Construction method for eliminating side friction of pile foundation

Abstract

The application discloses a pile foundation side friction elimination construction method, which comprises the following steps: firstly, after the reinforcement cage is processed, the inner protection wall is wrapped outside the empty pile section of the reinforcement cage, the inner protection wall is formed by overlapping galvanized iron sheets; secondly, the anti-seepage layer is wrapped outside the inner protection wall, the anti-seepage layer is formed by overlapping a plurality of polypropylene coiled materials; thirdly, the outer protection wall is wrapped outside the empty pile section of the reinforcement cage, the outer protection wall is formed by overlapping galvanized iron sheets; fourthly, the rubber waterstop is installed between the top and bottom of the inner protection wall and the outer protection wall; fifthly, the reinforcement cage is hoisted and lowered; sixthly, the concrete is poured into the reinforcement cage; seventhly, the pile foundation is maintained; and finally, the pile foundation static load test is conducted. The material of the application is simple, the cost is low, the galvanized iron sheet and the polypropylene coiled material can be simply and quickly wrapped outside the pile foundation reinforcement cage through the profiling support frame and the jack supporting the horizontally-laid pile foundation reinforcement cage on the ground, the number of personnel required when wrapping the inner protection wall, the outer protection wall and the anti-seepage layer is reduced, and the construction efficiency is improved.

Description

A construction method for eliminating side friction of pile foundation Technical Field

[0001] This invention relates to the field of static load testing technology for bored cast-in-place friction piles, specifically to a construction method for eliminating side friction of pile foundations. Background Technology

[0002] Drilled piles are widely used in the foundation design of various building projects because they can adapt to various geological conditions and the equipment is relatively simple to invest in and operate. Some existing projects use friction piles due to the special geological conditions of the underlying soil. Due to site limitations, empty pile sections inevitably appear during the pile formation process. Since there is frictional resistance between the empty pile sections and the soil, it will have an adverse effect on the static load test of the drilled friction piles, affecting the accuracy of the static load test.

[0003] In existing pile foundation construction, a structure of adding double casings to the outside of the empty pile section is usually adopted to eliminate the side friction of the pile. However, the construction cost of the double casing structure is relatively high, and it needs to be customized according to the size of the empty pile section. Some double casing structures are also relatively complex and are easily damaged during on-site installation. Moreover, when installing the double casing, it is necessary to erect the double casing and the pile foundation reinforcement cage at the same time so that the double casing can be completely fitted into the pile foundation reinforcement cage, which makes the installation and construction difficult.

[0004] Therefore, methods such as wrapping the pile side with asphalt felt are used to eliminate pile side friction. However, the asphalt felt is easily damaged and fails during the construction process, causing the static load test results to deviate from the actual situation. Therefore, how to reduce or even eliminate pile side friction through simple and effective methods is still a problem worth studying in the engineering field. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a construction method for eliminating side friction of pile foundations.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A construction method for eliminating side friction of pile foundations includes the following steps:

[0008] S1: After the steel cage is processed, the inner protective wall is wrapped around the outside of the empty pile section of the steel cage with the help of a contour support frame. The inner protective wall is made of galvanized iron sheets.

[0009] S2: An impermeable layer is wrapped around the outer side of the inner protective wall by means of the contour support frame. The impermeable layer is made of several polypropylene rolls overlapping each other, and the overlaps of adjacent polypropylene rolls are staggered from the overlaps of adjacent galvanized iron sheets.

[0010] S3: The outer protective wall is wrapped around the empty pile section of the steel cage with the help of the contour support frame, and the outer protective wall is formed by overlapping galvanized iron sheets;

[0011] S4: Install a rubber waterstop strip between the top and bottom of the inner protective wall and the outer protective wall;

[0012] S5: Lift and lower the steel cage, pour concrete into the steel cage, carry out pile foundation curing, and finally conduct a static load test on the pile foundation.

[0013] This invention reduces the friction coefficient between the inner and outer retaining walls by incorporating a polypropylene impermeable layer in both the inner and outer retaining walls. This allows the outer retaining wall to separate from the inner retaining wall, ensuring that the empty pile section has no contact with the surrounding soil during static load testing of the pile foundation. Furthermore, the pile body can slide relative to the outer retaining wall, effectively reducing the adverse effects of pile side friction on the static load test and ensuring the accuracy of the static load test results. This, in turn, provides a reliable basis for subsequent engineering pile construction.

[0014] To prevent concrete from overflowing during the pouring of the pile foundation reinforcement cage, the seepage-proof layer is provided between the inner and outer retaining walls. When concrete overflows from the inner retaining wall, it will be blocked by the seepage-proof layer, preventing the inner and outer retaining walls from being bonded together by the overflowing concrete. This avoids the pile side friction from having an adverse effect on the static load test of the pile foundation through the inner and outer retaining walls.

[0015] The inner and outer protective walls are made of overlapping galvanized iron sheets, and the seepage-proof layer is made of polypropylene rolls. The materials are simple and the cost is low. Since the galvanized iron sheets and polypropylene rolls are both lightweight, the pile foundation reinforcement cage can be lifted directly using conventional methods when it is placed into the borehole, without worrying about the inner and outer protective walls or the seepage-proof layer being too heavy.

[0016] Preferably, the wrapping process of the inner protective wall and the outer protective wall is as follows:

[0017] S1.1: Place the empty pile section of the steel cage onto the contour support frame, and lift the steel cage with jacks on both sides of the contour support frame;

[0018] S1.2: Insert the first galvanized iron sheet into the lower half of the reinforcing cage, and wrap the upper half of the reinforcing cage with the second galvanized iron sheet. The two ends of the second galvanized iron sheet are inserted between the reinforcing cage and the contour support frame. The first galvanized iron sheet and the second galvanized iron sheet overlap each other by a distance of not less than 15cm.

[0019] S1.3: Operate the jack to lower the steel cage, close the clamp-shaped guard arms on both sides of the contour support frame, and fix the overlapping parts of the first galvanized iron sheet and the second galvanized iron sheet together to form a protective wall section;

[0020] S1.4: Open the clamp-shaped guard arm, lift the steel cage with the jack, move the contour support frame so that the distance between the wall sections within the contour support frame is 30cm to 50cm, and then complete the wrapping of the other wall section in sequence according to steps S1.1, S1.2 and S1.3. Finally, fix the overlapping parts of the adjacent wall sections together.

[0021] S1.5: Repeat step S1.4 until the empty pile segment is completely wrapped by the retaining wall segment, forming the inner retaining wall or the outer retaining wall.

[0022] Preferably, the process of wrapping the impermeable layer is as follows:

[0023] S2.1: Place the empty pile section of the steel cage onto the contour support frame, and lift the steel cage with jacks on both sides of the contour support frame;

[0024] S2.2: Wrap a section of the reinforcing cage with polypropylene roll material through the gap between the reinforcing cage and the contour support frame;

[0025] S2.3: Operate the jack to lower the steel cage, close the clamp-shaped guard arms on both sides of the contour support frame, overlap and fix the end of the polypropylene roll wrapped around the steel cage to form a seepage-proof section;

[0026] S2.4: Open the clamp-shaped protective arm, lift the steel cage with the jack, move the contour support frame so that the distance between the seepage prevention section and the contour support frame is 30cm to 50cm, and then complete the wrapping of the other seepage prevention section in sequence according to steps S2.1, S2.2 and S2.3. Finally, fix the overlapping parts of the adjacent seepage prevention sections together.

[0027] S2.5: Repeat step S2.4 until the empty pile section is completely covered by the seepage-proof section, forming the seepage-proof layer.

[0028] This invention utilizes the contour support frame and jacks to support the pile foundation reinforcement cage lying horizontally on the ground, allowing the galvanized iron sheet and the polypropylene roll to be easily and quickly wrapped around the outside of the pile foundation reinforcement cage. At the same time, the clamp-shaped guard arm helps to fix the galvanized iron sheet or the polypropylene roll that has not yet been wrapped and overlapped, reducing the number of personnel required to wrap the inner wall, the outer wall, and the seepage prevention layer, and speeding up the construction efficiency.

[0029] Preferably, the contour support frame includes a base, a support plate, and a clamp-shaped guard arm. The bottom of the base is provided with casters, and the base is provided with at least one pair of support plates. The support plate has a groove in the middle to accommodate the steel cage. The clamp-shaped guard arm includes a pair of arc-shaped plates. One end of the arc-shaped plate is rotatably connected to the support plate, and the other end is in contact with the adjacent arc-shaped plate.

[0030] Preferably, the clamp-shaped guard arm further includes a fastening device, which includes a fixing seat and a fixing bolt. The fixing seat and the fixing bolt are connected by a threaded connection, and the fixing seat and the fixing bolt are respectively disposed on the two arc-shaped plates.

[0031] When the clamp-shaped guard arm is closed, in order to tightly wrap the galvanized iron sheet or the polypropylene coil around the reinforcing cage, a pair of arc-shaped plates are fixed together by the fastening device, and pressure is applied to the galvanized iron sheet or the polypropylene coil by the clamp-shaped guard arm.

[0032] Preferably, the thickness of the galvanized iron sheet is 0.4mm to 0.7mm, and the gaps at the overlaps of the galvanized iron sheet are sealed with sealing strips to prevent concrete from overflowing from the gaps at the overlaps of the galvanized iron sheet during concrete pouring. The galvanized iron sheet has a certain rigidity to ensure the forming quality of the concrete poured into the empty pile section.

[0033] Preferably, the galvanized iron sheets are fixed together with screws, and the spacing between adjacent screws is 10cm to 20cm.

[0034] Preferably, the distance between the overlapping portions of adjacent retaining wall sections is not less than 15cm, and the distance between the overlapping portions of adjacent seepage prevention sections is not less than 15cm.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] (1) The present invention adopts a polypropylene anti-seepage layer in the inner and outer protective walls to reduce the friction coefficient between the inner and outer protective walls, so that the outer protective wall is separated from the inner protective wall. When the pile foundation is subjected to static load test, the empty pile section of the pile body has no contact with the surrounding soil, and the pile body can slide relative to the outer protective wall, which effectively reduces the adverse effects of pile side friction on the static load test of the pile foundation, ensures the accuracy of the static load test results, and thus provides a reliable basis for subsequent engineering pile construction.

[0037] (2) In order to prevent the concrete from overflowing during the concrete pouring of the pile foundation reinforcement cage, the present invention sets an anti-seepage layer between the inner and outer protective walls. When the concrete overflows from the inner protective wall, it will be blocked by the anti-seepage layer, preventing the inner and outer protective walls from being bonded together by the overflowing concrete, thus avoiding the adverse effects of the pile side friction on the static load test of the pile foundation through the inner and outer protective walls.

[0038] (3) The inner and outer protective walls of the present invention are made of galvanized iron sheets overlapping, and the seepage prevention layer is made of polypropylene rolls. The materials are simple and the cost is low. At the same time, the present invention uses a contour support frame and jacks to support the pile foundation steel cage lying horizontally on the ground, so that the galvanized iron sheets and polypropylene rolls can be wrapped on the outside of the pile foundation steel cage simply and quickly. Meanwhile, the clamp-shaped guard arm is used to help fix the galvanized iron sheets or polypropylene rolls that have not yet been wrapped and overlapped, which reduces the number of personnel required when wrapping the inner and outer protective walls and the seepage prevention layer, and speeds up the construction efficiency.

[0039] (4) Since galvanized iron sheet and polypropylene roll are both relatively light, the pile foundation steel cage can be lifted directly using conventional methods when it is placed into the borehole, without worrying about the inner and outer protective walls or seepage prevention layer being too heavy. Attached Figure Description

[0040] Figure 1 is a schematic diagram of the structure of the present invention during static load testing;

[0041] Figure 2 is a magnified view of part A in Figure 1;

[0042] Figure 3 is a schematic diagram of the structure of the steel cage placed on the contour support frame when the clamp-shaped guard arm is closed in this invention.

[0043] Figure 4 is a schematic diagram of the steel cage placed on the contour support frame when the clamp-shaped guard arm is opened in this invention.

[0044] Figure 5 is a schematic diagram of the cross-sectional structure of the steel cage, inner wall, outer wall and seepage prevention layer in this invention;

[0045] Figure 6 is a schematic diagram of step S1.1 in this invention;

[0046] Figure 7 is a schematic diagram of step S1.3 in this invention;

[0047] Figure 8 is a schematic diagram of step S1.4 in this invention;

[0048] In the diagram: 1. Reinforcing cage; 2. Contour support frame; 3. Jack; 4. Inner wall; 5. Anti-seepage layer; 6. Outer wall; 7. Rubber waterstop strip; 8. Pliers-shaped guard arm. Detailed Implementation

[0049] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In the description of this invention, it should be noted that the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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 this invention.

[0051] As shown in Figures 1-8, the specific scheme of the embodiment is as follows: A construction method for eliminating side friction of pile foundation includes the following steps:

[0052] S1: After the steel cage 1 is processed, the inner wall 4 is wrapped around the outside of the empty pile section of the steel cage 1 with the help of the contour support frame 2. The inner wall 4 is made of galvanized iron sheet.

[0053] S2: The seepage-proof layer 5 is wrapped around the outside of the inner wall 4 with the help of the contour support frame 2. The seepage-proof layer 5 is made of several polypropylene rolls overlapping each other. The overlap of adjacent polypropylene rolls is staggered from the overlap of adjacent galvanized iron sheets.

[0054] S3: The outer retaining wall 6 is wrapped around the empty pile section of the steel cage 1 with the help of the contour support frame 2. The outer retaining wall 6 is made of galvanized iron sheets.

[0055] S4: Install rubber waterstop strips 7 between the top and bottom of the inner protective wall 4 and the outer protective wall 6;

[0056] S5: Lift and lower the steel cage 1, pour concrete into the steel cage 1, carry out pile foundation curing, and finally conduct a static load test on the pile foundation.

[0057] Specifically, during the static load test of the pile foundation, the empty pile section is not in contact with the surrounding soil, and the outer retaining wall 6 is in close contact with the soil around the empty pile section. When the pile foundation is under pressure, the impermeable layer 5 reduces the friction coefficient between the inner and outer retaining walls. Therefore, when the pile moves downward, the pile body drives the inner retaining wall 4 and the impermeable layer 5 to slide relative to the outer retaining wall 6, which effectively reduces the frictional resistance on the pile side.

[0058] Specifically, the top of the empty pile section of steel cage 1 is level with the ground leveling elevation, and the bottom of the empty pile section of steel cage 1 is level with the bottom of the pile cap.

[0059] Specifically, the wrapping process of the inner protective wall 4 and the outer protective wall 6 is as follows:

[0060] S1.1: Place the empty pile section of the steel cage 1 onto the contour support frame 2, and lift the steel cage 1 with jacks 3 on both sides of the contour support frame 2;

[0061] S1.2: Insert the first galvanized iron sheet into the lower half of the reinforcing cage 1, and wrap the upper half of the reinforcing cage 1 with the second galvanized iron sheet. Insert both ends of the second galvanized iron sheet between the reinforcing cage 1 and the contour support frame 2. The overlap distance between the first galvanized iron sheet and the second galvanized iron sheet is controlled at 20cm.

[0062] S1.3: Operate jack 3 to lower steel cage 1, close the clamp-shaped guard arms 8 on both sides of the contour support frame 2, and fix the overlapping part of the first galvanized iron sheet and the second galvanized iron sheet together to form a protective wall section.

[0063] S1.4: Open the clamp-shaped guard arm 8, lift the steel cage 1 with the jack 3, move the contour support frame 2 so that the distance between the wall section and the contour support frame 2 is 40cm, and then follow steps S1.1, S1.2 and S1.3 to complete the wrapping of another wall section. Finally, fix the overlapping parts of the adjacent wall sections together.

[0064] S1.5: Repeat step S1.4 until the empty pile section is completely enclosed by the retaining wall section, forming the inner retaining wall 4 or the outer retaining wall 6.

[0065] Specifically, the top and bottom of the inner retaining wall 4 extend beyond the empty pile section, making the height of the inner retaining wall 4 greater than the height of the empty pile section. The height of the empty pile section is the same as the height of the seepage prevention layer 5 and the outer retaining wall 6.

[0066] Specifically, the process of wrapping the impermeable layer 5 is as follows:

[0067] S2.1: Place the empty pile section of the steel cage 1 onto the contour support frame 2, and use jacks 3 to lift the steel cage 1 on both sides of the contour support frame 2.

[0068] S2.2: Wrap a section of the reinforcing cage 1 with polypropylene rolls through the gap between the reinforcing cage 1 and the contour support frame 2;

[0069] S2.3: Use jack 3 to lower the steel cage 1, close the clamp-shaped guard arms 8 on both sides of the contour support frame 2, and overlap and fix the end of the polypropylene roll wrapped around the steel cage 1 to form a seepage-proof section.

[0070] S2.4: Open the clamp-shaped protective arm 8, lift the steel cage 1 with the jack 3, move the contour support frame 2 so that the distance between the seepage prevention section and the contour support frame 2 is 40cm, and then complete the wrapping of the other seepage prevention section in sequence according to steps S2.1, S2.2 and S2.3. Finally, fix the overlapping parts of the adjacent seepage prevention sections together.

[0071] S2.5: Repeat step S2.4 until the empty pile section is completely covered by the seepage-proof section, forming the seepage-proof layer 5.

[0072] Specifically, the steel cage 1 is supported by several jacks 3 according to its length, and the jacks 3 support the steel cage 1 through a guard plate. The guard plate has a groove in the middle to prevent the steel cage 1 from tilting due to uneven force. When the contour support frame 2 needs to be moved, multiple jacks 3 can also cooperate with each other to move the position of some jacks 3, leaving room for the contour support frame 2 to move.

[0073] Specifically, the overlapping sections of adjacent inner and outer retaining walls are staggered from the overlapping sections of adjacent seepage-proof sections, and the distance between the two sections is not less than 400mm.

[0074] Specifically, after moving the contour support frame 2 in steps S1.4 and S2.4, the area that needs to be wrapped as a protective wall section or a seepage prevention section should be located in the middle of a pair of support plates.

[0075] Specifically, the contour support frame 2 includes a base, a support plate, and a clamp-shaped guard arm 8. The bottom of the base is provided with casters, and the base is provided with at least one pair of support plates. The support plate has a groove in the middle to accommodate the steel cage 1. The clamp-shaped guard arm 8 includes a pair of arc plates, one end of which is rotatably connected to the support plate, and the other end is in contact with the adjacent arc plate.

[0076] Specifically, when wrapping the empty pile section to form a retaining wall section, the retaining wall section should be located in the middle of a pair of support plates. When fixing the first galvanized iron sheet and the second galvanized iron sheet, the overlapping parts of the first galvanized iron sheet and the second galvanized iron sheet are fixedly connected with screws. When fixing adjacent retaining wall sections, the overlapping parts around the adjacent retaining wall sections are fixedly connected with screws.

[0077] Specifically, when wrapping the inner wall 4, the overlapping parts of the polypropylene roll are fixedly connected by waterproof tape, and the distance between the overlapping parts of the polypropylene roll is not less than 15cm. When fixing adjacent seepage prevention sections, the overlapping parts around the adjacent seepage prevention sections are fixedly connected by waterproof tape.

[0078] Specifically, the clamp-shaped guard arm 8 also includes a fastening device, which includes a fixing seat and a fixing bolt. The fixing seat and the fixing bolt are connected by a threaded connection, and the fixing seat and the fixing bolt are respectively located on two arc-shaped plates.

[0079] Specifically, the fixed seat is provided with screw holes, and the fixing bolt includes a bolt and a support. The bolt and the support are connected by threads, and the support is set on an arc plate. When the clamp-shaped guard arm 8 is closed, the bolt is aligned with the screw hole on the fixed seat and screwed into the screw hole. The arc plate with the fixed seat is connected to the arc plate with the support by the bolt.

[0080] Specifically, the thickness of the galvanized iron sheet is 0.5mm, and the gaps at the overlaps of the galvanized iron sheet are sealed with sealing strips.

[0081] Specifically, the galvanized iron sheets are fixed together with screws, with a spacing of 15cm between adjacent screws.

[0082] Specifically, when fixing the galvanized iron sheet of the outer sheath 6 with screws, the depth of the screws into the galvanized iron sheet should be controlled to avoid damaging the integrity of the polypropylene roll.

[0083] Specifically, the distance between the overlapping parts of adjacent retaining wall sections is 20cm, and the distance between the overlapping parts of adjacent seepage prevention sections is also 20cm.

[0084] Specifically, the rubber waterstop strip 7 is a low-friction sealing strip. The rubber waterstop strip 7 is inserted between the inner protective wall 4 and the outer protective wall 6. The rubber waterstop strip 7 is glued to the outer protective wall 6 with high-strength adhesive.

[0085] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A construction method for eliminating side friction of pile foundations, characterized in that: Includes the following steps: S1: After the reinforcing cage is processed, an inner protective wall is wrapped around the outside of the empty pile section of the reinforcing cage using a contoured support frame. The inner protective wall is made of overlapping galvanized iron sheets. S2: A seepage-proof layer is wrapped around the outside of the inner protective wall using the contoured support frame. The seepage-proof layer is made of overlapping polypropylene rolls, with the overlaps of adjacent polypropylene rolls staggered from the overlaps of adjacent galvanized iron sheets. S3: An outer protective wall is wrapped around the outside of the empty pile section of the reinforcing cage using the contoured support frame. The outer protective wall is made of overlapping galvanized iron sheets. S4: At the top of the inner and outer protective walls... S5: Install rubber waterstop strips between the bottom and top; S6: Lift and lower the reinforcing cage, pour concrete into the reinforcing cage, carry out pile foundation curing, and finally conduct pile foundation static load test; The wrapping process of the inner and outer protective walls is as follows: S1.1: Place the empty pile section of the reinforcing cage on the contour support frame, and lift the reinforcing cage with jacks on both sides of the contour support frame; S1.2: Insert the first galvanized iron sheet into the lower half of the reinforcing cage, wrap the upper half of the reinforcing cage with the second galvanized iron sheet, and insert both ends of the second galvanized iron sheet between the reinforcing cage and the contour support frame. The first galvanized iron sheet and the second galvanized iron sheet overlap by a distance of not less than 15cm; S1.3: Use the jack to lower the reinforcing cage, close the clamp-shaped guards on both sides of the contour support frame, and fix the overlapping parts of the first galvanized iron sheet and the second galvanized iron sheet together to form a protective wall section; S1.4: Open the clamp-shaped guards, use the jack to lift the reinforcing cage, move the contour support frame so that the distance between the protective wall section and the contour support frame is 30cm~50cm, and then complete the other step according to steps S1.1, S1.2 and S1.3 in sequence. The wall protection section is wrapped, and finally the overlapping parts of the adjacent wall protection sections are fixed together; S1.5: Repeat step S1.4 until the empty pile section is completely wrapped by the wall protection section to form the inner wall protection or the outer wall protection; The contour support frame includes a base, a support plate and a clamp-shaped guard arm. The bottom of the base is provided with universal wheels. The base is provided with at least one pair of support plates. The support plate is provided with a groove in the middle to accommodate the steel cage. The clamp-shaped guard arm includes a pair of arc plates. One end of the arc plate is rotatably connected to the support plate and the other end is in contact with the adjacent arc plate.

2. The method for eliminating side friction of pile foundations according to claim 1, characterized in that... The process of wrapping the seepage-proof layer is as follows: S2.1: Place the empty pile section of the reinforcing cage onto the contour support frame, and lift the reinforcing cage using jacks on both sides of the contour support frame; S2.2: Wrap a section of the reinforcing cage with polypropylene roll material through the gap between the reinforcing cage and the contour support frame; S2.3: Lower the reinforcing cage using the jacks, close the clamp-shaped guards on both sides of the contour support frame, overlap and fix the ends of the polypropylene roll material wrapping the reinforcing cage to form the seepage-proof section. S2.4: Open the clamp-shaped protective arm, lift the steel cage with the jack, move the contour support frame so that the distance between the seepage-proof sections within the contour support frame is 30cm~50cm, then follow steps S2.1, S2.2 and S2.3 to complete the wrapping of the other seepage-proof section in sequence, and finally fix the overlapping parts of the adjacent seepage-proof sections together; S2.5: Repeat step S2.4 until the empty pile section is completely wrapped by the seepage-proof section to form the seepage-proof layer.

3. The method for eliminating side friction of pile foundations according to claim 1, characterized in that: The clamp-shaped guard arm also includes a fastening device, which includes a fixing seat and a fixing bolt. The fixing seat and the fixing bolt are connected by a threaded connection, and the fixing seat and the fixing bolt are respectively provided on the two arc-shaped plates.

4. The method for eliminating side friction of pile foundations according to claim 1, characterized in that... The thickness of the galvanized iron sheet is 0.4mm~0.7mm, and the gaps at the overlaps of the galvanized iron sheet are sealed with sealing strips.

5. The method for eliminating side friction of pile foundations according to claim 1, characterized in that... The galvanized iron sheets are fixed together with screws, and the spacing between adjacent screws is 10cm to 20cm.

6. The method for eliminating side friction of pile foundations according to claim 1, characterized in that... The distance between the overlapping portions of adjacent retaining wall sections shall not be less than 15cm.

7. The method for eliminating side friction of pile foundations according to claim 2, characterized in that... The distance between the overlapping portions of adjacent seepage-proof sections shall not be less than 15cm.

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