Soft soil area real core prefabricated square pile deviation correction construction method and deviation correction reinforcement treatment method

Abstract

The application discloses a soft soil area real core prefabricated square pile deviation rectification construction method and deviation rectification reinforcement treatment method, and belongs to the field of building construction. The application utilizes a deviation rectification sleeve to screw around the deviated square pile, utilizes an in-situ deviation rectification method to pull the deviation rectification sleeve to realize deviation rectification of the deviated square pile, and removes the deviation rectification sleeve after the deviation rectification is completed; on the basis, the prefabricated square pile can be further expanded and reinforced. The deviation rectification capacity is reliable, the reinforcement capacity is remarkable, the bearing capacity improvement effect is obvious; is not limited by materials, and the required materials are common steel product pile materials and concrete in the market; the steel sleeve can be effectively recycled and secondarily reused; the construction is performed by using a screwing deviation rectification reinforcement equipment, all the construction can be completed by the mechanical equipment, and no new mechanical equipment is needed; the construction speed is fast, the work efficiency is high; the cost is low, the construction is quiet, and the environment is protected; meanwhile, the deviation rectification and reinforcement of the deviated pile can be accurately guided according to the actual situation on the site, and the guidance and operability are strong.

Description

Technical Field

[0001] This invention relates to a method for correcting and reinforcing engineering piles, and more specifically, to a method for correcting and reinforcing solid precast square piles in soft soil areas. Background Technology

[0002] With the rapid pace of urbanization in my country, cities are expanding outwards, leading to increasingly complex geological conditions in engineering construction. Different types of harsh geological conditions and diverse building load requirements pose growing challenges to project construction, especially for concealed works such as pile foundation construction, where the quality requirements are becoming increasingly stringent. For conventional engineering construction, commonly used pile types include bored piles, precast hollow pipe piles, and precast solid square piles. In areas with relatively good soil conditions, the construction quality of these three types of piles is relatively controllable, and issues such as pile deviation, weld breakage, and pile breakage are generally rare. However, in sedimentary geological environments such as fluvial, marine, and lacustrine facies, long-term subsidence and deposition caused by crustal movements since the Quaternary period have resulted in a thick layer of silty soft soil in the shallow layers. This soil layer has poor properties and is essentially in a fluid plastic state. During the construction of piles (especially precast piles), adverse conditions such as pile deviation, weld breakage, and pile breakage are prone to occur, affecting the quality of the pile body. This can cause the actual bearing capacity of misaligned piles to fail to meet design requirements, resulting in quality problems. In response to this unfavorable situation, the main measures currently being taken are as follows:

[0003] (1) In-situ correction method

[0004] The in-situ correction method refers to using physical means to correct the skewed engineering pile to its original design position. Currently, it is basically done by binding steel wire ropes to the pile body or setting steel clips on the inner wall of the engineering pile to lock the engineering pile. At the same time, excavators or jacks are used to provide reaction force to gradually pull the engineering pile, and finally restore the skewed engineering pile to its original design position.

[0005] In-situ correction is widely used in practice, but this method has certain drawbacks:

[0006] ① The applicability is poor. The in-situ correction method uses only two methods for locking the pile body in engineering piles: binding steel wire rope and setting buckles on the inner wall. However, both of these methods have significant limitations and hidden dangers.

[0007] If steel wire ropes are used to fix the engineering piles, the fixation is only possible about 1 meter above the top of the pile, failing to provide effective protection for the lower pile body, especially the pile joint. This makes it easy to cause secondary damage to the engineering pile during the correction process, particularly at the weld seams of the pile joints. Welding is highly likely to occur during correction, resulting in the correction not only failing to improve the pile's bearing capacity but also causing further damage such as weld breakage and pile fracture. Furthermore, for the solid precast square piles described in this article, the pile body is a cube, and the weld seams at the pile joints are square, making welding inherently more difficult and ensuring weld quality is harder compared to circular piles. This leads to poor weld quality, and the aforementioned pulling method is even more likely to damage these weld seams, causing secondary damage such as weld breakage and pile detachment. This not only fails to achieve the purpose of correction and remediation but also results in unusable piles.

[0008] If the method of fixing the engineering pile by setting clips on the inner wall of the pile is adopted, this method can only be used for hollow precast pipe piles. It is not applicable to the solid precast square piles, which are the focus of this article. The method used is to set steel clips about 3-4m deep on the inner wall of the hollow pipe pile to fix the hollow pipe pile, and then provide reaction force output to the steel clips to drive the displacement of the engineering pile. This method does have a good fixing effect on the pile body, greatly protects the safety of the pile joint position, and can effectively correct the engineering pile. However, as mentioned above, this method is only suitable for precast piles with hollow inner walls and cannot meet the needs of other types of engineering piles, especially the solid precast square piles described in this article. Because its structure is solid and there is no hollow inner wall, it cannot be fixed by clips. Therefore, this method has a narrow applicability and is not suitable for the pile type described in this article.

[0009] ② The reliability is poor. At present, the correction mainly uses excavators or jacks to provide reaction force output. Both of these methods are relatively simple and crude. The output reaction force cannot be reliably controlled. During the correction process, the reaction force cannot be provided in a timely and quantitative manner. The inability to accurately control the output reaction force leads to the adverse situation of overcorrection after correction, which cannot reliably meet the purpose of improving the bearing capacity of the pile foundation.

[0010] In conclusion, for the solid precast square piles described in this paper, the in-situ correction method lacks an effective means to correct the deviation of skewed solid precast square piles. However, solid square piles have a wide range of applications in actual engineering construction, and the prevalence of deviation in soft soil areas necessitates an urgent need for an effective correction method.

[0011] (2) Core reinforcement method

[0012] Core reinforcement refers to a method of reinforcing the pipe pile by lowering a steel cage to a certain depth inside the hollow precast pipe pile wall and then pouring concrete to reinforce the pipe pile. This method has a narrow applicability because it requires lowering the steel cage inside the pile foundation wall, which is not feasible for solid precast piles. Therefore, it is often used in projects using hollow precast pipe piles and is not suitable for the solid precast square piles discussed in this article.

[0013] (3) Replacement method

[0014] Replacing a faulty pile with a new pile driven near the original faulty pile location. The pile types that can be used for this method include precast piles and cast-in-place piles, but in soft soil areas, bored cast-in-place piles are conventionally chosen. This is because the presence of a faulty pile can only be determined after the foundation pit has been excavated to the bottom. If a replacement pile were to be driven at this point, large machinery would have to be lowered to the bottom of the pit. However, in soft soil areas, the soil properties are poor, and the bearing capacity is low, making it impossible for large machinery (such as static pressure pile drivers) to be driven into the pit. Furthermore, since some foundation pit support methods in soft soil areas often employ internal bracing, this restricts the vertical height of mechanical construction. Static pressure pile drivers are quite tall, and if internal bracing is present, there is no working surface for the machinery. Therefore, under these unfavorable conditions, only smaller and lighter bored cast-in-place pile drivers are chosen for the replacement pile. While the replacement pile method can solve the problem once and for all, it has the following drawbacks:

[0015] ① The construction cost is too high and the economic efficiency is poor. Due to the aforementioned reasons, if it is necessary to supplement the piles, the only option is to use bored cast-in-place piles. The cost of constructing a single bored cast-in-place pile, in terms of both construction and material costs, is far greater than that of a single precast pile, which greatly increases the construction cost.

[0016] ② The construction period is long and the delay is significant. Due to the aforementioned reasons, if it is necessary to supplement the piles, the only option is to use bored cast-in-place piles. The construction time for a single bored cast-in-place pile is much longer than that for a single precast pile. Furthermore, after the construction is completed, the bored cast-in-place piles still need to meet the curing time for the concrete and the time required for subsequent testing. Therefore, supplementing the piles often greatly extends the construction period, which has a significant impact on projects with tight schedules.

[0017] ③ There is an environmental pollution problem. Due to the aforementioned reasons, if we want to supplement the piles, we can only use bored cast-in-place piles for construction. However, bored cast-in-place piles use mud slurry wall protection technology, which requires the setting up of mud discharge pools and circulation pools on site, which is very detrimental to the on-site environmental protection.

[0018] ④ For multi-section precast piles, since the sections are primarily connected by welding, the quality of the welds directly determines the stability of the connection. Weld quality is significantly affected by site conditions and human factors during construction, often resulting in poor welding quality. This becomes a weak point in multi-section precast piles, especially in projects using multi-section precast solid square piles, where the square shape further complicates welding quality. Therefore, in soft soil areas, weld breaks frequently occur at the weld joints of precast solid square piles. This leads to significant displacement of the upper pile sections, rendering them defective and failing to meet design requirements, while the lower pile sections remain largely intact and meet design requirements. Simply using supplementary piles often wastes the lower, healthy pile sections, resulting in substantial waste of construction costs.

[0019] ⑤ There are no replacement piles available on site. The main building area has a dense network of engineering piles. If a bad pile needs to be replaced, there are often no replacement piles available around the bad pile, making it impossible to carry out construction. Summary of the Invention

[0020] 1. The technical problem that the invention aims to solve

[0021] The primary objective of this invention is to overcome the shortcomings of existing solid precast square piles in soft soil areas, which lack reliable and safe methods for correcting deviations. This invention provides a method for correcting deviations in solid precast square piles in soft soil areas. The technical solution of this invention utilizes a correction sleeve to tighten and secure the misaligned square pile, and then uses an in-situ correction method to pull the correction sleeve to correct the deviation. After correction is completed, the correction sleeve is removed. This method offers advantages such as safety and reliability, rapid construction efficiency, freedom of construction angle, simple and effective operation, strong applicability, no secondary damage, and recyclability and environmental friendliness.

[0022] The second objective of this invention is to provide a construction method for correcting and reinforcing solid precast square piles in soft soil areas. This method addresses the problem that existing methods can only address the issue of weld defects at pile joints by drilling and grouting piles. By using a correction sleeve to create a grouting and diameter-expanding space around the corrected pile body, and then placing a ring-shaped steel cage around the pile body and pouring concrete, the bearing capacity of the damaged pile can be effectively improved. This method has the advantages of being safe, controllable, environmentally friendly, and effective. At the same time, it effectively utilizes the good piles in the lower part of the multi-section pile, reinforcing only the upper damaged piles, thus saving costs and construction time to the greatest extent possible.

[0023] The third objective of this invention is to further enhance the bearing capacity of solid precast square piles. A large casing is used for correction, and a grouting and expansion space is formed around the pile body after correction. Small casings and a ring-shaped reinforcing cage are placed within this space, and concrete is poured using the remaining small casings and the ring-shaped reinforcing cage for expansion and reinforcement. This effectively enhances the bearing capacity of the precast square piles, is highly practical, and solves the problems of long construction periods, high costs, limited construction space, and certain pollution associated with existing bored pile reinforcement methods.

[0024] 2. Technical Solution

[0025] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0026] The present invention provides a method for correcting the deviation of solid precast square piles in soft soil areas, comprising the following process steps:

[0027] S1. Excavate part of the surface soil at the pile head of the misaligned square pile to expose the pile top. Use a screwing and straightening reinforcement device to screw the straightening sleeve to the joint position of the misaligned square pile and fix it so that the straightening sleeve is fitted on the outside of the misaligned square pile, and a gap T1 is left between the straightening sleeve and the misaligned square pile. The lower end of the straightening sleeve extends to D1 below the joint position of the misaligned square pile.

[0028] S2. A sling is used to connect the correction sleeve at the head of the misaligned square pile, and the sling is connected to the correction traction device through a traction rope.

[0029] S3. Use a correction traction device to pull the correction sleeve until the correction sleeve, along with the misaligned square pile, returns to the original design pile position.

[0030] S4. After the offset square pile is restored to its original design position, the verticality of the square pile is checked using testing tools. Once the requirements are met, the correction is stopped.

[0031] S5. Fill the remaining gaps on the outside of the correction sleeve in step S3 with fluidized solidified soil to fix the pile body;

[0032] S6. After the fluidized solidified soil has self-compacted, remove the sling and then use the screw-tightening reinforcement equipment to remove the correction sleeve.

[0033] S7. After correction, the pile head is backfilled with cohesive soil to restore it;

[0034] S8. Inspect and verify the quality and bearing capacity of the pile body after correction.

[0035] Furthermore, if it is necessary to correct and reinforce the solid precast square piles, then:

[0036] A. In step S1, a gap T2 is left between the correction sleeve and the misaligned square pile. The lower end of the correction sleeve extends to D2 below the pile connection position of the misaligned square pile, where T2 > T1 and D2 > D1.

[0037] B. Replace steps S5 and S6 with a concrete enlargement reinforcement step, the specific steps are as follows:

[0038] After step S4 is completed, disconnect the connection between the screwing and straightening reinforcement equipment and the straightening sleeve, and remove the sling on the straightening sleeve. Re-fix the straightened pile body with the sling and use the sling to flush out the soil inside the straightening sleeve to ensure that the ring steel cage can be lowered smoothly.

[0039] T2. Place a ring-shaped steel cage between the correction sleeve and the corrected engineering pile;

[0040] T3. After the ring-shaped steel cage is lowered, pour concrete between the correction sleeve and the corrected engineering pile.

[0041] T4. After the concrete has initially set, untie the slings and simultaneously remove the correction sleeves using a rotary correction and reinforcement device.

[0042] Furthermore, if further correction and reinforcement of the solid precast square piles are required, then:

[0043] A. Replace the correction sleeve in step S1 with a large sleeve. Use a screw-tightening and reinforcement device to screw the large sleeve to the joint position of the misaligned square pile and fix it, so that the large sleeve is fitted on the outside of the misaligned square pile, and a gap T3 is left between the large sleeve and the misaligned square pile. The lower end of the large sleeve extends to D3 below the joint position of the misaligned square pile, where T3 > T1 and D3 > D1. In steps S2 and S3, use the large sleeve to restore the misaligned square pile to the original designed pile position.

[0044] B. Replace steps S5 and S6 with the casing-concrete composite diameter expansion reinforcement step. The specific steps are as follows:

[0045] After step S4 is completed, disconnect the connection between the screwing and straightening reinforcement equipment and the large casing, and remove the sling on the large casing. Re-fix the pile body after straightening using the sling. At the same time, use a high-pressure jet pipe to flush out the soil inside the large casing to ensure that the small casing can be lowered smoothly.

[0046] T2. Use a screwing and straightening reinforcement device to screw the small sleeve to the pile connection position of the straightened engineering pile and fix it so that the small sleeve is fitted on the outside of the straightened engineering pile and a gap is left between the small sleeve and the straightened engineering pile. T4.

[0047] T3. After the small sleeve is installed and fixed in the predetermined position, disconnect the connection between the screwing and straightening reinforcement equipment and the small sleeve, and lower the ring steel cage between the small sleeve and the straightened engineering pile.

[0048] T4. After the ring-shaped steel cage is lowered, pour concrete between the small sleeve and the corrected engineering pile.

[0049] T5. After the concrete reaches its strength, backfill the large and small casing trenches with fluidized solidified soil.

[0050] T6. After the fluidized solidified soil has self-compacted, remove the sleeve and then use a rotary correction and reinforcement device to remove the large sleeve, while leaving the small sleeve intact.

[0051] Furthermore, the correction sleeve is a circular steel pipe.

[0052] Furthermore, both the large and small sleeves are circular steel pipes.

[0053] Furthermore, the top of the annular steel cage is pre-reserved with steel bars for later anchoring into the foundation.

[0054] Furthermore, during the tightening and lowering of the correction sleeve or large sleeve, the soil plug effect is used to fill the splice position of the misaligned square pile with the original soil to protect the weld at the splice.

[0055] Furthermore, the rotary straightening and reinforcement equipment has a rotary power head that moves up and down and adjusts the angle under the control of the rotary straightening and reinforcement equipment. The rotary power head includes a rotary fixing device, a hydraulic motor, a flange connector and a sleeve fixing device arranged sequentially from top to bottom. The sleeve fixing device is driven by the hydraulic motor to rotate forward or in reverse.

[0056] Furthermore, the correction traction device is installed on the screwing correction and reinforcement equipment, and the correction traction device is connected to the sling via a traction rope.

[0057] The present invention discloses a method for correcting and reinforcing solid precast square piles in soft soil areas, and the on-site treatment process is as follows:

[0058] A. If a solid precast square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient after testing, but no weld breakage or pile breakage is observed, the aforementioned method for correcting the misalignment of solid precast square piles in soft soil areas shall be used to correct the misalignment of the precast square piles. The piles shall then be retested. If the bearing capacity meets the requirements, the acceptance test is passed. If the bearing capacity does not meet the requirements, the aforementioned method for correcting the misalignment of solid precast square piles in soft soil areas shall be used to further enlarge and reinforce the precast square piles. After reinforcement, the piles shall be retested. If the bearing capacity meets the requirements, the acceptance test is passed. If the bearing capacity still does not meet the requirements, then the use of bored cast-in-place piles for supplementary piles shall be considered.

[0059] B. If a solid precast square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient after testing, and weld cracking occurs, but no pile breakage occurs, then the above-mentioned construction method for correcting the misalignment of solid precast square piles in soft soil areas shall be used to correct the misalignment and enlarge the diameter of the precast square piles for reinforcement; and the bearing capacity shall be retested. If the bearing capacity meets the requirements, the acceptance shall be passed; if the bearing capacity still does not meet the requirements after testing, then the use of bored cast-in-place piles for supplementary piles shall be considered.

[0060] C. If a precast solid square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient, or if there are weld cracks or broken piles, then bored cast-in-place piles should be used to supplement the piles. The bearing capacity should be tested again. If the bearing capacity meets the requirements, the acceptance will be passed. If the bearing capacity does not meet the requirements, then it will be considered to continue to supplement the piles.

[0061] 3. Beneficial effects

[0062] Compared with existing known technologies, the technical solution provided by this invention has the following significant advantages:

[0063] (1) The present invention provides a method for correcting the deviation of solid precast square piles in soft soil areas and a method for correcting and reinforcing the deviation. The method involves using a correction sleeve to tighten and enclose the deviated square pile, and using an in-situ correction method to pull the correction sleeve to correct the deviation of the square pile. After the correction is completed, the correction sleeve is removed. On this basis, the precast square pile can be further enlarged and reinforced. The correction capability is effective and reliable. The reinforcement capability is significant and the effect on improving the bearing capacity is obvious. The bearing capacity can be further improved by leaving a steel pipe. It is not limited by materials. The required materials are all common steel products (steel pipe piles, steel bars) and concrete. The steel sleeve can be effectively recycled and reused. It is basically 100% fully recyclable. The correction and reinforcement equipment is used for construction. All construction can be completed by this machine without the need for additional machinery. The construction speed is fast and the efficiency is high. The cost is low and the noise is quiet and environmentally friendly. According to the actual site conditions, it provides accurate guidance for the correction and reinforcement of the deviated pile. It has strong guidance and practicality.

[0064] (2) The present invention provides a method for correcting the deviation of solid precast square piles in soft soil areas and a method for correcting and reinforcing the deviation. It can effectively correct and reinforce the deviation and weld failure of solid square piles, and can significantly improve the bearing capacity of the pile foundation, save construction time and cost. It has strong applicability and advanced features, and has the value of wide-ranging promotion.

[0065] (3) The present invention provides a construction method for correcting the deviation of solid precast square piles in soft soil areas. It innovatively uses a sleeve to protect the weak welded parts of the deviated pile and then uses a wire rope to correct the deviation, which can safely and effectively correct the deviation of the solid square piles.

[0066] (4) The present invention provides a construction method for correcting the deviation of solid precast square piles in soft soil areas. It innovatively improves the bearing capacity of solid square piles by using a method of screwing in a sleeve for hole protection, effectively lowering the steel cage, and later pouring concrete to expand the diameter. For situations where it is necessary to further enhance the bearing capacity of in-situ solid square piles, the method of screwing in a double sleeve for hole protection, effectively lowering the steel cage, leaving an inner steel sleeve, and later pouring concrete to expand the diameter can meet the needs of further improving the bearing capacity and can be applied to more diverse and complex site conditions.

[0067] (5) The present invention provides a method for correcting the deviation of solid precast square piles in soft soil areas. It utilizes the soil plugging phenomenon caused by the twisting effect to effectively protect the welded pile joint position at the weak point. At the same time, the sleeve can be twisted and inserted or pulled out. The construction operation is simple and effective and has strong applicability.

[0068] (6) The present invention provides a method for correcting the deviation of solid precast square piles in soft soil areas. The materials required for construction are steel sleeves, steel bars, concrete, etc., which are readily available on the market. There are no special requirements, and the materials are easy to purchase and have strong applicability. The steel sleeve materials can be recycled and reused in the later stage, which is green and environmentally friendly and further reduces the construction cost.

[0069] (7) The present invention provides a method for correcting the deviation of solid precast square piles in soft soil areas. In cases where it is necessary to further enhance the bearing capacity of the in-situ solid square piles, the trench between the large and small casings is backfilled with fluidized solidified soil. By utilizing the self-compacting properties of fluidized solidified soil, the compactness of the trench after the outer large casing is removed is effectively ensured, thus guaranteeing the requirement to strengthen the side resistance of the pile body.

[0070] (8) The present invention provides a method for correcting the deviation of solid precast square piles in soft soil areas. The entire process only requires the use of a rotary correction and reinforcement device, without the need for other machinery. Moreover, the machinery has fast construction efficiency, simple operation, and strong applicability, and has the value of widespread promotion. Attached Figure Description

[0071] Figure 1(a) is a schematic diagram showing that the actual construction pile position is offset from the original design pile position to a certain extent (the weld is not open).

[0072] Figure 1(b) is a schematic diagram of the insertion of the correction sleeve using a screw-tightening correction reinforcement device during the correction process; in Figure 1(b), the AA section view shows the original soil at the pile splicing location, and the BB section view shows the relative position of the correction sleeve and the square pile.

[0073] Figure 1(c) is a schematic diagram of the connection between the correction sleeve and the sling during the correction process; the AA cross-sectional view in Figure 1(c) shows the position of the sling on the correction sleeve;

[0074] Figure 1(d) is a schematic diagram of the state of pulling the correction sleeve using the correction traction device during the correction process;

[0075] Figure 1(e) is a schematic diagram of using a correction traction device to pull the square pile to the original design pile position during the correction process;

[0076] Figure 1(f) is a schematic diagram of the state of filling the remaining voids with fluidized solidified soil during the correction process;

[0077] Figure 1(g) is a schematic diagram of pulling out the correction sleeve using a screw-tightening correction and reinforcement device during the correction process;

[0078] Figure 1(h) is a schematic diagram of backfilling cohesive soil at the pile head after correction during the correction process.

[0079] Figure 1(i) is a schematic diagram of the quality and bearing capacity of the square pile body after correction;

[0080] Figure 2(a) is a schematic diagram showing that the actual construction pile position is offset from the original design pile position to a certain extent (weld opening);

[0081] Figure 2(b) is a schematic diagram of the insertion of the correction sleeve using the rotary correction reinforcement equipment during the correction reinforcement process; in Figure 2(b), the AA section view shows the original soil at the pile splicing location, and the BB section view shows the relative position of the correction sleeve and the square pile.

[0082] Figure 2(c) is a schematic diagram of the connection between the correction sleeve and the cable during the correction and reinforcement process; in Figure 2(c), the AA section view shows the position of the cable on the correction sleeve; the BB section view shows the relative position of the correction sleeve and the square pile.

[0083] Figure 2(d) is a schematic diagram of the state of pulling the correction sleeve using the correction traction device during the correction and reinforcement process;

[0084] Figure 2(e) is a schematic diagram of using a correction traction device to pull the square pile to the original design pile position during the correction and reinforcement process;

[0085] Figure 2(f) is a schematic diagram of using a high-pressure jet pipe to flush the soil inside the casing during the correction and reinforcement process; in Figure 2(f), the AA section view shows the relative positions of the square pile, the cable and the correction casing; the BB section view shows the relative position of the high-pressure jet pipe inside the correction casing.

[0086] Figure 2(g) is a schematic diagram of the lowering of the annular steel cage during the correction and reinforcement process; in Figure 2(g), the AA section view shows the relative positions of the square pile, the cable, the correction sleeve and the annular steel cage; the BB section view shows the relative position of the annular steel cage inside the correction sleeve.

[0087] Figure 2(h) is a schematic diagram of concrete pouring during the correction and reinforcement process;

[0088] Figure 2(i) is a schematic diagram of pulling out the correction sleeve using a screw-tightening correction and reinforcement device during the correction and reinforcement process;

[0089] Figure 2(j) is a schematic diagram of backfilling cohesive soil at the pile head behind the correction point during the correction and reinforcement process.

[0090] Figure 2(k) is a schematic diagram of the test results of the square pile body quality and bearing capacity after the correction and reinforcement.

[0091] Figure 3(a) is a schematic diagram showing that the actual construction pile position is offset from the original design pile position to a certain extent (weld opening);

[0092] Figure 3(b) is a schematic diagram of the large casing being inserted using a rotary correction and reinforcement device during the correction and reinforcement process; in Figure 3(b), the AA section view shows the original soil at the pile splice location, and the BB section view shows the relative position of the large casing and the square pile.

[0093] Figure 3(c) is a schematic diagram of the connection between the large casing and the cable during the correction and reinforcement process; in Figure 3(c), the AA section view shows the position of the cable on the large casing; the BB section view shows the relative position of the large casing and the square pile.

[0094] Figure 3(d) is a schematic diagram of the state of the large sleeve being pulled by the correction traction device during the correction and reinforcement process;

[0095] Figure 3(e) is a schematic diagram of using a correction traction device to pull the square pile to the original design pile position during the correction and reinforcement process;

[0096] Figure 3(f) is a schematic diagram of using a high-pressure jet pipe to flush the soil inside the casing during the correction and reinforcement process; in Figure 3(f), the AA section view shows the relative positions of the square pile, the cable and the large casing; the BB section view shows the relative position of the high-pressure jet pipe inside the correction casing.

[0097] Figure 3(g) is a schematic diagram of the lowering of the small casing during the correction and reinforcement process; in Figure 3(g), the AA section view shows the relative positions of the square pile, the cable, and the large and small casings; the BB section view shows the relative positions of the large and small casings.

[0098] Figure 3(h) is a schematic diagram of the lowering of the annular steel cage during the correction and reinforcement process; in Figure 3(h), the AA section view shows the relative positions of the square pile, the cable, the large and small casings and the annular steel cage; the BB section view shows the relative position of the annular steel cage inside the casing.

[0099] Figure 3(i) is a schematic diagram of concrete pouring during the correction and reinforcement process;

[0100] Figure 3(j) is a schematic diagram of backfilling fluidized solidified soil between the large and small casings during the correction and reinforcement process; in Figure 3(j), the AA cross-sectional view shows the relative positions of the square pile, the cable, the large and small casings, the concrete and the fluidized solidified soil; the BB cross-sectional view shows the relative positions of the concrete and the fluidized solidified soil inside the large and small casings.

[0101] Figure 3(k) is a schematic diagram of the large sleeve being pulled out using a rotary straightening and reinforcement device during the straightening and reinforcement process; the AA cross-sectional view in Figure 3(k) shows the relative position after the large sleeve is ready to be pulled out.

[0102] Figure 3(l) is a schematic diagram of backfilling cohesive soil at the pile head behind the correction point during the reinforcement process; the AA section view in Figure 3(l) shows the relative position after the removal of the large casing.

[0103] Figure 3(m) is a schematic diagram of the test results of the square pile body quality and bearing capacity after the correction and reinforcement;

[0104] Figure 4 This is a schematic diagram of the screw-tightening and straightening reinforcement device in this invention;

[0105] Figure 5 This is a schematic diagram of the screwing power head in this invention;

[0106] Figure 6 This is a schematic diagram of the connection and transmission structure between the correction traction device and the lasso in this invention;

[0107] Figure 7 This is a flowchart of the method for correcting and reinforcing solid precast square piles in soft soil areas according to the present invention.

[0108] Explanation of the labels in the diagram:

[0109] 1. Tightening and straightening reinforcement equipment; 2. Tightening power head; 2-1. Rotary fixing device; 2-2. Hydraulic motor; 2-3. Flange connector; 2-4. Sleeve fixing device; 3. Straightening sleeve; 3-1. Large sleeve; 3-2. Small sleeve; 4. Straightening traction device; 5. Traction rope; 5-1. Buckle; 6. Sling; 7. High-pressure jet pipe; 8. Ring-shaped steel cage. Detailed Implementation

[0110] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings.

[0111] To address the problem of insufficient bearing capacity of solid square piles in soft soil areas due to misalignment and weld defects, this invention proposes a comprehensive process-oriented treatment technology with correction and reinforcement as its core methods. It primarily utilizes an improved fully automated hydraulic rotary correction and reinforcement device and method to correct and reinforce misaligned or welded precast square piles, thereby significantly improving the pile foundation's bearing capacity. This technology can conveniently, effectively, controllably, and safely increase the bearing capacity of misaligned piles, while also significantly saving construction time and costs. Employing an innovative in-situ damaged pile correction and reinforcement technology, this invention not only corrects and reinforces misaligned square piles but also further enhances the overall pile foundation's bearing capacity through the installation of steel sleeves and concrete pouring, making it applicable to more diverse and complex site conditions.

[0112] First, to address the lack of a reliable and safe method for correcting the deviation of solid precast square piles in soft soil areas, a new method for correcting the deviation of solid precast square piles is proposed. This method has advantages such as safety and reliability, fast construction efficiency, free construction angle, no secondary damage, and recyclability and environmental friendliness. Figures 1(a) to 1(i) The construction process of the solid precast square pile correction method in soft soil areas according to the present invention is shown. Figure 1(a) is a schematic diagram showing that the actual construction pile position of the upper engineering pile has deviated from the original design pile position. After testing, the bearing capacity of the deviated square pile is insufficient, but there is no weld breakage or pile breakage. At this time, the solid square pile correction method is considered. Combined with Figures 1(b) to 1(i) As shown, the specific process steps include the following:

[0113] S1. As shown in Figure 1(b), firstly, part of the surface soil at the head of the misaligned square pile is excavated to expose the top of the pile. The correction sleeve 3 is screwed to the joint position of the misaligned square pile using the screwing correction and reinforcement device 1, so that the correction sleeve 3 is fitted on the outside of the misaligned square pile, and a gap T1 is left between the correction sleeve 3 and the misaligned square pile. The lower end of the correction sleeve 3 extends to D1 below the joint position of the misaligned square pile. The correction sleeve 3 extends into the head of the lower engineering pile. At the same time, during the screwing and lowering process of the correction sleeve 3, the joint position of the misaligned square pile is filled with the original soil by the soil plug effect to protect the weld at the joint. This step can be carried by the screwing correction and reinforcement device 1 to drive the correction sleeve 3 to rotate clockwise, making the correction sleeve 3 easier to insert.

[0114] S2. As shown in Figure 1(c), a sling 6 is used to connect the correction sleeve 3 at the head of the misaligned square pile. The sling 6 is connected to the correction traction device 4 through the traction rope 5.

[0115] S3. As shown in Figure 1(d), the correction traction device 4 is used to pull the correction sleeve 3 until the correction sleeve 3 brings the deviated square pile back to the original design pile position. During this process, the weak welded parts of the deviated square pile are protected by the correction sleeve 3, and the correction is safe and reliable.

[0116] S4. As shown in Figure 1(e), after the offset square pile is restored to the original design pile position, the verticality of the square pile is checked with a testing tool. Once the requirements are met, the correction is stopped. At this time, a residual gap is formed on one side of the correction sleeve 3.

[0117] S5. As shown in Figure 1(f), the remaining gaps generated on the outside of the correction sleeve 3 in step S3 are filled with fluidized solidified soil to fix the pile body.

[0118] S6. As shown in Figure 1(g), after the fluidized solidified soil has self-compacted, release the sling 6, and then use the rotary correction and reinforcement device 1 to pull out the correction sleeve 3. During this process, the rotary correction and reinforcement device 1 can be used to drive the correction sleeve 3 to reverse, making it easier to pull out the correction sleeve 3.

[0119] S7. As shown in Figure 1(h), cohesive soil is used to backfill and restore the pile head after the correction.

[0120] S8. As shown in Figure 1(g), the quality and bearing capacity of the pile body after correction are tested and verified. This testing process can use existing testing methods such as small strain and static load.

[0121] Secondly, regarding the problem of solid square piles in soft soil areas suffering significant losses in bearing capacity due to welding failure, thus failing to meet design requirements, the current only solution is to drill and grout piles. This approach is limited, and its economic efficiency and construction period are significantly affected. Therefore, in view of this situation, a new reinforcement method for solid precast square piles is proposed. This method can effectively improve the bearing capacity of damaged piles and has the advantages of safety, controllability, environmental friendliness, and effectiveness. At the same time, it effectively utilizes the good piles in the lower part of the multi-section pile, reinforcing only the upper damaged piles, thus saving costs and construction time to the greatest extent possible. Figures 2(a) to 2(k) The construction process of the solid precast square pile correction method in soft soil areas according to the present invention is shown. Based on the aforementioned correction method, it achieves diameter expansion and reinforcement by pouring concrete. Figure 2(a) is a schematic diagram showing that the actual construction pile position of the upper engineering pile deviated from the original design pile position. Testing revealed that the deviated square pile had insufficient bearing capacity and weld cracking, but no pile breakage occurred. In this case, the solid square pile correction and diameter expansion reinforcement method is considered. That is, if it is necessary to correct and reinforce the solid precast square pile based on the aforementioned correction method, then:

[0122] A. As Figures 2(b) to 2(d)As shown, in step S1, a gap T2 is left between the corrective sleeve 3 and the misaligned square pile. The lower end of the corrective sleeve 3 extends to a point D2 below the splice position of the misaligned square pile, where T2 > T1 and D2 > D1. The gap T2 should meet the dimensions of the lowered annular steel cage 8. Due to the increase in gap T2, the dimension D2 of the corrective sleeve 3 extending into the pile head of the lower engineering pile also needs to be appropriately increased. Simultaneously, during the tightening and lowering of the corrective sleeve 3, the splice position of the misaligned square pile is filled with undisturbed soil using the soil plug effect to protect the weld at the splice. The steps for correcting the misalignment of the square pile using this corrective sleeve 3 are the same as steps S2 to S4 above (see details). Figures 2(c) to 2(e) ).

[0123] B. Replace steps S5 and S6 with a concrete enlargement reinforcement step, the specific steps are as follows:

[0124] T1. As shown in Figure 2(f), after step S4 is completed, disconnect the connection between the screwing and straightening reinforcement device 1 and the straightening sleeve 3, and release the sling 6 on the straightening sleeve 3. Re-fix the straightened pile body with the sling 6. At the same time, use the high-pressure jet pipe 7 to flush out the soil on the inner wall of the straightening sleeve 3 to ensure that the ring steel cage 8 can be lowered smoothly.

[0125] T2. As shown in Figure 2(g), a ring-shaped steel cage 8 is placed between the correction sleeve 3 and the corrected engineering pile; the reinforcement of the ring-shaped steel cage 8 is determined according to the bearing capacity requirements.

[0126] T3. As shown in Figure 2(h), after the ring-shaped steel cage 8 is lowered, concrete is poured between the correction sleeve 3 and the corrected engineering pile; steel bars are reserved at the top of the ring-shaped steel cage 8 for later anchoring into the pile cap.

[0127] T4. As shown in Figure 2(i), after the concrete has initially set, the sling 6 is untied, and the correction sleeve 3 is removed using the screw-tightening and reinforcement device 1.

[0128] Referring to Figures 2(j) and 2(k), the backfilling of cohesive soil and the pile foundation testing steps are the same as steps S7 and S8 above.

[0129] Third, for existing solid square piles, there are currently no effective means to further increase their bearing capacity. The only option is to use bored piles for reinforcement, which are time-consuming, costly, have limited construction space, and are somewhat polluting. Therefore, a new method for reinforcing solid precast square piles is proposed, which can effectively further enhance the bearing capacity and is highly practical. Figures 3(a) to 3(m)The construction process of the solid precast square pile correction method in soft soil areas according to the present invention is shown. Based on the aforementioned correction method, it achieves further diameter expansion and reinforcement through concrete pouring and casing placement. Figure 3(a) is a schematic diagram showing that the actual construction pile position of the upper engineering pile deviated from the original design pile position. Testing revealed that the deviated square pile had insufficient bearing capacity and weld cracking, but no pile breakage. To further improve the pile foundation bearing capacity, a solid square pile reinforcement method can be considered. That is, if further correction and reinforcement of the solid precast square pile is required based on the aforementioned correction method, then:

[0130] A. As Figures 3(b) to 3(d) As shown, the correction sleeve 3 in step S1 is replaced with a large sleeve 3-1. The large sleeve 3-1 is first screwed to the joint position of the offset square pile using the screwing correction and reinforcement device 1, so that the large sleeve 3-1 is fitted on the outside of the offset square pile, and a gap T3 is left between the large sleeve 3-1 and the offset square pile. The lower end of the large sleeve 3-1 extends to D3 below the joint position of the offset square pile, where T3 > T1 and D3 > D1. In steps S2 and S3, the offset square pile is restored to the original design pile position using the large sleeve 3-1. The gap T3 should meet the size of the lowered small sleeve 3-2 and the ring steel cage 8. Due to the increase in gap T3, the size D3 of the large sleeve 3-1 extending into the pile head of the lower engineering pile also needs to be appropriately increased. At the same time, during the screwing down of the large sleeve 3-1, the joint position of the offset square pile is filled with the original soil using the soil plug effect to protect the weld at the joint. The steps for correcting the misalignment of the square pile using the large casing 3-1 are the same as steps S2 to S4 above (see details). Figures 3(c) to 3(e) ).

[0131] B. Replace steps S5 and S6 with the casing-concrete composite diameter expansion reinforcement step. The specific steps are as follows:

[0132] T1. As shown in Figure 3(f), after step S4 is completed, disconnect the connection between the screwing and straightening reinforcement device 1 and the large sleeve 3-1, and release the sling 6 on the large sleeve 3-1. Re-fix the pile body of the corrected engineering pile using the sling 6. At the same time, use the high-pressure jet pipe 7 to flush out the soil on the inner wall of the large sleeve 3-1 to ensure that the small sleeve 3-2 can be lowered smoothly.

[0133] T2. As shown in Figure 3(g), the small sleeve 3-2 is screwed to the pile connection position of the corrected engineering pile using the screwing and straightening reinforcement device 1, so that the small sleeve 3-2 is fitted on the outside of the corrected engineering pile, and a gap T4 is left between the small sleeve 3-2 and the corrected engineering pile; the size of the annular gap between the large sleeve 3-1 and the small sleeve 3-2 is Δd.

[0134] T3. As shown in Figure 3(h), after the small sleeve 3-2 is fixed in the predetermined position, disconnect the connection between the screwing and straightening reinforcement device 1 and the small sleeve 3-2, and lower the annular steel cage 8 between the small sleeve 3-2 and the straightened engineering pile; the reinforcement of the annular steel cage 8 is determined according to the bearing capacity requirements.

[0135] T4. As shown in Figure 3(i), after the ring-shaped steel cage 8 is lowered, concrete is poured between the small sleeve 3-2 and the corrected engineering pile; steel bars are reserved at the top of the ring-shaped steel cage 8 for later anchoring into the pile cap.

[0136] T5. As shown in Figure 3(j), after the concrete reaches its strength, backfill the large sleeve 3-1 and the small sleeve 3-2 with fluidized solidified soil.

[0137] T6. As shown in Figure 3(k), after the fluidized solidified soil has self-compacted, release the sleeve 6, and then use the rotary correction and reinforcement equipment 1 to remove the large sleeve 3-1, while leaving the small sleeve 3-2 intact.

[0138] Referring to Figures 3(l) and 3(m), the backfilling of cohesive soil and the pile foundation testing steps are the same as steps S7 and S8 above.

[0139] The aforementioned straightening sleeve 3, large sleeve 3-1, and small sleeve 3-2 are all circular steel pipes, making their insertion and removal easy and labor-saving through screwing. The circular steel pipes used are common and readily available steel pipe pile materials, offering strong overall applicability and freedom from material procurement limitations. Furthermore, except for the small sleeve 3-2 which can be retained for future use, both the straightening sleeve 3 and large sleeve 3-1 can be removed using the screwing and straightening reinforcement device 1, allowing for secondary recycling of the steel pipe piles. This significantly saves on materials and costs, and promotes green and environmentally friendly construction.

[0140] Figure 4 and Figure 5The present invention illustrates a rotary alignment and reinforcement device. This device 1 has a rotary power head 2 that moves vertically and adjusts in angle under its control. Alignment sleeves 3, large sleeves 3-1, or small sleeves 3-2 are mounted on the rotary power head 2, which drives the corresponding sleeves to be inserted or removed. The rotary alignment and reinforcement device 1 can be modified from an existing excavator by replacing the excavator's bucket with the rotary power head 2. The rotary power head 2 includes, from top to bottom, a rotary retainer 2-1, a hydraulic motor 2-2, a flange connector 2-3, and a sleeve retainer 2-4. The sleeve retainer 2-4 is driven by the hydraulic motor 2-2 to rotate forward or reverse. The rotating fixing device 2-1 is used to connect the hydraulic motor 2-2 and the folding arm of the rotating correction and reinforcement device 1. The flange connector 2-3 is used to connect the output head of the hydraulic motor 2-2 and the sleeve fixing device 2-4, facilitating the replacement of the sleeve fixing device 2-4. The sleeve fixing device 2-4 is used to connect the corresponding sleeve, such as the correction sleeve 3, the large sleeve 3-1, or the small sleeve 3-2. On the one hand, the forward rotation of the rotating power head 2 can effectively rotate the steel pipe pile to the desired reinforcement position. At the same time, the soil plugging phenomenon caused by the rotation effect can effectively protect the weak welded pile joint position. On the other hand, the reverse rotation of the rotating power head 2 can effectively pull out the steel pipe pile. This machine is simple and effective to operate, has strong applicability, and, in conjunction with the above-mentioned correction and reinforcement method, can effectively remedy and strengthen misaligned or damaged piles.

[0141] In addition, the correction traction device 4 is installed on the screwing correction and reinforcement equipment 1, and the correction traction device 4 is connected to the sling 6 via the traction rope 5. Figure 6 As shown, the correction traction device 4 pulls the lasso 6 via the traction rope 5, increasing the traction power for correction. The traction rope 5 can be made of steel wire rope, which can be connected to the lasso 6 and / or the correction traction device 4 via a buckle 5-1. The lasso 6 can also be made of steel wire rope. The correction traction device 4 can be an existing electric winch or hydraulic jack, etc. In this invention, an electrically controlled correction traction device is preferred. By utilizing the difference in the amount of electricity input to the correction traction device 4, the rotation speed of the correction traction device 4 can be different, ultimately outputting different amounts of pulling force. Different gears can be set, and different gears can be selected according to the actual site conditions to achieve the purpose of accurately correcting the deviation of the pile.

[0142] Solid square piles are commonly used as pile foundations in soft soil areas. However, due to the unique soil properties in these areas, displacement and weld breakage of these solid square piles are particularly common. Depending on the specific circumstances of solid precast square piles used in soft soil areas, different treatment methods can be adopted to address situations where displacement or weld breakage leads to insufficient bearing capacity. Figure 7The flowchart of the method for correcting and reinforcing solid precast square piles in soft soil areas according to the present invention is shown. If the solid square piles are misaligned on site, reinforcement can be carried out according to the following procedure:

[0143] A. If a precast solid core square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient after testing, but no weld breakage or pile breakage is observed, the aforementioned method for correcting the misalignment of precast solid core square piles in soft soil areas will be used. This involves using a rotary correction and reinforcement device 1 and a casing to correct the misalignment of the precast solid core square pile. The pile will then be retested. If the bearing capacity meets the requirements, the pile will pass inspection. If the bearing capacity does not meet the requirements, the aforementioned method for correcting the misalignment of precast solid core square piles in soft soil areas will be used to further enlarge and reinforce the pile. This involves using a casing for correction, followed by concrete pouring or a combination of concrete pouring and casing placement to enlarge and reinforce the pile. After reinforcement, the pile will be retested. If the bearing capacity meets the requirements, the pile will pass inspection. If the bearing capacity still does not meet the requirements, then drilling and grouting piles will be considered for supplementary pile construction.

[0144] B. If a solid precast square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient after testing, and weld cracking occurs, but no pile breakage occurs, then the above-mentioned construction method for correcting the misalignment of solid precast square piles in soft soil areas shall be adopted to correct and enlarge the diameter of the precast square piles. That is, on the basis of using casing correction, the pile body shall be enlarged and reinforced by pouring concrete or by pouring concrete and leaving casing; and the bearing capacity shall be retested. If the bearing capacity meets the requirements, the acceptance shall be passed; if the bearing capacity still does not meet the requirements after testing, then the use of bored cast-in-place piles for supplementary piles shall be considered.

[0145] C. If a precast solid square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient, or if there are signs of weld breakage or pile breakage, the pile is unusable. In this case, a bored cast-in-place pile should be used to replace the pile. The bearing capacity should be retested. If the bearing capacity meets the requirements, the pile will be accepted. If the bearing capacity still does not meet the requirements, the pile replacement should be considered.

[0146] It is worth noting that the aforementioned method of supplementing bored cast-in-place piles is a conventional and relatively uneconomical technique. The present invention's method for correcting and reinforcing solid precast square piles in soft soil areas aims to minimize the need for supplementary piles. Instead, it seeks to meet the bearing capacity requirements by correcting and reinforcing the misaligned solid square piles. Supplementary piles will only be considered when the bearing capacity requirements are still not met after correction and reinforcement, or when the pile is broken.

[0147] Based on the actual site conditions and requirements, this invention proposes three methods: correction, reinforcement, and further enhancement of load-bearing capacity. The invention will be further described below with reference to these three embodiments.

[0148] [Example 1]

[0149] This embodiment describes a method for correcting the misalignment of solid precast square piles in soft soil areas. When a solid precast square pile is misaligned, and its bearing capacity is found to be insufficient after testing, but no weld breakage or pile fracture has been observed, this correction method is considered for reinforcement. (Refer to...) Figures 1(a) to 1(i) As shown, the specific process is as follows:

[0150] (1) The actual construction pile position is offset from the original design pile position to a certain extent, and the bearing capacity is not up to the design requirements after testing. However, there are no cases of weld breakage or pile breakage (see Figure 1(a) for the offset situation).

[0151] (2) Remove part of the surface soil at the pile head of the misaligned square pile to expose the pile top. Use the rotary power head 2 on the rotary correction and reinforcement equipment 1 to rotate forward and fix the correction sleeve 3 to 1m below the pile, i.e., D1 = 1m. The distance between the inner wall of the correction sleeve 3 and the corner of the square pile is selected as 50mm, i.e., the gap T1 = 50mm (see Figure 1(b)).

[0152] (3) After the correction sleeve 3 is constructed to the predetermined position, the correction sleeve 3 at the pile head position is fixed by using the steel wire rope sling 6 reserved on the correction reinforcement equipment 1 (see Figure 1(c)).

[0153] (4) After the steel wire rope sling 6 is effectively fixed, the solid square pile is pulled by the correction traction device 4 on the screwing correction reinforcement equipment 1 until it is restored to the original design position (see Figure 1(d)).

[0154] (5) After the offset square pile is restored to its original design position, the verticality of the square pile is checked with a testing tool. Once the requirements are met, the correction is stopped (see Figure 1(e)).

[0155] (6) After the requirements are met, fill the remaining gaps with fluidized solidified soil to fix the pile body (see Figure 1(f)).

[0156] (7) After the fluidized solidified soil has self-compacted, release the wire rope sling 6, and then use the screwing power head 2 to reverse the direction and remove the correction sleeve 3 (see Figure 1(g)).

[0157] (8) The soil in the pile head area was backfilled and restored with high-quality cohesive soil (see Figure 1(h)).

[0158] (9) Use small strain, static load and other testing methods to verify the quality and bearing capacity of the engineering pile body after correction. If the design requirements are met, the pile body will be accepted. If not, the corresponding reinforcement measures will continue to be adopted (see Figure 1(i)).

[0159] [Example 2]

[0160] This embodiment describes a method for correcting and reinforcing solid precast square piles in soft soil areas. When solid precast square piles are misaligned, and tests reveal insufficient bearing capacity and weld cracking, but no pile breakage, this solid square pile reinforcement method is considered for reinforcement. (Refer to...) Figures 2(a) to 2(k) As shown, the specific process is as follows:

[0161] (1) The actual construction pile position is offset from the original design pile position to a certain extent and the bearing capacity does not meet the design requirements after testing. There is a weld breakage in the pile splicing area, but there is no pile breakage as a whole (see Figure 2(a) for the offset situation).

[0162] (2) Remove part of the surface soil at the head of the misaligned square pile to expose the top of the pile. Use the screwing power head 2 on the screwing correction and reinforcement equipment 1 to screw the correction sleeve 3 (the distance between the inner diameter of the correction sleeve 3 and the corner of the square pile is controlled according to T2 = 250mm) to fix it 2m below the pile joint, i.e. D2 = 2m (see Figure 2(b)).

[0163] (3) After the correction sleeve 3 is constructed to the predetermined position, the correction sleeve 3 at the pile head position is fixed by using the steel wire rope sling 6 reserved on the correction reinforcement equipment 1 (see Figure 2(c)).

[0164] (4) After the steel wire rope sling 6 is effectively fixed, the solid square pile is pulled by the correction traction device 4 on the screwing correction reinforcement equipment 1 until it is restored to the original design position (see Figure 2(d)).

[0165] (5) After the misaligned square pile is restored to its original design position, the verticality of the square pile is checked with a testing tool. Once the requirements are met, the correction is stopped and the screwing power head 2 and the wire rope sling 6 are disconnected (see Figure 2(e)).

[0166] (6) The steel wire rope sling 6 is used to fix the pile body after correction. At the same time, the high-pressure jet pipe 7 is used to flush out the soil inside the correction sleeve 3 to ensure that the steel cage can be lowered smoothly (see Figure 2(f)).

[0167] (7) After the soil inside the corrective sleeve 3 is flushed, the annular steel cage 8 is lowered. The reinforcement of the annular steel cage 8 is determined according to the bearing capacity requirements. At the same time, steel bars are reserved at the top of the annular steel cage 8 for later anchoring into the foundation (see Figure 2(g)).

[0168] (8) After the ring-shaped steel cage 8 is lowered, concrete is poured (see Figure 2(h)).

[0169] (9) After the concrete has initially set, the wire rope sling 6 is untied, and the screwing power head 2 on the screwing correction reinforcement device 1 is used to remove the correction sleeve 3 (see Figure 2(i)).

[0170] (10) The soil in the pile head area was restored by backfilling with high-quality cohesive soil (see Figure 2(j)).

[0171] (11) Use small strain, static load and other testing methods to verify the quality and bearing capacity of the engineering pile body after correction. After meeting the design requirements, conduct acceptance (see Figure 2(k)).

[0172] [Example 3]

[0173] This embodiment describes a method for correcting and reinforcing solid precast square piles in soft soil areas. When solid precast square piles are misaligned, and tests show insufficient bearing capacity and weld cracking, but no pile breakage, this solid square pile reinforcement method can be considered to further improve the pile foundation's bearing capacity. (Refer to...) Figures 3(a) to 3(m) As shown, the specific process is as follows:

[0174] (1) The actual construction pile position is offset to a certain extent from the original design pile position, and the bearing capacity tested does not meet the design requirements. There is a weld breakage in the pile splicing area, but there is no pile breakage as a whole (see Figure 3(a) for the offset situation).

[0175] (2) Remove part of the surface soil at the head of the misaligned square pile to expose the top of the pile. Use the screwing power head 2 on the screwing correction and reinforcement equipment 1 to screw the large sleeve 3-1 (the distance between the inner diameter of the large sleeve 3-1 and the corner of the square pile is controlled according to T3 = 450mm) to fix it 2m below the pile joint, i.e. D3 = 2m (see Figure 3(b)).

[0176] (3) After the large casing 3-1 is constructed to the predetermined position, the steel wire rope sling 6 reserved on the screw-tightening and straightening reinforcement equipment 1 is used to fix the position of the large casing 3-1 at the pile head (see Figure 3(c)).

[0177] (4) After the steel wire rope sling 6 is effectively fixed, the solid square pile is pulled by the correction traction device 4 on the screwing correction reinforcement equipment 1 until it is restored to the original design position (see Figure 3(d)).

[0178] (5) After the misaligned square pile is restored to its original design position, the verticality of the square pile is checked with a testing tool. Once the requirements are met, the correction is stopped and the screwing power head 2 and the wire rope sling 6 are disconnected (see Figure 3(e)).

[0179] (6) The steel wire rope sling 6 is used to fix the pile body after correction. At the same time, the high pressure jet pipe 7 is used to flush out the soil inside the large casing 3-1 to ensure that the small casing 3-2 can be lowered smoothly (see Figure 3(f)).

[0180] (7) Use the screwing power head 2 on the screwing correction and reinforcement equipment 1 to screw the small sleeve 3-2 (the distance between the inner diameter of the small sleeve 3-2 and the corner of the square pile is controlled by T4 = 250mm, and the annular gap between the large and small sleeves is Δd≈200mm) to fix it 2m below the pile (see Figure 3(g)).

[0181] (8) After the small sleeve 3-2 is installed to the predetermined position and fixed, disconnect the screwing power head 2 and lower the ring steel cage 8. The reinforcement of the steel cage is determined according to the bearing capacity requirements. At the same time, steel bars are reserved at the top of the steel cage for later anchoring into the foundation (see Figure 3(h)).

[0182] (9) After the ring-shaped steel cage 8 is lowered, concrete is poured (see Figure 3(i)).

[0183] (10) After the concrete reaches its strength, backfill the large sleeve 3-1 and small sleeve 3-2 with fluidized solidified soil (see Figure 3(j)).

[0184] (11) After the fluid solidified soil is self-compacted, the wire rope sling 6 is untied, and the large sleeve 3-1 is removed by the screwing power head 2 on the screwing correction and reinforcement equipment 1, while the small sleeve 3-2 is left unremoved (see Figure 3(k)).

[0185] (12) The soil in the pile head area was backfilled and restored with high-quality cohesive soil (see Figure 3(l)).

[0186] (13) Use small strain, static load and other testing methods to verify the quality and bearing capacity of the engineering pile body after correction. After meeting the design requirements, the pile body is accepted (see Figure 3(m)).

[0187] This invention relates to a method for correcting and reinforcing solid precast square piles in soft soil areas. Depending on the different damage conditions of the misaligned piles, different correction and reinforcement methods can be freely selected. The method also allows for the selection of matching casing piles based on the actual dimensions of the piles on site. In summary, this method for correcting and reinforcing solid precast square piles in soft soil areas is effective and reliable in correcting misalignment; it significantly enhances reinforcement capacity and improves bearing capacity noticeably; the bearing capacity can be further improved by leaving steel pipes; it is not limited by materials, requiring only commonly available steel pile materials (steel pipe piles, reinforcing bars) and concrete; the steel casings can be effectively recycled and reused, achieving almost 100% recycling; the improved hydraulic rotary correction and reinforcement equipment allows all construction to be completed by this machine without the need for additional machinery; the construction speed is fast and efficient; and it is low-cost, quiet, and environmentally friendly. Specific advantages are as follows:

[0188] 1) A complete set of procedural technical means and construction methods are proposed for the correction and reinforcement of misaligned solid square piles. Based on the actual site conditions, it can provide precise guidance for the correction and reinforcement of misaligned piles. It is highly instructive and practical. Moreover, through many years of experience in a large number of actual projects, this technical method has shown significant results.

[0189] 2) The construction machinery is an improved hydraulic rotary correction and reinforcement equipment. It can complete the entire correction and reinforcement work by using a rotary power head without the need for other machinery. Moreover, the machinery has fast construction efficiency, simple operation, and strong applicability, and has the value of widespread promotion.

[0190] 3) Currently, there is no safe and effective method for correcting the deviation of solid square piles. This invention innovatively uses steel sleeves to protect the weak welded parts of the deviated piles and then uses steel wire ropes to correct the deviation, which can safely and effectively correct the deviation of solid square piles.

[0191] 4) For in-situ reinforcement of solid square piles, the only current method is to use the method of supplementary piles. This method is costly, time-consuming and polluting. This invention innovatively improves the bearing capacity of solid square piles by using a method of drilling and protecting the hole with a screw-in steel sleeve, effectively lowering the steel cage, and then pouring concrete to expand the diameter.

[0192] 5) For situations where it is necessary to further enhance the bearing capacity of in-situ solid square piles, the present invention can meet the needs of further enhancing the bearing capacity by using a method of screwing down double sleeves for hole protection, effectively lowering the reinforcing cage, leaving an inner steel sleeve, and later pouring concrete to expand the diameter.

[0193] 6) The materials required for construction are all readily available on the market, such as steel sleeves, reinforcing bars, and concrete. There are no special requirements, they are easy to purchase, and they are highly applicable.

[0194] 7) Steel casing materials can be recycled and reused in the later stages, which is environmentally friendly and further reduces construction costs.

[0195] 8) For cases where it is necessary to further enhance the bearing capacity of in-situ solid square piles, the trench between the large and small casings is backfilled with fluidized solidified soil. By utilizing the self-compacting properties of fluidized solidified soil, the compactness of the trench after the outer large casing is removed is effectively ensured, thus guaranteeing the requirement to strengthen the lateral resistance of the pile body.

[0196] 9) Solid square piles are commonly used as pile foundations in soft soil areas. However, due to the special soil properties in soft soil areas, the solid square piles are prone to misalignment and weld breakage. This invention can effectively correct and reinforce misaligned and welded solid square piles, which can significantly improve the bearing capacity of the pile foundation, save construction time and cost. Therefore, this invention has strong applicability and advanced features, and has the value of wide-ranging promotion.

[0197] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method for correcting the deviation of solid precast square piles in soft soil areas, characterized in that, The process includes the following steps: S1. Excavate part of the surface soil at the head of the offset square pile to expose the top of the pile. Use a screwing and straightening reinforcement device (1) to screw the straightening sleeve (3) to the joint position of the offset square pile and fix it so that the straightening sleeve (3) is sleeved on the outside of the offset square pile and a gap T1 is left between the straightening sleeve (3) and the offset square pile. The lower end of the straightening sleeve (3) is lowered to D1 below the joint position of the offset square pile. During the screwing and lowering process of the straightening sleeve (3), the joint position of the offset square pile is filled with the original soil by the soil plug effect to protect the weld at the joint. S2. A sling (6) is used to connect the correction sleeve (3) at the head of the misaligned square pile. The sling (6) is connected to the correction traction device (4) through a traction rope (5). S3. Use the correction traction device (4) to pull the correction sleeve (3) until the correction sleeve (3) brings the misaligned square pile back to the original design pile position; S4. After the offset square pile is restored to its original design position, the verticality of the square pile is checked using testing tools. Once the requirements are met, the correction is stopped. S5. Fill the remaining gaps on the outside of the correction sleeve (3) in step S3 with fluidized solidified soil to fix the pile body; S6. After the fluidized solidified soil has self-compacted, release the sleeve (6) and then use the screw-tightening reinforcement equipment (1) to remove the correction sleeve (3). S7. After correction, the pile head is backfilled with cohesive soil to restore it; S8. Inspect and verify the quality and bearing capacity of the pile body after correction.

2. The method for correcting the deviation of solid precast square piles in soft soil areas according to claim 1, characterized in that: If it is necessary to correct and reinforce the solid precast square piles, then: A. In step S1, a gap T2 is left between the correction sleeve (3) and the offset square pile. The lower end of the correction sleeve (3) extends down to D2 below the pile connection position of the offset square pile, where T2 > T1 and D2 > D1. B. Replace steps S5 and S6 with a concrete enlargement reinforcement step, the specific steps are as follows: After step S4 is completed, disconnect the connection between the screwing and straightening reinforcement equipment (1) and the straightening sleeve (3), and release the sling (6) on the straightening sleeve (3). Re-fix the straightened pile body with the sling (6), and use the high-pressure jet pipe (7) to flush out the soil on the inner wall of the straightening sleeve (3) to ensure that the ring steel cage (8) can be lowered smoothly. T2. Place the annular steel cage (8) between the correction sleeve (3) and the corrected engineering pile. T3. After the ring-shaped steel cage (8) is lowered, concrete is poured between the correction sleeve (3) and the corrected engineering pile. T4. After the concrete has initially set, untie the sling (6) and at the same time use the screw-tightening reinforcement equipment (1) to remove the correction sleeve (3).

3. The method for correcting the deviation of solid precast square piles in soft soil areas according to claim 1, characterized in that: If further correction and reinforcement of the solid precast square piles are required, then: A. Replace the correction sleeve (3) in step S1 with a large sleeve (3-1). Use a screwing correction and reinforcement device (1) to screw the large sleeve (3-1) to the joint position of the offset square pile and fix it so that the large sleeve (3-1) is sleeved on the outside of the offset square pile, and a gap T3 is left between the large sleeve (3-1) and the offset square pile. The lower end of the large sleeve (3-1) is lowered to D3 below the joint position of the offset square pile, where T3>T1 and D3>D1. During the screwing process of the large sleeve (3-1), the joint position of the offset square pile is filled with the original soil by the soil plug effect to protect the weld at the joint. In steps S2 and S3, the offset square pile is restored to its original design position using the large sleeve (3-1); B. Replace steps S5 and S6 with the casing-concrete composite diameter expansion reinforcement step. The specific steps are as follows: After step S4 is completed, disconnect the connection between the screwing and straightening reinforcement equipment (1) and the large sleeve (3-1), and release the sling (6) on the large sleeve (3-1). Re-fix the pile body of the corrected engineering pile using the sling (6). At the same time, use the high-pressure jet pipe (7) to flush out the soil on the inner wall of the large sleeve (3-1) to ensure that the small sleeve (3-2) can be lowered smoothly. T2. Using a screw-tightening reinforcement device (1), the small sleeve (3-2) is screwed to the pile connection position of the corrected engineering pile and fixed, so that the small sleeve (3-2) is fitted on the outside of the corrected engineering pile, and a gap T4 is left between the small sleeve (3-2) and the corrected engineering pile. T3. After the small sleeve (3-2) is fixed in the predetermined position, disconnect the connection between the screwing correction and reinforcement equipment (1) and the small sleeve (3-2), and lower the ring steel cage (8) between the small sleeve (3-2) and the corrected engineering pile. T4. After the ring-shaped steel cage (8) is lowered, concrete is poured between the small sleeve (3-2) and the corrected engineering pile. T5. After the concrete reaches its strength, backfill the trench with fluidized solidified soil between the large sleeve (3-1) and the small sleeve (3-2); T6. After the fluidized solidified soil has self-compacted, release the sleeve (6), and then use the rotary correction and reinforcement equipment (1) to remove the large sleeve (3-1), while leaving the small sleeve (3-2) intact.

4. The method for correcting the deviation of solid precast square piles in soft soil areas according to claim 1 or 2, characterized in that: The correction sleeve (3) is a circular steel pipe.

5. The method for correcting the deviation of solid precast square piles in soft soil areas according to claim 3, characterized in that: Both the large sleeve (3-1) and the small sleeve (3-2) are circular steel pipes.

6. The method for correcting the deviation of solid precast square piles in soft soil areas according to claim 2 or 3, characterized in that: The top of the ring-shaped steel cage (8) is reserved with steel bars for later anchoring into the foundation.

7. The method for correcting the deviation of solid precast square piles in soft soil areas according to claim 1, 2, or 3, characterized in that: The rotary straightening and reinforcement device (1) has a rotary power head (2) that moves up and down and adjusts the angle under the control of the rotary straightening and reinforcement device (1). The rotary power head (2) includes a rotary fixing device (2-1), a hydraulic motor (2-2), a flange connector (2-3), and a sleeve fixing device (2-4) arranged sequentially from top to bottom. The sleeve fixing device (2-4) is driven by the hydraulic motor (2-2) to rotate forward or in reverse.

8. The method for correcting the deviation of solid precast square piles in soft soil areas according to claim 1, 2, or 3, characterized in that: The correction traction device (4) is installed on the screwing correction and reinforcement equipment (1), and the correction traction device (4) is connected to the sling (6) through the traction rope (5).

9. A method for correcting and reinforcing solid precast square piles in soft soil areas, characterized in that, The on-site handling procedure is as follows: A. If a solid precast square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient after testing, but no weld breakage or pile breakage is observed, then the precast square pile should be corrected using the solid precast square pile correction construction method for soft soil areas described in claim 1; and the bearing capacity should be retested. If the bearing capacity meets the requirements, the acceptance is passed; if the bearing capacity does not meet the requirements after testing, then the precast square pile should be further reinforced by enlarging its diameter using the solid precast square pile correction construction method for soft soil areas described in claim 2 or 3; after reinforcement, the bearing capacity should be retested. If the bearing capacity meets the requirements, the acceptance is passed; if the bearing capacity still does not meet the requirements after testing, then bored cast-in-place piles should be used for supplementary piles. B. If a solid precast square pile is found to be misaligned on site, and the bearing capacity is found to be insufficient after testing, and weld cracking occurs, but no pile breakage occurs, then the solid precast square pile correction construction method for soft soil areas described in claim 2 or 3 shall be used to correct the misalignment and enlarge the diameter of the precast square pile; and the bearing capacity shall be retested. If the bearing capacity meets the requirements, the acceptance shall be passed; if the bearing capacity still does not meet the requirements after testing, bored cast-in-place piles shall be used to supplement the piles. C. If the precast solid square piles are found to be misaligned on site, and the bearing capacity is found to be insufficient after testing, and there are cases of weld cracking or broken piles, then bored cast-in-place piles should be used directly to supplement the piles. The bearing capacity will be retested. If it meets the requirements, the test will be passed. If the bearing capacity does not meet the requirements, the piles will be added.

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