour C30 concrete into the steel pipe and vibrate it thoroughly. Pressure grouting is carried out again after 2 days, and the grouting pressure is 0.3MPa. The mixing ratio of the grouting liquid is: 42.5 ordinary Portland cement: water glass: special admixture = 100:3:0.2; S5. When the pile reaches the designed final pile pressing force, maintain a certain pressing stress for pile sealing and pour KL-40 material. Step S5 includes the following steps: S51. When the pile reaches the designed final pile pressing force, maintain a certain pressing stress for pile sealing and pour KL-40 material. After the pile sealing material meets the strength requirements, remove the bearing equipment. If the pile top does not reach the designed position, the exposed pile head must be cut off; S52. Cleaning of the pile pressing hole: Clean up the sundries, soil, and the original formwork in the pile pressing hole; S53. Chiseling the inverted bell mouth at the pile opening: To ensure the punching shear effect of the connection surface between the pile sealing concrete and the original pile cap, chisel the 300mm hole range of the pile hole into an inverted bell mouth with a smaller upper part and a larger lower part according to the design requirements. The bottom opening of the chiseled surface is about 40 - 60mm wider than the top opening on each side; S54. Installation of the pile sealing reaction frame and jack: After the chiseling of the pile sealing hole is completed, clean the hole. Install a small pile pressing reaction frame for pile sealing on the original pile pressing embedded screw with a connector, and set a pile sealing steel pipe on the steel pipe pile. The pile sealing steel pipe uses 150*5 steel pipe. Set a jack between the pile sealing steel pipe and the reaction frame, and press the jack to the designed pile sealing force; S55. Pouring the slightly expanded KL-40 pile sealing concrete: After the pile sealing pressure of the steel pipe pile reaches the designed value, wet the pile sealing hole with water, and set a circle of 203 water-swelling waterproof glue at the groove. Then use KL-40 high-strength non-shrinking material for pile sealing pouring, and the pouring surface is 150mm lower than the top of the pile cap; S56. Weld and restore the upper reinforcement of the original foundation slab at the pile top with the same specification. The welding requirements are determined according to the design drawing; S57. After the strength of the pile sealing concrete meets the design requirements, remove the pile sealing reaction frame and jack, clean the floating ash and impurities on the surface of the pile pressing anchor rod, restore the upper reinforcement, and formwork and pour concrete in this area for protection.

[0016] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation on the present invention itself. Various changes may be made in its form and details without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A permanent and temporary combined foundation reinforcement method, comprising the following steps: S1. Determine design parameters: Conduct field research on the site environment, identify the original building, and determine the parameters after structural analysis; S2, according to the parameters determined in step S2, line laying and checking, water drilling positioning, excavation of pile holes, hole reinforcement, water drilling cutting, and edge cleaning are carried out on site; S3. According to the pile hole positions determined in step S2, 12 M32 anchor rods are arranged near each pile hole, with an anchoring length of 500 mm and KL-80 cementitious material: S4, installing the pile press frame according to the anchor position in step 3; S5. When the pile is pressed to the designed final pressure, a certain compressive stress is maintained to seal the pile and pour KL-40 material.

2. A permanent and temporary combined foundation reinforcement method according to claim 1, characterized in that: Step S2 includes the following steps: S21. Laying out and checking the lines: Use the ink fountain to lay out the water drill hole position line at the position where the pile needs to be pressed at the bottom plate of the foundation according to the requirements of the drawing, and check the position of the cutting hole line; S22, Water drill positioning: According to the position of the hole line, use anchor rods to fix the drill on the surface of the concrete outside the cutting hole line; S23. Opening reinforcement: reinforce the edges of newly opened openings according to the requirements of the construction drawings; S24, water drill cutting: connect the water drill power supply, place the water drill bit on the inner side of the cutting hole line, and drill and cut along the line side by side; S25. Edge cleaning: Use an electric hammer to remove excess concrete inside the cutting line of the hole.

3. A permanent and temporary combined foundation reinforcement method according to claim 2, characterized in that: Step S3 includes the following steps: S31. Laying out and positioning: Mark the location and model of the drilling holes for embedding reinforcement according to the design requirements; S32. Drilling: Drilling should be done with a water drill. If the steel bars cannot be cut, the hole position should be adjusted to avoid them. For high-efficiency structural adhesives or KL-80 cementitious materials, the drilling diameter is d+4~8mm, and the anchoring length is 20d / 10d. The hole wall should be kept dry. S33, hole cleaning: After drilling, use compressed air to blow out the dust in the hole, then use a brush to clean the hole wall, and then check the hole depth and hole diameter. After processing, plug the hole with silk cotton to keep the hole dry; S34, steel bar rust removal: the rust within the anchorage length of the steel bar should be removed and polished to bring out the metallic luster; the anchorage length of the planted steel bar is 22d, the reserved length should be able to meet the lap length required by the design, and the adjacent two bars should be staggered by 35d; After the steel bar is processed, it should be rust-free. For ordinary steel bars without serious corrosion, the floating rust on the embedded part should be cleaned with a wire brush. Severely rusted steel bars cannot be used as embedded steel bars. If the steel bars are stained with oil, they should be cleaned with acetone. S35, Adhesive preparation: Structural adhesive is composed of two components, A and B. Take a clean container and weighing scale to mix according to the mixing ratio in the instructions, and stir with a stirrer for about 5-10 minutes until the color is uniform; S36, rebar planting: pinch the prepared anchoring glue into strips and put them into the hole. If the hole is deep, use thin steel bars to lightly tamp it. The amount of anchoring glue should be such that a small amount of material overflows after the steel bar is inserted. Insert the steel bar that has been rust-removed into the hole filled with structural glue, rotate the steel bar, insert and pull it out repeatedly, and stir the dust remaining on the hole wall into the structural glue until the surface of the structural glue attached to the steel bar is free of dust. Straighten and fix the steel bar; S37, curing and protection: Structural adhesive can be cured well at room temperature and low temperature. If the curing temperature is around 25℃, it can be used under load in 48 hours; if the curing temperature is around 5℃, it can be used under load in 72 hours; the steel bars should not be disturbed within 12 hours after planting, and if there is a major disturbance, the steel bars should be re-planted; S38. Determine the time for rebar planting: The entire process from mixing the glue to rebar planting is completed within 30 minutes. The next process can be carried out 24 hours after the rebar planting is completed. The initial setting time of the glue can be controlled by increasing or decreasing the amount of material B (curing agent); S39. Inspection: Use jack, anchor and reaction frame system to conduct pull-out test.

4. A permanent and temporary combined foundation reinforcement method according to claim 3, characterized in that: In step S4, before the pile driving construction, the geological conditions of the soil layer on site should be clearly understood, the pile driving frame should be kept vertical, the nuts of the anchor bolts should be tightened evenly, the pile section should be kept vertical in place, so that the jack and the pile axis are kept on the same vertical line, and the axis should be kept under pressure at any time during the pile driving construction. An electric jack is used for pile driving, and the pile driving construction should be carried out symmetrically to prevent the foundation from being unbalanced. When the pile is driven, the jack must be kept vertical to the axis of the pile section, and a steel plate pad should be set between the jack and the pile top. The pile joints are welded. When the upper and lower piles are connected, the upper and lower pile surfaces must be aligned. When connecting the piles, the axes of the upper and lower piles should be consistent to shorten the pile connection time. When connecting the piles, the upper and lower sections should be aligned to ensure that the contact surface of the joint is evenly stressed; a φ250*6 lined steel casing is set inside the steel pipe column at the pile connection.

5. A permanent and temporary combined foundation reinforcement method according to claim 4, characterized in that: Step S5 includes the following steps: S51. When the pile is pressed to the designed final pressure, a certain pressure stress is maintained to seal the pile, and KL-40 material is poured. When the pile sealing material meets the strength requirements, the bearing equipment is removed. If the pile top is not pressed to the designed position, the exposed pile head must be cut off; S52, pile hole cleaning: clean up the debris, soil and template in the original pile hole; S53. Chiseling of the inverted trumpet mouth of the pile mouth: To ensure the anti-shearing effect of the connection surface between the pile sealing concrete and the original cap, the 300mm hole of the pile hole is chiseled into an inverted trumpet mouth with a small top and a large bottom according to the design requirements. The hole at the bottom of the chiseled surface is about 40~60mm wider than the hole at the top on each side; S54, Installation of pile sealing reaction frame and jack: After the pile sealing hole is chiseled and cleaned, a small pile sealing reaction frame is installed on the original pile pressing pre-buried screw rod using a connector, and a pile sealing steel pipe is installed on the steel pipe pile. The pile sealing steel pipe is a 150*5 steel pipe. A jack is installed between the pile sealing steel pipe and the reaction frame, and the jack is pressed to the designed pile sealing force; S55. Casting of micro-expansion KL-40 pile sealing concrete: After the steel pipe pile sealing pressure reaches the design value, water the pile sealing hole to moisten it, and set a circle of 203 water-expandable waterproof glue in the groove, and then use KL-40 high-strength non-shrinkage material to cast the pile sealing, and the casting surface is 150mm lower than the top of the cap; S56. The reinforcement of the original foundation bottom plate at the top of the pile is welded back to the same specifications. The welding requirements are determined according to the design drawings. S57. After the concrete strength of the piles meets the design requirements, remove the pile reaction frame and jack, clean the dust and impurities on the surface of the press-fit anchor rods, restore the upper steel bars, and cast concrete in the area for protection.

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