Construction method of photovoltaic cast-in-place pile

Abstract

The invention discloses a construction method of a photovoltaic cast-in-place pile, and relates to the technical field of photovoltaic power station pile foundation construction. The construction method of the photovoltaic cast-in-place pile comprises the steps that lofting is conducted according to the designed pile foundation point position, and the arrangement area of a photovoltaic pile foundation is determined; sampling points are determined in the arrangement area of the photovoltaic pile foundation according to the terrain in the first direction, three-dimensional coordinates of all the sampling points are collected, and longitudinal section lines of all strings of the photovoltaic pile foundation square matrix are generated; obtaining the pile top elevation of each string, and superposing the pile top elevation with the longitudinal section line of each string of the photovoltaic pile foundation square matrix to obtain the field level elevation of each pile foundation; performing field leveling according to the field leveling elevation; constructing to generate a cast-in-place pile; wherein each group of strings are arranged along a first direction. The construction method of the photovoltaic cast-in-place pile is beneficial for reducing the engineering cost.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power station pile foundation construction, and in particular to a photovoltaic cast-in-place pile construction method. Background Art

[0002] With the rapid development of the global economy, energy demand continues to grow. Traditional fossil energy such as coal, oil and natural gas are facing increasingly severe problems such as resource shortage and environmental pollution. In this context, solar energy, as a clean and renewable energy source, has received widespread attention. The photovoltaic industry has risen rapidly, and photovoltaic cast-in-place concrete pouring technology is one of the key technologies supporting the construction of photovoltaic power stations.

[0003] In the current construction process of photovoltaic bored piles, there is a serious problem of excessive concrete volume. According to calculations, in some plots, the filling coefficient of concrete bored piles reaches about 1.6, which seriously exceeds the design requirements and increases the cost of project construction. Summary of the invention

[0004] The present invention provides a construction method for photovoltaic cast-in-place piles, which can be beneficial to reducing engineering costs.

[0005] The construction methods of photovoltaic cast-in-place piles include: According to the designed pile foundation points, carry out layout and determine the layout area of ​​the photovoltaic pile foundation; Determine sampling points in the photovoltaic pile foundation arrangement area according to the terrain in the first direction, collect the three-dimensional coordinates of each sampling point, and generate the longitudinal section line of each group of strings of the photovoltaic pile foundation array; Obtain the pile top elevation of each string group, and superimpose the pile top elevation with the longitudinal section line of each string group of the photovoltaic pile foundation array to obtain the field level elevation of each pile foundation; Carry out site leveling according to site leveling elevation; The construction generates cast-in-place piles; Wherein, each group of strings is arranged along a first direction.

[0006] In an exemplary embodiment of the present disclosure, a sampling point is determined according to the terrain in a first direction in an arrangement area of ​​a photovoltaic pile foundation, and a longitudinal section line of each group of strings of a photovoltaic pile foundation array is generated, including: In the area where the front column pile foundation points of each group of strings are arranged, sampling points are determined according to the terrain in the first direction, and a longitudinal section line of the front column is generated; In the area where the pile foundation points of the rear columns of each group of strings are arranged, sampling points are determined according to the terrain in the first direction, and a longitudinal section line of the rear columns is generated; Superimpose the pile top elevation with the longitudinal section lines of each group of strings in the photovoltaic pile foundation array to obtain the field level elevation of each pile foundation, including: Superimpose the pile top elevation with the longitudinal section lines of the front column and the rear column to obtain the field elevation of each pile foundation. The difference between the pile top height of the front column and the pile top height of the rear column in the same string shall not exceed 10mm.

[0007] In an exemplary embodiment of the present disclosure, determining a sampling point according to the terrain in a first direction includes: Setting sampling points at the undulating positions along the first direction; In a region with a uniform slope along the first direction, sampling points are set at equal intervals.

[0008] In an exemplary embodiment of the present disclosure, site leveling is performed according to the site leveling elevation, including: superimposing the pile top elevation with the longitudinal section lines of each group of strings of the photovoltaic pile foundation array, calculating the site leveling height difference of each pile foundation; and excavating and replacing the local pile position according to the site leveling height difference of each pile foundation.

[0009] In an exemplary embodiment of the present disclosure, obtaining the pile top elevation of each string group includes: controlling the pile top elevations in the same string group to be in the same plane.

[0010] In an exemplary embodiment of the present disclosure, obtaining the pile top elevation of each string group includes: controlling the pile top height difference of adjacent brackets between adjacent strings to be less than 200 mm.

[0011] In an exemplary embodiment of the present disclosure, constructing and generating cast-in-place piles includes: Drilling and cleaning holes: Drill and clean holes according to the designed pile foundation point positioning and marking; Steel cage installation; Install the casing; Concrete pouring; Install embedded parts, which are U-shaped bolts; Curing of concrete.

[0012] In an exemplary embodiment of the present disclosure, the drilling and hole cleaning process includes: performing rotary drilling according to the site level elevation of each pile foundation to make the exposed height of the front column pile body and the rear column pile body of the same group of strings equal; after drilling with a rotary drilling machine, manually cleaning the hole.

[0013] In an exemplary embodiment of the present disclosure, during the concrete pouring process, the pile foundation is formed by pouring at one time.

[0014] In an exemplary embodiment of the present disclosure, the distance between the installation position of the steel cage and the sleeve is 3.2 cm to 3.5 cm.

[0015] The construction method of photovoltaic cast-in-place piles disclosed in the present invention utilizes the original landform data collected in the field to generate the longitudinal section line of the terrain, which can provide a data basis for the subsequent site leveling operation. By superimposing the longitudinal section lines of each group of strings that characterize the original landform with the designed site leveling elevation line, and then performing site leveling, it has scientific reliability and can improve the accuracy of site leveling, which can ensure that the elevation of the pile top after pile formation meets the design requirements, and can ensure that the pile body length meets the design requirements and is not too long or too short. The construction method of photovoltaic cast-in-place piles disclosed in the present invention can ensure that the photovoltaic cast-in-place piles meet the bearing requirements while enabling the construction of the photovoltaic cast-in-place piles to conform to the original landform characteristics of the site and follow the slope, thereby reducing the amount of concrete waste and reducing construction costs.

[0016] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0018] Figure 1 The present invention is a flowchart of an exemplary embodiment of the construction method of the photovoltaic cast-in-place pile disclosed in the present invention.

[0019] Figure 2 This is an overlay diagram of the pile top elevation and the longitudinal section lines of each group of strings in the photovoltaic pile foundation array in an exemplary embodiment of the construction method of the photovoltaic cast-in-place pile disclosed in the present invention.

[0020] Figure 3 A flowchart of generating a cast-in-place pile for construction in an exemplary embodiment of a construction method of a photovoltaic cast-in-place pile disclosed herein. DETAILED DESCRIPTION

[0021] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0022] Unless otherwise specified or explained, the technical terms or scientific terms used in the present disclosure shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The terms "one", "an", "the", "said" and "at least one" are used to indicate the existence of one or more elements / components / etc.; the terms "include" and "have" are used to indicate an open-ended inclusion and mean that in addition to the listed elements / components / etc., there may be other elements / components / etc. The terms "connect", "fixed", etc. should be understood in a broad sense. For example, unless otherwise specified, "connection" may be a fixed connection, a movable connection, an integral connection, or a detachable connection, and may be directly connected or indirectly connected through an intermediate medium. The present disclosure is explained by taking the arrangement of each group of strings along the east-west direction and the first direction as the east-west direction as an example. It can be understood by those skilled in the art that for the scenario where the photovoltaic bracket is arranged along other directions, the first direction may also refer to other directions, and the construction method provided in the present disclosure is not limited to a specific direction.

[0023] The present invention provides a construction method of photovoltaic cast-in-place piles, referring to Figure 1 As shown, it includes steps S100 to S500.

[0024] Step S100: Lofting is performed according to the designed pile foundation points to determine the layout area of ​​the photovoltaic pile foundation; Step S200: determining sampling points in the photovoltaic pile foundation arrangement area according to the terrain in the first direction, collecting the three-dimensional coordinates of each sampling point, and generating the longitudinal section line of each group of strings of the photovoltaic pile foundation array; Step S300: Obtain the pile top elevation of each group of strings, and superimpose the pile top elevation with the longitudinal section line of each group of strings of the photovoltaic pile foundation array to obtain the field level elevation of each pile foundation; Step S400: leveling the site according to the site leveling elevation; Step S500: construct and generate cast-in-place piles; Wherein, each group of strings is arranged along a first direction.

[0025] In step S100, for each string, one or more control points can be placed, and the parameters of the control points and the calibration of the instruments are performed through the existing control points. Only after the calibration is correct can the stakeout work of the pile foundation points be carried out, and the measuring instruments used must be qualified instruments calibrated by an authoritative calibration unit.

[0026] Computer-aided design vectorization can be carried out based on the plot sub-array plan provided by the design unit. After the position is verified to be correct by internal work, field surveying can be carried out.

[0027] In step S200, during the process of performing field work on the sub-array pile foundation point layout, the sampling points can be determined according to the terrain in the first direction, the three-dimensional coordinates of each sampling point can be collected, and the longitudinal section line of each group of strings in the photovoltaic pile foundation array can be generated. Among them, each group of strings is arranged along the first direction. For example, taking the arrangement of each group of strings in a certain plot from west to east as an example, when performing field work on the sub-array pile foundation point layout, the sampling points can be determined according to the terrain from west to east, the X, Y, H three-dimensional coordinates of the points can be collected, and the longitudinal section line from west to east for each sub-array can be generated through geographic surveying and mapping software such as CASS software.

[0028] In step S300, the pile top elevations between the strings can be designed according to the pile top elevation design requirements of each string group. After the pile top elevations are obtained, they are superimposed with the longitudinal section line from west to east obtained in step S200 to calculate the elevation of each pile foundation field.

[0029] In step S400, the site is leveled according to the calculated site leveling elevation; in step S500, cast-in-place piles are constructed, thereby realizing the construction of photovoltaic cast-in-place piles.

[0030] It can be seen that the construction method of photovoltaic cast-in-place piles disclosed in the present invention utilizes the original landform data collected in the field to generate the longitudinal section line of the terrain, which can provide a data basis for the subsequent site leveling operation. By superimposing the longitudinal section lines of each group of strings that characterize the original landform with the designed site leveling elevation line, and then performing site leveling, it has scientific reliability and can improve the accuracy of site leveling. It can ensure that the elevation of the pile top after pile formation meets the design requirements, and that the length of the pile body meets the design requirements and is not too long or too short. The construction method of photovoltaic cast-in-place piles disclosed in the present invention can ensure that the photovoltaic cast-in-place piles meet the bearing requirements while enabling the construction of the photovoltaic cast-in-place piles to conform to the original landform characteristics of the site and follow the slope, thereby reducing the amount of concrete waste and reducing construction costs.

[0031] Specifically, in step S100, in view of the large number of component support foundations, dense layout, and difficulty in positioning, when laying out the pile foundation points, four control points can be laid out for each string, with two control points for each front column and rear column. Use a steel ruler to lay out the lines, use a hanging rope to control the longitudinal and transverse axes of each component support foundation, and use a level to control the elevation of each component support foundation. When laying out the photovoltaic pile foundation points in the field, steel nails and red cloth strips can be used for marking.

[0032] In step S200, in an exemplary embodiment, the following steps may be included: In the area where the front column pile foundation points of each group of strings are arranged, sampling points are determined according to the terrain in the first direction, and a longitudinal section line of the front column is generated; In the area where the pile foundation points of the rear columns of each string are arranged, sampling points are determined according to the terrain in the first direction, and the longitudinal section lines of the rear columns are generated.

[0033] When the pile top elevation is superimposed with the longitudinal section line of each group of strings of the photovoltaic pile foundation array in step S300, the pile top elevation, the longitudinal section line of the front column, and the longitudinal section line of the rear column can be superimposed to obtain the field level elevation of each pile foundation. Exemplarily, the pile top height of the front column and the pile top height of the rear column in the same group of strings can be equal, or the difference between the pile top height of the front column and the pile top height of the rear column in the same group of strings is not greater than 10 mm. Figure 2 , L1 line shows a schematic diagram of the longitudinal section line of the front column, and L2 line shows a design height of the pile top elevation according to the slope. For easy observation, Figure 2 The longitudinal section line of the rear column is not shown. In the exemplary embodiment of the present disclosure, the longitudinal section line of the rear column can also be superimposed with the longitudinal section line L1 of the front column and the pile top elevation line L2 to obtain the field level elevation of each pile foundation.

[0034] Sampling points are determined according to the terrain. Specifically, sampling points can be set at locations with undulating terrain. For example, sampling points can be set at the lowest point of low-lying terrain, the highest point of uplifted terrain, or at locations where the slope angle changes. Figure 2 The sampling point A shown in FIG. For a region with a uniform slope, the sampling points can be set at equal intervals. For example, for a region with a gentle slope, such as a region with a slope of 2% to 10%, the interval between the sampling points can be set larger; for a region with a steep slope, the interval between the sampling points can be set smaller. Figure 2 The sampling point B shown in FIG. This exemplary embodiment can make the generated longitudinal section line more accurately reflect the landform characteristics and provide more accurate data support for subsequent field leveling operations.

[0035] In step S300, the pile top elevation of each string group is obtained. This may include controlling the pile top elevations within the same string group to be in the same plane. Specifically, the influence of the terrain slope should be considered when determining the pile top elevation and the principle of "following the slope" should be followed. For the construction of the top elevation of the photovoltaic support pile foundation, within the same string group, the fixed support pile top elevations should be in the same plane. The pile top elevations in the same plane described in the present disclosure refer to the pile top elevations being coplanar, which includes both the pile top elevations being in the same horizontal plane and the pile top elevations being in an inclined plane.

[0036] For example, for the construction of the top elevation of the photovoltaic support pile foundation, the difference in the top elevation of the adjacent supports between adjacent strings can be controlled to be less than 200 mm. For example, for two adjacent strings in the east-west direction, the difference between the top elevation of the pile at the east edge of the string located on the west side and the top elevation of the pile at the west edge of the string located on the east side is less than 200 mm.

[0037] Exemplarily, during the lofting, the position deviation of the pile foundation does not exceed 30 mm, and the height deviation of the pile top does not exceed 10 mm.

[0038] In step S400, the site is leveled according to the site leveling elevation, including: superimposing the pile top elevation with the longitudinal section line of each group of strings of the photovoltaic pile foundation array to calculate the site leveling height difference of each pile foundation; excavating and replacing the local pile position according to the site leveling height difference of each pile foundation. After designing the pile top elevation between the groups of strings, superimposing it with the longitudinal section line of each group of strings of the photovoltaic pile foundation array, such as the longitudinal section line of the front column from west to east and the longitudinal section line of the rear column from west to east, the height difference of each pile foundation site leveling can be calculated. Local site leveling according to the site leveling height difference is particularly suitable for project areas with serious irregular terrain ups and downs. Moreover, the local site leveling is calculated based on the slope elevation and the original terrain data. The data has a scientific basis, which is conducive to ensuring that in the subsequent construction work, the pile top elevation of each group of strings can be designed according to the slope according to the design requirements, ensuring that the length of the pile body is not too long, which is conducive to reducing the waste of concrete and reducing construction costs. In particular, the bearing capacity of the foundation after replacement should meet the design requirements.

[0039] Step S500, construct and generate cast-in-place piles, refer to Figure 3 As shown, it may include steps S510 to S560: Step S510: drilling and cleaning holes, marking and drilling holes according to the designed pile foundation point positioning and cleaning; Step S520: installing the steel cage; Step S530: installing the casing; Step S540: pouring concrete; Step S550: installing embedded parts, which are U-shaped bolts; Step S560: Curing of concrete.

[0040] Specifically, in step S510, the drilling and hole cleaning process includes: rotary drilling according to the site level elevation of each pile foundation, so that the exposed height of the front column pile body and the rear column pile body of the same group of strings are equal. For example, the exposed height of the front column pile body and the rear column pile body of the same group of strings are both 30cm to 50cm. The drilling commander needs to measure each pile hole to ensure that it meets the design requirements and the hole body does not exceed the standard.

[0041] When drilling, align the center of the drill bit with the center of the hole, use a plumb bob or level to control the verticality of the drill from different angles, and start drilling after the drill is corrected to be vertical. During the drilling process, strictly control its verticality and depth. If the hole is found to be inclined or offset, make corrections in time. When drilling with a drill, the drilled sand should be kept away from the edge of the hole to prevent the surrounding sand from collapsing into the hole due to vibration after the drill rod is raised, resulting in insufficient hole depth.

[0042] In an exemplary embodiment of the present disclosure, after drilling with a rotary drilling machine, the hole is manually cleaned. Specifically, if a water drill is used to drill a hole, the hole wall may increase and the amount of concrete may exceed the standard. Especially for the Gobi Desert photovoltaic power station, the site is mainly pebbles, and the use of a water drill to drill a hole may cause the hole to present an irregular shape, resulting in an excessive amount of concrete. The exemplary embodiment of the present disclosure uses a manual hole cleaning method after drilling with a rotary drilling machine, which is conducive to effectively controlling the pile foundation hole depth and hole diameter to meet the design requirements.

[0043] In an exemplary embodiment of the present disclosure, under the premise of ensuring that the pile foundation leaks 30cm to 50cm, the drilling crew needs to measure the depth of each drill hole with a tape measure based on the design line elevation required by the design and the calculated site elevation difference to ensure that the pile foundation leakage elevation is on the same horizontal plane or the same inclined plane.

[0044] In some exemplary embodiments, the drill bit size can be adjusted at any time according to the actual geological conditions on site to ensure that the hole diameter is ≥ 250 mm.

[0045] In step S520, before placing the steel cage, the steel cage may be made. The steel cage making includes checking the specifications, models and factory certificates of steel materials, conducting physical and mechanical property tests on the steel materials, and only after passing the tests can the steel cage be used for construction, and then checking the processing and making quality of the steel cage according to the design and construction specifications.

[0046] When installing the steel cage, it must be inspected and accepted by the supervisor before it can be used. Exemplarily, the steel cage can be transported to the site using a small engineering vehicle, and the steel cage can be ensured not to be damaged or deformed during the transportation process. In an exemplary embodiment of the present disclosure, the steel cage should be inspected twice when it is installed. If the steel cage is found to be deformed, it should be adjusted on site. Exemplarily, the distance between the installation position of the steel cage and the casing is 3.2cm to 3.5cm. For example, the installation position of the steel cage is 3.5cm away from the wall casing. If the installation position of the steel cage is found to be offset during the pouring process, manual adjustments should be made in a timely manner during the pouring process.

[0047] In step S530, the casing is installed after the reinforcement cage is placed properly.

[0048] In step S540, during the concrete pouring process, a construction process of vibrating while pouring can be adopted. The vibrator is inserted quickly and pulled out slowly as required, and the vibrator rod is quickly extended to the bottom of the pile foundation, and then slowly pulled out. No vibration leakage or over-vibration is allowed to occur, so as not to reduce the strength of the concrete and affect the overall quality of the concrete. In an exemplary embodiment of the present disclosure, during the concrete pouring process, the pile foundation is formed by a single pouring, eliminating secondary pouring and avoiding the formation of construction joints.

[0049] In step S550, the embedded parts are installed. The embedded parts can be processed according to the design drawings, or customized. After a single concrete pouring is completed, the U-bolt embedded parts are embedded. For example, each time the center spacing of the group string embedded parts is checked, the diagonal inspection method is added. After the embedded parts of the component bracket foundation are installed, the concrete on the top of the embedded parts should be cleared immediately.

[0050] In step S560, after the concrete pouring of the component support pile is completed, the curing starts 6 to 18 hours later. In hot seasons, it can be started 1 to 2 hours earlier depending on the degree of concrete solidification. To avoid exposure to sunlight, plastic film is used to cover the concrete surface for curing, so that the concrete surface is always kept moist. The curing time is not less than 28 days.

[0051] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A construction method for photovoltaic cast-in-place piles, characterized in that: include: According to the designed pile foundation points, carry out layout and determine the layout area of ​​the photovoltaic pile foundation; Determine sampling points in the photovoltaic pile foundation arrangement area according to the terrain in the first direction, collect the three-dimensional coordinates of each sampling point, and generate the longitudinal section line of each group string of the photovoltaic pile foundation array; Obtain the pile top elevation of each group of strings, and superimpose the pile top elevation with the longitudinal section line of each group of strings of the photovoltaic pile foundation array to obtain the field level elevation of each pile foundation; Performing site leveling according to the site leveling elevation; The construction generates cast-in-place piles; Wherein, each group of strings is arranged along the first direction.

2. The construction method of photovoltaic cast-in-place pile according to claim 1, characterized in that: Determining sampling points in the arrangement area of ​​the photovoltaic pile foundation according to the terrain in the first direction, and generating longitudinal section lines of each group of strings of the photovoltaic pile foundation array, including: In the area where the front column pile foundation points of each group of strings are arranged, sampling points are determined according to the terrain in the first direction, and a longitudinal section line of the front column is generated; In the area where the pile foundation points of the rear columns of each string are arranged, sampling points are determined according to the terrain in the first direction, and a longitudinal section line of the rear columns is generated; The pile top elevation is superimposed with the longitudinal section lines of each string of the photovoltaic pile foundation array to obtain the field level elevation of each pile foundation, including: The pile top elevation is superimposed with the longitudinal section lines of the front column and the rear column to obtain the field elevation of each pile foundation. The difference between the pile top height of the front column and the pile top height of the rear column in the same string is not greater than 10 mm.

3. The construction method of photovoltaic cast-in-place pile according to claim 2, characterized in that: Determining sampling points according to the terrain in the first direction includes: Setting the sampling points at the undulating positions along the first direction; The sampling points are arranged at equal intervals in a region with a uniform slope along the first direction.

4. The construction method of photovoltaic cast-in-place pile according to claim 1, characterized in that: The site is leveled according to the site leveling elevation, including: superimposing the pile top elevation with the longitudinal section lines of each group of strings of the photovoltaic pile foundation array to calculate the site leveling height difference of each pile foundation; and excavating and replacing the local pile position according to the site leveling height difference of each pile foundation.

5. The construction method of photovoltaic cast-in-place pile according to claim 1, characterized in that: Obtain the pile top elevation of each string group, including: controlling the pile top elevations in the same string group to be in the same plane.

6. The construction method of photovoltaic cast-in-place pile according to claim 1, characterized in that: Obtaining the pile top elevation of each string group includes: controlling the pile top height difference of adjacent brackets between adjacent strings to be less than 200 mm.

7. The construction method of photovoltaic cast-in-place pile according to claim 1, characterized in that: The construction of the cast-in-place piles includes: Drilling and cleaning holes: positioning and marking the designed pile foundation points, drilling and cleaning holes; Steel cage installation; Install the casing; Concrete pouring; Install embedded parts, wherein the embedded parts are U-shaped bolts; Curing of concrete.

8. The construction method of photovoltaic cast-in-place pile according to claim 7, characterized in that: The drilling and hole cleaning process includes: performing rotary drilling according to the site level elevation of each pile foundation to make the exposed height of the front column pile body and the rear column pile body of the same group of strings equal; after drilling with a rotary drilling machine, manually cleaning the hole.

9. The construction method of photovoltaic cast-in-place pile according to claim 7, characterized in that: During the concrete pouring process, the pile foundation is formed by pouring in one time.

10. The construction method of photovoltaic cast-in-place pile according to claim 7, characterized in that: The distance between the installation position of the steel cage and the sleeve is 3.2 cm to 3.5 cm.

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