Digital intelligent steel pipe pile and construction method

Abstract

The invention discloses a digital intelligent steel pipe pile and a construction method, and belongs to the technical field of foundation pit supporting. The steel pipe pile body is of a hollow structure, adjacent pile bodies are connected in an engaged mode through buckles, the grouting channel is formed by welding a steel plate and the buckles, grout outlet holes are formed, and strain gauges are arranged to monitor the strain around the pile. And the matched intelligent control system calculates frictional resistance through strain data, and dynamically controls the grouting pressure and amount based on a big data model. The construction method comprises the steps of injecting anti-drag grout during pile sinking and filling grout during pile pulling, and intelligent construction is achieved. The method is suitable for engineering scenes such as urban underground space development and bridge construction.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit support and cofferdam engineering, and particularly relates to a digital steel pipe pile integrating intelligent sensing and resistance-reducing grouting technology and a construction method thereof, which is applicable to engineering scenarios such as urban underground space development, cross-river and cross-sea bridge construction, artificial island building, etc. that require steel pipe pile support. Background Art

[0002] In major projects such as urban underground space development, cross-river and cross-sea bridge construction, and artificial island building, foundation pit support and cofferdam construction are key links to ensure the safe progress of the project. As an important engineering structural material, steel pipe piles have significant advantages. They have high strength, good toughness, can bear large loads, and have good bending and shear resistance. The construction speed is fast, and various pile driving methods such as vibration and static pressure can be adopted, which can effectively shorten the construction period. Their cross-sectional forms are diverse, can be flexibly designed according to engineering requirements, and are recyclable, meeting the concept of green construction. Therefore, they are widely used in engineering fields such as foundation pits and cofferdams. However, in the actual application process, the friction between the steel pipe pile and the soil makes the pile driving difficult and requires a large amount of mechanical energy. Especially in hard soil layers or complex geological conditions, the pile driving efficiency is significantly reduced. When pulling out the steel pipe pile, the excessive friction between the pile and the soil and the loss of soil around the pile easily cause ground settlement or deformation of surrounding buildings. Traditional backfilling processes (such as sand filling and soil filling) are difficult to effectively fill the voids, posing safety hazards. The existing steel pipe pile construction relies on experience control, lacks a real-time monitoring and dynamic adjustment mechanism, and cannot accurately match the change of frictional resistance under complex geological conditions. How to real-time monitor the stress change of the soil around the pile and dynamically adjust the construction parameters; how to achieve the integrated operation of grouting resistance reduction and void filling through structural optimization; how to improve the stiffness and sealing performance of the steel pipe pile connection node to ensure the coordinated force of multiple piles. The traditional technology has not solved the following technical bottlenecks. Therefore, it is necessary for the industry to develop a digital steel pipe pile and construction method to effectively reduce the friction between the pile and the soil. Summary of the Invention

[0003] The present invention aims to provide a digital steel pipe pile and construction method, which reduce the pile-soil frictional resistance during pile driving and pulling out through structural innovation and intelligent control system integration, and improve the construction efficiency; dynamically adjust the grouting parameters by real-time monitoring the strain around the pile, reduce energy consumption and environmental disturbance; and synchronously grout to fill the voids when pulling out the pile, avoiding secondary construction and improving safety and economy.

[0004] To achieve the above object, the present invention provides a digital intelligent steel pipe pile, comprising a steel pipe pile, a buckle and a grouting channel. The main body of the steel pipe pile is a hollow structure with openings at both ends; the buckle is welded along the entire length of the outer side of the steel pipe pile, and adjacent steel pipe piles are connected by buckle engagement; the grouting channel is formed by welding a steel plate and a buckle to form a triangular cross-section, and is arranged longitudinally along the pile body. Slurry outlet holes are provided at the bottom of the steel plate and the steel pipe below the grouting channel.

[0005] The grouting channel is formed by welding a steel plate and a buckle to form a triangular cross-section. The triangular cross-section is a mechanically stable structure. By welding the steel plate and the buckle, the stiffness and integrity of the connection node between the buckle and the steel pipe pile are significantly enhanced, ensuring the coordinated force of multiple piles and improving the stability of the support structure. The longitudinal arrangement enables the slurry to be evenly transported along the entire length of the pile body. The slurry outlet holes (matrix distribution) at the bottom of the lower steel plate and the steel pipe ensure that the slurry seeps out synchronously from the inner and outer peripheries of the pile body side wall, covering the entire pile-soil contact surface, realizing resistance reduction along the entire pile length during pile sinking and void filling at the full depth after pile pulling, and avoiding local frictional resistance concentration or incomplete filling. The integrated structure design integrates the functions of resistance reduction grouting and void filling into the same channel. During pile sinking, bentonite slurry is injected for resistance reduction, and during pile pulling, cement slurry is injected for filling, without the need for additional equipment or secondary construction, shortening the process cycle and reducing the construction cost.

[0006] Further, the slurry outlet holes are arranged in a matrix on the steel plate and the main body of the steel pipe, with a hole diameter of 5 - 10 mm and a hole spacing of 150 - 250 mm. The matrix distribution enables the slurry to seep out evenly along the circumferential and longitudinal directions of the pile body, covering the pile-soil contact surface in the entire pile length range, avoiding local frictional resistance concentration or incomplete void filling, and ensuring the continuity and consistency of the resistance reduction effect during pile sinking and the filling effect during pile pulling. The hole diameter of 5 - 10 mm is suitable for the fluidity of common slurries such as bentonite slurry and cement slurry, avoiding slurry blockage caused by too small a hole diameter and preventing out-of-control slurry diffusion and insufficient pressure caused by too large a hole diameter, ensuring that the slurry penetrates into the soil gap at a reasonable pressure to form an effective resistance reduction layer or filling body. The hole spacing of 150 - 250 mm takes into account the slurry diffusion range and the drilling density, while ensuring that the slurry penetration areas of adjacent slurry outlet holes overlap (forming a continuous grouting zone), reducing the number of ineffective drill holes, reducing the processing cost and the risk of weakening the pile body structure, and improving the construction efficiency.

[0007] Further, strain gauges are arranged circumferentially on the outer surface of the steel pipe pile, with a monitoring section set every 0.5 - 1.5 m, and 4 strain gauges are evenly arranged in each section.

[0008] On the other hand, the present invention provides an intelligent control system for digital and intelligent steel pipe pile construction, which is applicable to the above-mentioned steel pipe piles, and includes a grouting pipeline, a slurry pool, strain gauges around the pile, a data transmission line, a data analysis module, a data storage module, a display device, a manual input unit for grouting pressure, a grouting pressure control unit, and a high-pressure grouting device; the strain gauges are arranged on the outer periphery of the steel pipe pile, and 4 strain gauges are evenly arranged in each cross-section, with the cross-section spacing being 0.5-1.5 m; the data analysis module calculates the skin friction of the pile side through strain data and generates a grouting control instruction based on a big data model; the data transmission line mainly transmits the monitoring data of the strain gauges during the construction of the steel pipe pile; the data storage module is mainly used to store the process and results of data analysis; the display device mainly displays the results of data analysis; the grouting pressure control unit mainly controls the high-pressure grouting device, receives the grouting pressure and grouting volume data from the data analysis module, and controls grouting according to the received data; at the same time, the grouting pressure control unit can also receive the instruction of manual input data and control grouting according to the requirements of manual input; the manual input unit for grouting pressure mainly provides an interface for manually inputting grouting pressure and grouting volume, and can manually control grouting; one end of the high-pressure grouting device is connected to the slurry pool, and the other end is connected to the grouting pipeline to grout into the grouting channel. The high-pressure grouting device mainly provides grouting pressure and controls the grouting volume, and receives the instruction of the grouting pressure control unit; the grouting pipeline connects the high-pressure grouting device and the grouting channel on the steel pipe pile, injects the slurry into the grouting channel, and the grouting pipeline is tightly connected to the grouting channel to ensure sealing; the main function of the slurry pool is to store the slurry.

[0009] Further, the data analysis module has a built-in skin friction calculation formula: ; ; ; In the formula, E is the elastic modulus of the steel pipe pile; ε is the monitoring data of the strain gauge; n is i the number of strain gauges at the cross-section; i is the compressive stress at the cross-section; i is the internal friction angle of the soil at the cross-section, which can be determined according to geological exploration data; i is the cohesion of the soil at the cross-section, which can be determined from geological exploration data; i is the shear strength of the soil at the surface of the pile body at the D cross-section; D 1 is the inner diameter of the steel pipe pile;L is the length of the steel pipe pile; From the above formula, the friction resistance around the pile is: .

[0010] Furthermore, the high-pressure grouting equipment has an output pressure of 0-20 MPa and a flow rate of 0-150 L / min, and can inject bentonite slurry or cement slurry. The grouting pipe and the grouting channel are connected by flange sealing.

[0011] In one aspect, the present invention further provides a digital steel pipe pile construction method, which uses the above-mentioned digital steel pipe pile construction intelligent control system, and includes the following steps: S1, level the site, measure and mark the position of steel pipe piles; S2, construction positioning guide beam, control guide beam elevation and verticality; S3, drive the first steel pipe pile by static pressure, vibration or hammer pile sinking, inject drag reduction slurry through the grouting channel simultaneously, and dynamically adjust the grouting parameters according to strain monitoring; S4, driving subsequent steel pipe piles in sequence and connecting them by snap-fitting to form a continuous wall; S5, after the main structure construction is completed, the steel pipe piles are removed and the filling slurry is injected simultaneously.

[0012] Furthermore, the drag reduction slurry is bentonite slurry with a density of 1.05-1.2 g / cm 3 The filling slurry is M10-M15 cement slurry with a water-cement ratio of 0.45-0.55.

[0013] Furthermore, during the pile sinking process, when the friction resistance on the pile side exceeds 80% of the design value, the grouting pressure is automatically increased to 1.0-2.0MPa; when pulling out the pile, the grouting pressure and the pile pulling speed are controlled in conjunction to ensure that the gaps are filled densely.

[0014] Furthermore, the intelligent control algorithm based on big data analysis determines the grouting pressure and post-grouting volume according to the friction analysis around the pile, and outputs the instructions and calculation results to the data storage module, and displays them on the display device; when the friction resistance around the pile is large, the grouting pressure and grouting volume are correspondingly large; when the friction resistance on the pile side decreases, the grouting pressure and grouting volume are correspondingly reduced; when the friction resistance on the pile side is maintained at a small value, the grouting can be stopped according to the actual situation.

[0015] Beneficial effects of the present invention: (1) The snap-on connection enhances the coordinated force and sealing of the pile body, achieving water-stopping and soil-retaining. The grouting channel and the pile body are designed as an integrated whole, combining the functions of pile sinking and drag reduction and pile pulling and filling, thus avoiding secondary construction. The matrix distribution of the grouting holes optimizes the grout penetration effect and improves the drag reduction and filling efficiency.

[0016] (2) The strain gauge is combined with the big data model to calculate the friction resistance of the pile side in real time, automatically match the grouting parameters (pressure, flow), accurately respond to complex geological conditions, and reduce reliance on manual experience. When the friction resistance exceeds the threshold during pile sinking, the grouting is automatically pressurized. When the pile is pulled out, the pressure and speed are linked to ensure that the gaps are filled densely and reduce the risk of ground subsidence.

[0017] (3) Static pressure / vibration / hammer pile driving combined with drag reduction grouting reduces pile driving energy consumption and improves construction efficiency; recyclable steel pipe piles are in line with the concept of green construction. Bentonite slurry and cement slurry are used for drag reduction and filling respectively. The materials are environmentally friendly and reduce soil disturbance and environmental pollution. The intelligent control system integrates data monitoring, analysis, storage and display functions to improve construction safety and traceability. The continuous wall is connected by snap-fit to form an overall structure, which enhances the support stiffness and ensures the safety of the foundation pit and cofferdam projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the front view of the steel pipe pile.

[0019] Figure 2 This is a schematic diagram of the overall appearance of steel pipe piles.

[0020] Figure 3 This is an enlarged view of the grouting hole at the bottom of the grouting channel.

[0021] Figure 4 It is a schematic diagram of the slurry intelligent control system.

[0022] Description of Figure Numbers: 1-Steel pipe pile; 2-Snap buckle; 3-Grouting channel. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections.

[0025] In order to simplify the drawings, only the parts related to the present invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0026] It should also be further understood that the term "and / or" used in the specification and appended claims of the present application refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0027] In the embodiments shown in the drawings, the indication of directions (such as up, down, left, right, front and back) is used to explain that the structures and movements of various components of the present invention are not absolute but relative. When these components are in the positions shown in the drawings, these descriptions are appropriate. If the descriptions of the positions of these components change, the indication of these directions also changes accordingly.

[0028] In addition, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation manners of the present invention will be described below with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings, and other implementation manners can also be obtained.

[0030] The steel pipe pile structure proposed in this embodiment is as Figures 1-3 shown, including 1 - steel pipe pile, 2 - buckle, 3 - grouting channel. The details of each part are introduced as follows: 1) The steel pipe pile is of a hollow structure with both ends open and is the main load-bearing structure. It is inserted into the soil layer and jointly bears the load with the soil through the steel pipe. The length of the steel pipe pile can be welded and lengthened according to actual needs; 2) The buckle is connected to the steel pipe pile by welding and is arranged along the entire length on the outer side of the steel pipe pile. Adjacent two steel pipe piles are connected by the buckle. The buckle bite can stop water and retain soil, enabling multiple steel pipe piles to bear force synergistically; 3) The grouting channel is a triangular channel formed by a steel plate and a steel pipe buckle. The steel plate should be firmly welded to the steel pipe and the buckle. Structurally, it significantly improves the integrity and stiffness of the buckle and the steel pipe pile. There are slurry outlet holes on both the steel plate and the steel pipe below the grouting channel to ensure that after grouting, the slurry can seep around the inner and outer peripheries of the steel pipe side wall, realizing the resistance reduction effect during the driving and extraction of the steel pipe pile.

[0031] The slurry intelligent control system in this embodiment mainly consists of a pile perimeter strain gauge, a data transmission line, a data analysis module, a data storage module, a display device, a grouting pressure control unit, a grouting pressure manual input unit, a high-pressure grouting device, a grouting pipeline, a slurry pool, etc. See the schematic diagram in Figure 4 for details. The details of each part are introduced as follows: 1) The strain gauges are pasted on the outer periphery of the steel pipe pile, with 4 pasted on each cross-section and one strain gauge monitoring cross-section set every 1 m to monitor the strain during the construction of the steel pipe pile in real time. The strain gauges and their data transmission lines are closely attached to the steel pipe pile and are strengthened to avoid damage. 2) The data transmission line mainly transmits the monitoring data of the strain gauges during the construction of the steel pipe pile. 3) The data analysis module mainly analyzes the skin friction of the pile by receiving the strain data around the pile and calculates the grouting pressure required for big data artificial intelligence analysis. The formula for the skin friction of the pile is: ; ; ; In the formula, E is the elastic modulus of the steel pipe pile; ε is the monitoring data of the strain gauge; n is i the number of strain gauges at the cross-section; is i the compressive stress at the cross-section; is i the angle of internal friction of the soil at the cross-section, which can be determined according to the geological exploration data; is i the cohesion of the soil at the cross-section, which can be determined from the geological exploration data; is i the shear strength of the soil on the surface of the pile body at the cross-section; D 1 is the inner diameter of the steel pipe pile; D 2 is the outer diameter of the steel pipe pile; L is the length of the steel pipe pile; From the above formula, the skin friction around the pile is: .

[0032] Then, using big data artificial intelligence, the grouting pressure and the post-grouting volume are determined based on the analysis of the skin friction around the pile, and the instructions and calculation results are output to the data storage module and displayed on the display device. When the skin friction around the pile is large, the grouting pressure and the grouting volume are correspondingly large; when the skin friction on the pile side decreases, the grouting pressure and the grouting volume are correspondingly reduced; when the skin friction on the pile side remains at a small value, the grouting can be stopped according to the actual situation.

[0033] 4) The data storage module is mainly used to store the process and results of data analysis; 5) The display device mainly displays the results of data analysis; 6) Grouting pressure control unit, which mainly controls the high-pressure grouting equipment, receives the grouting pressure and grouting volume data from the data analysis module, and controls the grouting according to the received data. At the same time, the grouting pressure control unit can also receive the instruction of manually inputting data and control the grouting according to the requirements of manual input. 7) Manual input unit for grouting pressure, which mainly provides an interface for manually inputting grouting pressure and grouting volume, and can manually control the grouting. 8) High-pressure grouting equipment, which mainly provides grouting pressure and controls the grouting volume, and receives the instruction of the grouting pressure control unit. 9) Grouting pipeline, which connects the high-pressure grouting equipment and the grouting channel on the steel pipe pile, injects the slurry into the grouting channel, and the grouting pipe is tightly connected to the grouting channel to ensure sealing. 10) Slurry pool, whose main function is to store the slurry.

[0034] Another specific implementation plan for the digital and intelligent construction of steel pipe piles is as follows: The first step is to level the construction site and measure and set out the construction position of the steel pipe pile.

[0035] The second step is to construct the positioning guide beam for the steel pipe pile.

[0036] The third step is to drive the first digital and intelligent steel pipe pile. It mainly adopts static pressure or vibration pile sinking, and hammer pile sinking is also used in areas with low environmental requirements. During the driving process, bentonite slurry is injected synchronously through the grouting channel to reduce the side friction resistance around the pile. According to the lateral strain of the steel pipe pile, the grouting pressure and grouting volume are automatically adjusted in real time by the intelligent system. When the side friction resistance around the pile is large, the corresponding grouting pressure and grouting volume are large; when the side friction resistance of the pile decreases, the grouting pressure and grouting volume are correspondingly reduced; when the side friction resistance of the pile remains at a small value, the grouting can be stopped according to the actual situation; when the construction experience of steel pipe piles in the area is relatively rich, the grouting parameters can also be directly input manually for manual control of grouting. The length of the steel pipe pile can be welded and lengthened according to the actual engineering needs.

[0037] The fourth step is to repeat the third step to drive the adjacent second digital and intelligent steel pipe pile. The steel pipe piles are connected by buckles to ensure tight connection.

[0038] The fifth step is to repeat the third step and the fourth step until all the steel pipe piles are constructed.

[0039] Step 6: When the main structure construction is completed and the steel pipe piles are pulled out, inject cement slurry synchronously through the grouting channels, and adjust the grouting pressure and grouting volume automatically in real time by the intelligent system according to the lateral strain of the steel pipe piles. At this time, the cement slurry has two functions. First, it reduces the lateral friction resistance of the steel pipe piles and reduces the impact of pile pulling construction on the soil layer and the surrounding environment. Second, it fills the voids after the steel pipe piles are pulled out to avoid the subsequent ground settlement caused by the voids after the steel pipe piles are pulled out.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A digital intelligent steel pipe pile, comprising a steel pipe pile (1), a buckle (2) and a grouting channel (3), characterized in that: The steel pipe pile body is a hollow structure with openings at both ends; the buckles are welded along the entire length of the outer side of the steel pipe pile, and adjacent steel pipe piles are connected by the buckles engaging with each other; the grouting channel is formed by welding a steel plate and the buckles to form a triangular cross-section and is arranged longitudinally along the pile body. The steel plate and the bottom of the steel pipe below the grouting channel are both provided with slurry outlet holes.

2. The steel pipe pile according to claim 1, characterized in that: The slurry outlet holes are arranged in a matrix on the steel plate and the steel pipe body, with a hole diameter of 5 - 10 mm and a hole spacing of 150 - 250 mm.

3. The steel pipe pile according to claim 1, wherein: Strain gauges are arranged circumferentially on the outer surface of the steel pipe pile (1), with a monitoring section set every 0.5 - 1.5 m, and 4 strain gauges are evenly arranged in each section.

4. A digital intelligent control system for steel pipe pile construction, applicable to the steel pipe piles described in any one of claims 1-3, characterized in that: It includes a grouting pipeline, a slurry pool, strain gauges around the pile, a data transmission line, a data analysis module, a data storage module, a display device, a manual grouting pressure input unit, a grouting pressure control unit, and a high-pressure grouting device; the strain gauges are arranged on the outer circumference of the steel pipe pile, and 4 strain gauges are evenly arranged in each monitoring section, with a section spacing of 0.5 - 1.5 m; the data analysis module calculates the side friction resistance of the pile through the strain data and generates a grouting control instruction based on a big data model; the data transmission line mainly transmits the monitoring data of the strain gauges during the construction process of the steel pipe pile; the data storage module is mainly used to store the process and results of data analysis; the display device mainly displays the results of data analysis; the grouting pressure control unit mainly controls the high-pressure grouting device, receives the grouting pressure and grouting volume data from the data analysis module, and controls the grouting according to the received data; at the same time, the grouting pressure control unit can receive the instruction of manually inputting data and control the grouting according to the requirements manually input; the manual grouting pressure input unit mainly provides an interface for manually inputting the grouting pressure and grouting volume and can manually control the grouting; one end of the high-pressure grouting device is connected to the slurry pool, and the other end is connected to the grouting pipeline to grout into the grouting channel. The high-pressure grouting device mainly provides the grouting pressure and controls the grouting volume, and receives the instruction of the grouting pressure control unit; the grouting pipeline connects the high-pressure grouting device and the grouting channel on the steel pipe pile, injects the slurry into the grouting channel, and the grouting pipeline is tightly connected to the grouting channel to ensure sealing; the slurry pool mainly functions to store the slurry.

5. The intelligent control system for digital and intelligent steel pipe pile construction according to claim 4, wherein: The data analysis module has a built-in friction resistance calculation formula: ； ； ； In the formula, E is the elastic modulus of the steel pipe pile; ε is the monitoring data of the strain gauge; n is i the number of strain gauges at the section; i is the compressive stress at the section; i is the internal friction angle of the soil at the section, which can be determined according to the geological exploration data; i is the cohesion of the soil at the section, which can be determined from the geological exploration data; i is the shear strength of the soil at the surface of the pile body at the D section; 1 is the inner diameter of the steel pipe pile; D 2 is the outer diameter of the steel pipe pile; L is the length of the steel pipe pile; From the above formula, the side friction resistance of the pile is: 。 6. The intelligent control system for digital and intelligent steel pipe pile construction according to claim 4, characterized in that: The output pressure of the high-pressure grouting device is 0 - 20 MPa, and the flow rate is 0 - 150 L / min. It can inject bentonite slurry or cement slurry, and the grouting pipeline and the grouting channel are sealed and connected by a flange.

7. A digital intelligent steel pipe pile construction method, which adopts the digital intelligent steel pipe pile construction intelligent control system described in any one of claims 4-6, and is characterized in that: It includes the following steps: S1, level the site and measure and set out the positions of the steel pipe piles; S2, construct the positioning guide beam and control the elevation and verticality of the guide beam; S3, drive the first steel pipe pile by means of static pressure, vibration or hammer-driven pile sinking, and simultaneously inject the friction-reducing slurry through the grouting channel, and dynamically adjust the grouting parameters according to the strain monitoring; S4, drive the subsequent steel pipe piles in sequence and form a continuous wall through the connection of the buckles; S5, after the main structure construction is completed, pull out the steel pipe piles and simultaneously inject the filling slurry.

8. The construction method according to claim 7, characterized in that: The drag reducing slurry is bentonite mud with a density of 1.05 - 1.2 g / cm 3 , and the filling slurry is M10 - M15 cement slurry with a water-cement ratio of 0.45 - 0.

55.

9. The construction method according to claim 7, characterized in that: During the pile driving process, when the skin friction of the pile exceeds 80% of the design value, the grouting pressure is automatically increased to 1.0 - 2.0 MPa; during pile extraction, the grouting pressure is linked with the pile extraction speed to ensure that the voids are filled densely.

10. The construction method according to claim 7, characterized in that: Based on the intelligent control algorithm of big data analysis, the grouting pressure and the post-grouting volume are determined according to the analysis of the friction force around the pile, and the instructions and calculation results are output to the data storage module and displayed on the display device; when the friction force around the pile is large, the corresponding grouting pressure and grouting volume are large; when the skin friction of the pile decreases, the grouting pressure and grouting volume are correspondingly reduced; when the skin friction of the pile remains at a small value, grouting can be stopped according to the actual situation.

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