Combined cement-soil mixing pile anti-seepage structure and construction method thereof

Abstract

The invention provides a combined cement-soil mixing pile anti-seepage structure and a construction method thereof.The anti-seepage structure is used for reinforcing, lifting and transforming a dike, the anti-seepage capacity and stability of the dike are improved through combined construction of cement-soil mixing piles and steel sheet piles, connection of the steel sheet piles is achieved through H-shaped steel, and the anti-seepage performance of the dike is improved. And meanwhile, position parameters of the steel sheet piles, the H-shaped steel and the cement mixing piles are reasonably designed, optimization of an anti-seepage reinforcing structure of the dike is achieved, a reasonable construction method is designed, and anti-seepage reinforcing of the dike is achieved.

Description

[0001] Technical field: The present invention relates to the field of water conservancy projects, and in particular to a combined cement-soil mixing pile anti-seepage structure and a construction method thereof.

[0002] Background: Channels are the most common structural form of water conservancy projects. By constructing channels, water can be diverted and adjusted to meet the rational allocation of water resources. Channel embankments play an important role in ensuring the structural stability and proper function of channels. Generally, channels are made of earth. Long-term water seepage can lead to structural damage to channel embankments. In severe cases, this can even cause the embankment to fail, leading to embankment breaches and resulting in water disasters.

[0003] Reinforcement of embankments is an important measure to ensure the normal and safe operation of embankments. Conventional embankment reinforcement mostly uses grouting, anti-seepage walls, etc., which have limited reinforcement effects on embankments, especially for embankment sections with obvious seepage and high embankment seepage coefficients. A single reinforcement method cannot effectively guarantee the reinforcement of the embankment. If only a single reinforcement is used, the input-output ratio is relatively low. For example, if only an anti-seepage wall is used, if the depth and thickness are large, it will cause an increase in project investment costs. On the contrary, if the depth and thickness do not meet the requirements, the reinforcement effect will not meet expectations.

[0004] Summary of the invention: In view of the problems of the prior art, the present invention provides a combined cement-soil mixing pile anti-seepage structure and a construction method thereof, constructs a combined reinforcement construction for the embankment, and comprehensively improves the reinforcement and maintenance effect of the embankment.

[0005] The present invention provides a combined cement-soil mixing pile anti-seepage structure, which is used for embankment reinforcement and is characterized in that: the anti-seepage structure includes a cement-soil mixing pile located in the middle of the embankment and a steel sheet pile located at the foot of the slope on the water side of the embankment, the steel sheet piles are connected by H-shaped steel, the middle part of the steel sheet pile is a straight section, and an upper U-shaped opening and a lower U-shaped opening are respectively provided at both ends, the upper flange and the lower flange of the H-shaped steel are respectively snap-connected with the upper U-shaped opening and the lower U-shaped opening of the steel sheet pile, the depth of the cement-soil mixing pile corresponding to the straight section of the steel sheet pile is greater than the depth ΔH of the steel sheet pile, and the ΔH is not less than 1 / 10 of the distance between the steel sheet pile and the cement-soil mixing pile, the cement-soil mixing pile corresponding to the H-shaped steel is a reinforcement section, the length of the reinforcement section is not less than twice the length of the H-shaped steel, and the depth of the reinforcement section is greater than the depth 2ΔH of the steel sheet pile.

[0006] Preferably, the distance between the steel sheet pile and the cement soil mixing pile is the distance between the center lines of the steel sheet pile and the cement soil mixing pile, and the length of the H-shaped steel is the distance between the top of the upper flange and the bottom of the lower flange of the H-shaped steel.

[0007] Preferably, the upper U-shaped opening and the lower U-shaped opening are respectively adapted to the sizes of the upper flange and the lower flange of the H-shaped steel.

[0008] Preferably, the amount of cement in the cement-soil mixing pile is 15% of the mass of the soil, and the water-cement ratio is 1.0.

[0009] A construction method for the combined cement-soil mixing pile anti-seepage structure as described above is characterized in that the construction method comprises the following steps:

[0010] S1: Construction is carried out during a dry period. The site is cleaned at the foot of the waterside slope of the embankment, the position of the steel sheet piles is located, and the line is laid out on site. Then, the guide frame is erected on site.

[0011] S2: transport the steel sheet piles and H-shaped steel to the site, use a crane to lift the steel sheet piles and H-shaped steel into the pile insertion points, and connect the upper and lower flanges of the H-shaped steel to the upper and lower U-shaped openings of the steel sheet piles respectively;

[0012] S3: Steel sheet piles and H-beams are driven in multiple stages. When the top of the steel sheet piles and H-beams is less than 1m from the ground, the guide frame is removed and the steel sheet piles and H-beams are driven to the designed elevation. After all the steel sheet piles and H-beams are driven in, the site is cleaned up.

[0013] S4: Use machinery to break up the concrete pavement of the original embankment road, clean and level the construction site with manual labor and machinery, and use an excavator to dig a guide ditch along the axis of the cement-soil mixing pile;

[0014] S5: Positioning and laying out, the pile driver is in place, soil, cement and water are mixed in proportion in the slurry tank, the mixed slurry is pumped into the slurry storage tank, and stirred continuously to make it uniform and stable. The slurry should be screened when it is pumped into the slurry storage tank;

[0015] S6: Start the pile driver. After the rotating speed of the mixing drill bit is normal, sink the drill rod while stirring. After sinking to the designed depth, start the mortar pump to deliver slurry to the slurry outlet of the mixing drill bit through the pipeline. After the slurry is discharged, start the pile driver. Slurry is sprayed and stirred while the drill rod is lifted at the lifting speed determined by the design to fully mix the slurry and soil.

[0016] S7: After the mixing drill bit is lifted to a height of 500mm above the pile top, the mortar pump is turned off and the mortar is stirred and sunk to the designed depth. After sinking to the designed depth, the mortar is sprayed and mixed and lifted until the pile is formed;

[0017] S8: The pile driver moves to the next pile position and repeats steps S6-S7 until the construction of all cement-soil mixing piles is completed.

[0018] Preferably, when laying out the S5, the depth of the corresponding cement soil mixing pile is determined based on the position of the steel sheet pile and the H-shaped steel, and the cement soil mixing pile in the reinforcement section is specially marked. When constructing the cement soil mixing pile in the reinforcement section, the construction is carried out according to the preset depth.

[0019] The working principle of the present invention is as follows:

[0020] Cement-soil mixing piles are an important structural form of anti-seepage wall for embankment reinforcement. They form a continuous anti-seepage wall, which prevents leakage and damage to the embankment. However, if only a single cement-soil mixing pile anti-seepage wall is used, the wall's depth and thickness must be high. Furthermore, if only a single cement-soil mixing pile anti-seepage wall is used, any localized leakage could affect the overall safety of the embankment structure. If double or multiple rows of cement-soil mixing piles are used, the construction cost of the anti-seepage reinforcement increases because the wall structure is constructed from the top of the embankment. Furthermore, the limited working space on the embankment makes the construction of double or multiple rows of cement-soil mixing piles unfavorable.

[0021] The combined cement-soil mixing pile anti-seepage reinforcement structure provided by the present invention adopts a combination of a cement-soil mixing pile anti-seepage wall on the top of the embankment and a steel sheet pile at the foot of the slope on the water side. It is suitable for sections where leakage and damage to the embankment are serious. The steel sheet piles are permanently fixed to the foot of the slope to form a first anti-seepage barrier. When the water flow on the water side is deep, the seepage pressure of the foundation of the embankment is also large. The anti-seepage barrier of the steel sheet piles prolongs the seepage path, which can greatly reduce the anti-seepage pressure of the embankment foundation. At the same time, the steel sheet piles are combined with the cement-soil mixing pile anti-seepage wall to effectively achieve combined anti-seepage and reduce the depth of the cement-soil mixing pile anti-seepage wall. In the present invention, the depth of the cement-soil mixing pile anti-seepage wall is greater than the depth of the steel sheet piles (both bottom height The selection of ΔH should be determined in combination with the setting form of the embankment, specifically not less than 1 / 10 of the distance between the steel sheet pile and the cement soil mixing pile. The distance between the steel sheet pile and the cement soil mixing pile is the distance of seepage from the steel sheet pile to the cement soil mixing pile, that is, the distance between the first anti-seepage barrier and the second anti-seepage barrier. Taking 10% of this distance can generally meet the double anti-seepage blocking effect and play the anti-seepage combination function. If the depth of the cement soil mixing pile is small, the seepage will move upward behind the steel sheet pile, which is not conducive to anti-seepage. Through this setting form, the safety of seepage can be effectively protected. The distance should be the distance from the center line of the steel sheet pile to the outer center line of the cement soil mixing pile.

[0022] During the construction of steel sheet piles, the construction difficulty is relatively small. Considering that they are only set up in sections with serious leakage, their working surface is small, and guide frame construction is selected. The steel sheet piles are connected by H-shaped steel, wherein the upper and lower edges of the H-shaped steel respectively cooperate with the upper U-shaped mouth and the lower U-shaped mouth of the steel sheet pile. Through this setting method, the setting of straight web type steel sheet piles can be realized, thereby improving construction efficiency. The upper and lower flanges of the H-shaped steel respectively cooperate with the upper U-shaped mouth of the previous steel sheet pile and the lower U-shaped mouth of the next steel sheet pile. The length and height of the steel sheet pile can be adjusted. Generally, the length can be 3 to 5 times the height, which can greatly improve construction efficiency while ensuring the anti-seepage effect and connection performance of the steel sheet pile.

[0023] For the H-shaped steel section, the length of the web can be appropriately lengthened, generally 0.5 to 2 times the height of the steel sheet pile. The H-shaped steel can play the anti-seepage function of the steel sheet pile, and can also play a connecting role to ensure the stress integrity of the steel sheet pile section. A reinforcement section should be set at the cement-soil mixing pile corresponding to the H-shaped steel. The length of the reinforcement section shall not be less than 2 times the length of the H-shaped steel, and the depth of the reinforcement section shall be greater than the depth of the steel sheet pile 2ΔH. By setting the reinforcement section, leakage damage in the H-shaped steel connection section can be avoided, and the overall strength and stress of the structure can be ensured.

[0024] The advantages of the present invention are:

[0025] The present invention provides a combined cement-soil mixing pile anti-seepage structure and a construction method thereof. Through reasonable structural design, it can exert a dual anti-seepage reinforcement effect. At the same time, the construction method is reasonable and can improve construction efficiency. Its advantages include:

[0026] (1) Using steel sheet piles and cement-soil mixing piles to form a double anti-seepage reinforcement can strengthen and maintain the embankment section with serious leakage, thereby improving the overall protection effect of the embankment;

[0027] (2) Using the H-shaped steel connection component design, the H-shaped steel and steel sheet piles are effectively connected to prevent leakage and damage at the interface, and the straight web setting and construction of the H-shaped steel and steel sheet piles are realized, thereby improving construction efficiency;

[0028] (3) Reinforcement sections are set at the locations of the cement-soil mixing piles corresponding to the H-shaped steel, and the reinforcement sections are used to improve the anti-seepage protection effect of the anti-seepage wall;

[0029] (4) First construct the steel sheet piles and H-shaped steel, then mark the position of the cement soil mixing pile reinforcement section, and then construct the cement soil mixing piles. Rationally design and calculate the depth of the steel sheet piles and cement soil mixing piles to achieve orderly operation. Description of the drawings:

[0030] Figure 1 It is a structural schematic diagram of the present invention;

[0031] Figure 2 This is a schematic diagram of the steel sheet pile structure;

[0032] Figure 3 This is a schematic diagram of the H-shaped steel structure;

[0033] Figure 4 This is a schematic diagram of the connection between steel sheet piles and H-beams;

[0034] Figure 5 This is a schematic diagram of the location of the H-steel connection section and the cement-soil mixing pile reinforcement section;

[0035] Figure 6 Flow chart of the construction method of the present invention;

[0036] Figure 7 This is a schematic diagram of the construction process of cement-soil mixing piles.

[0037] Specific implementation method: The following is a detailed explanation of the content defined in the present invention.

[0038] The present invention provides a combined cement-soil mixing pile 1 anti-seepage structure, which is used for embankment reinforcement and is characterized in that: the anti-seepage structure includes a cement-soil mixing pile 1 located in the middle of the embankment and a steel sheet pile 2 located at the foot of the slope on the water side of the embankment, the steel sheet pile 2 is connected by an H-shaped steel 3, the middle part of the steel sheet pile 2 is a straight section, and an upper U-shaped opening 21 and a lower U-shaped opening 22 are respectively provided at both ends, the upper flange 31 and the lower flange 32 of the H-shaped steel 3 are respectively snap-connected with the upper U-shaped opening 21 and the lower U-shaped opening 22 of the steel sheet pile 2, the depth of the cement-soil mixing pile corresponding to the straight section of the steel sheet pile 2 is greater than the depth ΔH of the steel sheet pile 2, and the ΔH is not less than 1 / 10 of the distance between the steel sheet pile 2 and the cement-soil mixing pile, the cement-soil mixing pile corresponding to the H-shaped steel is a reinforcement section 11, the length of the reinforcement section 11 is not less than twice the length of the H-shaped steel 3, and the depth of the reinforcement section 11 is greater than the depth 2ΔH of the steel sheet pile 2.

[0039] Preferably, the distance between the steel sheet pile 2 and the cement soil mixing pile is the distance between the center lines of the steel sheet pile 2 and the cement soil mixing pile, and the length of the H-shaped steel 3 is the distance between the top of the upper flange 31 and the bottom of the lower flange 32 of the H-shaped steel 3. Figure 1 As shown in the figure, the distance between the center line of the steel sheet pile 2 and the cement soil mixing pile is S. Figure 3 The distance between the top of the upper flange 31 of the H-shaped steel 3 and the bottom of the lower flange 32 is L, and the length of the reinforcement section 11 of the cement-soil mixing pile 1 is greater than or equal to 2L. Preferably, the center line of the reinforcement section 11 of the cement-soil mixing pile 1 is the same as the center line of the H-shaped steel 3.

[0040] Preferably, the upper U-shaped opening 21 and the lower U-shaped opening 22 are respectively adapted to the sizes of the upper flange 31 and the lower flange 32 of the H-shaped steel 3, and the upper U-shaped opening 21 and the lower U-shaped opening 22 both include side walls parallel to each other and a bottom wall perpendicular to the side walls, and the distance between the side walls is respectively adapted to the thickness of the upper flange 31 and the lower flange 32 of the H-shaped steel 3.

[0041] Preferably, the amount of cement in the cement-soil mixing pile is 15% of the mass of the soil, and the water-cement ratio is 1.0. The amount of cement and the water-cement ratio can be reasonably determined through experiments.

[0042] A construction method for the combined cement-soil mixing pile 1 anti-seepage structure as described above is characterized in that the construction method comprises the following steps:

[0043] S1: Construction is carried out during a dry period. The site is cleaned at the foot of the waterside slope of the embankment, the position of the steel sheet pile 2 is located, the line is laid out on site, and then the guide frame is erected on site.

[0044] S2: transport the steel sheet pile 2 and the H-shaped steel 3 to the site, use a crane to lift the steel sheet pile 2 and the H-shaped steel 3 to the pile insertion point for insertion, and make the upper flange 31 and the lower flange 32 of the H-shaped steel 3 snap-fit ​​with the upper U-shaped opening 21 and the lower U-shaped opening 22 of the steel sheet pile 2 respectively;

[0045] S3: Steel sheet piles 2 and H-beams 3 are driven in multiple stages. When the tops of the steel sheet piles 2 and H-beams 3 are less than 1m from the ground, the guide frame is removed and the steel sheet piles 2 and H-beams 3 are driven to the designed elevation. After all the steel sheet piles 2 and H-beams 3 are driven, the site is cleaned up.

[0046] S4: Use machinery to break up the concrete pavement of the original embankment road, clean and level the construction site with manual labor and machinery, and use an excavator to dig a guide ditch along the axis of the cement-soil mixing pile;

[0047] S5: Positioning and laying out, the pile driver is in place, soil, cement and water are mixed in proportion in the slurry tank, the mixed slurry is pumped into the slurry storage tank, and stirred continuously to make it uniform and stable. The slurry should be screened when it is pumped into the slurry storage tank;

[0048] S6: Start the pile driver. After the rotating speed of the mixing drill bit is normal, sink the drill rod while stirring. After sinking to the designed depth, start the mortar pump to deliver slurry to the slurry outlet of the mixing drill bit through the pipeline. After the slurry is discharged, start the pile driver. Slurry is sprayed and stirred while the drill rod is lifted at the lifting speed determined by the design to fully mix the slurry and soil.

[0049] S7: After the mixing drill bit is lifted to a height of 500mm above the pile top, the mortar pump is turned off and the mortar is stirred and sunk to the designed depth. After sinking to the designed depth, the mortar is sprayed and mixed and lifted until the pile is formed;

[0050] S8: The pile driver moves to the next pile position and repeats steps S6-S7 until the construction of all cement-soil mixing piles is completed.

[0051] Preferably, the number of cycles of sinking and lifting (one sinking and lifting is one cycle) in S7 is 2 to 5 times.

[0052] Preferably, when laying out the S5, the depth of the corresponding cement-soil mixing pile 1 is determined based on the positions of the steel sheet pile 2 and the H-shaped steel 3, and the cement-soil mixing pile of the reinforcement section 11 is specially marked. When constructing the cement-soil mixing pile of the reinforcement section 11, the construction is carried out according to the preset depth.

[0053] In the specific implementation method, a certain embankment reinforcement project is taken as an example. The cement in the cement-soil mixing pile adopts P·O42.5 cement. The specific construction process of the cement-soil anti-seepage wall is as shown in the attached figure. Figure 7 During construction, strictly control the sinking and lifting speeds to ensure the proper amount of grouting and pile quality. Mark the drill rig with clear markings to facilitate control of drilling depth and ensure the proper time for surface mixing. Prepared cement slurry must not segregate, and the slurry supply must be continuous. If slurry is stopped for any reason, the piles must overlap by at least 0.5m. If the slurry is stopped for more than 3 hours, the prepared slurry cannot be used. The pipes must also be cleaned thoroughly.

[0054] Before construction, a cement-soil mixing pile test is first carried out to collect the following construction technical parameters: cement slurry ratio, drilling speed, lifting speed, shotcrete volume, and pump slurry pressure.

[0055] Before drilling a cement-soil mixing pile, clean the entire pipeline with water and check for blockages. Drilling can only begin after all the water has been drained. To ensure that the verticality of the cement-soil mixing pile meets regulatory requirements, hang a hammer on the main machine and control it by keeping the distance between the hammer and the drill pipe equal up, down, left, and right. Mix the cement slurry strictly according to the water-cement ratio of 1.0 determined by the process test, and the mixing time must not be less than 3 minutes. The slurry pump pressure is normally controlled at 0.6MPa. During construction, the slurry pump pressure needs to be dynamically adjusted according to the soil conditions to achieve the purpose of fully mixing the slurry and the soil.

[0056] The quality control standards are as follows:

[0057] a Main control project:

[0058] ①Hole position deviation: ≤20mm;

[0059] ②Hole depth: meet design requirements;

[0060] ③Hole slope: meet design requirements;

[0061] ④ Slurry delivery volume: meet design requirements;

[0062] ⑤Pile diameter: meet design requirements.

[0063] ⑥Construction records: complete, accurate and clear.

[0064] bGeneral items:

[0065] ① Water-cement ratio: meet the process parameter requirements;

[0066] ②Stirring speed: meet the process parameter requirements;

[0067] ③ Lifting speed (m / min): meet the process parameter requirements;

[0068] ④Handling of special cases: does not affect the quality.

[0069] According to the "Water Conservancy and Hydropower Engineering Unit Construction Quality Acceptance Assessment Standard - Foundation Treatment and Foundation Engineering"

[0070] (SL633-2012) for quality standard control.

[0071] 7 days after the pile is formed, shallow excavation of the pile head should be carried out for inspection. The excavation depth should be more than 0.5m below the slurry stopping surface. Check the uniformity of mixing and measure the pile diameter. The number of inspections should be no less than 5% of the total number of piles.

[0072] On-site safety measures include:

[0073] 1. General Provisions

[0074] All personnel entering the site must wear safety helmets, are not allowed to wear slippers or high heels, and are not allowed to work barefoot. Playing and fighting are strictly prohibited during construction.

[0075] 2. Construction electricity safety

[0076] a. All power lines and electrical equipment must be installed by licensed electricians. Regular inspections and maintenance are performed by dedicated electricians. Unauthorized connection or unauthorized wiring by other personnel is prohibited.

[0077] b. All on-site construction power lines must use insulated conductors. Use rubber cables for mobile lines. Carefully inspect cables before use to ensure that no exposed cables are present. Overhead lines must be installed overhead and secured with insulation.

[0078] c. All electrical machinery equipment on site must be inspected and tested as required before use. After operation, turn off the power and lock the switch box to prevent accidents.

[0079] 3. Mechanical construction safety measures

[0080] a. Machine operators must undergo assessment and hold a certificate before taking up their posts. They must strictly follow the machine operating procedures.

[0081] b. Parked machinery must not intrude into the building's access limits and must be parked stably.

[0082] c. During implementation, a full-time safety officer will be appointed to direct the movement of machinery.

[0083] d. Safety officers must carefully study and master safety rules and precautions, and be proficient in the use of protective equipment. They must stay focused and at their posts, and promptly identify and eliminate potential safety hazards.

[0084] The above embodiments are only preferred embodiments of the present invention. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also includes equivalent technical means that can be thought of by those skilled in the art based on the concept of the present invention.

Claims

1. A combined cement-soil mixing pile anti-seepage structure, used for embankment reinforcement, characterized by: The anti-seepage structure includes cement-soil mixing piles located in the middle of the embankment and steel sheet piles located at the foot of the slope on the water side of the embankment. The steel sheet piles are connected by H-shaped steel. The middle part of the steel sheet pile is a straight section, and an upper U-shaped opening and a lower U-shaped opening are respectively provided at both ends. The upper flange and the lower flange of the H-shaped steel are respectively snap-connected with the upper U-shaped opening and the lower U-shaped opening of the steel sheet pile. The depth of the cement-soil mixing pile corresponding to the straight section of the steel sheet pile is greater than the depth ΔH of the steel sheet pile, and the ΔH is not less than 1 / 10 of the distance between the steel sheet pile and the cement-soil mixing pile. The cement-soil mixing pile corresponding to the H-shaped steel is a reinforcement section. The length of the reinforcement section is not less than twice the length of the H-shaped steel, and the depth of the reinforcement section is greater than the depth 2ΔH of the steel sheet pile.

2. The combined cement-soil mixing pile anti-seepage structure according to claim 1, characterized in that: The distance between the steel sheet pile and the cement soil mixing pile is the distance between the center lines of the steel sheet pile and the cement soil mixing pile, and the length of the H-shaped steel is the distance between the top of the upper flange and the bottom of the lower flange of the H-shaped steel.

3. The combined cement-soil mixing pile anti-seepage structure according to claim 1, characterized in that: The upper U-shaped opening and the lower U-shaped opening are respectively adapted to the sizes of the upper flange and the lower flange of the H-shaped steel.

4. The combined cement-soil mixing pile anti-seepage structure according to claim 1, characterized in that: The cement content in the cement-soil mixing pile is 15% of the soil mass, and the water-cement ratio is 1.

0.

5. The construction method of the combined cement-soil mixing pile anti-seepage structure according to claim 1, characterized in that: The construction method comprises the following steps: S1: Construction is carried out during a dry period. The site is cleaned at the foot of the waterside slope of the embankment, the position of the steel sheet piles is located, and the line is laid out on site. Then, the guide frame is erected on site. S2: transport the steel sheet piles and H-shaped steel to the site, use a crane to lift the steel sheet piles and H-shaped steel into the pile insertion points, and connect the upper and lower flanges of the H-shaped steel to the upper and lower U-shaped openings of the steel sheet piles respectively; S3: Steel sheet piles and H-beams are driven in multiple stages. When the top of the steel sheet piles and H-beams is less than 1m from the ground, the guide frame is removed and the steel sheet piles and H-beams are driven to the designed elevation. After all the steel sheet piles and H-beams are driven in, the site is cleaned up. S4: Use machinery to break up the concrete pavement of the original embankment road, clean and level the construction site with manual labor and machinery, and use an excavator to dig a guide ditch along the axis of the cement-soil mixing pile; S5: Positioning and laying out, the pile driver is in place, soil, cement and water are mixed in proportion in the slurry tank, the mixed slurry is pumped into the slurry storage tank, and stirred continuously to make it uniform and stable. The slurry should be screened when it is pumped into the slurry storage tank; S6: Start the pile driver. After the rotating speed of the mixing drill bit is normal, sink the drill rod while stirring. After sinking to the designed depth, start the mortar pump to deliver slurry to the slurry outlet of the mixing drill bit through the pipeline. After the slurry is discharged, start the pile driver. Slurry is sprayed and stirred while the drill rod is lifted at the lifting speed determined by the design to fully mix the slurry and soil. S7: After the mixing drill bit is lifted to a height of 500mm above the pile top, the mortar pump is turned off and the mortar is stirred and sunk to the designed depth. After sinking to the designed depth, the mortar is sprayed and mixed and lifted until the pile is formed; S8: The pile driver moves to the next pile position and repeats steps S6-S7 until the construction of all cement-soil mixing piles is completed.

6. The construction method according to claim 5, wherein: When laying out the S5, the depth of the corresponding cement soil mixing pile is first determined based on the position of the steel sheet pile and the H-shaped steel, and the cement soil mixing pile in the reinforcement section is specially marked. When constructing the cement soil mixing pile in the reinforcement section, the construction is carried out according to the preset depth.

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