A pile foundation secondary grouting offset compensation construction method

Abstract

This invention discloses a secondary grouting method for pile foundation offset compensation. First, materials are prepared, including binding a reinforcing cage and preparing geotextile bags with grouting pipes. Then, the foundation pit is constructed using the open-cut method, with sheet pile support installed. Using the sheet pile support as a template, the reinforcing cage is lowered, and optical fibers are pre-embedded within the cage before pouring concrete. After the pile foundation has initially set, the sheet pile support is removed, and multiple geotextile bags are installed around the pile foundation. After installation, backfilling with soil is performed. The pre-embedded optical fibers are connected to a fiber optic strain gauge to form a pile foundation offset monitoring device. The device monitors the pile foundation tilt offset. When the optical fiber tilt offset reaches a set threshold, grout is injected into the corresponding geotextile bags through the grouting pipes. The grouting pressure compresses the pile foundation for compensation and correction. This invention is simple to construct, has a short cycle time, low cost, real-time monitoring, and is controllable. High-precision correction can be performed without relying on the experience of construction personnel.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering, and relates to the field of pile foundation tilt control technology, specifically to a pile foundation offset compensation construction method using secondary grouting. Background Technology

[0002] Due to the structural stress characteristics, the properties of concrete materials, and local rock and soil conditions, pile foundations are prone to displacement during use. Similarly, bridge foundations and building foundations may also experience displacement during the excavation and soil stockpiling process, requiring correction. Failure to address this promptly poses a significant safety hazard to the project.

[0003] Currently, the main methods for controlling pile foundation offset are: for bridge foundations, steel-concrete composite pipes with tie rods are used. During construction, tie rods are applied to balance the lateral thrust on the arch abutment, thereby preventing offset. However, this method has drawbacks. It relies too heavily on manual control. For example, if the arch abutment tilts beyond the limit after pouring concrete into a particular steel pipe, the tie rod force is adjusted. However, this is clearly a reactive adjustment, as the arch abutment may have already exceeded the limit during concrete pouring, causing irreversible damage. Furthermore, because the arch abutment is difficult to accurately simulate, it is often difficult to accurately determine the specific adjustment value of the tie rod force, leading to the risk of over- or under-adjustment. For building foundations, the method involves excavating the foundation, using hydraulic jacks for control, and then pouring the support system. This method is complex and has too many uncontrollable factors, making it unsuitable for foundations limited by terrain conditions. With the large-scale use of buildings, foundation offset problems are becoming increasingly prominent. How to scientifically and effectively reduce the incidence of foundation offset and improve the safety performance of buildings is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned issues by providing a secondary grouting method for pile foundation offset compensation. This method eliminates excessive reliance on manual experience for adjustment, utilizing distributed fiber optic sensing technology to monitor pile foundation tilt and offset, and calculating appropriate grouting pressure and volume for secondary grouting to correct the pile foundation offset. This method features simple construction procedures, reliable quality, short construction period, and controllable construction.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention employs a secondary grouting method for pile foundation offset compensation, comprising the following steps:

[0007] Material preparation, binding of steel reinforcement cages and preparation of geotextile bags with grouting pipes;

[0008] For the foundation pit construction, the open excavation method was adopted, and steel sheet pile support was installed.

[0009] Using sheet pile support as a template, a steel cage is lowered, and optical fibers are pre-embedded in the steel cage before pouring construction.

[0010] After the initial setting of the pile foundation, the sheet pile support is removed, and multiple geotextile bags are installed around the pile foundation. After installation, the soil is filled and backfilled.

[0011] Connect the pre-embedded optical fiber to the optical fiber strain monitor to form a pile foundation offset monitoring device;

[0012] The pile foundation tilt is monitored by a pile foundation offset monitoring device. When the tilt of the fiber reaches the set threshold, grouting is performed on the corresponding grid geotextile bag through the grouting pipe. The grouting pressure is used to squeeze the pile foundation for compensation and correction.

[0013] This invention creatively corrects misaligned piles by burying geotextile bags around the pile foundation and using secondary grouting. By adjusting the grouting pressure and volume, the pile foundation can be standardized, does not rely on manual experience, has a simple construction method, low correction cost, and does not affect the progress of the main construction.

[0014] Furthermore, the geotextile bag is made of double-layer geotextile sewn together, and a grid-like casting unit is formed by sewing intermittently on the geotextile. Small holes for grout flow are reserved between adjacent grid cells. The grid pattern prevents the geotextile strip from over-expanding in some areas, which would result in a small contact area with the pile foundation during grouting and insufficient correction force. The grid unit restricts the grout inside the geotextile bag to make full contact with the pile foundation surface during grouting, providing maximum correction force under the same grouting pressure.

[0015] Furthermore, the geotextile bags are arranged in layers along the height of the pile foundation, with at least two geotextile bags in each layer surrounding the pile foundation. Layering along the height direction is beneficial for straightening the pile foundation if it is tilted, and multiple geotextile bags in each layer can be used to correct different orientations.

[0016] Furthermore, the geotextile bag is configured with at least three layers: upper, middle, and lower. By setting grouting points in the upper, middle, and lower positions (at least two grouting points at each height), correction can be performed simultaneously from top to bottom, thereby improving correction efficiency.

[0017] Furthermore, when monitoring the tilt and displacement of the pile foundation, the displacement should be calculated every 1-2 months. Alternatively, it can be monitored daily as needed. Once the displacement meets the requirements after 6 consecutive months of monitoring, the pile foundation will essentially stop shifting.

[0018] Furthermore, the grouting method for the corresponding geotextile bags via grouting pipes is as follows:

[0019] Calculate the grouting pressure and estimate the grouting volume based on the pile-soil parameters and the pile inclination angle.

[0020] Prepare the grout and grouting equipment based on the calculated grouting pressure and estimated grouting volume;

[0021] Grouting is carried out on the geotextile bags of the modified pile foundation that require grouting using a grouting device, and the grouting pressure is calculated.

[0022] When the grouting volume reaches 70-85% of the estimated volume, the pile foundation tilting and offset angle and the pile foundation correction range are checked again by the pile foundation offset monitoring device. If they are normal, grouting continues until the estimated grouting volume is reached and the monitoring frequency is increased until the pile foundation compensation correction is completed.

[0023] If the pile foundation correction range is abnormal, check the grouting device, then continue grouting to the estimated grouting volume and increase the monitoring frequency until the pile foundation compensation correction is completed.

[0024] Furthermore, the slurry is prepared by excavating a mud pit on-site.

[0025] Furthermore, the formula for calculating grouting pressure is as follows:

[0026] q=ΔΓKZ

[0027] q represents the grouting pressure, Z represents the grouting point depth, K represents the pressure coefficient (ranging from 0.03 to 0.028), and ΔΓ represents the grouting pressure adjustment coefficient. The grouting pressure adjustment coefficient is determined based on the water-cement ratio of the grout. A higher water-cement ratio results in better fluidity and higher purity of the grout, allowing for a lower adjustment coefficient. Conversely, poorer fluidity and lower purity necessitate a higher adjustment coefficient, typically ranging from 0.9 to 1.4. Based on the modified pile foundation design of this invention, the optimal range for the grouting pressure adjustment coefficient is 0.8 to 1.2. This invention introduces a pressure coefficient and a pressure adjustment coefficient, making the calculated grouting pressure more accurate and allowing for the selection of the minimum pressure that meets the correction conditions, thereby reducing equipment requirements.

[0028] Furthermore, the geotextile bags are arranged in three equidistant layers (upper, middle, and lower), and three grouting points are set at the top, middle, and bottom of the pile foundation. The grouting pressure calculation formula for each grouting point is as follows:

[0029]

[0030]

[0031] q3=ΔΓKZ3=HsinθΔΓK

[0032] Where q1, q2, and q3 represent the grouting pressures at the upper, middle, and lower grouting points, respectively; Z1, Z2, and Z3 represent the depths at the upper, middle, and lower grouting points, respectively; H represents the pile height; and θ represents the pile inclination angle.

[0033] Furthermore, the formula for estimating the grouting volume at each grouting point is as follows:

[0034]

[0035]

[0036]

[0037] In the above formula, Q1, Q2, and Q3 represent the estimated grouting volume at the upper, middle, and lower grouting points, respectively.

[0038] A is the grouting coefficient, with a value ranging from 0.7 to 0.9;

[0039] β is the grouting loss coefficient, with a value ranging from 1.1 to 1.4;

[0040] R is the grouting diffusion radius;

[0041] N1, N2, and N3 represent the soil porosity at the upper, middle, and lower grouting points, respectively, while N2′ and N3′ represent the equivalent soil porosity at the middle and lower grouting points, respectively.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] 1. This invention does not rely on human experience. It uses a pile foundation offset monitoring device to accurately monitor the pile foundation offset. After detecting the tilt offset, it uses empirical formulas to calculate the grouting pressure and the estimated grouting volume. Finally, it combines the feedback of the grouting effect to verify and correct the pile foundation, making the pile foundation correction standardized. Even inexperienced construction personnel can carry out the work according to the construction manual compiled by this invention, without relying on the personal experience of the construction personnel.

[0044] 2. The present invention utilizes geotextile bag cell unitization in the existing grouting correction process to prevent local grout accumulation that could lead to correction failure. The present invention uses geotextile bag cell unitization to evenly disperse the grout on the pile foundation surface, thereby obtaining the maximum correction force under the same grouting pressure.

[0045] 3. This invention features simple construction, short construction period, low cost, real-time monitoring, and controllability. For bridges with high traffic volume, this method minimizes disruption to normal traffic operations while simultaneously monitoring changes in pile foundation offset in real time. Based on the monitoring data, the grouting volume is precisely controlled, thereby solving the pile foundation offset problem. Attached Figure Description

[0046] Figure 1 This is a flowchart of the pile foundation offset compensation construction method for secondary grouting according to the present invention.

[0047] Figure 2 This is a schematic diagram illustrating the process of monitoring the tilt offset of a pile foundation using a pile foundation offset monitoring device in an embodiment of the present invention.

[0048] Figure 3 This is a schematic diagram of a single geotextile bag after it has been unfolded.

[0049] Figure 4 This is a frontal view of a geotextile bag installed on a pile foundation.

[0050] Figure 5 This is a schematic diagram of the rear side of a geotextile bag installed on a pile foundation.

[0051] Figure 6 This is a schematic diagram of the cross-section of a geotextile bag installed on a pile foundation.

[0052] Figure 7 A schematic diagram of the connectors for installing geotextile bags.

[0053] Figure 8 This is a schematic diagram of the modified pile foundation principle of the present invention.

[0054] Figure 9 This is an equivalent diagram of a single format unit after expansion.

[0055] 100-Grid geotextile bag, 110-Grouting port, 120-Connector, 121-First connector, 122-Second connector, 123-Connecting groove, 124-Connector head; 200-Pile foundation, 300-Grouting pipe, 400-Grouting point. Detailed Implementation

[0056] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0057] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0058] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0059] like Figure 1 and Figure 2 As shown, the present invention provides a construction method for secondary grouting of pile foundation 200 offset compensation, including the following steps:

[0060] S1. Material preparation, binding of steel reinforcement cage and preparation of 100 grid geotextile bags with 300 grouting pipes;

[0061] In this embodiment, the reinforcement cage binding can be carried out according to existing construction specifications; the grid-type geotextile bag 100 is made of double-layer geotextile sewn together, and a grid-like casting unit is formed by sewing intermittently on the geotextile. Small holes for grout flow are reserved between adjacent cells. A grouting port 110 is reserved in the middle of each grid-type geotextile bag 100. The unfolded grid-type geotextile bag 100 is as follows: Figure 3 As shown, by dividing the geotextile strip into a unit format, the grout can be evenly dispersed during grouting, rather than concentrated in a localized area, which would prevent the grouting correction from being completed smoothly.

[0062] S2. For foundation pit construction, the site is first leveled, and then the foundation pit is constructed using the open excavation method according to the design drawings, with steel sheet pile support installed.

[0063] S3. Using sheet pile support as a template, the steel cage is lowered, and fiber optic cables are pre-embedded in the steel cage before pouring. The fiber optic cables are used to monitor whether the pile foundation tilts in the later stages.

[0064] S4. After the initial setting of pile foundation 200, the steel sheet pile support is removed, and multiple grid geotextile bags are installed around pile foundation 200. After installation, soil is filled and backfilled.

[0065] In this embodiment, the geotextile bag is arranged in three layers: upper, middle, and lower, as follows: Figures 4 to 6As shown, each layer is equipped with two grid-type geotextile bags, and the two grid-type geotextile bags in each layer are directly connected by connectors to form a ring that surrounds and wraps around the pile foundation 200. The connectors can be binding ropes or special connectors, such as those shown in the figure, including two first connectors 121 and one second connector 122. The two first connectors 121 are sewn onto the sides of the two grid-type geotextile bags to be spliced. The two first connectors 121 are respectively provided with connecting grooves 123 on opposite sides. The two ends of the second connector 122 are detachably fixed in the connecting grooves 123 on both sides by a snap-fit ​​structure.

[0066] For example, such as Figure 7 As shown, the first connector 121 can be made of plastic with a certain degree of elasticity. The cross-sectional area inside the connecting groove 123 is larger than that at the opening. The second connector 122 has connector heads 124 with enlarged cross-sections at both ends. The first connector 121 and the second connector 122 are connected by inserting the connector heads 124 into the connecting groove 123 with external force (after being squeezed by external force, the two sides of the connecting groove 123 will deform and open). This structure can be quickly connected and meets the requirements. It should be noted that this connection method of the present invention only needs to ensure that the geotextile bag maintains its shape before backfilling. After backfilling, the geotextile bag maintains its shape by the backfill soil. There is no need for the connection function of the connector. Therefore, the strength of this connection method of the present invention is sufficient to meet the requirements.

[0067] Each geotextile bag is provided with a grouting port 110. A grouting pipe 300 is installed on the grouting port 110 and extends to the top of the pile foundation 200 to prepare for subsequent grouting. Generally, the grouting port 110 should be located in the middle of the entire geotextile bag. For example, the grouting pipe 300 can be a sleeve valve pipe with a diameter of 30mm.

[0068] S5. Connect the pre-embedded optical fiber to the optical fiber strain monitor to form a pile foundation offset monitoring device. The optical fiber detection technology can be the existing technology. This invention does not make any improvements to this part. For example, CN113899343B, CN106643542, CN217358508U, and tilt sensors can all be used.

[0069] S6. Monitor the tilt offset of pile foundation 200 using the pile foundation 200 offset monitoring device, with a monitoring frequency of once every 1-7 days; when the fiber optic tilt offset reaches the set threshold, grout the corresponding grid geotextile bag through the grouting pipe 300, and compensate and correct the pile foundation 200 by squeezing it with grouting pressure.

[0070] The grouting method for the corresponding geotextile bags via grouting pipe 300 is as follows:

[0071] S6.1 Calculate the grouting pressure and estimated grouting volume based on the pile soil parameters and the 200° inclination angle of the pile foundation;

[0072] S6.1.1 Calculate grouting pressure

[0073] The grouting pressure is q, and the burial depth of the grouting pipe 300 is z1. Taking z1 as the location for calculation, the lateral static earth pressure borne by the pile foundation 200 wrapped by the geotextile bag 100 at this location is σ1 = k0γz1. As long as the grouting pressure q ≤ σ1, the soil will not undergo lateral deformation or displacement. When the grouting pressure q > σ1 is selected, the lateral soil deformation will occur during grouting because the grouting pressure is greater than the lateral static earth pressure. Here, k0 represents the earth pressure coefficient, and γ represents the unit weight of the soil at the burial depth of the pile foundation 200.

[0074] After introducing the grouting pressure coefficient and the grouting pressure adjustment coefficient, the formula for calculating the grouting pressure is as follows:

[0075] q=ΔΓKZ

[0076] q is the grouting pressure, Z is the grouting point depth of 400 mm, K is the pressure coefficient, which ranges from 0.03 to 0.028, and ΔΓ is the grouting pressure adjustment coefficient, which typically ranges from 0.9 to 1.4.

[0077] As shown in the figure, the height of pile foundation 200 is H, the offset angle is θ, and the horizontal offset of pile foundation 200 is x.

[0078] For the correction of the inclined pile foundation 200, the optimal method is to perform grouting correction in three layers: upper, middle, and lower. Therefore, geotextile bags are installed in three equidistant layers (upper, middle, and lower), and three grouting points 400 are set at the upper, middle, and lower parts of the pile foundation 200. Figure 8 As shown, in this inclined state, the upper grouting point 400 should be located on the right side of the pile foundation 200, the middle grouting point 400 on the right side, and the lower grouting point 400 on the left side of the pile foundation 200. During grouting, the upper and lower parts of the pile foundation 200 will respectively undergo grouting as follows: Figure 8 The correction can be completed with a slight rotation as indicated by the middle arrow (the actual tilt angle is much smaller than the angle shown in the attached diagram); the formula for calculating the grouting pressure of 400 at each grouting point is as follows:

[0079]

[0080]

[0081] q3=ΔΓKZ3=HsinθΔΓK

[0082] Where q1, q2, and q3 represent the grouting pressures at the upper, middle, and lower grouting points 400, respectively; Z1, Z2, and Z3 represent the depths at the upper, middle, and lower grouting points 400, respectively; H represents the height of the pile foundation 200; and θ represents the inclination angle of the pile foundation 200.

[0083] S6.1.2 The estimated calculation formula for the grouting volume of 400 at each grouting point is as follows:

[0084]

[0085]

[0086]

[0087] In the above formula, Q1, Q2, and Q3 represent the estimated grouting volume at the upper, middle, and lower grouting points of 400, respectively;

[0088] A is the grouting coefficient, with a value ranging from 0.7 to 0.9;

[0089] β is the grouting loss coefficient, with a value ranging from 1.1 to 1.4;

[0090] R is the grouting diffusion radius, which is mainly related to the expanded volume of each grid unit of the geotextile bag. In this embodiment, half of the minimum value of the length, width, and height of each grid unit is taken as the grouting diffusion radius, and the calculation formula is as follows:

[0091]

[0092] ξ, ζ, and η represent the length, width, and height of the expanded grid unit, respectively.

[0093] N1, N2, and N3 represent the soil porosity at 400 mm from the upper, middle, and lower grouting points, respectively, obtained through geological exploration; N2′ and N3′ are the equivalent soil porosity at 400 mm from the middle and lower grouting points, respectively.

[0094] S6.2 Prepare grout and grouting equipment according to the calculated grouting pressure and estimated grouting volume;

[0095] The grout is prepared by excavating a mud pit on site and mixing the grout on site; the grouting device can use a dual-liquid grouting pump such as HFV5D or KBY50 / 70, and is equipped with a 300-line high-pressure grouting pipe system and grouting equipment.

[0096] S6.3. Use a grouting device to grout the geotextile bags of the modified pile foundation that require grouting, and grout according to the calculated grouting pressure.

[0097] S6.4 When the grouting volume reaches 70-85% of the estimated volume, the tilting and offset angle of the pile foundation 200 and the correction range of the pile foundation 200 are checked again by the pile foundation 200 offset monitoring device. If they are normal, continue grouting to the estimated grouting volume and increase the monitoring frequency until the pile foundation 200 compensation correction is completed.

[0098] If the correction range of pile foundation 200 is abnormal, check the grouting device, then continue grouting to the estimated grouting volume and increase the monitoring frequency until the pile foundation 200 compensation correction is completed.

[0099] The way to determine whether the correction range is normal is to see if the difference between the correction range after grouting and the calculated value is within the allowable range, such as an error of less than 20%.

[0100] It should be noted that in step S6.4, when the grouting volume reaches 70% and 85% of the estimated amount, it can be judged whether the error with the calculated value is within the allowable range, so as to check the grouting device in time and prevent the correction failure caused by insufficient grouting pressure due to grouting device failure.

[0101] It should be noted that if the pile foundation 200 offset monitoring device monitors the tilt offset of pile foundation 200 within the required range for 6 consecutive months, then grouting repair is not required.

[0102] After grouting repair, continuous monitoring is required for 3 months. If the pile foundation shifts again, it will be corrected by grouting the remaining geotextile bags.

[0103] The above embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Although the invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the invention do not depart from the spirit and scope of the invention and should be covered within the scope of the claims of the invention.

Claims

1. A method for pile foundation offset compensation using secondary grouting, characterized in that, Includes the following steps: Material preparation, binding of steel reinforcement cages and preparation of geotextile bags with grouting pipes; For the foundation pit construction, the open excavation method was adopted, and steel sheet pile support was installed. Using sheet pile support as a template, a steel cage is lowered, and optical fibers are pre-embedded in the steel cage before pouring construction. After the initial setting of the pile foundation, the sheet pile support is removed, and multiple geotextile bags are installed around the pile foundation. After installation, the soil is filled and backfilled. Connect the pre-embedded optical fiber to the optical fiber strain monitor to form a pile foundation offset monitoring device; The pile foundation tilt offset is monitored by a pile foundation offset monitoring device. When the fiber optic tilt offset reaches the set threshold, grouting is performed on the corresponding grid geotextile bag through the grouting pipe. The pile foundation is then squeezed by the grouting pressure to compensate and correct the offset. The grouting method for the corresponding geotextile bags via grouting pipes is as follows: Based on the pile-soil parameters and the pile inclination angle, the grouting pressure and estimated grouting volume are calculated. The formula for calculating the grouting pressure is as follows: q is the grouting pressure. Z The depth of the grouting point. K This is the pressure coefficient, with a value ranging from 0.03 to 0.

028. This is the grouting pressure adjustment coefficient, with a value ranging from 0.9 to 1.4; Prepare the grout and grouting equipment based on the calculated grouting pressure and estimated grouting volume; Grouting is carried out on the geotextile bags of the modified pile foundation that require grouting using a grouting device, and the grouting pressure is calculated. When the grouting volume reaches 70-85% of the estimated volume, the pile foundation tilting and offset angle and the pile foundation correction range are checked again by the pile foundation offset monitoring device. If they are normal, grouting continues until the estimated grouting volume is reached and the monitoring frequency is increased until the pile foundation compensation and correction are completed. If the pile foundation correction range is abnormal, check the grouting device, then continue grouting to the estimated grouting volume and increase the monitoring frequency until the pile foundation compensation correction is completed.

2. The pile foundation offset compensation construction method with secondary grouting according to claim 1, characterized in that, The geotextile bag is made of double-layer geotextile sewn together, and a grid-like casting unit is formed by sewing the geotextile at intervals. Small holes for grout flow are reserved between adjacent cells.

3. The pile foundation offset compensation construction method with secondary grouting according to claim 1, characterized in that, The geotextile bags are arranged in layers along the height of the pile foundation, with at least two geotextile bags in each layer surrounding the pile foundation.

4. The pile foundation offset compensation construction method with secondary grouting according to claim 3, characterized in that, The geotextile bags are configured with at least three layers: upper, middle, and lower.

5. The pile foundation offset compensation construction method with secondary grouting according to claim 1, characterized in that, When monitoring the tilt and offset of pile foundations, the offset should be calculated every 1-2 months.

6. The pile foundation offset compensation construction method with secondary grouting according to claim 1, characterized in that, The slurry was prepared by excavating a mud pit on site.

7. The pile foundation offset compensation construction method with secondary grouting according to claim 1, characterized in that, The geotextile bags are arranged in three layers (top, middle, and bottom) at equal intervals. Three grouting points are set at the top, middle, and bottom of the pile foundation. The grouting pressure calculation formula for each grouting point is as follows: in, , , These represent the grouting pressures at the upper, middle, and lower grouting points, respectively. , , These represent the depths of the upper, middle, and lower grouting points, respectively, with H representing the pile height. This indicates the tilt angle of the pile foundation.

8. The pile foundation offset compensation construction method with secondary grouting according to claim 7, characterized in that, The formula for estimating the grouting volume at each grouting point is as follows: In the above formula, , , These represent the estimated grouting volumes for the upper, middle, and lower grouting points, respectively. A is the grouting coefficient, with a value ranging from 0.7 to 0.9; This is the grouting loss coefficient, with a value ranging from 1.1 to 1.

4. R The grouting diffusion radius; , , These represent the soil porosity at the upper, middle, and lower grouting points, respectively. , These are the equivalent soil porosity at the grouting points in the middle and lower layers, respectively.

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